Locking steel floor to concrete walls in seismic zone? 3

[IJR]

Pals

I would like to rigidly connect steel girders to the top of shear walls in a highly seismic zone( peak ground acceleration 0.40g).

Theoretically I guess this is OK, provided I analyse both together and as close to reality as is possible, proportion them accordingly and check some temperature effects too(not significant since floor is insulated and is inside the building).

I will appreciate your final opinion before I make my dive.

respects
ijr

 

[JedClampett]

You might want to consider the details to this. You have a concrete wall with reasonable construction tolerances and you're expecting to fit a steel beam in a specified gap. Plus, contractors have a difficult time lowering a steel member exactly horizontal. And what is the advantage of a rigid member as opposed to a pinned one?
You have to make your model matches the design, but you also have to make sure the design is constructable.

 

[ishvaaag]

1st I would look if definitely can be assorted to one of the lateral systems allowed to be practiced at the zone; I assume it can. Then at 0.4g at ground, connections to the top of the shearwalls at the supports of main beams taking the loads are going to see important forces and will be something requiring good detailing and so need be object of the utmost care. For just adhesion at the interface is not going to be enough and a nice set of anchors to concrete is foreseeable will appear; quite likely welding the rebar itself to the receiving plates may appear as something convenient or even necessary, even if maybe too much indeterminate for the taste of anyone accustomed to use the most precise numbers.

 

[InDepth]

IJR, just a quick clarification:

What do you mean by "rigidly connect steel giders to shear walls"? Are you trying to make a moment connection or connect shear walls with a steel coupling beam? Or are you trying to drag seismic forces through a steel beam into the shear wall? Are the girders perpendicular or parallel to the shear wall?.....i.e. what is your intent?

What is your roof diapgrahm? Concrete fill or plain metal deck?

 

[msquared48]

Also, are the beams normal to or parallel to the wall?

Mike McCann
MMC Engineering

 

[IJR]

InDepth and msquared48

By rigidly connecting I meant no sliding. Connection may rotate but no translation.

Walls are simply continuous suppports to my array of beams, I mean shear walls are at the periphery of the floor.

Floor is lightweight concrete deck, but I am not going to rely on the deck for diaphragm action, I am going to heavily brace the floor.

And as ishvaag noted, I am going to anchor the beams with a large factor of safety.

respects
ijr