拟负刚度磁流变智能隔震系统振动台试验研究

为研究拟负刚度控制算法及磁流变智能隔震系统的有效性和适应性,将自主研发的最大出力为10kN的磁流变液阻尼器(MRFD)安装在隔震层中心,并选取4条有代表性的远近场地震波,峰值加速度由0.1g~0.9g逐步增大,分别对普通隔震结构、输入电流为0A和1A的被动控制结构以及采用基于位移的拟负刚度(DPNS)控制算法的智能控制结构进行振动台试验。通过对结构响应和阻尼器响应的对比分析,研究拟负刚度控制算法的减震效果和磁流变智能控制系统的耗能特性。结果表明：恒定电流为0A的被动控制可同时降低上部结构反应和隔震层位移,但是减震效果有限;恒定电流为1A的被动控制对隔震层位移降低效果明显,但是在多遇地震及远场地震作用下放大了上部结构反应;DPNS控制可同时降低隔震层位移和多遇、设防地震甚至罕遇地震作用下上部结构的反应,且适应于不同的地震动特性;试验中控制系统存在的时滞效应使得DPNS控制力在多遇、设防地震作用下具有较小值,同时罕遇地震作用下具有较强的耗能能力。     

Improvement of near-fault seismic isolation using a resettable variable stiffness damper

A seismic structure isolated by a conventional passive isolation system is usually a long-period structural system; therefore, although its dynamic response may be effectively mitigated in a regular earthquake, the responses may be considerably amplified in a near-fault earthquake with long-period characteristics, due to the low-frequency resonant effect. In order to overcome this problem, a sliding isolation system equipped with a new type of the semi-active damper called a resettable variable stiffness damper (RVSD) is proposed in this study. An RVSD damper is similar to a conventional resettable stiffness damper, except that it has a variable stiffness part. By controlling the variable stiffness, the damper force provided by the RVSD will follow a target force that is determined on-line by a general, active control law. As a result, the RVSD damper is able to prevent the abrupt changes of the damper force that inevitably exists in a conventional resettable damper. The harmonic and seismic responses of an isolation system with the RVSD are studied numerically and compared with the other types of isolation systems. The simulated results demonstrate that the RVSD is able to attenuate the low-frequency resonance behavior of the seismic isolation system induced by long-period ground motions. As compared with an isolation system with a conventional resettable damper, the study shows that isolation with the RVSD is superior in reducing the acceleration response due to a near-fault earthquake, while maintaining its effectiveness in the suppression of the isolator displacement.     

农村房屋地基砂垫层隔震系统振动台试验研究

为研究农村房屋的防震减灾措施,验证地基砂垫层的减震效果,制作了1/4缩尺的1层砌体结构模型,采用大型振动台进行了有地基砂垫层隔震措施与无隔震措施的对比试验。采用自行研制的大型叠层剪切模型土箱,地基土采用粉质黏土,砂垫层采用中粗河砂。进行多工况单向水平激励的模拟地震试验。结果表明:在峰值加速度为0. 1g和0. 2g的El Centro波激励下,地基砂垫层隔震系统主要依靠砂垫层的塑性变形消耗部分地震能量,从而减少了上部结构的地震反应;在峰值加速度为0. 4g的El Centro波激励下,一方面依靠砂土的塑性变形消耗部分地震能量,另一方面由于结构基础与地基土之间的相对滑移运动,限制了地震反应向上部结构的传递;在基础埋深范围内回填砂土的措施既促进了结构基础与地基土之间的相对滑移,又对上部结构的位移反应起到了较好的限制作用;地基砂垫层隔震系统可有效减小结构的加速度、层间位移、层间剪力,在峰值加速度为0. 4g的El Centro波激励下,楼层加速度峰值减小35%,层间位移峰值减小59%,层间最大剪力减小34%。     

Aseismic smart building isolation systems under multi-level earthquake excitations: Part I,conceptual design and nonlinear analysis

As a novel structural control strategy, tuned mass damper (TMD) inspired passive and semi-active smart building isolation systems are suggested to reduce structural response and thus mitigate structural damage due to earthquake excitations. The isolated structure’s upper stories can be utilized as a large scaled TMD, and the isolation layer, as a core design point, between the separated upper and lower stories entails the insertion of rubber bearings and (i) viscous dampers (passive) or (ii) resettable devices (semi-active). The seismic performance of the suggested isolation systems are investigated for 12-story reinforced concrete moment resisting frames modeled as “10+ 2” stories and “8+ 4” stories. Passive viscous damper or semi-active resettable devices are parametrically evaluated through the optimal design principle of a large mass ratio TMD. Statistical performance metrics are presented for 30 earthquake records from the three suites of the SAC project. Based on nonlinear structural models, including P-delta effects and modified Takeda hysteresis, the inelastic time history analyses are conducted to compute the seismic performances across a wide range of seismic hazard intensities. Results show that semi-active smart building isolation systems can effectively manage seismic response for multi-degree-of freedom (MDOF) systems across a broader range of ground motions in comparison to uncontrolled case and passive solution.     

Smart outrigger damper system for response reduction of tall buildings subjected to wind and seismic excitations

The outrigger damper system has recently been proposed to reduce the dynamic response of tall buildings subjected to lateral loads. Previous studies have shown that the outrigger damper system could effectively increase the response reduction capacity of tall buildings. The outrigger damper system was used not only for a response reduction of tall buildings, but also for adjusting the differential column shortening. When an outrigger damper system is designed optimally for wind or earthquake loads, it shows good control performance against each target excitation. On the other hand, the outrigger damper system designed for the wind load cannot effectively control the seismic responses and vice versa. This study examined the control performance of a smart outrigger damper system for reducing both the wind and seismic responses. The smart outrigger damper system was comprised of magnetorheological dampers. A fuzzy logic control algorithm, which was optimized by a multi-objective genetic algorithm, was used to control the smart outrigger damper system. Numerical analysis showed that the smart outrigger damper system could provide superior control performance for the reduction of both wind and earthquake responses compared to the general outrigger system and passive outrigger damper system.     

Effect of two horizontal components of earthquake on nonlinear response of torsionally coupled base isolated structures

Torsion in base‐isolated structures using bilinear rubber isolators effected by two horizontal components of earthquake simultaneously is investigated under various principal parameters including number of storeys; ratio of uncoupled torsional frequency to lateral frequency in the superstructure; ratio of uncoupled torsional frequency to lateral frequency in the isolation system; mass eccentricity in the superstructure and isolation system; and, in addition, the direction of eccentricity. Structure was supposed a shear structure and it was modeled by using concentrated mass and springs. Isolators are modelled by using nonlinear springs considering the interaction of isolator behaviour in two directions. The effect of variation in considered parameters on the behaviour of the superstructure and isolation system is investigated under seven ground motions. It is demonstrated that the parameters affect asymmetric structure behaviour with respect to symmetric one. The results of our investigations help us to understand the asymmetric structure behaviour under bidirectional earthquake by comparing it with a symmetric one. These results demonstrate that asymmetry in the superstructure or isolation system could have a significant effect on the torsional behaviour of isolated structures. In addition, the results show that the use of rigid superstructures and calculation of dynamic torsion by multiplying eccentricity by the dynamic base shear are unacceptable assumptions. Torsional effect on the isolated structural behaviour is amplified by considering two horizontal components of earthquake and comparing them with just one horizontal component. Copyright © 2010 John Wiley & Sons, Ltd.     

极罕遇地震作用下铅芯橡胶隔震支座基础隔震结构抗震性能研究

基础隔震结构在设计地震和罕遇地震作用下具有良好的抗震性能。随着GB 18036—2015《中国地震动参数区划图》引入了极罕遇地震作用，有必要探讨基础隔震结构在极罕遇地震作用下的抗震性能。以两自由度体系(简化模型)和多自由度体系(纤维模型)的铅芯橡胶隔震支座(LRB)基础隔震结构为研究对象，基于弹塑性时程分析的统计结果，分析并比较了设计、罕遇和极罕遇地震作用下上部结构屈服承载力(即降低上部结构抗震设防烈度)和LRB隔震支座力学性能参数对整个LRB基础隔震结构抗震性能的影响。分析结果表明：极罕遇地震作用下，采用降低抗震设防烈度的方式对隔震后的上部结构进行结构设计并不可取；为了保证在极罕遇地震作用下LRB基础隔震结构的上部结构和LRB隔震支座不发生破坏，应尽可能使用大直径和低橡胶剪切模量的LRB隔震支座；如何保证LRB基础隔震结构在设计地震和罕遇地震作用下的性能要求以及在极罕遇地震作用下的安全性能是一个具有挑战性的问题。     

组合基础隔震房屋模型振动台试验研究

基础隔震能有效地降低上部结构的地震作用,但不同的隔震体系,隔震效果不同.本文根据叠层橡胶支座和滑板摩擦隔震支座的特点,提出组合基础隔震系统,以中国和日本国的在建隔震房屋为工程背景,进行了组合基础隔震房屋模型和基础固定房屋型模拟地震动振动台试验,并对两种试验结果进行了能量分析,分析结果表明组合基础隔震系统中叠层橡胶支座能自动复位,滑板摩擦隔震支座具有良好的耗能能力,隔震效果明显,组合基础隔震系统是一种简单、经济、有效具有广泛应用价值的基础隔震形式.本文获得的大量振动台试验结果可以为隔震设计和加固中使用这种隔震系统及进一步的理论分析提供重要依据.     

宿迁市府苑小区综合楼隔震分析

宿迁市府苑小区综合楼位于 8度区 ,设计基本地震加速度值为 0 3 0 g ,为 6层底部框架砌体结构 ,平面呈三折线形。工程采用基础隔震技术进行结构设计 ,隔震层由橡胶隔震支座、滑移支座、粘滞消能器组成。对隔震体系空间模型的时程分析表明 :采用基础隔震措施可显著降低上部结构的地震作用 ;设置粘滞消能器能较好地解决降低上部结构的地震作用和限制隔震层位移之间的矛盾 ,有效地消除结构的扭转效应     

Finite element formulations and theoretical study for variable curvature friction pendulum system

The friction pendulum system (FPS), a type of base isolation technology, has been recognized as a very efficient tool for controlling the seismic response of a structure during an earthquake. However, previous studies have focused mainly on the seismic behavior of base-isolated structures far from active earthquake faults. In recent years, there have been significant studies on the efficiency of the base isolator when subjected to near-fault ground motions. It is suggested from these studies that the long-duration pulse of near-fault ground motions results in significant response of a base-isolated structure. In view of this, an advanced base isolator called the variable curvature friction pendulum system (VCFPS) is proposed in this study. The radius of the curvature of VCFPS is lengthened with an increase of the isolator displacement. Therefore, the fundamental period of the base-isolated structure can be shifted further away from the predominant period of near-fault ground motions. Finite element formulations for VCFPS have also been proposed in this study. The numerical results show that the base shear force and story drift of the superstructure during near-fault ground motion can be controlled within a desirable range with the installation of VCFPS. Therefore, the VCFPS can be adopted for upgrading the seismic resistance of the structures adjacent to an active fault.     

地震作用下合肥电视塔粘滞流体阻尼器减震的优化参数分析

本文以合肥电视塔为工程背景,探讨了粘滞流体阻尼器对高耸电视塔在强震作用下地震响应的振动控制。分别进行了电视塔在EL-Centro波、Taft波和人工合成的合肥波作用下,线性粘滞流体阻尼器对合肥电视塔地震响应的控制分析,并对阻尼器的参数进行了优化设计。分析表明,采用最优参数的粘滞流体阻尼器可以明显减小电视塔的地震响应。     

建筑结构地震反应的MR智能基础隔震控制

针对基础隔震局限于减小地震波高频成分对结构影响的缺点,将磁流变(MR)阻尼器与滚动隔震支座相结合形成MR智能基础隔震系统并应用到结构控制中.基于MR阻尼器的Sigmoid模型,进行模糊半主动控制策略设计.在不同种类不同强度的地震波作用下,对智能基础隔震控制下2层钢框架结构的反应进行了仿真分析.结果表明,MR智能基础隔震...     

基于弹塑性限位装置的基础隔震建筑地震碰撞行为

在近场速度脉冲型地震作用下,基础隔震建筑可能产生过大的支座变形,为了防止结构和隔震沟边缘产生刚性碰撞并对上部结构造成损伤,建议在隔震层高度用弹塑性限位装置来防止结构产生过大位移并实现一定程度的消能减震。提出了一组动力学方程,将建筑结构模型和Bouc-Wen单元串联,可以考虑隔震间隙的非线性动力响应。考虑了速度脉冲周期对结构响应的放大作用,根据弹塑性动力碰撞分析方程,以3组不同高度的钢框架结构基准模型为算例,计算了限位装置的弹性刚度和屈服力等因素对不同结构的弹塑性响应。结果表明：恰当选取用于碰撞限位的弹塑性限位装置的碰撞刚度与屈服力,既能有效限制隔震层的水平位移,上部结构也不会产生过大的反向动力响应,能够充分保护结构;在较易激发类共振效应的速度脉冲型地震动作用下,上部结构最大响应同弹塑性限位装置的弹性刚度与屈服力呈正相关性。     

摩擦摆隔震框架结构振动台试验研究

摩擦摆是一种常见的隔震装置,将基础和上部结构隔开,在地震发生时起到保护上部结构的作用。为研究摩擦摆隔震结构在地震作用下的响应,设计一个4层框架抗震结构与一个隔震结构以及它们对应的缩尺模型,选择了2条天然地震动和1条人工地震动,分别对2个缩尺模型进行振动台试验。试验考察2个结构的动力特性、层位移响应、楼层加速度以及隔震层的响应。研究表明：摩擦摆具有良好的隔震能力,能显著降低层位移以及楼层加速度,降低的幅度超过50%。     

设置非线性粘滞阻尼器结构地震响应的时程分析

本文基于国内外现有的粘滞阻尼器性能试验和计算研究,提出单自由度非线性粘滞阻尼器的计算方法。文中给出了粘滞阻尼器非线性运动方程的解法,并运用该方法进行了大量的比较计算,研究了单自由度非线性粘滞阻尼器的动力响应特性。     

宿迁市交通大厦采用粘弹性阻尼器的减震设计与研究

本文简要介绍了要求9度抗震设防的宿迁市13层交通大厦采用国产兰陵牌粘弹性阻尼器的减震结构设计 ,给出了它的弹塑性地震反应计算方法和主要计算结果。计算表明 ,设置粘弹性阻尼器后 ,上部结构可按8度抗震设防要求设计 ,在多遇、罕遇水平地震作用下 ,能分别满足承载力与变形的要求 ,节约主体结构造价约10%。     

含形状记忆合金自复位阻尼器隔震结构的地震反应分析

为了使隔震结构体系能够同时获得良好的隔震特性及震后自复位能力,本文利用形状记忆合金(SMA)材料在相变伪弹性阶段具有较好阻尼性能这一特点,采用SMA自复位阻尼器与常规叠层橡胶垫组合成自复位隔震装置。根据SMA材料相变伪弹性的本构模型,对SMA自复位阻尼器在反复循环荷载下的力学行为进行了数值模拟,得到了相应的滞回耗能曲线。提出了一种针对SMA自复位阻尼器的分段线性化恢复力模型,并依据剪切型层模型理论,编制了设有SMA自复位阻尼器隔震结构在地震作用下的弹塑性时程分析程序,对设有这种新型隔震装置工程结构进行地震反应分析。分析结果表明,这种隔震装置不仅可以大大减轻地震对上部结构的影响,而且还具有很好的震后复位能力,因此具有较好的工程应用前景。     

MR智能材料在结构振动控制中的应用

磁流变智能材料是一种可控流体,它能在强磁场作用下从牛顿流体变化为有较高屈服应力的粘中塑流体,这种变化为连续可逆与迅速,用其制成的阻尼器具有简单、体积小、能耗低、可连续调节等优点,是结构实施半主动控制的理想装置。本文简要介绍了磁流变智能材料磁流变效应的机现及影响因素,与电流变（ＥＲ）液作了简单比较,建立了ＭＲ可调阻尼器工作原理和力学模型,并介绍其用于工程结构风振与地震的半主动控制的实施原则及可用范围     

Study on dynamic response of large and small aspect ratio isolated buildings

An experimental study of a large aspect structure, 1:4 scale five‐storey steel frame, is presented. Seismic responses of the test model to the unilateral and bilateral excitations are compared. The effects of aspect ratio on the maximum acceleration, the storey drift of the superstructure, the maximum displacement and the vertical load of the isolation system are investigated. A comparison of the large aspect ratio isolated building with the small aspect ratio isolated building showed significant difference of the effects of aspect ratio subjected to disparate earthquake ground motions. Experimental results reveal that the aspect ratio is an important factor influencing the axial load action on isolators and the tension stress of the lead‐rubber bearings. The superstructure flexibility of the large aspect ratio building‐isolation system and the effects of the axial force variation of the lead‐rubber bearings should be carefully considered for design. Copyright © 2013 John Wiley & Sons, Ltd.     

近断层地震动作用下基础隔震结构的一体化动力优化设计

首先讨论了近断层地震动的脉冲运动特征和特性参数,并以台湾集集地震实际脉冲型近震记录作为地震动输入,以上部结构最大层间位移和构件体积最小化为目标,应用含潜在约束策略的序列二次规划算法,对安装铅芯橡胶隔震支座的钢筋混凝土框架隔震结构进行一体化优化设计,同步确定隔震器参数和上部结构构件截面几何尺寸。然后输入ElCentro(1940)、Hachinohe(1968)非脉冲型近断层地震动记录进行隔震结构一体化优化设计。计算结果表明,本文隔震结构优化设计得到的结果是合理的,与其他作者通过参数分析确定的隔震器最优参数具有可比性;对考虑脉冲型近断层地震动作用的隔震结构进行参数优化设计后,该隔震结构能同时满足脉冲型和普通非脉冲型近震作用的结构设计需求。反之,对非脉冲型近断层地震动作用的隔震结构进行参数优化设计后,该隔震结构不能满足脉冲型近震作用的设计需求。