C Purlin Design
April 8, 2021 | Author: Anonymous | Category: N/A
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DESIGN OF PURLINS (COLD FORM SECTION) Purlin Designation P1
Modified By: Multibuild Consultants, Va JOB No.: DATE :
Input Data: Purlin Geometry Span of the purlin Spacing of the purlin No. of Sag rods Slope of the Roof
= = = =
5.500 M 1.15 M 1 10 deg.
Number of Spans = (for 1 or 2 spans, Bending Moment Coefficient is 8, for 3 or more spans, it is 10) (in case of Bending about minor axis, (No of spans)x(No of sagrods+1) is used.
3
Input Data: Loads Dead Loads Weight of Sheeting Self Weight of Purlin Extra for cleats, as % of Purlin weight Additional Dead Loads to Consider
= = = =
6 kg/sqm Automatically Calculated from Section properties 10 % 4 kg/sqm
Live Loads Live load on Roof
= Automatically Calculated from Slope = 75 kg/sqm Additional Live Loads to be considered = 0 kg/sqm (For Design of Wall Girt (Cladding Runner), additional Live loads to be considered can be entered as -ve of LL on roof) (Live load will be 0 effectively) Wind Loads Basic Wind Speed 44 m/s Terrain Category 3 k1 1 Maximum Horizontal Dimension of Building 44 m k3 1 Hence, Bldg Class B Height of Top 8.25 m Based on the data on right, k2 is obtained from the tables k2 0.88 Ht of building at eaves level, h Width of the building, w Length of the Building, l Hence, h/w and l/w
= =
= = =
6.35 m 24 m 44 m 0.265 1.833
Based on the h/w and l/w, the values of Cpe is obtained from tables as noted below: Maximum Downward Cpe (include sign) -1.2 Maximum Upward Cpe (include sign) -0.8 Based on % of openings, Cpi is taken as +/-
0.7
y: Multibuild Consultants, Vapi 26.MBC.MWV.FGPM3 16-06-2017
ion properties
of LL on roof) will be 0 effectively)
Input Data: Purlin Section Being Checked Try
C 200x50x20x3.15
Yield stress of material Flange Width, b Depth of section d Thickness t Length of Lip lip_l Inner Bending Radius
2400 50 200 3.15 20 4.73
Area Zxx Zyy Ixx Iyy
9.86 53.50 7.89 535.00 29.20
Purlin Weight
KG/CM2 mm mm mm mm mm cm2 cm3 cm3 cm4 cm4
Section Modulus about Major Axis Section Modulus about Minor Axis Moment of Inertia about Major Axis Moment of Inertia about Minor Axis
7.740 kg/sqm
Output Summary Section Properties OK?
Stresses Ok? Critical Stress Factor Deflection Check OK?
OK OK
Based on Section 9 of BS:5950 Part 5 – 1998 Based on IS 801 Clause 5.2.2.1
Ok 0.999 OK
Notes:
1. Section Properties Check based on Section 9 of B:5950 Part 5 is a guideline and not mandatory Hence, Design is considered Safe even if above check only is not okay but all other che 2. Currently, this design only works if full width is effective. If full width is not effective, this spreadsheet will report Failure in Stress Check 3. Not suitable currently for curved roofs. 4. Design is not suitable for varying spans of purlins (varying truss spacing)
e and not mandatory okay but all other checks are okay effective,
Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd Cold Form Purlin Design Report
Modified By: Multibuild Consultants, Vapi User: Arif
Code Version: R1
Code Year: 2011
Revision History
R0: Basic Design with checks for Stresses and Deflection based on IS 800 only R1: Added Section property checks and Allowable Stress Calculations based on IS 801
JOB No.:
26.MBC.MWV.FGPM3
DATE :
16/6/17
Input Data: Purlin Geometry Span of the purlin Spacing of the purlin No. of Sag rods Slope of the Roof
= = = =
5.500 M 1.15 M 1 10 deg.
Number of Spans
=
3
Bending Moment Coefficients: Use 8 for Single/Two spans, 10 for 3 or more spans Bending Moment Coefficient for Mxx(BMCX) For Bending About Minor Axis, Number of spans= number of spans x (number of sagrods+1) Number of Spans about Minor Axis = Bending Moment Coefficient for Myy(BMCY) TRY PURLIN SIZE C 200x50x20x3.15 (IS 811) Cross Sectional Area of Purlin = Purlin Weight
10 6 10
9.86 cm2 7.740 kg/m 6.731 kg/sqm
=
(Area in sqcm x 0.785 kg/sqcm/m) in kg/m (Weight in kg/m)/spacing
Design Calculations: Primary Load Cases DEAD LOAD Weight of Sheeting Self Weight of Purlin (calculated above) Extra load for weight Other Dead Loads
6.000 6.731 0.673 4.000
10 % of purlin weight
Total Dead Load =
kg/sqm kg/sqm kg/sqm kg/sqm
17.404 kg/sqm 0.174 kN/sqm
LIVE LOAD Live Load on Roof = 75 kg/sqm if slope is less than 10 degrees. If Slope is more than 10 degrees, LL = 75 – 2x(slope-10), subject to minimum of 40 kg/sqm Live load on Roof
75 KG/M2
=
Additional Live Loads to be considered = (For Design of Wall Girt (Cladding Runner), additional Live loads to be considered can be entered as -ve of LL on roof) Total Live Load =
0 KG/M2
75 kg/sqm 0.750 kN/sqm
WIND LOAD Basic Wind Speed Vb k1 k3
44 m/s 1 1
Terrain Category Maximum Horizontal Dimension of Building Hence, Building Class is Height of Top
3 44 m B 8.25 m
Based on the above data, k2 is obtained from the tables k2 0.88 Design Wind Speed Vz=k1.k2.k3.Vb Design Wind Pressure pz=0.6Vz^2 = Ht of building at eaves level, h
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38.72 m/s 899.543 N/sqm 0.900 kN/sqm =
6.35 m
Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd Width of the building, w Length of the Building, l Hence, h/w and l/w
= = = =
Based on the h/w and l/w, the values of Cpe is obtained from tables as noted below: Maximum Downward Cpe (including sign) Maximum Upward Cpe (including sign) Based on % of openings, Cpi is taken as +/-
24 m 44 m 0.265 1.833
-1.2 -0.8 0.7
Wind Load is included in two load combinations – DL+WL and DL+LL+WL Since, Dead Load and Live Load are downward, DL+WL will be critical for the maximum upward wind force Similarly, DL+LL+WL will be critical for the maximum downward wind force WL1: Maximum Upward Wind Force – To be used in combination DL+WL1 Maximum Upward Cpe (including sign) Cpi to use (for upward, use -)
-1.2 -0.7
Hence, Cpe+Cpi =
-1.9
Design Wind Pressure pz
0.900 kN/sqm
Wind pressure for Purlin Design
-1.709 kN/sqm
WL2: Maximum Downward Wind Force – To be used in combination DL+LL+WL2 Maximum Downward Cpe (including sign) Cpi to use (for upward, use -)
-0.8 0.7
Hence, Cpe+Cpi =
-0.1
Design Wind Pressure pz
0.900 kN/sqm
Wind pressure for Purlin Design
-0.090 kN/sqm
Design Calculations: Primary Load Cases – Conversion of forces to Normal And Tangential Components Spacing of the purlin Slope of the Roof
= =
1.15 m 10 degrees
Total Dead Load
=
0.174 kN/sqm
DL Normal Component = DL x Spacing x cos(slope) = DL Tangential Component = DL x Spacing x sin(slope) =
0.197 kN/m 0.035 kN/m
Total Live Load
0.750 kN/sqm
=
LL Normal Component = LL x Spacing x cos(slope) = LL Tangential Component = LL x Spacing x sin(slope) = Total Wind Load in WL1
=
0.849 kN/m 0.150 kN/m -1.709 kN/sqm
WL is normal to roof Hence, WL1 normal component = WL1 x Spacing = And, WL1 Tangential component =
-1.966 kN/m 0.000 kN/m
Total Wind Load in WL2
-0.090 kN/sqm
=
WL is normal to roof Hence, WL2 normal component = WL2 x Spacing = And, WL2 Tangential component =
-0.103 kN/m 0.000 kN/m
Design Calculations:Summary of Loads in Load Combinations From above calculations, the components of load in the various load combinations are tabulated
Page 6
Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd DL+LL Normal Load Tangential Load
DL+WL1 1.046 0.185
-1.768 0.035
DL+LL+WL2 0.943 kN/m 0.185 kN/m
For Strength Design, 0.75 factor is applicable for combinations with Wind Load since 33.33% extra stress is allowed Hence, the components of load in the various load combinations for Strength design are DL+LL 0.75(DL+WL1) 0.75(DL+LL+WL2) Normal Load 1.046 -1.327 0.707 kN/m Tangential Load 0.185 0.026 0.138 kN/m Maximum Normal Component =
1.046 kN/m
Purlin Section Selected: Section Name
C 200x50x20x3.15
Yield stress of material Flange Width, b Depth of section d Thickness t Length of Lip lip_l Internal Bending radius Total bending Radius, rad
2400 50 200 3.15 20 4.73 7.88
Flange Width w/o bend, w = b – 2 x rad
34.24 mm
Purlin Weight
kg/sqcm mm mm mm mm mm mm
Area
9.86 cm2
Zxx
53.50 cm3
Zyy
7.89 cm3
Ixx
535.00 cm4
Iyy
29.20 cm4
= =
7.740 kg/m 6.731 kg/sqm
(Area in sqcm x 0.785 kg/sqcm/m) in kg/m (Weight in kg/m)/spacing
Design Calculations: Checking Basic Section Properties based on Section 9 of BS:5950 Part 5 – 1998 Check No. 1 – Overall Depth =L/45
Overall Depth 100t = L/45 =
200 mm 315 mm 122.222 mm
Hence
Ok
Check No. 2 – Overall Width of Compression Flange= b/5
Width of Lip B/5 =
20 mm 10 mm
Hence
OK
Check No. 4 – Total Width over both flanges >= L/60
Total Width over both flanges L/60 = Hence
96.85 mm 91.667 mm OK
Check No. 5 – Zxx of Purlin >= WL/1400 for Simply Supported Purlin and >=WL/1800 for Continuous Purlin
Zxx
=
53.50 cm3
W is normal component of unfactored distributed dead load plus imposed load in kN L is span of purlin in mm W= 5.756 kN
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Z Purlin Design Created Report by Madurai ES Consultancy Services Pvt Ltd L= Number of Spans = Hence, denominator =
5500 mm 3 1800
WL/denominator
17.587
Hence
Ok
Result 1: Check for Section Properties Based on BS 5950 Part 5 Sec.9:
OK
Design Calculations: Checking Basic Section Properties based on IS 801 for Lip of Purlin Minimum Depth of Lip shall be 2.8 x t x ((w/t)^2-281200/Fy)^(1/6) and not less than 4.8t t= w= Fy= w/t= 2.8 x t x ((w/t)^2-281200/Fy)^(1/6) 4.8t=
3.15 34.24 2400 10.87 8.810 15.12
Lip l=
mm mm kg/sqcm mm mm
20 mm
Hence
Ok
Lip is Edge stiffener only if w/t
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