Masonry Wind Column. Not Seismic.

[EIT2]

In the design of a Carport Canopy, the 14' concrete masonry columns will be designed to resist a 9k lateral wind load at top. The bases will be spliced/doweled to concrete pier and footing.

I have two, excellent, working stress, design examples to follow, for combined bending and direct stresses, resisting a seimic moment.

Can these same examples also be used to resist a lateral wind load?

Thank you!

 

[Taro]

Yes

 

[JAE]

Yes (I'm a copycat)

 

[jheidt2543]

EIT2,

I guess the way I would ask the question is, if I have a horizontal load Ph, does the structure I am designing know if it is a wind load or a seismic load. I think what Taro and JAE are saying is NO and I agree.

The difference between a wind load and a seismic load is how you arrive at the size of Ph.

 

[EIT2]

jheidt2543, Taro and JAE,

The way I arrive at Ph for wind is the simple tributary procedure. Fortunate for myself, designing for the north and central Wisconsin region, I seldom recognize seimic forces. I have great respect for those who do.

My reason for inquiry is this:

My column bases are fixed to the concrete. The column caps are free with the steel beams, which support the canopy roof trusses, bolted to the top. Wind forces act on the free end. Seismic forces would act on the fixed end base. Does this change the design and/or any of your replies?

I apologize if I was not clear on the end conditions.

Thank you.

 

[Taro]

No difference in the fundamental design approach. The forces result from differential movement of the ends of the member. It does not matter whether that differential movement is caused by wind pressure or by earthquake inertial forces.

 

[JAE]

For Wisconsin - you would be using the static design approach for seismic which is modeled as a load applied at the center of mass. While the actual load "path" of a seismic event is due to ground accelleration, the design forces, shears and moments all behave as thought the load path were down through the columns from the mass of the roof overhead....similar to the wind.

With the ASD approach, be sure to use the required code load combinations - for the IBC 2000 code, the seismic loads you calculate should be reduced - E/1.4 to get to a working stress level.