Reinforced Tank Design- The Slab
Reinforced Tank Design- The Slab
(OP)
How is the tank slab thickness determined? The reinforcing is typically based on the thickness of the slab and I have been able to find references on designing reinforcing for slabs on grade, but nothing on the selection of thickness for the uniform hydraulic loading in a tank.
RE: Reinforced Tank Design- The Slab
--Strength of the subgrade/subbase
--Strength of the concrete
--Magnitude and type of loading
Since your loading is uniform and the slab is ground supported, there isn't much need for reinforcement other than to control shrinkage cracks. Assuming your liquid level doesn't exceed about 20 feet, you will have a uniform load of about 1250 psf (assuming Sp. Gr. = 1.0 (water))At or below this value, it isn't necessary to consider slab bending assuming your modulus of subgrade reaction, K, is greater than about 150 pci.
I would suggest a minimum concrete strength of 4000 psi, using as large an aggregate as practicable. Reinforcement would likely consist of at least one mat of 6x6-W4.0 x W4.0, placed at the center of the slab. The slab thickness would likely be in the 6-inch range, but you can check that analytically through any of the pavement slab design procedures (contact pressure = 1250 psf or whatever it happens to be). A good reference for this is "Slab Thickness Design for Industrial Concrete Floors" by Robert G. Packard, Portland Cement Association, Skokie, Il.
This is a variation on a pavement thickness design problem.
RE: Reinforced Tank Design- The Slab
RE: Reinforced Tank Design- The Slab
RE: Reinforced Tank Design- The Slab
RE: Reinforced Tank Design- The Slab
RE: Reinforced Tank Design- The Slab
RE: Reinforced Tank Design- The Slab
RE: Reinforced Tank Design- The Slab
1.Moment at the wall and base junction. Which is more if wall is considered as cantilever, and appropriately less depending on top and side end conditions of walls of rectangular/square tanks.Much less if the tank is circular because of hoop pressure.
2.If the tank base is below the ground level and the ground water table is high, there will be an upword presure on the base slab when the tank is empty. The slab has to resist this moment and that governs the steel many times. In this case the slab bends like any suspended slab between the walls.
3. Usually a minimum thickness of 6" to 8" is specified for water tightness irrespective of moments with minimum steel.
RE: Reinforced Tank Design- The Slab
Crteria: Capacity 10,000 US gals, format square. wall height8' To Be cast in place.
Thanks for any design guide info. This is for a volenteer project(Romanian orphanage)
RE: Reinforced Tank Design- The Slab