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

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Gentlemen: Rebar welding is done everyday, all the time. Get a copy of AWS
D1.4. Get a temp stick for 400 F, run a torch over it, and start. The other
day we welded 8 #9 bars, preheated to 500 degrees, and used a full pen butt
weld with split pipe backing, just like the picture. No problem.





At 07:22 AM 10/1/96 -0600, Bellfi, Brian/DEN wrote:
>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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