【作者】 臧登科；

【导师】 杨红；

【作者基本信息】 重庆大学 ， 结构工程， 2008， 硕士

【摘要】 作为用来模拟构件非线性反应的一种细化模型,纤维模型引起了各国研究者的普遍关注。已有研究成果表明,这种模型在较大的非线性变形状态下能较好与构件的实际变形相吻合,较之传统方法精度更高。然而,虽然纤维模型可以模拟构件的弯曲和轴向效应,并能很好地考虑弯曲和轴向效应的耦合,但它不能模拟构件的剪切效应。对于纤维模型中考虑剪切效应的模型化方法,国内外研究甚少。为了模拟构件的剪切变形,本文提出了考虑剪切效应的模型化方法。基于考虑剪切效应的模型化方法,以国外新近开发的结构非线性分析工具OpenSees为平台,重点研究了以下几个方面的内容:第一,在OpenSees中实现考虑剪切效应的模型化方法,从而形成对剪切效应的模拟;第二,基于试验结果的统计分析与回归对小跨高比连梁、短柱与剪力墙的剪切恢复力特征参数进行在中国实际情况下的校核与修正,并提出适应中国国情的定参公式。以几片典型剪力墙的抗震性能试验结果为标准点,对前面的模型化方法进行校准,得出:基于OpenSees平台纤维模型中考虑剪切效应的模型化方法能较好地模拟出剪力墙构件的实际抗剪承载力与最大位移,并且能够较好地模拟出试验中的刚度退化、强度退化和捏缩效应,具有一定的可靠性和稳定性。以此经过校准的模型化方法作为后续研究的理论依据;第三,以经过校准的考虑剪切效应模型化方法,对剪力墙的非线性变形能力进行系列分析。研究了剪跨比、轴压比、墙板配筋率、边框暗柱配筋率、混凝土强度、加载方式等主要因素对剪力墙非线性性能的影响规律;第四,基于本文提出的纤维模型中考虑剪切效应的模型化方法,借鉴已有研究结论,通过初步探讨研究得出,中性轴处最大的轴向变形可作为延性水平的标志,它与抗剪承载力有着一定的函数关系。本文通过引入一组与中性轴处最大轴向变形相关的剪力-剪应变骨架曲线,近似考虑了轴向、弯曲效应与剪切效应的耦合作用,并详细阐述了截面的剪切滞回模型,编制了程序流程图;第五,本文针对一严格按照我国规范设计的设防烈度为八度(剪力墙抗震等级为一级、框架抗震等级为二级)的高层民用建筑钢筋混凝土三维框架-剪力墙为例,以考察剪切效应对空间框架-剪力墙结构在罕遇地震作用下的非线性反应影响规律为重点,完成了以下研究内容,主要结论如下:①考虑剪切效应框架-剪力墙结构的整体反应明显大于不考虑剪切效应的整体反应。②考虑剪切效应的剪力墙模型可以更合理地反映剪力墙的实际抗剪承载力、剪切刚度、刚度退化、强度退化、捏缩效应及耗能情况,对比分析结果表明,不考虑剪切效应模型高估了剪力墙的抗剪承载力与剪切刚度及弯曲耗能能力,低估了剪力墙的剪切耗能能力。③在罕遇地震(a=0.46g)双向作用下,考虑剪切效应与不考虑剪切效应的空间框架-剪力墙的屈服机制、薄弱环节位置基本相同,考虑剪切效应模型的屈服杆件数量大于不考虑剪切效应模型的杆件数量。考虑剪切效应模型杆件损伤程度普遍大于不考虑剪切效应模型的杆件损伤程度,不考虑剪切效应的模型化方法低估了结构、构件的延性需求。这说明,不考虑剪切效应的模型化方法低估了整个空间结构的局部反应,对于整个空间结构的抗震性能评价是不利的。更多还原

【Abstract】 Many researchers pay more attention to fibre model which is a refining model for simulating nonlinear response of structural members. Research findings have proved, the model can anastomose well to actual deformation of members in biggish nonlinear deformation, and this methodological precision is higher than traditional method. However, fibre model can’t simulate shear effect of structural members, in despite of it can simulate bending and axial effect and it can consider well coupling action of bending and axial effect. The modelling method with shear effect in fibre model is researched at home and overseas rarely.The modelling method with shear effect in fibre model was put forward in the thesis for simulating shear deformation of structural members. Based on the modelling method with shear effect and OpenSees which was empoldered as a nonlinear analytical tool for structures overseas latterly, several aspects were researched as emphases.Firstly, the modelling method with shear effect in fibre model was carried out in OpenSees, consequently, shear effect was come true.Secondly, based on numerical statement and regression of experimental results, the shear resilience characteristic parameters of coupling beams with small aspect ratio, short columns and shear walls were checked and corrected in practical situation of China, and the formulas for confirming parameters which adapt for the situation of China were put forward. Using seismic experimental results of several piece typical shear walls as standard points, the modelling method foregoing was checked, several conclusions were drawn: the modelling method with shear effect in fibre model based on OpenSees can simulate well shear walls’ practical shear resistance and maximal displacement,and can simulate well stiffness degradation, strength degradation and rheostriction, the method has definite reliability and stability. The modelling method checked would be the theoretical foundation for latter research.Thirdly, by the modelling method with shear effect checked, nonlinear deformability of shear walls were analysed in series. Influence laws of aspect ratio, axial compression ratio, wall panel reinforcement ratio, embedded column reinforcement ratio, concrete strength and cyclic loading to nonlinear performance of shear walls were studied.Fourthly, based on the foregoing modelling method with shear effect and research conclusions reached, several conclusions can be obtained by preliminary study: the maximal centroidal axial deformation can be as a sign of ductile level, which is a function of shear resistance. Coupling action of bending and axial effect and shear effect was considered approximately by importing a set of skeleton curves of shear-shearing strain which correlates the maximal centroidal axial deformation, and sectional shear hysteretic model was expatiated, and the flow scheme of the analytical program was established.Fifthly, the analysis for a representative reinforced concrete public frame-wall in 8 region which was designed according to Chinese codes in this thesis, emphasize the nonlinear response influence law of shear effect to spatial frame-wall structures under rare earthquake action, some studies were carried out and the main conclusions can be obtained as followings:①The global responses of frame-wall structures with shear effect were bigger than the ones without shear effect clearly.②The model with shear effect can reflect the practical shear resistance, shear stiffness,stiffness degradation, strength degradation, rheostriction and energy consumed situation of shear walls in reason, and the model with shear effect overrates the shear resistance, shear stiffness and the capability of energy consumed by bending of shear walls, but underestimates the capability of energy consumed by shearing.③Under rare earthquake(a=0.46g) bidirectional action, the yielding mechanism, unsubstantial tache position of spatial frame-wall structures with shear effect were the same as the ones without shear effect basically, the number of yielding members of the model with shear effect was bigger than the one without shear effect. The damage extent of members was larger than the one without shear effect, and the modelling method without shear effect underestimates ductility demand of structures and members. It was indicated that the modelling method without shear effect underestimates local responses of the spatial structures, which was adverse to seismic performance evaluating of the whole spatial structures.更多还原