Dear all:
In ASME B31,a word as following:If calculation of monments due to earthquake is required,use only one-half the earthquake monment range.
So if we use CAESAR,how can we consider up word?Or have CAESAR considered this?
If not,maybe we should use SUS+0.5*U as static earthquake stress case?But how can we do in dynamic earthquake case ?

Hi Twing. Please clarify in which code/para # is "the word" mentioned?

In ASME B31.1 Para104.8.2,page 27

my opinion:

earthquake is bidirectional,so consider 1/2 the earthquake monment range. I don't think to +0.5*U is right. Remember what "range" means.

happy spring festival!

Thanks your kind reply,whm.
But refer to what "range" means,I regard it as swing,as A=B*sin(Ct),"t"is time,so "B" is the range.your means that the range should be double B.

yes, i do think that "range" means double B. "B" is the amplitude. The amplitude of a sinusoid is the distance from its axis to a high point or a low point, but when it come to range, it means 2*B.

I got your means,thanks whm.
As your means,if our earthquake monment result is -200N.m to +200N.m,we can use 200N.m to calculate pipe stress.But another choice is -100N.m to +100N.m as one-half monment range,why not use 100N.m to calculate pipe stress?And why not define one-half the WIND monment range in ASME B31.1?
we use seismic peak acceleration as our input data,not average acceleration,so the 200N.m is base on movement by peak acceleration,so it's double to monment due to actual movement,so the result is too conservative.This is only my means,I sent you a massege,we can discuss this by email more detail.