【作者】 赵耀；

【导师】 赖明； 李英民；

【作者基本信息】 重庆大学 ， 土木工程， 2011， 硕士

【摘要】 掉层结构是山地建筑结构的典型代表之一,在山地城市中被广泛应用。在2008年5.12汶川地震中,都江堰某小区山地建筑结构表现出较为严重的破坏。目前掉层结构的特殊性还没有得到充分的认识,工程设计缺乏相关规范指导,理论研究滞后于工程实践的需要。本文在以往对山地建筑结构抗震性能等研究的基础上,旨在研究掉层结构动力特性以及整体抗倾覆性能,为工程设计提供理论依据,为《山地建筑结构设计规程》的编订提供一定的理论基础。研究的内容主要包括:①基于掉层结构框架体系,提出简化模型;②进行了掉层部分楼层刚度、楼层质量以及楼层层数变化等相关因素对掉层结构动力特性的影响的分析;③在线性地震作用下,分析了相同振型对掉层结构上部楼层和掉层部分楼层反应贡献的差异性;④在倾覆荷载作用下,对掉层结构的基底应力分布规律进行研究;⑤深入探讨了掉层结构整体抗倾覆稳定性的特殊问题所在,并对掉层结构整体抗倾覆性能的变化规律进行研究。通过本文的研究与分析,得到以下主要结论:①利用简化串模型进行了在不同质量和楼层分布下动力特性的分析,发现其动力特性与普通规则结构的动力特性存在显著差异。当掉层部分楼层刚度越小,质量越大以及楼层数量越多,这种差异就越显著。并给出了掉层结构掉层部分楼层刚度、楼层质量及楼层变化对结构固有周期、振型及相关特性(如振型参与系数、振型质量参与系数)带来的影响规律。②在地震作用下,同一振型对掉层结构上部结构楼层以及掉层部分楼层的反应的贡献存在差异,基本振型主要影响上部结构楼层,而高阶振型主要影响掉层部分楼层。③在对结构地震作用下进行分析计算时,目前中国规范要求结构的振型质量参与系数达到90%,此规定要求对掉层结构略显不足,建议可相应提高。④根据掉层结构基底应力分布规律的研究,目前中国规范关于结构整体抗倾覆的规定不适用于掉层结构,建议设计时直接进行掉层结构整体抗倾覆验算;本文给了掉层结构倾覆弯矩和抗倾覆弯矩的计算模型及方法,对于连接式掉层结构需要考虑侧向土压力的影响。⑤对掉层结构整体抗倾覆稳定性能分析表明,掉层结构整体抗倾覆性能与分别按两个接地面起算的规则结构都偏不利;此外,掉层部分的楼层数量越多、跨数越小,掉层结构整体抗倾覆稳定性能越不利。更多还原

【Abstract】 The structure supported by foundation with different horizontal levels (abbreviated as SSFDH in the paper below), which is widely built in mountain cities, is a typical kind of structure built on slope. Such kind of buildings in a community located in Dujiangyan had damaged heavily during the 5.12 Wenchuan Earthquake 2008. The facts are that the specialties in such structures haven’t been full understanding, and the structure designing is lack of the guides of relevant codes, and the theoretical research fall behind the demands of engineering construction.Based on the achievements of previous researches about the seismic behaviors of SSFDH, this paper aims to research the dynamic characteristics and anti-overturning behaviors for the purposes of providing a theoretical basis to the design work and the code compiling. The main contents are as below:①offering the simplified model based on the frame structure in SSFDH;②analyzing the influence to the dynamic characteristics when changing storey stiffness, storey mass and storey numbers and other factors;③analyzing the difference of contribution to the earthquake responses among the upper storeys and lower storeys under the same mode shape;④studying the stress distribution of basement subjected to the lateral load action;⑤discussing the special problems and studying the rules of SSFDH on anti-overturning behaviors. It can be concluded as follows by studying and analyzing in this paper:①There exist significant differences in dynamic characteristics between SSFDH and regular structures by analyzing the dynamic characteristics of simplified model with variation of storey mass, stiffness and storey numbers. The differences become significant while the lower storey stiffness is weaker, lower storey mass and storey numbers are larger. In addition, this paper provided the influence laws to natural period, mode shapes and related properties such as modal participation factors and modal participating mass ratios when changing the influence factors above.②The same mode shape contribute differently to the earthquake response between the upper storeys and the lower storeys. The fundamental mode shape mostly affects the upper storeys while the higher modes mainly affect the lower storeys.③The Chinese codes require the modal participating mass ratios must achieve 90% at least computing and analyzing the structure subjected to earthquake action. For the lower storeys of SSFDH, it might be omit the higher modes’contribution if doing this when designing so that leading to unsafety. The ratio is insufficient for SSFDH.④According to the study on the basement stress distribution, the guidelines in current Chinese codes aren’t suitable for SSFDH in anti-overturning. It suggests checking anti-overturning behavior when designing SSFDH. This paper provides the moment computing method of both overturning and anti-overturning. The earthquake dynamic earth pressure have to be considered for SSFDH which lower storys contact with slope.⑤By analyzing the anti-overturning behavior of SSFDH, it is more unfavorable than the two regular structures which based on the different horizontal levels. Besides, the more stories, the less bays in the lower level, the more unfavorable in the anti-overturning behaviors for SSFDH.更多还原