26GSP,25GSP, and 24GSP Tendons?
26GSP,25GSP, and 24GSP Tendons?
(OP)
I am doing a load rating on a bridge built built in 1970 with post-tensioned tee section girders. Take a look at the attached as-builts. The tendon types are marked 26GSP, 25GSP, and 24GSP. Does anyone know what these mean? I want to know the strands area and ultimate stress so I can verify the forces shown on the sheet and know what is included in the stress losses.





RE: 26GSP,25GSP, and 24GSP Tendons?
Looks like grouted button-head system, using 1/4" dia wire, as the table states "shim length" which is a give-away for button-head system.
26 is the number of 1/4" dia wires, with a stated final PT force of 180 kips is about 140 ksi.
Maybe a PRECON or RYERSON - which were licensees for the original BBRV button-heads. When I get home I will check out my old notes and maybe able to post the data.
RE: 26GSP,25GSP, and 24GSP Tendons?
Button-head tendons are described by number of wires, type of sheathing, and type of end anchorage/s.
"GSP" nomenclature is:
"G" - GROUTED (alternative is MASTIC for UNbonded tendons)
"S" - STANDARD grooved washer to stressing ends
"P" - spreader PLATE to fixed-end
So in your case all your tendons are grouted, with standard grooved washer stressing ends, with spreader plate at fixed ends.
1/4" dia wire had a GUTS of 240 ksi.
From PCI PT Manual 1 Edition, 1972, Chapter 2:
RE: 26GSP,25GSP, and 24GSP Tendons?
RE: 26GSP,25GSP, and 24GSP Tendons?
Or use Ap of the 1/4" dia wire area as 0.049 in2 and UTS of 240 ksi and see if that checks out.
RE: 26GSP,25GSP, and 24GSP Tendons?
RE: 26GSP,25GSP, and 24GSP Tendons?
Good to help out a fellow engineer.
I know I have benefited many, many more times than I have contributed to Eng-Tips, so pleased to give back.
Happy 4th of July, or are 'so Aussie' that you celebrate Jan 26 instead!
RE: 26GSP,25GSP, and 24GSP Tendons?