Welding Rebar from 1910

By JKG Date 01-22-2004 17:37

I'm involved with the structural repair of a concrete building built 1910 that is severly deteriored in many locations. I've ordered tests on rebar samples to determine weldability and am awaiting results. I'm guessing the rebar is ASTM A-15. The bars are typically smooth rounds, squares, and twisted squares.

Should I expect to be able to field weld new bars to these bars? Is there a maximum carbon content that is permitted? I'm looking at using double-bevel or double Vee butt welds. Any other advice or references to tech docs would help.

By CHGuilford (****)

Date 01-22-2004 22:05

I'm sure you will be able to weld the existing rebar with something. Just what that is I can't say but my guess for a good place to start is to try E7018. It's tough, has good ductility, and is relatively easy to weld with.

With material from that time period, it's hard to say what you will find. I don't have my code books handy but it may be that your situation doesn't fit code provisions anyway. Your testing will prove to be the most valuable information.

Don't overlook the lap joint if you have room for it. You could use a grade of material between the bars that provides a good transition in carbon content between the re-bar and the new material. That way the "old" stuff doesn't directly weld to the new if there should be a compatibility problem.

Chet Guilford