I just got to leave work and go home where I am on Dad duty. My interpretation of the guide is that it was meant for all situations. I would think it would be silly to make a guide for only short length reinforcement.
I do know that there is "engineering stuff" that has to be done which is the...
Also here is a quote "Since the tensile capacity of the reinforcing section is resisted by the welds of the cut-off points, and compression stability is not an issue, the designer needs to only consider a weld spacing that satisfies the requirements for built up tension members given in the LRFD...
I just downloaded a guide from AISC. In the example they sized the welds at the cutoff points for the Fy * Ag. Then they used a minimum 1/8" x 2" weld at 12" on center for the intermediate welds. No calcs required for the intermediate welds. They didn't use VQ/I. This kind of goes with what I...
The slides from AISC made me believe that the welds at the end ensure composite action. The welds in the middle could be the minimum required but it is good practice ("prudent") to do VQ/I for those welds. AISC F13.3 requires that welds be placed in proportion to vert. shear that is why the big...
@canwesteng
The 6" is from the point of max moment to the point of zero moment for my 12" long beam. I do agree that the anchorage length is there to ensure full composite action while the VQ/I for the rest of the beam is conservative.
Thank you @ Celt83. That power point by AISC is gold. Slide 111 says that the ends of a retrofit WT welded to an existing beam are welded at the ends for "full yield". This to me means the tensile capacity of the new member. Then they provide VQ/I intermittent welds as kind of a safety factor. I...
I think I misunderstood the OP. Now that I've reread it, I think you're saying you should be using the higher force associated with plastic moment capacity to design the weld. If so, I think I would agree. The strength design for shear studs in composite bridge girders is essentially approached...
Thank you @BridgeSmith and @RPMG. I attached a "proof" where I tried to show what I am thinking on this. Take a look and let me know what you think. I am studying for the SE and trying to get my P's and Q's in order, thanks for your help! Happy New Year...
I have done a lot of steel retrofit and usually this involves welding a plate to a beam or similar. Often it is more economical to use the full plastic capacity to get the plate size if top flange is braced.
If I am using the plastic capacity of the plate it seems wrong to me to then use VQ/I...
