CFRP加固初始损伤桥梁构件性能监测试验研究

Performance Monitoring of Damaged Bridge Members Strengthened with Carbon Fiber Reinforced Polymer

由于使用过程中的汽车超载作用和环境侵蚀作用导致既有钢筋混凝土桥梁不可避免地发生损伤,引起变形过大和承载力下降从而影响其使用性能,必须采取维修加固措施方可继续服役.本文通过静载试验模拟汽车超载作用,通过恒电流加速锈蚀试验模拟氯盐侵蚀环境下混凝土构件承载力退化,采用CFRP对存在初始损伤的桥梁构件进行了加固,并采用分布式光纤传感技术(BOTDA)监测了构件内部应变,对比分析了加固前后的挠度、裂缝及应变变化情况.试验结果表明,不同的初始损伤对碳纤维加固效果影响不同,引起较大残余变形的超载损伤对加固后桥梁构件的协同工作能力有明显的降低影响.构件内布设传感光纤在超载状况和钢筋锈蚀情况下均可保证稳定、可靠的性能监测,可用于智能桥梁的设计实施和既有桥梁的实时监测.

Aggressive environmental conditions and ever-increasing traffic loading contribute to the progressive deterioration, increase the deflection and decrease the capacity of bridge structures over their lifetime. Therefore, maintenance and repair methods should be implied for the requirement of serviee security. The traffic overload was simulated by static load test, the rebar corrosion was generated by Galvan static method, and the carbon fiber reinforced polymer was used to strengthen these damaged bridge members. Then the BOTDA was adopted to monitor the strain changes in the experiment. The reinforcement effect of CFRP was evaluated by comparing the deflection, crack pattern and strain under various stages. The experimental investigation indicates that damages caused by different factors affect the reinforcement efficiency in different ways. Traffic overload, which causes a comparable large deflection, leads to self-evident interoperability reduction of the strengthened bridge member. The fiber optical sensors embedded in bridge members can monitor the structure performance reliably and stably under traffic overload and erosion environment condition, and it is proved that BOTDA has extensive prospect for monitoring the smart bridge and structures.