WIND LOAD CALCULATION
12/02
CALCULATION OF WIND LOADS FOR BUILDINGS USING DIRECTIONAL
PROCEDURE
Determine the wind pressure for a warehouse building shown below with given
building data. Consider that the direction of the wind is in the positive x-direction.
Eave height, E= 7.5m
h’= X
Ridge height, R= X
Mean roof height, Ht= X
Location AS Fortuna, Mandaue
Terrain Urban Terrain
Occupancy Category Standard Occupancy
Wind-induced pressures on a building
Let us investigate the type of building we have..
S207: WIND LOADS
S207: WIND LOADS
S207: WIND LOADS
Category III, IV and V : Special Occupancy Structures,
a.) Basic Wind Speed, V Standard Occupancy, Miscellaneous Structures ( Table
103-1)
Design wind speed, V = X kph
Converting this, we have..
V = X m/s
S207: WIND LOADS
S207: WIND LOADS (WIND
DIRECTIONALITY FACTOR)
Kd = X
S207: WIND LOADS
S207: WIND LOADS (EXPOSURE
CATEGORY)
Exposure = Exposure X
S207: WIND LOADS (EXPOSURE
CATEGORY)
S207: WIND LOADS
S207: WIND LOADS (WIND SPEED-UP
OVER HILLS, RIDGES, & ESCARPMENTS)
S207: WIND LOADS (WIND
SPEED-UP OVER HILLS, RIDGES,
& ESCARPMENTS)
S207: WIND LOADS (WIND SPEED-UP
OVER HILLS, RIDGES, & ESCARPMENTS)
S207: WIND LOADS
(WIND SPEED-UP OVER
HILLS, RIDGES, &
ESCARPMENTS)
For Flat Terrain, Kzt = X
S207: WIND LOADS
S207: WIND LOADS (GUST EFFECT
FACTOR)
S207: WIND LOADS (GUST EFFECT
FACTOR)
S207: WIND LOADS (GUST EFFECT
FACTOR)
Assuming Rigid Structures
G=X
S207: VELOCITY PRESSURE
EXPOSURE COEFFICIENTS, KZ & KH
S207: VELOCITY PRESSURE
EXPOSURE COEFFICIENTS, KZ & KH
S207: VELOCITY PRESSURE
EXPOSURE COEFFICIENTS, KZ & KH
Calculating for velocity pressure coefficient Kz:
z = height above ground level, m
zg = constant from Table 207A.9-1
a = constant from Table 207A.9-1
2Τ𝛼
𝑧
𝐾𝑧 = 2.01 =X
𝑧𝑔
S207: VELOCITY PRESSURE
EXPOSURE COEFFICIENTS, KZ & KH
OR
Table 207B.3-1 may be used to acquire Kz.
Make sure to interpolate.
S207: VELOCITY PRESSURE
We have..
𝑞𝑧 = 0.613𝐾𝑧 𝐾𝑧𝑡 𝐾𝑑 𝑉 2
𝑞𝑧 = 0.613𝐾𝑧 𝐾𝑧𝑡 𝐾𝑑 𝑉 2
S207: VELOCITY PRESSURE
However, for the windward wall..
z (m) Kz qz (N/m2)
0-4.5 X X
6.0 X X
7.5 X X
8.82 X X
S207: WIND LOADS
S207: WIND LOADS (ENCLOSURE
CLASSIFICATION)
S207: WIND LOADS
S207: WIND LOADS (INTERNAL
PRESSURE COEFFICIENT)
Internal pressure coefficient, (GCpi) is
determined using Table 207A.11-1
For Enclosed Buildings, GCpi = X
S207: WIND LOADS (INTERNAL Let us take a look at the figures below to
understand + & - GCpi
PRESSURE COEFFICIENT)
S207: WIND LOADS (EXTERNAL
PRESSURE COEFFICIENT)
External pressure coefficient, (Cp) is determined
using the table on page 2-74
Note:
B = horizontal dimension of bldg. normal to wind
direction
L = horizontal dimension of bldg. parallel to wind
direction
h = mean roof height
θ = angle of plane of roof from horizontal
Windward Wall: Cp= X
Leeward Wall: Cp = X
Side Wall: Cp = X
S207: WIND LOADS (EXTERNAL
PRESSURE COEFFICIENT)
Windward Roof: Cp= X
Leeward Roof: Cp = X
S207: DESIGN WIND PRESSURE, P
ANSWER TO ACTIVITY
wind
ANSWER TO ACTIVITY
wind 1561
1139
1486
1395
883.7
461
808.2
716.7
ANSWER TO ACTIVITY
Pressure, Pressure,
Wall z (m) q (N/m2) G Cp qi (N/m2) GCpi
P1 (Pa) P2 (Pa)
0-4.5 1553.91 0.85 0.8 1883.38 +/- 0.18 717.65 1395.67
Windward 6.0 1687.0 0.85 0.8 1883.38 +/- 0.18 808.15 1486.17
Wall 7.5 1798.09 0.85 0.8 1883.38 +/- 0.18 883.69 1561.02
8.2 1883.38 0.85 0.8 1883.38 +/- 0.18 941.69 1619.70
Leeward 1883.38 +/- 0.18
Uniform 1883.38 0.85 -0.5 -461.43 -1139.44
Wall
Side wall Uniform 1883.38 0.85 -0.7 1883.38 +/- 0.18 -1459.62 -781.60
Windward Uniform LB 1883.38 0.85 -0.74 1883.38 +/- 0.18 -1523.35 -845.47
Roof Uniform UB 1883.38 0.85 -0.18 1883.38 +/- 0.18 -627.64 +50.89
Leeward Uniform 1883.38 0.85 -0.34 1883.38 +/- 0.18 -888.46 -209.93
