【作者】 李成；

【导师】 顾强；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2008， 博士

【摘要】 大量的震害分析和试验研究表明:在强震作用下,建筑结构通常会表现出非弹性性能。大部分国家抗震规范利用结构延性,采用结构影响系数对设防烈度下的弹性反应进行折减,以此作为结构设计时的地震作用。因此,结构影响系数的取值大小直接关系到结构抗震的安全性与经济性。我国现行抗震规范对不同材料的所有结构体系采用单一的结构影响系数,而没有区分结构形式,这种方法不能够充分体现钢结构体系较好的延性和耗能能力,因此,有必要对钢结构的结构影响系数进行系统的研究。首先,为了解多层钢框架在水平荷载作用下的荷载—位移关系并验证有限元分析,对一榀三层单跨钢框架结构进行了静力推覆试验,试验表明:钢框架结构具有良好的延性性能;有限元模拟与试验结果吻合较好。其次,基于静力推覆分析,对多层钢框架的结构影响系数和位移放大系数进行了系统的分析。分别采用水平均匀分布力和倒三角分布力加载模式对不同层数和跨数的钢框架结构进行了静力推覆分析(Pushover),并得到了结构的能力曲线,在此基础上,应用改进的能力谱法,以规范反应谱为基础建立设防烈度和罕遇烈度下的弹塑性需求谱,确定出结构在设防烈度和罕遇烈度下的目标位移,进而求解出结构的延性折减系数、超强系数、结构影响系数和位移放大系数等参数;同时,分析了不同加载模式、层数和跨数等对各系数的影响。另外,基于增量动力分析(IDA),对多层钢框架结构的结构影响系数和位移放大系数进行了分析。采用梁壳单元相结合的有限元模型进行弹塑性时程分析,得到结构的基底剪力与顶点位移关系包络曲线,以此为基础,求出结构的结构影响系数和位移放大系数,并与Pushover方法的分析结果进行了分析比较。本文系统地分析了多层抗弯钢框架的结构影响系数和位移放大系数。对于修订国家相关规范、指导工程设计有重要的参考价值,也为进一步研究此结构体系的抗震性能打下良好基础。更多还原

【Abstract】 Large earthquake disaster analysis and experimental research indicate that building structure can enter elastic-plasticity in strong motion earthquake.Utilizing ductility of structure,the major seismic codes reduce elastic force of design intensity by the structural influencing coefficient to get design earthquake action in structural design.So,the security and economy of structure design lie on the value of structural influencing coefficient.The single structural influencing coefficient is nowadays adopted by currently Code for seismic design of buildings in all structural systems built by different materials in our country.So the good ductility and energy-dissipating capability of steel structure cannot be fully reflected according to this kind of method,and it is necessary to the structural influencing coefficient to carry on systematic research.Firstly,in order to obtain the load versus displacement curve of moment-resisting frame (MRF) under horizontal force and verify finite element analysis,the static pushover test was conducted on a moment-resisting frame of three-story and one-bay.The result of test showed MRF has good ductility performance,and result of finite element simulation have a good agreement with those of experiment.Secondly,based on the static Pushover analysis,the structural influencing coefficient and displacement amplification factor in multi-story moment-resisting steel frames are carried on systematic analysis.Adopting the model of uniform load and triangular load separately,MRFs of different story numbers and bay numbers are analyzed by static Pushover analytical method,and the global capacity envelopes are obtained.Then,through a method for establishing the inelastic demand spectrum of design intensity and rare intensity based on elastic spectrum of seismic design code for buildings,the structural target displacement of design intensity and rare intensity are estimated by improved capacity spectrum method.The corresponding structural ductility reduction factor,the overstrength factor,the structural influencing coefficient and displacement amplification factor are determined.Meanwhile,the impact on every coefficient of the mode of load,story numbers and span numbers are discussed.In addition,based on incremental dynamic analysis(IDA),the structural influencing coefficient and displacement amplification factor in multi-story moment-resisting steel frames are studied.According to the combination of non-linear shell element and beam element,inelastic time history are performed on steel frames to get the base shear versus top displacement envelope curve.Then,the structural influencing coefficient and displacement amplification factor are calculated and compared with the analysis result of Pushover method.All in all,the structural influencing coefficient and displacement amplification factor in multi-story moment-resisting steel frames are analyzed systematically,which might be useful for revising design code,guiding engineering design and lay the good foundation for further research seismic behavior of moment-resisting steel frames.更多还原