DIYbanter - View Single Post - OT (kinda): Highway building code question

wrote in message
ups.com...
I know, I know, alt.building.construction, but I've found that y'all
know as much about this stuff as those folks, and I feel like nobody
who reads this group would possibly have the gall to post a reply on
point unless they knew for a flat-ass outright fact what they were
talking about.

I'm not going to let that stop me. ;-)

Background:
A friend of mine is working for the Army who is doing a construction
project for the Border Patrol in southern California. This project
mainly involves building box culverts, runoff slabs and road beds.
According to my buddy, these structures are built to interstate highway
specifications, even though a 5/4 ton pickup is the heaviest vehicle
these roads will probably ever see.

The Plot Thickens:
A Chief Warrant Officer (a surveyor by trade) told this crew, who was
putting in a steel rebar mat, that only every third joint be tied
together. This raised some discussion among members of the crew, one
of which swore that OSHA required that every joint be tied. This, to
me, sounds like a dumb-ass thing to say. ANSI maybe, but not OSHA.
Further, he swore that the joints could not be welded, as the welding
process weakens the steel. Also completely ridiculous as far as I can
tell, in the context of the concrete system.

I don't see how OSHA would be involved, and I doubt there is an ANSI
standard either. There may be an ACI (American Concrete Instutite)
standard, or the DOT may have their own standard.

I told him (my buddy) that local building codes vary (and are all
subject to the building inspector) but the only reason rebar gets tied
or welded together in a concrete system is to hold it in place until
the 'crete gets poured over it. 8 hours after the pour, that little
piece of wire has done its job. I further told him that perhaps
welding rebar may weaken the steel at that point, but does not have a
significant effect on the overall strength of the concrete system.

I consulted my wife who about a million years ago as a civil engineering
student did a summer internship with Illinois DOT inspecting road
construction. Her recollection is that they did not tie every rebar
intersection together. After compacting the road bed, the chairs are put
into place and the rebar is laid down over that. She agrees that the only
point to tying the rebar together is to keep them in place while the
concrete is poured. So, tying every single intersection together would be
overkill. Here in the North, the rebar is epoxy-coated, so welding would
kinda screw that up. But where your buddy is, there may not be a
requirement for epoxy-coated steel due to the lack of salt applied to the
roads.

todd