Simplified Frame Analysis - Simplified Design of Reinforced Concrete Buildings - page 27

2.2.2.2 Example: Calculation of Wind Loads - Building #1

Wind load calculations for the main wind-force resisting system of Building #1 (3-story pan joist framing) are
summarized below.

Wind-force resisting system: Beam and column framing:

(1) Wind load data

Assuming the building is classified as closed (ASCE 6.5.9) and located in hurricane prone region.

Basic wind speed V = 145 mph ASCE Figure 6-1

Occupancy category II ASCE Table 1-1

Exposure category D ASCE 6.5.6.3

Wind directionality factor K d = 0.85 ASCE Table 6-4

Importance factor I = 1 ASCE Table 6-1

Topographic factor K zt = 1 ASCE 6.5.7

Gust effect factor G = 0.85 ASCE 6.5.8

External pressure coefficient C p ASCE Figure 6-6

Windward - both directions C p = 0.8
Leeward - E-W direction (L/B = 150/90 = 1.67) C p = -0.37
N-S direction (L/B = 90/150 = 0.6) C p = -0.5

Design pressures calculations for wind in N-S direction are summarized in Table 2-3

Table 2-3 Design Pressures for N-S Direction

Height
above
ground
level, z
(ft)

Windward
design
pressure
q z GC p
(psf)

Leeward
design
pressure
q h GC p
(psf)

Total
design
pressure
(psf)

Level K z q z

(psf)

Roof 39 1.216 55.7 37.8 -23.7 61.5

2 27 1.141 51.9 35.3 -23.7 58.9

1 15 1.030 47.1 32.1 -23.7 55.7

(2) Summary of wind loads

N-S & E-W directions (conservatively use N-S wind loads in both directions):
Interior frame (30 ft bay width)

Roof = 12 kips

2nd = 23.1 kips

1st = 21.7 kips

Note: The above loads were determined using design wind pressures computed at each floor level.