Splice at Beam Stirrup?
Splice at Beam Stirrup?
(OP)
I am working on a project with an elevated concrete beam. The beam is fully loaded from above and will not experience any torsion. The stirrups in the beam were fabricated a few inches too tall. The contractor has asked to cut the stirrups just below the top to turn them into U-shapes. He would like to pair these cut stirrups together to create a closed loop. This would cover a half of the beam's length, and he would order correctly sized stirrups for the other half of the beam. The length of the vertical leg is long enough to meet the requirements of a Class B splice. This project is in Texas.
Can anyone think of a reason that this should not be allowed?
Thanks.
Can anyone think of a reason that this should not be allowed?
Thanks.






RE: Splice at Beam Stirrup?
BA
RE: Splice at Beam Stirrup?
RE: Splice at Beam Stirrup?
RE: Splice at Beam Stirrup?
RE: Splice at Beam Stirrup?
RE: Splice at Beam Stirrup?
RE: Splice at Beam Stirrup?
I have ACI 318-05. Section 12.13.5 gives requirements for splicing of pairs of U-stirrups to form a close unit. The commentary R12.13.5 - These requirements for lapping of double U-stirrups to form closed stirrups control over the provisions of section 12.15 - splicing of deformed bars.
The OP clearly says that the overlaps for U-stirrups meet Class B splice requirements. Therefore, pairs of U-stirrups may be acceptable within the middle-half of the span, assuming they are not expected to work very hard. A sketch showing splicing requirements and limitations on the use of that sketch can be issued.
RE: Splice at Beam Stirrup?
RE: Splice at Beam Stirrup?
Makes me think back to an argument I had on-site recently with a steel fixer when I picked him up for not having the ligs vertical.
RE: Splice at Beam Stirrup?
It's no trick to get the answers when you have all the data. The trick is to get the answers when you only have half the data and half that is wrong and you don't know which half - LORD KELVIN
RE: Splice at Beam Stirrup?
BA
RE: Splice at Beam Stirrup?
I would never allow such an adjustment, based on the actual function of the stirrups. Except in large members, the overlap of the u-stirrups will not develop sufficient strength for shear demand. (ACI 318 12.3.5 describes when that can be used.) The biggest problem with it is that behind only concrete cover, failure will be brittle once the capacity of the cover to restrain the lap spliced stirrup is exceeded. Stirrups must remain ductile to provide the intended warning in the event of shear failure, and a detail which has unconfined, lapped U-stirrups is a dangerous practice. (I will post a link to high speed video of some cover tests that were just completed, once the university approves them to be posted.)
The supplier should be permitted to either provide correct stirrups, or modify the stirrups in the fabrication facility. It sounds like they could be cut and bent to conventional open stirrups with 90 or 135 hooks. If the fix has to be done in the field (seldom the case), make absolutely sure that any field bending conforms to CRSI/ACI bend diameters for stirrups.