多环境腐蚀作用下钢筋混凝土梁疲劳损伤模型

摘要

Such subway and light rail as urban rail transit,concrete structures often service in the coupling ac-tions of stray current,chloride ions and fatigue load.According to the fatigue behaviors of the reinforced con-crete (RC)beams,the four-point flexure fatigue experimental investigation of the RC beams under multi-envi-ronment corrosion of stray current (30V)and chloride ions (3.5%)was carried out.The nonlinear fatigue life prediction and fatigue accumulation damage models used for the RC beams under the multi-environmental cor-rosion were established based on the fatigue modulus degradation.The results show as follows:The multi-en-vironmental corrosion of stray current and chloride ions has important influence on the fatigue damage of RC beams and the influence is greater with fatigue loads increase;the damage process can be divided into initial damage stage,accumulation damage stage and failure stage;the failure occurs suddenly without any signs be-forehand;the nonlinear fatigue damage models can describe the damage development of the RC beams under the multi-environmental corrosion and the predictions are in good agreement with the experimental results.%地铁、轻轨等城市轨道交通混凝土结构常处在杂散电流、氯离子与疲劳荷载共同作用下服役。针对这种典型服役条件下钢筋混凝土疲劳损伤行为，开展了30 V杂散电流与3.5%氯离子多环境腐蚀作用下钢筋混凝土梁四点弯曲疲劳试验研究。基于弯曲疲劳模量退化，建立用于这种典型服役条件下钢筋混凝土梁的非线性疲劳寿命预测和疲劳累积损伤模型。研究结果表明：杂散电流和氯离子多环境腐蚀对钢筋混凝土梁疲劳损伤影响显著，且疲劳荷载越大影响越大。损伤过程分初始损伤、累积损伤和失效破坏等3个阶段，破坏时无征兆。本文所建立的非线性疲劳损伤模型可描述这一损伤演化趋势，预测结果与实测值吻合较好。