Sensitivity factor analysis of seismic performance of seismically isolated girder bridges during the operation period

The seismic performance of isolated girder bridges is accurately investigated and addressed by considering the theoretical foundation of seismic isolation, taking into account the operational period’s service state and changes in relevant performance indicators of vulnerable components. The analysis encompasses a comprehensive parameter analysis of seismic performance during the operational period, utilizing finite element analysis software, which involves comparing and analyzing structural deflections, deformation performance, and damage performance of seismically isolated girder bridges under varying parameters. The research findings indicate that, in terms of evaluating the damage state of the member, the displacement of the girder end of the main girder is primarily influenced by the interface friction coefficient of the isolation device, followed by the post-yield stiffness of the bearing. Conversely, abutment lateral stiffness has a relatively minor influence. Moreover, it is observed that the mechanical properties of the bearing (friction coefficient and post-yield stiffness) exert a significant impact on the structural seismic response. Therefore, more attention should be paid to the functional condition and the variation of mechanical performance parameters of the seismic isolation bearing during the operational phase.