Seismic Performance of Self-Centering UHPC Retainers Applied to Medium-Small Span Concrete Bridges

Seismic resistant retainer is an important component for seismic design of the medium‐small span bridges. However, it’s difficult for the bridge engineers to design a reasonable transverse retainer due to deficiency of design detail in most of current seismic design specifications. Therefore, this paper proposed a prestressed prefabricated concrete retainer that utilize the ultra‐high performance concrete (UHPC). Firstly, the structural characteristics and the seismic design method of the new proposed retainer is illustrated. The OpenSEES model of the case‐study bridge were simulated by considering three different types of seismic resistant retainers. A total of ten high intensity ground motions were selected to conduct the nonlinear time history analysis (NTHA). Subsequently, to investigate the seismic performance of the proposed UHPC retainer, this paper performs the comparative study of seismic responses for different bridge components. It is concluded that, the proposed retainer can provide excellent displacement capacity and help to reduce the seismic damage of bridge piers significantly. In addition, the new retainer has strong ability to keep self‐centering to help the bridge reducing the residual displacement of superstructure under strong seismic events. The proposed UHPC retainer is applicable to the rapid prestressed prefabricated construction process and has a clear load transfer mode under earthquake actions. Therefore, it is a good candidate to the multi‐level performance‐based seismic design of the medium‐small span bridges.