Waster Water Concrete Bottom Slab Design
Waster Water Concrete Bottom Slab Design
(OP)
I need help. I have been asked to perform a preliminary design for a concrete slab design for a waste water tank. The sides are steel (CST Storage tank). I know ACI 350 gives the shrinkage and temperature steel requirements for the slab but how do you determine how thick the slab should be? The tank is 61' in diameter and has 19.26 of head. Allowable soil bearing pressure is 3500 psf.
Thanks
Berniedog
Thanks
Berniedog






RE: Waster Water Concrete Bottom Slab Design
Steel tanks in wastewater are kind of rare. Coating them is a major headache.
Next, does the tank have a steel bottom? Or is it attached to a steel angle, bent to the diameter of the tank? They're completely differnt designs and details.
RE: Waster Water Concrete Bottom Slab Design
CST is a manufacturer of steel storage tanks (http://www.cstindustries.com/Applications/Above-Gr...). There is no steel plate on the bottom. Along the outside ring they embed a steel plate with seal strips to make everything watertight.
THanks
RE: Waster Water Concrete Bottom Slab Design
At the ring, I would make sure the slab can carry the weight of the water plus the tank above it. To fit everything in, you'll need at least 12 inches. Add circumferentail reinforcing at the ring to take the hoop stresses, even though the embedment detail could probably handle them on it's own.
RE: Waster Water Concrete Bottom Slab Design
You would not place the #5's @ 12" o/c. in a radial type layout would you?
RE: Waster Water Concrete Bottom Slab Design
You can place them orthoganally (#5's @ 12 inches EW). But that makes the laps at the CJ's a pain. Or you can place them radially and circumferentially. The circumferential bars are easy. But the radial bars need to have their number and length adjusted to keep the spacing reasonable. Or you can chicken out and just define a maximum and minimum spacing.
RE: Waster Water Concrete Bottom Slab Design
Thanks. I am a chicken.