【作者】 鹿宁；

【导师】 张俊发；

【作者基本信息】 西安理工大学 ， 结构工程， 2008， 硕士

【摘要】 我国在建和拟建的大型水电站多数处于强地震活动区域,水电站厂房的抗震性能问题十分突出。长期以来,水电站厂房结构的抗震计算大多是基于线弹性材料未考虑水工钢筋混凝土在高荷载作用下所具有的明显的非线性特征。开展处在强烈地震作用下水电站厂房的弹塑性地震响应研究有重要的理论意义和实际应用价值。本文介绍了水电站厂房弹塑性地震分析的研究背景、分析方法、历史现状及问题的特殊性。以实际工程项目——某水电站厂房为研究背景,建立了有限元模型,并根据水电站厂房结构加速度的分布情况,推导建立了等效地震惯性力的方法。同时,基于ANSYS有限元程序对该水电站厂房进行了非线性地震分析。得到了地震情况下,结构不同方向上的结构延性、应力、塑性区域与裂缝的分布;探讨了考虑材料弹塑性后对结构抗震性能的影响,并得出了一些有意义的结论。本文的主要内容和结论如下:1、介绍了钢筋混凝土数值仿真中的各种混凝土本构模型、钢筋混凝土模型、裂缝模型,重点介绍了大型有限元通用程序ANSYS对于混凝土非线性本构模型及对混凝土开裂的处理方法。2、建立了某水电站厂房的有限元模型,通过模态计算分析,得到了结构的动力特性和加速度分布系数的分布情况,分析讨论了结构刚度、质量的分布,揭示了两种厂房结构动力性能的不同。3、本文采用了按以加速度分布情况作为水平惯性力的分布模式,并推导了相关的公式;同时,根据屈服对结构反应的减小作用,论证了静力弹塑性方法验算水电站厂房结构的抗震能力是有效的。4、用静力非线性方法对厂房结构进行计算,分析了在水平地震惯性力下的结构响应,建立了地震系数与顶点位移的关系曲线,计算了结构的延性系数,分析了结构随烈度加大,应力的发展规律、裂缝的出现顺序,讨论了结构的抗侧能力和容易产生裂缝的薄弱部位。5、本文提出的静力弹塑性方法能够在宏观上体现结构的抗震性能和在地震惯性荷载作用下的一些规律,并且得到了结构的薄弱部位,同时避免了采用动力时程方法计算时的困难。更多还原

【Abstract】 In China, many hydroelectric power stations in progress and planned are located in the region of strong earthquake activity. The problem of seismic performances in hydropower station powerhouse is quite distinct. For a long time, seismic calculation of hydropower station powerhouse structure has been based on the linear and elastic material, which does not consider the obvious nonlinear characteristics of hydraulic reinforced concrete under heavy load. The development of the elastoplasticity earthquake response of hydroelectric power station workshop under the strong earthquake function has the important theory significance and the practical application value.This paper has introduced the research background, the analysis method, the history present situation of the analysis on elastic-plastic earthquake response, and the peculiarity of this problem. Combined with one practical engineering project -a hydropower station powerhouse, a refined finite element model It has been established, and a method of equivalent seismic inertia force has been deduced according to the acceleration distribution of hydropower station powerhouse. Meanwhile, the nonlinear seismic response of powerhouse has been studied based on the finite element program (ANSYS). The structural ductility, stress, plastic zones and fracture distribution in different directions has been gotten, the effect of materials’ elasticity and plasticity to the aseismic performance has been studied, and a few useful conclusions were obtained. The main contents and conclusions are as follows:1、Concrete constitutive model, reinforced concrete model, and concrete crack model included inreinforced concrete numerical simulation has been introduced. Mainly the treatment of ANSYS to concrete nonlinear constitutive model and concrete crack has been introduced.2、In order to discover the differences of structural dynamic characteristics between two kinds ofpowerhouses, one hydropower house FEM model has been established, structure dynamic characteristic has been got, distribution coefficient of acceleration has been got, the distribution of structure rigidity and quality has been analyzed and discussed.3、The product of distributive acceleration as the horizontal inertia forces has been given, and correlated formula has been derived. Meanwhile, according to the reduced effect of yield to the structural response, the paper has demonstrated the effectiveness of checking the earthquake-resistant capacity for hydropower house using method of static elastic-plasticity.4、According the response of concrete workshop under horizontal earthquake effect with static nonlinear method, the curve between earthquake coefficient and top point displacement has been built, the structure ductile coefficient has been got, the law of stress’ development and the order of crack appearing with the intensity increasing has been analyzed, the lateral resistance capacity and the place apt to crack of concrete structure has been discussed.5、The method of static elastic-plasticity given in this paper, which can embodied structure earthquake-resistant capacity and a few law under effect of earthquake inertia forces, and found weak sections of the structure. Also the difficulty of calculate when using dynamic time history method has been avoided.更多还原