为了揭示长期服役下材料劣化对高墩刚构桥抗震性能的影响,基于钢筋和混凝土的时变劣化模型,按照能力/需 求(C/D)的抗震性能评估流程,针对西部山区某典型双薄壁髙墩刚构桥,研究了桥梁在非线性时程分析下的地震响应、抗震能 力和C/D的时变规律.研究表明:随着服役年限的增长,高墩的地震响应和抗震能力都在不断下降;地震响应在前40年间降 幅较大,此后趋缓,关键截面的弯矩下降14. 87％～21. 44％,剪力下降4. 77％～13. 59％;在抗震能力方面,抗弯能力下降最 大,降幅达23. 70％～25. 07％,且降幅主要集中在前40年,抗剪次之,降幅在10. 60％左右,延性基本保持不变;关键截面抗弯 C/D在前40年显著下降,此后几乎不变,而抗剪C/D和延性C/D的变化幅度总体较小.在对高墩刚构桥进行抗震评估时应 考虑材料劣化的不利影响.%With the aim to reveal the effect of material deterioration on the seismic performance of rigid frame bridge with high piers after long-term service, a seismic performance evaluation process based on capacity to demand ratio (C/D ratio) is proposed according to the time-dependent deterioration models of reinforcement and concrete. In the background of a typical rigid frame bridge with high double-walled piers located in western China, nonlinear time history method is applied to investigate the time-dependent characteristics of seismic response, seismic capacity and the C/D ratios of the bridge. The results show that the seismic demand and capacity of the high piers decline during their service life. The decrease of the seismic demand is sharp in the first 40 years and then tends to slow down. The moment demands of critical sections decrease by 14. 87％～21. 44％ while the shear demands decrease by 4. 77％～13. 59％. The reduction of moment capacity of critical sections is most significant, with a decrease magnitude of 23. 70％～25. 07％ mainly occurring in the first 40 years. The shear capacity reduction of critical sections is around 10. 60％, and the ductility of the piers almost remains unchanged. The C/D ratios of critical sections significantly decrease in the first 40 years, and then remain stable. The C/D ratios of shear and ductility vary in a very small range, and therefore, it is important to take into account of the unfavorable effect of material deterioration when assessing the seismic performance of rigid frame bridges with high piers.
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