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高强混凝土砌块砌体基本力学性能的试验研究及其动力分析
【作者】 祝英杰；
【导师】 刘之洋；
【作者基本信息】 东北大学 ， 结构工程， 2001， 博士
【摘要】 根据辽宁省科委项目“混凝土承重砌块节能住宅体系研究”的要求以及在八度抗震设防地区建高层砌块建筑的可行性,本文对高强混凝土小型砌块砌体的力学性能进行了试验研究:利用有限元法对长悬臂配筋砌块剪力墙的动力特性和弹塑性地震反应进行了分析。 本文对180个试件进行了轴压试验。试验结果表明,试件类型,砌块强度,填芯率和填芯混凝土强度对砌体的力学性能有较大影响,而砂浆强度对其影响较小;同时发现按《砌体结构设计规范》(讨论稿)中的公式计算,其抗压强度平均值明显高于试验值,偏于不安全,且弹性模量和泊松比都偏低。根据试验结果的统计分析,提出了计算砌块砌体抗压强度和弹性模量的建议公式,确定了泊松比的取值。经试验结果验证,计算值和试验值吻合较好,且偏于安全。 本文研究的是配筋砌块剪力墙的宏观地震反应,将配筋砌块剪力墙的组成材料简化成由两种材料构成:素混凝土砌体和钢筋。通过调整弹性矩阵来考虑钢筋对整体模型的贡献。从而在国内首次提出了配筋砌块剪力墙非线性有限元动力分析模型,包括本构关系、破坏准则和强化规律的确定。采用三维非协调实体元及改进子空间迭代方法计算剪力墙的特征对;采用平面应力单元并利用Newmark法与Newton—Raphson法相结合的方法计算剪力墙在地震荷载下的地震反应,并用FORTRAN77(F90)语言编制了相应的计算程序和前后处理程序,经计算验证程序是有效的。 利用编制的程序计算了剪力墙的自振周期和振型,并分析了填芯率、砌块强度等因素的影响,绘制了剪力墙三维振型图;计算了各结点的位移,加速度及各高斯点的应力反应;计算了顶层的最大结点位移,最大水平加速度和底层最大高斯应力点的时程反应,绘出了时程分析曲线;分析了填芯率、填芯混凝土强度、砌块强度和高宽比等因素的影响;分析了剪力墙在材料非线性及双重非线性下的地震反应;分析了剪力墙在水平方向、竖直方向及双向地震波作用下的地震反应;考虑了不同地震波对其地震反应的影响:分析了不同竖向分布荷载、不同地震设防水准和不同方向配筋情况下的剪力墙地震反应。 最后,提出了一些有意义的结论,指出了该结构在我国推广应用的前景。
【Abstract】 According to the need of the subject "Study on Saving Energy in House Buildings with Concrete Blocks" conveyed by Science and Technology Committee of Liaoning Province and the feasibility of constructing high-rise block buildings in the area of eight of earthquake intensity, an experimental study on the mechanical properties of the high-strength masonry panels with concrete small-size hollow blocks has been finished, and both the dynamic characteristics and the seismic behaviors of elastic and plastic state of long cantilever reinforced block shear walls have been analyzed by finite element method in this paper.180 specimens are tested in axial compression in the paper. The test results show that some significant factors affecting mechanical properties of masonry panels include specimen form, compressive strength of block, grouting ratio and strength of grouting concrete, but compressive strength of mortar has a little affection to it. Meanwhile, it is found that the calculation of compressive strength of panels using the formula in Code of Masonry Structure Design is much more that of test and not safety, modulus of elasticity of the masonry and Poisson’s ratio is lower than that of test. According to the statistics analysis of experiment results, the new formulas for calculating compressive strength and modulus of elasticity of masonry panels are presented, and the value of Poisson’s ratio is obtained . Reasonably good agreement has been found between the calculation using new formula and experimental results and calculation is suitable.This paper researches the seismic behaviors of reinforced block shear walls in macroscopic, so the material consisting of a shear wall is sampled with two kinds :pure concrete masonry wall and reinforced bars. A contribution of reinforced bars to the model is considered by modifying elastic matrix [D], A new model of finite element method for reinforced block shear wall is firstly proposed in this paper, including stress-strain relation, failure criterion and hard law are defined . Using three dimensional inharmonic element and the modified subspace iteration scheme for calculating dynamic characteristic of the shear wall, and using plane stress element and Newmark and Newton-Raphson method for calculation of seismic behaviors of shear wall under earthquake loads. Programs for calculation of dynamic characteristic and nonlinear analysis of response of the shear wall under earthquake loads has been made with