concrete vault for water line
concrete vault for water line
(OP)
Hey all - I'm working on the design for an underground vault to house valves for a 42" water line. It's gotten a lot more complicated than I anticipated and I'm not sure of the best way to go about designing the critical wall. Inner dimensions are 17'-4" x 10' x 9'-11" deep.
The short wall is the critical wall as it has an enormous amt of thrust. Here's what we're looking at:
surcharge load on soil above - large - aprox 5330psf (unfactored)
active soil load on wall
thrust force (due to water hammer) where pipe enters wall - 497,677# (factored)
I've designed the long wall as a plate and that went fine. I'm not sure how to design the short wall. My initial thought is to design as a small beam section (one in each direction), taking a chunk of the thrust plus the other loads? Bottom is fixed and top would be pinned.
I'm not worried about the over all sliding- I'll address that w/ wingwalls and keys. I'm just worried about the wall surrounding the pipe entrance.
Any thoughts or suggestions appreciated!
The short wall is the critical wall as it has an enormous amt of thrust. Here's what we're looking at:
surcharge load on soil above - large - aprox 5330psf (unfactored)
active soil load on wall
thrust force (due to water hammer) where pipe enters wall - 497,677# (factored)
I've designed the long wall as a plate and that went fine. I'm not sure how to design the short wall. My initial thought is to design as a small beam section (one in each direction), taking a chunk of the thrust plus the other loads? Bottom is fixed and top would be pinned.
I'm not worried about the over all sliding- I'll address that w/ wingwalls and keys. I'm just worried about the wall surrounding the pipe entrance.
Any thoughts or suggestions appreciated!






RE: concrete vault for water line
Some of your other forces look a bit high also. A surcharge of 5330 psf converts to an additional 42 ft. of soil.
If the thrust force is 500 kips, you're not only going to have problems designing the wall, but problems getting the force from the pipe to the wall.
RE: concrete vault for water line
RE: concrete vault for water line
I haven't designed one of these before but it sounds like I may need to go through the details of the restraint and the thrust force with them???
As for the surcharge... It was created based on an assumed load of a very large backhoe servicing the vault - both the weight of the backhoe and the lid section of the vault that it will be lifting. I designed the long walls with this surcharge and they didn't seem excessive.
Thanks for the input and any additional advice is greatly appreciated.
JAH
RE: concrete vault for water line