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[SEAOC] RE: [SEAOC] Re: [SEAOC] Welded Rebar advise needed

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There is weldable rebar these days.  The specification that I am aware
of is ASTM A706 Reinforcing Steel.  This is used in bridge construction
due to the controlled yield strength, for seismic design, and because of
its chemical properties such as weldability.  

You may be able to weld ASTM A615 Steel but, there are preheat
requirements that are very difficult to achieve and control in the
field.

Brian Bellfi
CH2M Hill
>----------
>From: 	James M. Warne[SMTP:jwarne(--nospam--at)direct.ca]
>Sent: 	Monday, September 30, 1996 10:30 PM
>To: 	seaoc(--nospam--at)power.net
>Subject: 	[SEAOC] Re: [SEAOC] Welded Rebar advise needed
>
>At 05:13 PM 9/30/96 -0700, you wrote:
>
>>I want to resist uplift ( with 7/8" diameter threaded rods welded to #6
>>rebar
>>(jamb bars) embedded into the footing. 
>
>Did you know that rebar welding is often unreliable, unless special
>procedures are followed, or unless "weldable rebar" is used? It's not common
>in the field. The problem is the high carbon content which leaves everything
>very brittle, and the start of the weld is a stress raiser.
>
>If the wall isn't built yet, try an ordinary lapped splice. You can put nuts
>and washers on the threaded rod to get anchorage equivalent to the deformed
>rebar.
>
>If you're stuck with existing rebar and the projection isn't enough to
>develop the tension, you may be able to bend it into a hook, or thread the
>rebar for a coupling splice. I guess you CAN weld if you have to, but you'll
>need a good welder with good equipment, and special supervision. There are
>probably better alternatives, such as drilling in some anchors somewhere,
>instead.
>
>The base plate should bear on concrete, but it sounds like you'll be
>grouting the masonry, so it could still be on concrete at masonry level.
>You'll probably want some flowable grout under the base plate. Putting the
>base plate on top means the bolts have to stick out and might be in
>somebody's way.
>
>I hope I understood the situation. I gather the "header" is like a lintel.
>"CMU" is a TLA* I haven't heard in Vancouver - perhaps Concrete Masonry
>Units?
>
>                                                           *"Three Letter
>Acronym"
>
>Jim Warne
>
>...
>
>

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