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1.
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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《地震工程与工程振动》2017,(1)
为检验混凝土框架结构设置楼梯隔震防倒塌支座的效果,利用ETABS有限元软件建立计入楼梯、不计入楼梯、设置滑动支座和隔震防倒塌支座的4个框架结构模型,进行地震作用下梯段板下端不同构造措施对框架结构地震反应影响的对比分析。研究结果表明:与不考虑楼梯作用相比,设置隔震防倒塌支座后,钢筋混凝土框架结构的周期、振型、地震作用、层间位移、框架梁柱和楼梯梁柱的地震内力等均未明显变化,表明隔震防倒塌支座能有效地卸去梯段板的斜撑作用;与滑动支座结构相比,隔震防倒塌支座结构沿地震动输入方向的水平滑动位移基本相同,同时减小了梯段板竖向翘起位移。 相似文献
3.
支座硬化以及隔震层与周围挡土结构的碰撞导致增量动力分析曲线发生突变，针对这一问题提出了适用于同时考虑支座硬化和结构碰撞的地震需求模型。选取21条地震动记录，对隔震结构进行增量动力分析及易损性分析。通过一个21层框架-剪力墙结构的实际工程算例，应用所提出的模型，研究地震作用下隔震沟宽度对结构动力响应及易损性的影响。研究结果表明：碰撞后结构虽然隔震层位移减小，但会造成楼层峰值加速度明显放大及隔震效果的减弱。在发生硬化和碰撞时，滞回圈均会出现明显的上翘现象，IDA曲线会出现突变。在极罕遇地震作用下，当隔震沟宽度较大时，基础隔震结构上部结构出现损伤的超越概率比隔震沟宽度较小的结构均有所减小，其中出现严重损伤的概率减小了17.17%,出现破坏的超越概率减小了3.50%。 相似文献
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5.
从Chi-Chi地震动数据中选取20条近场长周期地震记录和20条远场长周期地震记录,再从汶川地震渭河地震动数据中选取20条远场长周期地震记录作为输入,研究各个地震动记录相对应的地震动强度参数及其之间的相关性,筛选出了适合于长周期地震动的地震动强度指标,采用Pearson相关系数对筛选出的地震动强度指标与隔震体系的隔震层位移响应之间的相关性进行分析。结果表明:①在近、远场长周期地震动作用下,中长周期隔震结构的隔震层位移响应与频谱特征参数的相关性比较好,在进行中长周期隔震结构的抗震性能研究时,PGD、Sdavg及DSI与隔震结构的相关性较好,地震动强度指标在集集近场建议选取PGD和Sdavg,集集远场建议选取DSI和D/V,渭河远场建议选取Sdavg和DSI;②在强相关范围内考虑相关性的高低,近场和远场的长周期地震动强度指标建议分别选取PGD和DSI。 相似文献
6.
本文提出了一种基于叠层橡胶支座的大高宽比高层建筑分段隔震结构形式,并对同一高层建筑结构分别采用基础隔震、层间隔震和分段隔震三种不同形式时进行了数值模拟对比分析。结果表明,采用分段隔震形式可明显减小高层建筑结构的顶层侧向位移、中间隔震层的相对位移和下支柱端应力,使结构的侧向位移集中于两个隔震层上,耗散了大部分地震输入能量,保障了与隔震层相连的构件的安全性,防止了由于支座受拉或剪压破坏导致上部结构倾覆倒塌现象的发生。 相似文献
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基于概率和位移的框支剪力墙结构抗震性能评估方法 总被引：1，自引：0，他引：1
本文严格按照中国规范设计出典型的带转换层部分框支剪力墙钢筋混凝土结构,通过弹塑性分析程序IDARC2D对该结构进行多个地震动作用下的大震弹塑性时程分析,得到结构及各个构件的反应量的统计特征,再参照美国基于性能抗震设计规范ASCE-41-06的结构与构件变形限值作为性能指标,计算出结构和各个构件的可靠度和可靠指标,作为评价结构抗震性能的标准,总结归纳出基于概率和位移的抗震设计方法的思路.最后运用该方法,对7、8度烈度区的框支剪力墙结构进行可靠性分析,通过对比分析,研究考虑内力增强措施、层间位移角控制条件、竖向构件轴压比限制条件、层刚比控制准则和竖向构件最小配筋率等因素对不同抗震烈度区的框支剪力墙结构的可靠性的影响,从而评价中国规范抗震措施和构造措施的有效性. 相似文献
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隔震结构"小震不坏"的动力可靠度分析 总被引：7，自引：2，他引：5
本文探讨叠层橡胶隔震体系在“小震不坏”条件下的动力可靠度分析。基于等效线性化的隔震工程设计参数,建立非比例阻尼隔震结构模型。采用双过滤白噪声功率谱模型描述地震动,并用林家浩虚拟激励法进行随机响应分析。以各层的最大层间位移响应作为控制指标,取结构的弹性位移限值作为位移极限值,建立功能状态方程。根据一次二阶矩方法,用串联模式计算体系的总体可靠度。文末选用了一个7层隔震框架作为数值算例,探讨了隔震阻尼、寒冷环境、节点构造误差所引起的隔震层刚度上升,以及场地土类别等对体系动力可靠性的影响。 相似文献
9.
近断层地震动中长周期、短持时和高能量的加速度脉冲将对高层摩擦摆基础隔震结构的减震性能产生不利影响，考虑土-结构相互作用（SSI效应）后的隔震结构将产生动力耦合效应，可能进一步放大隔震结构地震响应。为此，通过一幢框架-核心筒高层摩擦摆基础隔震结构的非线性地震响应分析，考察近断层脉冲型地震动作用下框架-核心筒摩擦摆基础隔震结构的层间位移角、楼层加速度和隔震层变形等响应规律，揭示隔震体系的损伤机理。基于集总参数SR （sway-rocking）模型，分析不同场地类别与不同地震动类型对隔震体系动力响应影响规律。结果表明:高层摩擦摆基础隔震结构在近断层脉冲型地震动作用下的减震效果相比普通地震动减震效果变差，楼层剪力、层间位移角和隔震层变形等超越普通地震动作用下的1.5倍；对于Ⅲ和Ⅳ类场地类别，考虑SSI效应使隔震结构的地震响应进一步放大，弹塑性层间位移角随着土质变软增大尤为明显。 相似文献
10.
近年来,越来越多的高层建筑采用了基础隔震技术,但研究表明,高层隔震建筑在超烈度地震作用下仍可能发生破坏或倒塌,因此开展高层建筑隔震前后的地震风险对比分析显得尤为重要,可直观显示该类建筑在将来可能发生地震作用下的表现。在进行隔震结构地震风险分析时,上部结构、隔震支座、地震动的不确定性对易损性分析结果有重要影响,因此本文以高层RC框架剪力墙结构为研究对象,在综合考虑隔震支座、上部结构和地震动参数随机性的基础上,定义上部结构层间位移角及隔震层位移2个参数为结构损伤的评价指标,对隔震前后结构的地震易损性进行了对比分析,进而开展地震风险评价。结果表明:隔震技术极大地减小了结构的地震脆弱性,提高了结构的抗震安全性,但其在超烈度大震作用下也具有倒塌的风险;相比于非隔震结构,隔震结构的风险损失值可降低6倍。 相似文献
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选取按照现行规范设计的既有建筑进行有限元建模,考虑地震动的不确定性对其进行大量增量动力分析(IDA),得到模型的IDA曲线簇。在此基础上对其进行地震需求概率分析和概率抗震能力分析,拟合得到结构的易损性曲线,据此对结构的倒塌概率进行定量评估,并比较基于非线性分析与性能评估软件PERFORM-3D的纤维模型和塑性铰模型的分析结果。结果表明:按照我国现行规范设计的钢筋混凝土(RC)框架结构,在预期的罕遇地震作用下倒塌概率较小,可满足"大震不倒"的要求;基于PERFORM-3D的截面纤维模型所得的RC框架结构,经非线性分析所得的倒塌概率相对保守,安全储备更高。 相似文献
12.
Fragility curves are found to be useful tools for predicting the extent of probable damage. They show the probability of highway structure damage as a function of strong motion parameters, and they allow the estimation of a level of damage probability for a known ground motion index. In this study, an analytical approach was adopted to develop the fragility curves for highway bridges based on numerical simulation. Four typical RC bridge piers and two RC bridge structures were considered, of which one was a non‐isolated system and the other was an isolated system, and they were designed according to the seismic design code in Japan. From a total of 250 strong motion records, selected from Japan, the United States, and Taiwan, non‐linear time history analyses were performed, and the damage indices for the bridge structures were obtained. Using the damage indices and ground motion parameters, fragility curves for the four bridge piers and the two bridge structures were constructed assuming a lognormal distribution. It was found that there was a significant effect on the fragility curves due to the variation of structural parameters. The relationship between the fragility curve parameters and the over‐strength ratio of the structures was also obtained by performing a linear regression analysis. It was observed that the fragility curve parameters showed a strong correlation with the over‐strength ratio of the structures. Based on the observed correlation between the fragility curve parameters and the over‐strength ratio of the structures, a simplified method was developed to construct the fragility curves for highway bridges using 30 non‐isolated bridge models. The simplified method may be a very useful tool to construct the fragility curves for non‐isolated highway bridges in Japan, which fall within the same group and have similar characteristics. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Fragility curves express the probability of structural damage due to earthquakes as a function of ground motion indices, e.g., PGA, PGV. Based on the actual damage data of highway bridges from the 1995 Hyogoken‐Nanbu (Kobe) earthquake, a set of empirical fragility curves was constructed. However, the type of structure, structural performance (static and dynamic) and variation of input ground motion were not considered to construct the empirical fragility curves. In this study, an analytical approach was adopted to construct fragility curves for highway bridge piers of specific bridges. A typical bridge structure was considered and its piers were designed according to the seismic design codes in Japan. Using the strong motion records from Japan and the United States, non‐linear dynamic response analyses were performed, and the damage indices for the bridge piers were obtained. Using the damage indices and ground motion indices, fragility curves for the bridge piers were constructed assuming a lognormal distribution. The analytical fragility curves were compared with the empirical ones. The proposed approach may be used in constructing the fragility curves for highway bridge structures. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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A method for the development of earthquake intensity–damage relations, given as fragility curves and damage probability matrices is proposed in this paper. The proposed method is applied on reinforced-concrete frame-wall structures. Two sets of fragility curves and damage probability matrices are developed. The first one is for reinforced-concrete frame structures lower than 10 stories. For this purpose, a six-story frame structure is used. The other set is defined for reinforced-concrete frame-wall structures higher than 10 stories. A 16-story frame-wall structure was chosen as a sample. The sample structures were designed according to Macedonian design code. The conditions of the local seismic hazard were the subject of special concern for the development of earthquake intensity–damage relations. Because of the limited number of real time histories from the Skopje region, a set of 240 synthetic time histories were generated. Geological dates from the Skopje region were used. Response of the sample structures under earthquake excitation was defined performing nonlinear dynamic analysis. Modeling of the nonlinear behavior of the structural elements was completed according to state-of-the-art methods in this field. A modified Park and Ang damage model was chosen as a measure of the structure's response to earthquake excitation. Five damage states were defined to express the condition of damage. As a result of the analytical research, the values of the global damage index corresponding to each damage state were determined. Using the dates from the nonlinear dynamic analysis of the sample structures under all 240 synthetic time histories, the two sets of fragility curves and damage probability matrices were defined. 相似文献
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通过对隔震结构进行非线性动力响应分析,分别研究地震动参数和支座参数对结构地震响应的影响。首先,建立铅芯橡胶支座基础隔震结构的非线性运动方程;然后,以人工合成脉冲型地震动作为输入,运用MATLAB进行编程并求解结构在脉冲型地震动作用下的地震响应;最后,分别研究速度脉冲周期、支座屈服力、屈服后与屈服前的刚度比对隔震支座最大位移和上部结构层间位移的影响。研究结果表明,脉冲周期对结构地震响应影响很大,在进行隔震设计时应使结构自振周期远离脉冲周期;支座刚度比对结构地震响应影响较大,在进行支座选型时应重点关注;支座屈服力对支座位移的影响显著,屈服力越大,支座位移越小。 相似文献
16.
隔震结构具有较长自振周期,且容易受地震动长周期特性的影响,因此其在长周期地震动作用下的抗震性能值得研究。以某基于规范设计的基础隔震结构为例,通过对该结构在规范规定地震作用和远场长周期地震作用下的地震响应进行分析和对比,研究长周期地震动对结构地震响应的影响;通过对钢筋和混凝土的损伤状态进行定义和标识,探讨长周期地震作用下基础隔震结构的损伤分布规律。研究结果表明,长周期地震动作用下隔震结构发生破坏的概率远大于具有相同峰值地面加速度的普通地震动,其中长周期地震动反应谱的谱峰值"后移"被认为是造成这种情况的主要原因,且长周期地震动作用下隔震结构的损伤分布并不均匀,其主要集中在结构的底层。 相似文献
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近断层脉冲型地震动作用下隔震结构地震反应分析 总被引：17，自引：5，他引：17
隔震结构在远震场地减震效果良好，但是近断层地震动的明显的长周期速度和位移脉冲运动可能对隔震建筑等长周期结构的抗震性能和设计带来不利影响，需要深入探讨。本文首先讨论近断层地震动的长周期脉冲运动特征，然后以台湾集集地震8条典型近震记录和其它4条常用近震记录以及4条远震记录作为地震动输入，对两幢安装铅芯橡胶隔震支座的钢筋混凝土框架隔震结构进行非线性地震反应时程分析，通过比较探讨了算例计算结果，定量说明隔震结构的近震脉冲效应显著，是隔震设计不容忽视的问题。 相似文献
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以某典型的20层钢筋混凝土框架剪力墙结构作为研究对象，研究基于性能的RC框架剪力墙结构易损性分析方法。首先选择合适的地震动记录，以0.2g为步长进行调幅后，建立300个结构-地震动样本空间，并确定结构损伤指标和性能参数；然后应用增量动力分析方法计算结构的地震动力响应，选择基本周期加速度反应谱为地震动参数，以研究结构反应的不确定性，并深入分析地震动参数与结构地震需求参数的关系；在此基础上，建立该结构基于加速度反应谱的易损性曲线进行结构易损性分析与评估。结果表明：随着地震动强度的增大，IDA曲线由单调增加变为非单调增加，分位曲线（16%，50%和84%）可以准确地衡量结构的性能；框剪结构在地震作用下的抗震性能表现良好，随着地震强度的增长，各性能超越概率大小的增长速度是不同的。 相似文献
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Modelling uncertainty can significantly affect the structural seismic reliability assessment. However, the limit state excursion due to this type of uncertainty may not be described by a Poisson process as it lacks renewal properties with the occurrence of each earthquake event. Furthermore, considering uncertainties related to ground motion representation by employing recorded ground motions together with modelling uncertainties is not a trivial task. Robust fragility assessment, proposed previously by the authors, employs the structural response to recorded ground motion as data in order to update prescribed seismic fragility models. Robust fragility can be extremely efficient for considering also the structural modelling uncertainties by creating a dataset of one-to-one assignments of structural model realizations and as-recorded ground motions. This can reduce the computational effort by more than 1 order of magnitude. However, it should be kept in mind that the fragility concept itself is based on the underlying assumption of Poisson-type renewal. Using the concept of updated robust reliability, considering both the uncertainty in ground motion representation based on as-recorded ground motion and non ergodic modelling uncertainties, the error introduced through structural reliability assessment by using the robust fragility is quantified. It is shown through specific application to an existing RC frame that this error is quite small when the product of the time interval and the standard deviation of failure rate is small and is on the conservative side. 相似文献