Settlement of the tank under seismic condition

[B.L.Smith]

Dear Sirs,

I'm performing stress analysis for a tank. Civil department sent me an email about settlement of the tank for different conditions. He specified settlement under operating, hydro test and seismic condition. In most documents settlement at operating condition are considered for stress analysis. Now I'm not sure about using settlement of the tank under seismic condition. Is it important to consider this settlement for stress analysis or operating settlement is enough?

 

[DSB123]

So you do not mind if the tank ruptures during a seismic event causing settlement then??

 

[B.L.Smith]

Dear DSB123,

No, the settlement is do to tank movement under seismic

 

[saplanti]

Is the seismic settlement cyclic? I do not expect it is. So the maximum (or both) displacement of operating condition and seismic will be added to the operating conditions, and will be considered in the thermal load cases for code evaluation.

 

[DSB123]

BradSmith,
So you have answered your own question. You need to consider the specified settlement of the tank under seismic conditions.

 

[B.L.Smith]

Dear friends
tnx for your reply. Do you agree with below load cases:

(1) WW+HP HYD
(2) W+D1+T1+P1 OPE(Operating Settlement And operating Temperature)
(3) W+D1+T2+P1 OPE(Operating Settlement And Design Temperature)
(4) W+P1 SUS
(5) W+D2+T1+P1+U1 OPE(D2: Operating+Seismic Settlement)
(6) W+D2+T1+P1-U1 OPE(D2: Operating+Seismic Settlement)
(7) W+D2+T1+P1+U2 OPE(D2: Operating+Seismic Settlement)
(8) W+D2+T1+P1-U2 OPE(D2: Operating+Seismic Settlement)
(9) L2-L4 EXP
(10) L3-L4 EXP
(11) L5-L2 OCC
(12) L6-L2 OCC
(13) L7-L2 OCC
(14) L8-L2 OCC
(15) L4+L11 OCC
(16) L4+L12 OCC
(17) L4+L13 OCC
(18) L4+L14 OCC