4in width steel beam for 28 span

[Engin1]

I am working on a 4 story steel hotel building, the Architect only gave me 4" in width for about 28' long steel beam in all demising walls (separation of two rooms) and composite slab span from beam to beam (about 12ft). which means the max W shape beam i can use is W12x22, which is too small for the 28' span. HSS beams need more expensive connection than W beams. Anyone have any good ideas? Please help me, thanks!

 

[PEinc]

And your question is..........?

http://www.PeirceEngineering.com

 

[Engin1]

PEinc: Sorry! I clicked the 'submit post' button by mistake before I finished the editing. I just updated it.

 

[Agent666]

I've seen the following concept used sometimes in this situation using a welded beam:-

 

[JLNJ]

Use the HSS and tell the architect to deal with it.

You can probably come up with a bolted connection so that you don't have any field welding.

 

[KootK]

Yeah, if the HSS works, I'd not sweat the connection. Weld a tee on the end and shear tab it to the column.

Another option might be to weld a WT of the same section to the bottom for a new section depth of 18".

 

[Agent666]

I think as well some consideration of the flooring type and seating lengths is required. At 4" wide you could run composite deck over it, but at a minimum they usually require at least 50mm seating at end to end joints in my experience and often they don't 'overlap/nest' that nicely.

Once you consider seating tolerances/sheet length tolerances you maybe don't have enough flange width at 4"? Something additional to feed into your thinking at least. If you have to weld on plates, etc, to increase the width it adds expense.

 

[BridgeSmith]

Sounds like a job for a plate girder.

 

[hokie66]

If the beam is composite with the slab, will that work for your loading condition? You said "composite slab", no mention of composite beam.

 

[Engin1]

Thanks, everyone! I think it makes sense to use HSS with bolted connection.
hokie66: I tried composite beam with W12x22, it doesn't work.

 

[PEinc]

I don't know if you have any depth (height) restrictions in the wall but can you double up 2 WF beams, one above and connected to the other?

Can you use a truss?

This may be crazy, but how about making a beam out of two steel plates? Two, 1 1/2" or 2' x 12" plates bolted together would be a 3" or 4"w x 12"h beam with much greater S and I than a W12x22. Bolting them together would require more width or maybe they could be welded together.

http://www.PeirceEngineering.com

 

[BridgeSmith]

I like the idea of the stacked WF beams. You just have to weld them to connect the flanges. Not sure that would be any cheaper than having a plate girder fabricated, though. Something along the lines of the sketch Agent666 posted would be what I could see working.

Engin1, have you looked at the older "S" shape I beams? I think those are still available and some have more capacity than a WF shape with the same flange width. You might check some of the bigger channel sections, too.