【作者】 李鹏；

【导师】 易伟建；

【作者基本信息】 湖南大学 ， 结构工程， 2013， 博士

【摘要】 基于性能的抗震设计对于结构构件的能力需求不仅仅局限在极限承载力和弹性变形能力上，同时对结构构件延性变形、滞回耗能等抗震性能也有了明确的需求。根据性能设计要求进行结构构件设计，需要建立构件基本参数与抗震性能之间的数值关系。本文从国内外规范、试验研究、数值分析多个方面对钢筋混凝土柱截面延性、位移延性和塑性铰长度等抗震性能参数的影响因素、计算方法和统计概率分布等进行了分析与研究，其主要内容如下：1.配箍率作为影响钢筋混凝土柱延性的一个主要参数，已经受到国内外学者和结构设计规范的关注。本文介绍了国内外主要规范对于钢筋混凝土柱最小配箍率的相关规定。计算对比了各国规范中最小配箍率对截面延性的影响。讨论了我国规范按照最小配箍率所能获得的柱截面延性，并对最小配箍率的设置提出了建议。2.本文设计了4根钢筋混凝土悬臂柱，并对其进行了低周反复荷载试验。试验中主要测试内容是柱顶位移、箍筋应变。试验获得了在压弯作用下箍筋应变分布和变化情况，为柱截面混凝土所承受的约束应力计算提供了试验数据支持。同时通过变化轴压比、加载方式，讨论了这两个因素对柱抗震性能的影响。试验结果表明轴压比和加载方式对于柱破坏形态、箍筋应变分布影响显著。总结了箍筋应变在柱截面内沿环向分布规律和沿柱高度方向的变化规律。3.对试验获得的箍筋应变数据进行整理分析，导入钢筋应力-应变全曲线，通过分析得到了柱试验过程箍筋应力分布和变化数据。从而得到箍筋约束的柱截面混凝土受到的约束力分布情况。根据Mander的约束理论，计算出有效约束系数，可以得到箍筋间弱约束截面的约束应力分布情况。通过引入混凝土膨胀参数，对约束应力进行计算，从而改进计算柱截面延性的纤维模型。利用改进的纤维模型，对影响截面曲率延性的各个参数进行了分析，并通过回归分析建立了截面曲率延性与配箍特征值、轴压比、纵向配筋率和核心混凝土面积比之间的关系。与其他基于性能的截面延性设计方法计算结果相比，本文建议的方法准确度相对较高，能较好反映曲率延性系数的变化规律。4.位移延性作为最基本的构件抗震性能指标，有众多的影响参数。按照Priestly的计算方法，可以采用两个主要参数来计算柱位移延性，分别是截面延性和塑性铰长度。本文从美国太平洋地震研究中心提供的柱试验数据中选取了143个滞回曲线完整且破坏形态为弯曲破坏的柱试验数据，通过计算分析得到柱等效塑性铰长度。再通过回归分析，获得了等效塑性铰长度的计算公式。经试验结果的验证，本文建议的公式具有较高的计算精度。本文收集了国内45个混凝土柱的抗震试验结果对本文建议的方法进行检验，结果表明采用本文建议的方法计算得到的位移延性均值与试验结果的均值基本一致，其误差基本能保证在20％以内，相对误差呈正态分布。5.基于性能的抗震设防理念必然和不同地震作用下结构抗震性能指标相联系。而位移是最为直观的指标之一。通过对直接基于位移的抗震设计方法和基于性能的多目标抗震思想的研究，本文提出了基于位移的多水准抗震设计方法。这一设计方法首先根据业主的要求确定不同烈度地震作用下对结构位移性能的预期与需求。通过位移需求构造需求曲线，而结构的抗震性能将按照这一曲线，采用改进的直接基于位移的能力谱方法进行设计。采用一个单自由度桥墩的设计过程介绍了基于位移的多水准设计方法的设计流程。更多还原

【Abstract】 Performance-based seismic design is demanded in ultimate bearing capacity and elasticdeformation capacity of structural components, as well as other seismic performances, such asductility deformation and hysteretic energy dissipation. The design of structural componentbased on performance requirements require to establish value relations between the basicparameters of components and seismic performance.In this dissertation, the seismic performance parameters, including the ductility ofreinforced concrete columns section, displacement ductility and length of plastic hinge,calculation method and statistical probability distribution are researched from the domesticand international norms, experimental study, numerical analysis and other related perspectives,and the main contents are as follows:1. Stirrup ratio, as a main parameter affecting the ductility of reinforced concrete column,is focused on by scholars at home and abroad and the structure design code. This paperintroduces relevant provisions of minimum stirrup ratio of specification for reinforcedconcrete column defined in main domestic and foreign regulations. The influence of minimumstirrup ratio defined in many countries’ regulations on the ductility of sections is comparedand calculated. The ductility of the column section obtained from the minimum stirrup ratioaccording to China’s norms is discussed, and the recommendations are put forward for settingof minimum stirrup ratio.2. This paper designs4reinforced concrete cantilever columns which experience the lowcyclic loading test. The main test contents are top displacement and stirrup strain. The testobtains stirrup strain distribution and variation under the action of bending, providing datasupport for computational constraints under column section stress of concrete. Throughchanging the axial compression ratio and loading mode, the influence of the two factors onthe seismic behavior of columns is discussed. The test results show that the axial compressionratio and the loading pattern have significant effect on column failure mode and stirrup straindistribution. The distribution of stirrup strains along circumferential direction in columnsection and its change along the column height are summarized.3. Data of stirrup strain obtained in tests are analyzed, steel stress-strain curve isintroduced, and the analysis leads to data about stirrup stress distribution and variation incolumn test process; followed by binding distribution results of concrete on column sectionconfined by the stirrup. According to Mander’s theory of constraints, the effective restriction factors are calculated, and the stress distribution between weak constraint sections confinedby stirrups can be obtained. The introduced concrete expansion parameters can help tocalculate the constraint stress, thus improving fiber model to calculate the column sectionductility. The improved fiber model facilitates analysis of various parameters affecting thesection curvature ductility whose relations with vegin value, axial compression ratio,longitudinal reinforcement ratio and core concrete area ratio are worked out. Compared withother performance-based section ductility design method and calculation results, the methodproposed in this study, with its high accuracy, can better reflect the change of the curvatureductility coefficient.4. Many parameters can affect displacement ductility which is the most basic seismicperformance index. According to the calculation method of Priestly, two main parameters, thesection ductility and plastic hinge length, can be adopted to calculate the column ductility. Inthis study,143column test data with complete hysteretic curve and flexural failure from theUnited States Pacific Earthquake Engineering Research Center are selected, and accordingly,the equivalent plastic hinge length of column is calculated. Through regression analysis,formula for calculating the equivalent length of plastic hinge is obtained. It has been verifiedby the test results, the calculation accuracy of the proposed formula is higher. Then45seismicexperiment results of concrete columns are adopted to test the proposed method, the resultsshow that displacement ductility mean calculated by the proposed method are basically thesame as mean experiment results, the error can be controlled within20%and the relative errordisplays normal distribution.5. Performance-based seismic fortification concept must be associated with indexes ofstructural seismic resistance for different earthquakes, while displacement is one of the mostintuitionistic indexes. Based on research of direct displacement-based seismic design andperformance-based multi-objective anti-seismic thought, this paper puts forward themult-standard displacement-based seismic design method which firstly determines theexpectations and demands on the performance of structure displacement under differentearthquake intensities according to the requirements of owners. The displacement demand ishelpful for establishment of demand curve according to which the seismic performance of thestructure is designed with the method of improved displacement-based capacity spectral.Finally the design process of a bridge pier with single degree of freedom is introduced toexplain displacement-based multi-level design method.更多还原