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PRELIMINARY COPY-REV-1
BASIC CONCEPTS OF PRE-ENGINEERED STEEL BUILDINGS
By: S. Khalid Hashmi Deputy General Manager –Technical Services
Kirby Building Systems India Ltd PEB-KBSIL-Rev-1
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Table of Contents 1. INTRODUCTION................................................................................................. 3 2. NOMENCLATURE.............................................................................................. 4 3. CONCEPT OF PRE-ENGINEERED METAL BUILDING SYSTEM......... 29 4. ADVANTAGES OF PRE-ENGINEERED BUILDING SYSTEMS.............. 37 5. APPLICATIONS OF PRE-ENGINEERED STEEL BUILDINGS ............... 39 6. PEB SYSTEMS IN INDIA................................................................................. 46 7. WORKING WITH PEB SYSTEMS ................................................................. 47 8. DESIGN OF PEB SYSTEMS ............................................................................ 48 9. MATERIALS AND FABRICATION ............................................................... 53 10. SITE ERECTION ............................................................................................... 54 11. WARRANTY....................................................................................................... 54 12. CONCLUSION ................................................................................................... 54 13. REFERENCE BOOKS & CODES: .................................................................. 55
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Chapter – 1 PRE-ENGINEERED STEEL BUILDINGS SYSTEMS
INTRODUCTION Technological improvement over the years has contributed immensely to enhancement of quality of life through various new products & services. Another major impact of this phenomenon was the availability of these products & services in ready-to-use forms. One such revolution was the Pre-Engineered Steel Buildings (PEB). Though its origin can be traced back to 1960’s, its potential has been felt only during the recent years. This was mainly due to the development in technology, which helped in computerize the design & drawing. Though initially only off-the shelf products were available in these configurations, aided by the technological development, tailor made solutions are also made using this technology in a very short duration. A recent survey by the Metal Building Manufacturers Association (MBMA) shows that about 60% of the non-residential low rise building in USA are Pre-Engineered steel buildings. The pre-engineered steel building industry is in its infancy in the Indian sub-continent. However, with the setting up of the state-of-the-art Kirby Building Systems Manufacturing plant near Hyderabad and the significant advantages of this form of construction over conventional structural steel and RCC construction, it is inevitable that PEB system of construction would soon dominate the Indian construction market. Unfortunately, design schools and the textbooks tend to ignore this type of construction, apparently assuming that it belongs to manufacturer’s domain. The principal objective of this is to present architects, engineers, contractors, construction specifiers, facility managers and building officials with enough information to enable them to make intelligent decisions in their design and evaluation activities. Pre-engineered Buildings offer complete freedom of design to accommodate the customer needs.
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Chapter – 2 NOMENCLATURE ACCESSORY: A supplementary building component added to a basic Kirby Structure, such as a door, window, skylight, ventilator, etc. AISI: American Iron & Steel Institute AISC: American Institute of Steel Construction ALUMINIZED: Aluminium coated steel ANCHOR BOLTS: Bolts used to anchor the structural members to the concrete floor, foundation or other support. This usually refers to the bolts at the bottom of all columns. ANCHOR BOLT DRAWING: A plan view of the foundation showing all dimensions and sections required to properly locate the anchor bolts, including projection above concrete, required recess, etc. Column reactions (magnitude and direction), and base plate dimensions are also included. ANGLE: A hot rolled member with two legs making an angle of 900 in between. APPROVAL DRAWING: A general arrangement drawing with details sent to the customer to verify design and dimensions and to verify the sales contract description of materials and services the manufacturer has agreed to furnish. This includes the anchor bolt drawings, framing plans, elevations and sections. ASSEMBLY: Arrangement of different components to fit together. ASTRAGAL: A closure between the two leaves of a double swing or a double slide door used to close the joint. AUTOMATIC WELDING: A welding procedure utilizing a machine to make a weld. AUXILIARY LOADS: All specified dynamic live loads required by the contract document other than the basic design loads which the building must safely withstand such as cranes, material handling systems and impact loads. A.W.S: American Welding Society. AXIAL FORCE: A force tending to elongate and shorten a member. BACK-UP PLATES: The plates used in between the hillside washer and column web. BASE ANGLE: Continuous angle fixed to floor slab or grade beam for attachment of all wall panels.
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BASE CHANNEL: A light gauge cold-formed channel, which replaces the base angle when liner panel or double sheeted partitions are required. BASE PLATE: The end-plate of a column or beam, which rests on the supporting surface, usually secured with anchors. BAY: The space between frame centerlines or primary supporting members in the longitudinal direction of the building. Also called stanchion spacing. BEAD MASTIC: Sealant furnished in a continuous roll, normally used for sealing roof panel laps. See Endlap Mastic. BEAM: A horizontal Structural Member, usually carrying vertical load, which is ordinarily subject to bending. BEAM, CANTILEVER: A beam supported at one end only and free at the other, such as brackets, canopies, flagpoles. BEAM, CONTINUOUS: A beam, which has more than two points of support, (continuous span). BEAM, SIMPLE: A beam simply supported at both ends, theoretically with no rotational end restraint. BEARING FRAME: Frame made up of beams and columns so constructed that joints are not capable of transferring moment due to lateral loads, usually used at sheeted end walls of a metal building, and when not subject to auxiliary loads or to further building expansion. BENT PLATE: A plate bend to form an angle. BILL OF MATERIAL: A list of components used for fabrication, shipping, receiving and accounting purposes. BIRD SCREEN: Wire mesh used to prevent birds from entering the building through ventilators and louvers. BLIND RIVET: A small headed pin with expandable shank for joining light gage metal. Typically used to attach flashing, gutter, etc. also referred to as a Pop Rivet. BRACE GRIP: Galvanized steel strands when formed helical hairpin that wraps itself tightly on the strand with a little help. BRACE RODS/ANGLES: Rods or angles placed diagonally in roof and walls for transferring wind loads to foundations and stabilizing the building. BRACED BAY: The bay where the bracing is provided.
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BRACING STRAP: The steel band (strap) used to strengthen the purlins and girts. BRACKET: A structural support projecting from a wall or column to which another structural member is fastened. Example: Crane runway brackets. BRIDGE CRANE: A load lifting system consisting of a hoist, which moves longitudinally on, a runway made of beams and rails. Loads can be moved to any point within a rectangle formed by the bridge span and runway length. BRIDGING: Structural members used to give weak axis stability to open web joists. BRITISH THERMAL UNIT (BTU): That amount of heat required to raise the temperature of one pound (2.2 Kg) of water by 1oF (0.56oC) BUILDING CODES: Regulations established by recognized agencies describing design loads, procedures and construction details for structures. Usually apply to designated geographical areas. BUILDING LENGTH: The length of the building in the longitudinal direction. BUILDING WIDTH: It is the lateral width of the building. BUILT-UP SECTION: A structural member, usually an “H” shape, made from individual flat plates welded together. BUILT-UP ROOFING: A roof covering made up of alternating layers of tar and asphaltic materials (mostly used for flat roofs). BUTT PLATE: The end plate of a structural member, which usually butts against a similar plate of another member to form a connection. Used for moment resisting connections. BUTTERFLY CANOPY: A free standing, single column supporting roof structure, having a valley gutter at the centerline of the building, and the two outer edges of the roof projecting upwards. BY FRAMED GIRT: The girt, which passes continuously from the outside flanges of the columns. “C” SECTION: A member formed from steel coils into the shape of a block “C”. CABLE CATCH ASSEMBLY: It is the operating handle used to open and close the Ridge Ventilator. CALORIE: Quantity of heat required to raise the temperature of one gram of water through 10C (1 BTU = 252 Calories).
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CAMBER: Upward curvature of a beam in the place of its web before loading, to offset an anticipated deflection when load is applied. CANOPY: An overhanging or projecting roof structure with the extreme end usually unsupported. CAP PLATE: A plate located at the top of a column or end of a beam for capping the exposed end of the member. Used for pinned conditions. CAPILLARY ACTION: The property of water by which it passes through the small passages above the water level. CATWALK: A narrow walkway used to provide access to mechanical equipments normally supported on roof platforms. CAULK: See sealant. CAULKING: Sealant used in making watertight joints. CENTER LINE: It is the line passing through center of gravity of the section. CHANNEL (HOT ROLLED): A member formed while in a semi-molten state at the steel mill to a general “C” shape having standard dimensions and properties specified by AISC or the steel producer. CHECKERED PLATE: The hot rolled plate (strong in bending), used for flooring in catwalks, staircases, etc. CLEAR HEIGHT: The vertical dimension from the finished floor to the top of the cap plate of the column. CLEAR SPAN: Building without internal columns. CLIP: A plate or angle used to fasten two or more members together. CLOSER: Mechanical device, usually attached to a door, which prevents closing with excessive force. CLOSURE (FOAM CLOSURE): Profiled foam material used inside or outside profiled roof or wall panels to form weather tight seal. COIL: The roll of sheets or wires.
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COLD-FORMED STEEL: The process of using press brakes or rolling mills to cold form sheet or strip steel into desired shapes. A steel member that has been formed into its functional shape without heat being applied to aid in the forming. COLLATERAL LOAD: The static load other than basic design loads, such as sprinklers, mechanical and electrical systems and ceilings. COLUMN: A primary structural member used in a vertical position on a building to transfer loads from main roof beams, trusses or rafters to the foundation. COMPONENT: An independent part of an assembly. COMPRESSION: The act of causing material to contract or shorten. CONCENTRATED LOAD: A load applied on a member at a point or over a very short distance. CONCRETE NOTCH: A notch or block-out formed along the outside edge of the foundation to provide support for the wall panels and to help serve as a closure along their bottom edge. CONTINUITY: The terminology given to a structural system denoting the transfer of loads and stresses from member to member as if there were no connections. CONTINUOUS BEAM: A beam, which has more than two points of support. CONTINUOUS RIDGE VENT: Two or more accessories mounted on the building ridge that allows air circulation. CONTRACT DOCUMENTS: The documents, which define the responsibilities of the parties involved in the sale, design, supply and erection (if any) of a metal building system. Such documents normally consist of a contract and specification. Plans may be included. CORNER COLUMN: A column at any corner of a building. Corner columns may be primary frame columns or post and beam columns. COUNTER FLASH: The trim used to connect the sidewall sheeting of the main building with the roof sheeting of the small building. COVERING: The exterior metal roof and wall paneling of a metal building system. CRANE: A machine designed to lift and/or move material by means of a hoist.
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CRANE BACK-LEG: The free vertical member of the Crane Tower. CRANE BEAM: Support for overhead traveling bridge crane. CRANE BRACKET: Structural support welded to the primary building frame to permit attachment of a crane runway beam. (see bracket). CRANE BRIDGE SPAN: It is the span of the beam over which the crane trolley moves. CRANE CAPACITY: It is the capacity of the crane, which it can lift safely. CRANE LEG: The vertical member of the Crane Tower, on which the crane beam rests. CRANE LOAD: The weight of crane trolley. CRANE RAILS: Rails welded or bolted to crane beams to form the track for bridge crane wheels. CRANE STOPPER: A small vertical member welded to the top of the crane beam to stop the crane bridge. CROSS SECTION: An engineering term referring to a drawing or a plan section of any object cut at right angles to its axes. CURB: Raised flashing around roof openings to form waterproof openings. CURVED EAVE: Curved panels provided at eave. DAMPER: Baffle plate in a ventilator. DEAD LOAD: Weight of the structure. DEFLECTION: The displacement of a structural member of system under load. DESIGN LOADS: The loads expressly specified in the contract documents, which the metal building system is designed to safely resist. DIAGONAL BRACING: See Brace Rods.
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DIAPHRAGM ACTION: The capacity of roof, wall or floor system to resist load in its own plane (as building roof and wall systems resisting longitudinal wind load without rod bracing). DOOR GUIDE: An angle or channel guide used to stabilize or keep plumb a sliding or rolling door during its operation. DOOR STOPPER: A Clip bolted to door vertical stile, to stop it from sliding. DOUBLE CHANNEL: Two channels placed web to web for additional strength. Normally used in end post conditions. DOUBLE FACE TAPE: The tape, which is capable to stick from both the sides, used with insulation. DOUBLE SLIDE DOOR: The sliding door with two door leaves. DOWNSPOUT: A hollow section used to carry water from the gutter of a building to the ground or storm drain. DOWNSPOUT ELBOW/SHOE: Cold formed sheet metal matching the downspout shape and curved at bottom so as to direct water away from a wall when attached to the lower end of a downspout. DOWNSPOUT STRAPS: The metal straps used to fix the downspouts with the sidewalls. DRIFT PIN: A tapered pin used during erection to align holes I steel members to be connected by bolting (also called spud wrench). EAVE: A line along the roof/sidewall intersection formed by the inside faces of the roof and wall panels. EAVE FLASHING/TRIM: A sheet metal closure which functions primarily to provide weather tightness in a structure and secondarily to enhance appearance. EAVE GUTTER: The gutter at eave used to drain water. EAVE HEIGHT: The vertical dimension from finished floor to the eave. EAVE STRUT: Structural member at the eave, which supports roof, cover and connects to wall panels. EAVE STRUT CLIP: The clip used to support the eave strut. EDGE DISTANCE: The distance between the plate corner and the center of the bolt.
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ELASTIC DESIGN: A design concept utilizing the proportional behavior of materials when all stresses are limited to specified allowable values of the yield stress of the materials. ELEVATION: - Distance above or below a prescribed datum or reference. b) Engineering term referring to any side view of a structure. END FRAME: A frame located at the endwall of a building, which supports the loads from a portion of the end bay. END WALL: An exterior wall, which is perpendicular to the ridge of the building. END WALL COLUMN: A vertical member located at the endwall of a building, which supports the girts. END WALL EXTENSION: The projection of the roof past the endwall. END WALL RAFTER: Normally a cold formed “C” section supported by end posts on post and beam endwalls. End rafters can also be a built-up plate or hot rolled section if required by design loads. END LAP: A term used to describe the lap condition occurring at a purlin location where the end of one panel overlaps the panel below it. END LAP MASTIC: Sealant in extruded bead form used to seal roof panel endlaps for weather tightness. ENDPLATE: A plate welded at the end of a member. ERECTION: The on site assembling of pre-fabricated components to form the complete structure. ERECTION DRAWINGS: A package of drawings issued for construction and includes anchor bolt drawings and roof and wall framing (erection) plans that identify individual components and accessories furnished in sufficient detail to permit proper erection of the building. EXPANSION JOINT: A separation between adjoining parts, which is provided to allow small movements, such as those caused by temperature changes, to occur independently. EXTERIOR MOUNTED: A girt system where the girts are mounted outside the columns and are supported by the outside column flange.
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FABRICATION: The manufacturing process usually performed in a plant to convert raw material into finished metal building components. The main operations are cold forming, cutting, punching, welding, cleaning and painting. FAR SIDEWALL: The sidewall of the building, which is on the other side. FASCIA: An accessory whose function is to enhance the appearance of a wall. Also used to cover the eave or gable of a building. FIELD: The “Job site”, “building site”, or general market area outside of the manufacturer. FIELD WORK: A term used to indicate the need for field personnel to modify building components before final assembly is possible. FILLER STRIP: See “Closure”. FIN NECK BOLT: The bolts whose heads are flattened (reduced head size) and used at the exposed surface of the framed openings. FINISHED FLOOR: Top of the concrete slab or the finished concrete surface. FIXED BASE: A column base that is designed to resist rotation as well as horizontal or vertical movement. FLANGE: The projecting edge of a structural member. FLANGE BRACE: An angle member from the flange of columns or rafters to girts or purlins to provide lateral support and stability. FLASHING: A sheet metal closure primarily to provide weather tightness in a structure and to enhance appearance. FLAT MILD WASHER: Washers used in between the nuts and Hillside washer for the bracings. FLUSH FRAMES: A wall framing system where the outside flange of the girts and columns are flush. FOOTING: A pad or mat, usually of concrete, located under a column, wall, or other structural member, that is used to distribute the loads from that member into the supporting soil without exceeding the allowable soil bearing pressure.
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FORCE: The action of one body on another body, which changes or tends to change its state of rest or motion. A force may be expressed in kN/cm², N.m or other similar units and may act in any one of the following ways: a) Compression c) Tension e) Flexure
b) Shear d) Torsion
FOUNDATION: The substructure, which supports a building or other structure. FRAME: Primary structural members made up of columns, rafters which support secondary framing. FRAMED OPENING: Framing (headers and jambs) and flashing which surround an opening in a building. Usually for field installed accessories such as overhead doors. FRAMING: The primary and secondary members (columns, rafters, girts, purlins, brace rods, etc.), which go together to make up the skeleton of a structure to which the covering can be applied. GABLE: The triangular portion of the endwall of a building directly under the sloping roof and above the eave height line. GABLE ANGLE: Angle fastened to purlins at rake for attachment of endwall sheets. GABLE ROOF: A ridged roof that terminates in gables. GABLE TRIM: A flashing designed to close the opening between the roof and endwall panels. GAGE: The distance between holes (see “Holes in Plates”). GAUGE: Numerals referring to thickness of thin sheeting materials. No direct mathematical relation between gauge number and thickness; the higher the gauge number, the thinner the sheeting material. GALVANIZED: Steel coated with Zinc for corrosion resistance. GIRDER: A steel member (either hot rolled or built-up). GIRT: Secondary horizontal member to which wall panels are attached usually cold formed “Z”. GIRT CLIP: Angle clips used to connect the girts to the columns.
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GLAZING: Providing glass panels instead of wall sheetings. GRADE: The term used when referring to the ground elevation around a building. GRADE BEAM: A concrete beam around the perimeter of a building. GRATING: Flat steel bars when welded with some spacing in between to form a strong flooring system. GROUT: Non-shrinking sand cement mixture used under base plates to obtain uniform bearing surface. GUSSET PLATE: Usually a triangular steel stiffener plate used to help in distributing the load at a connection. GUTTER: A channel member installed at the eave of the roof for the purpose of carrying water from the roof to the drains or downspouts. “H” SECTION: A steel member with an H cross-section. HAIRPIN: Reinforcing steel used to transfer anchor bolt shear (due to column thrust) to concrete floor mass. HANDRAILS: Horizontal and vertical supports at staircase ends. HANGAR DOORS: These doors provide huge access space required for Aircraft Hangar Buildings and Ship repair service buildings. HAUNCH: Intersection of column and rafter. HAUNCH BRACE: A diagonal brace from the intersection of the column and rafter section of the rigid frame to the eave to prevent lateral buckling of the haunch. HEADER: Horizontal member over an opening in a wall. HEM: Edge of trim or flashing turned 180 degrees on itself for increased strength. HIGH STRENGTH BOLTS: Any bolt made from steel having a tensile strength in excess of 690 mega Pascal. Some examples are: ASTM A-325, A-354, A-449 and A-490. HIGH STRENGTH STEEL: Structural steel having a yield stress in excess of 36000 pounds per square inch (250 Mpa).
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HILLSIDE WASHER: A washer having non-parallel faces normally used on brace rods. HINGED BASE: A column base that is designed to resist horizontal and vertical movements only. HIP ROOF: A roof, which rises by inclined planes from all four sides of a building. The line where two adjacent sloping sides of a roof meet is called the Hip. HOOD: Metal flashing to cover exterior sliding door track along the full length of the door header. HOT ROLLED SHAPES: Steel section (angles, channels, S-shapes, W-shapes, etc.), which is formed by rolling mills while the steel, is in a semi-molten state. HOLES IN PLATES: The following are the terms used. PITCH: Distance between centerlines of holes along longitudinal axis of plate. GAGE: Distance between centerlines of holes along transverse axis of plate. EDGE DISTANCE: Distance from center of hole to edge of plate. HORIZONTAL KNEE SPLICE: The horizontal connection type between the column and the rafter. HOT ROLLED SHAPES: Steel sections (angles, channels, I-beams, etc.), which are formed while in a semi-molten state at the steel mill to a shape having standard dimensions and properties specified by AISC or the steel producer. IMPACT LOAD: The load, which strikes forcefully. IMPACT WRENCH: A pneumatic device used to tighten nuts on bolts. INSULATION: Any material used in building construction for the reduction of heat transfer. INTERMEDIATE RAFTER SPLICE: The connection between the two pieces of a rafter member. INTERNAL PRESSURE: Pressure inside a building, which is a function of wind velocity and number and location of openings. JACK BEAM: A primary member used to support another beam or truss and eliminate a column support.
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JAMB: Vertical member at the side of a wall opening. JIB CRANE: A cantilevered boom or horizontal beam with hoist and trolley. The lifting machine may pick up loads in all or part of a circle around the column to which it is attached. JIG: A device used to hold pieces of material in a certain position during fabrication. JOIST: Horizontal member for supporting floor or roof decking. KICK-OUT: An extension attached to the bottom of a downspout to direct water away from a wall. Also referred to as Turnout or Elbow. KILO-CALORIE (K.CAL): Quantity of heat required to raise the temperature of one kilogram of water by 1oC. KILOGRAM: Metric Unit of Mass (1 Kg – 2.2 lbm) KIP: An imperial unit to measure force equal to 1000 pounds equivalent to 4.4 kilonewtons. KIRBY-DECK PANEL: Standard corrugated panel used for floor deck. KIRBY-RIB PANEL: Standard corrugated panel used for roof, liner and soffits. KIRBY-WALL PANEL: Standard corrugated panel used for exterior surfaces of wall. KNEE: See Haunch. KNEE-BRACE: A diagonal brace designed to resist horizontal loads usually from wind or moving equipment connecting the column to a beam by forming a rigid triangle. LEAN-TO: A structure dependent upon another structure for partial support and having only one slope or pitch. LEVELLING PLATE: A steel plate used on top of a foundation or other support on which a structural column can rest. LINER PANEL: Interior wall sheeting. LINTEL: A beam: concrete, steel or stone, in masonry walls, placed above doors, openings or windows to support masonry above. LIP: A stiffener at the edge of flange of cold-formed members.
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LIVE LOAD: Any variable temporary load on the structure. LOADS: a) Dead Load b) Impact Load c) Roof Live Load d) Seismic Load
e) Wind Load f) Crane Load g) Collateral Load h) Auxiliary Load
LONGITUDINAL EXPANSION JOINT: A joint down the length of a building to allow small, relative movements, such as those caused by temperature change, in the building width. LOUVER: An opening provided with slanted blades, fixed or movable, to allow flow of air. MACHINE BOLTS: Mild steel bolts conforming to ASTM-A307. MAIN MEMBERS: The main load carrying members of a structural system including columns, endwall posts, rafters and other main support members. MANSARD FASCIA: A tilted fascia projected from the wall and extended above roofline to form as decorative appearance and to hide the roofline. MASONRY: Construction materials such as bricks, concrete blocks, ceramic blocks and concrete. MASTIC: Material used to seal cracks, joints and laps. MBMA: Metal Building Manufacturers Association. MBMA CODE OF STANDARD PRACTICES: A listing of normal conditions that apply to the sale, design, fabrication and erection of a metal building system. METAL BUILDING SYSTEM: A metal building system consists of a group of coordinated components, including structural members, exterior covering panels, fastening devices and accessories, which have been designed for specific loads, which will work together compatibly and which have engineered so that they may be mass produced and assembled in various combinations, or in a combination with various collateral materials, to provide an enclosed or partially enclosed structure. METER: Meter unit of length (1 m = 3.28ft)
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MEZZANINE: An intermediate floor within a metal building used for offices or storage, may or may not be connected to mainframe building, and consisting of beams, columns, joists, deck and edge angles to receive reinforced concrete. MICRON: Equivalent to 0.001 Millimeter. MIL: Equivalent to 0.001 inch. MOMENT: The tendency of a force to cause rotation of bending about a point or axis. Force times a distance (Torque). MOMENT CONNECTION: A connection designed to transfer moment as well as axial and shear forces between connecting members. MOMENT OF INERTIA: A physical property of a member which helps define strength and deflection characteristics. MONITOR: Raised gable or triangular portion of main building at ridge location to allow lighting or ventilation at vertical sides of monitor. MONOLITHIC CONSTRUCTION: A method of pouring concrete grade beam and floor slab together to form the building foundation without forming and pouring each separately. MONORAIL: A single rail support for a material handling system. Normally a standard hot rolled I-Beam. MONORAIL BEAM: A single beam support for a material handling system. Normally a hot rolled I-beam. MONO-SLOPE: Single Slope Roof. Mpa: Mega-Pascal. MULLION: A vertical bar or pier between panes or sections of windows and screens. MULTI-SPAN BUILDING: Building consisting of more than one gable across the width, which may or may not have interior columns within each gable. NEWTON: Metric unit of force (1N = 4.45 lbf) NOTCH: A corner cut in the concrete edge at finished floor level, where the wall sheeting rests.
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PASCAL: Metric unit of stress or pressure, force per unit area (N/M2) PANEL: The roof and wall sheeting. PARAPET WALL: That portion of the vertical wall, which extends above the roofline at the intersection of the wall and roof. PARTITION: A non-load bearing interior wall. It can sustain its own weight but does not support the ceiling or roof and withstands a minimal 0.25-kN/M²-wind load. PEAK: The uppermost point of a gable. PEAK PANEL: The panel, which is used at the ridge. PEAK SIGN: A sign attached to the peak of the building at endwall showing Kirby as the building manufacturer. PERSONNEL DOOR: An accessory, which provides an entrance to the building interior. PIECE MARK: A number given to each component of the building for erection identification. PIER: A concrete structure designed to transfer vertical load from the column base to a footing. PIG SPOUT: A sheet metal section designed to direct the flow of water out through the face of the gutter rather than through a downspout. PILASTER: A reinforced or enlarged portion of a masonry wall to provide support for roof loads or lateral loads on the wall. PINNED BASE: A column base that is designed to resist horizontal and vertical movement, but not rotation. PIN CONNECTION: A connection designed to transfer the axial and shear forces between connecting members, but not moments. PIPE FLASHING: An accessory used to cover pipes (such as sewer or furnace ventilation pipes) that penetrate into the roof panel. PITCH: Slope of the roof. PLASTIC DESIGN: A design concept based on multiplying the actual loads by a suitable load factor using the yield stress as the maximum stress in any member.
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PLASTIC PANELS: See Translucent Light Panels. PLAN: The vertical projection of a building horizontal cross section. PONDING: The gathering of water at low or irregular areas on a roof. POP RIVET: Used for joining flashing and light gauge metal trims. PORTAL FRAME: Column and beam bracing used in lieu of standard rod or cable bracing, to provide clear access. POST AND BEAM ENDWALL: A system of endwall framing consisting of upright or vertical members (posts) with pinned ends and supporting horizontal beams. PRE-ENGINEER: To design and detail components beforehand. Used also to mean the fabrication and design of standard sections. PRE-FABRICATE: To fabricate or build beforehand. To manufacture standard sections that can be rapidly assembled. PRE-PAINTED COIL: Coil metal, which received a paint coating prior to the forming operation. PRESS BRAKE: A machine used in cold-forming metal sheet or strip into desired cross section. PRESTRESSED CONCRETE: Concrete in which the reinforcing cables, wires or rods in the concrete are tensioned before there is load on the member, holding the concrete in compression for greater strength. PRIMARY FRAMING: The main load carrying members of a structural system, generally the columns and rafters or other main support members. PRIMER PAINT: The initial coat of paint applied in the shop to the structural framing of a building for protection against the elements during shipping and erection. PRISMATIC BEAM: A beam with uniform rectangular cross section PURLIN: A horizontal secondary structural member bolted to the rafters, which transfers the roof loads from the roof covering to the primary frames. PURLIN EXTENSION: A projecting secondary member used in connection with overhanging roofs.
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PURLIN LINE: The extreme outer, or exterior, edge of the purlins. R.F: A single gable rigid frame building. RAFTER: Primary member supported on columns. RAKE: The intersection of the plane of the roof and the plane of the gable. RAKE ANGLE: Angle fastened to purlins at rake for attachment of endwall sheets. RAKE TRIM: Sheet metal flashing used to cover the intersection of the roof and the endwall of a building. REACTIONS: The resisting forces at the column bases of a frame, holding the frame in equilibrium under a given loading condition. REINFORCING STEEL: The steel bars placed in concrete to help carry the tension, compression and shear stresses, as well as temperature stresses. REVISION: A significant change in building design, building order, or product worthy of notation. RIDGE: Peak of a gabled building. RIDGE CONNECTION: A connection between two members which transfers the moment from one side of the connection to the other side and maintains under application of load the same angle between the connected members that exist prior to the loading. Also, a connection that maintains continuity. RIDGE CAP: Continuous metal flashing used to close roofing material along the ridge of a roof. RIDGE VENT: The ventilators used at the ridge line. RIGID FRAME: A structural frame consisting of members joined together with rigid (or moment) connections so as to render the frame stable with respect to imposed loads, without the need for bracing in its plane. RISERS: The vertical rise of the steps of the staircase. ROLL-UP DOOR: Door that is supported on a shaft or drum and a vertical track. ROOF COVERING: The exterior roof skin consisting of panels or sheets, and their attachments and weather sealants.
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ROOF CURB: The flat horizontal platform used at roofs to support the power ventilators. ROOF EXTENSION: An extension of the roof beyond the endwall and/or sidewall of a building. ROOF MONITOR: The ventilation system used at the ridgeline. ROOF PITCH: Ratio of rise of total width of a single slope. ROOF SLOPE: The angle that a roof surface makes with the horizontal. Usually expressed in units of vertical rise to 10 units of horizontal run. ROOF SNOW LOAD: The load induced by the weight of snow on the roof of the structure. ROPESEAL: (See “Sealant”) SS: Single slope clear span buildings SV: Space Saver building – a single gable clear span with straight columns and flush girts to offer maximum clearances. SAG ROD, STRAP OR ANGLE: A tension member used to limit the deflection of a girt or purlin in the direction of weak axis. SANDWICH PANEL: A panel assembly used as covering; consists of an insulating core material with inner and outer skins. SCREEDING: The process of striking off the excess concrete to bring the top surface of the concrete to proper finish and elevation. SEALANT: Any material, which is used to close up cracks or joints to protect against leaks. SECTION MODULUS: A physical property of a structural member. It is used to design and basically describes the bending strength of a member. SECONDARY FRAMING: Members, which carry loads to the primary framing. In metal buildings this term includes base angles, purlins, girts, eave struts, flange braces, etc. SEISMIC LOADS: The loads developed due to the earthquakes. SELF-DRILLING SCREWS (SDS): Used for attaching panels and trims to girts and purlins. Pre-drilling is not necessary.
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SELF-TAPPING SCREWS (STS): Same function as S.D.S but needs pre-drilled holed. SHEAR: The force tending to make two contacting parts slide upon each other in opposite directions parallel to their plane of contact. SHEETING: The exterior cover for a building, generally light gage metal, which has been cold formed into a configuration having appearance, weatherproofing and structural qualities. SHEET NOTCH: A notch or block formed along the outside edge of the foundation to provide support for the wall panels and serve as a closure along their bottom edge. SHEETING ANGLE: An angle used to support sheeting. SHIPPER: A list that enumerates by part number or describes each piece of material or assembly to be shipped. Also called talley sheet or bill of materials. SHIMS: Small steel plates used for leveling base plates or packing between structural members. SHOP DETAILS: Details prepared for and used by manufacturing in the fabrication of parts and assemblies. SHOP PRIMER PAINT: The initial coat of primer paint applied in the shop. SHOULDER BOLT: A fastener used to attach wall and roof paneling to the structural frame. It consists of a large diameter shank and a small diameter stud. The shank provides support for the panel rib. SHOT PIN: A device for fastening items by the utilization of a patented device, which uses powdered charge to imbed the item in the concrete and/or steel. SI: The International symbol for the metric unit used by the United States (Le System International d’ Unites). SIDELAP: A term used to describe the lap condition occurring at the side or lengthwise direction of panels. SIDELAP FASTENER: A fastener used to connect panels together at the side lap. SIDEWALL: A term used to describe the entire composition of a building side. SIDEWALL OVERHANG: A projection of the roof past the sidewall.
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SILL: The bottom horizontal member of a door or window opening. SIMPLE SPAN: A term used in structural analysis to describe a support condition for a beam, girt, purlin, etc, which offers no resistance to rotation at the supports; opposite to continuous. SINGLE SLOPE: A slope in one plane. The slope is from one wall to the opposite wall. SINGLE SPAN: A building or structural member without intermediate support. SKYLIGHT: Translucent fiberglass panel used at roof to transmit natural light. SLATS: The flat strips used in the Roll-up door shutter. SLEEVE NUT: A long, slender nut normally used to join two brace rods of the same diameter together. (Also known as coupling). SLIDE DOOR: A single or double leaf door, which opens horizontally by means of overhead trolleys. SLOT: A long hole used for the access for the movements. SOFFIT: The underside covering of any exterior portion of a metal building. SOIL PRESSURE: The load per unit area structure will exert through its foundation on the soil. SOLDIER COLUMN: A column in sidewalls, outside the mainframe lines, located in extended bays to support sidewall girts framed at top with jack beam to adjacent two main frames. SPALL: A chip or fragment of concrete, which has chipped, weathered or otherwise broken from the main mass of concrete. SPAN: Distance between the supports of beams, girders or trusses. SPANNER: A component used to connect the endwall rafters with the columns. SPECIFICATIONS: A statement of particulars of a given job, as to size of building, quality, and performance of men and materials to be used, and the terms of the contract. The most common specification found in the metal building industry is the “Recommended Guide Specifications For Metal Building Systems” published by the Metal Building Manufacturers Association.
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SPLICE: A connection in a structural member. S.S.D.: Single Slide Door. STAINLESS STEEL: An alloy of steel, which contains a high percentage of chromium. Also may contain nickel or copper. STEEL LINE: The extreme outer limits of a buildings’ structural framing system to which the sheeting is attached. STEP IN EAVE HEIGHT: The condition where a lower building is attached to a higher building at the endwalls, resulting in one building with different eave heights at each end. STIFFENER: Plate welded to a member to prevent buckling. STIFFENER LIP: A short extension of material at an angle to the flange of cold-formed structural members, which adds strength to the member. STILES: The vertical side members of framed and paneled doors. STITCH SCREW: Used to fasten side laps of panels. STRESS: A measure of the load on a structural member in terms of force per unit area (kips per sq. in) (Mpa). STRUCTURAL STEEL MEMBERS: Load carrying members. May be hot rolled sections, cold-formed shapes, or built-up shapes. STRUTS: A brace fitted into a framework to resist force in the direction of its length. STRUT PURLIN: The purlins located at the wind column lines. STUD: A vertical wall member to which exterior or interior covering or collateral material may be attached. May be either load bearing or non-load bearing. SUCTION: A partial vacuum resulting from wind loads on a building, which causes a load in the outward direction. TAPERED MEMBER: A built-up plate member consisting of flanges welded to a variable depth web, which slopes from one end to the other.
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TEMPERATURE REINFORCING: Lightweight deformed steel rods or wire mesh placed in concrete to resist possible cracks from thermal expansion or contraction. TENSILE STRENGTH: The longitudinal pulling stress a material can bear without tearing apart. TENSION: Stress in a structural member created by forces tending to draw it apart longitudinally. THERMAL BLOCK: A spacer of low thermal conductance material. THERMAL CONDUCTIVITY (K): The rate of heat transmission by conduction in unit time through unit area of an infinite slab in a direction perpendicular to the surface for unit temperature difference, expressed as BTU per hour per square foot per inch thickness per oF. THERMAL CONDUCTANCEI: The rate of heat flow, in BTU’s per hour, through a square foot of material of specified thickness whose surfaces have a temperature differential of 1oF THERMAL RESISTANCE I: Resistance of heat flow. The reciprocal of conductance I. THERMAL TRANSMITTANCE (U): The rate of temperature in unit time through unit area of an assembly of materials for unit difference, expressed as BTU per hour per square foot per oF. This is also referred to as the overall coefficient of heat transfer. THROAT: Minimum width of ventilator air inlet. THRUST: A horizontal component of a reaction. TIE: A structural member that is loaded in tension. TOLERANCE: A fractional allowance for variations from the specified standard weight, dimensions, etc., of mechanical construction. TORQUE WRENCH: A wrench containing an adjustable mechanism for measuring and controlling the amount of torque or turning force to be exerted, often used in tightening nuts and high strength bolts. TRACK: A metal way for wheeled components; specifically one or more lines of ways, with fastenings, ties, etc., for a craneway, monorail or slide door.
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TRANSLUCENT: Allowing the passage of light, but not permitting a clear view of any object. A translucent material is semi-transparent, or semi-clear. TRANSVERSE: The direction perpendicular to the ridge. TRANSVERSE EXPANSION JOINT: A joint across the width of a building to allow small relative movements, such as those caused by thermal expansion and contraction of the materials used in the structure. TREAD: The horizontal length of the step of a staircase. TRIBUTARY AREA: The area, which contributes load to a specific structural component. TRIM: The metal sheet flashings used to close the gaps. TRUSS: Structural member made up of several individual parts welded or bolted together, the completed unit acting as a beam. TUBE COLUMN: A vertical structural support member made of a hollow square tube. Normally used as an interior support column in multi-span buildings or mezzanine floors. TURN-OF-THE-NUT METHOD: An approved method for pretensioning high strength bolts. The nut is turned from the snug-tight position, corresponding to a few blow of an impact wrench or the full effort of a man using an ordinary spud wrench, the amount of rotation required being a function of the bolt diameter and length. UH CRANE: A multi-rail, under hung, material handling system, manually or electrically operated. UHE CRANE: An electrically operated UH Crane. UL RATING: Underwriter’s Laboratories certification rating. UNIFORM LOAD: Loads that cover all or part of a beam and throughout the portion covered, the amount of load per unit of length is the same. UPLIFT: Wind load on a building, which causes a load in the upward direction. VALLEY GUTTER: A channel used to carry off water from the “V” of roofs of multi-gabled buildings.
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VAPOR BARRIER: Material used to retard the flow of vapor or moisture into walls and thus prevent condensation within them. VENTILATION: The process of supplying outside fresh air to, or removing air from an enclosure. VENTILATOR: An accessory usually used on the roof that allows air to pass through. WAINSCOT: Wall material, used in the lower portion of a wall that is different from the material in the rest of the wall. WALL BEARING: Wall capable of supporting a vertical load, other than its own weight. WALL COVERING: The exterior wall skin consisting of panels or sheets and their attachments, trim and weather sealants. WALL, NON BEARING: Wall capable of supporting its own weight only. WEB MEMBER: A secondary structural member vertical or diagonal interposed between the top and bottom chords of a truss. WEB: That portion of a structural member between the flanges. WEEP HOLES: Openings in flashings, etc., to permit drainage and reduce pressures. (Usually field-drilled holes). WHEEL BASE: The distance between the two wheels of a crane trolley. WHEEL LOAD: The load, which is transferred through the wheels of the crane trolley. WICKET DOOR: The small door in the main Roll-up or slide doors. WIND BENT: See “Portal Frame”. WIND COLUMN: A vertical member supporting a wall system designed to withstand horizontal wind loads usually at end walls. WIND LOAD: A loading representing the pressure exerted on a structure by a given wind velocity. A load caused by the wind blowing from any horizontal direction. WORK POINT: An intersection of planes from which dimensions are located.
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Chapter – 3 CONCEPT OF PRE-ENGINEERED METAL BUILDING SYSTEM A typical assembly of a simple metal building system is shown below to illustrate the synergy between the various building components as described below:
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EXTERIOR CLADDING Provides a weather tight envelope and transfers structural loads like wind and live loads to the supporting secondary framing. Provides lateral bracing to the roof purlins and wall girts.
SECONDARY FRAMING “Z” shaped roof purlins and wall girts are used for the secondary framings. They are lighter than the conventional hot-rolled “C” shaped sections. At the roofs with appreciable slope over 0.4/10, proper purlin orientation Nesting of these “Z” shaped members at the supports at the frame locations allows them to act as continuous members. This doubles the strength capacity of the “Z” shaped members at the laps and supports where the maximum internal stresses normally occur. Whenever purlins are stabilized by roofing or top flange, they are considered laterally supported only for downward loads, which produce mostly compressive stresses in the purlin’s top flange. But when wind produces upward forces, the bottom flange acts mostly I compression. There, the purlin is unbraced Purlins and girts receive the loads from the roof and wall covering and transfer to the main building frames. Purlins and girts provide lateral bracing to the building columns and rafters preventing lateral buckling of the compression flanges.
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MAIN FRAMES Frames of pre-engineered buildings are made from an extensive inventory of standard plates stocked. PEB frames are normally tapered and often have flanges and webs of variable thicknesses along the individual members. The frame geometry matches the shape of the internal stress diagram thus minimizing material waste and reducing the total weight of the structure. Moment resisting frames provide lateral stability and transfer the roof and wall loads to the foundations through anchor bolts. For full structural efficiency, member’s compression flange requires lateral bracings. Under downward loads, the top flange of the primary members is mostly in compression. Fortunately, this flange carries roof purlins, which provides the necessary bracing. Under wind uplift, however, it is the bottom flange that is mostly in compression. Hence, this bottom flange needs to be stabilized against bucking by flange bracing, consisting of usually of bolted angle sections. Similarly bracings are needed at the interior flanges of rigid-frame columns that are normally in compression under downward loads. The bracing connects the interior flange of the wall girts.
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ENDWALL FRAMING The function of endwall framing is to resist all loads supplied to the building’s endwalls and to support wall girts. In buildings with expandable endwalls, a regular interior frame is provided. In buildings where endwalls are non expandable, light end frames are provided supporting the vertical loads and contains wall girts, with or without wall cross bracings. The endwall girts may have a flush or by-pass inset.
WIND BRACING Roof and wall x-bracing provides longitudinal stability to the building. Portal frame bracings or minor axis moment resistance may also be used, if the openings are required. Transfers the wind load acting on building end walls to the foundations.
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Chapter – 4 ADVANTAGES OF PRE-ENGINEERED BUILDING SYSTEMS REDUCED CONSTRUCTION TIME Due to the systems approach, the use of high strength steel, use of tapered built-up sections which are optimized by the computerized design program and the use of continuous light gage secondary steel section, there is an overall reduction in steel weight, cost and time relative to conventional steel construction. Pre-engineered buildings are a predetermined inventory of raw materials that has proven over time to satisfy a wide range of structural and aesthetic requirements. The components are engineered beforehand and standardized. Use of these standard components reduces the engineering, production and erection time. Use of customized software for design & drafting increases the speed of the project. The production line is highly sophisticated, having Autowelders, multi-cutting torches, shear cutting machines etc., which greatly reduce the time of fabrication of built-up components. Roll forming machines for producing Z & C members and sheeting, having standard dimension, increases the production capacity of secondary members. Use of standard accessories greatly increases the speed of production & erection. Buildings are typically delivered in just a few weeks after approval of drawings. Foundation and Anchor Bolts are cast in parallel with manufacture of the building. Site assembly is fast, as all building components are delivered finished, ready for site bolting. Our study shows that in India the use of PEB will reduce total construction time on a project by at least 50%. This will allow faster occupancy and earlier realization of revenue. DESIGN Since PEB’s are mainly formed of standard sections and connections, the design time is significantly reduced. Specialized computer analysis and design programs optimize material require. Drafting also computerized using standard details that minimizes project custom details. The low-weight flexible frames offer higher resistance to seismic forces. LOWER COST Due to the systems approach, there is a significant saving in design, manufacturing and site erection cost. The structural elements are shaped to follow the stress diagram of the member, thus reducing weight, cost and load to foundations. The secondary members and cladding nest together reducing transportation cost. The overall price per square meter may be reduced as much as 30% lower than conventional steel.
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FOUNDATIONS Pre-engineered Buildings are about 30% lighter than the conventional steel structures. Hence, the foundations are of simple design, easy to construct and lighter weights. ERECTION Since all the connections of the different components are standard, the erection time is faster. FLEXIBILITY OF EXPANSION Buildings can be easily expanded in length by adding additional bays. Also, expansion in width and height is possible by pre-designing for future expansion. LARGE CLEAR SPANS Buildings can be supplied to around 90M clear spans. QUALITY CONTROL As buildings are manufactured completely in the factory under controlled conditions, the quality is assured. LOW MAINTENANCE Buildings are supplied with high quality paint systems for cladding and steel to suit ambient conditions at site, which results in long durability and low maintenance costs. ENERGY EFFICIENT ROOF AND WALL SYSTEMS Buildings can be supplied with polyurethane insulated panels or fiberglass blanket insulation to achieve required ‘U’ values. ARCHITECTURAL VERSATALITY Buildings can be supplied with various types of fascias, canopies, and curved eaves and designed to receive pre-cast concrete wall panels, curtain walls, block walls and other wall systems. SINGLE SOURCE RESPONSIBILITY As the complete building package is supplied by a single vendor compatibility of all the building components and accessories is assured. This is one of the major benefits of the pre-engineered building systems.
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Chapter – 5 APPLICATIONS OF PRE-ENGINEERED STEEL BUILDINGS
Warehouses Factories Workshops Offices Gas Stations Vehicle Parking Sheds Garages Supermarkets Showrooms Aircraft Hangers Schools Sports and Recreational facilities Labor Camps Low Cost Housing Hospitals Port houses Platform shelters etc
Some of the live examples are as follows:
Project:Office & Workshop Building , Courtesy: Kirby Building Systems
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Project:Shed , Courtesy: Kirby Building Systems
Project: Loco Sheds for Delhi Metro Rail Corporation, Courtesy: Kirby Building Systems
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Project: Delhi Metro Rail Corporation Stations, Courtesy: Kirby Building Systems
Project: Shell Petrol Station, Courtesy: Kirby Building Systems
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Project: North Eastern Council Assembly Buildings, Courtesy: Kirby Building Systems
Project: Nikhil Refineries Kakinada, A.P, Couurtesy: Kirby Building Systems ,.
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Project: Loco Sheds for Delhi Metro Rail Corporations, Courtesy: Kirby Building Systems
Project: GRSE Workshops, Courtesy: Kirby Building Systems
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Project: North Eastern Council Assembly Buildings, Courtesy: Kirby Building Systems
Project: Tata Holset Admin & Plant Bldg, Courtesy: Kirby Building Systems
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Project: Tata Holset Admin & Plant Bldg, Courtesy: Kirby Building Systems
Project: Reliance Petrol Stations, Courtesy: Kirby Building Systems
Project: Kirby Building Systems – Corporate Head Office
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Chapter – 6 PEB SYSTEMS IN INDIA Although PEB systems are extensively used in industrial and many other non-residential constructions world wide, it is relatively a new concept in India. These concepts were introduced to the Indian market lately in the 1990’s with the opening up of the economy and a number of multi-nationals setting up their projects. Global PEB players have established their presence in India by appointing local marketing agents and certified builders. But, Kirby Building Systems is the first PEB manufacturer to start manufacturing facility in India itself. It shows the commitment and conviction towards Indian market. Moreover, the state-of-the-art manufacturing facility at Hyderabad can produce up to 75,000 tones per annum. A full fledge Engineering and Marketing network is already established and have started working.
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Chapter – 7 WORKING WITH PEB SYSTEMS Following are some standard industry practices abroad, which will be adapted where required to suit Indian market conditions. The pre-engineered building manufacturers operate through network of Sales Offices and Certified Builders. The Builders are contractors who have been pre-qualified and certified by the PEB manufacturer and who have an exclusive contract with the manufacturer to sell and erect the buildings in a specific geographic region. Some builders also provide a turnkey service including civil works, mechanical and electrical services and finishing works when required by owner. The builder may either sign contract directly with the owner or with a general contractor appointed on the project. The owner may directly order the building from Kirby for supply only or through a Kirby builder for supply and erection. Building specifications and Architectural drawings meeting the functional and architectural requirements of the project are developed by the owner’s Architect / Engineer and issued with the bid documents. Kirby will prepare structural design and submit a proposal detailing scope of supply, specifications, price, delivery and proposal drawings based on the bid documents. Also wherever applicable, Kirby will submit alternative bids to reduce cost, for consideration by Engineer / Owner. Upon receiving a confirmed order, Kirby will prepare detailed design, structural design calculations and Approval drawings and submit for Engineer’s approval. Upon receipt of approval, Kirby will prepare shop drawings and construction drawings for fabrication and erection of the building. The anchor bolts plan stamped for construction alongwith the anchor bolts are typically delivered to site within 10 days of receipt of Approved drawings. Buildings upto about 300 MT are typically delivered to site within 6-8 weeks from date of approval.
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Chapter – 8 DESIGN OF PEB SYSTEMS PROGRAM OVERVIEW The main framing of PEB systems is analyzed by the Stiffness Matrix method using Kirby in-house software. The design is based on Allowable Stress Design (ASD) as per the American Institute of Steel Construction (AISC) specification. The design program provides an economic and efficient design of the main frames and allows the users to utilize the program in different modes to produce the frame design satisfying the engineer’s requirements. The program analyzes and designs the frame based on the given geometry and loading and the desired load combinations as specified by the building code opted by the user. The program operates through the maximum number of cycles specified to arrive at an acceptable design. DESIGN CYCLE The design cycle consists of the following steps: • • • • • • •
Set up section sizes and brace locations based on the geometry and loading specified for the frame design. Calculate moments, shears, and axial forces at each analysis point for each load combination. Compute allowable shear, allowable axial and allowable bending stress in compression and tension at each analysis point. Compute the corresponding stress ratios for shear, axial and bending based on the actual and allowable stresses and calculate the combined stress ratios. Decide the optimum splice locations and check to see whether the predicted sizes conform to manufacturing constraints. Using the web optimization mode, arrive at the optimum web depths for the next cycle and update the member data file. At the end of all design cycles, an analysis is run to achieve flange brace optimization.
FRAME GEOMETRY The program has the capability to handle different types of frame geometry as follows: • • • • •
Frames of different types viz. Rigid frames, Frames with multiple internal columns, Single slope frames, lean-to-frames, etc. Frames with varying spans, heights and slopes. Frames with different support conditions viz. Pin supports, fixed supports, sinking supports, supports with some degrees of freedom released etc. Unsymmetrical frames with off-centric peaks, unequal modules, varying slopes etc. User specified purlin and girt spacing & flange brace locations.
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FRAME LOADING Frame Design can handle different types of loading as described below: • • • •
•
• •
•
All the building dead loads due to sheeting, purlins etc., and the self weight of the frame. Imposed live loads on the frames with tributary reductions as applicable. Collateral loads such as false ceiling, light fixtures, A/C ducting loads, sprinkler systems, and any other suspended loads of similar nature. Wind loads input as basic wind speed or basic wind pressure will be converted to design wind pressure as per the building code specified by the user and shall be applied on different elements of the frame as per the coefficients corresponding to the user defined building code. The standard building codes like MBMA, UBC, ANSI, ASCE etc., are built in to the program and the program can automatically pick the coefficients for these codes. For special codes, however, the program offers the option for the user to input the coefficients as required. Crane and non-crane special loading can be specified by the user and the program has the capability to handle these special loads and combine them with the other loads as desired by the user. Seismic loads corresponding to different zone categories of various international codes can also be defined and combined with other load cases as required. Temperature loads can also be specified in the form of the differential temperature value in Centigrade and specifying the appropriate coefficient for thermal expansion. Load combinations with appropriate load factors can be specified by the user as desired.
DESIGN CODES Following design codes are used as applicable to the project: AISC
American Institute of Steel Construction Manual
AISI
American Iron and Steel Institute Specifications
MBMA
Metal Building Manufacturer’s Association Low Rise Building Systems Manual.
ANSI
American National Standards Institute Specifications
ASCE
American Society of Civil Engineers
UBC
Uniform Building Code
IS
Indian Standards
Other codes as specified in the contract
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DESIGN CRITERIA Design Method
Allowable stress design method is used as per AISC specifications.
Deflections
Unless otherwise specified, the deflections will be to Kirby standards, which are based on MBMA and AISC criteria and standard industry practices.
Primary Frames
Moment Resisting Plane Frames with pinned or fixed bases.
Secondary Framing
Cold-Formed Z-sections for purlins and girts designed as continuous beams spanning over rafters and columns with laps.
Longitudinal Stability
Wind load on building end walls is transferred through roof purlins to braced bays and carried to foundations through diagonal bracing.
DESIGN SOFTWARE Kirby uses the following main design software for the Design for pre-engineered buildings: PACE II: proprietary design software specifically developed in U.S. for PEB and customized to Kirby standards. COMPUFRAME: Design software developed in U.S. for frame analysis and design. STAAD Pro: Design software for structural analysis and design.
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DESIGN PROCESS The frame data is assembled based on the number of frame members, number of joints, number of degrees of freedom, the conditions of restraint and the elastic properties of the members. Based on this, the data is stored and the member section properties are computed. The overall joint stiffness matrix is generated based on the above frame data by summation of the individual stiffness matrices considering all possible displacements. The load vector is then generated based on the loading data and the unknown displacements are obtained by inverting the overall joint stiffness matrix and multiplying with the load vector. Knowing the free joint displacements, the member end actions are obtained by back substitution. The axial, shear and bending forces are then transformed to the section neutral axis and the additional moment created by the eccentricity of the thrust is added to the moment value. These values are generated for different load combinations and the final design checks are performed. The allowable stress values are computed as per the AISC specification with due consideration for the web depth/thickness ratios and the flange width/thickness ratios with the appropriate correction factors as per AISC. For computation of the allowable bending stresses, the effective un-braced lengths for each segment are used based on the brace point locations defined by the user. The effective length factor K is used for calculating the slenderness ratios in order to compute the allowable axial stresses. The coefficients for bending are calculated based on the end conditions for each member and the corresponding end moment values. The stress ratios are then computed as actual/allowable stresses and are then combined to check that the total aggregate value is under unity. The joint displacements and support reactions are reported for various load cases and combinations along with the clear heights at haunch and peak to check for clearances. A detailed connections report is generated based on the forces acting at all the splice joints and designed as per the specifications of AISC. The connections used in the super structure for all the main frame splices conform to the specifications of ASTM A 325 for High strength friction grip bolts. The anchor bolts will be of ASTM A 307 material Grade 36.
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SERVICEABILITY CRITERIA Unless otherwise specified by client, the serviceability criteria are based on MBMA and AISC specifications and standard industry practices. Following are the brief extracts from these specifications. Roof Purlins supporting roof panels:
L/150 max.
Wall Girts supporting wall cladding:
L/120 max.
Rafter Peak Deflection:
L/180 max.
Rafters supporting plastered ceilings:
L/360 max. Under live load
Bare frame drift (Sway):
H/60 to H/100 max
Bare frame drift for frames supporting cranes: - Top running Cab operated: - Top running Pendant operated: - Crane Runway Beams:
Mezzanine supporting Beams & Joists:
H/240 H/100 L/400 max. Horizontal L/600 max. Vertical L/240 max. Under Dead & Live load L/360 max. under LL only
When client requires the serviceability criteria as per IS codes, the design deflections will be compiled accordingly.
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Chapter – 9 MATERIALS AND FABRICATION All materials are purchased new direct from the steel mills with certified Mill certificates complying with ASTM or equivalent specifications. Kirby maintains a large stock of Plates, Bars, Black coils, Galvanized coils, Sheeting coils and various building accessories required to support the production levels. All the material specifications are documented in the Company’s Specification Manual, which is an integral part of the total quality control system at Kirby. High strength steel having minimum yield strength of 345 Mpa is used for primary, secondary and cladding. The materials are subject to stringent quality control checks upon receipt at plant and only upon approval are taken into stock. The material inspection system is well documented in Kirby Quality Control Manual and complies with material traceability and other requirements specified in ISO9001. The manufacture of the building is done in accordance with relevant American Codes. Welding is performed by pre-qualified welders using approved welding processes as per structural welding code AWSD1.1 published by the American Welding Society. The built-up sections are welded in an automatic Conrac welder using submerged arc welding process. The splice plates and other attachments are welded by the Innershield or CO2 welding process. All butt welds are full penetration welds. Stage inspections are carried out at various stages in the manufacturing process and results documented. The welds are subject to NDT tests including Dye penetrant inspection (DPI), Magnetic particle Inspection (MPI),Ultrasonic Testing (UT) or Radiography, as required by contract specifications. A 100% visual and dimensional check is performed on all members. Manufacturing tolerances are in accordance with MBMA and AWS specifications. The standard surface treatment for fabricated steel is mechanical wire brushing to SSPC ST3 and application of one coat of red oxide prier to a nominal dry film thickness of 25 microns. However Kirby offers various types of surface preparation and epoxy paint systems to suit the corrosive conditions at site and contract requirements. Kirby has blast cleaning facility to achieve a white metal finish to Swedish standard SA3 and airless spray facility to apply any specified paint system. Upon request Kirby will recommend the optimum paint system to suit ambient conditions at site.
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Chapter – 10 SITE ERECTION Kirby provides Erection drawing and procedures manual, which includes all the information required for the site assembly of the building. The erector must use the proper tools and equipment and sequence of erection as specified in Kirby manual. The high strength bolts at the primary connections are pre-tightened to specified tension or torque as shown in the erection drawings. The method of tightening may be either using a calibrated tension or torque wrench or turn-of-the-nut method as specified in AISC Manual. Erection should always start with a braced bay and the red steel must be fully plumbed before starting cladding erection. Erection tolerances are as set forth in AISC Code of Practice except individual members are considered plumb and aligned if the deviation does not exceed 1:300 as per MBMA specifications.
Chapter – 11 WARRANTY Kirby provides a standard one-year warranty from date of shipment against defective materials and workmanship. Extended warranty on cladding can be provided based on the type of coating specified and the requirement of the contract.
Chapter – 12 CONCLUSION The foregoing is a brief overview of the Pre-Engineered building system. For further details, you may please refer to the Kirby Technical Manual and other company brochures.
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Reference Books & Codes: 1.
Metal Building Systems Design & Specifications By: Alexander Newman Publisher: McGraw-Hill, 11 West 19th street, New York, NY 10011
2.
MBMA: Metal Buildings Manufacturers Association, Low Rise Building Systems Manual 2002. 1300, Summer Ave, Cleveland, Ohio 44115.
3.
AISC: American Institute of Steel Construction, Manual of Steel Construction, Allowable Stress Design, Ninth Edition 1989.
4.
AWS-D1.1-2004: American Welding Society, Structural Welding Code Steel Manual 2004.
5.
IS: 800 – 1984, Indian Standards Code of Practice for General Construction in Steel
6.
AISI: American Iron & Steel Institute, Cold Formed Steel Design Manual, 1996 Edition.
7.
IS: 875 Part 3 – 1987 Indian Standards Code of practice for Design Loads for Bldgs & Structures(Other than Earthquake)
8.
UBC: Uniform Building Code 1997
9.
ASCE 7-95: American Society of Civil Engineers, Minimum Design Loads for Buildings and Other Structures
10.
BSI CP3: Chapter V: Loading Part 2: 1972 Wind Loads
11.
BSI 6399: Part 3: 1988, Code of practice for imposed roof loads (snow loads)
12.
BSI 6399: Part I: 1984, Code of practice for dead and imposed loads.
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About The Author S. Khalid Hashmi is working as Deputy General Manager – Technical Services in Kirby Building Systems India Ltd. He is the Head of Product & System Development group and involved in Planning, Coordination and Checking of Design works and introduction of new Products and systems for the company. Basically, he is a Structural Engineer and has about 19 years of experience out of which 13 years of overseas experience in different Multi-National Pre-Engineered Steel Building Companies. He started his career in Pre-Engineered Steel Industry as a Senior Design Engineer. He was involved in preparing and checking the designs of Pre-engineered Steel Structures of Complex Buildings, Design Training and in the preparation of Design & Drafting Procedures Manuals.
Kirby Building Systems India Ltd. KIRBY BUILDING SYSTEMS - INDIA LTD (ISO-9001 Certified), is an affiliate of Alghanim Industries -Kuwait, multinational organization with diverse interests in industrial and consumer products. The name KIRBY has become so well known that it is accepted as the generic term to describe steel buildings throughout the Middle East and other parts of the World. KIRBY BUILDING SYSTEMS began manufacturing pre-engineered steel buildings in Kuwait in 1976 and has a set up a state-of-the-art pre-engineered steel building plant at Pashamylaram near Hyderabad, Andhra Pradesh. Further, considering the customer’s requirements, KIRBY is setting up a new pre-engineered steel building plant at Haridwar. KIRBY is the premier producer of steel buildings in the Middle East and South West Asia. Over the years KIRBY has earned a remarkable reputation for providing cost effective solutions for buildings manufactured to the highest standards and suited to all environments. KIRBY operates from all the major cities of India. The manufacturing facilities have a production capability to produce hundreds of custom designed steel buildings each year. KIRBY people are all dedicated to provide buildings specifically designed to your requirements. Skilled structural engineers familiar with state-of-the-art technology are part of the KIRBY team. Our professionals use the very latest in computerized engineering design and drafting systems, permitting the selection of the most economical and efficient framing systems, as well as accurate design and drawings. Other skilled technicians also use computerized systems for estimation, inventory control, job tracking, scheduling and accounting applications. Courtesy of the computer, quotations are provided in just a few days for even the more complex projects.
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Quality assurance at KIRBY is a total system of management, which applies as much to initial design as to final construction. Skilled structural engineers, talented designers and professional managers consistently make KIRBY your first choice when it comes to your building. The KIRBY product range is broad and diversified. Primary framing systems are available in clear span rigid frames, beam and column frames, space saver frames, single slope, multi-span and lean-to frames. These framing systems are available in a variety of sidewall heights, bay spacings, and loading conditions, including seismic loads. The high quality and attractive Kirby-Rib Roof Panel and Kirby Architectural Wall Panel complement the various framing systems. For those clients requiring special Architectural features, Kirby offers a complete line of fascias, canopies, roof overhangs, parapet walls, and curved panels. Kirby offers rock wool blanket insulation and a wide variety of accessories such as skylights, wall lights, roof vents, wall louvers, windows, personnel doors and sliding doors. Kirby buildings are ideally suited for a wide range of uses, such as manufacturing, warehouses, supermarkets, auto agencies, commercial buildings, recreational buildings, camps workshops, and agricultural buildings. Research and development of new products used in the buildings play a particularly important role within the company. KIRBY is constantly improving its products. We listen to our clients when we consider new product lines and product improvements. The stamp represents KIRBY’S commitment to Total Quality Control. Every major fabricated steel section must be approved before it is stamped by one of our qualified inspectors. KIRBY uses the latest test methods, including ultrasonic and radiographic equipment. In addition, the Total Quality Control System ensures that all purchased materials received are exactly to our high quality specifications and that it is manufactured exactly to KIRBY’s Quality Control Standards. KIRBY appoints, trains and certifies a highly experienced team of local builders who work closely with the company to offer the client efficient and economical construction service. KIRBY builders also become involved in much more than merely erecting a building. Many are capable of offering complete turnkey construction services. KIRBY BUILDING SYSTEMS – INDIA LTD Plot No.: 8 to 15, IDA Phase III, Pashamylaram, Medak Dist. - 502 307. Andhra Pradesh. Tel: (08455) 226901/2/3/4 Fax: (08455) 226887/226919 e-mail :
[email protected] Website : www.kirby-india.com
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