Seismic performance of benchmark highway bridge installed with piezoelectric friction dampers

Dynamic response of the benchmark highway bridge installed with semi-active piezoelectric friction dampers (PFDs) is investigated under six bidirectional earthquake ground motions. PFD utilises the response of the structure to develop control actions by adjusting frictional damping characteristics of the system. Conventional friction dampers abruptly fluctuate between stick-slip states. On the other hand, PFDs change the friction force continuously and smoothly. The study is based on the simplified lumped mass finite-element model of the 91/5 highway bridge, located in Southern California. The parameters affecting the performance of PFDs are gain factors, coefficient of friction and the preload on damper. Exhaustive studies are carried out to determine the most optimum values of these parameters. Eight dampers are installed at each deck-end and abutment junction (phase I). Additional four dampers are installed at the centre (phase II), at the junction of bent beam and piers of the bridge. In each case, the response of the bridge is compared with the corresponding uncontrolled case and that controlled by the alternate sample semi-active control strategy, using magnetorheological (MR) dampers. It is concluded that with the installation of PFDs, the seismic response of the bridge under near-fault motions can be controlled significantly. The PFDs are quite effective in reducing the peak response quantities of the bridge to a level comparable to or superior to that of the MR dampers.