Shearwall-steel frame lateral connection

[cheeseheadintexas]

I have a 5-story dual system building where the gravity loads are supported by steel frame, and the lateral loads are resisted by cmu shear walls. I have a question regarding the connection between these two systems, however.

I need a connection that will lateraly brace the cmu wall at each floor and transfer lateral load from the steel frame (with concrete-on-metal deck diaphragm) to the cmu shear wall, but not transfer any vertical load from the steel frame into the cmu wall. Does anyone have an idea for a detail or product that can accomodate this connection? Thanks.

 

[Taro]

First, your structure would not be considered a "dual system". A dual system uses stiff lateral elements (shear walls, braced frames) in combination with a backup system of moment-resisting frames.

The connection to the shear walls could be like a ledger angle or channel but with anchor bolts in vertically slotted holes so that the gravity load is not transferred to the wall.

 

[msquared48]

I agree with Taro.

Use a Tee section (leg vertical) with Nelson stud anchors embedded into the top of the CMU wall and a vertical fin plate welded to the bottom of the WF beam. Connecting the plates with the bolts with a vertically slotted hole system will get you where you want to go.

You could also use a channel with Nelson studs, flanges down, with a fin plate welded to the top to catch the fin plate from the WF beam as Taro suggested.

Mike McCann
McCann Engineering