Wind Load Calculations
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Calculat i on of W i nd Load Wind load is calculated following BNBC 1993. The assumed location of the project is Chittagong. Basic wind speed is 280 kilometer per hour (80 m/sec) .Exposure category is assumed ―A-III‖. Now sustained wind pressure, q z =C c C I C z V b 2 Where, q z =sustained wind pressure at height z, KN/m2. C I = structure importance coefficient (1.0 for special category structure). C c =velocity to pressure conversion coefficient=47.2×10 -6 . C z =combined height and exposure coefficient. V b = basic wind speed in km/hour. Design wind pressure, P z =C G C p q z Where, P z =design wind pressure at height z, kN/m2 C G =gust coefficient C p =pressure coefficient for structure or components q z =sustained wind pressure Pressure coefficient C p : Length of building =81.5 meter. Width of building =57.5 meter. Height of building = 28 meter. For wind perpendicular to length, h/B= 28/81.5=0.343 and L/B=57.5/81.5=0.705 For wind perpendicular to width, h/B= 28/57.5=0.487 and L/B=81.4/57.5=1.415 Now from table 6.2.15 of BNBC 1993 we get by interpolation, C p =1.52 when wind perpendicular to building length. C p = 1.24 when wind perpendicular to building width. Design wind pressure:
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Description of wind calculation of a 7 storied garments buildings
Transcript of Wind Load Calculations
Calculat i on of W i nd Load
Wind load is calculated following BNBC 1993. The assumed location of the project is Chittagong. Basic wind speed is 280 kilometer per hour (80 m/sec) .Exposure category is assumed ―A-III‖.
Now sustained wind pressure, qz=CcCICzVb2
Where,
qz =sustained wind pressure at height z, KN/m2.
CI= structure importance coefficient (1.0 for special category structure). Cc=velocity to pressure conversion coefficient=47.2×10-6
.
Cz=combined height and exposure coefficient. Vb= basic wind speed in km/hour.
Design wind pressure, Pz=CGCpqz
Where,
Pz=design wind pressure at height z, kN/m2
CG=gust coefficientCp=pressure coefficient for structure or components qz =sustained wind pressure
Pressure coefficient Cp:
Length of building =81.5 meter. Width of building =57.5 meter. Height of building = 28 meter.
For wind perpendicular to length, h/B= 28/81.5=0.343 and L/B=57.5/81.5=0.705
For wind perpendicular to width, h/B= 28/57.5=0.487 and L/B=81.4/57.5=1.415
Now from table 6.2.15 of BNBC 1993 we get by interpolation,
Cp=1.52 when wind perpendicular to building length.Cp= 1.24 when wind perpendicular to building width.
Design wind pressure:
Now design wind pressures are calculated at different height for wind perpendicular to building length and wind perpendicular to building width as shown in Table A and Table B.
Table A Design wind pressure (wind perpendicular to building length)
Height aboveground level, z
(meter)
Cz Sustained windpressure, qz=CcC1CzVb2
(kN/m2)
CG Design windpressure, Pz=CGCpqz
(kN/m2)0-4.5 0.368 1.36 1.654 3.42
6 0.415 1.54 1.592 3.729 0.497 1.84 1.511 4.22
12 0.565 2.09 1.457 4.6315 0.624 2.31 1.418 4.9818 0.677 2.51 1.388 5.2921 0.725 2.68 1.363 5.5624 0.769 2.85 1.342 5.8027 0.81 3.00 1.324 6.0330 0.82 3.03 1.34 6.18
Table B Design wind pressure (wind perpendicular to building width)
Height aboveground level, z
(meter)
Cz Sustained windpressure, qz=CcC1CzVb2
(kN/m2)
CG Design windpressure, Pz=CGCpqz
(kN/m2)0-4.5 0.368 1.36 1.654 2.79
6 0.415 1.54 1.592 3.03 9 0.497 1.84 1.511 3.45
12 0.565 2.09 1.457 3.78 15 0.624 2.31 1.418 4.06 18 0.677 2.51 1.388 4.31 21 0.725 2.68 1.363 4.53 24 0.769 2.85 1.342 4.74 27 0.81 3.00 1.324 4.92 30 0.82 3.03 1.34 5.04
