碳化-冻融作用下钢筋混凝土梁承载力衰减分析  

Analysis on Load Capacity Attenuation of Reinforced Concrete Beam after Carbonization and Freeze-Thaw Action

作　　者：苏有彪 胡大琳[1] 张航 陈峰[1] 徐怀存 SU You-biao;HU Da-lin;ZHANG Hang;CHEN Feng;XU Huai-cun(School of Highway,Chang'an University,Xi'an 710064,China;CCCC First Highway Consultants Company Limited,Xi'an 710075,China)

机构地区：[1]长安大学公路学院,西安710064 [2]中交第一公路勘察设计研究院有限公司,西安710075

出　　处：《硅酸盐通报》2019年第4期948-956,共9页Bulletin of the Chinese Ceramic Society

基　　金：交通运输部应用基础研究项目(2013319812100);国家自然科学基金(51808048)

摘　　要：为了研究碳化-冻融环境对钢筋混凝土梁承载力的影响,对钢筋混凝土试验梁进行了多重循环碳化-冻融交替作用下的加速腐蚀试验,然后对完成腐蚀试验的钢筋混凝土梁进行抗弯荷载试验。通过荷载试验获得腐蚀梁的应变变化、裂缝发展及荷载位移曲线,分析碳化-冻融耦合作用对试验梁承载力衰减的影响。结果表明:荷载试验过程中腐蚀钢筋混凝土梁的跨中截面应变基本满足平截面假定,相同荷载下受腐蚀梁的跨中应变大于未腐蚀梁的应变值;与未腐蚀钢筋混凝土梁相比受腐蚀梁的裂缝出现的较早,裂缝较宽、数量较少;从试验梁的荷载-位移曲线可知同一级别荷载作用后梁体跨中位移值随碳化-冻融腐蚀周期的增加而增大,极限荷载随腐蚀周期的增加而降低。根据试验梁荷载试验的实测数据提出了钢筋混凝土梁在全寿命周期内承载力时变衰减系数的计算公式,并通过有限元模拟分析验证了其正确性,该系数可用于我国严寒区钢筋混凝土结构的承载力衰减模拟分析和评估,成果可为实际工程参考。In order to study the influence of load capacity of RC beam due to carbonization and freeze-thaw action, accelerated corrosion test of RC beam under multi-cycle of carbonization and freeze-thaw alternating action was carried out, then the bending load test of the beam was also carried out. The strain change, crack development and load-displacement curves of corroded beams were obtained during load test, the influence of carbonization and freeze-thaw coupling on the load capacity attenuation of the beam was analyzed. The results show that the strain of the mid-span section of corroded RC beam is mainly satisfied the plane-section assumption in the course of the load test, strain of the mid-span of the corroded beam is larger than that of the uncorroded beam under the same load level. The cracks of corroded RC beam appeares earlier than those of uncorroded beam, cracks are wider and less in number. According to the load-displacement curve of the beam, it can be known that mid-span displacement of the beam increases after the same load level action and the ultimate load decreases with the increase of carbonization and freeze-thaw corrosion cycle. Based on the test data of the beam, a formula for calculating time-varying attenuation coefficient of RC beam in the whole life cycle is presented, and the consistency of the coefficient is verified by finite element simulation, this coefficient can be used to simulate and evaluate the load capacity attenuation of reinforced concrete structures in cold regions of China, the results can be referred for practical engineering.

关 键 词：钢筋混凝土梁 碳化 冻融 衰减 承载力 

分 类 号：TU375.1[建筑科学—结构工程] U444[建筑科学—桥梁与隧道工程]