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1.
大震下被动与智能隔震结构动力可靠度的对比 总被引：9，自引：0，他引：9
对被动及智能隔震结构在“大震”条件下的动力可靠度进行探讨。将被动及智能隔震体系均取作弹塑性模型,并用退化Bouc-W en滞变模型描述上部结构的恢复力,用非退化Bouc-W en模型描述隔震层的恢复力。采用虚拟激励法计算结构的随机响应,根据我国抗震规范中“大震不倒”的设防目标,采用各层最大层间位移峰值响应和累积滞变耗能构造双参数的随机疲劳累积损伤指数,作为功能状态指标。假定各层失效相关,用串联系统计算体系动力可靠度。通过数值算例,对比了被动隔震、智能隔震与非隔震体系的条件失效概率,从动力可靠度角度显示了智能隔震体系的减震优势。 相似文献
2.
选用胡聿贤平稳地震地面运动模型作为基础隔震结构的随机地震动输入,采用Bouc-Wen模型描述隔震结构的层间滞变位移,将滞变体系动力特性矩阵随机等效线性化,并建立等价线性状态方程。引入左右特征向量系,对振动微分方程进行解耦,推导了基础隔震结构随机地震响应的统计矩解析解。采用变形失效准则,定义了上部结构和隔震层的功能状态极限函数。在此基础上,采用首次超越破坏模型,基于Possion分布假设和串联系统可靠度模型,建立了从整体上评价基础隔震体系抗震可靠度的简化分析方法。最后,通过一个基础隔震框架结构计算实例,说明了这种方法的运用。 相似文献
3.
建立了多级串联非比例阻尼隔震结构动力分析模型;引用分区瑞利阻尼模型将非比例阻尼矩阵分解为瑞利阻尼矩阵和体现非比例阻尼的余项阻尼矩阵,推导出结构的阻尼矩阵;并编制了MATLAB动力时程分析程序,对一实际隔震工程进行地震响应分析.结果表明:随着下部结构刚度的增加,结构的层剪力比和隔震层位移响应峰值均趋向于基础隔震结构的对应值;当下部结构为一层,且层间刚度大于上部结构底层层间刚度4～6倍时,可以近似按基础隔震结构进行动力分析. 相似文献
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《华南地震》2016,(4)
层间隔震结构是基础隔震结构的发展与延伸,作为一种复杂结构体系,基础隔震结构的工作机理不一定完全适合,延长结构的周期可能无法同时降低上、下部结构的地震响应。此类体系以往的理论及试验研究,隔震层的阻尼多由铅芯橡胶支座提供,采用天然橡胶支座及黏滞阻尼器作为隔震层,进行了层间隔震结构振动台试验研究。设计了一个4层的钢框架模型,依次进行了基础固接、基础隔震、1层顶隔震、2层顶隔震及3层顶隔震的振动台试验研究,测定结构的加速度、层间位移及层剪力系数。试验结果表明:黏滞阻尼器层间隔震结构具有良好的减震效果。建立了层间隔震结构的有限元模型,将有限元分析结果与试验结果进行了对比。 相似文献
6.
在隔震结构Benchmark模型的基础上,建立了相应的动力反应计算方法及计算程序,并在理想化隔震层刚度布置的情况下研究了隔震层水平刚度分布对基础隔震结构地震响应的影响.通过针对Benchmark模型设计的3种隔震方案的计算结果比较表明:当隔震层刚度中心靠近结构质心时,能显著降低结构的扭转反应,但同时增大了水平位移分量.文中在隔震结构Benchmark模型上建立的计算方法和结论为隔震体系计算和隔震方案设计提供了可靠的依据和途径. 相似文献
7.
为了研究铅芯橡胶隔震支座的阻尼分布对平扭耦联隔震体系隔震效果的影响,本文对一个三层两跨钢框架,通过调整上部结构负重块位置及下部铅芯橡胶隔震支座的分布位置,进行不同偏心工况下平扭耦联隔震体系地震模拟振动台试验,获得了不同偏心工况、不同阻尼分布情况下结构位移和加速度的时程曲线。试验和分析表明:隔震层阻尼中心与上部结构的质心位置接近,或者增大隔震层的阻尼半径,可显著地降低上部结构的扭转反应。 相似文献
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考虑耦联影响的二次结构体系减震分析 总被引：1，自引：2，他引：1
建立了基础隔震的主次结构体系耦联运动方程，开发了动力分析程序PS—BASE．FOR，对一典型结构的二次结构绝对加速度反应谱与相对位移反应谱计算分析表明，主体结构隔震或同时增大二次结构阻尼，是取得二次结构较好抗震性能的有效途径，增大主体结构的隔震阻尼对二次结构略有不利影响。 相似文献
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本文对一基础隔震模型进行了软着陆保护振动台模拟地震动试验,展示了该隔震体系在发生水平向大变形条件下,在不同后备支座以及滑移面摩擦系数不同情况下,轴压力从承载支座向后备支座转移的情况。结果表明:软着陆隔震保护体系不仅保护了承载支座免遭大变形失稳破坏,同时还能提供摩擦阻尼,将隔震层位移和上部结构层间位移控制在允许范围内。文中对隔震层位移、上部结构最大层间位移及绝对加速度等进行了分析,所得理论曲线与试验拟合曲线吻合较好。具有很大的应用前景。 相似文献
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RC框架结构薄弱层的层间位移可靠度水平考察 总被引：2，自引：0，他引：2
讨论了钢筋混凝土框架结构层间极限变形角的近似概率特性,考察了大震作用下20余幢钢筋混凝土框架结构薄弱层的层间位移可靠度水平,从而为直接基于位移可靠度的抗震设计中层间目标位移可靠度的确定提供了一定依据。 相似文献
12.
Rachel L. Calafell Paul N. Roschke Juan C. de la Llera 《Bulletin of Earthquake Engineering》2010,8(4):1019-1036
In this study friction pendulum system (FPS) bearings and precast-prestressed pile (PPP) isolators are considered as base
isolation devices for a Chilean confined masonry house. The house is numerically modeled using a multiple degree-of-freedom
approach that is calibrated with experimental data. Dynamic behavior of the FPS and PPP isolators is simulated using analytical
formulations based on laboratory testing. Optimization of the isolators is performed using an earthquake that is generated
to match the design spectrum for the house based on Chilean seismic code. A non-dominated sorting genetic algorithm (NSGA-II)
is applied to carry out the optimization. Seismic response of the base-isolated structure subjected to a suite of ground motions
is compared to the performance of the traditionally-constructed structure by means of several performance indices (PIs). Numerical
simulations indicate that the PPP isolation system is more effective in reducing the base and structural shear, interstory
drift, and floor acceleration of the structure than the FPS isolation system, although both systems result in substantial
reductions of the response. 相似文献
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基于动力可靠度的隔震结构参数模糊优化 总被引：1，自引：0，他引：1
分别选取Bouc—Wen和退化Bouc—Wen模型描述隔震层及上部结构滞变回复力，采用虚拟激励法进行隔震结构随机响应分析。用各层最大层间位移响应和累计疲劳损伤指数建立双参数的功能状态方程，用一次二阶矩理论计算隔震结构失效概率。选用一个隔震框架作为数值算例，探讨了低频过滤器、隔震阻尼比和隔震刚度对隔震结构各子系统条件失效概率的影响。建立了隔震结构参数多目标优化模型，用失效概率确定单因素评判的隶属度，并采用最大隶属度法对隔震参数进行模糊优化。 相似文献
15.
Shear building representations of seismically isolated buildings 总被引：2，自引：0，他引：2
Seismic isolation, with its capability of reducing floor accelerations and interstory drifts simultaneously, is recognized
as an earthquake resistant design method that protects contents of a building along with the building itself. In research
studies, superstructures of seismically isolated buildings are commonly modeled as idealized shear buildings. Shear building
representation corresponds to an idealized structure where the beams are infinitely stiff in flexure and axially inextensible;
columns are axially inextensible; and rigid floors are supported on these columns. Although it is more convenient to model
and analyze a shear building, such an idealization may influence the seismic responses of seismically isolated buildings.
This study presents a comparison of the seismic performances of seismically isolated buildings with superstructures modeled
as shear buildings to those with full three dimensional superstructures. Both linear and nonlinear base isolation systems
with different isolation periods and superstructures with different number of stories are considered. 相似文献
16.
《地震工程与结构动力学》2018,47(5):1169-1192
In seismic base isolation, most of the earthquake‐induced displacement demand is concentrated at the isolation level, thereby the base‐isolation system undergoes large displacements. In an attempt to reduce such displacement demand, this paper proposes an enhanced base‐isolation system incorporating the inerter, a 2‐terminal flywheel device whose generated force is proportional to the relative acceleration between its terminals. The inerter acts as an additional, apparent mass that can be even 200 times higher than its physical mass. When the inerter is installed in series with spring and damper elements, a lower‐mass and more effective alternative to the traditional tuned mass damper (TMD) is obtained, ie, the TMD inerter (TMDI), wherein the device inertance plays the role of the TMD mass. By attaching a TMDI to the isolation floor, it is demonstrated that the displacement demand of base‐isolated structures can be significantly reduced. Due to the stochastic nature of earthquake ground motions, optimal parameters of the TMDI are found based on a probabilistic framework. Different optimization procedures are scrutinized. The effectiveness of the optimal TMDI parameters is assessed via time history analyses of base‐isolated multistory buildings under several earthquake excitations; a sensitivity analysis is also performed. The enhanced base‐isolation system equipped with optimal TMDI attains an excellent level of vibration reduction as compared to the conventional base‐isolation scheme, in terms not only of displacement demand of the base‐isolation system but also of response of the isolated superstructure (eg, base shear and interstory drifts); moreover, the proposed vibration control strategy does not imply excessive stroke of the TMDI. 相似文献
17.
Viscoelastic dampers (VEDs) are one of the most common passive control devices used in new and retrofit building projects which reduce the structure responses and dissipate seismic energy during an earthquake. Various methods to design this kind of dampers have been proposed based on the desired level of additional damping, eigenvalue assignment, modal strain energy, linear quadratic regulator control theories, and other approaches. In the current engineering practice, the popular method is the one based on the modal strain energy that uses the inter-story lateral stiffness as one of the main variables for damper design. However, depending on the configuration of the structure, in some cases the resulting interstory lateral stiffness can be very large. Consequently, the dampers size would also be large producing much more damping than that effectively necessary, resulting in an increase of the overall cost of the supplemental damping system and causing excessive stress on the structural elements connected to the dampers. In this paper an alternative practical design method for structures with VEDs is proposed. This method uses the inter-story shear forces as one of the main variables to accomplish the damper design compared to what was done in previous studies. Nonlinear time-history analyses were conducted on a 7-story reinforced concrete (RC) structure to check the reliability and effectiveness of the proposed method. Comparisons on the seismic performance between the structure without dampers and that equipped with VEDs were carried out. It is concluded that the proposed method results in a very suitable size of dampers, which are able to improve the performance of the structure at all levels of earthquake ground motions and satisfying the drift requirement prescribed in the codes. 相似文献
18.
Optimal energy‐based seismic design of non‐conventional Tuned Mass Damper (TMD) implemented via inter‐story isolation 
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下载免费PDF全文 Inter‐story isolation, an effective strategy for mitigating the seismic risk of both new and existing buildings, has gained more and more interest in recent years as alternative to base isolation, whenever the latter results to be impractical, technically difficult or uneconomic. As suggested by the name, the technique consists in inserting flexible isolators at floor levels other than the base along the height of a multi‐story building, thus realizing a non‐conventional Tuned Mass Damper (TMD). Consistent with this, an optimal design methodology is developed in the present paper with the objective of achieving the global protection of both the structural portions separated by the inter‐story isolation system, that is, the lower portion (below the isolation system) and the isolated upper portion (above the isolation system). The optimization procedure is formulated on the basis of an energy performance criterion that consists in maximizing the ratio between the energy dissipated in the isolation system and the input energy globally transferred to the entire structure. Numerical simulations, performed under natural accelerograms with different frequency content and considering increasing isolation levels along the height of a reference frame structure, are used to investigate the seismic performance of the optimized inter‐story isolation systems. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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层间隔震结构是由基础隔震结构发展而来的一种新型隔震结构。为研究层间隔震结构的倒塌,需先研究不同层间隔震结构的不同失效模式和失效位置,文章建立了3个不同结构参数的层间隔震结构有限元模型,选取20条与抗震规范反应谱吻合的地震动,采用增量动力分析（IDA）方法,分别对其失效模式和失效位置进行研究。研究表明:基于不同的结构参数,层间隔震的基本失效模式有三种,即隔震层水平位移超限导致结构失效、下部结构层间位移角超限导致结构失效、隔震层拉压应力超限导致结构失效;隔震层下部结构和隔震层最外边缘支座为结构的薄弱位置,应引起更多关注。此方法不仅可以研究结构的不同失效模式,还可以确定失效位置,可为下一步层间隔震结构的抗倒塌分析提供理论基础。 相似文献
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利用基于性能的结构可靠度分析方法,对基础隔震钢筋混凝土框剪结构进行分析研究。选取20条实际地震动记录,以0.2g为步长对结构地震动参数PGA进行调幅后,建立了140个结构-地震动样本空间。选取上部结构的最大层间位移角、隔震层位移为量化指标,对每一个样本进行动力非线性时程分析后,将结构响应进行统计得到结构在各地震动强度下超越极限破坏状态的概率,将其绘制成基础隔震钢筋混凝土框剪结构的易损性曲线并利用整体可靠度方法分析结构发生倒塌的可靠度指标。该方法直观地反映了结构发生倒塌的概率,为结构的地震损失评估提供依据。 相似文献