在役钢管混凝土拱桥吊杆钢丝腐蚀疲劳损伤机理

Corrosion fatigue damage mechanism of steel wire of in-service concrete-filled steel tubular arch bridge boom

为了评估在役钢管混凝土拱桥吊杆钢丝的剩余疲劳寿命,以某服役满20年拱桥所更换下来的吊杆内部高强度钢丝为研究对象,进行不同时间的加速腐蚀,获得不同腐蚀程度的钢丝试件;对试件钢丝进行表观检测、称重、疲劳试验和断口形貌分析,得到了不同腐蚀程度下钢丝的表面粗糙度、质量损失率、断裂机理和疲劳寿命,通过Weibull模型对疲劳寿命数据进行分析,得到了不同失效概率下吊杆钢丝的剩余疲劳寿命公式。结果表明:随着腐蚀程度的增加,吊杆钢丝表面粗糙度和质量损失率的数值不断增加,疲劳寿命降低且疲劳断口均为脆性破坏,打磨后的钢丝疲劳寿命有所提升;相同失效概率下,吊杆钢丝剩余疲劳寿命将随着应力比的增加或腐蚀程度的增加而减少;研究结果可为吊杆钢丝的服役状态和疲劳寿命预测提供参考。

In order to assess the remaining fatigue life of the steel wire of in-service concrete-filled steel tubular arch bridge boom,the high-strength steel wire inside the replaced boom of an arch bridge that was in service for 20 years,was taken as the research object,and the steel wire was subjected to accelerated corrosion for different time to obtain steel wire specimens with different degrees of corrosion.The surface roughness,mass loss rate,fracture mechanism,and fatigue life of the steel wire under different degrees of corrosion were obtained through surface inspection,weighing,fatigue testing,and fracture morphology analysis.The fatigue life data were analyzed by using the Weibull model,and the remaining fatigue life formula of the boom steel wire under different failure probabilities was obtained.The results show that as the degree of corrosion increases,the surface roughness and quality loss rate of the boom steel wire continuously increase,the fatigue life decreases,and the fatigue fracture surface is brittle failure.The fatigue life of the polished steel wire is improved.Under the same failure probability,the remaining fatigue life of the boom steel wire will decrease with the increase of stress ratio or corrosion degree.The research results can provide reference for the service status and fatigue life prediction of boom steel wire.