高层建筑变刚度隔震技术试验研究

发布时间：2018-06-07 19:29

本文选题：基础隔震 + 变刚度组合隔震　；参考：《中国建筑科学研究院》2013年博士论文

【摘要】：良好的隔震支座性能是实现隔震设计的关键,研发具有变刚度特性的隔震支座以适应多遇地震和罕遇地震不同阶段的刚度需求对于实现最优的隔震设计具有十分重要的意义。隔震设计目标为多遇地震降低地震作用,罕遇地震控制隔震层变形和支座内力,而橡胶隔震支座和摩擦滑板支座均只具有逐渐降低或单一的水平刚度特性其难以满足上述内容中不同阶段的刚度需求。隔震设计时小震和罕遇地震阶段分别采用橡胶支座水平剪切变形为100%和250%(或对应位移)时所对应的剪切刚度,普通橡胶支座水平刚度通常随剪切变形增加明显下降,而罕遇地震时更为重要的是控制隔震层不产生过大变形同时隔震支座不发生明显受拉,因此,隔震支座在大位移时刚度降低过多不利于隔震层位移控制,隔震设计时如按罕遇地震时所需求刚度进行设计可能会因初始刚度过大导致减震效果大幅降低,由此可知,这两个阶段的隔震层刚度需求存在一定的矛盾。为此,本论文开发了两种具有变刚度特性的隔震支座：其一为串联组合隔震支座,该种支座具有小震时较小水平刚度(小于组合支座中较小支座的水平刚度),到中震或设计设定目标时支座刚度上升,其水平刚度值等于组合支座中较大支座的刚度,从而实现了小震时组合支座具有较小刚度同时具有优秀的隔震效果,当到中、大震作用时,组合支座的水平刚度上升实现了降低隔震层和上部结构整体位移的目标；其二为并联组合隔震支座,该支座兼有橡胶支座(普通支座或铅芯支座)刚度特性和摩擦板的滑移耗能特性,初始阶段并联组合支座水平刚度由内支座提供,外摩擦板提供阻尼特性,到达中、大震或设定目标时,组合支座水平刚度由内、外环支座共同提供,其值将明显上升；并联支座在整个运动过程中竖向荷载均由内外支座共同承担,其竖向承载能力大幅优于相同水平刚度的普通支座,这类支座在裙房等大底盘隔震建筑中具有非常好的适用性。论文中首先对上述两种变刚度隔震支座进行了足尺拟静力试验研究,进而完成了高层隔震结构振动台试验,并针对振动台试验模型进行了弹性及动力弹塑性分析。综合以上研究,本论文的创新工作和研究成果如下： 1.研发并设计完成了具有串联变刚度特性的组合隔震支座,完成了多组足尺试验研究。试验研究表明,串联组合隔震支座具有良好的力学特性,其在变刚度前水平剪切刚度与组合支座中较小支座更为接近,变刚度后组合支座水平刚度主要取决于组合支座中的大支座。串联组合支座竖向刚度可以取两组合支座串联计算值,试验表明理论计算值与试验值十分接近。 2.研发并设计完成了并联组合隔震支座,该种支座具有水平变刚度、铅芯耗能、摩擦耗能特性,同时比相同水平剪切刚度的普通支座具有更高的竖向承载能力。初始变形阶段组合支座水平刚度仅由内部小支座提供,外环支座可自由滑动,在此阶段外环摩擦板起摩擦耗能作用。到达设定位移目标后,内、外环支座共同提供水平刚度,摩擦板相对静止。试验表明并联组合支座具有良好的变刚度和阻尼特性,同时其在整个运动过程中内外环支座可以共同承担竖向荷载。 3.深入归纳总结了隔震支座力学分析模型的适用性及技术特点,根据变刚度支座试验结论拟合了适用于串联和并联变刚度隔震支座的计算滞回模型。 4.设计完成了三组缩尺比例1：10、原形结构为16层的钢筋混凝土框架结构振动台试验。三组模型分别采用了串联组合隔震支座、并联组合隔震支座和普通隔震支座。对比研究了三种采用不同隔震支座振动台模型的实际隔震效果和破坏模式,考察了因地震波频谱特性差异和单项、双向地震动输入差异引起的隔震结构反应区别。通过完成国内首例大比例高层钢筋混凝土变刚度隔震框架结构振动台试验,结合试验结果和现象验证了变刚度隔震技术的有效性,并对实际工程应用提出了设计建议。 5.根据振动台试验结果,完成了针对试验模型的弹性时程和弹塑性时程分析。对比研究了弹性及动力弹塑性分析结果,其中弹性分析基于隔震层非线性变形、上部结构弹性变形的空间三维模型,动力弹塑性分析梁、柱单元基于纤维模型,上部结构在计算中考虑了材料非线性、几何非线性和施工模拟等因素,隔震层考虑了隔震支座非线性变形特性,以上两种计算模型中变刚度隔震支座均采用论文中拟合的滞回模型,通过计算分析与振动台试验结果进行了对比,重点考察了隔震层、隔震支座和上部结构整体反应情况,最终验证了论文中拟合的组合隔震支座计算滞回模型的实际效果。
[Abstract]:The performance of good isolation bearing is the key to the design of seismic isolation. It is of great significance to develop a isolation bearing with variable stiffness characteristics to adapt to the different stages of earthquake and rare earthquake. It is of great significance to achieve optimal isolation design. The deformation of the seismic layer and the support internal force, and the rubber isolation bearing and the friction plate bearing only have the characteristics of gradual reduction or single horizontal stiffness. It is difficult to meet the requirements of the different stages of the above content. The horizontal shear deformation of rubber bearing is 100% and 250% (or corresponding displacement) in the small earthquake and rare earthquake phase of the seismic isolation design. For the corresponding shear stiffness, the horizontal stiffness of ordinary rubber bearing usually decreases with the increase of shear deformation, while the more important is to control the seismic isolation layer without excessive deformation and the isolation bearing does not occur obviously. Therefore, the stiffness reduction of the isolation bearing in the large displacement is not conducive to the displacement control of the isolation layer and the isolation. The design of the required stiffness in the design of a rare earthquake may result in a large reduction in the damping effect of the initial stiffness. Thus, there is a certain contradiction between the stiffness requirements of the two stages of isolation. Therefore, two types of isolation bearings with variable stiffness characteristics are developed in this paper: one is a series composite isolation bearing. The small horizontal stiffness of the seed bearing is smaller than that of the smaller support in the combined support. The stiffness of the support is increased when the base earthquake or the design target is set, and the horizontal stiffness is equal to the stiffness of the larger support in the composite support. In the case of large earthquakes, the horizontal stiffness of the composite support is raised to achieve the goal of reducing the overall displacement of the isolation layer and the superstructure, and the second is the parallel composite isolation bearing, which has the stiffness characteristics of the rubber bearing (common support or lead support) and the slip energy characteristics of the friction plate, and the horizontal stiffness of the parallel composite bearing at the initial stage. Provided by the inner support, the external friction plate provides damping characteristics, when the arrival, the large earthquake or the setting of the target, the horizontal stiffness of the composite support is provided together by the inner and outer ring supports, and the value will rise obviously. The vertical load of the parallel bearing is shared by the internal and external bearings in the whole movement process, and its vertical bearing capacity is much better than the same horizontal stiffness. This kind of support has very good applicability in the large chassis isolation building, such as the podium. In this paper, the full scale pseudo static test is carried out on the two kinds of variable stiffness base isolation bearings, and the shaking table test of the high-rise isolation structure is completed, and the elastic and dynamic elastoplastic analysis of the shaking table test model is carried out. According to the above research, the innovation and research results in this paper are as follows:
1. we developed and designed a composite isolation bearing with a series of variable stiffness characteristics and completed a multi group full scale test. The experimental study shows that the series composite isolation bearing has good mechanical properties. The horizontal shear stiffness before the variable stiffness is closer to the smaller support in the composite support, and the horizontal stiffness of the composite support is main after the variable stiffness. It depends on the large support in the composite support. The vertical stiffness of the series composite supports can be calculated in series with two combination bearings. The experimental results show that the theoretical calculation value is very close to the test value.
2. the parallel composite isolation bearing has been developed and designed. The support has a horizontal stiffness, lead core energy dissipation and friction energy dissipation characteristics. At the same time, it has higher vertical bearing capacity than the common bearing with the same horizontal shear stiffness. The horizontal stiffness of the composite support is only provided by small support in the initial deformation stage, and the outer ring supports can slide freely, In this stage, the outer ring friction plate plays a frictional energy dissipation effect. When the displacement target is set, the outer ring support provides the horizontal stiffness together, and the friction plate is relatively static. The test shows that the parallel composite support has good stiffness and damping characteristics, and the inner outer ring bearing can jointly bear the vertical load during the whole movement process.
3. the applicability and technical characteristics of the mechanical analysis model of isolation bearing are summarized, and the calculation hysteretic model suitable for the series and parallel variable stiffness isolation bearings is fitted according to the conclusions of the variable stiffness bearing test.
4. design and completion of three sets of scale ratio at 1:10, the original structure is 16 layers of reinforced concrete frame structure shaking table test. The three groups of models respectively adopt series composite isolation bearing, parallel base isolation bearing and common isolation bearing. Compared and studied the actual isolation effect and failure mode of three kinds of vibration table model with different isolation bearings. By completing the first example of the vibration table test of the first large proportion of high rise reinforced concrete frame structure with variable stiffness, the validity of the variable stiffness isolation technology is verified by the test results and phenomena, and the practical engineering is also verified. The design proposal is put forward in the application.
5. according to the test results of the shaking table, the elastic time history and elastoplastic time history analysis are completed. The elastic and dynamic elastoplastic analysis results are compared. The elastic analysis is based on the nonlinear deformation of the seismic isolation layer, the three-dimensional model of the elastic deformation of the superstructure, the dynamic elastoplastic analysis beam, and the column element based on the fiber model. The superstructure takes into account the factors such as material nonlinearity, geometric nonlinearity and construction simulation, and the seismic isolation layer takes into account the nonlinear deformation characteristics of the isolation bearing. The variable stiffness isolation bearing in the two models are all fitted with the hysteresis model in the paper, and the results are compared with the results of the shaking table test by the calculation and analysis. The overall response of the isolation layer, the isolation bearing and the upper structure is verified, and the actual effect of the hysteretic model calculated by the combined base isolation bearing is verified.
【学位授予单位】：中国建筑科学研究院
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU973.31

【参考文献】