【作者】 石诚；

【导师】 李英民；

【作者基本信息】 重庆大学 ， 结构工程， 2004， 硕士

【摘要】 考虑双向水平地震共同作用的结构抗震分析与设计是一项涉及双向地震动输入确定、双向地震作用结构范围界定、双向地震效应组合等问题的复杂工作,结构抗震设计中还涉及结构扭转效应的评判控制和偶然偏心的处理等问题。我国现行《建筑抗震设计规范(GB50011-2001)》和《高层建筑混凝土结构技术规程(JGJ3-2002)》对于偶然偏心的考虑、结构扭转效应的评判控制、双向地震作用结构范围的界定、双向地震效应组合方法等问题的相关规定尚存在因研究不充分而值得商榷之处,因此,深入研究双向水平地震共同作用下结构抗震分析与设计的相关问题,具有重要的学术意义和工程应用价值。本文作为科研课题 “双向水平地震共同作用下的结构抗震设计方法研究”的一部分,在前期研究工作的基础上,主要围绕双向水平地震作用结构范围的进一步界定和相应分析设计方法的确立完善,针对偶然偏心问题、结构扭转效应指标、双向水平地震作用下的轴力叠加、双向水平地震效应的组合方法等四方面问题进行了研究,目的在于对规范相关条文的补充修订提供理论和数据基础。通过对国内外相关文献和规范的考查、对比,在理论推导和算例分析的基础上,得出以下主要结论:①现行规范关于特定条件下偶然偏心问题的规定并不十分合理,建议进行抗震设计的结构均计算偶然扭矩计入偶然偏心的影响。②结构相对扭转效应主要受相对偏心距和平扭刚度比两个结构参数共同影响,偏心距和刚度比相同的单双向偏心结构扭转效应并不相同,现行规范限定的平扭周期比不能完全反映结构的平扭刚度比,仅限定结构单方向平扭周期比以控制结构扭转效应的做法有待改进。③双向水平地震共同作用下轴力效应叠加的问题应引起重视,仅考虑单向水平地震作用可能会使某些竖向构件的截面承载力设计偏不安全。考虑双向水平地震作用的结构范围仅局限于现行规范所规定的质量和刚度明显不对称(扭转效应突出)的结构并不十分合理。④现行规范关于双向水平地震作用下结构效应的组合方法可以满足工程设计的精度要求,但双向设计反应谱的完善还有赖于双向地震动输入问题的深入研究。论文最后对规范相关规定的不足提出了改进建议,并对后续研究工作进行了展望。更多还原

【Abstract】 Structural seismic analysis and design considering earthquake actions in two directions simultaneously is a complicated work, which includes the estimate of the input earthquake actions, the definition of the scope of structures considering earthquake actions in two directions and the combination of seismic effect. At the same time, in seismic design, further research is necessary on how to estimate and control the torsion effect and how to consider the accidental eccentricity. Some relative provisions about the above problems have been given in Code for Seismic Design of Buildings (GB50011-2001) and Technical specification for concrete structures of tall building (JGJ3-2002). But those provisions are not based on adequate research, and need to be reviewed or modified. Therefore, further study on seismic analysis and design considering two horizontal orthogonal earthquake actions simultaneously is significant for academic research and engineering design.The subject discussed in this paper is a part of the scientific research project “ Structure seismic design considering two horizontal components of ground motions simultaneously ”. In this paper, further research has been made on the scope of the structures considering earthquake actions in two directions, the combination method of the seismic effect caused by different inputs in two directions and the estimate of the accidental eccentricity and the torsion effect, which aims to offer sufficient theoretical and numerical material for amending the relative provisions in the codes. Moreover, the relative outcome in the different codes and references have been reviewed and compared. Based on the theoretical derivation and the results of model analysis, some conclusions have been got as following,①The provisions about accidental eccentricity in GB50011-2001 and JGJ3-2002 may be not reasonable. It has been suggested the accidental eccentricity should be considered for all the structures in seismic design.②The torsion effect of structures has relations with the relative eccentricity and the ratio of the uncoupled translational stiffness and torsional stiffness. The torsion effect is different for the structures with eccentricity in one and two directions even if the relative eccentricity and ratio of the uncoupled stiffness are same. The ratio of the coupled periods defined in JGJ3-2002 can not exactly reflect the ratio of the uncoupled stiffness. JGJ3-2002 only controls the relative torsion effect in one direction is not <WP=7>reasonable.③The superposed effect of axial force caused by different seismic action inputs in two horizontal directions should be noticed. Omitting the superposed effect of axial force may lead to unsafe design for some columns. The scope of structures considering earthquake actions in two directions should not only be limited in the irregular structures.④The combination method of seismic action effect caused by different inputs in two directions in GB50011-2001 has enough calculation precision for engineering design. However, the relative design response spectra in two orthogonal directions need more research.Finally, some suggestions and measures are put forward for improving the deficiency of relative provisions in GB50011-2001 and JGJ3-2002. The directions of further developing in this field are prospected.更多还原