The damage investigation of inelastic SDOF structure under the mainshock-aftershock sequence-type ground motions

Structures located in seismically active regions may be subjected to mainshock-aftershock sequence-type ground motions, which are characterized by the presence of strong aftershock ground motions after the mainshock and separated by short intervals of time. This manuscript investigates the damage of inelastic SDOF structure with four hysteretic models and three response demand parameters. The relative intensity of the aftershock ground motion to the mainshock ground motion is defined, denoted by PGA(as)/PGA(ms). The aftershock ground motions are scaled to have different levels of PGA(as)/PGA(ms). The results indicate that the effect of aftershock on ductility demand is slight for PGA(as)/PGA(ms) <= 0.5 and can be ignored in engineering practice. The aftershock ground motion has more significant influence on the normalized hysteretic energy and damage index than on ductility demand. The effect of aftershock ground motion with larger PGA(as)/PGA(ms) on the response demand is generally more obvious for non-degrading system than for degrading system. (c) 2014 Elsevier Ltd. All rights reserved.