Should I use MWFRS or C&C wind load for designing foundations of a building

[structguy777]

I am designing shallow foundations only for a building - which has no columns - it has channels at the bottom and cladding all around. The channels at the bottom will sit directly on the shallow foundations. Should I use MWFRS or C&C wind load to get the reactions at the bottom? I think I should use C&C wind load. Please confirm.

 

[JAE]

What is your tributary area affecting the footings? Typically if it is more than 700 s.f. I use MWFRS.

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[manstrom]

MWFRS for the foundation. C&C if it was a single component with little redundancy.

When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller

 

[structguy777]

@JAE - There are 14 shallow foundations supporting the entire building. Largest tributary are for a footing is 213 SF. Can you please tell me from where did you get 700 SF as criteria for using MWFRS?

@manstrom - There are 14 shallow foundations supporting the entire building. Why should I use MWFRS?

Should I use C&C for the roof?

 

[manstrom]

If they are a part of the Main Wind Force Resisting System, and are resisting the overturning / sliding of the entire building globally, then I would use MWF.

Use whatever you want.

When I am working on a problem, I never think about beauty but when I have finished, if the solution is not beautiful, I know it is wrong.

-R. Buckminster Fuller

 

[Jerehmy]

ASCE 7-10 30.2.3 Tributary Areas Greater than 700 ft2 (65 m2) -- Component and cladding elements with tributary
areas greater than 700 ft2 (65 m2) shall be permitted to be designed using the provisions for MWFRS.

 

[SKJ25POL]

structguy777 (Structural), can you rovide a pic or sketch of building so I can tell you what to use

A 3D sketch or pic or freehand sketch will help visualize your case

 

[JAE]

Thanks, Jerehmy for looking that up.

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[abusementpark]

A lot of engineers argue foundations are always MWFRS regardless of tributary area.

 

[mike20793]

I agree with abusementpark. The foundations are neither cladding or a component that delivers wind load to the lateral force resisting system, so they should be designed for MWFRS.