Safety and constructability evaluation of a sky bridge system using lead rubber bearings

This study investigated the design, seismic performance, and constructability of lead rubber bearing (LRB) systems for two skybridges connecting three high-rise towers. The target structure is a residential complex with three towers approximately 200 m high and two skybridges installed at the 17th floor between adjacent towers. To accommodate relative lateral and torsional displacements caused by differences in tower dynamic characteristics during earthquakes, multidirectional LRBs were installed at the skybridge supports. Linear elastic analyses were conducted to determine design axial forces and displacement demands, followed by nonlinear time-history analyses using seven spectrum-compatible ground motions to evaluate seismic responses. The results showed that maximum horizontal and relative displacements at all isolation interfaces remained within the design allowable limit of 150 mm. Full-scale LRBs manufactured according to the design specifications were tested under pure compression and combined compression – shear cyclic loading following ISO 22762–1. The test results confirmed satisfactory vertical stiffness, effective horizontal stiffness, and energy dissipation capacity. Overall, the proposed LRB system demonstrated reliable seismic performance and practical applicability for skybridges in high-rise building complexes.