Epoxy coat carry bars at top of slab?

[bvass]

Hello - I've got a question that popped up during shop drawing review of mild reinforcing of an elevated garage slab (w/ PT). To protect the reinforcing bar in the garage, the design team has agreed to epoxy coat all the mild reinforcing located at the top of slab. As a construction practice, contractor's often use 'carry bars' as a method to lay out PT. These carry bars are purely means and methods for installation however. My question is, should these bars be epoxy coated as well since they are located within the top portion of the slab? If they corrode will this adversely affect the design strength of the slab? Since we are not counting on them for strength, I'm under the opinion they do not need to be epoxy coated. However, if this causes inconsistencies throughout the slab if and when corrosion does take place maybe it's a good idea to require epoxy coating? I've attached a snapshot of the question for more clarification. Thoughts? Thanks in advance your your help!

 

[TehMightyEngineer]

Boooo, evil epoxy coated bars.

Alright, that out of the way; I'd epoxy coat them as well for many reasons. First, it's less confusing for the contractor and typically takes very little extra cost and work.

Second, while you don't need those bars for structural reasons you don't want them corroding and rust jacking the concrete off. They also do provide some reinforcement for what it's worth. They would be hard to distinguish whether the bars that are corroding are just your plain carry bars or the actual structural reinforcement.

Finally, corrosion is insidious. If one bar corrodes it could spread to the adjacent bars, perhaps through a notch in the epoxy coating where the bars meet. Best to try to eliminate this corrosion "transfer".

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com