Multi-story Tilt up building - SFRS

[strucguy]

I am working on a 4-story tilt-up office building. I know that for seismic design, the tilt wall system can be rationalized as being a bearing wall system or concrete moment frame resisting system. Now my question is, is there any criteria in the code that let's you choose one system over the other for the seismic design. Here's more information.

14 ft floor to floor height
panel width is 30 ft
the panel has two openings (9.5 ft x 10 ft) at each level.

From my research I found that with openings this big, the panels are best analyzed as being concrete moment frames. But, my colleague thinks otherwise. Any comments? Thanks in advance.

 

[msquared48]

Seems like you are dealing with two four foot end panel columns and a central two foot wide column at each panel. The top girder appears to be in the order of four feet too.

Regardless of the openings, this seems like a lot of concrete shear wall length and girder depth to be modeled like a moment frame, especially with the steel required here. I think that I would lean more to the bearing wall analysis, using the PCA thin wall load bearing wall method.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[vandede427]

They're not moment frames. They're perforated shear walls.

For seismic R, use the Bearing Wall - Precast category.