precast concrete tanks (precast panels over cast in place base)

[NADOR123]

Hi everyone,

Has anybody run structural analysis of the precast multi-cell concrete tanks.
The way this tanks constructs is pouring cast in place base slab usually 12" thick with grooves 4" deep at the location of exterior walls and interior wall dividing the cells and the groove is about 7" wider than the wall thickness (10") at the top and 1 1/4" wider than the panel thickness (10")at the bottom of the groove.
The groove then filled with grout. The panels connected together by groove and tong throughout the height of the tank, at the top of the slab, dowels to be installed to connect a 6' top slab with access openings. The details show the 4" groove depth as a cover above the top layer of the base slab reinforcement.
My concern whether the 4" groove filled with grout can be considered a good support to the panels under the loading case of one side of the tank full and the other side empty or soil fill on one side and the tank side empty with liquid pressure shear on the four inches cover of base slab and the stability of the panel during the construction beside the water tightness issue due to the walls and floor/walls of the joints patched with grout. Also if any structural problem can be caused at the section where vertical joints capability to carry liquid load.

 

[JedClampett]

Sounds like you're not going to have a problem with water on just one side, because the water will leak out of that joint in a big hurry.
Has someone done these before? It's hard enough to build a cast in place wall water tight, but a house of cards like that...

 

[Brad805]

There are some very large PC companies building exactly these and have been doing so for years. I assume they are post tensioned? I recall finding a great supplier that had a lot of information on their website years ago, but I could not find it right now. As for the analysis, unless you are the supplier, this might be something to discuss with the successful proponent.

Brad

 

[hokie66]

Tanks built this way are always circumferentially post-tensioned. It is an economical (cheap?) way of building a tank. This type construction should only be attempted by those with a lot of experience who have already learned what can go wrong. There are a lot of tanks around like this, and there have been a few spectacular failures.

 

[JedClampett]

Preload

http://www.preload.com/index.html

uses this method to build tanks. They've got to be round and they have to be prestressed. I'm not sure how you would make them multicell. And the details are way more complicated than setting a panel in a bed of grout.
Westminster California had a 5,000,000 gallon tank fail in 1998 that was built using this method. No one was killed, but it caused a lot of damage. The cause was traced to a contractor not following details, if I remember correctly. See

http://articles.latimes.com/1998/sep/25/local/me-26262

 

[hokie66]

There are some post-tensioned tanks built which are not round, but round is the most efficient shape structurally.

http://close-associates.com/newsite/wp-content/uploads/2010/03/CI-final-draft.pdf

Using Google will find lots of similar information about constructed tanks. Your best source is probably VSL or one of the other major post-tensioning companies. Most of these tanks are design-build projects, so hopefully the engineers have already accumulated the experience, both good and bad.

 

[amec2004]

See attached Circular Precast Concrete Tank details and photo from Con-Force

We have done a lot of this as Thickener Tank to process oilsand tailing


anchor bolt design crane beam design

http://www.civilbay.com

 

[amec2004]

Here the photo



anchor bolt design crane beam design

http://www.civilbay.com