Elevated Storage Tank
Elevated Storage Tank
(OP)
I am doing an analysis of an elevated chemical storage tank. Should the liquid be defined as a live load or dead load? Secondly I need some insight into the seismic design of the elevated tank due to sloshing of liquid inside (ASCE chapter/section reference would help). Thanks






RE: Elevated Storage Tank
RE: Elevated Storage Tank
RE: Elevated Storage Tank
Liquid in containers are Fluid Load "F".
The procedure is same as any tank regardless if is on ground or elevated.
Draw a pic with dimension and information if need more assiatance
RE: Elevated Storage Tank
RE: Elevated Storage Tank
RE: Elevated Storage Tank
Hope this helps!!
RE: Elevated Storage Tank
RE: Elevated Storage Tank
And, for elevated water tanks, AWWA D100 does not consider sloshing effects. I think there are two issues there. One is, that ground storage tanks are vertical cylinders, there's been a lot of work done on dynamic effects of that shape, and so it's easily codified. But elevated tanks are a variety of spherical/cylindrical/conical/toroidal shapes, and combinations thereof, and so it's not as easy to work with. The second thing is that on a larger ground storage tank, consideration of sloshing effects leads to a reduction in the forces, not an increase, so neglecting sloshing is conservative in those cases.
RE: Elevated Storage Tank
The fluid level can be assumed empty or full. Pretty easy.
But, the changing loads hit you four places:
The tank-to-support welds and their fasteners.
The tank-support stress levels. (middle of the post stresses)
The tank-support-to-base-plate loads,
then the base-plate-to-concrete pads loads, and the subsequent pads-to-dirt loads underneath the concrete)
A dead load (in civil terms) is easier to predict than a live load, seismic loads at all four places are the hardest of all. So, the difference in codes tends to give the biggest margins to the hardest-to-predict stresses. That's the reason for the difference in terms for the tanks - how well can somebody predict what is going to happen in worse-case conditions.
RE: Elevated Storage Tank