interior steel floor girder parallel with steel deck

[goodriws]

This question is not about whether or not steel deck parallel to a steel beam braces the top flange. However, in a typical steel-framed building, the concrete slab & metal deck span over the beams and run parallel to the girders. My question is construction-related: before the concrete is placed, as they are laying out the deck, do the sheets of deck 1) stop on either side of the girder or 2) sit on top of the girder? The advantage to 1) is the contractor doesn't have to cut the deck around the column. The advantage to 2) is he doesn't have to use closure strips, etc.

I'm sure it's been done both ways, but I'm hoping someone can say which is done considerably more often or which one is "better" from a structural integrity standpoint.

Thanks in advance.

 

[BAretired]

Is the girder composite with the slab?

BA

 

[spats]

If this is composite construction, it's normal to split the deck and haunch the slab at the girder. It does not, however, "stop on either side of the girder". The deck on each side sits on top of and is connected to the girder with puddle welds. Closure strips are often required. This way the composite studs can be welded directly to the top flange, rather than through the deck, and you get a better weld.

If it's not composite, the deck is continuous across the girder, and closure strips are avoided. In any event, you need to consider what is acting as your diaphragm, the concrete or the deck, and proceed accordingly.