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Expansion joint detail parallel to joist span

Expansion joint detail parallel to joist span

Expansion joint detail parallel to joist span

(OP)
I have an expansion joint in my metal deck that runs parallel with the bar joist.  I need to transfer a shear load across this joint.  Does anyone have suggestions on how this is done?  Diagonal brace across joint?  What happens at my chord members at this joint? Thank you   

RE: Expansion joint detail parallel to joist span

Cont. plate welded to one side and the other side bolts in slots. Arrange slots to allow movement in one direction, and transfer shear in other.

RE: Expansion joint detail parallel to joist span

Chords are discontinuous across joint. You esentially have two 3 sided boxes, with open ends facing each other.  

RE: Expansion joint detail parallel to joist span

(OP)
jike-
Can you assume a 3 sided box?  Don't I have a flexible diaphragm?

RE: Expansion joint detail parallel to joist span

You need to make the diaphragm so that it works as a 3 sided box.

RE: Expansion joint detail parallel to joist span

(OP)
jike,
I understand what you are doing.  I've done this myself.  But being a flexible building can we really do this?    Technically this is a flexible diaphragm and this isn't suppose to be done.  Tributary areas are suppose to be used not torsional resistance.  Like I say, I've done it but don't know if it works in this case because I have a long slender building.  Let me know what you think.

RE: Expansion joint detail parallel to joist span

The diaphragm classification has to do with its deflection relative to the interstory drift. For metal deck diaphragms, it is permitted to be idealized as flexible but that does not mean that all metal deck diaphragms are flexible especially if they are approximately square, are heavier than normal or have supplemental horizontal bracing.

I would only attempt what I am describing with an approximately square diaphragm. If you have a long narrow building, you should use rigid frames or some other type of bracing system and not attempt to transfer very much shear across the joint.

RE: Expansion joint detail parallel to joist span

(OP)
jike-
Yes, agree totally with what you are saying.  I'm definitely dealing with a flexible diaphragm.  My structure is about 100'x400'. I was going to provide a expansion joint in the center and treated as a simple 400' beam. I was going to put my expansion the middle of the building where there is zero shear.  But at the location is my largest moment.  So I need to have a continuous chord at that location. Can that go through my expansion joint? Maybe I'm barking up the wrong tree and should just analyize 2 seperate diaphragms.   

RE: Expansion joint detail parallel to joist span

Is this a 1 story, steel framed building?

If so, you may not need an expansion joint. 400' without an expansion joint is 'do able' in a single story, steel framed building.  

RE: Expansion joint detail parallel to joist span

(OP)
lkjh345- It is one story but and the exterior walls are cmu walls.  The structure is actually L shaped.  With a square building I would agree but with an L like I have I'm not real sure.

RE: Expansion joint detail parallel to joist span

I do not know how you can make the chords continuous but yet have a fully functional expansion joint.  

Go with 2 separate diaphragms!

 

RE: Expansion joint detail parallel to joist span

(OP)
jike-
Thats not the answer I wanted!!!  Erase your last post and tell me something different. I suspected thats what I was going to hear but I just didn't couldn't accept it.  Thanks

RE: Expansion joint detail parallel to joist span

Make sure your diaphragm does not deflect too much if you have CMU walls!

RE: Expansion joint detail parallel to joist span

ars13,

Take jike's advice.  You can't have it both ways.

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