【作者】 茹文恺；

【导师】 易伟建；

【作者基本信息】 湖南大学 ， 结构工程， 2010， 硕士

【摘要】 近年来国内外学者对二阶效应与近场地震进行了很多研究,也得到了一些有用的结论。但到目前为止,对二阶效应的研究多见于钢框架和组合结构。在我国现有规范中,当钢筋混凝土框架的刚重比满足一定条件时,可以不考虑二阶效应的影响。然而近场地震下,会对结构造成超出预计的影响,有必要考虑钢筋混凝土框架结构在近场地震下二阶效应的影响。针对这些问题,本文进行了以下几方面的研究：1.介绍了近场地震的危害性以及近场地震的特点、框架结构的二阶效应以及相关的设计分析方法、结构抗震弹塑性方法。2.对一个高层钢筋混凝土框架在三组地震记录下进行弹塑性动力时程分析。对比发现近场地震增大了结构对基底剪力、顶点位移和层间位移角的需求,并放大了结构的残余变形。其中,脉冲地震的影响更为显著。并且随着地震动峰值的增加,层间位移角和顶点位移的这种放大作用逐渐增大。二阶效应增大了结构的顶点位移最大值和层间位移角最大值,减小了结构的基底剪力最大值。这种影响随着加速度峰值的增大而增大。其中,近场脉冲地震动的影响依次大于近场非脉冲地震和远场地震。在三类地震动作用下,二阶效应均放大了结构的残余顶点位移反应以及残余层间位移角反应,其中近场脉冲地震的影响依次大于近场非脉冲地震和远场地震。3.阐述了增量动力分析以及易损性分析的原理,并对一个高层钢筋混凝土框架进行IDA分析,得到了结构的IDA曲线以及易损性曲线,与危险性曲线相结合,得到了结构在各个极限状态的年平均超越概率,并得到了二阶效应对结构IDA结果的影响。更多还原

【Abstract】 Recently, both foreign and domestic scholars have researched extensively about near-field earthquake and the second order effect. But until now the most researches are about the steel frames and combinated structures. The second order effect can be neglected in our current code if the ratio of stiffness to weight satisfies certain condition when referring to the reinforced concrete frame. Nevertheless, suffering with near-field earthquake, the structure will act beyond common imagination. So the consideration of the second order effect of the reinforced concrete frame under near-field earthquake is necessary. Focused on these problems, this thesis involves the following work:1. The hazard and the characteristics of near-field earthquake is introduced, and then, the second order effect and the related design methods is summarized. Two kind of elasto-plasitc analysis method are compared.2. With the method of nonlinear time history analysis, the behavior of a tall reinforced concrete frame is studied under the action of far-field ground motions and near-field ground motions with pulse and without. It is found that the requirement of base shear, top displacement and story drift is magnified under near-field earthquake. This phenomenon is more remarkable under the pulse ground motion. With the PGA becomes larger, this amplification effect increase. The second order effects enlarge the requirement of top displacement and story drift and diminish that of base shear. This influence goes big when the PGA arises. The effect under near-field earthquake with pulse is more prominent than near-field earthquake without pulse and far-field earthquake by sequence. The similar phenomenon appears on the residual top displacement and the residual story drift of the structure.3. The theory of the incremental dynamic analysis and the vulnerability analysis is described in this paper. The IDA curves and the vulnerability curves are taken from the analysis of a tall reinforced concrete frame. Combined with the seismic hazard curve, the MAF of the structure’s each limit state can be calculated. Also, the influence of the second order effect on the IDA results is obtained.更多还原