Column to metal deck screws/weld

[PROFR]

We are building a vertical metal deck wall behind a masonry wall that will be taking an earth pressure as shown to strengthen it. We are temporary screwing the metal deck to the wall and then installing the steel columns to laterally support the metal deck. We need to tie the deck to the flanges of the column to laterally support the flange. Typical deck screws will not work because they cannot be done from the other side of the deck. What is the best to do to attached the deck to the flange? bolts? screws? weld?

 

[r13]

Tack weld.

 

[JLNJ]

Size the steel up so that it doesn't need the lateral support. People who weld are expensive. Steel is cheap.

That wall must be in really bad shape if the relatively flimsy deck is stiffer than the CMU wall.

 

[Agent666]

Surely in this scenario the existing masonry wall is orders of magnitude stiffer spanning horizontally than the deck. So deck basically doing nothing if its not composite with the masonry?

I'd hazard a guess the Masonry wall just spans horizontally to the steel and deck is a bit redundant.

Would you strengthen a slab like this to turn the problem 90 degrees? I don't think so.

 

[PROFR]

Agent666,
The wall is full of cracks and therefore we are ignoring any contribution from it.

 

[BAretired]

Sounds like a job for reinforced pneumatically placed concrete (Gunite).

BA

 

[Ron]

In order to weld the deck in a vertical position, you would have to qualify the procedure, since puddle welds typical of deck attachment are not qualified for other than a flat position. It would be difficult to achieve a sufficient weld in a vertical position.

I would use mechanical attachment....either TEKS screws or powder actuated fasteners.

 

[KootK]

1) I like JNLJ's idea of designing the columns to not require lateral bracing. Alternately, you could provide one or two levels of bringing / roll beams. That's bound to be more expensive than a no bracing solution I expect. Whatever you do for fastening, it may not be long lived if the root issue here is a waterproofing issue that doesn't get solved excellently.

2) you could screw or weld a flat, vertical sheet of cold formed strip plate to the exterior column flanges that overhangs the flanges a couple of inches. Then screw that to the deck.

 

[PROFR]

Kootk,
If the deck is gauge 16, Cannot we just weld using a 1" length 1/16 thick weld the deck directly to the flange?

 

[gtaw]

You can weld the decking to the structural columns.

You can use SMAW with small diameter electrodes. E6013 or 7018 will work, both have shallow penetration characteristics. The will be a tendency to burn through the thin sheet steel if the welder lingers too long trying to get good fusion to the column. It will be a benefit to the welder if the edges of columns where the weld will be located were ground to bright metal to eliminate mill scale.

GMAW short circuiting could be used, but the low heat input would result in a strong tendency to produce incomplete fusion defects. Pulse spray would be a better choice (than short circuiting), but the equipment is much more expensive and it may be difficult to do in the field due to the need to use a shielding gas. The same issue with the shielding gas would be present with GMAW short circuiting transfer. A wind screen of some sort would minimize the problem of the shielding gas being blown away.

The success of such a venture would hinge on the skills of the welder. Welding thin to thick material is always a challenge, but it can be done with the right controls in place and as mentioned, skilled welders.



Best regards - Al