seismic forces on ground supported tanks

[sbk1956]

Does anyone know how to calculate the impulsive weight Wi per ASCE paragraph 15.7.6.1. Is it just the weight. If so, why don't they say so?. How do you calculate Wc?

 

[JedClampett]

This is an expression borrowed from AWWA D100, Standard for Welded Steel Tanks for Water Storage. You need to get a copy of that for the method of calculation.
API probably has something similar, but I don't have that available.

 

[Sawbux]

It it's a small tank, use entire contents for both impulsive and convective.

If it's a substantial size tank, you'll need to get one of the reference docs listed in ASCE 7-05, chapter 23 for the type of tank it is.

I am most familiar with concrete tanks, so use ACI 350.3. The factors vary with size of tank and whether it is rectangular or circular. They have charts where you can determine the factors or you can solve an equation to determine. Main parameter you need is the length or diameter to Height of liquid ratio.