Diaphragm Chord Forces
Diaphragm Chord Forces
(OP)
Here's my deal. I basically have a square steel framed building with a metal deck. On two sides of my building(about in the middle of the building) the outside of the building jogs in approximately 2'-0". Therefor my chord forces are broken or my continuous load path is broken. Do I try and provide some sort of flat diagonal plate from one chord member to another? Or, do I justify my diaphragm as rigid and forget about my chord forces?






RE: Diaphragm Chord Forces
RE: Diaphragm Chord Forces
Mike McCann
MMC Engineering
RE: Diaphragm Chord Forces
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Make sure you calculate your maximum diaphragm moment and ensure your chords can take the load.
On another note, "forgetting about chord forces" implies your diaphragm is infinitely rigid... which cannot be the case. If you have a metal deck acting as your diaphragm, consider the diaphragm deflection vs. story drift for the rigid vs. flexible determination. In any event, your diaphragm will flex to some degree.
As an aside to everyone... wouldn't it be nice to have a simple AutoDesk (or similar) plug-in on eng-tips? Nothing fancy... just the ability to draw lines, basic polygons, leaders, and text. The advent of uploading files was a tremendous improvement -- now if the powers-that-be gave us the ability to draw in the message box, wow... I could probably just go out on my own and rely on my 650,000 strong e-office for advice and reassurance.
Best Regards,
JK
RE: Diaphragm Chord Forces
JKStruct, Is it safe to say if I meet the criteria in the ASCE7-05 Section 12.3.1.3 and Fig. 12.3-1 that I can assume the my metal deck is semi rigid? The kicker in the whole deal is can I really be in section 12.3.1.3?
RE: Diaphragm Chord Forces
JK: You can draw something in AutoCAD and plot it directly to pdf using PDF995 which is sponsored free. Then upload the pdf. Pretty easy.
RE: Diaphragm Chord Forces