【作者】 张皓；

【导师】 李宏男；

【作者基本信息】 大连理工大学 ， 结构工程， 2012， 博士

【摘要】 钢筋混凝土结构是应用最为广泛的一种结构形式,在役期间,不可避免的要遭受到地震等动力荷载的作用。近年来,强烈地震时有发生,地震力作用导致钢筋混凝土结构破坏的现象经常出现。由于钢筋和混凝土均为应变率敏感性材料,在地震等动力荷载作用下材料的力学性能将会发生改变,地震力作用下的钢筋混凝土构件及结构的力学性能、变形性能和破坏模式都会受到材料应变率效应的影响。目前,关于地震力作用下应变率效应对结构材料以及材料应变率效应对钢筋混凝土结构及构件影响的研究相对较少。本文采用试验研究、数值模拟及理论分析的方法对动力模型试验用微粒混凝土和镀锌铁丝在地震作用应变率范围内的动态抗压性能和动态拉伸性能,钢筋混凝土框架-剪力墙结构动力模型试验,材料应变率效应对钢筋混凝土剪力墙动态性能的影响,材料应变率效应对钢筋混凝土结构地震反应的影响几方面进行了研究,完成了以下主要研究内容：(1)对钢筋混凝土结构动力模型试验中经常用来代替混凝土的微粒混凝土进行了地震作用应变率下的动态抗压性能试验。根据试验结果,回归分析得到了微粒混凝土抗压强度和弹性模量动力提高系数(DIF)与应变率之间的关系。基于混凝土结构设计规范(GB50010-2010)给出了微粒混凝土单轴受压率相关本构模型。采用ABAQUS软件中的混凝土损伤塑性模型结合所提出的微粒混凝土单轴受压率相关本构模型对微粒混凝土的动态抗压性能进行了数值模拟,与试验结果的对比分析表明微粒混凝土单轴受压率相关本构模型能够很好的描述微粒混凝土的动态抗压性能。(2)钢筋混凝土结构动力模型试验中的钢筋通常使用镀锌铁丝来模拟,对三种不同型号的镀锌铁丝进行了动态拉伸试验研究,对比分析了地震作用应变率下三种不同型号镀锌铁丝的力学和变形特性。根据试验结果,通过回归分析的方法给出了镀锌铁丝动、静拉伸强度与应变率之间的关系方程。通过与钢筋模型的对比分析表明,两者的动态拉伸性能较为相似,在振动台试验中用镀锌铁丝来模拟钢筋的动态力学性能是可行的。(3)根据相似理论设计并制作了一个三层偏心钢筋混凝土框架-剪力墙结构振动台试验模型。利用地震模拟振动台对钢筋混凝土框架-剪力墙模型进行了水平和竖向地震波同时输入下的双向加载振动台试验。通过试验了解了偏心钢筋混凝土框架-剪力墙结构在地震作用下的反应特性与破坏形态。同时,试验结果也为验证后续章节中考虑材料应变率效应的钢筋混凝土结构弹塑性地震反应分析的准确性提供了依据。(4)钢筋混凝土剪力墙是混凝土结构中的重要构件,关于钢筋混凝土剪力墙动态性能方面的研究工作相对较少。为了解材料应变率效应对钢筋混凝土剪力墙动态性能的影响,作者基于ABAQUS软件建立了钢筋混凝土剪力墙的有限元模型,分别对不同剪跨比和轴压比的钢筋混凝土剪力墙在不同应变率的动力荷载作用下的动态性能进行了数值模拟,数值模拟结果可以为钢筋混凝土剪力墙动态性能的试验研究提供一些可供参考的理论依据。(5)针对钢筋混凝土结构弹塑性地震反应分析的研究中很少考虑材料应变率效应,本章进行了考虑材料应变率效应的钢筋混凝土结构弹塑性地震反应分析。开发了基于ABAQUS软件可以考虑材料应变率效应的微粒混凝土动态纤维梁单元子程序,建立了振动台试验中偏心钢筋混凝土框架-剪力墙结构的有限元模型,在通用有限元软件ABAQUS中调用子程序对试验模型进行了弹塑性地震反应分析,分析中考虑了材料应变率效应的影响,研究结果表明：数值模拟结果与试验结果吻合较好,验证了微粒混凝土动态纤维梁单元子程序对模型进行考虑材料应变率效应弹塑性地震反应分析的准确性；并对考虑材料应变率效应与未考虑材料应变率效应的计算结果进行对比分析,分析结果显示,考虑材料应变率效应时的计算结果较为准确。同时,建立了一个高层剪力墙结构的有限元模型,分别进行了考虑材料应变率效应和未考虑材料应变率效应的弹塑性地震反应分析,研究结果表明：考虑材料应变率效应下的分析结果与未考虑材料应变率效应时存在一定的差别,随着地震输入加速度峰值的增大,应变率效应对结构地震反应的影响越发明显,因此应该在抗震设计与分析中适当考虑材料应变率效应。更多还原

【Abstract】 The reinforced concrete structures are widely used and required to resist dynamic loads when subjected to seismic loading during the period of its active service. In recent years, the reinforced concrete structure may suffer distress under the action of unforeseen strong earthquake which is often occurs. Reinforcing steel and concrete are both sensitive to strain rate, hence, the mechanical properties of them will be changed by the strain rate effect. The mechanical properties, deformational properties and failure mode of reinforced concrete structures and members will be changed, too. There is very little research about the effects of strain rate on reinforced concrete materials, members and structures subjected to seismic loading. In this paper, the strain rate sensitivities of microconcrete and galvanized wire, the effects of strain rate on reinforced concrete shear walls and structures under seismic loading were investigated. A shaking table test of reinforced concrete shear wall structure was also carried out. The main aspects of research work in this thesis are listed as follows:(1) The dynamic compressive properties of miroconcrete which is most popular used in dynamic model test for replacing concrete are experimentally investigated under the strain rate of earthquakes. Based on the tested results, the dynamic increasing factor (DIF) of compressive strength and elastic modulus which are function of strain rate are obtained by regression analysis. The uniaxial compressive constitutive model of the microconcrete with strain rate effect is fitted by using the compressive stress-strain relationship of concrete in the China code for design of concrete structures (GB50010-2010). The dynamic compressive properties of microconcrete are analyzed in finite software ABAQUS by using the damaged plasticity model and the presented uniaxial compressive constitutive model of the microconcrete. The comparison between the numerical results and tested results show that the presented model can describe the dynamic properties of microconcrete very well.(2) The galvanized wires are often used to simulate the reinforcing steel in the dynamic model test. The dynamic tensile test on galvanized wires are carried out, and the mechanical and deformation properties of galvanized wire under the seismic strain rate are investigated. Based on tested data, the relationship of dynamic increasing factor of yield strength and tensile strength which are function of strain rate-are gotten. According to the comparison with the reinforcing steel models, the dynamic tensile properties of galvanized wire and reinforcing steel are very similar. In the dynamic model tests, it is feasible for using the galvanized wires to simulate the reinforcing steels.(3) A three-story reinforced concrete frame-wall shaking table test model is designed and made on the basis of the similarity theory, and bi-directional shaking table experiment was carried out. The seismic response and failure mode of reinforced concrete frame-wall structure are investigated by the shaking table test. Meanwhile, the tested results which are obtained from the shaking table test provide evidence for the nonlinear seismic response analysis of the reinforced concrete structure.(4) Reinforced concrete shear wall is the typical member in reinforced concrete structure. The research about the dynamic properties of shear wall is relatively scarce. In order to understand the effects of strain rate on the dynamic properties of reinforced concrete shear wall, the finite element model of reinforced concrete shear walls are established in the software ABAQUS. The numerical simulation of the dynamic properties of reinforced concrete shear walls under different strain rates are carried out, which consist of different height-to-width ratio and axial compressive ratio. The numerical results provide theoretical basis for the dynamic experiments of the reinforced concrete shear wall.(5) The research about strain rate effect of materials affected on the response of reinforced concrete structure under seismic loading is limited, hence, the elastoplastic seismic response analysis with strain rate effect of reinforced concrete structure are studied. Based on the uniaxial compressive constitutive model of microconcrete with strain rate effect, the dynamic fiber beam element subroutine of microconcrete in software ABAQUS is given. The finite element model of reinforced concrete frame-wall structure in the shaking table test in this paper is established, and the elastoplastic seismic response analysis with strain rate effect is carried out by using the dynamic fiber beam element subroutine of microconcrete. The numerical results are consistent with the tested results, and the comparison between the numerical results and tested results show that the dynamic response of reinforced concrete shaking table model can simulate by the dynamic fiber beam element subroutine of microconcrete in software ABAQUS accurately. The calculated results with strain rate effect and without strain rate effect are compared with eachother, and results show that the case with strain rate effect is more accurate. Meanwhile, a finite element model of high-rise shear wall structure is established and the effects of strain rate on the dynamic response of the model under seismic loading are investigated. The results show that the effects of strain rate are more obvious with the increasing peak value acceleration of input motion. Hence, the strain rate effect should be considered properly in the seismic design and analysis.更多还原