TRC加固RC梁的弯曲疲劳破坏过程和应变发展的试验研究

发布时间：2018-06-03 19:48

本文选题：纤维编织网增强混凝土 + 受弯梁　；参考：《工程力学》2015年S1期

【摘要】：该文采用四点弯曲加载方式研究了加固方式、配网率、配筋率、损伤程度等对TRC加固RC梁疲劳寿命、破坏过程及应变发展的影响。试验结果发现:TRC加固梁在疲劳荷载作用下其破坏过程可以分为三个阶段。第一阶段:循环次数大约在4万次以内,新的裂缝会不断产生,此阶段末裂缝基本出齐,该阶段相对加固梁的整个寿命过程较短;第二阶段表现为加固梁的挠度几乎不变,该阶段末梁会产生新的裂缝,并形成主裂缝;第三阶段:加固梁的跨中挠度迅速增加,在时间很短的情况下梁发生疲劳破坏。加固梁的混凝土压应变与受拉钢筋应变随荷载循环次数的增加也呈三个阶段发展:初始发展、稳定发展和迅速发展。配网率和配筋率的增大都会减缓中和轴的上移速度,减小疲劳破坏时梁顶混凝土压应变,从而提高疲劳寿命。较大荷载作用下的静力损伤会使加固梁的钢筋应变提前进入第三阶段的发展,会减小RC梁的疲劳寿命。
[Abstract]:In this paper, the effects of strengthening mode, distribution ratio, reinforcement ratio and damage degree on fatigue life, failure process and strain development of RC beams strengthened with TRC are studied by using four-point bending loading method. The test results show that the failure process of the beam strengthened by TRC under fatigue load can be divided into three stages. The first stage: the number of cycles is about 40,000, the new cracks will continue to produce, at the end of this stage, the cracks are basically uniform, the whole life process of the strengthened beam is relatively short in this stage, and the second stage shows that the deflection of the strengthened beam is almost unchanged. At the end of this stage, new cracks will be produced and main cracks will be formed. In the third stage, the deflection in the middle span of strengthened beams increases rapidly, and fatigue failure occurs in the case of very short time. The compressive strain of concrete and the strain of tensile steel bar are also developed in three stages: initial development, steady development and rapid development. The increase of distribution ratio and reinforcement ratio will slow down the upward movement of the neutral axis and decrease the compressive strain of concrete at the top of the beam during fatigue failure, thus increasing the fatigue life. Static damage under large loads will advance the strain of reinforced beams into the third stage and reduce the fatigue life of RC beams.
【作者单位】：中国矿业大学深部岩土力学与地下工程国家重点实验室;中国矿业大学江苏省土木工程环境灾变与结构可靠性重点实验室力学与建筑工程学院;
【基金】：国家自然科学基金项目(51478458,51108451) 江苏省自然科学基金项目(BK2011220) 中央高校基本科研业务费专项资金项目(2014QNA79) 中国博士后和江苏省博士后基金项目(2014T70559,2012M511337,1102082C)
【分类号】：TU375.1

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