Wind
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Wind EXHAUST STACK ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers A B C D E F G H I J K L WIND '97 UBC V_basic 36 mph Exposure B 2 Exposure and gust factor coefficient B or C 16-G I 1 unitless importance factor 16-K 0.80 unitless pressure coefficient from Table 16-H h_slab 2.00 ft from grade to foundation interface to top of foundation Speed mph 70.0 80.0 90.0 100.0 110.0 120.0 130.0 150.0 175.0 basic wind speed 12.6 16.4 20.8 25.6 31.0 36.9 43.3 57.6 78.4 3.3 psf wind stagnation pressure, std ht 33', 16-G 16-K OCCUPANCY CATEGORY I_E I_Ep I_Wind 1. ESSENTIAL FACILITIES 1.25 1.5 1.15 2. HAZARDOUS FACILITIES 1.25 1.5 1.15 3. SPECIAL OCCUPANCY 1.0 1.0 1.0 4. STANDARD OCCUPANCY 1.0 1.0 1.0 5. GROUP U 1.0 1.0 1.0 Hydrogen, oxygen, nitrogen, and carbon dioxide all qualify as hazardous materials. This requires a higher importance factor. 16-H Cq PRESSURE COEFFICIENTS Chimneys, tanks, solid towers Square or Rectangul 1.4 Hexagonal or octagona 1.1 Round or elliptical 0.8 16-G Ce COMBINED HEIGHT, EXPOSURE, and GUST FACTOR COEFFICIENT HEIGHT Exp_D Exp_C Exp_B 400 2.34 2.19 1.80 6.0 4.8 300 2.23 2.05 1.63 5.4 4.3 200 2.10 1.87 1.42 4.7 3.8 160 2.02 1.79 1.31 4.4 3.5 120 1.93 1.67 1.20 4.0 3.2 100 1.88 1.61 1.13 3.8 3.0 80 1.81 1.53 1.04 3.5 2.8 60 1.73 1.43 0.95 3.2 2.5 40 1.62 1.31 0.84 2.8 2.2 30 1.54 1.23 0.76 2.5 2.0 25 1.50 1.19 0.72 2.4 1.9 20 1.45 1.13 0.67 2.2 1.8 15 1.39 1.06 0.62 2.1 1.7 top of foundation anchor bolt interface bottom of foundation soil/foundation interface basic wind speed per customer specifications Cq P = Ce * Cq * qs * I 16-F qs WIND STAGNATION PRESSURE at STANDARD HEIGHT of 33' qs psf 0.00256 * basic_ qs w/o Cq with Cq
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Page 21 - 1
document.xls
WindEXHAUST STACK
ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers
A B C D E F G H I J K L M
21
WIND '97 UBCV_basic 36 mphExposure B 2 Exposure and gust factor coefficient B or C 16-GI 1 unitless importance factor 16-K
0.80 unitless pressure coefficient from Table 16-H
h_slab 2.00 ft from grade to foundation interface to top of foundation
Speed mph 70.0 80.0 90.0 100.0 110.0 120.0 130.0 150.0 175.0 basic wind speed
12.6 16.4 20.8 25.6 31.0 36.9 43.3 57.6 78.4
3.3 psf wind stagnation pressure, std ht 33', 16-G
16-K OCCUPANCY CATEGORYI_E I_Ep I_Wind
1. ESSENTIAL FACILITIES 1.25 1.5 1.152. HAZARDOUS FACILITIES 1.25 1.5 1.153. SPECIAL OCCUPANCY 1.0 1.0 1.04. STANDARD OCCUPANCY 1.0 1.0 1.05. GROUP U 1.0 1.0 1.0Hydrogen, oxygen, nitrogen, and carbon dioxide allqualify as hazardous materials. This requires ahigher importance factor.
16-H Cq PRESSURE COEFFICIENTSChimneys, tanks, solid towersSquare or Rectangular 1.4Hexagonal or octagonal 1.1Round or elliptical 0.8
16-G Ce COMBINED HEIGHT, EXPOSURE, andGUST FACTOR COEFFICIENT
HEIGHT Exp_D Exp_C Exp_B
400 2.34 2.19 1.80 6.0 4.8300 2.23 2.05 1.63 5.4 4.3200 2.10 1.87 1.42 4.7 3.8160 2.02 1.79 1.31 4.4 3.5120 1.93 1.67 1.20 4.0 3.2100 1.88 1.61 1.13 3.8 3.080 1.81 1.53 1.04 3.5 2.860 1.73 1.43 0.95 3.2 2.540 1.62 1.31 0.84 2.8 2.230 1.54 1.23 0.76 2.5 2.025 1.50 1.19 0.72 2.4 1.920 1.45 1.13 0.67 2.2 1.815 1.39 1.06 0.62 2.1 1.7
top of foundationanchor bolt interface
bottom of foundationsoil/foundation interface
basic wind speed per customer specifications
Cq
P = Ce * Cq * qs * I
16-F qs WIND STAGNATION PRESSURE at STANDARD HEIGHT of 33'
qs psf 0.00256 * basic_wind_speed2 mph
qs
w/o Cq with Cq
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WindEXHAUST STACK
ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers
A B C D E F G H I J K L M
21
Figure 21-1 Graduated wind force acting on a structure.
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WindEXHAUST STACK
ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers
A B C D E F G H I J K L M
21
WIND OVERTURNING -- INCREMENTAL MOMENTSHeights are taken from the top of the footing
ABOUT X-Axis ↑ To the TOP of the footing ↑ To the BOTTOM of the footing ↑ht 1 ht 2 width force arm Mot arm Mot
HEIGHT q psf from bot to top along X about x about x about x about x about x400 4.8 300 400 0 0.00 350.00 0.0 352.00 0.0300 4.3 200 300 0 0.00 250.00 0.0 252.00 0.0200 3.8 160 200 0 0.00 180.00 0.0 182.00 0.0160 3.5 120 160 0 0.00 140.00 0.0 142.00 0.0120 3.2 100 120 0 0.00 110.00 0.0 112.00 0.0100 3.0 80 100 0 0.00 90.00 0.0 92.00 0.080 2.8 60 80 3.5 0.19 70.00 13.6 72.00 14.060 2.5 40 60 3.5 0.18 50.00 8.9 52.00 9.240 2.2 30 40 3.5 0.08 35.00 2.7 37.00 2.930 2.0 25 30 3.5 0.04 27.50 1.0 29.50 1.025 1.9 20 25 3.5 0.03 22.50 0.8 24.50 0.820 1.8 15 20 3.5 0.03 17.50 0.5 19.50 0.615 1.7 0 15 3.5 0.09 7.50 0.7 9.50 0.8
0.64 k 28.1 k-ft top1376.00 29.4 k-ft bottom
ABOUT Y-Axis → To the TOP of the footing → To the BOTTOM of the footing →ht 1 ht 2 width force arm Mot arm Mot
HEIGHT q psf from bot to top along X about x about x about x about x about x400 4.8 300 400 0 0.00 350.00 0.0 352.00 0.0300 4.3 200 300 0 0.00 250.00 0.0 252.00 0.0200 3.8 160 200 0 0.00 180.00 0.0 182.00 0.0160 3.5 120 160 0 0.00 140.00 0.0 142.00 0.0120 3.2 100 120 0 0.00 110.00 0.0 112.00 0.0100 3.0 80 100 0 0.00 90.00 0.0 92.00 0.080 2.8 60 80 3.5 0.19 70.00 13.6 72.00 14.060 2.5 40 60 3.5 0.18 50.00 8.9 52.00 9.240 2.2 30 40 3.5 0.08 35.00 2.7 37.00 2.930 2.0 25 30 3.5 0.04 27.50 1.0 29.50 1.025 1.9 20 25 3.5 0.03 22.50 0.8 24.50 0.820 1.8 15 20 3.5 0.03 17.50 0.5 19.50 0.615 1.7 0 15 3.5 0.09 7.50 0.7 9.50 0.8
0.64 k 28.1 k-ft top1376.00 29.4 k-ft bottom
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WindEXHAUST STACK
ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers
A B C D E F G H I J K L M
21
Figure 21-2 FOUNDATION SIGNS
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WindEXHAUST STACK
ENGINEERING with the SPREADSHEET Copyright 2006 American Society of Civil Engineers
A B C D E F G H I J K L M
21
VERIFICATION OF TABLE VALUES
smooth line and if these values can generate a formula.
Published Table Values
HEIGHT Exp_D Exp_C Exp_B400 2.34 2.19 1.80300 2.23 2.05 1.63200 2.10 1.87 1.42160 2.02 1.79 1.31120 1.93 1.67 1.20100 1.88 1.61 1.13
80 1.81 1.53 1.0460 1.73 1.43 0.9540 1.62 1.31 0.8430 1.54 1.23 0.7625 1.50 1.19 0.7220 1.45 1.13 0.6715 1.39 1.06 0.62
Figure 21-3 TABLE VALUES
Calculation: Wind Pressure versus Velocity Gust Factor Coefficient
V 35.6 mph pressure coefficient
P wind 3.3 V wind velocity of wind, miles/hourP wind pressure of wind, Lbs./ft²
wind stagnation pressure at standard height
wind pressure at a designated height, Lbs./ft²
I importance factor
V_basic basic wind speed, miles/hourExposure Exposure and gust factor coefficient B, C, or D
Determine if published coefficients of Ce create a
Gust Factor Coefficient Ce
Ce
Cq
lb/ft2 0.00257 * (V miles/hour)2
Qs
qs
0 50 100 150 200 250 300 350 400 450
0.00
0.50
1.00
1.50
2.00
2.50
f(x) = 0.251970268713529 x^0.326243409029644R² = 0.999463795394243
f(x) = 0.582380161901318 x^0.220580496884977R² = 0.999847398396087
f(x) = 0.898736071472569 x^0.159711238147259R² = 0.999833148112723
Column B
Power (Column B)
Power (Column B)
Column C
Power (Column C)
Column D
Power (Column D)
HEIGHT
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0.00256 * basic_wind_speed2 mph
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To the BOTTOM of the footing ↑
row 80
row 90k-ft bottom
To the BOTTOM of the footing →
row 100
row 110
k-ft bottom
row 120
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#REF!
#REF!
row 143
row 170
wind stagnation pressure at standard height
wind pressure at a designated height, Lbs./ft²
Exposure and gust factor coefficient B, C, or D
row 180
0 50 100 150 200 250 300 350 400 450
0.00
0.50
1.00
1.50
2.00
2.50
f(x) = 0.251970268713529 x^0.326243409029644R² = 0.999463795394243
f(x) = 0.582380161901318 x^0.220580496884977R² = 0.999847398396087
f(x) = 0.898736071472569 x^0.159711238147259R² = 0.999833148112723
Column B
Power (Column B)
Power (Column B)
Column C
Power (Column C)
Column D
Power (Column D)
HEIGHT
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