氯离子侵蚀效应对RC桥墩抗震性能的影响
Influence of Chloride Ion Corrosion on Seismic Performance of ？？Reinforced Concrete Piers

为研究混凝土桥梁结构在服役期内由于环境氯离子侵蚀效应引起钢筋、混凝土锈蚀退化等导致结构抗震性能退化的规律，以某多跨钢筋混凝土连续梁桥为例，采用OpenSees软件建立非线性动力分析模型，根据已有研究成果并基于概率方法研究了墩柱截面主筋和箍筋锈蚀的开始时间和锈蚀率大小，进而建立了钢筋的直径及屈服强度退化模型；针对考虑纵筋锈蚀、考虑箍筋锈蚀、同时考虑纵筋和箍筋锈蚀3种情况，分别分析了材料退化对桥墩抗震性能的影响。结果表明：同等条件下箍筋锈蚀比纵筋锈蚀更早；随着时间的推移，氯离子侵蚀效应会导致桥墩抗震能力下降，结构的抗震需求明显增加；与以往只考虑纵筋锈蚀的情况相比，同时考虑箍筋和纵筋锈蚀时桥墩抗震性能退化更严重。
In order to study the deterioration law of seismic performance for concrete bridges which was caused by chloride ion corrosion on steel and concrete during the bridge’s service life, a multi-span reinforced concrete (RC) continuous girder bridge was taken as an example. The nonlinear dynamic analysis model was established by OpenSees software. Based on the previous researches, the probabilistic analysis method was applied to investigate the initial corrosion time and corrosion rate of the main reinforcement of pier column section and stirrup. Then the deterioration models of the diameter and yield strength of steel were established. Three typical analysis cases, consisting of longitudinal reinforcement corrosion, stirrup corrosion and the combination corrosion of longitudinal reinforcement and stirrup, were investigated to study the effects of material deterioration on the seismic performance of RC piers. The results show that the initial corrosion time of stirrups is earlier than that of longitudinal reinforcements under the same conditions. The chloride ion corrosion effect can cause the deterioration of seismic capacity for the RC piers as time goes on, and the seismic demands will increase obviously. Compared with only considering the corrosion situation of longitudinal reinforcement in the past, the deterioration of seismic performance is more serious when the stirrups and longitudinal reinforcement corrosion are both considered