Numerical study on seismic performance of a novel multi-level aseismic highway bridge with cable-sliding friction aseismic bearings and dissipative controlled rocking piers

Previous research mainly focused on enhancing the seismic performance of highway bridges by merely improving either piers or bearings, which may induce a high expense and a larger seismic demand of other structural members. To improve the bridge performance without over enhancements on single components, this study aims to propose a novel multi-level aseismic bridge system (MLABS) composed of cable-sliding friction aseismic bearings (CSFABs) and dissipative controlled rocking (DCR) piers. CSFAB, comprising a sliding bearing and restrainers, has the ability to reduce the pier demand and avoid bearing unseating. In addition, the use of DCR piers can enhance the pier capacity and mitigate the pier damage. Numerical analyses of the novel system are conducted under earthquakes with the designed and incremental peak ground accelerations (PGAs). The responses are compared with two single-level aseismic bridge systems (SLABSs) with ductile or DCR piers, and an unimproved MLABS with CSFABs and ductile piers. The results show that if not considering pounding, the novel system can effectively decrease the damage level and fragility, thus is capable of retaining in a low damage state and maintaining the bridge function under the stronger seismic inputs. Since the pounding effect may change the vulnerable components, the performance of the novel MLABS is not obviously superior to that of the unimproved MLABS, but is still much better compared with SLABSs.