氯离子侵蚀对RC与UHPC墩抗震性能影响对比研究

Comparative Study on the Influence of Chloride Ion Corrosion on Seismic Performance of RC and UHPC Piers

以一座海洋环境中的三跨连续梁为例,首先研究了氯离子侵蚀对RC与UHPC桥墩的钢筋初始锈蚀和保护层锈胀时间的影响规律,选取100条地震波,采用OpenSees建模分析各时间节点的桥梁地震需求,针对海工桥梁定义新的耐久性损伤状态,建立RC与UHPC桥墩的时变地震易损性曲线,对抗震性能进行评估比较。结果表明:UHPC墩的钢筋初始锈蚀与保护层锈胀时间明显晚于RC墩;氯离子侵蚀会导致RC与UHPC桥墩的水平承载力下降,且RC墩下降幅度相对较大;UHPC墩的耐久性损伤概率明显小于RC墩;常用损伤状态下的两种桥墩损伤概率均随时间增长而增加,且RC墩的损伤概率和增幅均高于UHPC墩。

Take a three span continuous beam in an ocean environment as an example.The influence of chloride ion erosion on the initial corrosion time and rust expansion time of protective layer of RC and UHPC piers were studied.100 seismic waves were selected from PEER seismic database.Seismic requirements of bridges at diffrernt time were analysed by OpenSEES.Define new durability damage state for marine bridges.Establish time-dependent seismic fragility curves of pier for different damage states.Evaluate and compare the seismic performance of RC and UHPC piers.It is concluded that The time of initial corrosion of reinforcement and rust expansion of protective layer of UHPC pier is obviously later than that of RC pier;chloride corrosion will reduce the horizontal bearing capacity of RC and UHPC piers,and the decrease range of RC pier is relatively large;under the same conditions,the durability damage probability of UHPC pier is obviously smaller than that of RC pier;with the increase of service time,the damage probability of the two kind piers in common damage states increases with time,and the damage probability and increases of RC pier are higer than that of UHPC pier.