ASCE 7-22 · MWFRS · WIND PRESSURE ANALYSIS
The whole-building Main Wind Force Resisting System calculator
MWFRS analysis sizes the structural backbone — frames, shear walls, diaphragms, and the full load path from roof to foundation. Run it ZIP-first.
Free to try · No signup needed for ZIP lookup
WHOLE-BUILDING SYSTEM
What an MWFRS analysis covers
The lateral system resists wind from every direction and carries it to the ground. Six things the calculator resolves for you.
Lateral force-resisting system
Moment frames, braced frames, shear walls and dual systems resisting in-plane.
FRAMES · WALLSDiaphragms & load path
Roof and floor diaphragms collect pressure and feed it to vertical elements.
CONTINUOUS PATHVelocity pressure qh
qh = 0.00256 Kz Kzt Kd Ke V², evaluated at mean roof height for the system.
qh BY HEIGHTExternal coefficients Cp / GCpf
Windward, leeward, side walls and roof — Directional Cp or Envelope GCpf.
Ch 27 / Ch 28Internal pressure GCpi
Enclosure class drives GCpi: enclosed ±0.18, partially enclosed ±0.55, open 0.00.
ENCLOSURE CLASSNet design pressures
p = q G Cp − qi(GCpi). Loads averaged over large tributary areas, not local peaks.
p = qGCp − qi GCpiTWO MWFRS PROCEDURES
Pick the right analytical procedure
ASCE 7-22 gives MWFRS two analytical paths plus wind-tunnel testing. The calculator applies the limits for you.
Directional Procedure — Chapter 27
Buildings of all heights and regular shape. Uses external pressure coefficient Cp by wall and roof surface, with G and Kd.
Cp · ALL HEIGHTSEnvelope Procedure — Chapter 28
Low-rise, simple diaphragm buildings with mean roof height ≤ 60 ft. Uses GCpf to envelope all wind directions in one pass.
GCpf · h ≤ 60 ftMWFRS, not C&C. MWFRS sizes the overall structure over large tributary areas, so pressures are area-averaged and lower than the localized peaks used for Components & Cladding. Use MWFRS pressures for the structural frame — never C&C values.
ZIP → PRESSURES → REPORT
How the MWFRS calculator works
Four steps from a ZIP code to documented design pressures.
1 · Locate the site
Enter a ZIP. ASCE 7-22 basic wind speed V is pulled for the right risk-category map.
V FROM MAP2 · Set exposure & terrain
Exposure category, Kzt for hills or escarpments, and enclosure class for GCpi.
Kz · Kzt · Ke3 · Compute pressures
qh with Kd=0.85 and G=0.85, then Cp (Ch 27) or GCpf (Ch 28) for every surface.
DIRECTIONAL / ENVELOPE4 · Export the report
Surface-by-surface pressures and load combinations, ready for permit submittal.
PERMIT-READYRUN IT ON WINDLOADCALC
Stop calculating MWFRS loads by hand
Built by structural engineers. Directional and Envelope procedures, full load path, and exportable reports — all from a ZIP code.