Rebar Welding
Rebar Welding
(OP)
In relation to the welding of Rebar to a column to provide anchorage for an RC wall. Does welding reduce the strength of the Rebar itself by making it brittle. If so is there information on this in the British standards or Eurocodes or other documents. Thanking you in advance





RE: Rebar Welding
RE: Rebar Welding
RE: Rebar Welding
I can't provide you any further help because you don't have enough detail about the rebar chemical composition, weld joint detail or the material you are joining to the rebar (another rebar or steel plate). A way around this is to obtain a sample of the rebar, do a full penetration weld, and have a mechanical test lab run a tensile test on the welded rebar. This would provide you with the necessary information for this application.
RE: Rebar Welding
RE: Rebar Welding
You may also have to also have a look at the structural welding code for steel as well....allowable stresses, preheat, electrode selection etc.
What is the UK welding code for reinforcing steel...is it BS 7123...or is it a BS EN designated one?
Are the MPa values yield or tensile strength requirements? I suspect yield...no?
I am sure if you review the relevant UK welding codes, it will permit welding 460 MPa reinforcing steel to 275 MPa steel, if base metals are in compliance with codes and WPS is based on qualified PQR or tests of trial joints.
Whether your proposed joint will function in accordance with the model you have envisaged, is another matter.
RE: Rebar Welding
I would not specify welding rebar unless the material is weldable. That's creating a potential problem that you should know better than to do.
RE: Rebar Welding
It might be better to maybe thread the end of the bars and pass the bar through a cut hole in the flanges.
RE: Rebar Welding
Dik
RE: Rebar Welding
Yes, that is the yield strength.
BS 7123 is the code alright for welding rebar for quality of weld etc, BS4449 states the rebar to be used.
However the last thing I will need to find out or maybe you would know, when the rebar has been welded is there a reduction factor for loss in yield strength due to the heat etc. Im not looking for reams of mathematical formulae just maybe a simple reduction factor for a typical weld for calculation of steel needed. Maybe this is not available but thought id ask anyway. Thanks again
RE: Rebar Welding
if you weld the rebar and cannot achieve a full penetration weld, assume a 0.74 reduction factor in tension. For shear load, assume a 0.50 reduction factor.
RE: Rebar Welding
If there are welding problems,as listed above,use this old trick. Attach a piece of known good material to the rebar(preheat,E6010,wire weld,PWHT,etc.)may need to do some bends or testing. Then make your attachment from it.
RE: Rebar Welding
Yea that would be an option, except it will require a lot of onsite fabrication and welding which is not desirable.
metengr: those factors seem reasonable but could i just ask where they came from? thanks
RE: Rebar Welding
RE: Rebar Welding
metengr: I have a question on terminlogy for you. In D1.1-00 Table 2.3, which is similar, to D1.4-98 Table 2.1, allowable shear stress on fillet weld effective area, is given as 0.30 x nominal strength of filler metal. What is the proper term for the factor 0.30?
RE: Rebar Welding
I would call this a shear strength reduction factor. The shear strength is typically 0.60 x the UTS, whereas, the shear yield strength is 0.58 x the tensile yield strength.
The 0.3 is obviously an additional conservatism.
RE: Rebar Welding
No, unfortunately it doesn't. Only states that rebar of 500N/mm2 yield stress should be used. thats fine but I have to validate the strength of the connection against various forces, and to say the yield stress is still 500N/mm2 after welding is not correct.
I have been given reduction factors by metengr, thanks, but will have to find the exact code or standard they are from (British Standards). The reason for this is that when my design is auditted I have solid evidence of where the various numbers came from.