Wind Load on Walls for Open Structures

[tmgczb]

In ASCE, open structures are defined as those structures with opening area more than 80% of total area for windward wall. Here we know that there is 20% area left for walls. But wind pressure coefficients Cp are not clear for walls on open structures.

 

[StrEng007]

The Cp factor for use with MWFRS wind loads would not be applicable. If the building is open, there aren't enough walls to obstruct the wind and build up any internal pressure on the structure. Regarding MWFRS pressures, you're left with wind loads on the roof per ASCE 7-16, Section 27.3.2. Depending on the roof pitch, there is a horizontal component to the wind load applied normal to the roof framing. Keep in mind that Chapter 27 is provided for the MWFRS of the overall structure, not just the out of plane check for a section of wall.

Additionally, the provisions of Chapter 30 also don't apply for completely vertical wall surfaces. Again, this chapter will provide guidance for C&C wind applied to the roof framing members.

To check the design of a vertical surface with no internal pressure, you could refer to Chapter 29, Section 29.3.1.