【作者】 杨大彬；

【导师】 张毅刚；

【作者基本信息】 北京工业大学 ， 土木工程， 2011， 博士

【摘要】 基于性能的抗震分析与设计是工程抗震发展史上的一个重要里程碑,代表了抗震研究的发展方向。在多高层建筑结构领域,基于性能的抗震研究已经取得了比较丰硕的理论成果,在抗震设计规范中已经有了一些体现。然而目前基于性能的空间结构抗震研究还处于初步的理论探索阶段,远未形成具体有效的设计方法,相比于多高层建筑结构,其理论研究大大滞后,严重制约了空间结构进一步的应用与发展。本文以空间结构的一种形式——纵边落地支承单层柱面网壳为主要研究对象,进行了基于性能的抗震理论研究,主要研究内容及成果如下:(1)空间结构地震时程分析Rayleigh阻尼系数的研究基于结构在单维地震动下的振型峰值应变能公式,结合空间结构自振特性及地震响应的统计分析及规律总结,引入合理简化条件,首次推导了空间结构在三维地震动下的振型峰值应变能系数近似公式,该系数是空间结构三维地震动下各振型贡献的合理度量系数。以此系数为权重,提出了基于多参考振型的加权最小二乘法计算空间结构Rayleigh阻尼系数,基于Rayleigh阻尼理论的基本原理和假设条件,以纵边落地支承单层和双层柱面网壳为典型算例,对Rayleigh阻尼系数传统计算方法和本文提出的新方法进行了对比分析。分析表明,传统方法在某些地震波作用下会导致较大误差,而在任意地震波作用下新方法的结果都比传统方法更为合理,因此该方法是空间结构地震时程分析Rayleigh阻尼系数通用合理的计算方法。(2)纵边落地支承单层柱面网壳强震倒塌机理研究采用基于荷载域全程响应分析方法首次对纵边落地支承单层柱面网壳强震倒塌机理进行了系统研究。研究表明,该类型柱壳呈现明显的沿跨度方向的单向受力特征,当长宽比大于1时,长宽比对其受力几乎没有影响;强震破坏均为动力强度破坏;最低阶特征值屈曲模态和最低阶振动模态都可以作为初始几何缺陷分布模式,这两种分布模式对柱壳的地震响应几乎没有影响;初始几何缺陷方向对其地震响应有显著影响,因此地震响应分析必须考虑两个方向的初始几何缺陷;矢跨比对其倒塌PGA的发展趋势并无固定的影响规律;倒塌PGA均随屋面附加恒荷载的增大而减小,其减小程度随柱壳不同而不同。(3)单层网壳地震损伤评估方法研究提出了基于静力稳定极限承载力退化的单层网壳地震损伤评估方法。该方法理论基础及分析过程合理,计算简单且易于实现。利用该方法对纵边落地支承单层柱面网壳进行了损伤评估,并对该方法在单层球面网壳中的应用进行了研究。结果表明,该方法能够以较高的精度对单层网壳的地震损伤尤其是临近倒塌时的损伤进行评估,是单层网壳地震损伤评估的合理方法。该方法得到的损伤指数可以用来衡量单层网壳的性能水平,解决了基于性能的单层网壳抗震分析中的一个关键问题。(4)纵边落地支承单层柱面网壳地震动参数研究首次系统研究了在近场地震动下纵边落地支承单层柱面网壳的损伤和常用地震动参数的相关性和有效性。结果表明,由于该类型柱壳沿跨度方向的单向受力特性明显,整体角度来看,跨度方向的地震动参数的相关性和有效性高于其他两个方向的地震动参数;沿跨度方向地震动在结构基本周期处的加速度谱值Sa(T1)是最为合理的地震动参数,而PGA并非合适的地震动参数。该部分研究可以为纵边落地支承单层柱面网壳基于概率的抗震性能评估奠定基础。(5)纵边落地支承单层柱面网壳性能水平划分和抗震性能评估研究以《建筑地震破坏等级划分标准》(建设部90建抗字377号)给出的性能水平为基础,结合纵边落地支承单层柱面网壳的地震响应特点,利用基于静力稳定极限承载力退化的地震损伤指数对该类型柱壳的性能水平进行了划分,给出了不同性能水平下结构的破坏特征;依据基于概率的结构抗震性能评估方法对矢跨比为1/4的典型纵边落地支承单层柱面网壳进行了抗震性能评估,计算了某场地下各性能水平的年均超越概率和设计基准期50年的超越概率,结果表明,该柱壳具有很好的抗震性能。更多还原

【Abstract】 As a milestone in engineering seismic research, performance-based seismic research has become the developing trend in seismic research. A lot of theoretical research results have been acquired regarding multi-story buildings, some of which have been implemented in the designing code. While the performance-based seismic research about spatial structures is just at the beginning, far away from forming the effective designing method. The research status in spatial structures is far behind that of multi-story buildings, which severely restricts the application and development of spatial structures. As one kind of spatial structures, single-layer cylindrical latticed shell with longitudinal edge ground supported is taken as the main research object, the performance-based seismic analysis of which is performed in the paper, and the main research contents and results is as follows:(1) Research of Rayleigh damping coefficients in seismic time-history analysis of spatial structuresBased on the maximum strain energy ratio of modes under one dimensional seismic excitation, considering the characteristics of natural vibration and seismic response of spatial structures, the approximate maximum strain energy ratio of modes under three dimensional seismic excitations are firstly deduced with the rational simplifications in the equation, which can quantify the modal contribution of spatial structures under three dimensional seismic excitations. With it as the weight, a multi-mode based weighted least square method is proposed to compute the Rayleigh damping coefficients of spatial structures. Based on the basic theory and assumptions of Rayleigh damping theory, with single-layer and double-layer cylindrical latticed shell with longitudinal edge ground supported as the examples, the comparison between the traditional method and the new method is performed. The results show that, significant error will be induced when the traditional method is used under some ground motions, and the results of the new method are better than those of the traditional method under all the ground motions, so the new method is the general and rational method to compute the Rayleigh damping coefficients in seismic time-history analysis of spatial structures.(2) Research of collapse mechanism of single-layer cylindrical latticed shell with longitudinal edge ground supported under severe earthquakes The collapse mechanism of single-layer cylindrical latticed shell with longitudinal edge ground supported under severe earthquakes are studied with the full-range responses analysis method based on load domain. The results show that, it has very distinct one way mechanical characteristics along the span direction, so the length to width ratio has little influence on the mechanical characteristics, and all the failure modes under severe earthquakes are of the dynamic strength failure kind, and it makes little difference with the basic eigenvalue buckling mode or the basic natural vibration mode as the initial geometrical imperfection, so both can be the initial geometrical imperfection, and the initial geometrical imperfection direction has a great influence on its dynamic response, so both the directions should be considered in seismic response analysis, and the rise to span ratio has no fixed influence pattern on the collapse PGA, and the collapse PGA will decrease with the increase of roof super dead load, but the magnitude of which varies with the shells.(3) Research of seismic damage assessment method of single-layer latticed shellsThe seismic damage assessment method of single-layer latticed shells based on degradation of static stability capacity is proposed. The method has a solid theoretical basis and rational analysis process, and it can be easily implemented. Its application in single-layer cylindrical latticed shell with longitudinal edge ground supported and single-layer latticed dome are studied, and the results show that the method has a high precision especially when the shells near collapse, so it is a rational method in damage assessment of single-layer latticed shells. And the method can be used to quantify the seismic performance levels of single-layer latticed shells, which is a key problem in performance-based seismic analysis of single-layer latticed shells.(4) Research of ground motion intensity measures for single-layer cylindrical latticed shell with longitudinal edge ground supportedThe correlation and effectiveness of ground motion intensity measures for single-layer cylindrical latticed shell with longitudinal edge ground supported under near source ground motions are systematically studied for the first time. And the results show that, since this kind of shell takes on very distinct mechanical characteristics along span direction, the intensity measures of ground motions in span direction have stronger correlation and effectiveness than those in other directions on the whole, and the acceleration spectrum at basic period Sa(T1) is the most appropriate intensity measure while PGA is not. This research result can provide the basis for the probability-based seismic performance assessment of this kind of shells. (5) Research of performance level classification and seismic performance assessment for single-layer cylindrical latticed shell with longitudinal edge ground supportedBased on the performance levels given by <Classification criterion for seismic damage states of building>, considering the seismic response characteristics of single-layer cylindrical latticed shell with longitudinal edge ground supported, the seismic performances are quantified with the damage index based on the degradation of static stability capacity, and the damage characteristics under each performance levels is given. The seismic performance of the shell with the rise to span ratio of 1/4 is evaluated with the probability-based seismic performance assessment method, and the exceedance probability in one year and design reference period of 50 years for each performance levels are calculated, which shows that the shell has a high seismic performance.更多还原