Design and Execution of Steel Structures and Composite Steel-concrete Buildings

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AUG 2003 Draft Revision of ISO 8800 Design and execution of steel structures and composite steel-concrete buildings Procedure Source: NBR 8800:1986 CB-02: Brazilian Committee on Construction EC 02: NBR 8800:200 x - Design and construction of steel and composite structures for buildings Descriptors: Design and construction. Steel structures. Steel and concrete composite structures. Buildings. It is planned to cancel and replace the full NBR 8800:1986 Keywords: Design and implementation structures, structures 289 pages steel, composite steel-concrete structures, buildings

Abstract Foreword Introduction Objective 1 2 Normative References 3 Definitions, symbols and units 4 General conditions of project 5 Specific conditions for sizing steel elements 6 Specific conditions for design of steel connections 7 Specific conditions for design of steel-concrete composite members 8 Specific conditions for design of composite joints 9 Additional Considerations resistance 10 Additional conditions of project 11 limit states 12 Manufacturing, assembly and quality control Annex A (Normative) - structural steel and metal bonding materials Annex B (Normative) - AP Annex C (Normative) - Recommended maximum displacements Annex D (Normative) - Bending Moment resistant characteristic of non-slender beams Annex E (Normative) - Local Buckling in compressed bars Annex F (Normative) - Bending Moment resistant characteristic of slender beams Annex G (Normative) - shear force resistant characteristics including the effect of field drift Annex H (Normative) - Length buckling by bending and twisting of compressed bars Annex J (Normative) - Length buckling by bending the pillars of continuous structures Annex K (normative) - Normal force of elastic buckling Annex G (Normative) - Openings souls of beams Annex F (Normative) - Fatigue Annex C (Normative) - Particular requirements for bars of varying section Annex E (Normative) - Best practices for implementing structures Annex Q (normative) - Beams composite steel-concrete Annex R (normative) - Pillars mixed steel-concrete Annex S (normative) - steel-concrete composite slabs Annex T (normative) - steel-concrete composite connections Annex U (normative) - Control of cracking in concrete composite beams Annex V (Normative) - Procedures for approximate elastic second-order analysis

Annex (Normative)-- Orientation Guidance for floor vibration Annex W X (Normative) to in vibrations due to wind

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NBR 8800 - Based Text Revision

Foreword ABNT - Brazilian Association of Technical Standards - is the National Standardization Forum. The Brazilian Standards, whose content is the responsibility of the Brazilian Committees (CB) and Standardization Bodies Sector (ONS), are prepared by Study Groups (EC), formed by representatives of the sectors involved including: producers, consumers and neutral (universities, laboratories and others). The Brazilian Standard projects, developed through CB and ONS circulate to Vote National ABNT among members and other interested parties. This standard contains Annexes A, B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, T, U, V and W normative character. This standard cancels and replaces in its entirety NBR 8800:1986 - Design and implementation of steel structures for buildings - Procedure. This standard includes the steel-concrete composite columns, the steel-concrete composite slabs and links composite steel-concrete, which were not foreseen in the NBR 8800:1986 - Design and implementation of steel structures for buildings - Procedure. Introduction For the development of this standard philosophy of the previous was maintained: NBR 8800, so that the this standard set fits the general criteria governing the design ambient temperature and implementation of structural steel and composite steel-concrete structures of buildings. Thus, it should be complemented by other rules which establish criteria for specific structures. Objective 1 1.1 This standard, based on the method of limit states, the general principles that should be followed in the design room temperature and execution, including inspection, structures of steel and steel-concrete composite structures for buildings in which: - Profiles are rolled or welded steel; - The elements of steel sections, plates and bars have thickness less than 3 mm; - Connections are bolted or welded or composite steel-concrete. A related type of profile requirement does not apply to steel formwork slabs of composite steelconcrete and the shear connectors C profile cold-formed, and related to the thickness steel formwork at least mentioned, shims and filler plates. The requirements of this standard apply only to steel profiles non-hybrids. Case hybrid profiles are used, the necessary adjustments must be made. 1.2 The steel-concrete composite structures, including steel-concrete composite joints, provided by this Standard are those formed by components of steel and concrete, reinforced or otherwise, working together. The concrete may be of normal density or low density

except when some restriction is made ​ in a specific part of the Standard.

Page 3 NBR 8800 - Based Text Revision 1.3 Profiles, rolled or welded shall be constructed obeying the Brazilian standards applicable. In the absence of such standards, it is permissible to use test results from the literature specialized or foreign standards or specifications, as provided in 1.7. Profiles soldiers can be fabricated by depositing weld metal or by electro-fusion. 1.4 The general principles in this standard apply to building structures for housing and commercial and industrial uses and public buildings, and the solutions usual for bars and links. Also apply to structures pedestrian walkways. 1.5 To strengthen or repair of existing structures, the application of this standard may require study and special adaptation to take into account the date of construction, type and quality of materials were used. 1.6 The design of a structure made ​ in accordance with this Standard should follow coherently all your criteria. 1.7 The responsibility for the design shall identify all applicable limit states, even though some are not mentioned in this standard, and design the structure so that they do not are violated. For types of structures or situations not covered by this standard, or covered simply, it is permissible to use test results, professional literature or foreign standards or specifications. In such cases, the responsibility for the project, if necessary, shall make the necessary adjustments to maintain the level of security provided by this Standard. Additionally, tests may be performed following procedures are internationally accepted, the relevant literature used should have recognition and acceptance by the international technical community and the standards and specifications foreign should be internationally recognized and ready to use, being valid. 2 Normative References The standards listed below contain provisions which, through reference in this text, constitute provisions of this Standard. Editions indicated were valid at the time this publication. All standards are subject to revision, we recommend to those who perform agreements based on this to verify the possibility of applying the most recent editions of standards listed below. ABNT has the information of the Brazilian Standards in force any given time. ASME B18.2.6: 1996 - Fasteners for use in structural applications ASME B46.1: 2002, 2003 - Surface texture, surface roughness, waviness and lay ASTM A6/A6M: 2001b - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling ASTM A108: 1999 - Standard Specification for Steel Bars, Carbon, Cold-Finished, Standard Quality ASTM A307: 2000 - Standard specification for carbon steel bolts and studs, 60,000 PSI tensile strength ASTM A325: 2000 - Standard specification for structural bolts, steel, heat-treated, 120/105 ksi minimum tensile strength

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ASTM A325M: 2003 - Standard Specification for Structural Bolts, Steel Heat Treated 830 MPa Minimum Tensile Strength [Metric] ASTM A490: 2000 - Standard specification for steel heat-treated structural bolts, 150 ksi minimum tensile strength ASTM A490M: 2000 Standard Specification for High-Strength Steel Bolts, Classes 10.9 and 10.9.3, for Structural Steel Joints [Metric] ASTM A568/A568M: 2003 - Standard Specification for Steel, Sheet, Carbon, and High-Strength, Low-Alloy, Hot-Rolled and Cold-Rolled, General Requirements for ASTM A588/A588M: 2001 - Standard Specification for High-Strength Low-Alloy Structural Steel with 50 ksi [345 MPa] Minimum Yield Point to 4-in. [100 mm] Thick ASTM A668/A668M: 2002 - Standard Specification for Steel Forgings, Carbon and Alloy, for General Industrial Use ASTM A913/A913M: 2001 - Standard Specification for High-Strength Low-Alloy Steel Shapes of Structural Quality, Produced by Quenching and Self-Tempering Process (QST) ASTM F436: 2002 - Standard Specification for Hardened Steel Washers AWS A2.4: 1998 - Standard symbols for welding, brazing, and nondestructive examination AWS A5.1: 2003 - Specification for carbon steel electrodes for shielded metal arc welding AWS A5.5: 1996 - Specification for low-alloy steel electrodes for shielded metal arc welding AWS A5.17: 1997 - Specification for carbon steel electrodes and fluxes for submerged arc welding AWS A5.18: 2001 - Specification for carbon steel filler metals for gas shielded arc welding AWS A5.20: 1995 - Specification for carbon steel electrodes for flux cored arc welding AWS A5.23: 1997 - Specification for low-alloy steel electrodes and fluxes for submerged arc welding AWS A5.28: 1996 - Specification for low-alloy steel electrodes for gas shielded arc welding AWS A5.29: 1998 - Specification for low-alloy steel electrodes for flux cored arc welding AWS D1.1: 2002 - Structural welding code - steel ISO 898-1:1999 - Mechanical properties of fasteners made ​ of carbon steel and alloy steel - Part 1: Bolts, screws and studs NBR 5000:1981 - Heavy plate steel, low alloy and high strength NBR 5004:1981 - thin sheets of steel, low alloy and high strength

Page 5 NBR 8800 - Based Text Revision NBR 5008:1997 - Heavy plate and thick coils, low alloy steel, corrosion resistant Atmospheric, for structural use - Requirements NBR 5920:1997 - thin cold and thin cold rolled coils sheets, low alloy steel, resistant atmospheric corrosion for structural use - Requirements NBR 5921:1997 - Hot Tin plates and thin hot rolled coil steel, low alloy, resistant to atmospheric corrosion, for structural use - Requirements NBR 6118:2003 - Design of concrete structures NBR 6120:1980 - Loads for calculation of building structures NBR 6123:1988 - Forces due to wind on buildings NBR 6313:1986 - Part molten carbon steel for general use NBR 6648:1984 - Heavy plate carbon steel for structural use NBR 6649:1986 - Cold Plates thin carbon steel for structural use NBR 6650:1986 - Hot thin sheets of carbon steel for structural use NBR 7007:2002 - Steels for structural carbon and microalloyed use and general NBR 7188:1984 - Mobile loads on road bridges and pedestrian walkways NBR 7242:1990 - Part fused high-strength steel for structural purposes NBR 8261:1983 - Tubular Profile, carbon steel, cold shape, with and without sewing section circular, square or rectangular for structural uses NBR 8681:2003 - Stocks and security structures NBR 14323:1999 - Design of steel structures of buildings in fire NBR 14762:2001 - Design of steel structures consist of cold formed profiles Research Council on Structural Connections: 2000 - Specification for structural joints using ASTM A325 or ASTM A490 bolts 3 Definitions, symbols and units 3.1 Definitions For the purposes of this International Standard, the following definitions: 3.1.1 Action: Any influence or set of influences can produce stress states or deformation or rigid body motion in a structure. 3.1.2 share calculation: value per share used in the design of the structure.

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3.1.3 Structural Steel: Steel produced based on the specification that classifies as structural and establishes the chemical composition and mechanical properties. 3.1.4 Structural analysis: Determination of the effects of actions (normal force, shear force, bending moment, stress, displacement, etc..) bars and links. 3.1.5 rod: Component structure wherein the length is much greater than the dimensions the cross section. 3.1.6 weighting resistance: Value by which the resistance should be divided characteristic to take into account uncertainties inherent in and get the same resistance calculation (see 3.1.16). 3.1.7 Unlocked length: Length between two sections contained laterally (see 3.1.18). 3.1.8 component: a constituent part of a profile as table, soul, tab, etc., or bar or whatever. another component of the structure. 3.1.9 limit states: states from which a structure no longer fulfills the purpose for which it was designed. 3.1.10 limit states: States that, by its occurrence, repetition or duration cause effects incompatible with the conditions of use of the structure, such as dislocations excessive, permanent deformations and vibrations. Also called limit states service. 3.1.11 ultimate limit states: corresponding to the ruin of the whole structure states, or part of same, by rupture, excessive plastic deformation, instability, etc.. 3.1.12 element width: width of the flat portion of a constituent element of a profile, measured in the plane of the cross section. 3.1.13 Hybrid Profile: Profile elements whose components have steels with properties different. 3.1.14 non-hybrid Profile: Profile elements whose components have the same steel. 3.1.15-thickness aspect ratio: ratio between the flat part of a constituent element of a profile and thickness. 3.1.16 Calculation of resistance: Resistance value used in the design of the structure. It obtained from the characteristic value of the material properties and the sections together with a formula deduced rationally, based on analytical and / or experimental model, and that represents the element's behavior in the limit state. Resistance calculation is equal the characteristic resistance value divided by a coefficient that takes into account the uncertainties attached thereto. 3.1.17 characteristic strength: Value set from tests or some rational method connected to a resistance property.

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3.1.18 section contained laterally: Section compressed whose face has its lateral displacement prevented or impeded submit twist. 3.1.19 tubular section: circular or rectangular hollow section steel with uniform thickness, laminated or formed by cold working with continuous longitudinal weld. 3.1.20 characteristic value of shares: A value that quantifies the actions provided for in the rules of actions and set the NBR 8681. A action with its characteristic value can be referred simply as characteristic action. 3.1.21 conventional value of shares outstanding: arbitrated value for exceptional actions by consensus between the building owner and government authorities have an interest in it. 3.2 Symbols The symbols are used in this standard, regarding the steel structures and composite steelconcrete base is constituted by symbols (same size as the current text) and Symbols subscribed. The basic symbols used most frequently in this Standard are set out in 3.2.1 and 3.2.2 subscripts symbols in the same length plain text, to easy viewing. The general symbology is found established in this subsection and the more specific symbology some parts of this standard is presented in the relevant sections in order to simplify understanding and therefore the application of established concepts. 3.2.1 Symbols basis 3.2.1.1 Roman Lowercase the the the b bf bf bfc bs bw d db dF dh dp ds and f f CD

- Distance in general; distance between transverse stiffeners; region height compressed into slabs of composite beams; center to center distance between beams - Length of the openings - Width; effective width of the concrete screed - Effective width - Table width - Width of the pillar table; width of the compressed table - Width of stiffener - The nominal size of the fillet weld - Diameter in general; total height of the cross section; cylinder diameter - Diameter of the screw; outer diameter of the thread of threaded round bar - Distance from the upper surface of the concrete slab to the center of gravity of the area the effective formwork - Hole Diameter - Pin diameter - Distance from the center of gravity of the steel profile to the center of gravity armor - Eccentricity of loading - Voltage characteristic obtained by testing or resistant strain calculation - Calculation of the actual resistance to compression

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NBR 8800 - Based Text Revision - Characteristic compressive strength of concrete

f ckn fckb f ctm f dc f dt fr fu f ub f ucs fy f yF f ys fw g h hc hcs hf hF hthe hr ht kcs ks kv l lc ln lw n No ' nb ncs nE p qRd r r the r x, Ry s t tc tF

- Characteristic strength of the concrete density low-density normal compression to the compression - Average tensile strength of concrete - Voltage resistant compression calculation on the upper surface of the concrete slab - Voltage resistant traction calculation table at the bottom of the steel beam - Residual stress - Tensile strength of steel traction - Tensile strength of the bolt material or round bar threaded at traction - Tensile strength of steel connector - Yield strength of steel at normal stress - Yield strength of the steel pan - Yield strength of steel reinforcement - Minimum tensile strength of weld metal - Drilling template; acceleration of gravity - Overall height; Cell height; height of floor - Height of the concrete slab above the steel pan - Length of the pin after welding - Effective height - Rib height of steel formwork - Distance between the centroid of the tables; height of the openings - Height of the slab coating - Total height of the slab, including the concrete and formwork - Initial stiffness of the connectors - Initial stiffness of the bars of the armature; parameter associated tear between holes - Coefficient for shear buckling of the soul - Length overall; length unlocked laterally length cylinder; buckling length of the column - Clear distance, in the direction of the force, between the edge of the hole and the edge of the hole or adjacent the edge of the connected part - Length of action of the force in the longitudinal direction of the beam - Total length of the weld - Number of connectors - Number of connectors between the section with concentrated load and the adjacent section of zero moment - Number of screws - Number of shear connectors per rib - The ratio between the modulus of elasticity of steel and the elastic modulus concrete - Tax width of the screw - Calculating a resistance to shear connector - Radius of gyration; radius - Polar radius of gyration of the gross section in relation to the center of shear - Radii of gyration of the cross section with respect to x and y axes, respectively - Longitudinal spacing between two consecutive holes; minimum spacing between edges of openings - Overall thickness - Thickness of the concrete slab - Thickness of mold steel

Page 9 NBR 8800 - Based Text Revision tf t fc t fcs t

- Thickness of table - Thickness of the pillar table, thickness of the compressed table - The thickness of the board connector - Thickness of plate pulled

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tp s tw t toilets w xthe Y the yc y LNP yp ys yt

- Thickness of the stiffener - Web thickness - Web thickness of the connector - Size of the fillet leg strengthening or contour - Coordinates of the center of shear - Distance from the center of gravity of the compressed portion of the steel beam section to the upper surface of this beam - The neutral axis position - Distance from the neutral axis of the section laminated to the top surface of the steel beam - Distance from the center of gravity to the center of the steel shear beam - Distance from the center of gravity of the compressed portion of the steel beam section to the upper surface of this beam

3.2.1.2 Roman Uppercase The The the The ac The at The b The be The c The cs The and The f The F The f The fe The fg The fn The fnt The g The MB The n The s The sa The w Cb Cd C d' Cm Cpg Cred Ct

- General area - Cross-sectional area of the steel profile - Compressed area of the steel section profile - Pulled area of the steel section profile - Gross area of bolt - Resistant area or effective area of a bolt or threaded round bar - Cross-sectional area of the connected elements; cross-sectional area Concrete - Cross-sectional area of the connector - Effective net cross-sectional area - Effective area - Area of mold steel - Area of the table - Effective area of table pulled - Floor area of tensioned or compressed table - Net area of tensioned or compressed table - Net area of the pulled table - Gross cross-sectional area - Theoretical area of the face melting - Net area - Total transverse reinforcement area per unit length, including additional equipment and any equipment provided to bending of the slab; area cross section of the longitudinal reinforcement - Area of additional armor - Effective area of shear; effective area of the weld; area of the soul - Modification factor for bending moment diagram nonuniform - Resistance calculation of the compressed thickness of the concrete slab - Resistance calculation of the compressed portion of the steel profile - Equivalence of moments - Coefficient used in the calculation of slender beams - Reduction factor of the strength of the shear pin type connector with head - Reduction coefficient used in the calculation of the effective net area

Page 10 10 Cv Cw D Dthe E

NBR 8800 - Based Text Revision - Coefficient of shear - Constant warping of the cross section - Outer diameter of tubular circular section; OD eyelet head - Diameter of apertures - The tangent modulus of elasticity of steel

Ec

- Initial secant modulus of elasticity of concrete at the limit of resistance compression - Modulus of elasticity of concrete reduced due to the effects of shrinkage and creep - Initial secant modulus of elasticity of the concrete in the low density limit Compressive strength - Secant modulus of elasticity at normal density concrete limit compressive strength - Tangent modulus of elasticity of steel reinforcement of concrete - Characteristic value of permanent actions - Characteristic value of variable actions - Characteristic value of the outstanding shares - Modulus of transverse elasticity of steel, equal to 0.385 E; characteristic action permanent; center of gravity of the bar - Moment of inertia - Moment of inertia of the cross section of the steel profile - Moment of inertia of the cross section of the concrete - Moment of inertia effective - Moment of inertia of the pillar - Moment of inertia of the cross section of the reinforcement of concrete - Moment of inertia of uniform twisting of the steel section - Moment of inertia of the homogenized composite section - Moment of inertia of the beam - Moments of inertia of the cross section with respect to x and y axes, respectively - Buckling coefficient used in sizing bars compressed - Or length will generally - Distance between the sections of maximum positive and negative moments - Length unlocked - Length of the U profile connector - Length of the stretch of positive moment; distance between points zero moment - Will theorist steel pan toward the ribs - Height of the floor for a pillar - Shear span - Length of the input strength of concrete - The beam will - Bending moment - Resistant bending moment calculation of steel girder isolated - Bending moment of elastic buckling - Bending moment plasticizing section - Bending moment corresponding to the onset of flow - Resistant bending moment calculation - Bending moment resistant plasticizing calculation

E 'c Ecb Ecn Es FG FQ FQ, exc G I I the Ic If Ip Is IT I tr Iv I x, Ry K L L' Lb Lcs Land LF Lp Ls Lt Lv M M the M cr Mp l Mr M Rd M Rd, p l

Page 11 NBR 8800 - Based Text Revision M Rd ;xM Rd, y M Rk MRd MRd,dist M-

;M-

- Resistant to bending moments calculated respectively around the axes x ey cross section - Characteristic bending moment resistant - Resistant bending moment calculation in the region of negative moment - Resistant bending moment calculation in the region of negative moment, for limit state of lateral buckling Distorted - Resistant bending moments for calculating the left and right ends,

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Rd,esq

Rd,dirrespectively, module of composite beams subjected to negative moment in case of continuous beams, or mixed connections in the case of semicontinuous beams

M- Bending moment resistant characteristic in the region of negative moment Rk M Sd - Bending moment calculation requestor M Sd, ;GM' Sd, G - Applicants bending moments calculation due to active actions respectively before and after the strength of concrete reaches f 0.75 ck M Sd, max - Maximum bending moment calculation requesting the bar, determined by the analysis of the first order M Sd, q - Bending moment calculation in requesting biapoiada beam function of the abscissa x M Sd,; xM Sd, y - Requesting bending moments of calculation respectively about axes x and y of the cross section N - Length of action of the force in the longitudinal direction of the beam, the number of cycles of variation of tension during the useful life of the structure Nc, R - Normal force resistant compression calculation Nand - Normal force of elastic buckling Np - Normal force corresponding to the flow cross section l NRd - Tough normal force calculation NRd, p - Tough normal force calculation of the cross section to the total lamination l NSd - Normal force requestor compression calculation Nt, Rd - Normal force resistant traction calculation Ny - Normal force corresponding to the flow of the compression section effective cross P - Thread pitch Pdub - Calculating a resistance screw, taking into account the shear and contact pressure in the holes PSRD - Calculation of resistance of the armature bars Q - Variable action; coefficient of local buckling; additional traction force caused by the leverage Qthe ; Qs - Coefficients that take into account the local buckling of AA and AL elements, respectively QRd - Sum of the individual resistance calculation, q Rd, The connectors shear section located between the maximum positive moment and the section adjacent zero moment Q Rd ' - Sum of the individual resistance calculation, q Rd, The connectors shear located between sections of maximum positive and negative moments R - Fillet radius between the head and the body of the lug Rd - Resistance calculation RFIL - Reduction factor for joints up only a couple of fillet weld transverse RPJP - Reduction factor for welds notch partial penetration RRd - Resistant request calculation RRk - Resistant feature request Sd - Request for calculation

Page 12 12 Tb Td TRds TSd Vp l VRd VRd l VRd, p V

NBR 8800 - Based Text Revision - Minimum strength prestressing screw - Calculation of resistance region pulled the steel profile - Sturdy traction force calculation in the longitudinal reinforcement bars - Requesting traction force calculation on the screw without leverage - Shear force corresponding to yielding of the soul shear - Resistant shear force calculation - Sturdy longitudinal shear force calculation of composite slabs - Resistant shear force calculation to puncture caused by a load concentrated - Sturdy vertical shear force calculation of composite slabs

VRd, Rk v VRkt VSd VSd, q W W the W c, W t Wf W tr W x, W y Zpa Zpc Zps

- Shear resistant feature - Shear resistant characteristics including the effect of field drift - Shear strength calculation requestor - Shear strength calculation in requesting biapoiada beam function of the abscissa x - Minimum modulus of section of elastic strength relative to bending axis - Resistance of the elastic modulus of the steel section profile - Elastic modulus of resistance of the tablet and pulled next to the section, respectively, relative to the bending axis - Effective elastic modulus of resistance - Modulus of the homogenized elastic resistance section in composite beams - Elastic resistance modules with respect to x and y axes, respectively - Module plastic resistance of the steel profile section - Module plastic resistance of the concrete section - Module plastic resistance of the armature of the concrete section

3.2.1.3 Greek Lowercase α β β the β cn β vm δ ε cs ε smu ε su ε sy φ γ γ the γ c γ cb γ cn γ cna γ cs γ g γ q γ r

- Related to sizing the compression curve coefficient; coefficient related to the effect Rüsch - Reduction factor - Coefficient of thermal expansion of steel - Coefficient of thermal expansion of the normal density concrete - Coefficient which takes into account the rotation capacity required for connection - Contributor steel, scroll, arrow - Specific deformation of free shrinkage of concrete - Deformation of the concrete armor involved - Strain corresponding to the tensile strength of the armor isolated - Strain corresponding to the yield strength of the armor isolated - Diameter of the reinforcement bars - Weighting coefficient of resistance - Specific weight of steel; weighting the strength of steel - Specific weight of concrete; weighting the resistance of the concrete - Specific weight of the concrete of low density - Specific weight of concrete normal density unarmored - Specific weight of normal density concrete with reinforcement - Weighting coefficient of resistance of the connector - Weighting of permanent actions - Weighting of variables shares - Weighting coefficient of stiffness

Page 13 NBR 8800 - Based Text Revision γ s γ z λ λ the λ p λ r λ rel μ ν the ν cn ν cb ρ

- Weighting the strength of steel armor - Coefficient for setting the order of magnitude of the horizontal displacements - Slenderness parameter - Reduced slenderness ratio - Slenderness parameter corresponding to the lamination - Slenderness parameter corresponding to the onset of yield - Relative slenderness - Average coefficient of friction - Poisson's ratio of structural steel - Poisson's ratio of concrete normal density - Poisson's ratio of concrete of low density

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ρ dist σ σ cr σ c, R σ and σ Rd σ Sd σ SR σ TH τ Rk ψ oj ψ ;ψ 1j 2j

associated with the distortion compressive strength - Reduction factor for lateral buckling of the cross section with - Tension in general - Tension buckling - Tension buckling - Critical elastic buckling stress - Resistant strain calculation - Requesting tension calculation - Permissible limit for the range of variation of stresses - Permissible limit of range of voltages, for an infinite number of request cycles - Voltage characteristic shear - Factor combination of variable actions - Utilization factors of

3.2.1.4 Greek Uppercase Δu s Δu i Σ

- Deformation capacity of the armature bars - Deformation capacity of the connection - SUM

3.2.2 Symbols subscribed 3.2.2.1 Roman Lowercase the b c cb cn cs d and f f g i n

- Steel - Screw; threaded round bar - Concrete; compression - Low density concrete - Normal density concrete - Shear connector - Calculation - Elastic - Effective - Table - Gross - Order number - Net

Page 14 14 pl s t u w x y

NBR 8800 - Based Text Revision - Lamination - Armor - Traction - Break - Soul; solder - On the x-axis - Runoff; relative to the y axis

3.2.2.2 Roman Uppercase F Rd Rk Sd

- Mold steel - Resistant calculation - Resistant characteristic - Requesting calculation

3.3 Units Most of the expressions presented in this standard is dimensionless, so they should be employed quantities with consistent units. When units are mentioned, they are according to the International System of Units. 4 General conditions of project 4.1 General 4.1.1 The fully or partially executed works with steel frame or mixed structure steel-concrete must comply with elaborate design in accordance with this standard, under responsibility of a legally qualified professional with experience in design and construction these structures, which must be manufactured and constructed by competent companies and keep running under competent supervision. 4.1.2 It is understood as the set of design calculations, drawings, specifications and manufacturing Mounting structure. 4.2 Design drawings 4.2.1 The design drawings must be executed in an appropriate scale for the level of desired information. Should contain all the necessary data for the detailed structure for the implementation of assembly drawings and the design of foundations. 4.2.2 The design drawings shall indicate which standards were used and give specifications for all structural materials used. 4.2.3 In addition to the materials, data must be reported to the actions of calculation adopted and calculation of internal forces to be resisted by bars and links, when required to proper preparation of fabrication drawings. 4.2.4 For connections with high strength bolts, the design drawings shall indicate whether the tightening will be normal or initial prestressing, and in the latter case, if the bolts to work shear, if the connection is friction or contact.

Page 15 NBR 8800 - Based Text Revision 4.2.5 Welded connections should be characterized by appropriate symbology containing to complete its execution information in accordance with AWS A2.4. 4.2.6 In the case of industrial buildings, shall be made ​ on the design drawings schema location of the most important actions resulting from equipment that will be supported by the structure, the values ​ of these actions and, eventually, the data for consideration dynamic effects. 4.2.7 Where necessary, the conditions should be considered for installation and indicated provided lifting points and weights of the parts of the structure. Should be taken into account coefficients appropriate for the type of equipment to be used in assembling impact. In addition, must be given the positions that are temporarily occupied by main or auxiliary equipment mounting on the structure, mooring position cables or spies, etc.. Other situations that may affect the safety of the structure should also be considered. 4.2.8 In cases where the lengths of the frame pieces may be influenced by

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temperature variations during assembly, must be given the variation ranges considered. 4.2.9 should be indicated in the design drawings of the contraflechas beams soul filled and lattice. 4.3 Drawings manufacturing 4.3.1 The fabrication drawings should translate faithfully to the factory, the information contained in the design drawings, giving complete information to manufacture all Component elements of the structure, including materials and specifications, lease, type and size of all bolts, welds factory and field. 4.3.2 Where necessary, it should be indicated on the drawings the execution sequence of links important to avoid the appearance of excessive residual stresses or warping. 4.4 Assembly drawings The assembly drawings shall indicate the main dimensions of the structure, brand of parts, dimensions of bars (when required for approval), elevations of lower faces of plates base pillars, all dimensions for detail placement of anchors and other information necessary for the assembly of the structure. Should be clearly indicated all permanent elements or essential to the integrity of the temporary structure partially Built. Also applies here to the provisions in 4.3.2. 4.5 Materials 4.5.1 Introduction 4.5.1.1 The structural steel and metal materials approved for use by this connection Standard 4.5.2 and are cited in the concrete and steel for armor in 4.5.3. 4.5.1.2 Full details of the materials listed in 4.5.2 and 4.5.3 are the corresponding specifications and more information on the structural steels and materials metal binding are in Annex A.

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NBR 8800 - Based Text Revision

4.5.2 Structural Steels and metal bonding materials 4.5.2 Steels 1 for profiles, rods and plates 4.5.2.1.1 steels approved for use in this standard for profiles, rods and plates are those with structural qualification ensured by Brazilian standard specification or standard or foreign, provided they have characteristic resistance maximum flow 450 MPa and relationship between resistance characteristics to rupture and drain not less than 1.18. 4.5.2.1.2 is still allows the use of other structural steels since they have resistance feature to the maximum flow 450 MPa, the relationship between resistance characteristics rupture and drain not less than 1.25 and that the responsibility for the project to analyze the differences between these grades and specifications mentioned in 4.5.2.1.1 and mainly the differences between the sampling methods used in determining its properties mechanical. 4.5.2.1.3 It is recommended not to use structural steels without qualification. However, this is tolerated use, provided free of surface imperfections, only minor parts and details

importance, where the properties of steel and its weldability not affect the resistance of structure. If this type of steel is used, should not be adopted in the project higher values 180 MPa and 300 MPa for the characteristic flow resistance and resistance feature at break, respectively. 4.5.2.2 Steel castings and forgings Where the use of fabricated structural elements with molten steel is necessary or wrought Brazilian standards related to the issue or standard or must be obeyed foreign specification. 4.5.2.3 Bolts The screw steel low carbon must meet ASTM A307 or ISO 898 Class 4.6, the high-strength bolts, including nuts and washers appropriate hardened, shall comply with ASTM A325, ASTM A325M or ISO 898 Class 8.8 and screws alloy steel hardened and tempered shall meet ASTM A490, ASTM A490M or 898 ISO Class 10.9. 4.5.2.4 Electrodes, welding wire and flux 4.5.2.4.1 The electrodes, wires and fluxes for welding shall meet the following Specifications: a) for mild steel electrodes, coated, for electric arc-welding: AWS A5.1; b) electrodes for low alloy steel, coated, for electric arc-welding: AWS A5.5; c) for bare mild steel electrodes and flux for submerged arc welding: AWS A5.17; d) for mild steel electrodes for electric arc welding with shielding gas: AWS A5.18;

Page 17 NBR 8800 - Based Text Revision e) for mild steel electrodes for arc welding with flux in the core: AWS A5.20; f) to bare steel electrodes, low alloy and flux for submerged arc welding: AWS A5.23; g) for low alloy electrodes for arc welding with shielding gas: AWS A5.28; h) for low alloy electrodes for arc welding with flux in the core: AWS A5.29. 4.5.2.4.2 Approval of specifications for electrodes cited in 4.5.2.4.1 is taken regardless of the requirements for impact tests which in most cases are not required for buildings. 4.5.2.5 Shear Connectors 4.5.2.5.1 The pin type connectors steel with heads shall meet the requirements of Chapter 7 of AWS D1.1: 2002. 4.5.2.5.2 The steel shear connectors in the profile laminate U must comply with 4.5.2.1.

17

4.5.2.5.3 The steel shear connectors C profile cold-formed must obey requirements of ISO 14762. 4.5.2.6 Steel mold of the slab The steel mold of the slab and its coat must comply with Section S.7 (Annex S). 4.5.2.7 Identification The materials and products used in the structure must be identified by their specification, including type or grade, if applicable, using the following methods: a) quality certificates provided by plants or producers duly related to the products supplied; b) legible markings applied to the material by the producer, in accordance with the standards of corresponding standards. 4.5.2.8 General Mechanical properties For calculation purposes should be adopted for steels listed, the following values Mechanical properties: a) tangent modulus,

E = 205000 MPa ; ν =03; the

b) Poisson's ratio,

β = 12 ×10 - 6 ° C - 1; the

c) coefficient of thermal expansion,

Page 18 18

NBR 8800 - Based Text Revision d) specific weight,

γ = 77 kN / m 3 . the

4.5.3 Concrete and steel reinforcement 4.5.3.1 The properties of normal density concrete should conform to NBR 6118. So the characteristic compressive strength of concrete of this type should be between 10 MPa and 50 MPa, and the following values ​ should be used: a) initial secant modulus of elasticity in compression yield strength, E = 4760 f , Where E cn f ckn are given in megapascals (f cn ckn characteristic of normal density concrete compressive); ν

b) Poisson's ratio,

= 020 ;

cn

c) coefficient of thermal expansion, d) specific weight, reinforced concrete.

γ

cn

ckn is the resistance

β

cn

= 10 - 5 °C - 1;

= 24 kN / m 3 in concrete without armor and

γ

cna

= 25 kN / m 3 on

4.5.3.2 The properties of low density concrete must comply with standard or relevant domestic or foreign specifications. This type of concrete should have specific weight

at least 15 kN / m 3 unarmored, and the modulus of elasticity in the initial drying limit compression strength in megapascals should be taken equal to: E

cb

= 40 5,γ 15, f cb ckb

where: γ is the specific weight of the concrete of low density, without reinforcement in a quilonewton cb cubic meter; f ckb is the characteristic strength of the concrete low-density compression in megapascals. For Poisson's ratio, can be used value of 0.2 (equal to the density of the concrete normal). The thermal expansion coefficient must be determined by specific study. 4.5.3.3 this standard, the secant modulus of elasticity, compressive strength characteristic, Poisson's ratio, thermal expansion coefficient and the specific weight of the concrete will be always represented by E cF ck, Ν c, Β c and cγ, Respectively. So if the concrete is of γ =γ Normal density must be taken E =E f, = f , ν = ν , β = β and on c cn ck ckn c cn c cn c cn concrete without reinforcement orγ = γ for reinforced concrete; and if low density c cna γ = γ for the concrete without reinforcement orγ = γ E =E f, = f , ν = ν , β = β and c cb ck ckb c cb c cb c cb c cba for reinforced concrete. 4.5.3.4 The properties of steel reinforcement shall conform to NBR 6118.

Page 19 NBR 8800 - Based Text Revision

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4.6 Basis for sizing The method of states limits used for sizing the components of a structure requires that no applicable limit state is exceeded when the structure is subject to all appropriate combinations of actions. When the structure no longer meets objectives for which it was designed, one or more states limit has been exceeded. The states ultimate limits are related to the safety of the structure subject to more combinations unfavorable actions of calculation provided for in the lifetime, in a transient situation or When acting exceptional action. The limit states are related performance of the structure under normal service conditions. 1 4.6 Dimensioning for ultimate limit states 4.6.1.1 The design for the ultimate limit states implies that the request Tough for calculating each component or assembly of the structure equal to or greater than the active calculation request. In some situations, it is necessary to combine through expressions of appropriate interaction terms reflecting relations between active requests calculation and resistant requests from different calculation. Each sturdy request calculation, S is calculated for the applicable limit state and is equal to the quotient of the sturdy request characteristic S RkAnd the weighting coefficient γ of resistance. Resistant requests S characteristics Rkand the coefficient γ of resistance are given in sections 5, 6, 7 and 8, depending ultimate limit state. Other security-related checks are in Section 9. 4.6.1.2 The calculation of active request must be determined for combinations of actions calculation that are applicable, in accordance with 4.7.

Rd,

4.6.2 Scaling to limit states The structure should be checked for serviceability limit states in accordance with the requirements Section 11. 4.7 Actions and combinations of actions 4.7.1 Values ​ and classification The actions to be taken in the design of structures and their components are set by Brazilian standards NBR 6120, NBR NBR 6123 and 7188, or other applicable standards, and also in Annex B of this Standard. According to NBR 8681, these shares are classified according to their variability in time, in the following three categories: - F G: Permanent actions - actions resulting from the own weight of the structure and all Component elements of the building (floors, tiles, permanent walls, coatings and finishes, fixed equipment, etc..), which are called actions Direct permanent, and actions from effects of support settlements, retraction materials and prestressing, which are called indirect permanent actions; - F QVarying actions - actions resulting from the use and occupation of the building (due to actions overloads on floors and roofs, equipment and movable partitions, etc..), pressure hydrostatic, buoyancy of earth, wind, temperature variation, etc..; - F Q, exc : Exceptional actions - actions resulting from fires, explosions, shocks vehicles, seismic effects, etc..

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NBR 8800 - Based Text Revision

In the rules of combinations of actions for ultimate limit states and use, given 4.7.2 and 4.7.3 respectively, actions must be taken with their characteristic values according to NBR 8681. Exceptional actions can be taken to their values exceptional standard. 4.7.2 Combinations of actions for ultimate limit states 4.7.2.1 Combinations of actions for ultimate limit states, according to NBR 8681, are: a) normal combinations latest: Σm ( γ F ) + γ F + Σn ( γ ψ F ) gi Gi 1qQ1 qj oj Qj i=1 j=2 b) past or special construction (temporary situation) combinations: Σm ( γ F ) + γ F + Σn ( γ ψ F ) gi Gi 1qQ1 qj oj,f Qj = = i1 j2 c) exceptional recent combinations, except for the case where the outstanding action Fire follows (see 4.7.2.2): n Σm ( γ F ) + F + Σ (γ ψ F ) gi Gi Q,exc qj oj,f Qj

i=1

j=1

Where: FGi are the permanent actions; FQ1 variable is considered as the main action in the normal combinations, or as leading to transient situation in special combinations or building; FQjother variables are the shares; FQ, exc is the exceptional action; γ are the weighting coefficients of permanent actions, provided in Table 1 (for gi further information should be consulted to NBR 8681); γ are the weighting coefficients of the variables shares, provided in Table 1 (for qj further information should be consulted to NBR 8681); ψ factors are the combination of variables that can act concomitantly actions oj with the main variable action F Q1Under normal combinations, as shown in Table 2; ψ j, f factors are effective combination of live loads that may act concurrently with the main variable action F During the transitional situation, or Q1 with exceptional action F . The factor ψ factor is equal to ψ oj adopted in combinations Q, exc j, f

Page 21 NBR 8800 - Based Text Revision normal except when the main action F very small role, in which case ψ (Table 2).

21

have a time Q1or exceptional action F Q, exc may be taken equal to the corresponding ψ j, f

2

Table 1 - Weighting coefficients actions

Combinations

Normal Special or Construction Exceptional

Own weight structures metal

Weight own structures premolded

1.25 (1.00) 1.15 (1.00) 1.10 (1.00)

1.30 (1.00) 1.20 (1.00) 1.15 (1.00)

Effect of temperature 2)

Permanent actions (γ g) 1) 3) Direct Own weight of Own weight of structures elements molded in constructive site and industrialized elements with additions "in constructive loco " industrialized 1.35 1.40 (1.00) (1.00) 1.25 1.30 (1.00) (1.00) 1.15 1.20 (1.00) (1.00) Shares variables (γq) 1) 4) Wind action

Own weight elements Indirect constructive and in general equipment 1.50 (1.00) 1.40 (1.00) 1.30 (1.00)

1.20 (0) 1.20 (0) 0 (0)

Other variables actions including those arising the use and occupation

Normal

1.20

1.40

1.50

Special or Construction

1.00

1.20

1.30

Exceptional 1.00 1.00 1.00 NOTES: 1)The values ​ in parentheses correspond to the coefficients for permanent actions favorable to safety; variables and exceptional actions favorable safety should not be included in the combinations. 2)The temperature effect mentioned does not include the generated equipment, which must be regarded as action resulting from the use and occupancy of the building. 3)Direct permanent actions that are not conducive to security may optionally be considered all grouped with weighting equal to 1.35 when the stock variables arising from the use and occupation is equal to or greater than 5 kN / m2Or 1.40 when it is not. 4)If the direct permanent actions that are not conducive to safety are grouped variables actions that do not are favorable safety can optionally also be considered all grouped with coefficient equal weighting of 1.40 when the variables arising from the use and occupation shares are equal to or greater than 5 2Or 1.50 when it is not (even in this case, the temperature effect can be seen kN / m separately, with its own weighting). 4.7.2.2 Combinations of exceptional past actions to ultimate limit states in fire situation should be determined according to NBR 14323. 4.7.3 Combinations of actions for serviceability limit states In the combinations of actions for serviceability limit states are considered all actions permanent, including permanent deformation imposed, and the actions variables corresponding to each of the types of combinations as follows:

Page 22 22

NBR 8800 - Based Text Revision a) quasi-permanent combinations of use (combinations that may act during much of the lifetime of the structure, the order of half of that period): Σm F + Σn (ψ F ) Gi j2Qj i=1 j=1 b) frequent use combinations (combinations that repeat often 5 times 50, or having during the lifetime of the structure, of the order of 10 total duration equal to a not insignificant part of that period, of the order of 5%): Σm F + ψ F + Σn (ψ F ) Gi 1 Q1 j2Qj i=1 j=2 c) use of rare combinations (combinations that can act at most a few time during the life of the structure):

Where:

Σm F + F + Σn (ψ F ) Gi Q1 j1Qj i=1 j=2

FGi are the permanent actions; FQ1is the main variable action of the combination; ψ F are the common values ​ of the action; 1j Qj ψ F are the quasi-permanent values ​ of the action; 2j Qj ψ , Ψ factors are used as table 2. 1j 2j

Table 2 - Factors combo and use factors Share

ψ 1) oj 0.6 0.6

ψ

1j 0.5 0.3

ψ

2j Uniform temperature variations compared to the local average annual 0.3 Dynamic pressure of the wind on structures in general 0 Actions resulting from the use and occupation: - No predominance of equipment that remain fixed for long periods of time or high concentrations of persons 0.5 0.4 0.3 - With predominance of equipment that remain fixed for long periods of time or high concentrations of persons 0.7 0.6 0.4 - Libraries, archives, warehouses, workshops and garages 0.8 0.7 0.6 Moving loads and their dynamic effects: - Beams bearing crane 1.0 0.8 0.5 - Pedestrian Walkways 0.6 0.4 0.3 Note: 1)The coefficients ψ must be accepted as 1.0 shares for variables of the same nature of the variable action oj main F Q1 .

Page 23 NBR 8800 - Based Text Revision 4.7.4 Cases not covered in this Standard For cases of combinations of actions related to the ultimate limit states or use not covered in this standard shall be in compliance with the requirements of ISO 8681. 4.8 Stability and structural analysis 4.8.1 General 4.8.1.1 This subsection deals with the analysis and stability of structures. Thus, 4.8.2 are defined braced and not braced structures and provided guidelines for assessment their stability, and 4.8.3, general rules are presented for structural analysis for verification of ultimate limit states. 4.8.1.2 Structural analysis for verification of limit states must be ugly as stipulated in this standard parts dealing with the issue. If analysis is done second order, should follow the procedures given in 4.8.3, but using the combinations of actions appropriate for these types of limit states. 4.8.2 Structural Stability 4.8.2.1 General The stability of the structure as a whole and must be guaranteed for each component element, considering the significant actions of the deformed structure effects. 4.8.2.2 braced structures 4.8.2.2.1 In those trusses and structures whose lateral stability is guaranteed by system suitable bracing, shear walls structural or other means equivalents, here classified as braced structures, the buckling coefficient K to be used in the design of compressed bars, provided the requirements of 4.8.5, can be taken equal to 1.0 unless it is demonstrated by the analysis of the structure, or

23

if applicable, by the use of attachments H and J, which values ​ less than 1.0 may be used. Case there is a rigid connection between beams and columns, reducing the stiffness adjustments of pillars requested outside elastic allowed. 4.8.2.2.2 A second-order analysis that includes the initial imperfections of the structure, as 4.8.3, can be used in place of the requirements presented in 4.8.5. 4.8.2.2.3 vertical bracing system must be determined by structural analysis and be adequate to prevent buckling and maintain the stability of the structure, including resisting the destabilizing effects of gravity loads on pillars and other structural components vertical unable to withstand lateral forces, combinations of shares for calculation stipulated in 4.7. 4.8.2.2.4 Lets consider that the internal and external structural walls and slabs and floor covering part of the vertical bracing system provided appropriately sized and connected to the structure. Columns, beams and diagonal when used as part of the vertical bracing system can be considered as bars a vertical trellis swing study of buckling and lateral stability of the structure.

Page 24 24

NBR 8800 - Based Text Revision

The axial deformation of all the bars of the vertical bracing system must be included the study of lateral stability. 4.8.2.3 Structures not braced 4.8.2.3.1 In structures where the lateral stability depends on the flexural rigidity of beams and columns rigidly connected to each other, here classified as not braced structures, the coefficient K buckling of compressed bars should be determined by structural analysis or, if applicable, as Annex J. The destabilizing effects of gravity loads on pillars and other vertical structural members without ability to withstand horizontal forces should be considered in the analysis. Adjustments reducing the stiffness of pillars requested outside elastic allowed. 4.8.2.3.2 If analysis of the structure is taken directly into account the effects of initial imperfections of the structure as a whole, as 4.8.4.1, 4.8.4.2 and 4.8.4.3 can be consider the buckling coefficient K equal to 1.0. 4.8.2.3.3 In determining the effects of the strength of the instability should be included structural and axial deformation of the pillars, combinations of shares for calculating stipulated in 4.7. 4.8.3 Structural Analysis 4.8.3.1 Types of analysis and second order effects 4.8.3.1.1 The internal forces calculation in bars and links the structure to check the ultimate limit states, must be obtained through elastic analysis, as 4.8.3.1.2, except when permissions for other types of analysis are explained in parts of this Standard. 4.8.3.1.2 Elastic second-order analysis must be rigorous, as 4.8.3.1.3, for combinations appropriate actions listed in 4.7. Still admits the use of elastic analysis estimated and approximate second order, described in 4.8.3.3 and 4.8.3.4 respectively, depending on the sensitivity of the structure to horizontal displacements (see 4.8.3.2) and since the conditions shown are met. In any analysis must take into account the effects of initial imperfections of the structure as a whole, according to

4.8.4. 4.8.3.1.3 The term rigorous elastic second-order analysis that in which the equations equilibrium is established in the deformed configuration of the structure. This type of analysis usually has a high degree of complexity, requiring a strategy of numerical resolution involving iterative procedures, and allows properly account the overall effects and local second order, defined in 4.8.3.1.4 and 4.8.3.1.5 respectively. Its validity in However, it is limited in principle to cases in which the second order effects do not exceed 40% analysis of the first order. If this occurs, we must increase the rigidity of the structure to reduce the horizontal displacements, or place an elastoplastic analysis of second order, the unless it is demonstrated that the stresses acting, with the combinations of actions of calculation, as 4.7, even if including the residual stresses do not exceed the yield strength steel in any cross section. 4.8.3.1.4 Submitted to vertical and horizontal forces, structures moving horizontally. Global second order effects, also called P-Δ effects are the answers

Page 25 NBR 8800 - Based Text Revision arising from horizontal displacements on the ends of the bars (rotations of ropes), which are obtained by establishing equilibrium in the deformed configuration structure represented by the polygon defined by the strings of the various bars. 4.8.3.1.5 The local second order effects, also called P-δ effects are the answers resulting displacement of the deformed configuration of the structure of each bar subject to the normal force in relation to the position of the respective string. 4.8.3.2 Structures little too sensitive to horizontal displacements 4.8.3.2.1 The structure is considered to be very sensitive to horizontal displacements are, in all their floors, the coefficient B 2Given by the following expression, not exceed 1.1: B = 2

1 1-

Σ N Sd oh h Σ H Sd

Δ

Where: Σ N

is the sum of the normal forces applicants calculation across all pillars and Sd resistant to vertical loads other elements (including the pillars and other elements that not belong to the system resistant to horizontal forces), considered on the floor; Δ is the horizontal relative displacement (between floors); oh Σ H is the sum of all horizontal forces producing displacement calculation Sd horizontal on the floor considered; h is the height from the floor (wheelbase beams). 4.8.3.2.2 The structure is considered very sensitive to horizontal displacements are in the least one of his stories, the coefficient B 2 is greater than 1.1. 4.8.3.3 Analysis estimated second order 4.8.3.3.1 The rigorous elastic second-order analysis, depending on the sensitivity of the structure

25

the horizontal displacements can be replaced by an analysis taking into account the effects of initial imperfections in accordance withestimated, 4.8.4, with the following rules: - Insensitive to the horizontal displacements global structures for secondary order can be neglected and the local second-order effects should be considered a simplified form as 4.8.3.3.2; - In very sensitive to horizontal displacements structures with the highest coefficient B taking all floors not exceeding 1.3, the second global and local effects order can be considered a simplified form as 4.8.3.3.3.

2,

4.8.3.3.2 In some structures sensitive to horizontal displacements, the bending moment requestor calculation, M SdIncluding the local second-order effects, can be determined by:

Page 26 26

NBR 8800 - Based Text Revision M= Sd

B M 0 Sd1

Where: B0 is a coefficient given by: C m ≥ 1 If the requester normal force calculation on the bar, N N 1 - Sd N and compression; B = 0

B = 1If the normal force on the bar requesting calculation, N 0

Sd, Is the

Sd, For traction.

N is the normal force of elastic buckling of the bar in the plane considered, calculated and based on their buckling length, according to 4.8.2; Cm is an equivalence of moments, given by: - If no transverse forces between the ends of the bar in the plane bending: C

m

= 060 - 040

M M

1 2

being M M the ratio between the smallest and the largest bending moments of 1 2 applicants in calculating the bending plane, the supported ends of the bar, taken as positive when the curvature and moments cause reverse cause negative when a single curve; - If lateral forces between the ends of the bar in the plane bending, the value of Cm should be determined by rational analysis or be taken in the case of 0.85 bar with both ends embedded and 1.0 in other cases. M Sd 1requestor is the bending moment calculation at bar, obtained by structural analysis elastic first order.

The other internal forces to be used in the verification of ultimate limit states can be those obtained directly by first-order elastic analysis. 4.8.3.3.3 In very sensitive to horizontal displacements structures with the highest coefficient B not more than 1.3, a simplified solution for the assessment of the overall effect of second order consists in determining the internal forces based on elastic analysis first order, multiplying the actions that cause horizontal displacements of the found by combining 0.95 times higher B obtained for normal forces and 2. The values ​ cutting shall be used in the verification of ultimate limit states, but additionally the requestor bending moment calculation to be used must also include the local effects of second order, is given by:

2

Page 27 NBR 8800 - Based Text Revision M= Sd

27

B M 0 Sd2

Where: B0 should be determined as 4.8.3.3.2; M Sd, requestor is the bending moment calculation obtained from the above analysis. 2 4.8.3.3.4 In very sensitive to horizontal displacements structures with the highest coefficient B greater than 1.3, considering all the floors, the only option allowed in place of the analysis elastic rigorous second order is the use of the approximate analysis described in 4.8.3.4.

2

4.8.3.4 Analysis approximate second order 4.8.3.4.1 Annex V procedures are presented to approximate elastic analysis second order, which can be used for any larger value of the coefficient B considering all floors of the structure, even when it exceeds 1.3, and that generally provide more accurate results than those obtained by the analysis described in estimated 4.8.3.3. 4.8.3.4.2 Other procedures for approximate elastic second-order analysis can be used provided they lead to accurate results equivalent to the procedures of Annex V. 4.8.4 Consideration of initial imperfections of the structure as a whole 4.8.4.1 The effect of initial imperfections of the structure as a whole may be taken into account directly in the analysis by considering an equivalent geometric imperfection in form of an initial displacement between floors 200 h , Where h floor height (distance wheelbase beams), accumulated over the height of the building. It is also admitted consider it through the simplified procedure of notional forces given in 4.8.4.2. 4.8.4.2 The effect of initial imperfections of the structure can be taken into account by application on each floor of the structure, a fictitious horizontal force called Force notional, taken equal to 0.5% of the sum of normal forces applicants calculation in all pillars and other elements resistant to vertical loads, considered on the floor. This force notional should be considered acting in all combinations of shares used for calculating the calculation of the structure. However, to avoid an overly conservative condition, allows himself not consider it in combinations that work forces due to wind, ie can consider it only for the combination of actions that act only in calculating actions Direct permanent and result from the use and occupation of the building (see 4.7.2.1). It is not necessary to consider them in the calculation of the horizontal support reactions.

2,

4.8.4.3 The effect of initial imperfections is to be applied in all horizontal directions relevant, but only one at a time (considering both directions). The possible torsional effects must also be considered. 4.8.4.4 Allows the analysis of the structure without directly considering the effect of imperfections initials, if the requirements of 4.8.2.2.1 are met for braced structures and 4.8.2.3.1 for non-braced structures.

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NBR 8800 - Based Text Revision

4.8.5 Strength and stiffness of containments 4.8.5.1 General 4.8.5.1.1 The following requirements relate to minimum resistance and stiffness that side retainers must have in order to be effective, so that, for example, bars compressed can be calculated considering the buckling length equal to the distance between the points at which these contentions are present. One should strive to put perpendicular to the bar retainers; resistance (force or moment) and stiffness (force per displacement unit time or per unit of rotation) sloping or containments diagonals should be adjusted to the angle of inclination. The evaluation of the rigidity provided the retainers must include its dimensions and geometric properties as well as the effects links and anchor details. 4.8.5.1.2 Two types of containment, relative and nodal are considered. The restraint on controlling the motion of a point contained in contained relation to adjacent points, while Specifically containing the nodal point movement control contained no interaction contained with the adjacent points (1 illustrates the two types of restraint bars compressed and flexed). The strength and stiffness provided by the stability analysis of restraint should not be less than the required limits. N

N

N

N

h Sum Diagonal N

N Relative

N

N Nodal

a) Containment in compressed bars

Relative

Nodal

b) Containment flexed in bars Figure 1 - Types of containment 4.8.5.2 Floors with diagonal bracing panels or In structures in which the lateral stability is ensured by diagonal bracing, shear walls or equivalent means, the tensile shear strength and

Page 29 NBR 8800 - Based Text Revision stiffness necessary for stability of these systems on each floor, are given, respectively, by: P β

br br

= 0004 Σ N =

Sd

2γ ΣN r Sd h

Where: γ is the weighting coefficient of rigidity equal to 1.35; r ΣN is the sum of the normal forces requesters calculate the pillars and other Sd resistant elements to vertical forces considered the floor; h is the height from the floor, making wheelbase beams. These stability requirements should be combined with those related to forces and Side other sources, such as wind movements. 4.8.5.3 Pillars 4.8.5.3.1 A single pillar can be contained in intermediate points along its long and contentions relative or nodal. 4.8.5.3.2 The required strength and stiffness of the restraints on are given, respectively, by: P= br β

br

0004 N =

Sd

2γ N r Sd L b

Where: γ is the weighting coefficient of rigidity equal to 1.35; r NSdrequestor is the normal force calculation on the pillar; Lb is the distance from contention, observing the provisions in 4.8.5.3.4. 4.8.5.3.3 The strength and rigidity necessary nodal restraints, when these are equally spaced, are given respectively by: P=

001 N

29

br

Sd 8γ N β = r Sd br L b where NSd, Γr andbLare defined in 4.8.5.3.2.

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NBR 8800 - Based Text Revision

4.8.5.3.4 When the distance between the points of restraint is smaller than L Unlocked maximum length that allows the pillar resists normal force requestor calculation of the buckling coefficient k = 1.00, can take L

q, Where L q is b equal to Lq.

4.8.5.4 Beams 4.8.5.4.1 The contentions of a beam shall prevent the relative displacement of the top tables and bottom. Lateral stability of beams must be provided to prevent the restraint lateral displacement (translational containment), torsion (twisting restraint) or combination of the two movements. Bars subjected to bending with reverse curvature, inflection point can not be considered by itself as a restraint. 4.8.5.4.2 The contentions of translation can be relative or nodal and should be fixed near the compressed table. Additionally, the balance beams, a contention in end without support should be set close to the pulled table. Contentions translational must be fixed near both tables when located in the vicinity of the point inflection in beams subjected to reverse curvature. 4.8.5.4.3 The required strength and stiffness of contention for translation are given, respectively, by: P= br

β

br

0008

=

M

C Sd d h the

4γ M C r Sd d L h b the

Where: γ is the weighting coefficient of rigidity equal to 1.35; r M Sdis the bending moment calculation requestor; hthe is the distance between the centroid of the tables; Cd is a coefficient equal to 1.00, except for containment located in the vicinity of the point tipping in bars subjected to bending reverse camber, should be taken when equal to 2.00; Lb is the distance between restraints (length unlocked), observing the provisions in 4.8.5.4.5. 4.8.5.4.4 The required strength and stiffness of contention nodal translation are given, respectively, by: P= br

002

M

C Sd d

h the

Page 31 NBR 8800 - Based Text Revision β

=

br

31

10γ M C r Sd d L h b the

where MSdC dH the , Γr andbLare defined in 4.8.5.4.3. 4.8.5.4.5 When the distance between the points of restraint is smaller than L unlocked maximum length which allows the beam to resist the bending moment requester calculation, one can take G equal to L . b q

q, Where L q is

4.8.5.4.6 contentions torsional nodal or may be continuous along the length of the beam. Such contentions may be fixed in any position of the cross section, not needing to stay near the compressed table. 4.8.5.4.7 The contentions of nodal twist must have a connection with the beam capable of supporting the bending moment, M br, And a minimum stiffness gantry or diaphragm, β Tb, Whose values, respectively, are: 0024 M

Sd nC L b b

M= br

β

Tb

β

=

1-

T β

β

L

T

sec

Where: M SdandbLare defined in 4.8.5.4.3; L is the span of the beam; n is the number of nodal points of contention within the range; C is a modification factor defined in 5.4.2.5 and 5.4.2.6; b β is the stiffness of the containment excluding the distortion of the beam web, given by: T β = T

LM2 r Sd nE I C2 y b

2 γ4

β sec is the stiffness of the beam web distortion, including the effect of stiffeners Cross the soul, if any, given by: β

sec

=

t b3 3 3 E 1 5,h t 3 thew + s s h 12 12 the

γ is the weighting coefficient of rigidity equal to 1.35; r

E is the modulus of elasticity of steel;

Page 32 32

NBR 8800 - Based Text Revision I y is the moment of inertia of the beam about the axis situated in the bending plane; hthe is the distance between the centroid of the tables; t wis the thickness of the beam web; t s is the thickness of the stiffener; bs the width of the stiffener is located on one side (using twice the width of the stiffener for pairs of stiffeners).

If β secis less than β T, Β Tb will be negative, indicating that the containment torsion beam is not effective due to inadequate rigidity to the distortion of the beam web. When the stiffener is required, it must be extended to the total height of the bar contained and must be fixed to the table if containment torsion is also fixed to the table. Alternatively, the stiffener is allowed to interrupt a distance equal to any table of the beam that is not directly attached to the containment twist. When the spacing of the points of restraint is smaller than L q, Then L b may be taken equal to L 4.8.5.4.8 For the contentions of continuous torque must be used the same expressions given in 4.8.5.4.7, taking n L equal to 1.00 times and the rigidity per unit length, and rigidity to the distortion of the soul, β beam As: sec β

3 3Et3 w sec 12 h the =

4.9 Structural Integrity 4.9.1 The structural design, in addition to providing a framework capable of meeting the limit states past and the intended period of use for the building lifespan, should allow the manufacturing, shipping, handling and assembly of the structure are performed so proper and safe working condition. It must also take into account the need to future maintenance, demolition, recycling and reuse of materials. 4.9.2 The basic anatomy of the structure by which actions are transmitted to the foundations must be clearly defined. Any structure characteristics that influence the stability Global must be identified and properly considered in the design. Each part of a building between expansion joints should be treated as an isolated building. 4.9.3 The structure must be designed as a three-dimensional entity, must be robust and stable under normal load conditions and should not occur in the event that one accident or be used inappropriately, suffering disproportionate damage to their causes. In absence of specific sophisticated studies should be followed given prescriptions 4.9.4 to 4.9.8. 4.9.4 Each pillar of a building shall be effectively locked by means of struts (retainers) at least two horizontal directions, preferably orthogonal at each level supported by this pillar, including roofing, according to Figure 2.

t4 of w q.

Page 33 NBR 8800 - Based Text Revision

33

4.9.5 Continuous lines of struts should be placed as close as possible to the edges of the floor or roof line and each pillar, and reentrant corners anchors should be and connected to the structure according to Figure 2. Anchors of the pillars

Anchors edge

Reentrant corner Anchor for Dike the reentrant corner Anchors edge The Anchor for containment The abutment Anchors edge

Beams not used as anchors

Figure 2 - Example of bracing the pillars of a building 4.9.6 The horizontal struts may consist of steel profiles, including those used for other purposes, such as floor joists and hedge shears, or the reinforcement of slabs properly connected to the steel frame. 4.9.7 The horizontal struts and their connections must be compatible with the other elements of the structure to which they belong and be sized for shares calculation and also to withstand a pulling force calculation, which should not be added to other actions, at least 2% of the requesting force calculation on the pillar or 75 kN, whichever is greater. On case covers without concrete slabs, the struts of the pillars and their end their connections shall be designed for the actions of calculation and also to support a compressive force calculation, which should not be added to other actions, at least 75 kN. In addition, the struts must meet the applicable requirements given in 4.8.5. 4.9.8 In buildings with multiple floors, pillars of the amendments should be able to withstand a force corresponding to the larger reaction of traction calculation, obtained from the combination of load permanent and overhead applied on the pillar of a floor located between the amendment in consideration and positioned immediately below the seam. 5 Specific conditions for the design of steel elements 5.1 Relations width / thickness on tablets elements of steel profiles 5.1.1 Classification of cross sections 5.1.1.1 Depending on the value of the slenderness of the compressed components in relation to λ p andrλ(To see 5.1.1.2), respectively slenderness parameter corresponding to the lamination and parameter slenderness corresponding to the onset of yield, the cross sections are classified into:

Page 34 34

NBR 8800 - Based Text Revision - Compact: sections tablets whose elements have not exceed the slenderness parameter λ and whose tables are connected continuously to the soul or souls (see 5.1.1.3); p - Semicompactas: sections that have one or more elements tablets exceeding the parameter λ pBut not the parameter λ r (See 5.1.1.4); - Slender: sections that have one or more elements tablets exceeding the parameter λ r (See 5.1.1.5).

5.1.1.2 The slenderness of compressed elements is defined in 5.1.2 and the parameters of slenderness λ andrλare provided for different request types along this Standard.

p

5.1.1.3 Compact sections are capable of achieving a stress distribution "fully Plastic "and have a great rotation before the occurrence of local buckling. These sections are suitable for cosmetic analysis, but should, for this type of analysis, having a shaft symmetry in the plane of loading when subjected to bending, and be doubly symmetric when subjected to normal compression forces. 5.1.1.4 semicompactas In sections, the tablets reach the resistance elements runoff before local buckling occurs, but not resist inelastic local buckling the intensity of tension required to achieve "fully plastic" distributing strains. 5.1.1.5 In the sections slender elements tablets before flambam resistance flow is achieved. 5.1.2 Types and slenderness of the component elements 5.1.2.1 For the purposes of local buckling, the elements of the cross sections usual, except the circular tubular sections are classified into AA when have two linked longitudinal edges, and AL, when they have only one longitudinal edge bound. 5.1.2.2 The slenderness of the component elements of the cross section is defined by the relationship between width and thickness (ratio b). t / 5.1.2.3 The width (b) of some of the most common AA elements should be taken as follows: a) for the souls of sections I, H or U-rolled, the free distance between the two tables less rays of agreement between table and soul; b) for the souls of sections I, H, U or welded coffin, the free distance between tables; c) for welded sections coffin tables, the free distance between the inner faces of the souls; d) to souls rectangular tubular sections and tables, the length of the flat part of the element; e) for plates, the distance between the parallel lines of fasteners or welding. 5.1.2.4 The width of some of the most common elements AL should be taken as follows:

Page 35 NBR 8800 - Based Text Revision

35

a) sections of tables for I, H and T, half of the total width of the table; b) to flaps and gussets U sections tables, the total width of the element; c) for plates, the distance from the free edge to the first row of bolts or welding; d) for the souls of sections T, the total height of the cross section, including the height of the soul and the thickness table. 5.2 prismatic bars subjected to normal traction force 5.2.1 General 5.2.1.1 This subsection applies to prismatic bars subjected to normal traction force caused by static actions, including bars linked by pins and lugs and round bars with Threaded ends. 5.2.1.2 In the design, the condition must be met: N

TSd

≤N

TRd

Where: N is the normal force of requesting traction calculation, determined from the t, Sd combinations of actions given in 4.7.2; Nt, Rdis the normal force of sturdy traction calculation, determined according to 5.2.2, 5.2.6 or 5.2.7, whichever is applicable. The condition specified in 5.2.8 should still be met, relating to the maximum value of slenderness ratio and, in the case of a bar composed, must be met given the rules in 5.2.9. 5.2.2 sturdy Normal force calculation The normal force resistant traction calculation, N To be used in the design, except t, Rd for round bars with threaded ends and bars linked by pins, is the smallest of values ​ obtained, considering the limit states for disposal of gross section and Liquid break section according to the expressions given below: a) for the disposal of the gross section N

TRd

=

The f g y γ

b) to break the net section N Where:

Page 36

TRd

=

The f andu γ

36

NBR 8800 - Based Text Revision γ is the weighting coefficient of resistance, equal to 1.10 for disposing of gross section and 1.35 for net section rupture; The the bar; g is the gross cross-sectional area of ​ The is the effective net area of ​ cross section, given bar as 5.2.3; and f y is the yield strength of steel; f u is the tensile strength of steel.

5.2.3 Effective Net Area The effective net area of ​ a bar, The

Is given by: and

A = C The and t n Where: The n is the net area, as determined Bar 5.2.4; Ct is a reduction coefficient of net area determined according to 5.2.5. 5.2.4 Net Area 5.2.4.1 In regions with holes, made ​ for switching or for any other purpose, the area Net, The , A bar is the sum of the thickness of the liquid products width of each n element, calculated as follows: a) bolted to the width of the holes must be considered greater than 2.0 mm nominal size of these holes, defined in 6.3.5, perpendicular to the direction of the force applied; b) if a series of holes distributed transversely to the axis of the bar in to this axis diagonal or zigzag, the net width of that part of the bar shall be calculated by deducting from the gross width the sum of the widths of all the holes in the chain, and adding to each line connecting the two holes, the amount s 2 4 g , And Mon respectively, the longitudinal and transverse spacings (feedback) between these two holes; c) the net width of that critical part of the bar will be obtained by the chain holes gives the least net widths for the different possibilities of lines break; d) for angles, feedback g holes in opposite flaps should be considered equal to sum of jigs, measured from the edge of the ledge, subtracted from its thickness; e) in determining the net section area comprising welds or welds buffer Fillet holes in the area of ​ the weld metal must be discarded.

Page 37 NBR 8800 - Based Text Revision 5.2.4.2 In areas where there are no holes, the net area, A

37 , Should be taken equal to the area

gross cross section, The

g.

n

5.2.5 Reduction Coefficient 5.2.5.1 The reduction coefficient of net area, C t, Bars with cross sections constituted by more than one rectangular element, including rectangular tubular sections has the following values: a) when the traction force is transmitted directly to each of the elements of cross section of the bar, by welds or bolts: C = 100 t b) when the traction force is transmitted only by only by bolts or welds Longitudinal or by a combination of longitudinal and transversal welds to some, but not all, elements of the cross section of the bar (should, however, be used 0.90 as the upper limit and lower limit 0.75): and C =1- c t l c Where (Figure 3): and c is the eccentricity of the bond, equal to the distance from the center of gravity of the bar, L, the shear plane of the connection (in profiles with a plane of symmetry, the connection should be symmetrical in relation to this plane are considered and two separate bars and symmetric, each related to a shear plane of the connection, for example, two T sections in case I or H profiles linked the tables); l cIn the welded joints, the length of the link is equal to the length of welding and bolted in is the distance from first to last screw thread drilling with larger screws, toward the normal force;

and c Higher T G and c lc

Lower T

lc

Figure 3 - Illustration of values ​ and and in cross sections consisting of c lc flat elements c) when the traction force is transmitted only by transverse welds:

Page 38 38

NBR 8800 - Based Text Revision The c C= t The g

Center of gravity higher T Center of gravity lower T and c

Where: The the connected elements; c is the cross-sectional area of ​ The the bar. g gross cross-sectional area of ​ 5.2.5.2 The reduction coefficient of net area, C t, The flat plates when the traction force is transmitted only by longitudinal welds along both its edges, has following values: C = 100 To t

l

C = 087 To t

2b > l

C = 075 To t

1 5,b > l ≥ b w

w

≥ 2b w

≥ 1 5,b

Where: l w is the length of the weld; b is the plate width (distance between the welds located on both edges). 5.2.5.3 The reduction coefficient of net area, C Circular has the following values:

t, Bars with tubular cross sections

a) when the traction force is transmitted almost uniformly throughout the cross section, by welds or bolts: C = 100 t b) when the traction force is transmitted to only a portion of the cross section, as in the situation shown in Figure 4, the procedure should be used as in b) of 5.2.5.1.

Page 39 NBR 8800 - Based Text Revision

39 Centre of gravity semi-circle top

and c and c lc

Centre of gravity lower semi-circle

Figure 4 - Illustration of transmission of force to the tubular part of circular cross section 5.2.6 bars connected by pin and lugs 5.2.6.1 bars connected by pin 5.2.6.1.1 The normal force resistant traction calculation of a bar connected by pin except eyebolts, is the lowest value considering the following limit states: a) disposing of gross section tensile as 5.2.2; b) pressure resistance of the projected contact area of ​ the pin, as 6.6.1; c) rupture of the net section tensile N

TRd

=

2 bt f f u γ

d) rupture of the net section shear N

TRd

=

060 The f sf u γ

with The = t2 to+( d / ) 2 sf p Where: γ is the weighting coefficient of resistance equal to 1.35; t is the thickness of the plate connected by the pin; bf is an effective width equal to t2 +16 mm But not more than the distance from the edge of hole to the nearest edge of the part measured in the direction perpendicular to the normal force acting; a is the shortest distance from the edge of the hole to the end of the bar measured in the direction parallel to the acting normal force;

Page 40 40

NBR 8800 - Based Text Revision dp is the diameter of the pin; f u is the tensile strength tensile steel.

5.2.6.1.2 the following requirements (Figure 5) must be met:

- The pin hole must be in the middle distance between the edges of the bar toward acting perpendicular to located the normal force; - When the pin's function also prevent relative movement between the parties connected, its diameter d pIt can be a maximum of 1.0 mm smaller than the hole, d

h;

- The length of the plate beyond the edge of the hole can not be smaller than

2 b(

and the distance can not be less than

133 b

f

f

+d ) p

(Bf , Dp and defined in 5.2.6.1.1);

- Corner bar, in addition to the through hole of the pin can be cut at angles 45 ° to the longitudinal axis, provided that the net cross-sectional area between the edge of hole and the cut edge, perpendicular to the shear plane, is not less than that required beyond the edge of the hole, parallel to the axis of the workpiece. B ≥ 2f + D p t

a ≥ 1.33 fb

The

bf

b 2

N

b

dh

N b 2

bf Section AA

The

dp 45 °

≥ 1.33 b f

Figure 5 - Plaque connected by pin 5.2.6.2 Eyelets The eyebolts are pieces for pin connections (Figure 6), which must meet the following requirements: -

have uniform thickness without additional reinforcement in the area of ​ passage of the pin;

-

the head should be circular, concentric with the through hole pin contour;

Page 41 NBR 8800 - Based Text Revision

41

the radius of the agreement between the head and the body of the ring (R) must be equal to or larger than the outside diameter of the eye (D) head; -

the plate thickness of the body of the lug (t) can not be less than 13 mm;

distance from the edge of the hole to the edge of the plate in the direction perpendicular to the force applied must be greater than 2 3 /the width of the ring body; -

the pin diameter may not be less than

7 8 / the width of the ring body, and

off the pin in the hole, d hCan not be greater than 1.0 mm. Met these requirements, the normal force of sturdy traction calculation, N determined according to 5.2.2, for the ultimate limit state flow of gross section, with an gross area equal to the width of the body of the grommet, b, the thickness t (Figure 6).

, Must be t, Rd

R≥D t ≥ 13 mm

≥2 b 3

The

N

b

N Section AA

dp≤ dh≤ dp+ 1.0 mm

dp ≥7 8b ≥2 b 3

The

Figure 6 - Eyelet 5.2.7 Round bars with threaded ends 5.2.7.1 The normal force resistant traction calculation, N , The round bars with t, Rd threaded ends, it is the smallest of the values ​ considering the limit states of disposing of gross section and break the threaded part. Such values ​ should be obtained from According to 5.2.2) and 6.3.3.2, respectively. 5.2.8 Index slenderness limit The slenderness ratio of tensile bars, K L r , Except rods round bars pre-tensioned or other bars that have been pre-assembled with voltage must be less than or equal to 300. 5.2.9 Bars composite tensile The composite tensile bars shall conform to the following rules (Figure 7): a) the longitudinal spacing between bolts or intermittent fillet welds connecting a plaque with a profile, or two plates in contact, can not be greater than:

Page 42 42

NBR 8800 - Based Text Revision - 24 or t greater than 300 mm, for bars made with unpainted resistant steel atmospheric corrosion or painted bars; - 14 or t greater than 180 mm, for bars made with unpainted steel not Resistant to atmospheric corrosion; b) the longitudinal spacing between bolts or intermittent welds connecting two or more contact sections can not be longer than 600 mm; c) profiles or plates, separated from each other by a distance equal to the thickness of Spacer plates must be interconnected through these spacer plates, so

D

the largest slenderness ratio of any profile or sheet between these connections, not exceed 300; d) can be used in the open faces continuous sheets with access openings or intermittent connecting plates, the latter being: a.

should have a length equal to or greater than 3 bolts or welds that connect to the main truss members;

The distance between two lines

b.

thickness should be less than screws or welding;

c.

should be connected to the main components by screws or welds intermittent longitudinal distance below or equal to 150 mm;

d.

should be spaced so that the greater spacing between plates connection must be such that the slenderness ratio greater l r / for each component principal, this range is not more than 300.

/1 50 the distance between lines

Page 43 NBR 8800 - Based Text Revision N

r 5.2.9-a Ve

N

43 N

N

lete phi and d

600mm ≤ Screws

300 ≤ Screws max /(LR)

3 ≥2b /intermittent n

mm 150 ≤

I weld b

300 ≤

/max (LR) D lete phi and Thed B

The

intermittent n I weld 600mm ≤

r 5.2.9-a Ve

D

lete andl B phi d mm 150 ≤

intermittent n I weldC

b

C

N

N

2b 3 ≥ / Screws

N

N

t

rMin

Section AA

DC Court DD cut BB Cut Figure 7 - composite tensile bars

5.3 prismatic bars subjected to normal compressive force 5.3.1 General 5.3.1.1 This subsection applies to prismatic bars subjected to the normal force compression caused by static actions. 5.3.1.2 In the design, the condition must be met: N

≤N

C Sd

CRd

Where: Nc, Sdis the normal force of requesting compression calculation, determined from the combinations of actions given in 4.7.2;

Page 44 44

NBR 8800 - Based Text Revision Nc, Ris the normal force resistant compression calculation, determined as 5.3.2.

The condition specified in 5.3.5 should still be met, relating to the maximum value of slenderness ratio and, in the case of a bar composed, must be met given the rules in 5.3.6. 5.3.2 sturdy Normal force calculation The normal force resistant compression calculation, N c, R, A bar, considering the states ultimate limits of instability by bending, torsional or flexo-torsion and local buckling, should be determined by the expression: N

CRd

=

χ Q Thef g y γ

b/50 ≥

Where: γ is the weighting coefficient of resistance to compression, equal to 1.10; χ is the factor associated with resistance to compression reduction, given in 5.3.3; Q is the local buckling coefficient, whose value should be obtained from Annex E; The the bar; g is the gross cross-sectional area of ​ f y is the yield strength of the steel. 5.3.3 Reduction factor χ 5.3.3.1 The reduction factor associated with resistance to compression, χ, depends on the curve sizing the compression (a, b, c or d), which is the type of cross section, the mode instability and the axis for which instability occurs, according to . Table 3 Their values ​ can be obtained from figure 8 and in Table 4 or determined by: 1

χ =

β + (β 2 - λ 2 ) the

≤ 1 0,

With ( ) β = 0 5, 1 + [ α λ - 0 2 + λ2] the the where α is related to the scaling coefficient curve compression and λ reduced slenderness, given respectively in 5.3.3.2 and 5.3.3.3.

theis the index

5.3.3.2 The coefficient α, in cases of instability due to bending is equal to 0.21, 0.34, 0.49 and 0.76, curves respectively for sizing compression. In cases of instability by twisting or flexion-torsion, α should always be taken equal to 0.34 (Ie, the curve b to be used).

Page 45 NBR 8800 - Based Text Revision 5.3.3.3 The reduced slenderness ratio, λ λ

= the

QN N

For compressed bars is given by: the

pl

and

Where: Q is the local buckling coefficient obtained from Annex E; Np is the flow corresponding to the cross section normal force, equal to the product l The f (A is the gross cross-sectional area and f the yield strength of steel); y g y g Nand is the normal force of elastic buckling, obtained as Annex K, depending on buckling length (see 5.3.4). 5.3.4 Length of buckling

45

The buckling coefficient K allows to obtain the buckling length of the rod, should be determined in accordance with 4.8.

Page 46 46

NBR 8800 - Based Text Revision Table 3 - Curves sizing Compressive instability due to bending Cross section

Instability around the axis

3)

Tubular sections

No soldering longitudinal

the Any

With solder longitudinal Sections welded coffin

d

tf

tw b

d t / < 30 w

Other cases

Sections H and I rolled y

b t / < 30 f

Welds great thickness to>( 0 t5 ) f

d b> / 12

t ≤ 40 mm f

Curve 1) 4)

c

Any

c

Any

b

x- x

the

y- y

b

tf d x

40 < t ≤ 100 mm f

x y b

d b≤ / 12

t ≤ 100 mm f t > 100 mm f

Sections I and welded H y

y

t1 x

x

t1 x

y

t2 x

y

x- x y- y x- x

b c b

y- y

c

Any

d

t ≤ 40 mm i (I = 1 and 2)

x- x

b 2)

y- y

c 2)

t > 40 mm i (I = 1 or 2)

x- x

c 2)

y- y

d 2)

Sections U, T and solid laminated Any

c

Any

b

L sections (angles) rolled

NOTES: 1)In cases of instability by twisting or flexion-torsion, it should be used to curve b. 2)If the soldier profile is manufactured by depositing weld metal plates cut with a torch, can be used to curve b for any instability about the axis. 3)Sections not included in the table are classified analogously. 4)For compressed composite bars, subject to the limitations of 5.3.6 should be adopted curve c for instability relative to the axis that does not intersect the major components profiles.

Page 47 NBR 8800 - Based Text Revision

47

χ 1,000 0,900

the

0,800 0,700 0,600

b

0,500 0,400

d

0,300 0,200

c

0,100 0.000 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00 λ the Figure 8 - dimensioning the compression curves (see Table 3)

Table 4a - Values ​ of χ for the curve ( α = 0.21) λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

0.00 1,000 1,000 1,000 0,977 0,953 0.924 0,890 0,848 0,796 0,734 0.666 0.596 0,530 0,470 0,418 0,372 0,333 0,299 0,270 0,245 0,223 0,204 0,187 0,172 0,159 0,147 0.136 0,127 0,118 0,111 0,104

0.01 1,000 1,000 0,998 0.975 0,950 0.921 0,886 0,843 0,790 0,727 0,659 0,589 0,524 0,465 0,413 0,368 0,330 0,296 0,268 0,243 0,221 0,202 0,185 0,170 0,157 0,146 0,135 0,126 0,117 0,110 -

0.02 1,000 1,000 0,996 0,973 0,947 0.918 0,882 0.838 0,784 0,721 0,652 0,582 0,518 0,459 0,408 0,364 0,326 0,293 0,265 0,240 0,219 0,200 0,184 0,169 0,156 0,145 0.134 0,125 0,117 0,109 -

0.03 1,000 1,000 0,993 0,970 0,945 0,915 0,878 0,833 0,778 0,714 0,645 0,576 0,511 0.454 0,404 0.360 0,323 0,290 0,262 0,238 0,217 0,198 0,182 0,168 0,155 0,143 0,133 0,124 0,116 0,108 -

0.04 1,000 1,000 0.991 0,968 0.942 0,911 0,874 0,828 0,772 0,707 0,638 0,569 0,505 0,448 0,399 0,356 0,319 0,287 0,260 0,236 0,215 0,197 0,180 0,166 0,154 0,142 0,132 0,123 0,115 0,108 -

0.05 1,000 1,000 0,989 0,966 0.939 0,908 0,870 0,823 0,766 0,700 0,631 0,562 0,499 0,443 0,394 0,352 0,316 0,284 0,257 0,234 0,213 0,195 0,179 0,165 0,152 0,141 0,131 0,122 0,114 0,107 -

0.06 1,000 1,000 0,987 0,963 0,936 0,905 0,866 0,818 0,760 0,693 0,624 0,556 0.493 0,438 0,390 0,348 0,312 0,281 0,255 0,231 0,211 0,193 0,178 0,164 0,151 0,140 0,130 0,122 0,114 0,106 -

0.07 1,000 1,000 0,984 0,961 0.933 0.901 0,861 0,812 0,753 0,686 0.617 0.549 0,487 0,433 0,385 0.344 0,309 0,279 0,252 0,229 0,209 0,192 0,176 0,162 0,150 0,139 0,129 0,121 0,113 0,106 -

0.08 1,000 1,000 0,982 0.958 0,930 0,897 0,857 0,807 0.747 0,680 0,610 0.543 0,482 0,428 0,381 0,341 0,306 0,276 0,250 0.227 0,207 0,190 0,175 0,161 0,149 0,138 0,129 0,120 0,112 0,105 -

0.09 1,000 1,000 0,980 0,955 0,927 0,894 0,852 0.801 0,740 0,673 0,603 0.536 0.476 0,423 0,377 0,337 0,303 0,273 0,247 0,225 0,205 0,188 0,173 0,160 0,148 0,137 0,128 0,119 0,111 0,104 -

λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

0.07 1,000 1,000 0.975 0,938 0,897 0,852 0,800 0,743 0,680 0.616 0,553 0,495 0.442 0,395 0,354 0,318 0,287 0,259 0,236 0,215 0,197 0,181 0,167 0,154 0,143 0,133 0,124 0,115 0,108 0,101

0.08 1,000 1,000 0,971 0,934 0,893 0,847 0,795 0.737 0,674 0,610 0,547 0,489 0,437 0,390 0,350 0,314 0,284 0,257 0,234 0,213 0,195 0,179 0,165 0,153 0,142 0,132 0,123 0,115 0,107 0,101

0.09 1,000 1,000 0,968 0,930 0,889 0,842 0,789 0.731 0,668 0,603 0.541 0,484 0,432 0.386 0,346 0,311 0,281 0,255 0,231 0,211 0,194 0,178 0,164 0,152 0,141 0,131 0,122 0,114 0,107 0,100

λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9

Page 48 48

NBR 8800 - Based Text Revision Table 4b - Values ​ of χ for curve b ( α = 0.34) λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9

0.00 1,000 1,000 1,000 0,964 0.926 0,884 0.837 0,784 0,724 0,661 0,597 0.535 0,478 0,427 0,382 0,342 0,308 0,278 0,252 0,229 0,209 0,192 0,176 0,163 0,151 0,140 0,130 0,121 0,113 0,106

0.01 1,000 1,000 0,996 0,960 0.922 0,880 0,832 0,778 0,718 0,655 0,591 0,529 0.473 0,422 0,378 0,339 0,305 0,275 0,250 0.227 0,208 0,190 0,175 0,162 0,149 0,139 0,129 0,120 0,112 0,105

0.02 1,000 1,000 0,993 0,957 0.918 0,875 0,827 0,772 0,712 0,648 0,584 0,523 0,467 0,417 0,373 0,335 0,302 0,273 0,247 0,225 0,206 0,189 0,174 0,160 0,148 0,138 0,128 0,119 0,112 0,105

0.03 1,000 1,000 0,989 0,953 0,914 0,871 0,822 0,766 0,706 0,642 0,578 0,518 0,462 0,413 0.369 0,331 0,299 0,270 0,245 0,223 0,204 0,187 0,172 0,159 0,147 0,137 0,127 0,119 0,111 0,104

0.04 1,000 1,000 0,986 0,949 0,910 0,866 0,816 0,761 0.699 0,635 0,572 0,512 0,457 0,408 0,365 0,328 0,295 0,267 0,243 0,221 0,202 0,186 0,171 0,158 0,146 0.136 0,126 0,118 0,110 0,103

0.05 1,000 1,000 0,982 0,945 0.906 0,861 0,811 0,755 0,693 0,629 0,566 0,506 0.452 0,404 0,361 0,324 0,292 0,265 0,240 0,219 0,200 0,184 0,169 0,157 0,145 0,135 0,125 0,117 0,109 0,103

0.06 1,000 1,000 0,979 0.942 0.902 0,857 0.806 0.749 0,687 0.623 0,559 0,500 0,447 0,399 0,357 0,321 0,289 0,262 0,238 0,217 0,199 0,182 0,168 0,155 0,144 0.134 0,125 0,116 0,109 0,102

3.0

0,099

-

-

-

-

-

-

-

-

-

3.0

0.09 1,000 1,000 0.954 0.903 0.849 0,791 0.731 0,668 0,606 0,546 0,490 0,439 0,393 0,353 0,318 0,287 0,260 0,237 0,216 0,198 0,182 0,168 0,155 0,144 0,133 0,124 0,116 0,109 0,102 0,096 -

λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

Table 4c - Values ​ of χ for curve c ( α = 0.49) λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

0.00 1,000 1,000 1,000 0,949 0,897 0,843 0,785 0,725 0,662 0,600 0,540 0,484 0,434 0.389 0,349 0,315 0,284 0,258 0,235 0,214 0,196 0,180 0,166 0,154 0,143 0,132 0,123 0,115 0,108 0,101 0,095

0.01 1,000 1,000 0,995 0,944 0,892 0.837 0,779 0,718 0,656 0,594 0,534 0,479 0,429 0,385 0,346 0,311 0,281 0,255 0,232 0,212 0,195 0,179 0,165 0,153 0,141 0,132 0,123 0,115 0,107 0,101 -

0.02 1,000 1,000 0,990 0.939 0.887 0,832 0,773 0,712 0,650 0,588 0,528 0,474 0,424 0,380 0,342 0,308 0,279 0,253 0,230 0,210 0,193 0,177 0,164 0,151 0,140 0,131 0,122 0,114 0,107 0,100 -

0.03 1,000 1,000 0,985 0,934 0,881 0.826 0,767 0,706 0,643 0,582 0,523 0,469 0,420 0,376 0,338 0,305 0,276 0,250 0,228 0,209 0,191 0,176 0,162 0,150 0,139 0,130 0,121 0,113 0,106 0,099 -

0.04 1,000 1,000 0,980 0.929 0,876 0,820 0,761 0,700 0.637 0,575 0,517 0,463 0,415 0,372 0,335 0,302 0,273 0,248 0,226 0,207 0,190 0,174 0,161 0,149 0,138 0,129 0,120 0,112 0,105 0,099 -

0.05 1,000 1,000 0.975 0,923 0,871 0,815 0,755 0.694 0,631 0,569 0,511 0,458 0,411 0,368 0,331 0,299 0,271 0,246 0,224 0,205 0,188 0,173 0,160 0,148 0,137 0,128 0,119 0,111 0,104 0,098 -

0.06 1,000 1,000 0,969 0.918 0,865 0.809 0.749 0,687 0,625 0,563 0,506 0,453 0,406 0,364 0,328 0,296 0,268 0,243 0,222 0,203 0,186 0,172 0,159 0,147 0.136 0,127 0,118 0,111 0,104 0,097 -

0.07 1,000 1,000 0,964 0,913 0,860 0,803 0,743 0.681 0.618 0,558 0,500 0,448 0,402 0,361 0,324 0,293 0,265 0,241 0,220 0,201 0,185 0,170 0,157 0,146 0,135 0,126 0,118 0,110 0,103 0,097 -

0.08 1,000 1,000 0,959 0,908 0,854 0,797 0.737 0,675 0,612 0.552 0,495 0,443 0,397 0,357 0,321 0,290 0,263 0,239 0,218 0,200 0,183 0,169 0,156 0,145 0.134 0,125 0,117 0,109 0,102 0,096 -

Page 49 NBR 8800 - Based Text Revision

49

Table 4d - Values ​ of χ curve for d ( α = 0.76) λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

0.00 1,000 1,000 1,000 0,923 0,850 0,779 0,710 0,643 0,580 0.521 0,467 0,419 0,376 0,339 0,306 0,277 0,251 0,229 0,209 0,192 0,177 0,163 0,151 0,140 0,130 0,121 0,113 0,106 0,100 0,094 0,088

0.01 1,000 1,000 0,992 0,916 0,843 0,772 0,703 0.637 0,574 0,515 0,462 0,414 0,372 0,335 0,302 0,274 0,249 0.227 0,207 0,190 0,175 0,162 0,150 0,139 0,129 0,121 0,113 0,106 0,099 0,093 -

0.02 1,000 1,000 0,984 0,909 0,836 0,765 0,696 0,630 0,568 0,510 0,457 0,410 0,368 0,332 0,299 0,271 0,247 0,225 0,206 0,189 0,174 0,160 0,149 0,138 0,128 0,120 0,112 0,105 0,098 0,093 -

0.03 1,000 1,000 0,977 0.901 0.829 0,758 0,690 0,624 0,562 0,504 0.452 0,406 0,364 0,328 0,296 0,269 0,244 0,223 0,204 0,187 0,172 0,159 0,147 0,137 0,127 0,119 0,111 0,104 0,098 0,092 -

0.04 1,000 1,000 0,969 0,894 0,822 0,751 0,683 0.617 0,556 0,499 0,447 0,401 0,361 0,325 0,293 0,266 0,242 0,221 0,202 0,186 0,171 0,158 0,146 0.136 0,127 0,118 0,110 0,104 0,097 0,091 -

0.05 1,000 1,000 0,961 0.887 0,815 0.744 0,676 0,611 0,550 0.493 0.442 0,397 0,357 0,321 0,291 0,263 0,240 0,219 0,200 0,184 0,170 0,157 0,145 0,135 0,126 0,117 0,110 0,103 0,097 0,091 -

0.06 1,000 1,000 0.954 0,879 0,808 0,738 0,670 0.605 0,544 0,488 0,438 0,393 0,353 0,318 0,288 0.261 0,237 0,217 0,199 0,183 0,168 0,156 0,144 0.134 0,125 0,116 0,109 0,102 0,096 0,090 -

0.07 1,000 1,000 0.946 0,872 0,800 0.731 0,663 0.598 0,538 0.483 0,433 0,388 0,349 0,315 0,285 0,258 0,235 0,215 0,197 0,181 0,167 0,154 0,143 0,133 0,124 0,116 0,108 0,102 0,095 0,090 -

0.08 1,000 1,000 0,938 0,865 0,793 0,724 0,656 0.592 0.532 0,477 0,428 0,384 0,346 0,312 0,282 0,256 0,233 0,213 0,195 0,180 0,166 0,153 0,142 0,132 0,123 0,115 0,108 0,101 0,095 0,089 -

0.09 1,000 1,000 0,931 0,858 0.786 0.717 0,650 0,586 0,526 0,472 0,423 0,380 0,342 0,309 0,279 0,254 0,231 0,211 0,194 0,178 0,164 0,152 0,141 0,131 0,122 0,114 0,107 0,100 0,094 0,089 -

λthe 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

5.3.5 Index slenderness limit The slenderness ratio KL r For / compressed bars can not be greater than 200. 5.3.6 Composite Bars 5.3.6.1 Dimensioning The composite bars compressed must be scaled obeying the subsections 5.3.1 to 5.3.5. However, the mode of instability involve producing deformations on shear forces in the connecting elements of the components of these profiles bars, index slendernessKL r / mode instability and bending of the bending mode instability in flexion-torsion should be modified, assuming the following values: a) if the connectors are connected to the bar profiles consisting of screws with normal grip: KL r

= m

the 2 r the i

KL 2 r

+

b) if the connectors are connected to the bar profiles consisting of screws prestressed or soldering:

Page 50 50

NBR 8800 - Based Text Revision KL r

= m

KL 2 r

+ 082 the

( h

)( ) r2 2 ther 2 ib ib ( ) 1 + h r2 2 ib

Where: ( KL / ) Ris the slenderness of the composite bar; the a is the distance between the connecting elements of the components of the composite bar profiles; r i is the minimum radius of gyration of a component of the composite profile bar; r ib is the radius of gyration of a component of the composite profile bar relative to its axis main parallel to the axis of bending buckling of composite bar inertia; h is the distance between the centers of gravity of the components of the composite profiles in bar direction perpendicular to the axis of buckling. 5.3.6.2 Requirements for the design 5.3.6.2.1 Along the length of composite bars, the longitudinal spacing intermittent welds or screws must be suitable for the transfer of requests active. Related to maximum spacing limitations and maximum distance between holes of a hole the edges, see 6.3.9. 5.3.6.2.2 At the ends of composite rods compressed supported on base plates or

Machined surfaces, all components in contact withwidth each other bescrew connected by welding Continuing having a length not less than the largest of themust bar or the longitudinal spacing can not exceed four diameters in length not less than 1.5 times the greatest width of the bar. 5.3.6.2.3 In cases where the bar has composed the external profiles sheets, spacing maximum can not exceed 0.75 t E f Or 305 mm, thickness ta of the outer sheet y thinner, when there screws in all longitudinal lines drilling or welding intermittently along the edges of the components of the section. When bolts or welds Intermittent are lagged, the maximum spacing on each line drilling or welding does not can overcome 112 t E f , And ta thickness thinner outer plate can not be y greater than 460 mm. 5.3.6.2.4 Bars compressed composite of two or more profiles in touch with lost or equal to the thickness of spacer plates must have links from these profiles at intervals regular, so that the slenderness ratio l r / any profile between two connections adjacent, does not exceed 3/4 of the slenderness ratio of the composite bar unless use more accurate to determine the resistance of the bar process. For each profile component, the slenderness ratio should be calculated on your minimum radius of gyration. 5.3.6.2.5 The open faces of composite plates compressed bars or profiles should be travejamento provided with lattice plates as well as at each end, and also plates at intermediate positions of the bar if there is interruption travejamento. Such plates

Page 51 NBR 8800 - Based Text Revision

51

should extend as much as possible to the longitudinal sides of the bar. Furthermore, the plates edge should have a length not less than the distance between the screws or welds that connect to the main truss members. Plates in intermediate positions should have a length not less than half that distance. The thickness of the plates can not be less than 50 /1 welds connecting these plates to the main truss members.

the distance between lines of bolts or

In the case of bolted plates, the longitudinal spacing of the screws can not be greater six diameters and each plate must be connected to each main component with minimal three screws. In the case of welded plates, each weld line joining a sheet to a component page should have a sum of lengths of not less than 3 / 1 the length of the plate. 5.3.6.2.6 Elements of travejamento lattice, they are flat bars, angles, shapes U profile or any other, should be arranged such that the slenderness ratio l r / of each major component, between the points of attachment of travejamento does not exceed the rate slenderness of the bar as a whole. The elements of travejamento shall be designed to resist a shear force requesting calculation, normal to the axis of the bar equal to 2% of the strength of the requesting Compression calculation that acts on the composite bar. The slenderness ratio l r / of elements in travejamento simple arrangement can not be greater 140 that, in a double arrangement (array X), than 200. the length L is taken equal to free length between bolts or welds that connect the elements of the travejamento the main components, in the case of simple arrangement, and 70% of the length of the case arrangement X. In dual arrangement (X) must be a link between the elements of travejamento in

intersection thereof. The angle of inclination of elements travejamento to the longitudinal axis of the bar, preferably, should not be less than 60 º to 45 º and simple arrangement for double arrangement (X). When the transverse distance between the screws or welds that connect the elements travejamento the main components exceeds 380 mm, the arrangement must preferably be double (X) or consisting of angles. 5.3.6.2.7 travejamento elements may be replaced by continuous plates with a succession of access openings. The net width of these plates, the corresponding sections to openings may be considered participating in resistance to normal force, provided that: a) their relationship b t / is limited to

186 E f ; y

b) the relationship between the length (in the direction of the normal force) and the gap width not is greater than 2;

Page 52 52

NBR 8800 - Based Text Revision c) the clear distance between openings in the direction of the normal force, is not less than the transverse distance between nearest lines of fasteners or welds that connect these plates to the main components; d) the openings have a minimum radius of 38 mm around the perimeter.

5.3.6.2.8 The requirements for compressed composite rods are illustrated in Figures 9 , and 10. Replacing travejamento lattice by regularly spaced plates forming travejamento in context, is not covered by this Standard. In this construction, the reduction of resistance due to shearing distortion can not be ignored. N

And y f mm and 12 t 460 1 ≤ ≤

And y f mm and 75 t 0, ≤ ≤ 305 And y f mm and 12 t 460 1 ≤ ≤ And y f The mm and 75 t 305 0, ≤ ≤

N

N

tes sthe iten m d ryou the fas in of the ld So

l tno onju et s iten the C ) max rm nh you read KL (r in 3 in the ≤4 ld So m )/ R ax (l sso of o fu sa he the tn rtthe P fand d onjuB C ) max r KL 3(≤4 the The sso nh m ax fu he read )/ R rtthe P in (l

sthe fusion For

B

l

to un et s iten rm you in the

x the conj the m ) r KL 3( 4 ≤

b 1.5 ≥

l

and ad sofd im b and tio gatre 1.0 Li ex ≥

b 4d ≤

ld So

m )(l/ R ax C

C

b N

Baseplate or machined surface

N

N

rMin t

DC Court rMin BB Cut

Section AA

Figure 9 - composite bars compressed

Page 53 NBR 8800 - Based Text Revision

53 b ≤ 1.86fEyt

t

GG Cut

t

rMin EE Court

and ad id in tr x and ad ap h C E

X u the he ltu p d jthe ran air in the en m eja raTv

N b

3 sso b mo ≥ nithe míRafu p

b 6 ≤ dE

N

G l 0 1≤ 20 7/ lR 0,

ithe IAR d and term

≥ °45

G

tn o jn c)ruo (≤ l KL x ma /(LR)

In plate

b ≥ b

b≥2

L ples sim tjhe ran air in he ten m eja ar v T

≥06° and tremidad x and and l 14 ad ≤0 ap l/1R Ch b ≥

F b

r les tn o the p ple jn c)ruo us m sor du rthe to KL l (≤ 80to n hey myes and o nn 3 t n L > x j ove a m j b ma AC and he /(LR)rtPa c / travbeam Solder Length F total weld2 3≥

2 ≤D H

8 ≥r 3 D

b ≤ 1.86fEyt

H

t

N r1= Radius of gyration minimum element of travejamento

FF Cut

b≥50

HH Court

n m rí

Figure 10 - Composite Bars compressed 5.4 prismatic bars subjected to bending normal single 5.4.1 General 5.4.1.1 This subsection shall apply to the design of prismatic bars subjected to normal single static bending caused by actions under the following conditions:

Page 54 54

NBR 8800 - Based Text Revision - I and H sections with two axes of symmetry flexed around one of these axes; - Sections I and H with an axis of symmetry in the plane of the soul flexed around the axis center of inertia perpendicular to the soul; - U sections flexed around a central axis of inertia; - Tubular sections and rectangular casket with two axes of symmetry flexed around of these axes; - Solid circular or rectangular sections, flexed around a central axis inertia; - Circular tubular sections flexed around any axis passing through the center of gravity.

5.4.1.2 The transverse loading should always be on a plane of symmetry, except U-profiles bent in relation to the axis perpendicular to the soul, when the result of the load must pass through the shear center of the cross section. 5.4.1.3 In sizing so that the last limit states occur not related to performances of the bending moment and shear force, must be met the following conditions: M

Sd

≤M

Rd

V ≤V Sd Rd Where: M Sd requestor is the bending moment calculation, derived from the combinations of actions given in 4.7.2; VSdshear strength is requesting calculation, derived from the combinations of actions given in 4.7.2; M Rdis resistant bending moment calculation determined according to 5.4.2;

VRdis resistant to shear force calculation, determined as 5.4.3. Must still be checked all limit states apply, as existing requirements in different parts of this Standard. 5.4.2 resistant bending moment calculation 5.4.2.1 The calculation resistant bending moment, M M

Rd

=

RdIs given by:

M Rk γ

Where:

Page 55 NBR 8800 - Based Text Revision γ is the weighting coefficient of resistance to bending, equal to 1.10; M Rkis the characteristic resistant bending moment determined according to 5.4.2.2. 5.4.2.2 The characteristic resistant bending moment, M RkShould be determined according to Annexes D or F, as applicable, complying with the provisions of 5.4.2.3 to 5.4.2.7. Are apply, as appropriate, the ultimate limit states of lateral torsional buckling with (FLT) local buckling of the compressed table (FLM), local buckling of the soul (FLA), local buckling wall of the pipe (FLP) and the pulled flow table (EMT). 5.4.2.3 The characteristic values ​ of bending moment resistant to buckling limit state with lateral torque (FLT) are only valid for the application of external forces on the center level shear of the cross section and can not be used when there forces destabilizing, ie, forces whose direction deviates from the shear center of the section cross during buckling. When used in the case of stabilizing forces, ie forces whose direction approaches the shear center of the cross section during buckling, lead to conservative results. 5.4.2.4 To ensure the validity of the elastic analysis, the moment resistance characteristic not can be taken greater than 150 W f , W being the minimum elastic modulus of resistance of y section in relation to the bending axis f y the yield strength of the steel. 5.4.2.5 For the determination of characteristic bending moment resistant to limit state FLT, may be necessary to calculate a modification factor for bending moment diagram does not uniform length for the unlocked (U b) Analyzed. This factor, except for the situation provided in 5.4.2.6, is given by: - Beams cantilevered from a section in the lateral torsional buckling with (see 4.8.5.4) and the end not supported without restraint: C = 100 b - In all other cases: C = b 2 5,M Where:

12 5,M max +3 M + 4 M + 3 M max The B C

55

M max is the value of the maximum moment requestor calculation in module, the Unlocked length; M is the value of the applicant moment calculation, module, the section located at a The quarter of the length unlocked; M B is the value of requesting time calculation in module, the central section of Unlocked length; M C is the value of the applicant moment calculation, module, located in section three quarter length unlocked.

Page 56 56

NBR 8800 - Based Text Revision

In checking the FLT, should be taken as bending moment calculation requesting the largest time (positive or negative) in length unlocked considered. 5.4.2.6 In beams with sections I, H and U flexed around the central axis of inertia perpendicular the soul, and rectangular tubular sections coffin and flexed around a central axis of inertia, unlocked in a length (L b) In which one of the tables is free to move laterally and the other table has continuous lateral restraint against this type of displacement, modification factor for nonuniform bending moment is given by: - When the table with continuous lateral restraint is pulled in at least one unlocked edge length: M 2 M 8 12 C = 300 b 3M 3 (M + M ) 0 0 1 Where: M 0 is the largest value of requesting time calculation that pulls the table with continuous lateral restraint at the ends of the length unlocked, with sign negative; M 1 is the value of the bending moment calculation requesting the other end of length unlocked (if that moment to pull free table, will have positive sign the second term of the equation and should be taken equal to zero in the third term and pull the table with continuous lateral restraint, will have a negative sign in the second and third terms in the equation); M 2 requestor is the bending moment calculation in the central section of length unlocked, with a positive sign if the free traction table and a negative sign if tractionate table with continuous lateral restraint. - In stretches with zero moment at the ends, subjected to an action evenly distributed, with only the table contained continuously pulled against lateral displacement: C = 200 b - In all other cases: C = 100 b

In checking the FLT, should be taken as bending moment calculation requesting the largest time length considered unlocked, the region in which the non-compressed table is contained against lateral displacement. 5.4.2.7 The beams, with or without reinforcement plates table (lamellae - see 5.4.4), even with holes screw on the tables, can be scaled to the bending moment on the basis of gross section properties, since 075 f The ≥ 090 f The in both tables. On u fn y fg However, if at any table, 075 f The < 090 f The The resistant bending moment u fn y fg

Page 57 NBR 8800 - Based Text Revision

57

characteristic, M RkCan not be taken more than Wf, and the properties of the cross section y shall be calculated based on the effective area of ​ the pulled table, The feGiven by: 5 f u The fnt 6f y

A= fe Where:

f is the yield strength of steel; y f u is the tensile strength tensile steel; W is the least resistant elastic modulus of the cross section, determined by taking pulled to the table area A fe; The tensioned or compressed table, whichever is applicable, calculated fn is the net area of ​ accordance with 5.2.4; The the pulled table, calculated in accordance with 5.2.4; fnt is the net area of ​ The tensioned or compressed table, whichever is applicable. fg is the gross area of ​ 5.4.3 resistant shear force calculation 5.4.3.1 The sturdy shear calculation, V V

Rd

=

RdIs given by:

V Rk γ

Where: V is the shear resistant feature, determined in accordance with 5.4.3.2 or Rk 5.4.3.3, as applicable; γ is the weighting coefficient of resistance to bending, equal to 1.10. 5.4.3.2 Sections I, H and U flexed around the axis perpendicular to the soul and sections coffin and rectangular tubular 5.4.3.2.1 In section I, H and U flexed around the central axis of inertia perpendicular to the soul and coffin rectangular tubular sections and flexed around a central axis of inertia, strength shear resistant feature, V Is given by: Rk

λ ≤λ

a) for

V= Rk λ

b) To

p

V

lp

λ

c) To

V

Rk

r

= 128

λ

p λ

2 V

lp

Where: λ=

λ

p

h t

w

= 110

λ = 137 r

k

E v f y

k

E v f y

5 5 + () , for theh 2 k = v 500 , for

the ≤3 h

2 the the 260 > 3 or > ( ) h h h t/ w

Vp is the shear force corresponding to the lamination (s) soul (s) for shear, l given in 5.4.3.2.2; a is the distance between the center lines of two adjacent transverse stiffeners; h is the vertical clearance of the soul between tables; t wis the thickness (s) of core (s). 5.4.3.2.2 The cutting force corresponding to the lamination (s) soul (s) is given by shear by: V= pl

060 The f w y

In this equation, A w is the effective shear area, which should be taken equal to: a) souls in sections I, H and U:

td; w

b) in the symmetrical souls coffin and tubular rectangular sections:

2 th . w

Page 59 NBR 8800 - Based Text Revision where d is the total height of the cross section. 5.4.3.2.3 For sections I and H the following rules must be obeyed: a) the transverse stiffeners are welded to the (s) soul (s) and the tables of the profile, it may, however, the tensioned side of the table, be interrupted so that the distance between the nearest points of solders table / stiffener and soul / soul remains betweent4 and t6; w w b) width / thickness ratio of the elements forming the stiffeners can not exceed

055 E f ; y

c) the moment of inertia of the stiffener section of a single or a pair of stiffeners (One on each side of the web) in relation to the axis plane of the heart can not be less than ta3 j Where j = 2 [5, ()theh 2] - 2 ≥ 0 5,; w d) when h / tw is equal to or greater than 260, the ratio the[260 h ( t / ) ]2 ; w

the h / can not exceed 3 nor

e) if the stiffeners are attached by screws to the soul, the maximum spacing between centers of these screws can not exceed 300 mm. If solder fillets are used flashing, the clear distance between these fillets can not exceed 16 times the thickness of soul, nor 250 mm. In the case of sections U, coffin and rectangular tubes, these rules should be properly adapted. 5.4.3.2.4 An alternative method for determining the shear resistant characteristic, using the concept of field strength, is presented in Annex G. If the shear force Tough is determined by this Annex, and: 060

075

V

Rkt ≤ V ≤ Sd γ

V

Rkt γ

M M Rk ≤ M ≤ Rk Sd γ γ

must be verified interaction between bending moment and shear force by meeting the following expression: M M Where:

V Sd + 0625 Sd ≤ 1375 γ γ V Rk Rkt

59

γ is the weighting coefficient of resistance to bending, equal to 1.10;

Page 60 60

NBR 8800 - Based Text Revision M Sd and V Sd are requesting the bending moment calculation and shear strength requestor calculation, respectively; M Rk is the characteristic resistant bending moment determined under subsection F.2 Annex F; V is resistant to shear determined characteristic according to subsection G.1 Rkt Annex G.

5.4.3.3 Strength shear resistant feature in other cases 5.4.3.3.1 The shear resistant feature, V RkFor sections I and H flexed around the axis passing through the median plane of the soul, U sections flexed around the central axis of inertia parallel to the soul, solid circular and rectangular sections and circular tubular sections, is equal to: V= V Rk pl with V= pl

0 6 The f w y

Where: The w is the effective shear area, which should be taken equal to (A gross cross-sectional area):

the table and f is the area of ​ g the

a) sections in tables I, H and U symmetrical to the central axis of inertia perpendicular to the soul: 133 The; f b) in rectangular solid sections: c) in circular solid sections: d) in circular tubular sections:

067 The; g 075 The ; g 050 The . g

5.4.3.3.2 The shear resistant feature given in 5.4.3.3.1 assumes that the section does not has elements subject to local buckling by shear stresses, and the stresses of shear acting on elements of the section parallel to the axis of flexion, are inferior those who work in the elements perpendicular to this axis. 5.4.4 plates reinforcing the overlapping tables (lamellae) 5.4.4.1 When overlapping plates are used to tables with less than the length ranging from beam, they must extend beyond the section which theoretically would be unnecessary, called transition section. Such extension should be attached to the parent table by high strength bolts (connected by friction) or fillet welds, sized to a request calculation equal to the resultant of the normal stresses on the slide, caused by bending moment calculation requesting the transition section (Figure 11).

Page 61 NBR 8800 - Based Text Revision 5.4.4.2 Additionally, in case of welded lamellae, their longitudinal welds ends in the length 'should be sized to a request for calculation equal to the resultant of the normal stresses on the slide, caused by bending moment requestor calculating a section on the far 'end of the coverslip with a' (figure 11): a) equal to the width of the lamella, where there is continuous fillet weld, the nominal size (See 6.2.6.2) equal to or greater than 75% of the thickness of the lamella along the edges the same longitudinal length a 'and by its end; b) equal to 1.5 times the width of the slide, where there is a continuous weld fillet size Nominal (see 6.2.6.2) less than 75% of the thickness of the lamella along the edges the same longitudinal length a 'and by its end; c) equal to twice the width of the flap when there is no welding through its end, however, there are continuous fillet welds along their edges the longitudinal length '. Transition section

Overlying plate (lamella)

Diagram of bending moments b Transition section Extension beyond the transition section b Transition section a = b or b depending 1.5 nominal size of the fillet b Transition section a = 2b Figure 11 - Overlapping plates of the beams tables

61

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NBR 8800 - Based Text Revision

5.4.5 Additional requirements related to welded sections 5.4.5.1 The tables consist of welded beams can have varying thickness or width due to the splice plates in different sizes or use of lamellae. 5.4.5.2 In welded, the weld joining tables and soul must be designed to withstand the Total horizontal shear resulting from bending. The horizontal distribution of welds flashing should be proportional to the intensity of shear, however, the spacing Longitudinal can not exceed the maximum allowed for compressed or tensile bars, according to 5.2.9) and 5.3.6.2.3 respectively pulled and compressed to tables. In addition addition, the solder joining table and soul must be sized to transmit any force to the soul applied directly on the table, unless they make checks evidencing the transmission of such force only by contact. 5.5 prismatic bars subjected to a combination of axial force and moments bending and torsion This subsection shall apply to the verification of the ultimate limit states prismatic bars subject the combined effects of normal force and bending moment caused by static actions, with or untwisted, or subject only to torsion. Additionally, should be checked every state usage limits apply, as existing in various parts of this standard prescriptions. Sections 5.5.1 symmetrical bending and subjected to normal and oblique simple flexion and composed 5.5.1.1 5.5.1.2 In the condition appears to be met by prismatic bar whose section Cross having one or two axes of symmetry, subjected to the combined effects of strength normal and bending moment around one or both of the central axes of inertia loaded so no twisting occurs. The condition appears to be met in 5.5.1.4 for the purpose the cutting forces acting simultaneously along the central axes of inertia of the section cross. 5.5.1.2 Unless we make a more precise analysis of the interaction between the combined effects normal force of tension or compression and bending moments, the limitation must be obeyed provided by the following expressions of interaction: a)

for

N N

Sd ≥ 0 2 Rd

N 8 M Sdx, M Sdy Sd + + ≤ 1 0, N 9 M M Rd Rdx, Rdy b)

for

N N

Sd < 0 2 Rd

M M N Sdx, + Sdy ≤ 1 0, Sd + 2N M M Rd Rdx, Rdy Where:

Page 63 NBR 8800 - Based Text Revision

63

NSdrequestor is the normal force calculation traction or compression, whichever is applicable, determined according to 4.8; N is resistant to normal force calculation of traction or compression, whichever is applicable, Rd respectively determined in accordance with 5.2 or 5.3; M Sd, xand M Sd, yare the bending moments requesters calculate respectively around the x and y axes of the cross section, determined in accordance with 4.8; M Rd xand M Rd, yare resistant bending moment calculation, respectively around the x and y axes of the cross section, determined in accordance with 5.5.1.3. 5.5.1.3 The calculation resistant bending moments around the central inertia axes of x and y the cross section, respectively M Rd xand M Rd,Must y be determined according to 5.4, changing the values ​ of λ and λ for the limit state of local buckling of the soul towards flexion p r around the axis perpendicular (s) core (s) when the normal strength calculation requesting, N compression, as follows: a) value of λ p λ

p

= 376

h

p h

E f

1-

y

275 N Sd , for N γ y

N N

Sd ≤ 0125 γ y

or λ

h = 112 p p h

b) value of λ r for

E λ = 149 r f y

E f y 075 ≤

233 -

N N

Sd ≥ 149 E , for γ f y y

N N

Sd > 0125 γ y

h ≤ 150 h c

1 + 283

N h Sd 1h N γ c y

≤ 570

N E Sd 1 - 074 f N γ y y

Where: E is the modulus of elasticity of steel; f y is the yield strength of steel; h is the height of the soul, taken equal to the distance between inner faces of the profile tables soldiers and equal to that value minus the two rays of agreement between the table and the soul Rolled sections; hc is twice the distance from the center of gravity of the cross section to the inner face of compressed table in welded and equal to that value minus the fillet radius between table and soul in rolled sections;

Sd, Is

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NBR 8800 - Based Text Revision hp is twice the distance from the plastic neutral axis of the cross section for the performance only bending the inner face of the welded compressed time table is equal to this value less the fillet radius between table and soul in rolled sections; Ny is the normal compressive force corresponding to the flow cross section effective, given by the product ( Q The f ) And Q local buckling coefficient, g y determined in accordance with Annex E and A cross-sectional area; g gross γ is the weighting coefficient of resistance to compression, equal to 1.10.

5.5.1.4 For patients with normal flexion, checking the shear force should be taken as 5.4.3. For cases of oblique bending, should evaluate the need to consider superposition of the effects of shear forces requesters calculation that act on the axes center of inertia of the cross section. Sections 5.5.2 asymmetric bending and subjected to normal and oblique simple flexion and sections subjected to torsion, normal force, bending moments and shear 5.5.2.1 5.5.2.2 In the conditions to be met by prismatic bars are presented asymmetric section subjected to the combined effects of normal force and bending moment around one or both main axes of inertia of the section, so that load does not occur twist, and the prismatic bars subjected to torsion, bending moments, shear forces and normal force. 5.5.2.2 The resistant strain calculation, σ RdFor the ultimate limit states the following should be greater than or equal to the requesting voltage calculation expressed in terms of normal stress, σ shear stress, σ by the elasticity theory, using the Sd,Determined v combinations of shares calculation. Like this:

Sd,Or n

a) for the limit states of instability under the effect of normal stress: σ

Sdn,

≤

χf γ

y

b) for the limit states of instability under the effect of shear stress: σ

Sdv

≤

060 χ f γ

y

Where: γ is the weighting coefficient of resistance equal to 1.10; f y is the yield strength of steel; χ is a reduction factor associated with the compression strength determined according to = fσ λ = 060 f σ for voltages to normal stresses and the y and the y and shear with σ equal to the yield stress (normal or shear, which is and applicable) of elastic buckling, for the limit state of instability in question, 5.3.3, taking

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λ

NBR 8800 - Based Text Revision

65

taking into account, where relevant, the interaction between local buckling and global instability. 5.6 bars of varying section The calculation and design of bars of variable section must be made in accordance with Annex N. Tables 5.7 and souls of profiles I and H subjected to concentrated forces 5.7.1 General This subsection provides requirements for verification of ultimate limit states caused by concentrated forces between two stiff sections, applied to the external face of at least one of the tables, perpendicular to your face in sections I and H. The concentrated forces should be centered on the axis of the cross section passing through the plane of the soul. 5.7.2 Local Bending the table 5.7.2.1 The table of a bar, requested by a concentrated force producing traction on the soul, should be checked for ultimate limit state local bending. 5.7.2.2 The check presented only applies to concentrated force with length acting in the direction perpendicular to the length of the bar located between width of the loaded table. If the length of action of the force is less than check must be made.

015 b b, where b is the 015 b To

5.7.2.3 Unless the provisions in 5.7.2.5, the applicant concentrated force calculation can not γ Where / overcome the resistant force calculation of the bar table, equal to F γ is the coefficient Rkb weighting for local bending resistance of the soul, equal to 1.10, and F Rkbis the resisting force characteristic is given by: = 625 t 2 f F Rkb f y Where: t f is the thickness of the loaded table; f y is the yield strength of the steel. 5.7.2.4 When the concentrated force acts at a distance from the lower end 10 bar times the thickness of the table, the resistant force given in 5.7.2.3 should be halved. 5.7.2.5 If the concentrated force requestor calculation overcome the resistant force calculations shall be placed on the actuation force section, transverse stiffeners on both sides of soul, soldiers loaded the table and extending until at least half the height of the soul. The weld connecting transverse stiffeners to the soul must be sized to transmit the force eccentric relative thereto. 5.7.2.6 In the case of welded, the weld between the table and the soul should be able to forward tractive force between these two elements.

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5.7.3 Local Drain Soul 5.7.3.1 The Soul of a bar, requested by tension or compression caused by a force concentrated that acts on the table, should be checked for the ultimate limit state flow location. 5.7.3.2 Unless the provisions in 5.7.3.3, the applicant concentrated force calculation can not γ Where / overcome the resistant force calculation of the bar soul, equal to F γ is the coefficient RKW weighting for local flow resistance of the soul, equal to 1.00, and F is the resisting force RKW characteristic is given by: a) when the force is concentrated at a greater distance from the end of the bar height of the cross section: = (5 k + l ) f t F RKW n y w b) when the power is concentrated at a distance from the bottom edge or equal to the height of the cross section: = ( 2 5,k + l ) f t F RKW n y w Where: f y is the yield strength of steel; l n is the length of action of the force in the longitudinal direction of the beam; k is the thickness of the table loaded over the side of the weld bead parallel to the soul, the case of welded; the thickness of the table plus the fillet radius to soul, in the case of rolled profiles; t wis the web thickness. 5.7.3.3 If the concentrated force requestor calculation overcome the resistant force calculations shall be placed reinforcing plates of soul or placed on the actuation force section transverse stiffeners on both sides of the soul, extending until at least half the Cell height. If the force is tensile, the stiffeners are welded to the loaded table. If the force is compression, the stiffeners should be in perfect contact with the table charged or be welded to this table to impart strength to the soul. The solder connecting transverse stiffeners to the soul must be sized to convey the eccentric force relative to same. 5.7.3.4 In the case of welded and concentrated tensile force, the weld between the table and the soul must be able to transmit the force between these two elements. 5.7.4 Wrinkle soul 5.7.4.1 The Soul of a bar, requested compression caused by a concentrated force that acts on the table, should be checked for the ultimate limit state wrinkling.

Page 67 NBR 8800 - Based Text Revision 5.7.4.2 Unless the provisions in 5.7.4.3, the concentrated force acting calculation can not overcome γ Where / resistant force calculation of the bar soul, equal to F γ is the coefficient Rke

67

weighting of resistance to wrinkling of the soul, equal to 1.35, and F characteristic is given by:

Rkand is the resisting force

a) when the compressive force is concentrated at a distance from the end of the bar greater than or equal to half the height of the cross section:

= 080 t 2 1 + 3 F Rke w

l

n d

t t

w

15,

Ef t y f t w

f

b) when the compressive force is concentrated at a distance from the end of the bar less than half the height of the cross section: - To

l n d≤02 = 040 t 2 1 + 3 F Rke w

- To

l

n d

t t

w

15,

f

Ef t y f t w

l n d>02 = 040 t 2 1 + F Rke w

4l d

n - 02

t t

w f

15,

Ef t y f t w

Where: d is the height of the cross section of the bar; t f is the thickness of the loaded table; t wis the thickness of the soul; l n is the length of action of the force in the longitudinal direction of the beam. 5.7.4.3 If the concentrated force requestor calculation overcome the resistant force calculations shall be placed reinforcing plates or soul, placed in the action section that forces a a transverse stiffener side of the heart or transverse stiffeners placed both sides of the soul, in perfect contact with the loaded table or soldiers at this table, extending until at least half the height of the soul. The weld connecting the stiffeners Cross the soul must be sized to convey the eccentric force in relation to thereof. 5.7.5 Lateral Buckling of the soul 5.7.5.1 The Soul of a bar, requested compression caused by a concentrated force that operates in the compressed table, should be checked for the ultimate limit state buckling

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side, if the lateral relative displacement between the compressed table and loaded the table pulled is not prevented at the point of force application. 5.7.5.2 Unless the provisions of 5.7.5.3, 5.7.5.4 and 5.7.5.5, the force concentrated requestor γ/

calculation can not overcome the resistant force calculation of the bar soul, equal to FRkl the weighting coefficient of resistance to lateral buckling of the soul, equal to 1.20, and F strength resistant characteristic, given by: a) if the rotation of the loaded table is prevented, for

= F Rkl

(h t ) ( b ) ≤ 230 w l f

3 C t3 t h t r w f 1+ 0 4 w h2 l bf

b) if the rotation of the compressed table is not prevented to

= F Rkl

Where γ is Rkl it is

(h t ) ( b ) ≤ 170 w l f

3 C t3 t h t r w f 04 w h2 l b f

Where: l is the longer length unlocked laterally between the two tables involving section performance of the concentrated force; bf is the width of the table; t f is the thickness of the table; t wis the thickness of the soul; h is the distance between the inner faces of the radii of less tables in accordance case of rolled sections, or the distance between the inner faces of tables in the case of welded; M < M and 331 ×10 6 MPa when d r M ≥ M section of the force (F d requestor is the bending moment calculation and M r is d r bending moment corresponding to the onset of yield as Annex D without consider the residual stresses). Cr is equal to

662 × 10 6 MPa

when

(h t ) ( b ) exceed 2.30 or 1.70, respectively, when the rotation table 5.7.5.3 If w l f charged or is not obstructed, the ultimate limit state of lateral buckling of the soul has likely to occur. 5.7.5.4 If the rotation of the loaded table is prevented and concentrated strength calculation requestor overcome the resisting force calculation given in 5.7.5.2-a), a lateral restraint at the table pulled the actuation force section should be provided. Can optionally be placed in this section transverse stiffeners on both sides of the soul, in perfect contact with the loaded table or welded thereto, extending until at least half the height of

Page 69 NBR 8800 - Based Text Revision soul. The weld connecting the stiffeners to the soul must be sized to transmit the force between these two elements. Another alternative is the placement of reinforcing plates soul extending until at least half the height of the soul, which must be scaled to resist all of the concentrated force. 5.7.5.5 If the rotation of the loaded table is not prevented and the strength concentrated requestor calculation overcome the resisting force calculation given in 5.7.5.2-b), lateral restraints in both

69

tables section of action of the force should be provided. 5.7.6 Buckling of compression soul 5.7.6.1 The Soul of a bar, requested compression caused by a pair of forces concentrated opposite directions, acting in both tables of the same cross-section must be checked for the ultimate limit state buckling compression. 5.7.6.2 Unless the provisions in 5.7.6.4, the force concentrated requesting calculation (value of each under par) can not overcome the resistant force calculation of the bar soul, equal to F where γ is the weighting coefficient of resistance to buckling of the soul, equal to 1.10, and F is the resisting force characteristics, given by: = F Rkc

24 t 3 E f w y h

5.7.6.3 When the pair of concentrated forces located at a distance from the end of the beam less than half the height of the cross section, the resisting force should be given in 5.7.6.2 halved. 5.7.6.4 If the concentrated force requestor calculation overcome the resistant force calculations shall be placed reinforcing plates of soul, placed in the activity section that forces a a transverse stiffener side of the heart or transverse stiffeners placed both sides of the soul, in perfect contact with the loaded table or soldiers at this table, extending the full height of the heart. The weld connecting transverse stiffeners to the soul must be sized to transmit the force eccentric with respect thereto. 5.7.7 Shear in the web panel zone 5.7.7.1 Reinforcing Plates soul or diagonal stiffeners shall be provided within the outline of a rigid connection between beam and column (the area of ​ the column web panel), whose souls lie in the same plane when the shear strength calculation requester, γ Where / transmitted by the beam tables, F Exceeds the F γ is the resistance coefficient Sdv RKV flexion, equal to 1.10, and F RKV is the shear resistant feature, given by: a) when the effect of deformation of the column web panel zone of stability structure is not considered in the analysis: - To

F ≤ 04N Sdv lp = 060 f d t F RKV y c w

- To

>04N F Sdv lp

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NBR 8800 - Based Text Revision F = 060 f d t 1 4 - Sdv F RKV y c w N lp b) when the stability of the structure, including the plastic deformation of the panel zone the column web is considered in the analysis: - To

F

≤ 075 N

Rkc

γ ,/ Rkc

Sdv

lp

3b t2 = 060 f d t 1 + fc fc F RKV y c w d d t v c w -

for

> 075 N F Sdv lp

3b t2 fc fc = 060 f d t 1 + F RKV y c w d d t v c w

19-

1 2F Sdv N lp

Where: t is the thickness of the soul; w bfc is the width of the abutment table; t fc is the thickness of the abutment table; dv is the height of the cross section of the beam; dc is the height of the column cross section; f y is the yield strength of the pillar; Np is the normal compressive force corresponding to the flow section l Cross-pillar, without regard to local buckling, equal to

f The; y g

The the column cross section. g is the gross area of ​ 5.7.7.2 Reinforcing Plates soul, when used, must be properly welded to absorb the expected portion of the total shear force. 5.7.7.3 diagonal stiffeners, when used, must be connected to the column web with solder sized to resist the eccentric force transmitted by the beam. 5.7.8 ends of beams without restriction to rotation and soul free Transverse stiffeners should be used at ends of beams that have no type of restriction to rotation about the longitudinal and in which souls are not attached to shaft other beams or pillars. These stiffeners shall be welded to the tables and the soul section Cross, extending the full height of the soul.

Page 71 NBR 8800 - Based Text Revision 5.7.9 Additional Requirements for stiffeners to concentrated forces 5.7.9.1 The transverse and diagonal stiffeners must also meet the following requirements: a) the width of the stiffener added to half the thickness of the bar can not be soul less than one third of the width of the table or plate which receives the force connection concentrated; b) the thickness of the stiffener can not be smaller than half the thickness of the table

71

Bar or connecting plate that receives the concentrated force, and also can not be less 179 f E . its width multiplied by y 5.7.9.2 The transverse stiffeners used to prevent the occurrence of ultimate limit states related to the action of concentrated force, extending the full height of the soul, when Tablets must be compressed and scaled bar according to 5.3 for the ultimate limit state of instability by bending about an axis in the plane of the soul. The cross section is considered to be formed by stiffeners over a range of soul equal width 12 t If the stiffeners are end and equal to 25 t If they are in w w an inner section. The length of buckling should be taken equal to 075 h Where h is the Cell height. 5.7.9.3 The weld connecting the stiffeners to the soul must be sized to convey the excess shear stiffeners for the soul, when the stiffeners are not welded to the loaded table. 5.7.10 Use of reinforcing plates soul to concentrated forces Reinforcing plates of soul, always consisting of two plates placed next to the soul of both its sides must have a thickness and length allowing them to reach resistance necessary to prevent the occurrence of the ultimate limit state which led to their placement and be welded so as to absorb the expected portion of the concentrated force. 6 Specific conditions for the design of steel connections 6.1 General 6.1.1 Basis of design Metallic bonds consist of binding elements (stiffeners, connection plates, valances, corbels, etc..) and connecting means (welds, bolts, threaded rods and round pin). These components must be sized so that its resistance calculation a certain ultimate limit state is equal to or greater than the request calculation determined: (1) the analysis of the structure subjected to combinations of calculating shares, as 4.7; (2) as resistance of a specified percentage of the connected bar. In some specific situations, resistance calculation can also be based on limit state.

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NBR 8800 - Based Text Revision

6.1.2 Stiffness of the connections between beam and column 6.1.2.1 In the elastic structural analysis, a beam-column connection can be considered labeled if S ≤ 0 5,E I L ; can be considered as rigid if S ≥ 8EI L in the case of structures i v v i v v and indeslocáveis S ≥ 25 E I L in the case of movable structures (see 6.1.2.2). i v v Where: Si the rigidity of the connection is calculated from the rotation-time diagram, with the stiffness Drying corresponding to 2 3 /resistant bending moment calculation of the bond; I vL vare the moment of inertia of the cross section in terms of structure and length connected to the link, respectively beam;

E is the modulus of elasticity of steel. In any case, the analysis for elastic connection may be considered semi-rigid, with stiffness Si constant throughout the loading. For plastic analysis, the effect of the moment-rotation behavior of the connections can only be considered if it is possible to reproduce numerically the characteristics of nonlinearity of this behavior. It is recommended to consult for this type of analysis, bibliography specialized on the criteria for the classification of bonds, based on capacity and the resilient deformability thereof. 6.1.2.2 The limit

L can be used only for walk in which each floor is v v satisfy the relation K K ≥ 0 1 Where K is the average value I L / for all beams at the top v v p v v the floor and K p is the average value I / L for all the pillars of the floor (I v is the time to p p inertia of a beam in the plane of the structure I p is the moment of inertia of a pillar in the plane of structure G v is the will of a beam considered center-to-center pillars; and L p is the height of floor for a pillar). If

25 E I

S ≥ 25 E I L But i v v movable structures.

K

v

K < 0 1 , The connection should be considered semi-rigid to p

6.1.3 Bars with flexible connections at supports The flexible connections of beams and trusses can take into account only the reactions calculation compatible with the hypothesis of flexibility, unless otherwise indicated in responsible for the project. These flexible connections must allow rotation of beams simply supported at the ends; for it allows the consideration of deformations inelastic autolimitáveis ​ the link. Links with initial stiffness equal to or less than the lower limits of the expressions given in 6.1.2 may be considered as links flexible, disregarding the effects of the stiffness in the global response of the structure. 6.1.4 Bars with rigid or semi-rigid connections at the supports In determining the strength calculation of rigid or semi-rigid connections must be considering the combined effects of all internal forces calculation, from

Page 73 NBR 8800 - Based Text Revision total or partial stiffness connections, which may be considered rigid connections whose stiffness Home is less than the upper limits of the expressions presented in 6.1.2. 6.1.5 Minimum resistance of connections 6.1.5.1 To ensure structural integrity, the requirements of 4.9 must be met. For other situations, apply 6.1.5.2 and 6.1.5.3. 6.1.5.2 Connections subject to a request under 45 kN calculation, except for diagonal travejamento of composite bars, rods made of round bars and sleepers lateral closing of buildings, shall be designed for a calculation request equals 45 kN. 6.1.5.3 The connections of tensioned or compressed bars, and resist the normal forces Applicants for calculating the bar, must also be sized to equal the forces calculation

73

50%onofit.the resistance calculation of the bar to the types of normal force (tension or compression) that act 6.1.6 Bars efforts transmitting compressed by contact 6.1.6.1 To ensure structural integrity, the requirements of 4.9 must be met. For other situations, apply 6.1.6.2, 6.1.6.3 and 6.1.6.4. 6.1.6.2 pillar whose ends are machined for example by cutting with a saw to transmit compressive forces by contact, the end connections with plates support, or between pillars, must be made with bolts or welds able to keep their positions safely connected all parts. 6.1.6.3 Other compressed bars with machined ends, passing efforts by contact means and elements should be positioned in connection to keep all aligned parts of the connection and dimensioned to withstand 50% of the normal resistive force calculation connected bar. 6.1.6.4 In both previous cases, the said bonds shall be designed to resist also 100% the calculation requests that are not transmitted by contact, including cases of reversal efforts. 6.1.7 Prevention of rotation at the supports The points of support beams and trusses must be prevented from rotating around its axis longitudinal. 6.1.8 Layout of welds and bolts 6.1.8.1 Groups of screws or welds at the ends of any axially bar required, must have their centers of gravity about the axis passing through the center of gravity boom section, unless it is taken into account the effect of eccentricity. 6.1.8.2 In cases of simple valances or double bars and the like, applied axially is not required that the center of gravity of groups of fillet welds or bolts to rest on the baricêntrico axis of the bar at the ends thereof, for cases not subject to bar

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fatigue; eccentricity between the axis of the bar and the links can be neglected in bars applied statically, but must be taken into account in bars subjected to fatigue. 6.1.9 Combination of connecting means 6.1.9.1 bolts in combination with welds 6.1.9.1.1 In new construction, high strength bolts in connections per contact or common screws can not be considered working together with welds; welds, when used, shall be designed to resist the total requests calculation of connection. High-strength bolts in friction connections, properly installed, can be considered working together with welds. 6.1.9.1.2 In making changes in existing structures by welding, rivets and screws high strength (which are adequately tightened) can be considered existing to withstand the stresses due to the calculation of loads acting now. Requests due to new shipments must be resisted by reinforcing welds that are added to

connection. 6.1.9.2 High-strength bolts in combination with rivets In new or existing buildings, high-strength bolts in friction connections, installed in accordance with 6.7, can be considered working together with rivets. 6.1.10 lamellar fracture Should be avoided whenever possible, welded joints where transmission of stresses traction from shrinking welding performed under constraint conditions of distortion, is Knife through the planar element in a direction not parallel to the face (for example, L-joints or T). If it can not be avoided that kind of connection, precautions should be taken to prevent the occurrence of lamellar fracture. 6.1.11 Limitations of use for welded and bolted 6.1.11.1 welds or high strength bolts with initial prestressing should be used in following cases: a) amendments pillar structures with over 60 m in height (see 6.1.11.2); b) seams pillar structures with a height between 30 and 60 m, where the smaller horizontal is less than 40% of the time (see 6.1.11.2); c) amendment of pillar structures of less than 30 m tall, the lower case horizontal dimension is less than 25% of the time (see 6.1.11.2); d) connections of beams and trusses of which depends on the bracing system and links beams and trusses with pillars, structures with over 38 m in height (see 6.1.11.2); e) connections and splices roof trusses, truss connections with pillars, amendments pillars, pillars of bracing connections, connections or French hands corbels used for reinforcement of gateways, and media links parts of cranes, the structures with cranes with a capacity exceeding 50 kN;

Page 75 NBR 8800 - Based Text Revision f) connections supports parts of machinery or parts subject to impact loads or cyclical; g) any other connection that is specified in the drawings of the structure. 6.1.11.2 For purposes of paragraphs a), b), c) and d) of 6.1.11.1, the height of a structure must be considered as the vertical distance between the average level of the surrounding ground structure and top of the beams of the roof, in the case of flat roofs or less than 25% slope. On case of roofs with a slope greater than 25%, the vertical distance is measured between one middle and the upper face of the roof trusses at the half height of the sloping part. The garrets may be excluded in determining the height of the structure. 6.1.11.3 For cases not listed in 6.1.11.1, links can be made ​ with screws high strength, without initial prestressing, or with common screws. 6.1.12 Amendments of heavy sections Seams welded with tables or soul of a thickness exceeding 50 mm and profiles laminates with more than 44 mm thick tables, subject to tensile stresses due to

75

bending moment and normal force, must meet the following requirements: a) when the plates of the tables or soul are amended before forming the profile of accordance with the appropriate item of AWS D1.1, the relevant requirements of that standard apply in lieu of these requirements. If welds are used in slot full penetration to transmit tensile forces, the requirements of material toughness given in footnote 7) Table 8, details of the access opening for the welding data 6.1.13, requirements for preheating given in footnote 8) of the Table 8 and the requirements of surface preparation for flame cutting and inspection are given in 12.2.1.2 applicable. b) on all seams subjected to traction extenders and plates waiting for welding must be removed and the surfaces abraded to face milling. c) at all seams are subject primarily to the compression bars, openings access for welding necessary for the implementation of full penetration welds shall meet the requirements given in 6.1.13. Alternatively, such amendments, including cases of bars subjected to tension due to wind action, may be made by means of details not induce large deformation retraction; for example, slot welds partial penetration combined with seamless tables soul through splints and welds fillet, bolted splices, or combinations of bolts and fillet welds in seams with splints. 6.1.13 Scraps of beams table for connections and access openings for welding 6.1.13.1 All access openings required to facilitate the welding operation should have a minimum length of 1.5 times the thickness of the material in which the opening is made. The height should be adequate for proper deposition of weld metal and the adjacent plates should be provided for any extenders enough to weld the material space where the opening is made, but no less than the thickness of the material.

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NBR 8800 - Based Text Revision

6.1.13.2 Scraps of beams table for connections and access openings for welding should be free slots and reentrant corners. 6.1.13.3 In the case of welded with tables or soul of a thickness exceeding 50 mm and Rolled sections with thickness exceeding 44 mm tables, surfaces clippings beams and access openings for welding obtained by flame cutting, should be abraded to bright metal and inspected by magnetic particle or liquid penetrant before the deposition of seam welds. If the region transition curve of such clippings and openings is performed through drill or saw, this region does not need to be polished. 6.1.14 Considerations links with tubular profiles Many of the requirements of this section may not apply in part or in full the links involving one or more tubular profiles, which have unique characteristics of behavior. It is recommended for the design of these connections, becoming the adjustments necessary to maintain the level of security provided by this standard, the use of AWS D1.1 and the following publications: a) Wardenier, J.; Kurobane, Y.; Packer, JA; Dutta, D. & Yeomans, N. (1991) Design guide hollow section (CHS) joints under predominantly circular for static loading. Pour le Developpement International Committee et l'Etude de la Construction tubulaire (CIDECT). Verlay TÜV Rheinland. Germany.

b) Packer, JA; Wardenier, J.; Kurobane, Y.; Dutta, D. & Yeomans, N. (1992) Design guide for rectangular hollow section (RHS) joints under predominantly static loading. Pour le Developpement International Committee et l'Etude de la Construction Tubulaire (CIDECT). Verlay TÜV Rheinland. Germany. 6.1.15 Fatigue Connections subject to fatigue, see Annex M. 6.2 Solder 6.2.1 General 6.2.1.1 All provisions of AWS D1.1 for the welded joints not subject to fatigue, are applicable to the implementation of scaled structures in accordance with this standard. A only exception should be made to the provisions given in 6.1.13, 6.1.14, 6.2.2.2, 6.2.6.2 and Table 8 this Standard, which should be applied instead of AWS D1.1 items dealing with same subjects. 6.2.1.2 The length and arrangement of welds, including returns, shall be indicated on design drawings and manufacturing.

Page 77 NBR 8800 - Based Text Revision 6.2.2 Effective Areas 6.2.2.1 Solder Slot The following provisions shall apply: a) the effective area of ​ groove welds shall be calculated as the product of length effective thickness of the weld effective throat; b) the effective length of a weld notch is equal to its actual length, which should be equal to the width of the connected part; c) the effective throat of a slot weld full penetration shall be taken equal to smaller thicknesses of the welded parts; d) the effective throat of a weld notch partial penetration is indicated in the table 5; e) the effective thickness of the neck of a weld joints curved surface when the Soldering is flush with the surface of the bar is shown in Table 6. prove to that the effective throat of these welds is being taken regularly, should be made sampling of welds performed for each welding procedure; Samples be taken into random sections or perhaps in the sections indicated in the document Project. The use of larger throat thicknesses than indicated in the table is permitted

77

6, provided the manufacturer can demonstrate, through training, that these thicknesses can be obtained with greater regularity. The qualification consists of cutting the bar with curved surface, perpendicular to the axis of the half-length of the weld and the terminal ends of the weld. These cuts must be made to a number dimensions of combinations of materials in order to cover the range to be used for manufacturing, or as required by the responsible project. Table 5 - Effective throat thickness of the weld notch partial penetration Position welding

Welding process Electrical arc coated electrode (SMAW) 1) 2) Submerged arc welding (SAW) Electrical arc Shielding gas (GMAW) 3) Arc with flow in the core (FCAW) 4)

Throat thickness effective

Type chamfer

J-groove or U Depth chamfer

All

Bevel or bevel V-groove angle of ≥ 60 º chamfer 5) Bevel or bevel Depth V-groove angle of least 3 mm chamfer chamfer between 45 º and5) 60 º

NOTES: 1)SMAW - Shielded Metal Arc Welding 2)SAW - Submerged Arc Welding 3)GMAW - Gas Metal Arc Welding 4)FCAW - Flux Cored Arc Welding 5)Chamfer angle is the angle between the faces melting

Page 78 78

NBR 8800 - Based Text Revision Table 6 - Effective throat thickness of the weld joints curved surface Welding Type Opening the composite gasket a flat surface and curve Opening the composite gasket two curved surfaces

Radius (R) of the bar or Folding

Effective throat thickness

Any R

5 R / 16

Any R

R 2 1) /

Note: 1)Use 3R 8 for / the electric arc process with shielding gas (except in the transfer process by short circuit) when R ≥ 25 mm . 6.2.2.2 Solder Fillet The following provisions shall apply: a) the effective area of ​ a fillet weld should be calculated as the product of length effective thickness of the weld effective throat; b) the effective throat of a fillet weld shall be the shortest distance measured from the root to the face theoretical weld flat, except for fillet welds with orthogonal legs performed by submerged arc process when the effective throat can be increased by 3 mm, for fillet welds with greater than 10mm legs, and can be taken equal to the leg to solder Fillet equal to or less than 10mm legs. Leg of the fillet is the smaller of the two sides, located on the faces melting, the largest triangle that can be inscribed in the weld section.

Root of the weld is the intersection of the faces melting; c) the effective length of a fillet weld, except for the situations presented in d) and e) below, must be equal to the total length of the weld size uniform, including the returns at the ends; d) for longitudinal fillet welds in connections axially extreme elements requested, with a length exceeding 300 times the nominal size of the weld, the effective length should be taken as the total length of the weld multiplied the reduction factor β equal to 0.60, and the length is between 100 and 300 times the β is given by: nominal size of the weld, β = 12 -

0002

lw ≤ 1 0, b w

Where: l w is the total length of the weld; bw is the nominal size of the weld, given in 6.2.6.2. e) the effective length of a fillet weld in holes or tears must be measured at along the line joining the midpoints of the uniform effective throats points. If the area a fillet weld run in the hole or slot, calculated from this length,

Page 79 NBR 8800 - Based Text Revision is larger than the area given in 6.2.2.3, then the latter should be used as an effective area the fillet weld. 6.2.2.3 Welding of buffer holes or tears The effective shear area of ​ a solder cap, hole or tear, must be equal to the area Nominal cross-section of the hole or tear in the plane of the surfaces in contact. 6.2.3 Combination of different types of solders If a single link two or more types of welding (notch fillet buffer are used holes or slots), calculation of the resistance of each of these types must be determined and separately to the axis of said group in order to determine the resistance of calculating the combination. However, this method of composing individual resistances of welds shall not apply to welds the overlapping slot fillet welds, shall be used in the calculations only resistance of the latter. 6.2.4 Requirements for the weld metal and welding procedures 6.2.4.1 Table 7, extracted AWS D1.1, are presented base metals and welding electrodes that can be used in pre-qualified welding procedures. See also 4.1.1 of AWS D1.1: 2002. 6.2.4.2 For specifications for pre-qualified welding procedures, including preheat temperatures and interpasses See Section 3 of AWS D1.1: 2002. 6.2.4.3 For other qualifying welding procedures, see Chapter 4 of AWS D1.1: 2002.

79

6.2.5 Resistance calculation 6.2.5.1 The resistance calculation, R Rd, Given by the ratio between the characteristic resistance R Rk and weighting coefficient γ of resistance of various types of solder, is shown in Table 8. In this table, the MBis the theoretical area of ​ the face melting, The the weld,yfis lower w is the effective area of ​ flow resistance between the metal base of the joint ef the minimum tensile strength of w weld metal, obtained from Table A.4 in Annex A. In any situation the weld strength can be made greater than the resistance of the base metal.

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NBR 8800 - Based Text Revision Table 7 - Compatibility with the base metal of the weld metal Metal base ABNT

ASTM

NBR 6648 (CG-24 A36 - (t ≤ 20 mm) t ≤ 20 mm) A500 Grade A NBR 6648 (CG-26 A500 Grade B A570 Grade 40 t ≤ 20 mm) 6649 NBR (CF-24)A570 Grade 45 I 6649 NBR (CF-26) 6650 NBR (CF-24) 6650 NBR (CF-26) Group NBR 7007 (MR 250 t ≤ 20 mm)

1), 2)

Metal solder compatible Arc Arc with electrode Submerged arc protected lined gas (SMAW) (SAW) (GMAW) AWS A5.1 AWS A5.17 AWS A5.18 E60XX, F6XX-EXXX, ER70S-X, E70XX F6XX-ECXXX, E70C-XC, F7XX-EXXX, E70C-XM 5)AWS A5.5 F7XX-ECXXX (Except-GS) X-E70XX 5)5)AWS A5.23 AWS A5.28 F7XX-EXXX-XX,ER70S-XXX, F7XX-ECXXX-XX XXX-E70C

Arc with the flow core (FCAW) AWS A5.20 E6XT-X E6XT-XM, E7XTX E7XT-XM (except 2-2M, -3, -10, -13, And GS-14 and except 11 thickness more than 12 mm)

5)AWS A5.29 E6XTX-X E6XT-XM E7XTX-X E7XTX-XM 5000 NBR (G-30) A36 (T> 20 mm) A5.17 AWS A5.18 - AWS A5.20 AWS A5.1AWS E7015,F7XX-EXXX, 5000 NBR (G-35) A570 Grade 50 ER70S-X, E7XT-X E7016,F7XX-ECXXX E70C-XC, NBR 5004 (F32/Q32) A570 Grade 55 E7XT-XM E7018, NBR 5004 (F35/Q35) A572 Grade 42 E70C-XM (Except -2,-2M, E7028 5)NBR 5008 (ClassesA572 Grade 50 AWS A5.23 (Except-GS) 3, -10, -13, and -14 I 1, 2 and 2A A572 Grade 55 F7XX-EXXX-XX, GS and except -11 5)A5.5 I t ≤ 100 mm) 5)- thickness 4) 4) AWS F7XX-ECXXX-XX AWS A5.28 A588 (T ≤ 100 mm) E7015-X 4) ER70S-XXX, more than 12 mm) NBR 5920 A913 Grade 50 E7016-X 4) XXX-E70C NBR 5921 A992 E7018-X Group 5)AWS A5.29 NBR 7007 (AR-290) NBR 7007 (AR-345) E7XTX-X E7XTX-XM NBR 7007 (AR-COR 4) 345 A or B) NBR 8261 (Grade B and C) 5)5)5)- AWS A5.29 5)A913 Grade3) 60 AWS A5.5 AWS A5.23 AWS A5.28

II I

A913 Grade3) 65

E8015-X E8016-X E8018-X

F8XX-ECXXX-XX F8XX-EXXX-XX, XXX-E80C ER80S-XXX, E8XTX-XM E8XTX-X

Group 1) together consist of different groups of base metals, solder metals may be used consistent with the base metal higher resistance or lower resistance, one should use low hydrogen electrodes for second option. Preheating should be based on the group of greatest resistance. 2) When performed stress relieving welds the weld metal can not contain more than 0.05% vanadium. 3) The limitations of item 5.7 of AWS D1.1: 2002, related to the heat input, do not apply to ASTM A913, and 60 degrees 65. 4) A special welding processes and materials needed (eg electrodes, low alloy E80XX X) to meet characteristics of atmospheric corrosion resistance and impact resistance of the base metal - see section 3.7.3 AWS D1.1: 2002. 5) Metal welding of B3, B3L, B4, B4L, B5, B5L, B6, B6L, B7, B7L, B8, B8L, B9, groups or any degree BXH in AWS A5.5, A5.23, A5.28 and A5.29 are not prequalified.

Page 81 NBR 8800 - Based Text Revision Table 8 - Elements of Arithmetic Welding Type

81

Rk/ γ welds

Request type and orientation Traction or compression parallel to axis of weld

Resistance calculation R γ /1) 2) 4) Rk Same as the base metal

Traction or compression perpendicular to the effective γ = 110 5) 7) R =section Thef and Rk w y solder Slot welds full penetration 8) Shear (vector sum) in the effective section

Traction or compression parallel to axis of weld3)

Slot welds partial penetration8)

Normal tensile effective section of the weld

The smaller of the two values: a) Metal base and γ = 110 R Rk= 060The wf y b) Weld Metal γ = 125 R = 060Thef and Rk ww Same as the base metal The smaller of the two values: a) Metal base γ = 110 and R Rk= 060The wf y b) Weld Metal and γ = 125 RRk= 060The wf w

Compression perpendicular to the effective section of Same the weld as the base metal

Fillet welds

Welding of buffer holes or tears

Shear parallel to the axis of the weld, in the section Weld metal 6) and γ = 135 RRk= 060The effective wf w Traction or compression parallel to axis of weld3) Same as the base metal Shear on effective section (a request calculation is equal to the resultant vector of all Weld metal 6) calculating the joint forces that produce tensions 9)and γ = 135 RRk= 060The wf w normal or shear contact surface from related parties) Weld metal 6) Shear parallel to the surfaces in contact, the γ = 135 R = 060Thef and effective section Rk ww

NOTES: 1)For definition of effective areas of welds see 6.2.2.

2)The solder metal to be used for each base metal is given in Table 7. 3)Fillet welds and groove welds partial penetration, linking the elements of welded (Tables and souls), can be calculated without considering the tensile or compressive these elements, parallel to the axis of the weld; should be considered, however, the shearing stresses caused by forces Cutting and local effects. 4) In welds subject to non-uniform stresses, the request of calculation and the resistance calculation will be determined based on unit lengths effective. 5)In this case, when two types of strength of the weld metal in table 7 can be used only class greater resistance. 6)The base metal shall meet the requirements in 6.5.2 and 6.5.3. 7)For corner joints, and T, with plate waiting not removed from the weld, the weld metal should have a Minimum tenacity of 27 J at 4 ° C in Charpy test V-Notch can dispense with the requirement of tenacity since the gasket is sized using the weighting coefficient of resistance and characteristic strength of a partial penetration weld. The same requirement applies to toughness welded seams welded with thick table and / or greater than 50 mm soul and rolled profiles with more than 44 mm thick tables (in this case there is no alternative to waive such a requirement). 8) In welded seams welded with thick table and / or greater than 50 mm soul and profiles laminates with thickness exceeding 44 mm tables, a preheating exceeding be applied 175 ° C. 9)See also 6.2.5.2.

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NBR 8800 - Based Text Revision

6.2.5.2 For calls made ​ with a group of fillet weld located in the same plane and shares subject to this plan, with the resulting actions through the center of gravity of group of fillets, the resistance characteristic R can be determined by: Rk R

Rk

=06 f

w

Σ The 1 +( 0 5,sen 15,θ ) wi i i

Where: i is the number associated with each thread group; The w f ware defined in 6.2.5.1; θ is the angle between the resultant of the actions and the longitudinal axis of the thread in question. 6.2.6 Limitations 6.2.6.1 Solder Slot The minimum thicknesses of effective throats of welds are partial penetration groove indicated in Table 9. dimension of the weld should be established according to the part more thick welded, except that such size need not exceed the thickness of less thick, since the resistance of calculation required is obtained. For this exception and that to obtain a good quality welding, special care must be taken using preheating. Partial penetration welds can not be used in splices flexed parts. Table 9 Minimum effective throat thickness of a slot weld penetration partial Greater thickness of the base metal joint (mm) Below 6.35 and up to 6.35 Over 6.35 to 12.5 Over 12.5 up to 19 Over 19 up to 37.5

Minimum thickness of the throat Effective (mm) 1) 3 5 6 8

Over 37.5 up to 57 Over 57 up to 152 Above 152

10 13 16

Note: 1)See 6.2.2 for the definition of effective throat. 6.2.6.2 Solder Fillet 6.2.6.2.1 The minimum nominal size (size of the leg) of a fillet weld is given in 10 table, according to the thickest part welded, except that, in the case of links between table and Soul welded, this dimension need not exceed required to develop resistance calculation of the soul. For this exception and to obtain a good weld quality, special care should be taken may be necessary to use preheating.

Page 83 NBR 8800 - Based Text Revision Table 10 - Minimum size of a fillet weld Greater thickness of the base metal joint (mm) Below 6.35 and up to 6.35 Over 6.35 to 12.5 Over 12.5 up to 19 Over 19

Minimum nominal dimension of 1)(Mm) fillet weld 3 5 6 8

Note: 1)Performed only with a pass. 6.2.6.2.2 The maximum nominal size (size of the leg) of a fillet weld that can be used along the edges of welded parts is as follows: a) along edges of material with thickness less than 6.35 mm, no more than material thickness; b) along edges of material with thickness less than 6.35 mm, no more than the thickness of the material minus 1.5 mm unless the drawings that solder is indicated as enhanced during execution, in order to obtain the total thickness desired throat .. 6.2.6.2.3 The minimum effective length of a fillet weld (see 6.2.2.2), scaled to a solicitation of any calculation, can not be less than 4 times its nominal size or then this nominal size can not be considered more than 25% of the effective length the weld. Additionally, the effective length of a fillet weld subject to any request calculation can not be less than 40 mm. When only longitudinal fillet welds are used in extreme link bar tensile boring, the length of each fillet may not be smaller than the transverse distance among them. See also the provisions in 5.2.5.2. 6.2.6.2.4 Intermittent fillet welds may be used, sized to convey requests calculation when calculating the resistance required is less than a weld Continuous nominal size of the smallest allowed, and also to connect bar elements composed. The effective length of any segment of intermittent fillet weld not

83

may be lessrequires than fourspecial times the or less than 40 dimension. The use of welds intermittent carenominal with local buckling andmm corrosion. 6.2.6.2.5 The minimum overlay in overlay connections, should be equal to 5 times the thickness of the connected part less thick and not less than 25 mm. Plates or bars connected by superposition only and subject to transverse axial loading fillets, welds must be fillet along the edges of both parties, except when the deformation of the Overlapping is sufficiently contained to prevent opening of the connection effect of requests calculation. 6.2.6.2.6 Terminations fillet welds may extend until the end or until the edges of related parties, or disrupted near these sites, contour or form a closed, except as limited below:

Page 84 84

NBR 8800 - Based Text Revision a) Joints by superposition in which one party extends beyond an edge subjected to longitudinal tensile stresses, the threads must be stopped at a distance this edge not less than the size of the leg of the fillet; b) for connections and structural elements with normal cyclical forces in the elements projection, frequency and magnitude that would tend to cause progressive fatigue from a point at the end of the weld, solder fillets should bypass the corners, extending a distance not less than twice the size of the leg or width of the connected party, whichever is less; c) for connections whose project requires flexibility of elements in projection, if Used returns at the ends of the threads, the length of the returns is not exceed four times the size of the leg; d) fillet weld connecting transverse stiffeners welded to the souls should be interrupted at a distance from the intersection of the surface of the solder composition profile with the soul no less than four times nor more than six times the thickness of the soul, except when the end of the stiffener is welded to the table; e) fillet welds on opposite sides of a common plan must be stopped at the corner Common to both welds.

6.2.6.2.7 fillet welds may be used in holes or slots to transmit shear forces to contact surfaces in connections to prevent buckling or superposition (or separation) of overlapping parts and for connecting section bars compound. For such solders the provisions of 6.2.2.2 shall be met. The fillet welds in holes or tears can not be regarded as solders buffer. 6.2.6.2.8 fillet welds may be used with angle between the faces melting understood between 60 º and 120 º, provided there is contact between the welded parts across a flat surface (And not just an edge). For other angles can not be regarded as the solder structural; therefore, it is inappropriate for broadcast efforts. 6.2.6.3 Welding of buffer holes or tears Welds buffer can be used in holes or tears to transmit shear forces to contact surfaces in connections to prevent buckling or superposition (or separation) of overlapping parts and for connecting section bars compound. The diameter of the holes for welding of buffer holes can not be less than the thickness of the part containing the

greater than 8 mm and not greater than 2.25 times the thickness of the weld. The center-tocenter-hole solder buffer must be equal to or greater than 4 times the hole diameter. The length of solder tearing buffer slots can not be greater than 10 times the weld thickness. The width of the slots can not be less than the thickness of the part containing the greater than 8 mm and not greater than 2.25 times the thickness of the weld. The ends of these Tears should be semicircular or shall have not less rounded corners radius to thickness of the part containing them, except those ends which extend to the edge of element soldier. The spacing between the centerlines of tears, measured in the direction transverse to the length of the slots should be equal to or greater than 4 times the groove width. The center-to-center slots located on the same longitudinal line the length of thereof measured on this line should be equal to or greater than 2 times the length of the Tears. The thickness of solder cap into holes or tears located in thick materials

Page 85 NBR 8800 - Based Text Revision equal to or less than 16 mm should be equal to the thickness of the material. When the thickness of the material is greater than 16 mm, the thickness of the weld shall be at least equal to half the same material thickness, but not less than 16 mm. 6.3 Bolts and threaded round bars The requirements of this standard refer specifically to ordinary bolts ASTM A307 and high strength bolts to ASTM A325 and A490, with UNC thread. However, allows the common use of ISO 898 Class 4.6 bolts and bolts of high-strength ASTM A325M, ASTM A490M, ISO 898 and ISO 898 Class 8.8 Class 10.9, since for these screws, all demands made for Similar ASTM screws are met, with the mutatis mutandis. Are also provided round bar threaded, the threads must meet the requirements of ASME B18.2.6 with Class 2A tolerance; nuts of round bars must be the same threaded bar material and should have dimensions as specified ASME B18.2.6 for hex nuts. 6.3.1 High-strength bolts In bolted with high strength bolts requirements of connections must be met subsection 6.7. All high strength bolts must be tightened in order to develop a force minimum prestressing, given in Table 16 and obtained as 6.7.4.1, except as follows, where it is assumed the normal grip: a) connections per contact in which the slip is allowed; b) ASTM A325 bolts subject to tension or draw and cut when no fluctuations loading causing fatigue or loosening the screws. It is considered that normal tightening can be obtained by some to be a key impact impact or the maximum effort of a worker using a normal key, always ensuring firm contact between related parties. Screws mounted uncontrolled initial prestressing shall be clearly indicated in the design drawings, fabrication and assembly. 6.3.2 Areas of calculation 6.3.2.1 Effective Area for contact pressure The effective area and contact pressure of the screw is equal to the diameter of the screw multiplied the plate thickness considered. Screws with countersunk head are not covered by this

85

Standard. 6.3.2.2 Effective Area of ​ bolt or threaded round bar, to draw The tough area or effective area of ​ a screw or a threaded round bar (The be) To Traction is a value between the gross floor area and the root area of ​ the thread. This standard this area is considered equal to 0.75 A b, Where Ab gross floor area, based on the diameter of the bolt or outer diameter of the thread of threaded round bar, d b. In short: A= be

075 The b

Page 86 86

NBR 8800 - Based Text Revision With: π The = d 2 b 4 b

6.3.3 Resistance Calculation in connections per contact 6.3.3.1 General The resistance calculation, R Rd, The screws should be determined by the relationship between resistance characteristic, R And the weighting coefficient of resistance, γ. In determining the Rk request of computation for bolts subject to tension, in addition to external stresses must be taken into account the leverage effect, if any, and exclude the prestressing force due to tightening the screws. The additional tensile force caused by the leverage effect in the case of standard holes can be given by:

T Q=

Sd

d

b 2 d the+ b 2

b-

en 2f

y 444

≥0

Where: TSdrequestor is the traction force calculation on the screw without leverage; t is the smallest thickness t

1 et 2 connected plates (Figure 12);

f y is the lowest flow resistance of the plates connected (the process does not apply if the value of f y the lower plate is greater than the thickness of the thicker plate); bea are the dimensions shown in Figure 12 (if

a> 125 b , Should be useda = 125 b );

db is the diameter of the bolts; p is the tributary width of the screw, is the sum of the effective widths of each side of the bolt, defined as (figure 12): - Effective width between two screws: the lesser of

and/ ( ) 2andb + ( 0 5,d ) ; 1 b

- and Effective + ) (2andbwidth ( 0 5,between d ) ; end screw and the plate edge: the lesser of b If both p-values ​ shown in Figure 12 are different, use the lowest value. T +.Q Sd

The pulling force of total calculation, the screw is equal to

If the thickness t is less than t mingiven below, this thickness is insufficient; the connection shall be changed and recalculated the value of Q:

Page 87 NBR 8800 - Based Text Revision

t

min

=

87

b -( 0 d5 ) b p- d h fp 1 + y p

444 T

Sd

where dh is the diameter of the hole. Pd

the b

The

and 2 and 1

The

TSd+ Q

TSd+ Q

Q

lower among (E2) And (b + d 0.5 b) p p

and 1 t1

Q

b the

lower among (E1/ 2) and (b + d 0.5 b)

t2 and 2

Pd Figure 12 - Leveraging In the specific case of links to moment with top plate, requests traction in Screws may be determined alternatively, according to the model of the hinges plastic, adopted by Eurocode 3, Part 1.8 (View Joints in Steel Construction: Moment Connections, SCI / BCSA, 1995), mutatis mutandis. To bolted plates with 6.5.4 Filling see links. 6.3.3.2 Traction The resistance calculation pulled with a round bar and a threaded end Screw pulled, both with a diameter exceeding 12 mm, is given by γ = 135 and R Where:

Rkt

= The f be ub

R

Rkt

γ Where /

f ub is the tensile strength of the material of the bolt or threaded round bar tensile specified in Annex A; The beis the effective area, defined in 6.3.2.2. In the case of the round bars threaded R bar off the thread by flow resistance f

y.

Rktmust exceed the product of the area of

Page 88 88

NBR 8800 - Based Text Revision

6.3.3.3 Shear The calculation of shear strength of a bolt or threaded round bar equals γ Where / γ = 135 (Must also be satisfied in the above 6.3.3.4 and 6.3.5): R RKV - For high strength bolts and threaded round bars, when the cutting plane passes through the thread; common screws in any situation R

= 0 4 Thef RKV b ub

- High strength bolts and threaded round bars, when the cutting plane does not passes through the screw R

= 0 5,Thef RKV b ub

Where: f ub is the tensile strength of the material of the bolt or threaded round bar tensile specified in Annex A; The b is the gross floor area, based on the diameter of the bolt or threaded round bar, d in 6.3.2.2. The values ​ of resistors features are related to only one cutting plane. 6.3.3.4 contact pressure in boreholes The resistance of calculating the contact pressure on the wall of a hole, already taking into account the tear strength between two consecutive holes or between one end and the hole edge is γ Where / γ = 135 and (must also be satisfied in the above 6.3.3.3 and 6.3.5): given by R Rkc a) in the case of hole pattern, enlarged holes, little holes stretched in any direction and very elongated holes in the direction of the force: - When the deformation of the link to service requests is a consideration project R

=1 2 l ft ≤ 2 4 d ft Rkc c u b u

- When the deformation of the link to service requests is not a design consideration R

= 1 5,l ft ≤ 3 0,d ft Rkc c u b u

b) in the case of many holes elongated in the direction perpendicular to the force:

bGiven

R Where:

= 1 0,l ft ≤ 2 0,d ft Rkc c u b u

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89

f u is the tensile strength tensile steel; l c is the free distance in the direction of the force, between the edge of the hole and the edge of the adjacent hole or the edge of the connected part; db is the diameter of the screw; t is the thickness of the connected part. The use of extended holes and little holes or very elongated in the direction of force is restricted to friction connections (see 6.3.4). The total resistance is the sum of the resistances calculated contact pressure for all holes. In bolted at the ends of beams of souls connections, sized just for effect of shear strength calculation requestor V Sd (Without taking into account the moment due to eccentricity), this shear force should be considered not only as to their actual direction also perpendicular to this direction, to take into account the possibility of tearing of soul between hole and edge. 6.3.3.5 Tensile and shear combined When a bolt or threaded round bar is subjected to the simultaneous action of tensile and shear, in addition to checking for two isolated efforts as 6.3.3.2, 6.3.3.3 and 6.3.3.4 must also be met the requirements of Table 11. Table 11 - Tensile and shear force combined

Binding medium

Additional limitation of the resistance value By calculation tensile bolt or bar threaded round R

ASTM A307 bolts

ASTM A325 bolts

ASTM A490 bolts Round bars Threaded general

Rkt

/ γ ≤ 073 f

ub

The - 190 V b Sd

/ γ ≤ 073 f The - 190 V ub b Sd R / γ ≤ 073 f The - 150 V Rkt ub b Sd

1)

/ γ ≤ 073 f The - 190 V ub b Sd R / γ ≤ 073 f The - 150 V Rkt ub b Sd

1)

R

R

Rkt

Rkt

R

Rkt

NOTES: 1)Cutting plane passing through the thread. 2)Cutting plane does not pass the thread.

/ γ ≤ 073 f

ub

The - 190 V b Sd

2)

2)

Table 11:

Page 90 90

NBR 8800 - Based Text Revision f ub is the tensile strength of the material of the bolt or threaded round bar specified in Annex A; The b is the gross floor area, based on the diameter of the bolt or threaded round bar, d in 6.3.2.2;

bGiven

VSd is the shear force in the plane of calculation considered the bolt or bar round threaded. 6.3.4 Resistance calculation of high-strength bolts in friction connections The project calls for friction with high strength bolts should be done as 6.3.4.1 and 6.3.4.2 and must still meet the 6.3.3 and 6.3.1. 6.3.4.1 Checking for shearing force calculation γ Must / 6.3.4.1.1 Resistance calculation of a screw to slip R be equal rke1 and up to the shear force acting in the same calculation. The characteristic resistance, R Is Rke1 given by: R

Rke1

= 113 μ T N b s

Where: Tb is the minimum prestressing force per bolt, given in Table 16; Ns is the number of slip planes; μ is the mean coefficient of friction, defined as follows: - 0.33 for class A surfaces, that is, laminated surfaces clean and free from oils or greases, unpainted; - 0.50 for class B surfaces, ie sandblasted surfaces unpainted; The minimum area of ​ contact surfaces that must be unpainted is shown schematically in Figure 13. Surfaces classes A and B can also be blasted and painted, since the Average coefficient of friction is proven by tests according to requirements of the "Specification for Structural Joints Using ASTM A325 or A490 Bolts "; other values ​ of μ can also be established on the basis of such trials. - 0.35 for Class C surfaces, ie, hot galvanized surfaces with increased manually by wire brush roughness (not allowed use of machines).

Page 91 NBR 8800 - Based Text Revision

Area perimeter contact Circular area around hole Areas unpainted db or 25 mm (whichever is greater) dh db or 25 mm (whichever is greater) Area with paint allowed

Figure 13 - Surface contact unpainted The weighting coefficient of resistance, γ, is equal to: - 1.00 for standard holes; - 1.20 for extended or slightly elongated holes; - 1.45 for holes very elongated cross request to stretching the hole; - 1.65 for holes with very elongated request toward the hole stretching. Wedges with a maximum thickness of 6 mm, still containing elongated holes up to a ledge ("Shims finger"), as shown in figure 14, can be used in friction connections with standard holes, keeping the weighting coefficient of resistance equal to 1.00.

Figure 14 - Mounting plates with elongated holes to an edge

91

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NBR 8800 - Based Text Revision

6.3.4.1.2 When a frictional connection is subjected to tensile force N SdWhich reduces the force γ Given / prestressing, slip resistance, R in 6.3.4.1.1 should be Rke1 multiplied by the following factor: 1-

N

Sd 113 T n b b

Where: NSdis the design value of the tensile strength that prompts the screw; Tb is the minimum prestressing force per bolt, given in Table 16; nb is the number of bolts that support the force N

Sd.

6.3.4.2 Checking for shearing force characteristic 6.3.4.2.1 resistance for calculating a slip the bolt is given by

R

the weighting coefficient of resistance, γ is equal to 1.00 and the characteristic resistance R R

Rke2

Rke2

γ Where / Is: Rke2

= F The v b

Where: F is the characteristic shear resistance using friction, given in Table 12; the v F values v the table are based on Class A surfaces with friction coefficient μ = 033 (For other types of surface, the value of F v be obtained by trials). The d in 6.3.2.2. b is the gross floor area, based on the diameter of the screw, bGiven Table 12 - Resistance characteristic shear connections in friction, F (Each cutting plane)

Screw type

Hole pattern

ASTM A325 ASTM A490

117 145

vIn megapascals

Very elongated holes Holes and expanded Perpendicular little holes Parallel to to the direction of elongated direction of force force 103 124

83 103

69 90

6.3.4.2.2 When a frictional connection is subjected to a pulling force, which reduces the strength of γ Given / prestressing, slip resistance, R in 6.3.4.2.1 must be multiplied Rke2 by the following factor: 1Where:

N

Sk 080 T n b b

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93

NSkis the characteristic value of the tensile strength that prompts the screw; Tb is the minimum prestressing force per bolt, given in Table 16; nb is the number of bolts that support the force N

Sk.

6.3.5 Dimensions and use of holes 6.3.5.1 The maximum dimensions of holes shall conform to that indicated in Table 13, however, Larger diameter holes can be used in support pillars plates to take into account tolerances leasing anchors in concrete bases, using washers specially sized for such a situation. 6.3.5.2 In bolted connections between bars should be used standard holes, unless it is responsible for the project approved by the use of extended or elongated holes. 6.3.5.3 In connections with extended or elongated holes connection types should be observed and allowed limits given in Table 14. Table 13 - Maximum dimensions of holes for bolts and threaded round bars Bore bolt or bar threaded round db

the etr nsões andILIM m Dim in

Page 94

Diameter hole standard

Bore hole extended

≤ 24

d + 1 5, b

d +5 b

27

28.5

33

≥ 30

d +8 b d + / 16 3 b

A hole size slightly elongated d ( + 1 ) ×5 d ( + ) 6 b b 28 × 5, 35

A hole size very elongated d ( + 1 ),×52 5,d b b 28 × 5, 67 5,

of ga and nsões andlthe

≤ 7 8/

d + 1 5, b d + / 16 1 b

1

1 / 16 1

11 4/

d ( + 1 ),×5 d ( + 9 ), 5 d ( + 1 ),×5 2 d5 b b b b d ( + / 16 1 ) × d ( + / 1 ) 4 d ( + / 16 1 ) × 2 5,d b b b b 1 / 16 1 × 1 / 16 5 1 / 16 1 ×2 1 2 /

Dim p

≥11 8 /

d + / 16 1 b

d + / 16 5 b

d ( + / 16 1 ) × d ( + / 3) 8 d ( + / 16 1 ) × 2 5,d b b b b

94

NBR 8800 - Based Text Revision Table 14 - Limitations on the use of extended or elongated holes Type hole Extended

Type link permitted Friction

Friction Little bit elongate By contact

Friction

Very elongate

By contact

Limitations Hole Position In any or all link plates In any or all connecting plates. Any position regardless of direction of the request In any or all link plates. More dimension normal to the direction of request

Washers 1) Hardened over extended holes plates in external link About slightly elongated holes in External link plates should washers be used; such washers must be hardened when bolts are high strength.

Washers plate or flat bars continuous, structural steel, In only one of the parties minimum thickness of 8mm and binding to the same surface hole pattern should be used Contact. Any heading, on very elongated holes in regardless of the direction of external plates. Such washers or request bars should have dimensions sufficient to fully cover The elongated holes after installation of bolts. When In only one of the parties is necessary to use washers binding to the same surface 1)), These hardened (see 6.7.4.2 and Contact. Larger those normal to the direction of the request will be placed on washers plates or bars Continuing

Note: 1) When screws are used ASTM A490 greater than 25.4 mm diameter holes or elongated in expanded, the external link plates, hardened washers should be used in accordance with ASTM F436, However, the minimum thickness of 8 mm instead of the standard washers. 6.3.6 Handle long and very long bonds Except in cases of high strength bolts, fitted with initial prestressing, when the length exceeds handle 5 d the required number of screws or round bars b Threaded should be increased by 1 for each additional 1.5 percent mm handle (d diameter of the screw or threaded round bar). When connections contact, used in amendments tensile bar, have a length exceeding 1270 mm in the direction of external force, the shear force requestor calculation, V Sd, The bolts and the request calculation used to verify the contact pressure in boreholes shall be multiplied by 1.25 to taking into account the non-uniform distribution of the external force by the screws.

b is

6.3.7 Minimum spacing between holes The distance between centers of standard holes, extended or elongated, may not be less than rather

3,dwhere d b

b screw diameter round bar or screw.

2 7d , b

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95

Beyond this requirement, the clear distance between the edges of two consecutive holes can not be lower ad b. 6.3.8 Minimum distance from one hole to the edges 6.3.8.1 Standard Holes The distance from the center of a standard hole to any edge of a connected part can not be less than the value shown in Table 15, in which d b is the screw diameter or round bar threaded. Extended or elongated holes 6.3.8.2 The distance from the center of an extended or elongated hole at any edge of a connected party did not may be less than the value specified for standard holes, given in Table 15, plus βd b being db screw diameter and β defined as follows: -

β = 0 for holes elongated in the direction parallel to the edge considered;

-

β = 012 for enlarged holes;

considered;

β = 020 for holes slightly elongated in the direction perpendicular to the edge

β = 075 holes to very elongated in the direction perpendicular to the edge considered (the length of the elongated hole is much lower than that given in Table 13, the βd product can be reduced by an amount equal to half the difference between the b length given in the table and the actual length). Table 15 - Minimum Distance Diameter d b Inch

Millimeter

1/2 5/8 3/4

16

7/8

20 22 24

1 1 1/8

27 30

1 1/4 > 1 1/4

36 > 36

1) the center of a hole pattern to the edge Edge cut with saw or scissors (Mm) 22 29 32 35 38 3) 42 3) 44 50 53 57 64 1.75 d b

Or rolled edge cut the torch (Mm) 19 22 26 27 29 31 32 38 39 42 46 1.25 d b

NOTES: 1)Inferior to the table distances are permitted provided that the equations apply to 6.3.3.4 are met. 2)In this column, the distances can be reduced by 3 mm, when the hole is at a point where the request calculation does not exceed 25% of the resistance calculation. 3)At the ends of ledges connecting beams and end plates for flexible connections, this distance can be equal to 32 mm.

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6.3.9 Maximum spacing between holes and maximum distance from one hole to the edges

2)

6.3.9.1 For any edge of a connected part, the distance from the center of the screw (or bar Round Threaded) closest to that edge may not exceed 12 times the thickness of the part considered connected or 150 mm. 6.3.9.2 The maximum spacing between bolts connecting one plate to a profile or other plate in continuous contact, shall be determined as follows. a) on elements not subject to corrosion, painted or not, the spacing may not exceed 24 times the thickness of the thinnest part connected or 300 mm; b) for elements of atmospheric corrosion resistant steel, unpainted, the spacing can not exceed 14 times the thickness of the thinnest connected part, or 180 mm. 6.4 Pins 6.4.1 General The bending moments on a pin must be calculated assuming that the contact stresses between the pin and the connected parts are uniformly distributed throughout the thickness each part. If the pin passes through plates with a thickness greater than half the diameter of the pin, one should take into account the variation of the contact stresses through the thickness of plates and the bending moments are determined at pin according to this Distribution tensions. 6.4.2 Resistance calculation 6.4.2.1 Resistance of calculating flexural γ Where / Resistance calculation pin the bending moment is given by M the coefficient Rk weighting the resistance, γ is equal to 1.10 and the characteristic resistance M Rkis: M

Rk

=12 W f

y

where W is the elastic modulus of the resilient pin section f Pin material.

y is the flow resistance

6.4.2.2 Resistance of calculating the shear force γ Where / The resistance of calculating the shear pin is given by V the coefficient Rk weighting the resistance, γ is equal to 1.10 V and the characteristic resistance Rkis: V= Rk

060 The f w y

where Aw is the effective area of ​ the shear pin section, equal to 0.75 A Gross pin ef is the yield strength of the material of the pin. y

g, Where Ag is area

Page 97 NBR 8800 - Based Text Revision 6.4.2.3 Resistance to crushing calculation γ Where / Resistance calculation pin crushing is given by R the coefficient Rk weighting the resistance, γ is equal to 1.35 and the characteristic resistance R is:

97

R

Rk

= 1 f5 Rk y

where fy is the yield strength of the material of the pin. The request of calculation to be considered is the maximum contact stress calculation for uniform distribution or not. 6.5 Connection elements 6.5.1 General This subsection shall apply to the design of connection elements, such as: stiffeners, connecting plates, angles, consoles and all parts of the connected parts, locally affected by the binding. 6.5.2 eccentric Links Axes passing through the centers of gravity of the cross sections of axially bars and are applied in a node should preferably intersect at a common point. Otherwise, should be taken into account the time and the shear force due to eccentricity on the link. 6.5.3 Elements of calculation 6.5.3.1 General Rule All connecting elements (including the affected parts of bars) must be dimensioned γ Corresponding / so that their resistance calculation R to each applicable limit state, Rk is greater than or equal to the respective requests calculation. Particular attention should be given in the sizing of joints to avoid All possible types of buckling in the connection region. For serviceability limit states disposing of gross section and rupture of the net section, the stresses acting calculation, determined based on combinations of shares for calculating (or the strength requirements minimum link) and based on the effective resistance regions (net areas can not be taken greater than 85% of the corresponding gross areas), may not exceed resistance following calculation: a) for the disposal by normal stresses γ = 110

R

Rk

=f

y

b) for the flow of shear stresses γ = 110

R

Rk

= 0 f6 y

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NBR 8800 - Based Text Revision c) to damage by normal stresses γ = 135

R

Rk

=f

u

d) to disruption by shear stresses

γ = 135

R Rk = 0 f6u

where fy is the yield strength f

u the tensile strength of the material tensile strength.

In welded joints, tension calculation in the binding elements in the zone adjacent to the weld, can be determined by inverse proportion to the thickness of the base metal and (s) throat (s) Effective (s) of the weld, provided that such tensions be contained in the elements through thickness thereof. In checking rupture of flange plates must be used effective net area when applicable, as stated in 5.2. 6.5.3.2 Breakdown by tearing Collapse by tearing out is a state in which the resistance is determined by the sum of resistance to shear on a fault line and tensile strength in a segment perpendicular. Should be checked with the connections at ends of beams with table cropped to fit and in similar situations, such as tensile bars and gussets (Figure 15). When the tensile breaking strength of the net section is used to determine the resistance of a segment, the outflow of gross shear section is used in perpendicular segment and vice versa. The resistance of calculating the collapse is given by tearing by R Rk/ Γ, where γ is the weighting coefficient of resistance equal to 1.35 and R Rk is the resistance characteristic is given by: f The ≥ 0 f6 The u nt u nv

a) when R

Rk

f The < 0 f6 The u nt u nv

b) when R

= 0 [ f6,The + f The ] ≤ 0 [ f6,The + f The ] y gv u nt u nv u nt

Rk

= [ 0 f6 The + f The ] ≤ [ 0 f6 The + f The ] u nv y gt u nv u nt

Where: The gv is the gross area subject to shear; The gt is the gross area subjected to tension; The nv is the net area subject to shear; The nt is the net area subject to tension. In situations like those shown in Figures 15 and e-15-f, the superposition of high values ​ of normal and shear the base metal adjacent to the weld stresses in the plates A and B,

Page 99 NBR 8800 - Based Text Revision respectively, necessitates the application of a criterion for determining the resistance equivalent voltages; however, alternatively, one can determine the tension in the calculation regions of base metal adjacent to the weld, multiplying the stresses resulting from the calculation in welding per second (For / t plate A) and 2a/2t The B (For sheet B), considering the tensions thus obtained as shear, regardless of its direction, being aa effective throat of the weld fillet.

99

The t

The v

The t

The t

The v

The v (B)

(A)

The v

The

The t

(C)

t

⇒

t The

The B

(D)

(E)

(TThe etBare thicknesses of)

t

B

(F)

Figure 15 - Examples of collapse by tearing 6.5.4 Filling Plates 6.5.4.1 In the welded connections, any filler plate thickness equal to or greater than 6 mm must extend beyond the edges of the connecting plate and be welded to the part where it should be fixed, enough to transmit the force acting on the calculation sheet solder connection, eccentric load applied to the surface of the filler plate (Figure 16). Welds that connecting the connection plate to the plate filler should be sufficient to impart the strength of calculation that acts on the connecting plate and be of sufficient length so that it is not calculating overcome the resistance of the plate filler along the edge of the weld. When the thickness of the filler is less than 6 mm, the edges must coincide with the edges of the connecting plate and the size of the leg of the weld bead should be equal to sum of the size of the leg needed to transmit the force acting on the calculation sheet connection with the thickness of the filling (Figure 17).

Page 100 100

NBR 8800 - Based Text Revision 3

2

1

3 May be used

2

1

transverse welds along edges indicated Figure 16 - Filling with thickness exceeding 6 mm plate t < 6 mm 2

1

2

1

May be used transverse welds along edges indicated

t Effective dimension Real size Figure 17 - filler plate with a thickness of 6 mm 6.5.4.2 When filling plates with standard holes are used in bolted connections, and Such plates have a sum T s thickness not exceeding 6 mm, the resistance calculation shear bolts may be used without reduction. If t exceeds 6 mm, must meet s one of the following requirements: - When t s is equal to or less than 19 mm, the resistance calculation of shear bolts (And crush) on contact connections shall be multiplied by the factor 1 -[ 00157 t ( - 6)] , Where ts taken in millimeters; s - Filling the plates should extend beyond the bonding material, and that extension must have enough screws to distribute the total force that acts on the number support element, uniformly over the section of this combined support element and filling (see Figure 18);

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101

- Instead of the extension, may be added in the link, a number of screws equivalent to that provided in b) (see Figure 18 in which the forces in groups screws correspond to the resulting contact forces applied on the screws plates). Screws required if there was no filler Screws F1 force F1

F

F1

F

F

t1(Thickness of the filler) F1

F2

t2 (Thickness of the support element)

Alternative lengthening of binder material

F F + F = And F1 = 1 2 t 1

F2 t 2

Figure 18 - Plate filling in bolted 6.6 contact pressure 6.6.1 Resistance to contact pressure The resistance calculation, R Rk/ Γ, the surfaces in contact depends on the various forms and conditions such areas as indicated in 6.6.2 to 6.6.5. 6.6.2 Machined Surfaces In machined surfaces, including the case of ends for fitting with stiffeners contact with the table and the case pin through mandrilados or drilled holes, one takes the weighting coefficient of resistance, γ, equal to 1.35 and the characteristic resistance crushing, U.S. , Equal to: Rk R

Rk

= 1 8 Thef

y

Where: A is the contact area (projected area where pins); f y is the lowest flow resistance of the parts in contact. 6.6.3 not machined surfaces In non-machined surfaces, the pressure transmission to be done by weldment. To determine the resistance of calculation see 6.2 and 6.5.

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NBR 8800 - Based Text Revision

6.6.4 Apparatus massive cylindrical support on flat surfaces machined The resistance of calculating the contact pressure apparatus cylindrical solid support on Machined flat surfaces to be obtained using the weighting coefficient of resistance, γ, equal to 1.35 and a crush strength characteristic of the cylinder, R Rk, Equal to: - Is R

d ≤ 635 mm

1 2 f ( - σ) l d y Rk 20

- Is

=

d> 635 mm 6 0, f ( - σ ) l

dd

R Rk =

y

20

aux

Where: d is the diameter of the cylinder; f y is the lowest flow resistance of the parts in contact; σ = 90 MPa (With proper conversion when another unit); l is the length of the cylinder; d

aux

= 25 4 mm (With proper conversion when another unit).

6.6.5 Contact pressure on concrete supports The resistance of calculating the contact pressure in the area 1 the area under the load bearing plates, is determined using the weighting coefficient of resistance, γ equal to 1.65 (the request calculation shall be expressed in terms of compressive stress). The characteristic resistance, R Rk, Assuming that, on the face opposite to that of the concrete in contact with the backplate, the pressure is distributed across the face area and such that the distance between opposite sides is the largest of the three main dimensions of concrete block, is given by (Figure 19) a) when the concrete surface extends beyond the support plate and its outline is homothetic with respect to the charged region: R

Rk

= 085 f

Where:

The 2 ≤ 170 f ck The ck 1

f ckis the characteristic compressive strength of concrete; The 1 is loaded under the bearing plate area;

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103

The the concrete; 2 is the surface area of ​ b) when the contours are not homothetic, the R value Rk can be determined by above expression, however, the area A shall be calculated as shown in Figure 19. 2

The

The The 1

Area charged Homothetic Outline relative to the 1

Plant Load The loaded area

1

≥2 1 The 2 Section AA Figure 19 - Pressure contact on concrete supports 6.7 Design, assembly and inspection of connections with high strength bolts 6.7.1 General 6.7.1.1 This subsection refers to the design, assembly and inspection of connections made ​ with high strength bolts ASTM A325 and ASTM A490. 6.7.1.2 Connections to reassign forces parallel to the contact surface of the parties can be connected frictionally or, alternatively, by contact. The connections in which slip is highly harmful and those that are subject to repetitive forces with sign reversal should be friction.

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NBR 8800 - Based Text Revision

6.7.2 Bolts, nuts and washers 6.7.2.1 The bolts shall be in accordance with the current specifications of ASTM A325 "Standard specification for structural bolts, steel, heat-treated, 120/105 ksi minimum tensile strength ", or ASTM A490" Standard specification for heat-treated steel structural Bolts, 150 ksi minimum tensile strength. " The ASTM A325 specification provides for three types of high strength bolts, one with atmospheric corrosion resistance comparable to ASTM A588 steel. The responsibility for the project must specify the type of screws to be used. For requirements relating to the use of ASTM A325 galvanized bolts, see ASTM A325; ASTM A490 bolts can not be galvanized. 6.7.2.2 The dimensions of the screws shall be in accordance with the current specifications ASME B18.2.6 for heavy structural bolts, hex head. The length of bolt should be such that, after installation, its end coincides with or exceeds the face outer nut; This is necessary to provide a clearance in the calculation of length, so compensate for the tolerances of the bolt and the implementation structure. 6.7.2.3 The dimensions of the nuts shall be in accordance with the current specifications of ASME B18.2.6 for heavy hex nuts.

6.7.2.4 other types of fasteners may be used, provided they meet the requirements for material, manufacturing process and constant chemical composition of ASTM ASTM A325 or A490, that meet the requirements of mechanical properties of these same specifications, with evidence for full-scale testing, and also having stem diameter and the contact areas under the head and nut, or its equivalent, of not less values ​ corresponding to the requirements of 6.7.2.2 and 6.7.2.3 for a bolt and nut same nominal dimensions. The installation methods and inspection may differ from the indicated respectively in 6.7.4.3, 6.7.4.4, 6.7.4.5 and 6.7.5; in this case, such methods should be documented by detailed specification, subject to the approval of the engineer responsible for Project. 6.7.2.5 The circular washers and square beveled washers shall be accordance with the latest specifications of ASTM F436 "Standard Specification for Hardened Steel Washers. " The dimensions of the washers are specified in ASME B18.2.6. 6.7.3 Bolted Parts 6.7.3.1 hardened beveled washers shall be used to compensate for the lack of parallelism, when one of the outer surfaces of bolted parts have more than 1:20 slope in relative to the normal to the axis of the screw plane. The bolt parts of the structure can not be separated by any materials other than structural steel, and must be fully contact when assembled. The holes can be punched, subpuncionados and extended, or drilled. 6.7.3.2 When assembled, all the connection surfaces, including adjacent to the head screws, nuts and washers, shall be free from lamination scales (except those firmly adhered to the material), burrs, dirt or other foreign matter that prevent perfect contact between the parties. 6.7.3.3 The contact surfaces in friction connections shall meet the above in 6.3.4.1.

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105

6.7.4 Install the screws 6.7.4.1 Strength minimum prestressing tightening The high-strength bolts must be tightened so as to obtain a minimum strength prestressing (Tb) Appropriate to each type and diameter of screw used independently of the link be friction or contact, except in situations referred 6.3.1. This prestressing force is provided in Table 16 for the screws and ASTM equivalent to approximately 70% of characteristic tensile strength of the bolt, given in 6.3.3.2. The grip should be applied by the rotation of the nut, the calibrated wrench, or direct indicator traction method (see 6.7.4.3, 6.7.4.4 and 6.7.4.5). Table 16 - Minimum Force in prestressing bolts ASTM Diameter d b Inch 1/2 5/8

Tb (KN)

Millimeter

16 3/4

ASTM A325

ASTM A490

53 85 91 125

66 106 114 156

20 22 7/8 24 1 27 1 1/8 30 1 1/4 36 1 1/2

142 176 173 205 227 267 250 326 317 475 460

179 221 216 257 283 334 357 408 453 595 659

If necessary, depending on the conditions of access to the screw and the clearances for handling tool, the grip can be given by turning the bolt head and preventing the nut from rotating. When impact wrenches are used, their capacity should be adequate and its supply Air should be sufficient to obtain the desired tightening of each bolt approximately 10 seconds. 6.7.4.2 Washers In addition to the requirements 6.7.3.1 and table 14, hardened washers must be used in the following situations: a) under the turning element (nut or screw head) during fastening, where A490 screws tightened by rotating the nut and method in the case of screws A325 A490 calibrated or tightened with the key (that is, torque control); b) in which the element does not rotate during tightening, in the case of A490 bolts, when the element is based on a structural steel with lower resistance to flow 280 MPa .

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6.7.4.3 Tightening by the rotation of the nut method When using the method of tightening by turning the nut to apply the prestressing force specified in Table 16, there must be sufficient minimum number of screws provided pre-torque, to ensure that the parties are in full contact. The condition of pre-torque is defined as the tightness obtained after a few impacts applied by an impact wrench, or the maximum force applied by a worker using a normal key. After this operation initial, screws should be placed in the remaining holes and screws also led to such pre-torque condition. All connecting bolts should then get a grip Further, through the rotation of the nut applies, as indicated in Table 17, which must begin operation in the most rigid part of the connection and proceed toward the free edges. During this operation, the opposite side to that which applies in the rotation can not rotate. 6.7.4.4 Key Grip with calibrated When calibrated keys are used, they must be adjusted to provide a prestressing at least 5% higher than the minimum prestressing given in Table 16. keys must be calibrated at least once per working day for each bolt diameter to install. They should be recalibrated when significant changes are made to the equipment or when noticed a significant difference in the surface of bolts, nuts and washers. Calibration should be done by tightening three typical bolts of each diameter, removed Lot of bolts to be installed in a device capable of indicating the real draw in screw. For calibration must be certified that during the installation of bolts in the structure,

calibration doesgreater not produce a rotation of in theTable nut or17. bolt head from the are used to position of chosen pre-torque, than that indicated manuals If keys torque wrench, when torque is reached the nuts should be tightening move. During the installation of several screws on the wire, those already tight previously should be tested with the key and tightened if they "loose" during the handshake subsequent bolts, until all bolts reach the desired tightness.

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107

Table 17. Rotation of the nut from the pre-torque position Provision of the outer surfaces of bolted parts Length Screw (measured from bottom of the Head to the end) Less than or equal to 4 diameters Over 4 diameters up to a maximum of 8 diameter, including Over 8 diameters no later than 12 diameters 2)

Both sides normal to the axis of screw

One of ordinary faces the axis of the screw and another inclined face not more than 1:20 (No beveled washer)

Third back

Half back

Half back

2/3 back

2/3 back

5/6 back

Both sides inclined to the plane normal to the no screw shaft more than 1:20 (without beveled washers) 2/3 back 5/6 back

1 back

NOTES: 1)The rotation of the nut is considered in relation to the screw, without regard to the element being rotated (nut or bolt). To install with 1/2 turn or less screws, tolerance in the rotation is more 30 or less, screw installed with 2/3 turn and more, the tolerance on the rotation is more or less 45th. 2)No research has been done to establish the procedure to be used for tightening the rotation of the method nut to wavelengths greater than diameters screws 12. Therefore, the required rotation should be determined by tests on a suitable device that measures strength, simulating the actual conditions.

6.7.4.5 Tightening by using a direct indicator of traction It allowed tighten screws by using a direct indicator of drift, since it can be demonstrated for an accurate method of direct measurement, the screw was subjected to the force minimum prestressing given in Table 16, after tightening. 6.7.4.6 Reuse of bolts The A490 bolts and galvanized A325 bolts can not be reused. The other A325 bolts may be reused once, if an engineer's approval responsible. The tightening screw is tightened and that previously loosen during tightening screws neighbors is not considered as reuse. 6.7.5 Inspection 6.7.5.1 The inspector shall ensure that, for all the work, the requirements of 6.7.2 are met, 6.7.3 and 6.7.4. The inspector shall have free access to monitor the calibration switches as prescribed in 6.7.4.4. 6.7.5.2 The inspector shall observe the installation of bolts to determine if the procedure clamping was chosen being followed properly and should verify that all screws are tight. Bolts tightened by rotating the nut method can achieve protentions substantially higher than those recommended in Table 16, but are reason for rejection.

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6.7.5.3 When using the method of direct indicator of drift, the inspector should observe the installation of bolts to determine whether the tightening procedure that is approved being used properly and should verify that the correct tensioning was achieved according to the table 16. 6.7.5.4 When there are differences of opinion as to the results of the inspection force obtained by the method of prestressing rotation of the nut or calibrated key, the next inspection arbitration shall be used unless another procedure has been specified: a) the inspector must use a key inspection with a torque wrench; b) three screws of the same type, diameter (whose length is representative Screws used in the structure) and conditions of those under inspection shall be placed individually in a calibration device capable of indicating the tension in screw. The under surface of the part to be rotated during tightening of each screw must be equal to the corresponding surface of the structure, that is, there must be a washer under part turning if washers are used in the structure, or, if these are not used, the material adjacent to the part that spins must be of the same specification of the corresponding material in structure; c) each bolt specified in b), must be tightened in the calibration device by any convenient method to reach an initial condition with approximately 15% of the amount of prestressing required for the bolt in the table 16 and then up to the value of that prestressing. Tightening given after the initial condition may not result in rotation greater than that permitted in Table 17 nut. A key inspection should then be applied to the screw was tightened and should be given the necessary torque to rotating the nut or head 5 degrees in the direction of tightening. The average torque obtained from the trials of three screws should be taken as torque inspection of the work to be used in the

manner specified in paragraph d) below; d) screws as represented by the sample obtained in b), and have been tight structure, must be inspected by applying, in the tightening direction, the switch inspection and its corresponding torque inspection of the work; This should be done at 10% bolts, but not less than two randomly chosen on each link. If no nut or bolt head spin by applying torque inspection work, the connection should be accepted as properly tightened. If any nut or head screw by turning torque application inspection, this torque should be applied to all bolts connection and all bolts whose nut or head spin by applied torque inspection of the work should be tightened and reinspected or alternatively, the manufacturer or assembler, your choice, you can tighten all screws on the link, resubmetendo it to the specified inspection. 7 Specific conditions for the design of steel-composite elements concrete 7.1 The mixed steel-concrete structural elements provided by this standard are beams, columns and slabs. 7.2 The dimensions of the steel-concrete composite beams must be done in accordance with the requirements of Annex Q.

Page 109 NBR 8800 - Based Text Revision 7.3 Sizing of steel-concrete composite columns must be done in accordance with the requirements of Annex A. 7.4 The dimensions of the steel-concrete composite slabs must be made ​ according to the requirements of Annex S. 8 Specific conditions for the design of composite joints The design of mixed steel-concrete connections must be made according to the requirements of Annex T. 9 Additional Considerations resistance 9.1 General In addition to the requirements of sections 5, 6, 7 and 8, other aspects of resistance must be considered under certain conditions, among which are: fatigue, puddling, brittle fracture and elevated temperatures. 9.2 Fatigue 9.2.1 Bars and connections subject to the effects of fatigue should be sized according to the requirements of Annex M. 9.2.2 Rarely bars or links in non-industrial buildings need to be scaled to fatigue, since the variations in the structures of action of these buildings occur only one small number of times during the useful life or produce only small voltage fluctuations.

109

9.2.3 The and occurrence peak effects in buildings, or However, earthquake, is of littlebrackets cranes frequency does notofdeserve considerations of wind fatigue. structures and machines are often subject to fatigue conditions. 9.3 puddling When the slope of a roof or floor of a building subject to receipt of water rain is less than 3%, further checks must be made to ensure that no occur structural collapse caused by the dead weight of accumulated water by virtue of the arrows of closure and structural components (see 11.6) materials. 9.4 brittle fracture In some situations the links and details are subject to triple states traction caused by notches, residual stresses, etc.. especially at low temperatures, fracture may occur fragile. To avoid this type of boundary condition, it is necessary that the design be used intrinsically ductile details. Abrupt transitions should be avoided, residual stresses excessive and excessively thick welded materials. 9.5 High temperatures The structures of steel and must be mixed, if necessary, scaled to the effects high operating temperatures or accidental origin (such as fires). In this

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latter case, the sizing should be done in case of fire according to NBR 14323. 10 Additional conditions of project 10.1 General Should be included in the design considerations regarding contraflechas, protection corrosion of steel components and durability. 10.2 Contraflechas 10.2.1 The contraflechas as necessary should be indicated in the design drawings. Generally, the trusses span less than 24 m, contraflechas should be applied approximately equal to the arrow resulting from direct permanent characteristic actions. For beams bearing go less than 20 m, generally should be given equal contraflecha the arrow resulting from direct permanent features 50% more shares of stock variables characteristics. Any other contraflechas, for example, needed for compatibility deformations of the structure with the elements finish the work, shall be determined the specific cases treated. 10.2.2 The beams and trusses that are detailed without indication contraflecha should be constructed so that small deformations resulting from the manufacture or rolling, face up after assembly. If the application of contraflecha require the structure element is mounted under strain imposed by external means, it should be shown on the assembly drawings. 10.3 Corrosion on steel components 10.3.1 The steel components of the structure shall be designed to tolerate corrosion or must be protected against corrosion that can affect your strength or your performance of the structure.

10.3.2 Protection against corrosion in non-resistant steels to atmospheric corrosion can be obtained by protective layers, or other effective means, either alone or in combination. Corrosion resistant steels should also be protected when it is not guaranteed to training the protective film or when the thickness loss expected during the useful life is not tolerable. Alternatively, an adequate for corrosion can be used for expected life for the building and the aggressiveness of the medium. 10.3.3 The localized corrosion is likely to occur when there is retention of water condensation excessive, or caused by other factors, should be minimized by design and detailing appropriate. Where necessary, efficient water drainage should be provided. 10.3.4 If the protection specified for structures exposed to weather corrosion, or other environments where corrosion can occur gradually, requiring maintenance or renewal during the life of the structure (see 10.4), thus protected, the steel should have a Minimum thickness of 5 mm (excluding steel formwork of steel-concrete composite slabs, wedges plates and filling).

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10.3.5 The internal environment of buildings, conditioned for human comfort can be generally considered as non-corrosive. However, the need for protection against corrosion should be evaluated in each case and, if necessary, this protection should be given. 10.3.6 Protection against corrosion on the internal surfaces of parts whose interior is permanently sealed against the penetration of external oxygen is considered unnecessary. 10.4 Guidelines for durability 10.4.1 The steel and composite structures must be designed and constructed so that under the environmental conditions at the time of the project, and when used as recommended in design, retain the security, stability and fitness in service during the period corresponding to its life. 10.4.2 For the design life means the time period during which keep the characteristics of the structures, since it met the requirements of use and prescribed maintenance by the designer and the builder, as well as implementing the necessary repairs resulting from environmental damage. 10.4.3 The concept of life applies to the structure as a whole or its parts. Thus, certain parts of the structure may deserve special consideration with lifetime value all different. 10.4.4 To ensure that the structure maintains its characteristics during life project, the steel elements, including the members of the joint structures should be adequately protected against corrosion (see 10.3), and any other factors of aggressiveness, when this is necessary, and that such protection must undergo an inspection process periodic. Pieces of concrete and your equipment, members of the joint structures should obey related to the durability requirements of ISO 6118. 10.4.5 Depending on the size of the building and the aggressiveness of the environment and in possession of project information, materials and products used and the execution of the work should be produced by a qualified professional user information, inspection and maintenance. This manual should specify clearly and objectively the basic requirements for use and

preventive maintenance necessary to ensure the expected service life for the structure. 11 limit states 11.1 General The occurrence of a limit state can impair the appearance, the possibility of maintenance, durability, functionality and comfort of the occupants of a building, as well as it can cause damage to equipment and finishing materials linked to the building. 11.2 Basis for Project 11.2.1 The limits to be imposed on the behavior of the structure values, and ensuring their Full use should be chosen taking into account the functions assigned to the structure and materials related to it. 11.2.2 Each limit state should be checked using combinations of actions of use (see 4.7.3) associated with the type of response studied.

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11.3 Shifts 11.3.1 The structure of the displacement bar and sets of structural elements, including floors, roofs, partitions, exterior walls, etc.., may not exceed the values limits set out in Annex C. 11.3.2 The lateral displacements of the structure and the horizontal relative movements between floors, due to combinations of actions to use (see 4.7.3) can not cause collision with adjacent buildings, nor exceed the limit values ​ laid down in Annex C. 11.4 Vibrations 11.4.1 Beams restraints floors of large areas that do not have partition walls or other forms of damping, transient vibrations due to which people may be walking unacceptable should be dimensioned taking into consideration this type of vibration, as Annex W. 11.4.2 Mechanical equipment that may produce undesirable continuous vibration should be insulated to reduce or eliminate the transmission of such vibrations to the structure. Vibrations of this type should be taken into account also in the verification of limit states past, including fatigue. Other sources of continuous vibration are vehicles and activities human such as dance. See Appendix W for limit states and Annex M to fatigue. 11.4.3 For vibrations due to wind, see Annex X. Vibrations of this kind should be taken into account also the verification of the ultimate limit states, including fatigue (see Annex B, subsection B.4 and Annex M). 11.5 Dimensional Changes Measures should be taken so that the dimensional variations of a structure and its elements, due to temperature variations and other effects do not affect the use of structure. 11.6 puddling of water on roofs and floors

11.6.1 All roofs and floors of buildings subject to the receipt of rain water, less than 5% slope, should be checked to ensure that water will not be accumulate in puddles. This finding should be taken into account possible inaccuracies constructive and settlements of foundation, arrows of closing materials and components Structural including the effects of contraflecha. 11.6.2 Contraflechas beams can contribute significantly to prevent puddling, as well as the placement of exit points of water in adequate number and positions. 11.7 Cracking of concrete 11.7.1 In composite beams, tensile stresses in the concrete slab can cause cracks that undermine the protection of armor for corrosion or adversely affect the appearance or the use of the building.

Page 113 NBR 8800 - Based Text Revision 11.7.2 The related control requirements of the cracks that may occur in conditions cited in 11.7.1, are in Annex U. 12 Manufacturing, assembly and quality control 12.1 General 12.1.1 Documents Project All project documents must meet the minimum requirements of section 4. 12.1.2 standardized symbols and nomenclature Indicative welding symbols used in the drawings and inspection requirements of the structure must comply with the AWS Standards. 12.1.3 Changes in project The changes that are necessary in the project, during the stages of manufacture or assembly of the structure shall be made only with the permission of the head of the project, Relevant technical documents should be corrected consistently with those modifications. 12.2 Manufacture of structure and paint factory 12.2.1 Manufacture 12.2.1.1 desempeño material 12.2.1.1.1 Prior to its use in manufacturing, laminated materials must be straightened within the tolerances of supply. If these tolerances are not being met, it is allowed to perform corrective work by the use of controlled heating and / or straightening mechanics, subject to the limitations of this standard. Heating and mechanical means are also Allowed to obtain the desired pre-deformation. 12.2.1.1.2 The temperature of the heated area, measured by approved methods should not be exceeding 650 ° C for steels permitted use by this standard.

113

12.2.1.2 Cut by thermal means The edges cut by thermal means shall meet the requirements of paragraph 5.15.4 of AWS D1.1: 2002, with the exception of the free edges that are subject to static tensile stress, which shall be free of depressions deeper than 5 mm and slots. Depressions greater than 5 mm and notches shall be removed by grinding or repaired by welding. The reentrant corners, except the clippings beam table for connections and openings access for welding must comply with the requirements of paragraph 5.16 AWS D1.1: 2002. If other requirement is specified, it must be contained in the contract documents. Clippings beam table for connections and access openings for welding must meet the geometric requirements given in 6.1.14. Moreover, when these cut-outs or openings are executed profiles of Groups 4 and 5 of ASTM A6/A6M or profiles

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welded with a thickness exceeding 50 mm materials should be given a pre-heating temperature at least 66 ° C before cutting. 12.2.1.3 Planing edges No need to flatten or finishing the edges of plates or profiles cut with a saw, scissors or torch, unless otherwise indicated on drawings or preparing specifications edges. The use of scissors to cut edges should be avoided in places subject to the formation of plastic hinges; if used, these edges should be smooth finish, obtained by grinding, gouge or planer. The burrs should be removed to allow adjustment of parts to be bolted or welded or when they represent risk during construction or after its completion. 12.2.1.4 Bolted Construction 12.2.1.4.1 When the thickness of the material is less than or equal to the maximum diameter of plus 3 mm, screw holes can be punched. For larger thicknesses, the holes should be drilled to its final diameter and can also be subpuncionados or subdrilled with smaller diameter and subsequently machined to final diameter. The matrix for all subpuncionados holes or drill for all sub-drilled holes shall be at least 3.5 mm less than the final diameter of the hole. In places subject to the formation of bearings plastic, the holes should be tensioned areas subpuncionados and machined to the diameter end or drilled with the final diameter. When applicable, this requirement should be included in the drawings of the structure. The use of a torch for drilling holes is not allowed. 12.2.1.4.2 During bolting, pins or screws should be placed provisional to maintaining the relative position of the structural parts prior to their final fixation. Espinas can only be used to ensure the positioning of the component parts during the sets assembly is not allowed to use, by deformation force of the coincidence holes, extend them, or distort the material. Insufficient coincidence holes should be of rejection of parts. The assembly and inspection of connections with high strength bolts must be made in accordance with 6.7. 12.2.1.5 welded construction The technique to be used in welding, execution, appearance and quality of welds, and as the methods used in the correction of defects shall be in accordance with AWS D 1.1. 12.2.1.6 Finish surfaces which transmit compressive forces by contact The connections which transmit compressive forces by contact should have their surfaces

Contact prepared to provide perfect nesting, using machining, saw cutting or other suitable means. 12.2.1.7 Dimensional tolerances The dimensional tolerances shall meet the requirements specified in P.6.4 (Annex P). 12.2.1.8 Finish bases of pillars and base plates The bases of the columns and the base plates must be finished according to the following requirements:

Page 115 NBR 8800 - Based Text Revision a) base plates rolled, of a thickness not exceeding 50 mm, can be used without machining, provided it is obtained satisfactory support for contact; laminated base plates with a thickness exceeding 50 mm but less than 100 mm can be desempenadas by pressure, or planed on all contact surfaces, in order to gain support satisfactory by contact, except as indicated in paragraphs b) and c) below; plates Laminated above 100 mm base thickness as well as pillars and other base types of base plates shall be planed on all contact surfaces except as indicated in b) and c) below; b) the lower face of the base plates, which are grouted to ensure full contact with the concrete foundation, does not require planing; c) the upper face of the base plates need not planing if welds are used full penetration between these plates and the pillar. 12.2.2 Paints Factory 12.2.2.1 General requirements The factory paint and surface preparation shall conform to the requirements of Annex P. Parts of steel parts that transmit efforts by adhering to the concrete can not be painted; except in this case and in cases where the painting is unnecessary (see 10.3) in all structure should be applied in the factory, at least one layer of "primer". 12.2.2.2 inaccessible surfaces Except for contact surfaces, surfaces that will become inaccessible after fabrication should be cleaned and painted in accordance with the painting specifications of the project, prior to such fact occur. 12.2.2.3 contact surfaces There are no limitations as to the painting of surfaces in the case of connections with screws working by contact. Other contact surfaces, including cases of friction bolted connections and surfaces which transmit compressive forces by contact, except in special cases as mentioned in 6.3.4.1.1, shall be cleaned as Annex P, without being painted, the contact is occur during manufacturing; if contact is occur only in assembling such surfaces should be cleaned according to the specifications of the project and, if they are machined, should receive a corrosion-inhibiting layer of a type which can be easily removed before assembly, or of a type that need not be removed, noting, however,

115

provisions in 12.2.2.4. 12.2.2.4 surfaces adjacent to field welds Unless otherwise specified, the surfaces to be welded in the field, in a range of 50 mm on each side of the weld must be free of materials that prevent welding suitable or producing toxic gases during the welding operation. After welding such surfaces should receive the same cleaning and protection provided for the entire structure.

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12.3 Mounting 12.3.1 Alignment of bases of pillars The bases of pillars should be leveled and positioned at the correct elevation, being in full contact with the support surface. 12.3.2 Care at Mount 12.3.2.1 The structure shall be mounted flush, level and plumb within the tolerances specified in Annex Q. All parts of the structure received in the work shall be stored and handled in a manner which is not subject to excessive stresses or suffer damage. Temporary bracing, where required, in accordance with Annex E should be used, to absorb all forces to which the structure may be subjected during construction, including the resulting wind and equipment. The bracing must remain mounted, without being damaged, as long as is necessary for the safety of the structure. Whenever there accumulation of material, equipment or other natures forces on the structure during the assembly, measures must be taken to ensure that requests are absorbed corresponding. 12.3.2.2 In assembly, the structure must be bolted or welded securely, so that can absorb any permanent action, wind and shares mounting. 12.3.3 Alignment Welded or bolted permanent connections should only be completed after the party the structure, which will become rigid after the execution of such connections are properly aligned, leveled and plumbed. However, security during assembly should be guaranteed to all time. 12.3.4 Adjustment of compressed connections pillars Openings no greater can be accepted 1.5 mm in transmitting amendments pillars efforts compression by contact, regardless of the amendment used (bolted or welded with partial penetration). If the gap is greater than 1.5 mm but less than 6 mm, and if verified that there is not enough contact area, the gap will be filled with steel shims parallel faces. These shims may be made of carbon steel even if the steel is of the structure other. 12.3.5 Final Painting Responsibility for touch-up paint (including paint prior to cleaning) during and after assembling, and the final painting of the structure as a whole, must be specified in the contract. The final painting must meet the requirements of Annex P.

12.4 Quality Control 12.4.1 General The manufacturer shall establish methods of quality control within the rigor that judge necessary to ensure that all work is performed in accordance with this standard. In addition to the procedures of quality control of the manufacturer, the material and the quality of

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service shall be permanently subject to inspection by qualified inspectors representatives of the buyer. If such inspection is requested by representatives of the purchaser, stable should be stated in the bidding documents structure. 12.4.2 Cooperation All inspection by representatives of the purchaser as far as possible should be made factory or place where work is being performed. The manufacturer shall cooperate with the Inspector, allowing access to all locations where the service is running. The inspector the buyer must establish its inspection schedule so that they are the minimum interruptions of the manufacturer. 12.4.3 Rejection The material or service that does not meet the requirements of this standard may be rejected at any time during the execution of the service. The manufacturer shall receive copies of all inspection reports provided to the purchaser for the supervision, 12.4.4 Inspection of welds The inspection of the welds must be done in accordance with the requirements of the AWS D1.1. The inspection look that is required should be specified in the bidding documents and project. When nondestructive testing is required, the process, the extent, and technical standards are acceptance should be clearly defined in the bidding documents and project. 12.4.5 Identification of Steel The manufacturer must be able to demonstrate by written procedure and practice a method of application and material identification, visible at least during the operations of union Component elements of a set to be transported in full. By the method of identification should be possible to verify the correct application of the material as: a) designation of the specification; b) number of the race of steel, if required; c) Reports of tests needed to meet special requirements.

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NBR 8800 - Based Text Revision Annex A (normative) Structural steel and metal bonding materials

A.1 General A.1.1 The recommendations in this Annex apply to structural steel and metal materials link normally used in steel structures and composite steel-concrete. A.1.2 The replacement of any material taken during the manufacturing or assembly should compulsorily have the approval of the responsible for the project. A.2 Structural Steels A.2.1 The structural steel to be used in the structure must be new, the buyer must specify the acceptable level of corrosion to the steel surface, A, B, C or D: A - Surface entirely covered with scales lamination adhered to the surface, showing little or no signs of corrosion; B - Surfaces that present early corrosion and loss of scales lamination; C - Areas which have lost all scale lamination or have scales easily removable, also showing few visible pores varioliform the eye naked; D - Surfaces that have lost all rolling scale, presenting a number varioliform considerable pores with the naked eye. For more detailed specifications for appearance and surface finish, consult SSPC-Vis1 or standard SIS 05 59 00. A.2.2 Tests of impact and resistance to brittle fracture must be requested when service conditions of the structure require. A.2.3 Mechanical Properties Are given in table A.1 the flow resistances (f y) And rupture (f Structural specified by Brazilian standards and Table A.2 for some structural steels frequent use specified by ASTM.

u) For steels

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Table A.1 - ABNT steels for structural purposes NBR 7007 NBR 6648 Carbon and micro-alloyed steels Thick carbon steel plates structural and general use for structural use fy fu fy fu Class / grade Class / grade (MPa) (MPa) (MPa) (MPa) MR-250 250 400 CG-24 235 380 AR-290 290 415 CG-26 255 410 AR-345 345 450 AR-PINK 345 485 345-A or B NBR 5000

1)

NBR 6649/6650 NBR Thin sheets of carbon steel structural use (cold / hot) fy fu Class / grade (MPa) (MPa) CF-24 240 370 CF-26 260 4002) 4103)

NBR 5004

NBR 5008 Thick plates and thick coils of steel Thick steel plates with low Thin sheets of low-alloy steel alloy and high strength and high mechanical strength Low resistant to atmospheric corrosion, for structural use - requirements f fu fy fu Class / Range fy fu Class / grade y Class / grade (MPa) (MPa) (MPa) (MPa) degree thickness (MPa) (MPa) t ≤ 19 345 480 G-30 300 415 F-32/Q-32 310 410 1, 2 and 2A 19 λ

b) for V

Rkt

p lp

p

= [C + η (1 - C )] V v v lp

Where: Vp is the shear force corresponding to yielding of the soul shear, defined in l 5.4.3.2.2; Cv is the coefficient of shear force, given in G.1.2; 1

η=

115 1 +

the 2 h

G.1.2 The shear coefficient C a) for

λ ≤ h t/ ≤λ p w r C= v

b) for

h t/ >λ w r C= v

Where:

110 k E f v y h t w

151 k E v (h t ) 2 f w y

v

is determined as follows (see G.1.3)

E is the modulus of elasticity of steel; f y is the yield strength of steel;

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kv is the buckling coefficient of the Soul by shear force, given by: 5 k = 5 + () v theh 2 should be taken equal to 5.0 s

the h / exceed 3.0 or

[ 260 / h ( t / )] 2. w

G.1.3 The parameters λ, λ pAnd λr, And aeh dimensions are defined in 5.4.3.2.1. G.2 Requirements and limitations for use of the field tensile G.2.1 The relationshiph the / can not exceed 3.0 nor the relationship h t/ . w

[ 260 / h ( t / )] 2Regardless of w

G.2.2 The transverse stiffeners, as well as meet the requirements given in 5.4.3.2.3, points a), b), c) and e), must also have a minimum cross-sectional area (in a plane parallel to tables listing), given by: The = α st r

015 D

s

( ) VSd th 1 - C 18 t 2 w v V w Rd

Where: VSd is the shear force requester calculating the cross section of the beam is located where the stiffener; VRd is resistant to shear force calculation, not including the effect of field strength, according to 5.4.3.1; α is the relationship between the flow resistances of steels of soul and stiffener; r Ds is a coefficient equal to 1.0 for stiffeners placed in pairs, 1.8 for stiffeners consisting of a bracket and to the stiffeners consist of 2.4 one plate; For the meanings of other terms see 5.4.3.2.1 and G.1. G.2.3 The effect of the drift field does not apply to end panels of the soul, the panels openings nor the latter adjacent panels. G.2.4 The effect of the drift field does not apply to different requests of the normal bending simple, and should be verified interaction between the shear force and bending moment, as 5.4.3.2.4. G.2.5 The effect of the drift field also does not apply to beams with souls subject to forces concentrated without stiffeners into sections, for example, in the case of beams subjected to forces

furniture. / ANNEX H

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NBR 8800 - Based Text Revision Annex H (normative) Length buckling by bending and twisting of compressed bars

H.1 buckling bending H.1.1 The slenderness ratio of compressed element is defined as the ratio between buckling length and the radius of gyration as applicable. The length of buckling KL equal to the actual length L of the bar not braced multiplied by a factor K, called buckling coefficient can be interpreted as being equal to the length a compressed bar with labeled edges, the cross-section and whose resistance buckling are equal to the actual bar. The buckling coefficient K of a bar compressed depends on your boundary conditions and, theoretically, can vary from 0.5 to infinity. H.1.2 In Table H.1 theoretical values ​ of K are given for six ideal cases, in which the rotation and translation of the ends are totally free or totally prevented. If not we can ensure the completeness of the collet, the recommended values ​ should be used submitted. H.1.3 k values ​ for the bars belonging to the trusses can be obtained H.2 table, or can be determined from an analysis of elastic buckling of the truss considered. H.1.4 values ​ for K pillars of continuous structures are presented in Annex J. Table H.1 - Buckling Coefficient K for insulated bars (A)

(B)

(C)

(D)

(E)

(F)

Theoretical values ​ of K

0.5

0.7

1.0

1.0

2.0

2.0

Recommended Values

0.65

0.80

1.2

1.0

2.1

2.0

Dashed line indicates the line elastic buckling

Hindered rotation and translation Code to condition support

Free rotation, translation prevented Hindered rotation, free translation Rotation and translation free

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Table H.2 - Buckling Coefficient K for truss bars Case

the iç el r

Element considered

K

1

Rope

1.0

2

Extreme diagonal

1.0

3

Amount or diagonal

1.0

4

Diagonal compressed linked the center to a diagonal pulled the same section

0.5

The T an lp on m ge amba l F

5

the çi el r

6

Rope with all nodes contained outside the plane of truss

Continuous strings where A and B are only contained out of plane F1(> F2)

1.0

F ,75 0 + 025 2 F 1

The T lan p ra fo m ge

7

amba lF 8

9

Amount or diagonal

1.0

Strut continuous, connected to the center1 0,- 075 pulled one diagonal same section

Continuous amount of lattice K F (> F ) 1 2

F

t ≥ 0 5, F c

F ,75 0 + 025 2 F 1

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H.2 torsional buckling The torsional buckling length is equal to the actual length of the bar, L, multiplied for buckling coefficient, K, depending on the boundary conditions, related to the rotation and warping, whose theoretical values ​ are equal to: a) 1.00, where the two bar ends having hindered rotation, and free warping; b) 0.50, where both ends of the rotation and warping bar having prevented; c) 0.70 where one of the ends of the bar have hindered rotation and warping free and the other rotation and warping prevented; d) 2.00 where one end of the bar has free rotation and warping and another rotation and warping prevented.

/ ANNEX J

Page 151 NBR 8800 - Based Text Revision Annex J (normative) Length of bending buckling of pillars of continuous structures J.1 The length of flexural buckling of pillars of continuous structures, braced and is not braced, given by the product KL, where K is a coefficient and L is the buckling length of the pillar measured wheelbase beams. J.2 K values ​ can be obtained from the figures abacus and J.1 J.2, respectively, for braced and not braced structures, in which the indices A and B refer to the nodes the two ends of the length L of the pillar analyzed, where G is defined as: Σ Ip L p G= I Σ v L v where Σ indicates the sum of the relations length and moment of inertia (I / L) of all bar rigidly connected to the node, located in the plan that is being considered buckling the pillar, I p is the moment of inertia and L p the length of an abutment between A and B, I v is the time of inertia and L the span of a beam rigidly connected to the node. I and R are calculated in relation to v p v perpendicular to the buckling being considered plane axes. Having determined G and B Gfor a segment of the pillar, the value of K can be found The drawing a straight line between the appropriate points of the scales L Theand G B. The length of flexural buckling is sought KL, where L is defined in J.1. To end supported in the pillar base, but not rigidly connected to such bases, G is theoretically equal to ∞, but, unless you run a real kneecap, can be taken equal to 10 in practical cases. If the end of the pillar are rigidly connected to a base sized appropriately, G can be taken equal to 1.0. Values ​ may be used below 1.0 if justified by analysis. The equations which are based on an abacus are listed below: - Braced structures G G π 2 G +G TheB + The B 1 4 K 2

- Not braced structures π 2 π - 36 G G The B K = K π (6 G +G ) The B tg K

π K +2 π tg K

tg

π 2K = 1 π K

151

Page 152 152

NBR 8800 - Based Text Revision

J.3 Alternatively to the use of the abacus and J.1 J.2 figure, the K values ​ can be obtained the following approximate expressions: - Braced structures K=

064 + 1 (4G + G ) + 3 G G The B The B 128 + (2G + G ) + 3 G G The B The B

- Not braced structures K=

7 5,+ (4 G

+ G ) +1 6 G G The B The B 7 5,+ G + G The B

J.4 The procedure described in this annex is based on the following assumptions: a) all the pillars are continuous; b) elastic behavior; c) each bar structure has constant cross section; d) all the links are rigid; e) all pillars flambam simultaneously; f) does not occur in normal force significant compression in the rafters.

Page 153

NBR 8800 - Based Text Revision

153

Figure J.1 - Values ​ of K for braced structures

Figure J.2 - Values ​ of K for structures not braced

/ ANNEX K

Page 154 154

NBR 8800 - Based Text Revision Annex K (normative)

Normal force of elastic buckling Sections double symmetry with K1 and symmetrical about a point The normal force of elastic buckling, N , A double bar with cross section and symmetrical or symmetrical about a point is given by: a) to buckling bending relative to the central axis x of inertia of the cross section: N

ex

=

π 2E I

x (K L ) 2 x x

b) to buckling bending relative to the central axis of inertia y cross section:

N

ey

=

π 2E I

y (K L )2 y y

c) for torsional buckling in relation to the longitudinal axis z: N

ez

=

1 π 2EC w + GI T r 2 (K L ) 2 the z z

Where: KxLx is the length of buckling by bending with respect to the x axis; I x is the moment of inertia of the cross section with respect to the x axis; KyLy is the length of buckling due to bending in relation to the y axis; I y is the moment of inertia of the cross section relative to the y axis; KzLz is the length of torsional buckling; E is the modulus of elasticity of steel; Cw is the constant warping of the cross section; G is the modulus of transverse elasticity of steel; I T is the moment of inertia of uniform twist; r is the polar radius of gyration of the gross section relative to the shear center, the given by: r = the

r 2( + r 2 + x 2 + y 2) x y the the

Page 155 NBR 8800 - Based Text Revision xtheey the are the coordinates of the center of shear. in the direction of the principal axes x and y, respectively, relative to the centroid of the section.

155

Sections K.2 monossimétricas The normal force of elastic buckling, N , A bar with monossimétrica cross section, and whose y-axis is the axis of symmetry, is given by: a) to elastic buckling by bending relative to the central axis of inertia of the section x Cross: N

ex

=

π 2E I

x (K L ) 2 x x

b) for elastic buckling for flexion-torsion:

N

eyz

=

+N ey ez 12 1 -[ y ( r / ) 2 ] the the N

4N

1-

N 1 -[ y ( r / ) 2 ] ey ez the the (N + N ) 2 ey ez

where N ey and Nez are the normal forces of elastic buckling as K.1-b) and K1-c) respectively. If the x axis is the axis of symmetry, just replace x by y in a) and y by x and y

by x the b). the

K.3 asymmetric Sections The normal force of elastic buckling, N , A bar with asymmetric cross section (without and no axis of symmetry) is given by the smaller of the cubic root of the following equation: (

)( ( ) x 2 y 2 )( ) the - N 2 ( N - N ) the = 0 N - N N - N N - N - N2 N - N and ex and ey and ez and and ey r and and ex r the the

Where: Nex, Ney, N ezX the Y the er the are defined as K1.

/ ANNEX L

Page 156 156

NBR 8800 - Based Text Revision Annex G (normative) Openings souls of beams

L.1 This Annex applies to the design of steel beams and composite beams with section

cross I or H, biapoiadas, continuous or semicontinuous with one or more openings in the soul. In addition: - The cross section must be at least symmetrical relative to the axis passing through the median plane of the soul; - Cross-loading shall lie exclusively in the median plane of the soul, not assuming the role of normal force. L.2 When sizing for verification of ultimate limit states considering the influence openings in the souls of the beams, including the placement of reinforcements when necessary should be used specialized literature or foreign specification or standard, except for the situations provided in L.3. L.3 openings can be made ​ without reinforcement in beams whose souls have compared

h t / of the w maximum 376 E f / and whose relationship has compressed table b (/ t2 ) the maximum y fc fc 038 E f / When the openings are located within the neutral zone, defined in L.4 and y Further to the provisions L.5 and L.6, whichever is applicable, the following requirements are met: a) the yield strength of the steel must be less than or equal to 350 MPa; b) the profile must have total height less than or equal to 1000 mm; c) the profile should possess relationship between total height and width of largest table d ( b / ) equal to or f greater than 1.20; d) the pair bending moment-shear force corresponding to the center of the opening section should be less than or equal to this couple in the same position, a beam biapoiada same vain, subject to a maximum load evenly distributed as possible; e) monossimétricos profiles must satisfy simultaneously the following relations: 100 ≤ The The ≤ 1f f 2

200

048 ≤ The The ≤ 131 f2 w 070 ≤ The The ≤ 261 1f w The + The - h t > The f2 w thew 1f f) composite beams must satisfy simultaneously the following relations: t + h ≤ 160 mm c F

Page 157 NBR 8800 - Based Text Revision b

f

≤ 3000 mm

Where: b is the total width of the compressed table; fc t is the thickness of the compressed table;

157

fc The is the largest area among the areas of the upper and lower tables; f1 The f2 is the smallest area among areas of the upper and lower tables; The the soul; w is the area of ​ h is the height of the soul; t wis the thickness of the soul; hthe is the height of the openings; t c is the thickness of the slab (in the case of slabs shaped embedded steel strip is concrete above the ridge of the pan); h is the rib height of the embedded steel formwork; F bf is the effective width of the concrete slab. L.4 is defined as neutral zone region of the soul that originates in the center of the span and extends toward the support of the beam (Figure L.1), in which an opening with certain characteristics does not significantly affect the resistance to shear force and bending moment for certain boundary conditions. The neutral zone should be considered always centered compared to half the height of the profile. Abaci of figures L.2 l.10 to delimit the neutral zone for beams with circular and rectangular openings a = 2 h (Figure L.1). The relationship between the the request calculation (S d) And calculating the resistance (R d) To query the abacus must be greater of the following values ​ in the region of positive or negative moment: M M

Sd

Rd

V V

Sd

Rd

Where: M Sdis the bending moment calculation requestor; M is resistant bending moment calculation, determined in accordance with 5.4 and Annex Q, Rd whichever is applicable; VSdis the shear force calculation requestor;

Page 158 158

NBR 8800 - Based Text Revision VRd is resistant to shear force calculation, determined in accordance with 5.4.3 or Annex Q, whichever is applicable;

L.5 In the case of beams with more than one opening, the minimum spacing between edges adjacent openings, s, must meet the following criteria (Figure L.1): - For rectangular openings:

h the s ≥

the the V

V Sd

pl - V Sd 1.10

- Circular apertures: 1 5, D s ≥

D

the V

the V

Sd

pl - V Sd 110

Where: D is the diameter of the openings; the theis the length of the openings; the Vp is the shear force corresponding to the shear yielding of the soul, l determined according to 5.4.3.2.2. L.6 rectangular openings shall have rounded edges with a minimum radius of 16 mm 2 or t w, Whichever is greater. L.7 To check the serviceability limit states should be taken into account properly The influence of the openings.

Page 159 NBR 8800 - Based Text Revision

159

hthe x the

the the L neutral zone

d

d / d 2/3 S

kL

kL

L/2

L/2

Figure L.1 - Neutral zone

Page 160 160

NBR 8800 - Based Text Revision 00:50 00:45 00:40 12:35 12:30 k 00:25 10 00:20 12:15 0, 0,90 80 12:10 12:05 12:00

S R

d d

0.70

≤d/3 A circular openingthe ≤d/3 square opening h the ≤d/3 rectangular opening (2:1)the /to2 = h the

10 11 12 13 14 15 16 17 18 19 L20/ d 21 22 23 24 25 26 27 28 29 30 ≤ d / 3 in profiles Figure L.2 - Neutral zone in non-composite beams with openings for Height laminates 00:50 00:45 00:40

S R

h / t ≤ 3.76 w

Ef

y

≤d/3 A circular openingthe ≤d/3 square opening h the

d

d 12:35 12:30 0, k 00:25 90 0.95 0,80 00:20 12:15 0,70 12:10 0,60 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45 00:40 12:35 12:30 k 00:25 00:20 12:15

S R

d d

rectangular opening (2:1) ≤d/3 the /2=h the the

0,85 0.80 0.70

0.60 12:10 0.50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d

Figure L.3 - Neutral zone in composite beams with openings for Height laminates h / t ≤ 3.76 E f w y

≤ d / 3 in profiles

Page 161 NBR 8800 - Based Text Revision 00:50 00:45 00:40 12:35 12:30 k 00:25 00:20 12:15

0,90 0,80 0, 12:10 70

S R

161 ≤d/2 A circular openingthe

d d

10 0

12:05 0.60 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d

00:50 00:45 00:40 12:35 12:30 k 00:25 00:20 12:15

S R

0,80 0,70

0,90

≤d/2 square opening h the

d d

10 0

12:10 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45 00:40 12:35 12:30 k 00:25 00:20 12:15

rectangular opening (2:1) ≤d/2 the /2=h the the S

0,50

0,70

0,60

0,80

R

100

0,90

d d

12:10 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure L.4 - Neutral zone in non-composite beams for openings with height d / 2 ≤ laminates h / t ≤ 3.76 E f w y

in profiles

Page 162 162

NBR 8800 - Based Text Revision 00:50 00:45 00:40

S R

≤d/2 A circular openingthe

d

0, 85

12:35 d 12:30 0,80 k 00:25 00:20 0.70 12:15 12:10 0.60 0.50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45

S

d

square opening h

≤d/2

00:40 12:35 12:30 k 00:25 00:20 12:15

Rd

the

0,75 0,70 0.60 0.50

12:10 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45 00:40

0.75 0.70 12:35 0.60 12:30 0.50 k 00:25 S 00:20 d R 12:15 d 12:10 rectangular opening (2:1)the h≤ d / 2 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure L.5 - Neutral zone in composite beams for openings with height d / 2 ≤ laminates h / t ≤ 3.76 E f w y

in profiles

Page 163 NBR 8800 - Based Text Revision 00:50 00:45 00:40

S

d

163

≤d/3 A circular openingthe ≤d/3 square opening h the rectangular opening (2:1)the h≤ d / 3

R 12:35 d 1 12:30 00 k 00:25 0,90 00:20 0,80 0,7 12:15 0,60 0 12:10 0,50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure L.6 - Neutral zone in non-composite beams for openings with height d / 3 ≤ soldiers with h / t ≤ 3.76 E f w y 00:50

in profiles

A circular openingthe ≤d/2 00:45 ≤d/2 square opening h the 00:40 12:35 12:30 S d k 00:25 R 1 d 00 00:20 0,90 0,80 0,70 12:15 0,60 12:10 0,50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45 00:40

S R

d

d 12:35 12:30 0,95 0,90 k 00:25 0,80 00:20 0,70 0,60 12:15 0,50 12:10 h≤ d / 2 12:05 rectangular opening (2:1)the 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure L.7 - Neutral zone in non-composite beams for openings with height d / 2 ≤ soldiers with h / t ≤ 3.76 E f w y

in profiles

Page 164 164

NBR 8800 - Based Text Revision 00:50 00:45 00:40 12:35 12:30 k 00:25 00:20 12:15

S R

≤d/3 A circular openingthe ≤d/3 square opening h the

d d

0.95 0.90 0.80

12:10 0.70 12:05 0.65 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure L.8 - Neutral zone for openings in composite beams with high d / 3 ≤ in profiles soldiers with 00:50 00:45

S

d

h / t ≤ 2.44 w

Ef

y

≤d/3 A circular openingthe

00:40 Rd square opening h the ≤d/3 12:35 0.90 12:30 0.80 k 00:25 00:20 0.70 12:15 0.60 12:10 0.50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 S 00:45 rectangular opening (2:1) d ≤d/3 R the /2=h 00:40 the the d 12:35 0,90 12:30 0,80 k 00:25 0,70 00:20 12:15 0,60 12:10 0,50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure L.9 - Neutral zone for openings in composite beams with high d / 3 ≤ in profiles soldiers with h / t ≤ 3.76 E f w y

Page 165 NBR 8800 - Based Text Revision 00:50 00:45 00:40 12:35 12:30 k 00:25 00:20 12:15

S R

165

≤d/2 A circular openingthe

d d

0.85 0.80 0.70 0.60

12:10 0.50 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45 00:40 12:35 12:30 k 00:25

≤d/2 square opening h the 0.80 0.70

00:20 12:15

0.60 0.50

12:10 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d 00:50 00:45 rectangular opening (2:1)the h≤ d / 2 00:40 0.75 0.70 12:35 0.60 12:30 0.50 k 00:25 00:20 S d 12:15 R d 12:10 12:05 12:00 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 L/d Figure l.10 - Neutral zone in composite beams for openings with height d / 2 ≤ in profiles soldiers with h / t ≤ 3.76 E f w y / ANNEX M

Page 166 166

NBR 8800 - Based Text Revision Annex M (normative) Fatigue

Applicability M.1 M.1.1 This Annex applies to structural steel elements and metallic bonds subject to actions with large numbers of cycles, ranging from tensions in the elastic regime whose frequency and magnitude are sufficient to initiate cracks and progressive collapse (fatigue). M.1.2 The requirements given in the M.2 M.6 may not apply in part or in whole the Welded connections involving one or more tubular profiles. It is recommended to check these leads to fatigue, making the necessary changes to keep the level of acceptability predicted by this standard, the use of AWS D1.1 and the following Publication: - Zhao, X.-L.; Herion, S.; Packer, JA; Puthli, RS; Sedlacek, G.; Wardenier, J.; Weynand, K.; van Wingerde AM & Yeomans, NF (2000). Design guide for circular and rectangular hollow section welded joints under fatigue loading. International Committee pour le Developpement et l'Etude de la Construction tubulaire (CIDECT). TÜV Verlay Rheinland. Germany. M.2 General M.2.1 The requirements of this Annex apply to calculated stresses based on charges not weighted whose maximum value is equal to 066 f , Where yf is the yield strength of the steel. y

M.2.2 The range of voltages is defined as the magnitude of the voltage change due the application or removal of variables unweighted actions. In the case of the signal inversion voltage at any point, the variation range of voltages should be determined by the difference Algebraic the maximum and minimum voltage values ​ considered at this point. M.2.3 In the case of butt joint welding with full penetration groove, the permissible limit for the range of variation of stresses (σ SR) Applies only to welds with internal quality meeting the requirements of sections 6.12.2 and 6.13.2 of AWS D1.1: 2002. M.2.4 No check for fatigue resistance is required if the variation range of voltages is less than the threshold σTHgiven in Table M.1. M.2.5 No checking fatigue resistance is required if the number of cycles application of the load is less than 20,000. M.2.6 The resistance to cyclic loads determined by the requirements of this Annex shall apply only structures: - With adequate corrosion protection or subject only slightly corrosive atmospheres such as normal atmospheric conditions; - Subject to temperatures below 150 ° C.

Page 167 NBR 8800 - Based Text Revision M.3 Calculation of maximum voltage and the maximum variation range of voltages M.3.1 The calculation of stresses should be based on elastic analysis. Tensions should not be amplified by stress concentration factors due to geometrical discontinuities. M.3.2 For screws and threaded round bars subjected to tension, the calculated stresses should include the leverage effect, if any. M.3.3 In case of combined axial force with bending moment, the maximum stresses, of each type, should be determined by appropriate combinations of actions applied. M.3.4 For beams with symmetric cross sections, bolts and welds should be symmetrically about the axis of the bar or strains used in the calculation of range of voltages must include the effects of eccentricity. M.3.5 For angles subject to normal force, where the center of gravity of the connecting welds lies between the lines passing through the center of gravity of the cross section of the bracket and connected by the center tab, the effects of eccentricity can be ignored. If the center of severity of welds lies outside this zone, the total stresses, including those due to eccentricity should be included in the calculation of range of voltages. M.4 permissible variation range of voltages The range of voltages must not exceed the values ​ given below: a) for categories of detail A, B, B ', C, D, E and E', the permissible range of variation of stresses, σ In megapascals, is determined by: SR

167

σ

SR

= 327 C f N

0333≥ σ

TH

Where: FSRis the allowable range of variation of stresses in megapascals; Cf is the constant given in Table M.1 for the corresponding category; N is the number of cycles of variation of tension during the useful life of the structure; σ is the permissible limit of range of voltages, for an infinite number of TH cycles request, given in Table M.1, in megapascals. b) to detail the category of F, the allowable variation range of stresses, σ given by:

σ

SR

=

× 10 4 C 11 f N

0167 ≥σ

SR, Must be

TH

c) for elements of traction plate attached by welds at the end of slot full penetration welds slot partial penetration fillet welds or combinations

Page 168 168

NBR 8800 - Based Text Revision

Earlier, disposed transversely to the direction of the stresses, the allowable range for stresses in the cross section of the plate pulled at the transition line between the base metal and the Soldering must be determined as follows: - Based on early cracking from the transition line between the base metal and the weld detail category for C, by the following equation:

σ

SR

=

0333 14 4 × 10 11 ≥ 68 9 MPa N

- Based on initiation of cracks from the root of the weld in the case of welding slot partial penetration or fillet welds without reinforcing or contouring to detail category C ', by the following equation:

σ

SR

= 172 R

14 4 × 10 11 PJP N

0333

Where: RPJPis the reduction factor for welds notch partial penetration, with or without = 1 0,Use category detail C) given by: fillet reinforcement (if R PJP 065 - 059 R

PJP

=

2 the t

+ 072

p 0 t 167 p

w t

p

≤ 1 0,

2a is the length of the face unwelded root in the direction of plate thickness pulled in mm; w is the size of the leg of the fillet or contour enhancement, if any, toward the tensioned plate thickness, in millimeters; t p is the thickness of the sheet pulled in millimeter. - Based on initiation of cracks from the roots of a pair of solder fillets cross on opposite sides of the plate pulled to category C'' detail by the following equation:

σ

SR

= 172 R

14 4 × 10 11 FIL N

0333

Where: RFILis the reduction factor for joints up only a couple of fillet weld = 1 0,. Cross. Use category detail is C R FIL

Page 169 NBR 8800 - Based Text Revision

006 + 072 R

FIL

=

t 0167 p

169

w t p ≤ 1 0,

M.5 screws and threaded round bars The range of voltages must not exceed the permissible range calculated as follows: a) bolted subject to the court on the screws, the permissible range of variation stress in the material of the element bound is given by the following equation, where C given in section 2 of Table M.1: σ

SR

=

327 C N

f

0333 ≥σ

F are f andTH

TH

b) for high strength bolts, common bolts and threaded round bars with laminated, cut or machined thread, the range of variation of tensile stresses in the net area the bolt or threaded round bar, from normal force and bending moment including leverage, must not exceed the allowable range given by the following equation: σ

SR

=

327 C N

f

0333 ≥σ

TH

The C factorshould be taken equal to 3.9 x10 8 (For category E '). The limit σ f is taken equal to 48 MPa (as for D). The effective area shall be determined as 6.3.2.2.

should TH

For joints in which the material within the handle is not limited to steel or joints which not are pre-tensioned according to the requirements of Table 16, the normal force and the moment including leverage (if any) should be regarded as passed exclusively by threaded screws or round bars. For joints in which the material within the handle is limited to steel, pretensioned according to the requirements of the table 16 allows an analysis of the relative rigidity of the parts connected and bolts to determine the range of variation of tensile stresses in pretensionados screws due to the normal force and the bending moment including effect lever. Alternatively, the variation range of tension in the bolt can be considered equal to 20% of net area stress due to axial force and bending moment from all actions, permanent and variable. M.6 special requirements of fabrication and assembly M.6.1 is allowed to plates of longitudinal expected to be left in place and, if used, must be continuous. If amendments are required to the plates of waiting in long joints, such amendments shall be made with solder slot full penetration and excess solder should be abraded prior to positioning along the bar in the joint.

Page 170 170

NBR 8800 - Based Text Revision

M.6.2 In transverse joints subject to tensile, plates, wait, if used, should be removed and you need root extraction and counter the weld joint. M.6.3 In T joints or corner, made ​ with solder slot full penetration, a trickle of reinforcement not less than 6 mm should be added in the reentrant corners. M.6.4 The surface roughness of the torch cut edges, subject to variations of tracks significant stresses shall not exceed 25 microns using as the reference standard ASME B46.1. M.6.5 reentrant corners in areas of cuts, cut-outs and openings for access Welding must not form a radius smaller than 10 mm. To this must be done a sub-hole or broqueado subpuncionado with smaller radius, machined subsequently to the end beam. Alternatively, the radius can be obtained by flame cutting, in which case, to grind the cut surface to the state of shiny metal. M.6.6 For transverse joints soldered slot full penetration in regions of tension high traction extenders should be used to ensure that the end of the weld occurs out of the finished board. The extenders should be removed and the end of the weld should be facemills polished up with the edge of the connected parts. Limiters at the ends of the gasket not should be used. M.6.7 See section 6.2.6.2.6 for requirements on returns on certain fillet welds subject to cyclic loadings.

Page 171 NBR 8800 - Based Text Revision

171

Table M.1 - Parameters of fatigue Description

Category voltage

Constant C f

Σ limit Potential point of beginning TH (MPa) cleft

Section 1 - base material away from any welding 1.1 Base metal except steel resistant to corrosion Atmospheric not painted with Laminated surfaces subject or not the cleaning surface. The 250x108 165 Cut edges torched with surface roughness not greater than 25 microns but not reentrant corners. 1.2 Metal sturdy steel base atmospheric corrosion not painted with surfaces laminated, or not subject to surface cleaning. Edges B 120x108 110 cut with a torch surface roughness does not greater than 25 microns but not reentrant corners. 1.3 Parts with holes drilled or widened. Parts with reentrant corners clippings or other B 120x108 110 geometrical discontinuities meeting the requirements of M.6, except for openings Access welding. 1.4 Sections transverse laminated with openings for access of welding meeting the requirements of 6.1.14 and M.6. Pieces with holes C 44x108 69 drilled or extended containing screws connecting light bracings, with short application. Section 2 - Materials connected bolted Gross Section 2.1 of the base metal

Away from any welding or structural bond.

Away from any welding or structural bond.

In any outer edge or perimeter of opening.

In reentrant corners openings for access welding or any hole small (may contain screws for connections unimportant).

joints overlap with high strength bolts satisfying all requirements apply friction connections. 2.2 Base metal at net section together with screws in high Resistance calculated based in contact resistance, however, with manufacturing and installation serving all requirements for connections by friction. 2.3 Base metal at net section other bolted except lugs and plates connected by pin.

Through the gross section next to the hole.

B

120x108

110

B

120x108

110

In net section with origin on the edge of the hole.

D

22x108

48

In net section with origin on the edge of the hole.

Page 172 172

NBR 8800 - Based Text Revision Table M.1 - Fatigue Parameters (continued) Description

Category voltage

Constant C f

Σ limit TH (MPa)

2.4 Base metal at net section eyelets and plates connected by pin.

E

11x108

31

Starting point potential crack In net section with origin at the edge of hole.

Section 3 - Connections welded components of bars composed of sheets or profiles 3.1 Base metal and weld metal bars without fittings, From the surface Composite sheets or profiles or discontinuities connected by longitudinal welds B 120x108 110 internal weld in continuous slot of spaced points full penetration, with extraction end of the weld. root and counter-welding or continuous fillet welds. 3.2 Base metal and weld metal bars without fittings, From the surface Composite sheets or profiles or discontinuities connected by longitudinal welds internal weld, B' 61x108 83 continuous slot of including solder full penetration, with plates the connection plate expected not removed, or hold. continuous fillet welds. 3.3 Base metal and weld metal welding the ends Longitudinal openings access for welding rods composed. 3.4 Metal base at the ends of segments longitudinal of welds Intermittent fillet. 3.5 Metal base at the ends of lamellae welded of length partial, narrower than the table having ends esquadrejadas or reduction gradually in width, with or without welds transverse at the

D

22x108

48

From the end Weld, penetrating the soul or desk.

E

11x108

31

In the bound material in local start and end deposition welding.

On the table at the foot of transverse weld end, the table by the end of

wider or ends, than more the lamellae table with welds the transverse ends.

also longitudinal the edgeweld, of theortable with wider lamella.

Table 20 ≤ Thickness mm

E

11x108

31

Table thickness> 20 mm 3.6 Metal base at the ends of lamellae welded of length partial wider than the table without transverse welds in ends.

E'

8 3.9 x10

18

E'

8 3.9 x10

18

At the edge of the table by the end of the weld the lamella.

Page 173 NBR 8800 - Based Text Revision

173

Table M.1 - Fatigue Parameters (continued) Description

Category voltage

Constant C f

Σ limit TH (MPa)

Section 4 - Connects end with longitudinal fillet welds 4.1 Base metal at junction of bars requested axially with end connections welded longitudinally. The welds should be on each side the bar axis, so that balance the stresses in the weld. t ≤ 13 mm

E

11x108

Starting point potential crack

Starting from any end welding, extending the base metal. 31

8 E' 3.9 x10 18 Section 5 - Connects welded transverse to the direction of stress 5.1 Base metal and weld metal in amendmentsof profiles rolled or welded section From similar cross-sectional made discontinuities penetration groove welds B 120x108 110 the internal metal Overall, these welds must welding or along the be flush with the metal face melting. base by middle of grinding toward the applied voltages. 5.2 Base metal and weld metal in seams with solder cutout full penetration, Transitions having a width From or thick with slope discontinuities between 8 and 20%; welds must the internal metal be flush with the base metal welding or along the by grinding in face melting or direction of the applied voltages. beginning of the transition when f ≥ 620MPa. y f < 620MPa B 120x108 110 y t> 13 mm

B' f ≥ 620MPa y 5.3 Metal base with f ≥ 620MPa and weld metal y in seams with solder cutout full penetration, going transition width taken with radius equal to or greater

61x108

83

From discontinuities

600 mm,towith the point tangent the edge of the weld penetration; welds should be flush with the metal base by grinding toward the applied voltages.

B

120x108

110

the internal metalthe welding or along face melting.

Page 174 174

NBR 8800 - Based Text Revision Table M.1 - Fatigue Parameters (continued) Description

Category voltage

5.4 Base metal and weld metal in seams, joints or T corner joints with welds cutout full penetration, transition thickness having C with inclination between 8 and 20% without transition or thickness, when the excess solder does not is removed. 5.5 Base metal and weld metal in crosslinked top or T or corner, in ends of element traction plate made with penetration groove welds partial, supplemented with fillet weld reinforcement or contour; F SRshould be as small of the following two values: Home cleft from the C transition between the weld metal and basis. Early crack at the root of solder. 5.6 Base metal and weld metal crosslinks in the ends of element traction plate made with two solder fillets on sides opposite the plate; FSRmust be the smaller of two values following:

C'

Home cleft from the transition between the weld metal andC basis. Early crack at the root of solder. 5.7 Metal Based on elements traction plate and base metal souls in beams or tables in

C''

C

Constant C f

44x108

44x108

Σ limit TH (MPa)

69

69

Starting point potential crack From discontinuities the superficial transition between the weld and the base metal extending the metal base, or along the face melting.

From discontinuities the geometric transition between the weld and the base metal extending the metal base, or from the root weld subjected to tensile extending through the weld.

0333 σSR= 172RPJP144×1011 Not anticipated. N

44x108

69

From discontinuities the geometric transition between the weld and the base metal extending the metal base, or from the root weld subjected to tensile extending through the weld.

0333 σSR= 172RFIL144×1011 N Not anticipated. 44x108

69

From discontinuities geometries in the foot

transverse foot fillet weld stiffeners adjacent soldiers.

extending fillet weld the metal basis.

Page 175 NBR 8800 - Based Text Revision

175

Table M.1 - Fatigue Parameters (continued) Description

Category voltage

Constant C f

Σ limit TH (MPa)

Section 6 - Metal based on crosslinked welded bars 6.1 Base metal in connection an accessory made with solder longitudinal slot full penetration, subject to longitudinal request when detail of the transition accessory is made with a radius R and polished weld in Terminations for agreement: R ≥ 600mm

B

120x108

110

600 mm > R ≥ 150mm

C

44x108

69

150 mm > R ≥ 50mm

D

22x108

48

50 mm > R 6.2 Base metal in connection an enhancement of coplanar same thickness made from longitudinal weld groove subject to full penetration cross-demand, or without longitudinal request detail when the transition the fitting is done with a radius R and polished weld the terminal points for agreement:

E

11x108

31

B

120x108

110

C

44x108

69

D

22x108

48

E

11x108

31

C

120x108

110

Starting point potential crack

Near the point of tangency on end of accessory.

When excess solder is removed: R ≥ 600mm 600 mm > R ≥ 150mm 150 mm > R ≥ 50mm 50 mm > R When excess solder not is removed: R ≥ 600mm

Near the point of tangency on end of accessory, or the welding, face melting, the main element or accessory.

600 mm > R ≥ 150mm

C

44x108

69

150 mm > R ≥ 50mm

D

22x108

48

50 mm > R

E

11x108

31

In the transition the and welding the between base metal can be at the edge the main part or in accessory.

Page 176 176

NBR 8800 - Based Text Revision Table M.1 - Fatigue Parameters (continued) Description

Category voltage

Constant C f

Σ limit TH (MPa)

Starting point potential crack

6.3 Base metal in connection an enhancement of coplanar made with different thickness longitudinal weld groove subject to full penetration cross-demand, or without longitudinal request detail when the transition the fitting is done with a radius R and polished weld the terminal points for agreement: When excess solder is removed: R> 50 mm

R ≤ 50 mm

D

22x108

48

E

11x108

31

When excess solder not is removed: Any ray 6.4 Base metal subject to tensions along the longitudinal links transverse bars, or withouttensions transverse, connected by longitudinal welds fillet or groove partial penetration when detail of transition accessory is made with a radius R and polished weld in Terminations for agreement:

E

R> 50 mm

D

22x108

48

R ≤ 50 mm

E

11x108

31

11x108

31

In the transition between the and welding the base metal in edge of the material thinner. From the end the weld. In the transition between the and welding the base metal in edge of the material thinner.

At the end of welding or from transition between the weld and the base metal extending the metal base or accessory.

Page 177 NBR 8800 - Based Text Revision

177

Table M.1 - Fatigue Parameters (continued) Description

Category voltage

Constant C f

Σ limit TH (MPa)

Section 7 - Base metal fittings along the short 7.1 Base metal subject to longitudinal request, along with accessories connected by welds longitudinal slot of full penetration when detail of transition accessory is made with a radius R less than 50 mm, length of the accessory longitudinal direction equal aae normal to the surface height same bar ab: the < 50 mm

Starting point potential crack

In the base metal near the end of the weld.

C

44x108

69

50 mm ≤ 12b or 100mm

D

22x108

48

a> 12 b or 100mm when b ≤ 25 mm

E

11x108

31

a> 12 b or 100mm when b> 25mm 7.2 Base metal subject to tensions along the longitudinal accessories with or without tensions cross-linked by welds longitudinal fillet or Slot partial penetration, detail when the transition the fitting is done with a radius R and polished weld the terminal points for agreement:

E'

8 3.9 x10

18

R> 50 mm

D

22x108

48

R ≤ 50 mm

E

11x108 Section 8 - Miscellaneous

31

8.1 Base metal at the type shear connectors connected by pin with head fillet weld or electro-fusion.

C

44x108

69

In the transition between the and welding the base metal.

Throat of the weld.

8.2 Shear on throat fillets transverse welds or longitudinal continuous or intermittent. 8.3 Base metal at the welds

At the end of extending the welding base metal.

150x1010 F

0167 × 4 σ = 11 10 Cf ≥σ SR TH N

55

E

11x108

31

At the end of

buffer holes or tears.

weld in the base metal.

Page 178 178

NBR 8800 - Based Text Revision Table M.1 - Fatigue Parameters (continued) Description

Category voltage

Constant C f

Σ limit TH (MPa)

150x1010 8.4 Shear in welds buffer holes or tears.

F

8.5 High-strength bolts Total installed without prestressing, Common bolts and bars round threaded with thread laminated, cut or machined. E' Range of variation of stress Traction calculated based in net area, including effect lever when applicable.

0167 × 4 σ = 11 10 Cf ≥σ SR TH N

55

8 3.9 x10

48

Starting point potential crack In the flat transition between the solder and the metal basis.

At the root of the thread extending the net section.

Page 179 NBR 8800 - Based Text Revision Table M.1 - Parameters of fatigue - Details (continued) Section 1 - base material away from any welding 1.1 and 1.2

1.3

1.4

Section 2 - Materials connected bolted 2.1 Vista sheet removed overlapping

2.2 Vista sheet removed overlapping

2.3

2.4

Section 3 - Connections welded components of bars composed of sheets or profiles 3.1 or

*

* Weld penetration groove

or

179

Page 180 180

NBR 8800 - Based Text Revision Table M.1 - Parameters of fatigue - Details (continued)

Section 3 - soldered connections of the components of bars composed of sheets or profiles (continued) 3.2

* * Weld slot full penetration 3.3

3.4

50-150

3.5

3.6 No soldering Typical Section 4 - Connects end with longitudinal fillet welds 4.1 t = thickness

t = thickness

Section 5 - Connects welded transverse to the direction of stress 5.1

5.2

Weld full penetration groove - grinding

Weld full penetration groove - grinding

fy≥ 620 MPa Cat B

Weld full penetration groove - grinding

Page 181 NBR 8800 - Based Text Revision

181

Table M.1 - Parameters of fatigue - Details (continued) Section 5 - Connects welded transverse to the direction of tension (continued) 5.3 R ≥ 600 mm Weld Notch full penetration - Grinding

5.4

fy≥ 620 MPa Cat B Potential start site cracking due to stresses traction in flexion

Weld Notch full penetration

5.5 Start Location potential cracking due Weld Notch Weld Notch the voltage partial penetration partial penetration traction in flexion

5.6 Fissure potential due to traction deriving bending

5.7

Section 6 - Metal based on crosslinked welded bars 6.1

Page 182

Weld Notch penetration total

Weld Notch penetration total

182

NBR 8800 - Based Text Revision Table M.1 - Parameters of fatigue - Details (continued) Section 6 - Metal based on crosslinked welded bars (continued)

6.2 G = grinding up facemills *

*

* Weld slot full penetration 6.3 *

G = grinding up facemills

*

* Weld slot full penetration 6.4 or

*

*

* Weld Notch partial penetration Section 7 - Base metal fittings along the short 7.1

(Average)

Page 183 NBR 8800 - Based Text Revision

183

Table M.1 - Parameters of fatigue - Details (conclusion) Section 7 - Metal base with a short accessories (continued) 7.2 or *

* Weld Notch partial penetration Section 8 - Miscellaneous 8.1

8.2

8.3

8.4

8.5 Locations fissure

Locations fissure

Locations fissure

/ ANNEX N

Page 184 184

NBR 8800 - Based Text Revision Annex C (normative) Specific requirements for bars of varying section

N.1 Applicability N.1.1 This Annex applies to the bars of variable section that meet the following requirements: - The cross sections should be I, H or coffin, with two axes of symmetry; - Tables must have constant section between sections contained against instability; - The height (s) soul (s) should vary linearly between sections contained against instability. N.1.2 The calculation and design of bars of variable section that meets the requirements listed in N.1.1 must be made in accordance with the requirements contained in section 5 of this document, except in The following cases, in which some adaptations are required. N.2 Normal Force sturdy traction calculation The normal force resistant traction calculation shall be determined in accordance with the requirements of subsection 5.2, taking the gross cross-sectional area of ​ lower height and net area of ​ the section subject to breakage. N.3 Normal force resistant compression calculation The normal force resistant compression calculation shall be determined in accordance with the requirements of subsection 5.3, taking the dimensions and geometric properties of the section lower height. Furthermore, the determination of elastic buckling stresses, the coefficients of buckling by bending around the axis perpendicular to the spirit and torque must be determined by rational analysis or using specialized bibliography (the coefficient of buckling by bending around the axis perpendicular to the tables can be determined as for prismatic bars). N.4 resistant bending moment calculation for non-slender beams and slender N.4.1 The resistant bending moment calculation for the limit state of lateral buckling with twist between sections contained laterally, can not be less than the bending moment requestor calculation of the section where most compressive stress occurs at the tables. For this limit state apply the requirements of subsection 5.4, but determining the modification factor for bending moment diagram is not uniform C b, Or rationale for using bibliography specialized or, optionally, by taking this coefficient equal to 1.0. N.4.2 In determining the parameters of slenderness λ, λ be adopted geometric properties of greater height section.

λ any limit state are p andrFor

/ ANNEX P

Page 185 NBR 8800 - Based Text Revision Annex P (normative) Best practices for implementing structures P.1 General Provisions

185

P.1.1 Scope In this Annex best practices for running steel structures are established buildings. These practices should be extended to joint structures whenever possible. In addition that, in the absence of other instructions in the contract documents, business practices here contained will serve as a rule for the manufacture and assembly of the structure. P.1.2 Settings P.1.2.1 Engineer / Architect Designated by the owner as his representative authority with overall responsibility for project and the integrity of the structure. P.1.2.2 contract document Documents that define the responsibilities of the parties involved in the bidding, purchasing, fabrication and erection of the structure. Such documents usually consist of a contract, drawings and specifications. P.1.2.3 Drawings P.1.2.3.1 Design drawings Design drawings executed by the party responsible for structure design P.1.2.3.2 Drawings manufacturing and assembly Manufacturing drawings and assembly field, and the responsibility of the manufacturer or fitter for execution of work. P.1.2.3.3 Detalhador Entity that produces manufacturing drawings and assembly. P.1.2.4 Assembler The structure responsible for assembling the part. P.1.2.5 Manufacturer The responsible for the manufacture of steel structure part. P.1.2.6 General Contractor A contractor hired by the owner with full responsibility for building structure.

Page 186 186

NBR 8800 - Based Text Revision

P.1.2.7 Laminated Materials Rolled Steel acquired specifically to meet the requirements of a particular project.

P.1.2.8 release for construction Release owner, allowing manufacturing to be initiated under the conditions contract, including the ordering of raw materials and the preparation of fabrication drawings. P.1.2.9 SSPC "Steel Structures Painting Council," responsible for the publication of "Steel Structures Painting Manual ", volume 2 (" Systems and Specifications "). P.1.3 Design criteria for buildings and similar structures The clauses of this standard governing the design of steel and composite structures for buildings, unless there are other requirements in the contract documents. P.1.4 Responsibility Project P.1.4.1 When the owner to provide design, drawings and specifications, the manufacturer and the assembler are not responsible for the correctness, suitability or legality of the project. P.1.4.2 The manufacturer is not responsible for practicality or safety of assembly If this structure is performed by a third party. P.1.4.3 If the owner wishes that the manufacturer or assembler run the project, drawings and specifications or assume any responsibility for the correctness, suitability, or legality of the project, should clearly state your requirements in the contractual documents. P.1.5 patented devices Except where the contractual documents require the project to be provided by the manufacturer or assembler, manufacturer and assembler assume that all patent rights necessary have been acquired by the owner, and that the manufacturer or assembler will fully protected and free to use designs, patented devices or parts required by contractual documents. P.1.6 Security Mount P.1.6.1 The assembler must be responsible for the security and methods of assembly structure. P.1.6.2 The engineer shall be responsible for the adequacy of the structure in the project, not responsible, however, for the functions described in P.1.6.1.

Page 187 NBR 8800 - Based Text Revision P.2 Classification of materials P.2.1 Structural Steel The term "Structural Steel", when used in defining the scope of work in the documents contract only consists of the following items: - Anchor bolts for steel structure;

187

- Basis of structural steel; - Laminated beams; - Base plates for steel structure; - Connections; - Bracings; - Pillars; - Crane rails, bumpers, batten seams, bolts and nuts; - Frames of doors or gates that are part of the steel structure; - Expansion joints connected to the steel; - Means of connection of the steel structure: screws

of factory for links

screws

Used

screws

of field

for fix

permanent s

parts for thetransport and of structure

for links

permanent s

- Floor plates (chess or smooth) connected to the steel; - Welded structural steel beams - Tapamentos sleepers; - Grids of structural steel beams; - Structural steel hangers, when connected to the steel; - Leveling plates; - Stated or listed spars in the project; - Foundations for machines made of laminated and / or plates profiles, related to the structure and indicated the drawings of the structure; - Structural steel canopies;

Page 188 188

NBR 8800 - Based Text Revision - Monorail beams, structural profiles, when attached to the structure; - Permanent pins; - Tuesdays; - Spacers, angles, tees, cleats and other fasteners essential to steel structure; - Shear connectors;

- Steel cables that are a permanent part of the steel structure; - Struts; - Supports made of steel profiles, pipes, conveyors and similar structures; - Supports false ceilings made of steel profiles with a height equal to or greater section of the 75 mm; - Rods and hangers, main or auxiliary, forming part of the steel structure; - Trusses. Other items p.2.2 steel or metal The classification "structural steel" does not include items of steel, iron or other metal not specifically listed under P.2.1, even if such items have been indicated on the drawings as part of the structure or connected to it. These items include, but are not limited to: - Bars and wire forms; - Various metals; - Metal ornaments; - Chimneys, storage tanks and pressure vessels; - Required for the assembly of materials provided by third parties other than items manufacturers or assemblers of steel structure; - Hoods; - Handrails. P.3 Drawings and Specifications P.3.1 Steel structures P.3.1.1 To ensure that proposals are appropriate and complete documents contract should include drawings of the steel structure project clearly showing

Page 189 NBR 8800 - Based Text Revision work to be performed, indicating dimensions, sections, steel types and positions of all parts, levels of floors, center lines and removal of pillars, contraflechas and them consisting sufficient size to accurately report the amount and type of steel parts

189