Slab on metal deck over masonry

[Boiler106]

we rarely get this condition, but i frequently see on other's drawings the slab on metal deck placed over load bearing walls with no positive connection to the wall prior to placing the slab.

the attachment is sometimes made with a dowel from the masonry wall to the slab, otherwise, the deck is resting on the wall.

I would think for erection safety it would be necessary to weld or screw the deck down. Am i missing something?

 

[jayrod12]

WE always have an embedded continuous weld plate when we have deck supported directly on masonry walls.

 

[Boiler106]

im glad we're on the same page. i see this detail on the "big name" drawings in several projects.

 

[jayrod12]

Maybe there's something buried in their general notes that doesn't show up on their sections. Honestly my experience at reading the "big name" company drawings often leaves a lot to be desired they bury so much in 2 pages of general notes and then have these generic typical details that really have almost no useful information.

 

[WesternJeb]

This seems more means and methods based to me, which is why I haven't called it out at times when I have something like a dowel bar sticking up to tie into the slab.

 

[IceNine]

Honestly my experience at reading the "big name" company drawings often leaves a lot to be desired they bury so much in 2 pages of general notes and then have these generic typical details that really have almost no useful information.

And they typically put it on the contractor to pull the appropriate information out of sheets and sheets of typical details and schedules that cover every imaginable situation, most of which aren't applicable to the project.

 

[jayrod12]

I fail to see how the connection between steel deck and the supporting wall is means and methods.

To me that's akin to saying, I showed a beam, but the sizing of it is means and methods.

 

[dik]

We use a BAR 1/4x4 with headed studs and 'puddle weld' to it.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[phamENG]

I get where WesternJeb is coming from - that's a formwork connection. It just so happens that the formwork will remain in place. But if there's no shear or uplift going through it, I get it. Don't like it, but I get it.

I usually use a continuous angle. That way, I can tell them to hold the grout down an inch to create a key for the slab into the block. The plate wrecks any connection between them. Of course, if the primary load path is through the steel anyway, it works out. But still a pain to grout around a continuous plate.

 

[Boiler106]

phamENG, this is the route i think i would take, too. i was wondering how you might dowel and connect to a headed stud plate without interferences and could only come up with a bolted seat angle and field-bent dowels.

what spurred this thought is that i recall reading about deck failures where the slab was to be connected to a seat angle on the web of a beam but was never welded. The beam rotated and the deck slipped, causing injuries.

 

[jayrod12]

I had assumed composite deck, and therefore structural beyond just permanent formwork. That being said, our general notes have a minimum specification for connection included.

Where I practice, if the deck isn't structural beyond formwork, we often don't even show the deck. If the contractor would like to use deck as formwork instead of building more conventional formwork, then that's on them to propose and provide the details including anchorage.

 

[WesternJeb]

See, we provide callouts for 9/16" formdeck and check it for construction loading, but not the angles. Funny how we all have different methods but it gets built all the same.

 

[Boiler106]

for the purpose of this post, im looking at 5 1/4" total slab thickness with 2 inch composite metal deck spanning 10ft.

 

[Enhineyero]

Maybe there's something buried in their general notes that doesn't show up on their sections. Honestly my experience at reading the "big name" company drawings often leaves a lot to be desired they bury so much in 2 pages of general notes and then have these generic typical details that really have almost no useful information.

Of course how else would they get a return on their 4x charge out rate that would need to trickle down from the Owners>CEO>VP>Regional Managers>Structural Manager>Team Leader>Senior Engineer>Engineer>Drafter plus not to mention the admin staff (HR, Accounting, IT, Marketing, Sales).

for the purpose of this post, im looking at 5 1/4" total slab thickness with 2 inch composite metal deck spanning 10ft.

if its reinforced CMU we have the tray stop start just near the centre of wall, then dowels connecting slab and CMU. If its brick then the tray just sits on top of the slab (need to check for lateral force/notional load against friction resistance of wall/slab junction - normally not enough if earthquake load/wind load is large).