Uniform surcharge offset from tank wall
Uniform surcharge offset from tank wall
(OP)
I am looking for an equation for the lateral pressure from a uniform surcharge located several feet back from the wall of a buried tank. Everything I have considers a uniform surcharge set directly against the structure. If anyone can help me out or point me to a good reference which addresses this situation I would greatly appreciate it. Thanks in advance.





RE: Uniform surcharge offset from tank wall
h =(p/3)[arctan(x2y1/zRx2)-(x2y1z)/(x2^2+z^2)Rx2
arctan(x1y1/zRx1)+ (x1y1z)/(x1^2+z^2)Rz1
h = horizontal unit pressure at point on wall
p = surcharge unit loading
x1 = distance from wall to face of surcharge
x2 = distance from wall to back of surcharge
x12-x1 = width of surcharce normal to wall
y1 = lenght of surcharge
z = depth of point on wall
Rx1 = (x1^2+y1^2+z^2)^0.5
Rx2 = (x2^2+y1^2+z^2)^0.5
which is why we usually say screw it, take 1/3 the surcharge and apply it to the wall.
Best, Tincan
RE: Uniform surcharge offset from tank wall
I guess it wouldn't hurt to give a little background on my situation and what I am trying to accomplish. I have a rectangular concrete tank which was originally designed to be buried with the top of the tank at grade. Because of required piping elevations and gravity feed requirements the tank will need to be 5' lower than originally planned. In order to maintain the current configuration of the tank I was planning to locate a retaining wall around a portion of the perimeter to reduce the effect of the additional overburden. My dilema is finding out how far from the edge of the tank it needs to be to keep my tank walls at a resonable thickness. Just in case you were curious.
Thanks again for taking the time to type out the formula. I do appreciate it.
~ Waytsh
P.S. Do you have a good foundations reference that you would recommend?
RE: Uniform surcharge offset from tank wall
Best, Tincan
RE: Uniform surcharge offset from tank wall
RE: Uniform surcharge offset from tank wall
RE: Uniform surcharge offset from tank wall
Also, we normally figure that anything outside a 1:1 slope has little or no effect. From the bottom of the tank go up on a 1:1 for the placement of the retaining wall. Sketch this out and see how it plays.
Tincan
RE: Uniform surcharge offset from tank wall