Seismic Force When Designing Shear Friction

[calvinhCA]

Found out this is the only forum where structural engineers are active.

Here is the one-story CMU wall structure. The base shear is always being considered as summing up the roof weight + upper half of the wall weight. When it comes to design the adequate of the shear friction between the bottom of the shear wall and the top of the foundation, do you still use the same base shear for the shear friction demand, or you will add the lower half of the wall weight on top of the base shear?

 

[KootK]

or you will add the lower half of the wall weight on top of the base shear?

I'd not thought of this previously but I think that you're right, the inertial load of the bottom half of the wall has to go somewhere.

 

[calvinhCA]

In my previous design, the shear friction check was frequently ignored, but in reality, it is a construction joint. Recently I was doing some light reinforcement work and start thinking about it. Glad you also agree on it.

 

[TRAK.Structural]

As @KootK mentioned, all of the shear has to be considered when checking the connection of the superstructure to the foundation elements (and for global sliding, overturning, etc.) Mass from the lower half of walls should be resisted at the base of the contributing wall though, not distributed by the roof diaphragm.

I've always considered "Base Shear" to be the total shear including the lower half of walls, just a terminology thing though.