RTU Connection on Composite metal deck

[Struct_Neat]

I have a 3 1/2" concrete over 2" metal deck. I have various mechanical units sitting on top of this deck. I am looking for ways to attach these units to the structure. How does the TYP industry connection work? If the mechanical units are sitting on curb, how does curb attached to the deck? Does it need steel framing below or it can be attached to the composite deck?

 

[Harbringer]

Expansion anchors or if needed you can thru bolt to an angle or plate below. Whether you need actual framing below depends on the demand.

 

[milkshakelake]

Agreed with Harbinger. It really depends. If it's a light unit, expansion anchors should be fine. If it's something substantial, then you might need to reinforce the joists below and do thru-bolting and stuff.

One common way to do this for heavy units is to cut out some of the deck and weld a post of some kind (HSS, W, etc) directly to the W steel below to raise the RTU. Obviously, adapt as needed based on what's below, in case it's open web joists or something else.