Research on Performance Optimization and Vulnerability Assessment of Tension Isolation Bearings for Bridges in Near-Fault Zones: A State-of-the-Art Review

This review offers a comprehensive analysis of the mechanical behavior and evolving design strategies of bridge bearings subjected to vertical seismic loading. Existing studies underscored that intense vertical ground motions—particularly those with high peak accelerations and rich frequency content—can provoke separation and subsequent impact between girders and bearings. Such interactions are especially harmful due to the inherently limited tensile resistance of conventional bearing systems. To evaluate vertical seismic performance, two core parameters are emphasized: tensile capacity and controlled energy dissipation. In recent years, the concept of tensile-resistant seismic design has garnered growing interest. By integrating high-strength steel cables, shape memory alloys (SMA), and advanced elastomeric materials, researchers have developed novel mechanisms that enhance the vertical resilience of bearings. This review synthesizes current understanding of near-fault seismic phenomena, recent advancements in bearing technology, and prospective research directions, thereby offering theoretical insight for optimal bearing selection and design, and contributing to the refinement of relevant engineering codes and standards.