This study evaluates the performance of a steel water
tank under 2 different types of ground motions: pulse-like and
non-pulse-like ground motions. The main focus was based on the
contribution of SSI effects on the seismic behaviour of these
structures. Most of the international design codes treat SSI as
beneficial effects for the majority of the structures by basically
assuming that the structure is becoming more flexible and its
damping is going to increase. This study is going to show that
this is not always the case. It is also going to show the big
differences between pulse and non-pulse-like ground motions
with regards to the seismic performance of the tank.
The modelling of the tanks was based on the well established
assumption that the liquid can be represented by 2 masses:
impulsive (which treats the liquid as a stiff mass moving along
with the tank wall), and convective (which takes into account the
sloshing nature of the liquid and moves in an out of phase way
compared with the rest of the tank).