混凝土梁中钢筋内部应变差及其与荷载的关系  

Strain Variation Inside Steel Bars Embedded in Concrete Beams and Its Correlation With Loads

作　　者：刘思孟[1,2] 白煜 吴彩星 LIU Simeng;BAI Yu;WU Caixing(State Key Laboratory of Mountain Bridge and Tunnel Engineering(Chongqing Jiaotong University),Chongqing 400074,China;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]省部共建山区桥梁及隧道工程国家重点实验室(重庆交通大学),重庆400074 [2]重庆交通大学土木工程学院,重庆400074

出　　处：《北京工业大学学报》2020年第8期861-867,共7页Journal of Beijing University of Technology

基　　金：国家重点研发计划资助项目(2017YFC0806007);南京长江大桥公路桥维修改造关键技术研究资助项目(201727002)。

摘　　要：为了探究钢筋应变梯度大小随着荷载变化而产生的影响,采用理论分析方法研究钢筋混凝土梁截面的应变分布,导出钢筋应变差公式,开展钢筋混凝土梁的有限元分析.分析表明:钢筋上、下缘应变差与截面中性轴处曲率和钢筋直径有关,而曲率与荷载有关.在此基础上,开展了钢筋混凝土梁模型试验研究.分析试验数据发现:在加载过程中,钢筋上、下缘应变差随荷载增大而变大;受压钢筋应变差与荷载之间的关系更清晰;定量上,同一根受压钢筋的上、下缘应变差比率可高达50%.研究结果表明:在测量混凝土结构中钢筋的应变时,需充分考虑钢筋内部应变梯度的影响.In order to investigate the influence of the strain gradient of the reinforcement with the change of load,the theoretical analysis method was used to study the strain distribution on the reinforced concrete section,and the formula of the strain difference of the reinforcement was derived.For the reinforced concrete beam,a finite element analysis and model tests were carried out in this study.Theoretical analysis shows that the strain difference between the upper and lower edges of the reinforcement is related to the section curvature and the diameter of the reinforcement,and the section curvature is related to the load.The analysis of the test data demonstrates that during the loading process,the strain difference between the upper and lower edges of the steel bar increases with the increase of the load.The relationship between the strain difference of the compressed steel bar and the load is clearer.The strain difference ratio can be as high as 50%.The research results show that when measuring the strain of steel bars in concrete structures,the influence of the strain gradient inside the steel bars needs to be fully considered.

关 键 词：混凝土梁 钢筋应变 荷载 本构方程 平截面假定 截面曲率 

分 类 号：TU375.1[建筑科学—结构工程]