Seismic performance of precast piers connected by grouted splice sleeve with Central-tenon enhancement: experimental validation and system-level fragility study

While precast piers are increasingly being utilized in low-to-medium seismicity regions, concerns have arisen regarding their seismic performance due to the discontinuity of concrete on both sides of the joint surface. In order to strengthen the connection of conventional grouted splice sleeves (GSS), it is proposed to interpose a grouted tenon at the interface of the precast pier segment, forming the so-called 'central-tenon-assisted grouted splice sleeve' (CT-GSS) connection. Through a quasi-static experimental campaign involving scaled bridge piers with both CT-GSS and GSS connections, it was found that the CT-GSS connection effectively enhanced lateral strength and ductility while reducing the residual drift of the precast pier. In connection with a real-life bridge implementing the proposed CT-GSS connection in China, a system-level model in consideration of various nonlinear behaviors of different components is established. Site-specific ground motions are selected through the multiple stripe analysis with limited scale factors following the conditional spectrum method. Based on four defined limit states, fragility curves are obtained at both the component level and system level. The results show that the use of the proposed connection could limit the possibility of damage occurrence.