BNBC 2017 Wind Load Provision comes from ASCE 7-05
Reference ASCE 7-05 code link: https://drive.google.com/file/d/1zmgdxEY6wcfMj4fmu2daDlmXr5SJ14QX/view?usp=sharing
Example:
It is required
to calculate the lateral wind loads acting on the 8-story building, considering
the wind is acting first in the North-South direction. The building which is
used as headquarter for police operation, is 30 m x 15 m in plan as shown in
the figure (enclosed), and located right on the Gaza Beach (flat terrain).
Note: Use a
basic wind speed of 100 Km/hr and
ASCE 7-05 Directional Procedure.
PLAN |
Elevation
Step 1: Building risk category:
Based on Table 1.5-1, the Building risk category is IV.
Step 2: Basic wind
speed:
It is given as 100 km/hr.
Step 3: Building wind load parameters:
- Kd = 0.85 (wind directionality factored evaluated from Table 26.6.1)
- Exposure category is D
- Kzt =1.0 (Topographic factor for flat terrain)
- Gust factor, G, is 0.85 for rigid buildings
- Building is enclosed
- Internal pressure coefficient for enclosed buildings, 𝐺𝐶𝑝𝑖, is ± 0.18
Step 4: Velocity pressure coefficients,
Kh =1.384 (Interpolating from Table 27.3-1) and Kz varies with height
For L / B = 15/30 = 0.5 and using Figure 27.4.1, the external pressure coefficients are shown in the
figure.
Height, meters
|
Kz
|
qz
|
p
|
0 to 4.6 m
|
1.03
|
414.17
|
366.76
|
4.6 to 6.1m
|
1.08
|
434.17
|
380.36
|
6.1 to 7.6 m
|
1.12
|
450.28
|
391.32
|
7.6 to 9.1 m
|
1.16
|
466.39
|
402.27
|
9.1 to 12.2 m
|
1.22
|
490.56
|
418.71
|
12.2 to 15.2 m
|
1.27
|
510.56
|
432.31
|
15.2 to 18 m
|
1.31
|
526.67
|
443.26
|
18 to 21.3 m
|
1.34
|
538.89
|
451.57
|
21.3 to 24.4 m
|
1.38
|
554.72
|
462.34
|
24.4 to 25 m
|
1.40
|
562.78
|
467.82
|
Thanks
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