How to Connect Sloped Steel Roof Decking to Masonry Wall?

[mitchpo13]

Hi all,

I have a 5:12 sloped steel decking roof that's to be connected to a concrete masonry wall, but I'm not sure how to connect it. All the standardized literature I can find is for either flat roofs, or for connecting the decking to parallel beams.

Help me Eng-Tips Forums, you're my only hope.

 

[JedClampett]

Wasn't that a line from Princess Leia in Star Wars?
Normally, you get the steel decking as close as you can to the CMU, considering its slope and the CMU coursing, and attach a bent plate to a series of embeds (or one continuous embed) in the CMU. The top "flange" of the bent plate is bent to match the roof angle. Then the roof deck is welded or mechanically attached to the bent plate.

 

[JLNJ]

If you have no parapet you can have the mason cut the block to suit the roof slope, run the deck over the wall, and weld the deck to embeds in the sloping bond beam. Expensive, but effective.

 

[XR250]

I do it like JedClampett described.

 

[mitchpo13]

My only issue with the bent plate idea that JedClampett described is that I'm not sure the plate will hold. I was under the impression that angles and bent plates with a <90 degrees angle aren't meant to carry compressive loads on their flanges.

Has anyone actually implemented this connection?

 

[JedClampett]

I put the bend on the other side of the plate, so that it's >90 degrees, not less. But either way, I'm not sure I understand your concern.

 

[jayrod12]

@ JedClampett

HAHAHA. That's awesome, I wonder what they say about >270 degree bends

 

[mitchpo13]

@JedClampet

I was picturing the angle being attached to the roof from the inside, so that the roof would rest on top of it, but I believe you're talking about attaching it to the outside of the roof and the vertical facing of the wall. Your description makes much more sense to me.

 

[BAretired]

Provide a sketch.

BA

 

[ACE58]

Similar to JedClampett's response, I have used a continuous metal plate (usually 4" to 6" wide) w/ 1/2" diameter anchor studs shop welded to the underside of the plate. The slope of the plate matches the slope of the roof & the anchors are grouted into the top courses of the masonry wall(on top of the wall). The metal deck is then field welded to the plate.

 

[a2mfk]

Jed and ACE got it, seen and done it plenty of times without a problem. Just make sure to size your anchors to the wall for all your different forces: in plane shear from the roof deck, out of plane shear from the top of your wall, and good ole uplift. You can connect to the side or top of the wall depending on your detail, and they can cast headed studs or epoxy bolt after the wall is built.