Steel Trapezoidal Plate as Diaphragm -No Topping Conc.-

[otto_eng]

Hi all,

I'm currently working on a project where I'm considering the use of a steel trapezoidal plate as the roof diaphragm for a single-story structure. If any of you have experience with this, could you please provide references, particularly concerning the horizontal shear aspect?

Thanks !

 

[BAretired]

Sounds very unusual. A sketch might be helpful.

 

[otto_eng]

It is not unusual. You may have seen such applications over warehouse type of structures or sporthalls..

 

[lexpatrie]

SDI Diaphragm Design Manual?

It sounds like you're using an odd term for something pretty standard, unfilled steel deck. Metal roof deck.

 

[strucbells]

Yeah this is just an untopped metal deck. Often can be idealized as a flexible diaphragm if you have a rigid lateral force resisting system like concrete or masonry shear walls. Verco also has some design tools available on their website to help.

I usually go with 20 gauge minimum, 18 gauge if I need it. 22 gauge often calcs out ok for smaller structures but I was taught years ago that it's too easy to beat up/warp during shipping and handling.

If you've never designed a diaphragm before, talk to your senior engineer and/or mentor about it, it takes a bit of learning the first couple of times.

 

[BAretired]

Okay, I agree it is not unusual. The term 'steel plate' was confusing me. I would call it steel deck. The picture appears to be showing a rectangular plan, not trapezoidal, but perhaps that is not an important difference.

The SDI document suggested by lexpatrie is a good one. Some deck suppliers supply information in their catalogs too...Canam for example.