1. SESSION 7 Applications of ASCE 7-10: Low-Rise Building
ASCE Wind Loads

2. Low-rise Metal Building
250 ft
25 ft
20 ft 12 4
200 ft
100 ft
Wind Truss
Ridge
Frame
Purlin
Eave
Girt
Wall Cable/Rod
Bracing
53.3 ft
ASCE Wind Loads

3. ASCE Wind Loads

4. ASCE Wind Loads

5. ASCE Wind Loads

6. ASCE Wind Loads

7. Loading Cases for MWFRS
FIG , p 214
MWFRS of buildings of all heights shall be designed for Load Cases in Fig
Consider all four load cases unless exceptions are met
The metal building shown is normally designed without diaphragms
Load Cases 2 and 4 do not apply
ASCE Wind Loads

8. ASCE Wind Loads

9. Basic Load Cases: Fig 28.4-1, p 242 (see Note 8, p243)
LOAD CASE A
LOAD CASE B
ASCE Wind Loads

10. P 243
ASCE Wind Loads

11. (GCpf) LOAD CASE A (GCpf)s for wind parallel to ridge (LOAD CASE A)
Building Surface
(degrees) 1 2 3 4 5 6 1E 2E 3E 4E
0-5
.40
-0.69
-0.37
-0.29
-0.45
0.61
-1.07
-0.53
-0.43
18.4*
.52
-0.47
-0.42
0.78
-0.67
-0.62 20
.53
-0.48
0.80
-0.64
(GCpf )s for wind normal to ridge (interpolated for 18.4 degrees)
ASCE Wind Loads

12. * positive internal pressure
ASCE Wind Loads

13. ASCE Wind Loads

14. * positive internal pressure
Calculate pressures for “wind blowing primarily parallel to ridge”:
p = qh [(GCpf) – (GCpi)]
= 18(GCpf) – (For positive internal pressure)
Example: Zone 3: GCp = (page 6-18)  = 0º
p = 18(-0.37) – 3.2 = -9.9 psf
Each corner of the building must be considered, in turn, as illustrated in Fig This action makes a total of 8 load cases for positive internal pressure.
There are an additional 8 load cases for negative internal pressure for a total of 16 load cases.
* positive internal pressure
ASCE Wind Loads

15. ASCE Wind Loads

16. COMPARISON OF METHODS MWFRS METAL BUILDING
CHAPTER 28
ENVELOPE METHOD
CHAPTER 27
DIRECTIONAL METHOD
ASCE Wind Loads

17. SIMPLIFIED METHODS
From Significant Changes to the Wind Load Provisions of ASCE 7-10, p 85 (that you have) it is stated
ASCE Wind Loads

18. ASCE Wind Loads

19. ASCE Wind Loads

20. ASCE Wind Loads

21. NEW SIMPLIFIED METHOD FOR 60 ft < h < 160 ft
CHAPTER 27 IN ASCE 7-10
ASCE Wind Loads

22. ASCE Wind Loads

23. ASCE Wind Loads

24. ASCE Wind Loads

25. ASCE Wind Loads

26. ASCE Wind Loads

27. WIND TUNNEL TEST SAMPLES
ASCE Wind Loads

28. ASCE Wind Loads

29. ASCE Wind Loads

30. ASCE Wind Loads

31. ASCE Wind Loads

32. ASCE Wind Loads