地震激励下在役RC框架结构力学行为研究

发布时间：2019-05-23 18:31

【摘要】：作为建筑结构中的一种基本结构体系，RC框架结构以其结构形式简单、平面布置灵活、传力路径明确等优点在我国乃至世界土木工程建设中扮演着重要角色。相对于其他新型结构体系而言，大量的RC框架建筑已步入中、老龄甚至超龄阶段，加之近年来我国及周边邻国的大区域地震活动预示中国大陆今后几年发生7级左右地震的可能性较大，，对地震激励下在役RC框架结构多尺度损伤行为进行研究并给出最优抗震设防建议迫在眉睫。论文以多龄期RC框架结构为研究对象，采用理论分析与数值模拟相结合的研究手段，探究了一般大气环境下主要建筑材料力学性能劣化机理与时变规律，揭示了多尺度地震损伤演化规律，定量评价了结构抗地震倒塌能力，最终获取了抗震投入和震害损失间的最佳平衡。主要研究工作和研究结论有：（1）对RC结构随内嵌钢筋锈蚀而出现性能劣化的4个重要阶段进行了界定，基于现场实测数据拟合得到了保护层混凝土碳化残量的建议计算模型，并运用弹性力学理论推导出保护层混凝土开裂时钢筋锈蚀率计算公式，揭示了混凝土抗拉强度、保护层厚度、纵筋直径、铁锈泊松比及锈胀率等主要因素的锈蚀敏感度，提出了内嵌钢筋未锈阶段服役时间和保护层混凝土锈胀开裂时结构服役时间的建议计算公式，最终给出了适用于多龄期RC框架结构的钢筋、混凝土及钢筋与混凝土间粘结滑移时变本构模型，为后续数值分析研究提供了基础理论支持。（2）基于ABAQUS软件平台，从单元选取与组合、混凝土破坏准则、材料时变本构关系及模型可靠性验证等方面探讨了适用于在役RC框架结构构件尺度的数值建模理论，并根据建议的RC框架结构诸类构件损伤表征量选取规则，给出了两类构件的损伤评价指标，通过在未锈RC梁构件抗弯刚度计算公式里引入粘结力修正函数以完成对受拉钢筋位置处混凝土平均拉应变的调整，进而提出了锈蚀RC梁抗弯刚度建议计算公式，计算分析了截面尺寸、混凝土强度等级、混凝土保护层厚度及配筋率等设计参数的损伤敏感度，揭示了主要设计参数对构件损伤演化的影响规律，为建立地震激励下在役RC框架结构损伤模型提供理论支撑。（3）基于OpenSees软件平台，重点探讨了RC构件力学性能在纤维层面上的描述方法，建立了适用于在役RC框架结构结构尺度的非线性有限元数值建模理论，并给出了RC框架结构宏观尺度损伤评价指标，揭示了构件类型和主要设计参数对楼层损伤的影响规律，提出了往复荷载作用下在役RC框架结构楼层损伤模型，进一步考察了损伤楼层位置、损伤楼层数量、楼层损伤程度及结构服役龄期对整体结构地震损伤的影响，最终建立了适用于在役RC框架结构的地震损伤模型。（4）通过对地震动记录和地震动强度指标选取准则的优劣性进行评价，给出了用于RC框架结构弹塑性地震响应数值分析的地震动记录和地震动强度控制指标，并就借助IDA方法实现对结构抗地震倒塌易损性分析所涉及的关键科学问题提供了解决方案，揭示了楼层高度、结构高宽比、框架柱轴压比及楼板约束强度等主要因素对典型锈蚀率下RC框架结构抗地震倒塌能力的影响规律，最终完成了在役RC框架结构抗地震倒塌能力的定量化评价。（5）采用分部优化法并借助复形法优化思想获取RC框架结构在弹性阶段的优化方案，通过控制优化结构的最大层间位移角以实现弹塑性阶段优化设计，从而得到了指定设防烈度下RC框架结构最小抗震投入的优化设计，并基于简化公式计算建筑结构遭受诸级破坏的失效概率，与单体建筑震害损失量化结果形成了共力，最终获得了指定设防烈度下框架结构的损失期望，随即将抗震投入最少和震害损失期望最小作为抗灾结构优化设计的两大优化目标，取目标函数值达到最小时的设防烈度作为结构最优设防烈度，进而搜索得到最优设防烈度下抗震投入与震害损失间的最佳平衡。
[Abstract]:As a basic structural system in the building structure, the RC frame structure plays an important role in the civil engineering construction of China and the world with the advantages of simple structure, flexible layout and clear force transmission path. With respect to other new structural systems, a large number of RC frame buildings have entered the middle, the aging and even the super-aging stage, and in recent years, the large-area seismic activity of our country and the surrounding neighboring countries indicates that the possibility of the earthquake in the Chinese mainland for the next few years is large, It is urgent to study the multi-scale damage behavior of the active RC frame structure under the earthquake excitation and give the optimal anti-seismic fortification. In this paper, a multi-age RC frame structure is used as the research object, and the research means of combining the theoretical analysis and the numerical simulation are adopted to explore the mechanism and time-varying law of the mechanical property degradation of the main building materials under the general atmospheric environment, and the evolution rules of the multi-scale earthquake damage are revealed. In this paper, the anti-seismic collapse capability of the structure is quantitatively evaluated, and the optimal level between the seismic input and the damage loss is finally obtained. Scale. Main research work and research conclusions The following results are as follows: (1)4 important stages of the performance degradation of RC structure with embedded steel bar corrosion are defined, and the suggestion of the residual amount of concrete carbonization of the protective layer is obtained based on the field-measured data fitting. The calculation formula of the corrosion rate of the steel bar in the crack of the protective layer concrete is derived by using the elastic mechanics theory, and the corrosion of the main factors such as the tensile strength of the concrete, the thickness of the protective layer, the diameter of the longitudinal bar, the Poisson's ratio of the rust and the scale of the rust and the like are revealed. In this paper, a formula for calculating the service time of the reinforced concrete and the structure service time of the concrete of the protective layer is proposed, and the time-varying time-varying between the reinforced concrete and the reinforced concrete and the concrete in the multi-age RC frame structure is finally given. The structure model provides the basis for the follow-up numerical analysis. On the basis of ABAQUS software platform, the number of component dimensions of RC frame structure is discussed from the aspects of unit selection and combination, concrete failure criterion, material time-varying constitutive relation and model reliability verification. The theory of value modeling is given, and according to the recommended RC frame structure, the damage evaluation index of the two types of components is given, and the cohesive force correction function is introduced in the calculation formula of the bending stiffness of the non-rust RC beam component to finish the average tensile force of the concrete at the position of the drawn steel bar. The calculation formula of the bending stiffness of the RC beam is proposed, and the damage sensitivity of the design parameters such as the cross-sectional dimension, the strength grade of the concrete, the thickness of the concrete protective layer and the reinforcement ratio is calculated and the damage evolution of the main design parameters to the component damage is revealed. The influence law of the structure of the RC frame structure in the service of the active RC frame under the earthquake excitation is proposed. For theoretical support, (3) Based on the OpenSees software platform, the paper mainly discusses the method of the description of the mechanical properties of the RC member on the fiber level, establishes the nonlinear finite element numerical modeling theory suitable for the structure scale of the in-service RC frame structure, and gives the macro scale of the RC frame structure. Based on the evaluation index of the degree of damage, the influence of the component type and the main design parameters on the floor damage is revealed, and the floor damage model of the active RC frame structure under the action of the reciprocating load is put forward, and the location of the damaged floor is further investigated. the effect of the number of the damaged floors, the degree of floor damage and the age of the structural service on the earthquake damage of the whole structure is finally established, The seismic damage model of RC frame structure is given in this paper. (4) The ground motion record of the elastic-plastic seismic response numerical analysis of RC frame structure is given by the evaluation of the good and bad of the ground motion record and the ground motion intensity index selection criterion. The ground motion intensity control index is used to provide a solution for the key scientific problems involved in the vulnerability analysis of the structural anti-seismic collapse by means of the IDA method, and the building is disclosed. The influence of the main factors, such as the height of the layer, the aspect ratio of the structure, the axial compression ratio of the frame column and the strength of the slab, on the anti-seismic collapse capability of the RC frame structure under the typical corrosion rate, and finally the anti-seismic inversion of the active RC frame structure (5) The optimization of the RC frame structure in the elastic phase is obtained by using the partial optimization method and the optimization of the structure of the RC frame structure by means of the complex method, and the maximum interlayer displacement angle of the RC frame structure is controlled by controlling the maximum interlayer displacement angle of the RC structure. The optimization design of the elastic-plastic phase is realized, and the optimal design of the minimum anti-seismic input of the RC frame structure with the specified fortification intensity is obtained, and the failure probability of the building structure subjected to the stage failure and the earthquake damage of the single building are calculated based on the simplified formula. The result of the loss quantification forms a common force, and finally obtains the loss expectation of the frame structure under the specified fortification intensity, and then the minimum of the seismic input and the expected minimum damage loss are the two optimization targets for the optimal design of the disaster-resistant structure, and the target function value is obtained for the most hour. As the optimal fortification intensity of the structure, the degree of seismic input of the optimal fortification intensity is further searched.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU375.4;TU311.3

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