definition of "ground supported" storage tank per AWWA D100? 2

[EngineerofSteel]

I designed a water storage tank for a milking parlor.

It is vertical: diameter= 11ft 9in
height = 26 ft

I used ASCE7-05 Section 15.7.6.1 "Ground Supported Storage Tanks for Liquids"

part a says "The base shear and overturning moment calculated as if thank and the entire contents area a rigid mass system per Section 15.4.2 of this standard."

This is easy for me, and, according to some articles I read, slightly conservative over the more complicated sloshing design process.

However, the county reviewer (not an engineer of any kind despite his signature block) is insisting that AWWA D100 be used.

I am only designing the foundation in this project- the tank is being moved from one location to this new site. So, AWWA D100, Section 13.2.11 allows ASCE7 design procedure, with some exceptions, which I have met.

The county agent is insisting that the D100 procedure "with slosh" be used.

I completely disagree.

Who is correct here?

 

[Ron]

If you meet the exceptions for using ASCE 7 under D100, then you meet D100 for your tank.

The D100 provisions primarily apply to seismic design of the shell, with less effect on the foundation.

 

[JStephen]

The primary effect of including sloshing when analyzing a larger tanks is a reduction in the overall seismic loading, as the longer period of the sloshing wave gives reduced coefficients. For a small tank like yours, this might be a wash. Consideration of sloshing also allows you to calculate the recommended freeboard.

If you have a copy of D100-05, it doesn't take too long to work through the seismic design once you're familiar with it, and it might be easier to do so than to persuade the reviewer otherwise.

 

[EngineerofSteel]

JS-

I do have D100-05. However, the point is, this guy is wrong all the time.

He once insisted there is "no such thing" as XS pipe. Apparently, he had Strucalc v. 7, which does not show sections for XS pipe.

So, I have a need to maintain the trend of me always being correct.

If I yield to him... I expect it will encourage him to continue in ridiculous challenges, such as requiring that every anchor bolt in every project be designed according to ACI 318 appendix D.

The tank is flush water for the access ramp leading to a milking pit. It is category I importance, and therefore does not require any freeboard (Table 29 in D100).

Thanks for the answers. They are the kind of responses I am looking for... Mostly I just want agree/disagree, with reasoning for disagreement.

Thanks!

 

[msquared48]

So... XXS does not exist either?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[EngineerofSteel]

haha!

NO. XXS pipe does not exist either, apparently.

DD