A Novel Frictional Sliding Shear Key for the Transverse Seismic Mitigation of Girder Bridges

Abstract

The concrete shear keys (CSK) are the conventional component in the girder bridges to restrain the seismic-induced excessive displacement in the transverse direction. However, the failure of the CSKs is often observed in strong earthquake events, which indicates the inadaptability of the CSKs in such extreme circumstances. This study proposes a novel frictional sliding shear key (FSSK) to improve the seismic performance of girder bridge especially under the earthquakes with high intensities. The configuration and the working mechanism are first introduced to derive the governing equations and the hysteretic models. A design method is proposed on the premise of the safety of the pier columns to determine the parameters of the FSSK. The mitigation effectiveness of the FSSK is investigated through a case study of a typical isolated bridge subjected to a suit of 80 ground motion records with 12 levels of seismic intensities. Results demonstrate that the lateral force and the energy-dissipating ability of the FSSK both increase dramatically with the increase of its lateral deformation, which implies the FSSK could play a more significant role under strong earthquakes. The numerical results of the case study denote that the FSSK can prominently reduce the bearing deformation of the bridge model under strong earthquakes, while the seismic responses of the pier could be enlarged. Besides, the combination of the FSSK and the CSK could further decrease the bearing deformation and only slightly increase the pier responses at high seismic intensities. The findings of this study are aimed at improving the transverse performance of the girder bridges under strong earthquake.