Water and wastewater steel tanks under multiple earthquakes

This study focuses on the inelastic response of water and wastewater steel tanks under multiple earthquakes. The main innovation of the proposed study has to do with the quantification of the seismic sequence effect into steel tanks, a phenomenon which has not been studied in the past. Firstly, this paper considers real seismic sequences that have been recorded during a short period of time (up to three days), by the same station, in the same direction, and almost at the same fault distance. In these cases, due to lack of time, any rehabilitation action is difficult or impractical and the multiplicity of earthquakes can lead to important damage accumulation. Furthermore, artificial seismic sequences are also examined where they have been generated by a rational and random combination of real single events. It is found that due to the multiple earthquakes effect, it seems to be unreliable to consider only single earthquake records in steel tank design process, since this long-established assumption leads to underestimated demands in terms of bearing capacity and deformation.