腐蚀近海桥墩十字形双向拟静力试验及损伤分析

CROSS-SHAPED BIDIRECTIONAL QUASI-STATIC TESTS AND DAMAGE ANALYSIS OF CORRODED COASTAL BRIDGE PIERS

为研究十字形双向加载作用下腐蚀近海桥墩的损伤演化,设计了2个尺寸及配筋相同的钢筋混凝土(reinforced concrete,RC)桥墩试件,对其中之一开展了电化学腐蚀试验,随后对2个试件进行了十字形双向拟静力试验。基于实测数据,分析了腐蚀作用对墩柱滞回特性及刚度退化的影响,基于试验现象,及考虑腐蚀和加载路径的改进Park-Ang双参数模型,研究了墩柱损伤演化过程。结果表明:与未腐蚀墩柱相比,腐蚀率为24.15%的墩柱的极限承载力降低达28.74%,累积耗能降低了55.74%;腐蚀作用会明显加速墩柱的双向地震损伤进程;变形对未腐蚀及腐蚀墩柱的双参数损伤指标贡献皆随着位移的增大先减小后缓慢增大;该文改进的Park-Ang模型,结合牛荻涛等的损伤指标范围,能合理量化墩柱损伤状态,可为腐蚀近海桥墩的双向地震损伤分析提供参考依据。

To study the damage evolution of corroded coastal bridge piers under cross-shaped bidirectional loads,two reinforced concrete(RC)pier specimens with the same dimensions and reinforcement were designed,and one of them was electrochemically corroded.The two specimens were tested quasi-statically under cross-shaped bidirectional loads.The influence of corrosion on the hysteretic behavior and stiffness degradation of the piers was analyzed.Based on the test phenomena and an improved Park-Ang dual-parameter damage model which considers the corrosion and loading path,the damage evolution processes of the piers were studied.The results show that,compared with the uncorroded pier,the ultimate strength of the pier with a corrosion rate of 24.15%was reduced by 28.74%and the cumulative energy consumption was reduced by 55.74%.The corrosion obviously accelerated the bidirectional seismic damage process of the pier.The contribution of the deformation to the dual-parameter damage indexes of the uncorroded and corroded piers first decreased and then increased slowly with the increase of the displacement.Combined with the damage index range proposed by Niu and others,the improved Park-Ang model can reasonably quantify the damage state of the piers and provides reference for the bidirectional seismic damage analysis of corroded coastal piers.