Settlement of Water Tank 1

[moe333]

I'm trying to estimate the settlement of a steel water tank to be constructed over medium dense sany alluvium, water table at about 13 feet. The tank will about 55 foot diameter and 23 feet high, and will be set on a concrete ringwall foundation. I have a CPT profile to 50 feet. I don't think settlements will be excessive for these conditions, but want to get an estimate to confirm this.

I am considering using the Schmertman (70, 78) method of estimating footing settlement on sand with the strain influence approach and elastic theory, but this method is for a rigid footing, whereas the tank should be flexible.

Another simplified method I'm considering is by Myerhoff (65), modified by Duncan and Buchignani (76). This is a simple formula which uses blow counts and bearing pressure.

Any suggestions are appreciated.

 

[JoeTank]

BigH,
Rumor has that a lot of tanks you may be referring to may have "bearing plates' under the sketch plate. Is that true from your experience?

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[am]

Big-H

Thank you for your suggestion. Soil is well compacted granular soil, Ø is about 30°. I did not run any numbers yet, but looking at the pump foundation indicates they are quite substantial and will provide good damping. However I do not have the pump details yet and can not confirm my views with calculation. However I am trying to source the Soil dynamics book as per your suggestion.

Regards

AM

 

[BigH]

Steve - I do believe they are "strengthened" - they would almost have to be to take the edge bending stresses. Will check out a couple of our old site people who actually were on site. -