precast wall panel and steel frame 1

[bjb]

We have an addition to design where the proposed construction is a steel frame with precast concrete wall panels. We don't often design this type of building, and I have a few question:

We are considering erecting a steel frame, and then having non-load bearing wall panels for the exterior. We would use the wall panels for shear walls only. Because it is an addition, there will only be shear walls on 3 sides, and the roof diaphragm will be steel wide rib deck. Does this sound reasonable? The building is in a low-seismic area.

 

[astructurale]

I have seen this type of structure before, so it is not uncommon. Sometimes braced frames are in the 4th side, or the precast wall system is designed 3 sided. You'll need to account for the eccentricity created from the center of rigidity being far from the center of the lateral load. You should design and detail the steel wide rib deck for this diaphragm torsion created by the eccentricity. If you look on page 3-33 of the 6th Edition of the PCI Design Handbook it has an example structure very similar to the one that you describe.

Another way to go is to design an expansion joint between the old and new, and design your connections to transfer the shear, but allow for movement at the expansion joint. However, that detailing may prove to be to cumbersome and difficult to control and or install.

 

[bjb]

thanks for your response