【作者】 万海涛；

【导师】 韩小雷；

【作者基本信息】 华南理工大学 ， 结构工程， 2010， 博士

【摘要】 钢筋混凝土梁、柱构件均为框架结构中特别重要的抗震构件,构件的变形是反映构件的抗震性能好坏的一种重要表征参数。本文在总结有关钢筋混凝土梁、柱构件和钢筋混凝土框架结构的大量文献资料的基础上,采用试验研究和非线性有限元分析相结合的方法对钢筋混凝土梁、柱构件的变形性能进行了研究和分析,得出梁、柱构件在不同地震水平下的变形限值,以期为今后既有的、新建的框架结构中的梁、柱构件性能评估提供定量参考指标。论文的主要工作和结论如下:1)本文设计了18根梁和32根柱进行低周反复加载试验,对50个梁、柱试件的试验过程、破坏形态、变形性能等进行了详尽的分析。通过试验得出梁和柱试件的荷载-位移滞回曲线、荷载-位移骨架曲线、开裂荷载、屈服荷载、峰值荷载、极限荷载,这为研究梁、柱构件的承载能力和变形限值提供了依据。本文还对比了配置小直径的CRB550级钢筋为箍筋的混凝土试件(梁和柱试件)与配置HPB235、HRB335级钢筋为箍筋的混凝土试件(梁和柱试件)在承载力和变形性能上的差异,分析对比后发现,它们的承载力和变形性能很接近,这表明在纵向配筋相同的情况下,完全可以采用比现今规范限值更小直径的CRB550级钢筋(如6.25mm、7.75mm、9.25mm)取代通常使用的直径为8mm、10mm、12mm的HPB235、HRB335级钢筋作为钢筋混凝土试件的箍筋。2)建立有限元分析模型对试验进行有限元仿真模拟,将试验和有限元模拟得到的梁、柱试件荷载-位移曲线、破坏形态及钢筋应变值进行对比分析,由对比分析可知,有限元模拟结果与试验结果吻合较好,这表明有限元分析模型可以较为准确地模拟梁和柱试件的试验情况。3)根据钢筋混凝土梁试件的破坏类型,设计了240根钢筋混凝土梁试件来进行变形性能计算,由有限元分析模型计算得出钢筋混凝土梁试件在小震、中震、大震时的变形限值,并进一步分析了影响梁试件变形限值的主要因素,结果表明:随着主要因素K值增大,试件的荷载-变形骨架曲线走势由平缓慢慢变陡,即随着K值增大试件的延性变差;随着主要因素λ值增大,试件的荷载-变形骨架曲线走势由陡慢慢变平缓,即λ值越大试件的延性越好。4)根据钢筋混凝土柱试件的破坏类型,设计了324根钢筋混凝土柱试件来进行变形性能计算,由有限元分析模型计算得出钢筋混凝土柱试件在小震、中震、大震时的变形限值,并进一步分析了影响柱试件变形限值的主要因素,结果表明:随着主要因素n值增大,试件的荷载-变形骨架曲线走势由平缓慢慢变陡,即随着n值增大试件的延性变差;随着主要因素λ值增大,试件的荷载-变形骨架曲线走势由陡慢慢变平缓,即λ值越大试件的延性越好。5)将梁和柱试件在弯曲破坏、弯剪破坏、剪切破坏时的最大变形限值与美国规范ASCE41中的相应变形限值进行对照比较,比较后发现美国的变形限值比本文计算的变形限值要宽松,这主要是因为美国规范中所用的建筑材料延性比我国的建筑材料延性要好。6)在综合考虑钢筋混凝土梁和柱试件塑性铰长度影响因素的基础上,对钢筋混凝土梁和柱试件的塑性铰长度lp进行回归分析,得出钢筋混凝土梁和柱试件的塑性铰长度估算公式,然后用相关性系数(R-square)来评价公式拟合的好坏,计算得到梁和柱试件的相关性系数(R-square)分别为90.12%、96.36%,这表明梁和柱试件的塑性铰长度估算公式对数据拟合的较好。更多还原

【Abstract】 Reinforced concrete beams and columns are particularly important anti-seismic component in the frame, the deformation of the component is an important characterization parameter for reflecting the performance of components good or not. Based on the conclusion of an amount of references about reinforced concrete beams ,columns and frames, the paper studies the deformation performance of reinforced concrete beams and columns under small earthquake, moderate earthquake and severe earthquake to get the deformation limit of the beams and columns by test and nonlinear finite element analysis method, which would be used in the beams and columns of existing and future frames as a indicator for the performance evaluation. The main work and conclusions are as follows:1) In the paper, 18 beams and 32 columns are designed for low cyclic loading tests, and testing process, failure mode, deformation performance of 50 specimens are carried out a detailed analysis. Force-displacement hysteresis curves, force-displacement skeleton curves , cracking load, yield load, peak load, ultimate load of beam and column specimens are obtained from the test, which provides a basis for studying the bearing capacity and deformation limits of specimens. The paper also compares the differences of concrete specimens (beam and column specimens) using small diameter CRB550 stirrups and those using HPB235, HRB335 stirrup in the bearing capacity and deformation performance. Analysis and comparison reveals that the bearing capacity and deformation performance of them are very close, which indicates that in the same longitudinal reinforcement, the CRB550 small diameter steel bar (such as 6.25mm, 7.75mm, 9.25mm) can be used to replace HPB235, HRB335 steel bar of diameter 8mm, 10mm, 12mm as the stirrups of the reinforced concrete specimens (beam specimens and column specimens).2) The test is simulated by the finite element analysis method, and the finite element simulation results are compared with the test results for load-displacement curves, failure modes and reinforcement strain. By the comparative analysis, the finite element simulation results agree well with test results, indicating that the finite element analysis method can be accurately simulate the beam and column specimens test situation.3) According to the failure types of the reinforced concrete beam specimens, 240 reinforced concrete beam specimens are designed to calculate deformation performance, and to get the deformation limit of the reinforced concrete specimen through the finite element analysis model under small earthquake, moderate earthquake and severe earthquake, and further to analyze the factors influencing the deformation limits of beam specimens. The results show that: with the increases of the main factor K value , the load-deformation skeleton curve of the specimen become cliffy from gentle, so the ductility get worse with the K value increases. As the main factorλvalue increases, the load-deformation skeleton curve of the specimen become gentle from cliffy, so the ductility get better with theλvalue increases.4) According to the failure types of the reinforced concrete column specimens, 324 reinforced concrete column specimens are designed to calculate deformation performance, and to get the deformation limit of the reinforced concrete specimen through the finite element analysis model under small earthquake, moderate earthquake and severe earthquake, and further to analyze the factors influencing the deformation limits of column specimens. The results show that: with the increases of the main factor n value, the load-deformation skeleton curve of the specimen become cliffy from gentle, so the ductility get worse with the n value increases. As the main factorλvalue increases, the load-deformation skeleton curve of the specimen become gentle from cliffy, so the ductility get better with theλvalue increases.5) Comparing the maximum deformation limits of the beam and column specimens for bending failure, bending-shear failure, shear failure with U.S. code ASCE41, the deformation limits of the United States should be relaxed than the paper. It is mainly because building materials used in the United States is better ductility than ours.6) Considering the factors influencing plastic hinge lengths of reinforced concrete beam and column specimens, statistical regression of the plastic hinge length of the reinforced concrete beam and column specimens are obtained, as well as the estimation formula of plastic hinge length of reinforced concrete beam and column specimens. Then the correlation coefficient (R-square) is used to evaluate the fit of this formula, the calculated correlation coefficient of beam and column specimens (R-square) are 90.12%, 96.36%, indicating that the estimation formula of the plastic hinge length of the beam and column specimens is suitable.更多还原