Abstract: To promote the application of precast segmental piers in middle and high intensity seismic region, a partially assembled bridge pier consisting of a cast-in-place section at the pier bottom and a prefabricated section at the pier body, connected by unbonded prestressed steel bars, was proposed. A fiber element model was established to accurately simulate the stress characteristics of this type of bridge pier joint, and pseudo static hysteresis tests were conducted. The accuracy of the proposed model was verified through the test results. Then two sets of comparative experiments were designed by using the fibre element model to study and analyze the effects of two design parameters, namely the length of the cast-in-place section and the reinforcement ratio, on the seismic performance of partially assembled bridge piers. The results show that the horizontal ultimate load, residual displacement and energy dissipation of partially assembled piers increase with the increase of the length of cast-in-place segment. As the longitudinal reinforcement ratio increases, the horizontal ultimate load of the bridge pier gradually increases, while the residual displacement and energy dissipation of bridge pier decrease. When the reinforcement ratio reaches 1.48%, the horizontal ultimate load increases to a threshold and tends to be stable, and the residual displacement and energy dissipation capacity also tend to be stable.

Key words: bridge engineering; partially assembled piers; fibre element model; quasi-static test; parameter analysis

摘要： 为了推广预制装配式桥墩在中高烈度地震区的应用，提出了一种由墩底现浇段与墩身预制段组成，无粘结预应力筋连接的部分装配式桥墩。建立了能够准确模拟该类桥墩接缝受力特点的纤维单元模型并进行了拟静力滞回试验，通过试验结果验证了模型的准确性。然后利用纤维单元模型设计了2组对比试验，研究分析了部分装配式桥墩现浇段长度和配筋率2个设计参数对桥墩抗震性能的影响。研究表明：部分装配式桥墩的水平极限荷载、残余位移和耗能能力随着现浇段长度的增大而增大。随着纵向配筋率的增加，桥墩的水平极限荷载逐渐增加，同时残余位移和耗能能力减小，当配筋率达到1.48%时，水平极限荷载增大到一个阈值趋于稳定，同时残余位移和耗能能力也趋于稳定。

关键词: 桥梁工程；部分装配式桥墩；纤维单元模型；拟静力试验；参数分析