缅甸某悬索桥主缆开缆检测及承载力评估

为研究在役悬索桥主缆的腐蚀状况以及剩余承载力，对缅甸某服役25 a的悬索桥主缆进行开缆检测以及承载力评估. 首先，除去主缆外层防护，用楔子将主缆局部楔开，建立主缆开缆截面腐蚀分布图；其次，将实桥主缆钢丝分为4个腐蚀阶段，从缆内截取各阶段的样本钢丝进行实验分析；最后，采用简化模型对主缆剩余承载力进行评估. 研究结果表明:钢丝沿主缆径向由外向内腐蚀程度依次降低，最外层钢丝发生严重的基体腐蚀，样本钢丝腐蚀斑随腐蚀程度加深而尺寸逐渐扩大，钢丝强度和延展性随腐蚀程度加深而降低约3.50%和9.00%，上下游主缆强度降低约5.7%. 

Main Cable Opening Inspection and Bearing Capacity Evaluation of Suspension Bridge in Service in Myanmar

A cable opening inspection was made on a suspension bridge in service for 25 years in Myanmar to analyze the corrosion status and residual bearing capacity of the main cables. First, the outer protection layer of the main cable was removed; the main cable is partially split with wedge for detection, and the corrosion distribution diagram of the main cable cross-section was established. Then, the main cable steel wire of the bridge was divided into four corrosion stages, and samples of each stage were taken from the cable for laboratory analysis. Finally, a simplified model was used to evaluate the residual bearing capacity of the main cable. The results showed that the corrosion degree of the steel wires decreased from outside to inside along the radial direction of the main cable, and the outermost steel wire had serious matrix corrosion. As the corrosion level increased, the corrosion spot size of the sample steel wires expanded gradually, the strength and ductility of the steel wires decreased by about 3.50% and 9.00%, respectively, and the average tensile strength of the upstream and downstream main cables decreased by about 5.7%.