侵蚀性环境下桥梁CFRP/BFRP加固后的长期性能试验

Experiment for Long-term Performance of Bridge Girders Strengthened with CFRP/BFRP Sheets and Subjected to Erosion Environment

为了研究侵蚀性环境下服役桥梁构件采用纤维材料加固后的长期性能,对11根具有初始锈蚀损伤的钢筋混凝土梁式构件采用碳纤维布(CFRP)和玄武岩纤维布(BFRP)加固后继续退化的承载力及服役性能进行试验。通过对加固后构件进行电化学加速锈蚀和盐液浸润干湿循环模拟不同程度的后续服役性能退化,研究侵蚀性环境对CFRP和BFRP加固构件在不同后续服役期的承载力、刚度等性能影响规律,同时对比了2种加固材料的耐久性能和成本效益。结果表明:侵蚀性环境下加固后的桥梁构件承载能力评估需综合考虑钢筋锈蚀引起的承载力降低和侵蚀性环境对纤维利用效率的降低;CFRP对刚度提高显著,而BFRP加固具有更好的延性;考虑加固后长期服役性能,CFRP加固后具有较好的耐久性,而BFRP具有较高的成本效益。

Abstract. To investigate the long-term performance of existing bridge girders strengthened with fiber reinforced plastics （FRP） sheets and subjected to erosion environment, the bearing capacity and service performance experiments of＂ 11 reinforced concrete （RC） girders, which were strengthened with carbon fiber reinforced plastics （CFRP） and basalt fiber reinforced polymer （BFRP） sheets after initial corrosion damage, were conducted. Different subsequent performance degradations for strengthened girders were simulated through electrochemical accelerated corrosion together with wet/dry cycles of salt solution. The effect of environmental erosion on capacity, stiffness and other parameters of CFRP/BFRP strengthened girders in different follow- up service time was tested. The durabilities and costs of the two strengthening materials werealso investigated. The results show that the capacity evaluation of bridge girders strengthened with FRP sheets should consider the effect of rebar corrosion together with the environmental reduction of FRP strengthening; the CFRP strengthening improves the stiffness obviously but BFRP strengthening shows better ductility; when considering long-term performance, CFRP sheets strengthening provides better durability while BFRP strengthening displays better cost ef- fectiveness.