锈蚀钢筋混凝土梁疲劳性能试验研究  

Experimental investigation on the fatigue behavior of corroded RC beams

作　　者：易伟建[1] 孙晓东[1] 

机构地区：[1]湖南大学,湖南长沙410082

出　　处：《土木工程学报》2007年第3期6-10,共5页China Civil Engineering Journal

基　　金：国家自然科学基金(50378034);高校博士学科点专项基金(20030532020)

摘　　要：通过锈蚀钢筋混凝土梁的疲劳试验,分析了主筋锈蚀与混凝土梁疲劳性能的关系。疲劳试验包括1根钢筋未锈蚀的对比梁和8根钢筋锈蚀率介于4%～12%的试验梁。试验结果表明锈蚀钢筋混凝土梁的刚度在疲劳过程中表现出“下降—平稳—上升”三阶段特性。由于钢筋混凝土梁中钢筋的不均匀锈蚀,钢筋表面产生明显的坑蚀,锈蚀梁的疲劳破坏在应力幅最大且表面有坑蚀的钢筋截面发生。随着主筋锈蚀率的增加,梁的疲劳寿命急剧缩短,其破坏形式为受拉钢筋脆性断裂,破坏前没有预兆。振动测试表明,梁的基本频率并不是随疲劳损伤积累而单调下降,实测基本频率不能可靠地预报锈蚀钢筋的疲劳断裂破坏。同时,在相同疲劳循环次数下,随疲劳应力幅的增大,钢筋锈蚀的性能逐渐由软钢向硬钢转变。The fatigue property RC beams, including its relationship with the rusted main bars, was studied. A control RC beam without steel corrosion and eight RC beams with steel corrosion rates ranging between 4%-12% were tested under fatigue loading. The results of fatigue test showed that the stiffness of the beams performs with three distinctive stages under the fatigue cycle loads, i.e., decline-stabilize-rise stages. There were large amount of spot corrosions resulting from uneven corrosion of the main bars. Generally, the failure of the corroded RC beams occurred at locations with a high stress amplitude and with spot corrosions on the tensile steel bars. With the increase in the corrosion rate for the main bars, the fatigue lifespan of the corroded RC beams is shortened considerably. The fatigue failure of corroded RC beams occurred in the form of brittle fracture of tension steel bars without any precursors. The dynamic testing results showed that the fundamental frequency of corroded RC beams did not decrease monotonously with the cumulated fatigue damage. So the fundamental frequency obtained from the vibration test can not be used to predict the failure of the rusted main bar of the RC beams under fatigue loads. It was also shown that the rusted main bars were converted from the soft steel into hard steel with an increase in the fatigue stress amplitude under the same fatigue cycle loads.

关 键 词：钢筋腐蚀 锈蚀主筋 钢筋混凝土梁 疲劳试验 疲劳寿命 

分 类 号：TU375.1[建筑科学—结构工程] TG174.3[金属学及工艺—金属表面处理]