Wind Loads on Main Wind Force Resisting System and Components & Cladding


MWFRS (Main Wind Force Resisting System) loads are the pressures you use to design the overall structural system that keeps the building standing and stable: primary frames, braced bays, shear walls, diaphragms/collectors, and the load path to the foundation. The goal is to capture overall forces and moments (base shear, overturning, torsion, overall uplift) on the building as a whole. ASCE 7-22 provides MWFRS procedures mainly in Chapter 27 (Directional Procedure) and Chapter 28 (Envelope Procedure, typically for low-rise buildings). 

Components & Cladding loads are for individual elements and their attachments that form the building envelope (roof panels, wall panels, copings/edge metal, doors/windows, and often purlins/girts and their connections depending on what they support). These elements “feel” highly localized peak suctions/pressures, especially at corners and edges, so ASCE 7-22 uses Chapter 30 with zone-based coefficients and effective wind area (EWA) effects (small areas generally attract higher coefficients/pressures because peak gust effects don’t average out).

By separating MWFRS and C&C in the model and in the generated load cases, MkaPEB avoids a common practical mistake: using global pressures to design local envelope components, or using local peak pressures to size the entire primary system—both of which can lead to inefficient or unsafe designs.


Wind Loads on Main Wind Force Resisting System

In MkaPEB, wind loads for the Main Wind Force Resisting System (MWFRS) of low-rise buildings are determined using the Envelope Procedure in ASCE 7-22, Chapter 28 (Wind Loads on Buildings: MWFRS (Envelope Procedure)). The calculation accounts for key parameters including the building risk category, basic wind speed, wind directionality factor, exposure category, topographic factor, ground elevation factor, enclosure classification, and the internal pressure coefficient.




Wind Loads on Components & Cladding

In MkaPEB, wind pressures for Components and Cladding (C&C) are determined in accordance with ASCE 7-22, Chapter 30 (Wind Loads: Components and Cladding). The calculation accounts for key parameters including the building risk category, basic wind speed, wind directionality factor, exposure category, topographic factor, ground elevation factor, enclosure classification, and the internal pressure coefficient.




References:

[1] American Society of Civil Engineers. "Minimum design loads and associated criteria for buildings and other structures." American Society of Civil Engineers, 2022.