Most efficient way to create bearing surface for decking?
Most efficient way to create bearing surface for decking?
(OP)
An existing 6in slab is poured directly on beams at 5ft spacing without decking (the original contractor must have used removal/reusable formwork). The top of the beam flanges are embedded .75in inches into the bottom of the slab without shear studs resulting in a 5.25in deep slab over the beams. We need to remove the slab in some areas and replace it with 1.5in deep grating (I assume you can saw cut concrete directly over the flange of a beam?). This leaves a gap of 3.75in between the top of the beam flange(s) and the bottom of the welded metal decking. 1.5in deep decking is used to match the decking on the rest of the project.
What is the most efficient way to fill this 3.75in gap while also providing support for the metal decking? I am planning on having the contractor weld an HSS3.5x3.5x1/8in running parallel to the beam directly to the top of the beam flange and then weld a 1/4in plate on top of the HSS section. Is there a more efficient way to do this?
Also, is there a way to calculate how much load an HSS section can take compressing two opposite faces and is there a way to calculate if 1.5in is enough bearing distance for the metal decking?
What is the most efficient way to fill this 3.75in gap while also providing support for the metal decking? I am planning on having the contractor weld an HSS3.5x3.5x1/8in running parallel to the beam directly to the top of the beam flange and then weld a 1/4in plate on top of the HSS section. Is there a more efficient way to do this?
Also, is there a way to calculate how much load an HSS section can take compressing two opposite faces and is there a way to calculate if 1.5in is enough bearing distance for the metal decking?






RE: Most efficient way to create bearing surface for decking?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Most efficient way to create bearing surface for decking?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Most efficient way to create bearing surface for decking?
RE: Most efficient way to create bearing surface for decking?
RE: Most efficient way to create bearing surface for decking?
http://www.mcnichols.com/product/6402310132?navCod...
I asked the manufacturer for the required bearing length for the metal grating and they said it's up to the engineer, is there a way to calculate this? The floor loading is 75psf.
I'm weary of connecting to the existing concrete to support the new metal grating as it has plenty of cracks. Is there anyway to know which is the cheapest option: the WT (does this need stiffeners?), the HSS & plate, or the 1/4" plate bent into a channel?
RE: Most efficient way to create bearing surface for decking?
RE: Most efficient way to create bearing surface for decking?
RE: Most efficient way to create bearing surface for decking?
For grating, deck crippling isn't a possibility and steel on steel bearing capacity is extremely high. If there's a check to be done I suppose it would be crippling/yielding/buckling of the 1/8" HSS walls. To be honest, I would never have thought to check that if you hadn't brought it up. 1.5 in of bearing will be plenty.
None of the alternatives is cost prohibitive. Some thoughts:
1) You'd have to stabilize the WT while welding it.
2) HSS involves flare bevel welding which can have QC issues.
3) Bent plate requires some shop effort but can be welded down cleanly.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.