Wind Load Calculation With 0.3W Effect
Wind Load Calculation With 0.3W Effect
Wind Load Calculation With 0.3W Effect
2022
Design :- 5x2 Double portrait Structure Rev :- 0
Rear Leg
Pressure Coefficent for C Channel (Please refer As IS 875 Part 3 TABLE 29)
Cfn= 2.05 - for web side
Cft= 0.6 - for flange side
Front Leg
Pressure Coefficent for C Channel (Please refer As IS 875 Part 3 TABLE 29)
Cfn= 2.05 - for web side
Cft= 0.6 - for flange side
Rafter
Pressure Coefficent for C Channel (Please refer As IS 875 Part 3 TABLE 29)
Cfn= 2.05 - for web side
Cft= 0.6 - for flange side
Side Bracing
Pressure Coefficent for L Angle (Please refer As IS 875 Part 3 TABLE 29)
Cfn= 2.1 - for leg side
Cft= 1.8 - for leg side
Back Bracing
Pressure Coefficent for L Angle (Please refer As IS 875 Part 3 TABLE 29)
Cfn= 2.1 - for leg side
Cft= 1.8 - for leg side
Reduction Factor K for Individual Members
Please refer As IS 875 Part 3 TABLE 28
Along X direction (Rear Leg)
l/b Ratio 39.80
Flange of Rear Leg Member Perpendicular to wind direction 0.87
Along X direction (Front Leg)
l/b Ratio 28.78
Flange of Front Leg Member Perpendicular to wind direction 0.84
Along X direction (Back Bracing)
l/b Ratio 99.15
Leg of Back Bracing Member Perpendicular to wind direction 0.95
Along Z direction (Rear Leg)
l/b Ratio 22.742857
Web of Rear Leg Member Perpendicular to wind direction 0.82
Along Z direction (Front Leg)
l/b Ratio 16.442857
Web of Front Leg Member Perpendicular to wind direction 0.77
Along Z direction (Rafter)
l/b Ratio 50.742857
Web of Rafter Member Perpendicular to wind direction 0.9
Along Z direction (Side Bracing)
l/b Ratio 41.35
Leg of Side Bracing Member Perpendicular to wind direction 0.87
Force Per meter calculation for X and Z direction
For X +ve Direction or -ve Direction
Force on Rear Leg Member along the Flange 0.02 kN/m
Force on Front Leg Member along the Flange 0.02 kN/m
Force on Back Bracing Member along the (Leg) Wind direction 0.06 kN/m
For Z +ve Direction or -ve Direction
Force on Rear Leg Member along the Web 0.09 kN/m
Force on Front Leg Member along the Web 0.09 kN/m
Force on Rafter Member along the Web 0.10 kN/m
Force on Side Bracing Member along the (Leg) wind direction 0.06 kN/m
Project :- Hatsun Agro, Govindapur (RCC) Date :- 21.02.2022
Design :- 5x2 Double portrait Structure Rev :- 0
Reference: Loading as per IS 875 2015 Page No. 17, Table No. 8 Note 1
As per the note 1, For monopitch canopies the centre of pressure should be taken to act at 0.3w
from windward edge.
Sample Calculation for Windward Side Load
CASE - I
48
2 .928=
7 9 2 .=279
2 1 W 8
4 - 12.64 -- .09.834
6 . 2
4.2 4 W
792 2
1.2 W 79
0.13.2
©For calculating the wind load acting on the covered area of windward/Leeward side &
transferring the same load on purlins, the calculations are as follows:
üFormula for working out Force from IS875 2015:
F = (Cpe – Cpi) x A xPdi
üIn STAAD the load applied to Purlins is in the form of UDL. Hence the loading has to be
worked out in kN/m
UPWARD FORCE - I
8
.2 79 2 = 2.988448
1 .9
4.264 -- 1.2792 = 2
4.264
1.2792
1.2792
-15.98 kN
4.2
4.2
8.88 kN
= 2.9848
1.2792
4.264 -
1.2792
4.2
100 Important buildings and structures such as hospitals 100 1.05 1.06
communication buildings / towers, power plant structures
N DIFFERENT WIND SPEED ZONES Wind Load
km/h
44 47 50 55 140.4
4 5 6 7 158.4
1 1 1 1 169.2
Cft= 0.60
Pressure Coefficent for L Angle Pressure Coefficent for C Channel (Equal)
2.10 2.05
1.80 2.05
Cfn Cft
Pressure Coefficent for C Channel - for web side - for flange side
Pressure Coefficent for L Angle - for leg side - for leg side
Pressure Coefficent for C Channel (Equal) - for web side - for flange side