Jk. Sinha et Rik. Moorthy, Combined experimental and analytical method for a realistic seismic qualification of equipment, NUCL ENG DE, 195(3), 2000, pp. 331-338
The seismic qualification of equipment/structures are, in general, carried
out either exclusively by analysis or exclusively by testing using a shake
table. The analytical methods have the risk of the model not being a true r
eflection of the structure unless very elaborate modelling techniques are u
sed. Even with an elaborate model there are many idealisations made which m
ay not actually be realised in practice. The shake-table testing, avoids th
e modelling deviations to a large extent, but is also not without drawbacks
. The important ones are the cost and the availability of a shake table of
the required size and capacity. The shake-table testing is also carried out
on the isolated equipment without the piping/structural connections from o
ther components. The present paper suggests a combined experimental and ana
lytical method on the 'as installed' equipment as an attractive alternative
which overcomes the above drawbacks. In contrast to the existing practice
of using the experimental results just to validate the analytical model, th
e suggested method uses the experimentally obtained dynamic characteristics
of the 'as installed' equipment to obtain the response to the design seism
ic load. The paper brings out through an example of a simple storage tank w
hich is too heavy for a shake table, the large deviations in its actual beh
aviour vis-g-vis an idealised analytical model. (C) 2000 Elsevier Science S
.A. All rights reserved.