Metal deck to steel beam weld

[Triangled]

The HVAC curb was roofed in before the puddle welds from the deck to the new steel framing was performed.
Is there a way to complete this connection from below the deck?
It is in a region of low wind and seismicity.
Thanks!

 

[msquared48]

Certainly can't puddle weld from below.

Maybe screws, but then the screw points would be penetrating into the roofing material, an eventual leak.

Offhand, I would say no. Contractor's omission - rip and replace here...

Mike McCann
MMC Engineering

 

[SteelPE]

Was the deck not welded to the beam or was the RTU curb not welded to the beam? I find it hard to believe that the roofer went so fast that the erector never finished the deck welding before it was roofed.

In any event, take off the roof and attach from above as required. Trying to screw from the underside of the deck will be difficult and almost impossible to inspect to see if they got everything right or not. You also have to remember that your beams are relying on the deck diaphragm to provide lateral torsional buckling resistance. W/o proper attachment your beams may not work.

 

[TDIengineer]

Where the deck is perpendicular to the beam, can they provide a fillet weld to the edge of the beam flange and to the deck?
Where the deck is parallel to the beam, have them add a flat plate from the edge of the beam flange and reach over to the next low flute. Provide a butt weld to the beam flange, and fillet weld to the deck.
Wouldn't that lock the deck down to the beams and transfer the diaphragm shear to the beam as well as provide your top flange bracing?
Note: The deck is still somewhat bracing the top beam flange since friction from the deck bearing on the beam is providing some resistance. But we like to ignore friction in the event of vertical seismic loading, but you did mention low seismicity.

There should be a retrofit here that doesn't require tearing things out in this case..is my thought.

 

[Triangled]

Thank you all.

 

[ztengguy]

What TDI Said, but make sure they dont catch the roof on fire welding if inusl and membrane is down.

 

[XR250]

You can screw from below if there is insulation on the roof. Angles must be pre-drilled as the Tek screws won't work properly going from 1/4" to 22ga or so.
Also, make sure they don't puncture the membrane by drilling too far.

 

[Triangled]

Very helpful, thank you. There is insulation on the roof.
Appreciate the fire caution and the compression flange reminder.

 

[Triangled]

I'm having them slot the roofing and install the puddle welds as planned.
I appreciate the moral support, the cautions, and especially the clever alternatives which I'll keep in my back pocket for 'the next time'.