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为研究隔震技术对超大型冷却塔抗震性能的影响，以某混凝土冷却塔为研究对象，利用SAP2000分别建立基础隔震与层间隔震的冷却塔有限元模型，开展了结构动力特性分析和非线性时程分析，与非隔震冷却塔相比，对比分析了基础隔震与层间隔震的隔震效果。研究结果表明：基础隔震技术与层间隔震技术均能有效地延长冷却塔结构的自振周期，降低结构地震反应，第一阶自振周期延长至近3倍，整体平动模态提前至前两阶，扭转模态提前至第三阶。对比基底剪力，基础隔震的减震性能略优于层间隔震；对比相对位移，喉部以上，基础隔震与层间隔震的冷却塔减震效果基本相同，喉部以下，层间隔震的减震效果优于基础隔震；对比加速度放大系数，塔筒各位置处基础隔震的减震效果均优于层间隔震，支柱位置处，与非隔震冷却塔相比，基础隔震的加速度略有放大。研究结果可为冷却塔的减隔震分析提供参考。 相似文献
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层间隔震结构工作机理研究 总被引：15，自引：2，他引：15
本文建立了层间隔震结构动力分析模型,对层间隔震结构地震反应的主要影响系数进行了分析。结果表明:在一定的频率比范围内,当隔震层的位置较高时,隔震结构下部位移和上部加速度均显著减小,表现出与TMD相似的工作机理;当隔震层的位置较低时,隔震结构下部位移和上部加速度均变化不明显,其工作机理与基础隔震相似。隔震层的阻尼比对层间隔震结构的减震效果也有较大影响,阻尼比越大,减震效果越好。 相似文献
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层间隔震结构作为一种新型的隔震形式,不仅可以降低上部结构的动力响应,还可以弥补基础隔震结构的不足.现有研究多集中在远场地震作用下的规则层间隔震结构.本文利用通用结构分析与设计软件SAP2000分别模拟了一幢8层带裙房钢筋混凝土框架层间隔震结构、基础隔震结构和抗震结构,分析并对比了三种结构在近场地震作用下动力响应特征.结果表明在近场条件下三种结构顶层均出现不同程度的鞭梢效应;相比抗震结构两种隔震结构具有很好的减震效果,而且基础隔震结构的减震效果好于层间隔震结构;由于结构刚度突变的部位剪力较大,所以应对其裙楼顶部予以加强. 相似文献
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作为当前高速铁路建造中出现的一种新型客站形式———房桥合一结构体系已经开始应用于实际工程,其抗震设防研究有着迫切需求和重要意义。基于此,本文对房桥合一结构中设置层间隔震来实现减震控制开展研究工作,并重点探讨此类控制方法的参数优化策略。首先建立了房桥合一结构数值模型,通过引入虚拟激励法推导了高效准确的随机计算式,继而指出采用参数域方法进行优化更为合理,它可实现隔震层参数有效配置。最后,通过数值研究对随机地震激励下房桥合一结构层间隔震优化策略进行了验证分析,分别基于单桥模型和多桥模型研究了其减震机理和减震效果,提出可提高减震效果的参数优化策略。本文研究结果表明:设置经过参数合理优化的层间隔震装置对房桥合一结构减震是可行且有效的。 相似文献
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加层减震结构振动台试验分析 总被引：5，自引：0，他引：5
本文针对一加层减震模型结构对隔震层上下部频率比进行优化设计,对隔震层采用侧移刚度偏小值、优化值和偏大值的加层减震模型结构进行地震模拟振动台试验。试验结果表明,经过参数优化设计的加层减震模型结构有明显减震效果,在试验中使设防水准提高了一级,由直接加层的局部破坏到加层减震后的大震不坏;对于一般的加层减震结构,采用以最大限度地降低既有结构的层间位移为优化目标是合理的,具有普遍的工程意义。 相似文献
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利用实体软钢棒作为消能限位装置，将一种摩擦性能优良的二硫化钼材料作为隔震支座的滑移材料，提出并制作了一种可以应用于框架结构既能隔震又可以消能的新型摩擦滑移隔震装置。探讨了其设计方法和应用方法，并对安装了该新型摩擦滑移隔震装置的一相似比为1:5的5层框架结构模型进行了振动台试验，测试了框架结构在单向地震波作用下的地震反应规律，分析了摩擦滑移隔震结构的加速度反应、层间剪力反应、隔震层滑移量及隔震层剪力的变化规律。结果表明:一般情况下当设防烈度为8度，Ⅱ类场地时，该隔震结构的加速度响应可降低50%左右，层间剪力响应可降低50%左右，减震效果比较明显。另外，只要确定合理的构造方案和实施方案，这种新型摩擦滑移隔震装置就能满足框架结构的隔震减震要求，可应用于实际工程结构中。 相似文献
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高层隔震结构非线性地震响应分析及设计方法研究 总被引：3，自引：0，他引：3
高层隔震结构的分析理论和设计方法是目前隔震技术向高层建筑推广的2个关键理论问题。本文以高烈度区宿迁市已经竣工的高层隔震建筑阳光大厦为工程实例,对高层隔震结构的非线性地震响应分析方法进行了研究,包括隔震支座竖向不同拉压刚度的模拟、各种类型的隔震支座水平力学特性的准确模拟,以及不同地震动输入方式和输入角度对隔震支座受拉情况的影响分析等;在此基础上,对隔震层的设计方法进行了分析,提出了隔震层设计的基本原则,进而给出了控制隔震层设计的基本指标,包括隔震支座的长期面压、极值面压、隔震层偏心率等;最后,对高层隔震结构的相关构造要求进行了必要的说明。 相似文献
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实际地震具有多维特性，只考虑水平向作用往往不够真实全面，而且远场长周期地震动不同于普通地震动，具有周期长、持时长、低频成份丰富等特征，对周期较大的隔震类结构会产生不利影响，在考虑SSI效应(soil-structure interaction, SSI)中尤为复杂，需深入探讨。基于此，建立大底盘层间隔震结构，在三维地震动激励下，探讨普通地震与远场长周期地震对层间隔震结构的不同影响，并分析考虑SSI效应对结构的不同程度影响。结果表明：三维地震下，远场长周期对层间隔震结构产生的地震响应远大于普通地震；考虑SSI效应时，随着土体变软，结构响应增大；针对传统水平隔震支座，在三维远场长周期地震下出现层间位移角和支座位移超限问题，设置三维隔震支座，解决了超限问题，分析结果表明其隔减震效果明显优于传统水平隔震支座。 相似文献
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The mid‐story isolation design method is recently gaining popularity for the seismic protective design of buildings located in the areas of high population. In a mid‐story isolated building, the isolation system is incorporated into the mid‐story rather than the base of the building. In this paper, the dynamic characteristics and seismic responses of mid‐story isolated buildings are investigated using a simplified three‐lumped‐mass structural model for which equivalent linear properties are formulated. From the parametric study, it is found that the nominal frequencies of the superstructure and the substructure, respectively, above and below the isolation system have significant influences on the isolation frequency and equivalent damping ratio of a mid‐story isolated building. Moreover, the mass and stiffness of the substructure are of greater significance than the superstructure in affecting the dynamic characteristics of the isolated building. Besides, based on the response spectrum analysis, it is noted that the higher mode responses may contribute significantly to the story shear force of the substructure. Consequently, the equivalent lateral force procedure of design codes should carefully include the effects of higher modes. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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耗能-隔震柔性底层钢管混凝土-钢筋混凝土组合框架的实验研究 总被引：1，自引：1，他引：1
本文用钢管混凝土柱作为结构底层耗能柱、用承重墙和隔震器控制结构底层倒塌破坏,从而提出了一种新的耗能-隔震柔性底层结构体系。通过本文12根钢管混凝土柱和文献[7]中7根钢管混凝土柱的低周疲劳实验,初步确定了钢管混凝土柱地震损伤模型的参数;通过两个钢管混凝土-钢筋混凝土三层框架模型和一个纯钢筋混凝土三层框架模型的拟动力实验,研究和比较了两类结构体系的地震损伤。 相似文献
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砂垫层具有取材方便、造价低、施工简便的特点,为了更好地在农居工程建设中推广应用地基砂垫层隔震技术,通过制作农村房屋结构模型,进行地基砂垫层隔震体系与无隔震体系的大型振动台试验,研究了地基砂垫层隔震体系的隔震性能。基于结构加速度反应、结构位移反应和结构应变反应三个方面,对比分析无隔震试验和地基砂垫层隔震试验的结果,研究地基砂垫层隔震体系的隔震性能。结果表明:地基砂垫层隔震体系能够有效地减小上部结构的地震加速度反应、层间位移反应和应变反应,具有良好的隔震效果;输入地震动的量级是影响地基砂垫层隔震体系隔震效果的一个重要因素。 相似文献
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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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A new isolation interface is proposed in this study to retrofit existing buildings with inadequate soft stories as well as new structures to be constructed with soft first story intended for architectural or functional purposes. The seismic interface is an assembly of bearings set in parallel on the top of the first story columns: the multiple‐slider bearings and rubber bearings. The multiple‐slider bearing is a simple sliding device consisting of one horizontal and two inclined plane sliding surfaces based on polytetrafluoroethylene and highly polished stainless steel interface at both ends set in series. A numerical example of a five‐story reinforced concrete shear frame with soft first story is considered and analyzed to demonstrate the efficiency of the proposed isolation system in reducing the ductility demand and damage in the structure while maintaining the superstructure above the bearings to behave nearly in the elastic range with controlled bearing displacement. Comparative study with the conventional system as well as various isolation systems such as rubber bearing interface and resilient sliding isolation is carried out. Moreover, an optimum design procedure for the multiple‐slider bearing is proposed through the trade‐off between the maximum bearing displacement and the first story ductility demand ratio. The results of extensive numerical analysis verify the effectiveness of the multiple‐slider bearing in minimizing the damage from earthquake and protecting the soft first story from excessively large ductility demand. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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A new base‐isolation mechanism corresponding to a variance of the stepping A‐shaped frame is proposed and its seismic performance is investigated numerically for strong ground accelerations with peak values in the range from 0.5 to 1g. In its simplest two‐dimensional form, the system consists of a frame with two telescoping legs pinned at the apex at a sharp angle. The legs are attached to the foundation through a spring and a damper acting in parallel. Both the springs and viscous dampers have bilinear characteristics that make them very stiff in compression but very soft in tension. As the structure rocks sideways, the length of the loaded leg remains essentially constant while the length of the unloaded leg increases. When the ground acceleration changes direction, the process is reversed. The resulting system has three main characteristics: (i) as the structure steps on a rigid leg, the maximum acceleration that can be transmitted to the superstructure is limited to a value which is approximately independent of the amplitude of the ground motion; (ii) there is a systematic lifting of the superstructure with kinetic energy being systematically transformed into potential energy during the strong phase of the ground motion; and (iii) the system is slowly self‐centering at the end of the earthquake. The seismic performance of the system is evaluated for a tall bridge pier and for a smaller frame that could be used in a multi‐story building. The results obtained for the 1940 El Centro ground motion scaled to 1g and for the near‐field Rinaldi ground motion recorded during the Northridge earthquake show that substantial reductions of the absolute acceleration can be obtained with reasonable relative displacements of the superstructure and small strokes in the isolation devices. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Viscous and other damping devices are often used as elements of seismic isolation systems. Despite the widespread application of nonlinear viscous systems particularly in Japan (with fewer applications in the USA and Taiwan), the application of viscous damping devices in isolation systems in the USA progressed intentionally toward the use of supplementary linear viscous devices due to the advantages offered by these devices. This paper presents experimental results on the behavior of seismically isolated structures with low damping elastomeric (LDE) and single friction pendulum (SFP) bearings with and without linear and nonlinear viscous dampers. The isolation systems are tested within a six‐story structure configured as moment frame and then again as braced frame. Emphasis is placed both on the acquisition of data related to the structural system (drifts, story shear forces, and isolator displacements) and on non‐structural systems (floor accelerations, floor spectral accelerations, and floor velocities). Moreover, the accuracy of analytical prediction of response is investigated based on the results of a total of 227 experiments, using 14 historic ground motions of far‐fault and near‐fault characteristics, on flexible moment frame and stiff braced frame structures isolated with LDE or SFP bearings and linear or nonlinear viscous dampers. It is concluded that when damping is needed to reduce displacement demands in the isolation system, linear viscous damping results in the least detrimental effect on the isolated structure. Moreover, the study concludes that the analytical prediction of peak floor accelerations and floor response spectra may contain errors that need to be considered when designing secondary systems. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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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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This paper evaluates the ability of simplified superstructure models, including two shear frame models and a single-story model, in predicting global responses of a full-scale five-story steel moment-frame buildings isolated by triple friction pendulum bearings subjected to earthquake motions. The investigated responses include displacement of the isolation system, roof drift, story drift, and floor acceleration. Mechanical properties of the simplified superstructure models were derived from the modal information of a verified full 3-D model. The comparison between the analytical responses and experimental responses shows that the simplified models can well predict the displacement of the isolation system. Furthermore, the shear-frame models are adequate for predicting floor acceleration when the specimen is subjected to horizontal ground motions. However, when the specimen is subjected to 3-D motions, the shear-frame models un-conservatively predict floor acceleration. The full 3-D model improves the prediction of story drift compared with the simplified models for both horizontal and 3-D motions. 相似文献