Experimental Study on Seismic Performance of External Socket Precast Bridge Pier-Footing Connections for Rapid Postearthquake Replacement

Assembly of precast elements is a widely adopted technology for achieving accelerated bridge construction (ABC) owing to the increased construction speed and quality. Connection methods between precast structural members, if designed properly, can facilitate a convenient postearthquake replacement of damaged members and hence enable rapid function recovery of bridges. This study proposes a new precast bridge pier-footing connection using external sockets. The external sockets are prefabricated on the top of bridge footings and the precast piers can be directly inserted into the sockets with postgrouting. Quasi-static cyclic loading tests were conducted on four 1/4-scale pier-footing specimens, including three external socket pier specimens and a cast-in-place (CIP) specimen for comparison purposes. The experimental results show that the external sockets with normal design sizes are effective precast pier-footing connection methods, ensuring that plastic hinges are formed in the piers without damaging the external sockets and footings. Because of the shortened effective pier height, the socket piers show increased lateral stiffness and strength but decreased displacement capacity compared with the CIP pier. The measured peak horizontal forces for the precast socket pier specimens PCS-1, PCS-2, and PCS-3 are increased by 7.5%, 34.5%, and 51.4%, respectively. However, the ultimate displacements are reduced by 11.1%-22.0% compared with the CIP pier. The hysteretic energy dissipation of the socket piers is compared with that of the CIP pier, with a difference less than 20%. Postexperiment replacement of a tested precast pier was carried out, which demonstrates the feasibility of rapidly replacing damaged bridge piers when using the proposed external socket connections. A subsequent experiment reveals that the newly replaced pier specimen could show an equivalent seismic performance to the previous specimen. The maximum differences of the peak force and initial stiffness between the two piers are within 6.7%, and the difference of the dissipated energy is only 3.8%. The experimental results verified the effectiveness of the rapid replacement.