why is sidewall pressure ignored in MWFRS wind?

[delagina]

for global MWFRS wind analysis, why is sidewall pressure ignored per fig 6-6 of ASCE?

they may cancel out but the effect is there specially for isolated foundation?

 

[msquared48]

You look at the structure from a minimum of two global directions. Sidewall pressures are local, and orthogonal to the main pressure direction under consideration.

Mike McCann
MMC Engineering

 

[asixth]

They'll place more horizontal thrust on the foundations and may increase the design actions in the bracing (tension), so they should be included but globally they cancel out like you said.

 

[Lion06]

I think any additional load placed on a foundation from sidewall pressure, when compared to the wind in the primary direction, is nominal, at best, and rightfully neglected.

I might be able to see the point for a system that has wind girts framing into the columns instead of a facade spanning from foundation to floor and then between floors.

 

[hokie66]

For portal frames, I don't know why you wouldn't include the side wall pressure in the parallel to ridge case. The opening moment at the hip is increased by the sidewall pressure, at least for buildings where girts span to the columns.

 

[Ron]

Wasn't this just discussed a few weeks ago?

 

[abusementpark]

It should definitely be considered for longitudinal wind on a pre-engineering metal building frame.

 

[hokie66]

abusementpark,
Why the distinction between pre-engineered and otherwise? The wind doesn't know the difference.