Special Deflection Requirements for OWSJ Parallel to Non-flexible members

[cameron737]

I am looking for some insight into special deflections of Joists parallel to a non-flexible member, like a masonry wall. I’ve found in Canam’s catalogue something talking about modifying the deflection of the first 2-3 joist in from the wall ie. 1st joist L/500, 2nd joist L/300, 3rd joist L/280 (general deflection = L/240). I have seen in many structural drawgings the 1st joist @ L/720, and the 2nd @ L/600. Sometimes there's a 3rd, sometimes not.

Is there something in S16 or S136 that deal with this? Any help is appreicated. We are trying to develop a standard, but I am not having any luck finding where its defined.

 

[MiketheEngineer]

I believe this is an engineering decision. I have had similar problems with steel basement beams that end abruptly allowing an adjacent joist to deflect more.

While I cannot say your ideas are correct - they do seem reasonable....

 

[Ron]

This was recently discussed in the structural forum (general). Check there and search.

 

[msquared48]

I do this all the time in wood framing, around any hard point, to minimize working of the diaphragm, and graduate the deflection difference. Makes for a happier client.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com