Skip to content
StructSuiteStructSuite
All videos

Wind Load Calculation Step by Step — MWFRS Worked Example (ASCE 7-22 Chapter 27, Directional)

2:13Published July 8, 2026Narrated, with captions and a full transcriptAlso on YouTube

Calculate the wind loads on a building's main wind-force-resisting system (MWFRS) in StructSuite per ASCE 7-22 Chapter 27, the Directional Procedure — start to finish: risk category, basic wind speed, Kd, exposure, Kzt, Ke, enclosure, the velocity pressure exposure coefficient Kz, the velocity pressure qh, external pressure coefficients Cp from Figure 27.3-1, design pressures on every surface in both wind directions, and the four design wind load cases of Figure 27.3-8.

Open the Wind Loads module
Transcript and details

About this video

What you will see

  • Choosing the procedure at Step 1: Chapter 27, the Directional method for any building shape, versus Chapter 28, the Envelope method for low-rise buildings
  • The geometry the Directional Procedure needs: plan dimension parallel to the ridge, plan dimension normal to the ridge, roof angle, and mean roof height h
  • The risk category straight from ASCE 7-22 Table 1.5-1, with all four categories I through IV on screen
  • The basic wind speed V for the site, from the ASCE hazard tool
  • The whole Step 5 parameter set in one place: wind directionality factor Kd (Table 26.6-1), exposure category (Section 26.7), topographic factor Kzt (Figure 26.8-1), ground elevation factor Ke (Table 26.9-1), and enclosure classification with the internal pressure coefficient GCpi it fixes (Table 26.13-1)
  • The velocity pressure exposure coefficient Kz read from Table 26.10-1 at every tabulated height, plus the eave, the mean roof height h and the ridge
  • Velocity pressure q = 0.00256 Kz Kzt Ke V squared (Eq. 26.10-1), using Kh at the mean roof height
  • External pressure coefficients Cp from Figure 27.3-1: windward wall, leeward wall interpolated on L/B, sidewalls, and both roof slopes interpolated on h/L and roof angle
  • Design pressures on every surface (Eq. 27.3-1), in both wind directions, with the plus and minus GCpi internal pressure cases side by side
  • The four MWFRS design wind load cases of Figure 27.3-8, required by Section 27.3.5, with the eccentricity e = 0.15B

The building in this example

120 ft parallel to the ridge by 80 ft normal to it, a 20 degree gable roof, mean roof height h = 30 ft. Risk Category II, basic wind speed V = 115 mph, Exposure C, Kd = 0.85 for an MWFRS (Table 26.6-1), Kzt = 1.0, Ke = 1.0, enclosed so GCpi = 0.18 (Table 26.13-1), and G = 0.85 for a rigid building (Section 26.11.1). At h = 30 ft in Exposure C, Table 26.10-1 gives Kh = 0.98, so qh is about 33 psf at the roof height. From Figure 27.3-1 the windward wall takes Cp = +0.8 and the sidewalls Cp = -0.7, while the leeward wall comes out at -0.40 for wind parallel to the ridge (L/B = 1.50) and -0.50 for wind normal to it (L/B = 0.67). The four Figure 27.3-8 cases carry wall-pressure factors 1.00, 0.75, 0.75 and 0.563.

Codes referenced: ASCE 7-22 Table 1.5-1; Chapter 26 — Table 26.6-1, Section 26.7, Figure 26.8-1, Table 26.9-1, Table 26.10-1, Eq. 26.10-1, Section 26.11.1 and Table 26.13-1; Chapter 27 — Figure 27.3-1, Eq. 27.3-1, Section 27.3.5 and Figure 27.3-8.

Written guides on this subject

Transcript

The narration word for word, 241 words, from the video's own captions. Select a time to play from there.

Wind Loads — ASCE 7-22 (MWFRS)

0:02In this tutorial we'll compute the wind loads on a building's main wind-force-resisting system, per ASCE 7-22.

Add the Wind Loads module

0:10From the dashboard, add the Wind Loads module. Step one: choose the procedure — Chapter 27, the Directional method for any building shape, or Chapter 28, the Envelope method for low-rise. We'll use Chapter 27.

Step 2 — building geometry

0:25Step two, geometry: a hundred-twenty by eighty-foot building, a twenty-degree gable roof, and a mean roof height of thirty feet.

Step 3 — risk category (Table 1.5-1)

0:43Step three, the risk category — pick it straight from ASCE Table 1.5-1. Ours is Risk Category Two. Step four, the basic wind speed — one hundred fifteen miles per hour, from the ASCE hazard tool for the site.

Step 5 — Kd, exposure, Kzt, Ke, enclosure

0:59Step five gathers the code parameters: the directionality factor Kd for a building, exposure category C, the topographic and ground-elevation factors — both one — and the enclosure classification, enclosed.

Step 6 — exposure coefficient Kz

1:28From there the app computes the velocity-pressure exposure coefficient, Kz, at each height — step six. Step seven gives the velocity pressure — about thirty-three pounds per square foot at the roof height.

Step 8 — external pressure coefficients

1:41Step eight brings in the external pressure coefficients from Figure 27.3-1 for each surface. Step nine delivers the design wind pressures on every surface — windward and leeward walls, sidewalls, and roof, in both wind directions.

Step 10 — design wind load cases

1:55And step ten evaluates the four MWFRS design load cases from Figure 27.3-8, combining the pressures with the required torsional effects.

Done — a full MWFRS wind calc

2:06That's a complete main-wind-force-resisting-system wind-load calculation, ready for your report.

More videos