An innovative sliding-controllable laminated rubber bearing for enhancing seismic performance of highway bridges

Economical laminated rubber bearings have been widely utilized in highway bridges for their exceptional performance under service conditions. These bearings effectively mitigate seismic responses during earthquakes through shear deformation or sliding, contingent upon their bonding methods, whether bonded or unbonded. Nevertheless, past seismic events have underscored vulnerabilities, with unbonded laminated rubber bearings susceptible to excessive displacement and bonded bearings prone to fracture during large earthquakes. To address these seismic deficiencies and improve bridge seismic performance, a novel controllable sliding laminated rubber bearing (SC-LRB) is proposed in this study. The SC-LRB seamlessly integrates the shear-deforming behavior of bonded laminated rubber bearings (B-LRB) with the frictional sliding behavior of unbonded bearings (U-LRB). A quasi-static experiment was initially conducted to investigate the cyclic behaviors of the SC-LRB, leading to the development and calibration of the numerical model for the bearing. Subsequent nonlinear time history analyses were carried out to evaluate the influence of SC-LRBs on the seismic performance of bridges. Results indicate that, with its three-stage working mechanism (pre-sliding, sliding, and post-sliding), the SC-LRB exhibits a friction-shear collaborative behavior, effectively balancing the energy dissipation and recentering capacities of the bearing during earthquakes. Bridges equipped with the SC-LRB demonstrate an ability to maintain balance between controlling bearing displacements and isolating pier seismic demands. The proposed SC-LRB presents promising potential for enhancing the seismic resilience of highway bridges.