PSUEng11
Structural
- Aug 30, 2012
- 10
Good afternoon all, I was browsing and found this older thread: thread378-191855. It is a similar question to the problem that I am working on now. I just want to verify that I am on the appropriate track
I am working on a project involving cables and the owner wished to use a pipe as a portion of the anchoring system for the cables. The initial idea was to have a 24" diameter pipe approximately 10' off the slab, with three evenly spaced A-frame supports. The two cables were spaced approximately 10 feet apart with 2.5 feet on either side of the cables to the end supports. The cables each have a load of approximately 70.2 kips. They want to wrap the cables around the pipe and then run the cables down to be anchored to the concrete below. I was looking at the pipe from a wall crushing standpoint and I was running in to a few questions.
First, the equations that I am using are
- For the radial stress: P = 2T/Dd, where P=, T= tension on the cable, D=pipe diameter, and d=cable diameter.
- For the collapsing pressure on the pipe: Timoshenko's Formula for collapsing pressure of a steel casing (primarily used for well casings) See
What I was running in to was that my Collapsing Pressure was fairly low, while my radial pressure was significantly higher, therefore the pipe would be in danger of collapse from the radial load transferred to the pipe. I haven't fully set on a pipe size or thickness yet, but I wasn't sure if I could increase the wrap the cable to increase the contact area as a means to reduce the radial stress on the pipe. Thoughts on this?
I am working on a project involving cables and the owner wished to use a pipe as a portion of the anchoring system for the cables. The initial idea was to have a 24" diameter pipe approximately 10' off the slab, with three evenly spaced A-frame supports. The two cables were spaced approximately 10 feet apart with 2.5 feet on either side of the cables to the end supports. The cables each have a load of approximately 70.2 kips. They want to wrap the cables around the pipe and then run the cables down to be anchored to the concrete below. I was looking at the pipe from a wall crushing standpoint and I was running in to a few questions.
First, the equations that I am using are
- For the radial stress: P = 2T/Dd, where P=, T= tension on the cable, D=pipe diameter, and d=cable diameter.
- For the collapsing pressure on the pipe: Timoshenko's Formula for collapsing pressure of a steel casing (primarily used for well casings) See
What I was running in to was that my Collapsing Pressure was fairly low, while my radial pressure was significantly higher, therefore the pipe would be in danger of collapse from the radial load transferred to the pipe. I haven't fully set on a pipe size or thickness yet, but I wasn't sure if I could increase the wrap the cable to increase the contact area as a means to reduce the radial stress on the pipe. Thoughts on this?
