V. ASCE 7-22 Wind Load Generation on Building

Validate STAAD.Pro calculated equivalent joint loads for a closed structure subjected to wind loading as per ASCE 07–22.

References

American Society of Civil Engineers and Structural Engineering Institute. ASCE 7: Minimum Design Loads and Associated Criteria for Buildings and Other Structures. 2022. American Society of Civil Engineers.

Details

The wind load is calculated for a building structure using the direction procedure for MWFRS of enclosed buildings (ASCE 7-22, Chapter 27). The following assumptions and parameters apply:

  • Flat roof type
  • Category II building (Table 1.5-1 of ASCE 7-22)
  • Basic wind speed = 108 mph
  • Ground height above sea level = 300 ft
  • Structure type of “building”
  • Exposure Category B
  • Do not consider wind speed-up over hills or escarpments
  • Building height, h = 20 ft
  • Building length along the wind direction, L = 10 ft
  • Building width normal to wind direction, B = 20 ft
  • Natural frequency of structure = 2 Hz (i.e., a “rigid” building per Cl. 26.2 of ASCE 7-22)
  • Enclosed building

Calculations

Validation

Topographic factor, Kzt = 1.0

Ground elevation factor, Ke = e-0.0000362×300 = 0.989 (Table 26.9-1, note 2)

The velocity pressure coefficent, Kz, is calculated as:

(Table 26.10-1)

where

ɑ
=
3-s gust-speed power law exponent = 7.5
zg
=
Nominal height of the atmospheric boundary layer = 3,280 ft

See the table below for the values of Kz at discrete values of z.

Velocity pressure, qz

(26.10-1)

Mean roof height = height of the building = 20 ft. Refer to table below for calculation of qz at the mean roof height.

Gust effect factor, G

G is calculated per Cl. 26.11.4 for rigid structures:

(26.11-6)

where

gq = gv
=
3.4
=
equivelant height of structure (Table 26.11-1)
ε
=
ratio of solid area to gross area = 1/3.0 (Table 26.11-1)
ℓ
=
integral length scale factor = 320 ft (Table 26.11-1)
c
=
turbulence intensity factor = 0.3 (Table 26.11-1)
=
Q
=
background response factor,
=
intensity of turbulence,

Therefore,

The external design pressure,

(27.3-1)

where

Kd
=
directionality factor for MWFRS (Table 26.6-1), Kd = 0.85
Cp
=
wall pressure coefficient for windward per Fig. 27.3-1, Cp = 0.8
GCpi
=
The internal pressure coefficient for partially enclosed buildings per Table 26.13-1, GCpi = -0.18
qi
=
the velocity pressure evaluated at the building height, h, = qh
Table 2. Wind intensity versus height for building structure
Height

(ft)

 Velocity pressure coefficient, Kz Velocity pressure, qz

(lb/ft2)

 Design wind pressure, p

(lb/ft2)
≤ 15 0.573 16.92 12.92
15.5 0.578 17.07 13.01
16.5 0.588 17.36 13.18
17.5 0.597 17.63 13.35
18.5 0.606 17.90 13.50
19.5 0.614 18.15 13.66
20 0.619 18.27 13.73

Nodes 1 and 9 - edge supports

Tributary area of these nodes: 10'/2 × 10'/2 = 25 ft2

Force: Fw = p×A = 12.92 × 25 (10)-3 = 0.323 kips

Node 5 - center supports

Tributary area of these nodes: 10'/2 × 10' = 50 ft2

Force: Fw = p×A = 12.92 × 50 (10)-3 = 0.646 kips

Node 2 and 10 - mid-height at edges of building

Tributary area of these nodes: 10' × 10'/2 = 50 ft2

Force: Fw = p×A = 12.92 × 50 (10)-3 = 0.646 kips

Node 6 - center node of building

Tributary area of these nodes: 10' × 10' = 100 ft2

Force: Fw = p×A = 12.92 × 100 (10)-3 = 1.292 kips

Nodes 13 and 17 - corners at top of building

Pressure varies with height along this section, width is 10'/2 = 5 ft. Use average pressure in 1' increments.

h (ft) pavg (lb/ft2) F (lbs)
15.5 13.01 65.1
16.5 13.18 65.9
17.5 13.35 66.7
18.5 13.50 67.5
19.5 13.66 68.3
∑ = 333.5 = 0.334 kips

Node 15 - center at top of building

Pressure varies with height along this section, width is 10 ft. Use average pressure in 1' increments.

h (ft) pavg (lb/ft2) F (lbs)
15.5 13.01 130.1
16.5 13.18 131.8
17.5 13.35 133.5
18.5 13.50 135.0
19.5 13.66 136.6
∑ = 667.0 = 0.667 kips

Results

Table 3. Joint loads due to wind (kips)
Result Type Reference STAAD.Pro Difference Comments
Node 1 0.323 0.32 negligible
Node 2 0.646 0.65 negligible
Node 5 0.646 0.65 negligible
Node 6 1.292 1.29 negligible
Node 9 0.323 0.32 negligible
Node 10 0.646 0.65 negligible
Node 13 0.334 0.33 negligible
Node 15 0.667 0.67 negligible
Node 17 0.334 0.33 negligible

Input

The file C:\Users\Public\Public Documents\STAAD.Pro 2026\Samples \Verification Models\06 Loading\Wind Load\ASCE 7-22 Wind Load Generation on Building.STD is typically installed with the program.

STAAD

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 21-Jun-25
END JOB INFORMATION
*****************************************************************
*This problem has been created to verify the program calculated
*intensities of wind pressure as per ASCE 07-2022 and
*verify equivalent joint loads in the joints of a
*closed structure subjected to wind
*****************************************************************
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 0 10 0; 3 10 10 0; 4 10 0 0; 5 0 0 10; 6 0 10 10; 7 10 10 10;
8 10 0 10; 9 0 0 20; 10 0 10 20; 11 10 10 20; 12 10 0 20; 13 0 20 0;
14 10 20 0; 15 0 20 10; 16 10 20 10; 17 0 20 20; 18 10 20 20;
MEMBER INCIDENCES
1 1 2; 2 2 3; 3 3 4; 4 2 6; 5 3 7; 6 5 6; 7 6 7; 8 7 8; 9 6 10; 10 7 11;
11 9 10; 12 10 11; 13 11 12; 14 2 13; 15 3 14; 16 6 15; 17 7 16; 18 10 17;
19 11 18; 20 13 14; 21 13 15; 22 14 16; 23 15 16; 24 15 17; 25 16 18; 26 17 18;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+06
POISSON 0.3
DENSITY 0.489024
ALPHA 6.5e-06
DAMP 0.03
G 1.6128e+06
TYPE STEEL
STRENGTH RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY 'US (AISC V16.0).DB3'
1 TO 26 TABLE 'W' ST 'W14X873'
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 4 5 8 9 12 FIXED
DEFINE WIND LOAD
TYPE 1 WIND 1
<! STAAD PRO GENERATED DATA DO NOT MODIFY !!!
ASCE-7-2022:PARAMS 108.000 mph 300.000 ft 0 1 1 0 0.000 ft 0.000 ft 0.000 ft -
1 3 20.000 ft 10.000 ft 20.000 ft 2.000 0.050 0 0 0 0 0 0 0.619 1.000 1.000 -
0.989 0.000 0 0 0 0 0 0.880 0.800 -0.180 0.850
!> END GENERATED DATA BLOCK
INT 0.01292 0.01292 0.01299 0.01305 0.01312 0.01318 0.01325 0.01331 0.01337 -
0.01343 0.01349 0.01355 0.01361 0.01367 0.01372 HEIG 0 15 15.385 15.769 -
16.154 16.538 16.923 17.308 17.692 18.077 18.462 18.846 19.231 19.615 20
LOAD 1 LOADTYPE Wind  TITLE LOAD CASE 1
WIND LOAD X 1 TYPE 1
PERFORM ANALYSIS PRINT LOAD DATA
FINISH

Output

   LOADING     1  LOADTYPE WIND  TITLE LOAD CASE 1                            
   -----------


   JOINT LOAD - UNIT KIP  FEET

   JOINT   FORCE-X   FORCE-Y     FORCE-Z     MOM-X     MOM-Y     MOM-Z

       1      0.32      0.00        0.00      0.00      0.00      0.00
       2      0.65      0.00        0.00      0.00      0.00      0.00
       5      0.65      0.00        0.00      0.00      0.00      0.00
       6      1.29      0.00        0.00      0.00      0.00      0.00
       9      0.32      0.00        0.00      0.00      0.00      0.00
      10      0.65      0.00        0.00      0.00      0.00      0.00
      13      0.33      0.00        0.00      0.00      0.00      0.00
      15      0.67      0.00        0.00      0.00      0.00      0.00
      17      0.33      0.00        0.00      0.00      0.00      0.00