Thank you Ian! I agree, if we were the EOR for this, we'd just use the dedicated pick point or wagon wheel as you suggest. In this case, the operation and engineering is being done by a subcontractor, and we are only performing a design review. I wanted to get some guidance from outside of our company, so that we can demonstrate that our recommendation to use a dedicated pick point is not something that is out of the ordinary and would be considered a best practice. Your response above will certainly assist with that.
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Angela Hunter P.E., C.Eng, M.ASCE
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Original Message:
Sent: 07-24-2023 09:43 AM
From: Ian Ebersole
Subject: Lap spliced hoops for drill shaft rebar cage
Hi Angie --
Usually, by the time a cage is big enough for an engineered lift plan, we're bypassing the hoops anyway to rig to a dedicated picking ring or wagon wheel. I suppose sometimes you can get away with a doubled or oversized hoop for the trailing crane, but not always. We have used lap spliced hoops for the doubler in those instances without issue (although they were choked by rigging, which may have helped).
As such, I don't think I'd be concerned with a lap spliced cage from a lift engineering perspective. I could see having a rodbuster on hand as the cage is lowered into the shaft to confirm that none of the hoop splices have loosened during the tripping operation.
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Ian Ebersole P.E., S.E., M.ASCE
Technical Lead
Foothills Bridge Co
Boulder CO
Original Message:
Sent: 07-19-2023 09:28 AM
From: Angela Hunter
Subject: Lap spliced hoops for drill shaft rebar cage
A project is using lap spliced hoops for their drilled shaft rebar cages. I have yet to come across this in my career - we've always had welded hoops and/or spirals. The team has some ideas regarding how to address this locally at the lift points, but wanted to put this out there for feedback to find if any of you have experience in lifting/upending drilled shaft cages with lap spliced hoops and how it was addressed from an engineering standpoint. Any input or feedback is appreciated!
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Angela Hunter P.E., C.Eng, M.ASCE
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