Today is acche din (Good day) for us - seismic stress analysts in India as just an hour ago we experienced a seismic event in north east side of India!

Jokes apart, we pay scant notice to the excellent seismic code we have since 2002 in India!

In it due to height, amplification of seismic acceleration is there, which we are not following in non-nuclear fields in India. Here, we are considering loads & stresses due to earthquake 50% lesser than required, sometimes.

Say, for a coker overhead piping, seismic acceleration is considered same as the ground acceleration in static seismic analysis.

From forum members I wish to know how many of us consider this acceleration due to hight in seismic analysis in reality!

regards,
sam

I would say it's even more complicated with piping that connects different structures that will sway at their individual natural frequencies, and thus you "should" analyze them at opposing extremes.

In offshore practice, it's usually covered by the most extreme acceleration by common practice.
Until recently, I have not been required to consider flexibility of the structure itself exerting forces onto the pipe.

Yes; you are right regarding piping supported by two or more independent structures differential sway which is captured in seismic anchor movement SAM analysis.

But, I was talking about enveloped floor response of pipe support which is not considered when we take the ground acceleration as seismic acceleration input in static seismic analysis.

regards,
sam

To clarify, "yes," it is commonplace to account for height in offshore, but primarily by applying the worst-case acceleration across the board. This old-school assumption works on the premise that the entire offshore structure acts as a rigid body.

It's not until recently have I seen that individual supports being deflected at different rates as a function of facility coordinates, but accounting for height in a much more specific manner.

Otherwise, I personally don't see much in the way of seismic analysis, as my work is not in earthquake prone areas.