Passive-hybrid system of base-isolated bridge with tuned mass absorbers

Abstract

Nowadays, improved versions of earthquake response modification devices are being introduced to maximise efficacy in dynamic vibration abatement in structures. Here, hybrid system has been proposed to be used for earthquake response modification of bridges by combined use of two passive devices: base isolation systems and tuned mass absorbers. The efficacy of the passive-hybrid system is verified by implementing it in a reinforced concrete (RC) bridge subjected to earthquake ground motions. The RC bridge has three continuous spans and supported on two piers in the middle and abutments at the ends. In the developed numerical model, the flexibility of the founding soil has been accounted for. The numerical model is analysed to determine the dynamic response of the bridge equipped with the passive-hybrid system and a comparison is made with the dynamic response determined without installing such systems. Primarily, it is concluded that the passive-hybrid system exhibits significantly improved performance in dynamic response abatement of the bridge. Nonetheless, the founding soil flexibility at the bottom end of the piers influences the efficacy of the tuned mass absorbers provided at the mid-span of the bridge deck because it affects the modal response quantities.