AWWA D-100-11 (Eqn 13-18) 3

[starcasm]

Hello everyone,

I am developing the seismic forces on a ground-supported, mechanically anchored water storage tank. I am currently at Section 13.2.9.2 where I calculate the impulse design acceleration (Ai) and the convective design acceleration (Ac). I noticed that equation 13-18 for (Ac) asks for (Ri) which is the same response modification factor for the impulse design. The section even goes on the describe (Rc) but it is not in either equation.

I feel that equation 13-18 is intended to have (Rc) in the denominator. I couldn't find an errata for the AWWA D-100-11 and I couldn't find any existing conversations about this in my searches.

Does this look like a typo? If not, could you let me know why. Thank you in advance for your time.

(edited: original post incorrectly had the equation as 13-8)

 

[Teguci]

Try comparing your results from AWWA equations to the results from ASCE 7 15.7.6. It might help if there is a clear match between the 2.

 

[starcasm]

ASCE 7-10 15.7.6 is similar but equation the ASCE equation 15.7-6 doesn't even have an (R) in the denominator. I think this is why there is Section 15.7.7.1 for ASCE 7-10 which directs me to AWWA D-100 specifically for what I am doing. Thank you.

 

[enginerding]

I think you are talking about Equation 13-18. I would note that the same equation in AWWA D100-05 contains Rc. I think it is fair to assume there is a typo in the 11 version.

 

[JStephen]

I have assumed it was a typo as well. If I'm wrong, I'm overestimating seismic forces.

 

[starcasm]

Woops! That is correct. I was referring to equation 13-18. Thank for you for the heads up.

 

[starcasm]

I contacted AWWA directly and they confirmed that there is a typo is equation 13-18. Ri should be Rc. I edited the original post to reflect the correct equation for searching purposes. Thanks everyone.