Expansion joint detail parallel to joist span

[ars13]

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

 

[jike]

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.

 

[jike]

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

 

[ars13]

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

 

[jike]

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

 

[ars13]

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.

 

[jike]

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.

 

[ars13]

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.

 

[lkjh345]

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.

 

[ars13]

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.

 

[jike]

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

Go with 2 separate diaphragms!

 

[ars13]

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

 

[jike]

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

 

[hokie66]

ars13,

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