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1.
层间隔震技术评述 总被引：37，自引：5，他引：32
祁皑 《地震工程与工程振动》2004,24(6):114-120
层间隔震结构是隔震技术的新发展,它将隔震层设置在建筑物某层柱子和楼板之间进行结构的地震反应控制。层间隔震结构在减震机理、振动特性以及设计方法等诸多方面有别于基础隔震结构和屋盖隔震结构。本文对层间隔震结构的适用范围、优点以及其在实际工程中的应用情况进行了综述,最后,指出了层问隔震结构需要进一步研究的问题。现有的研究成果和工程应用情况表明,层间隔震结构具有明确的减震效果,施工方便,是一种具有发展前途的减震体系。 相似文献
2.
Optimal cost‐effective topology of column bearings for reducing vertical acceleration demands in multistory base‐isolated buildings 
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下载免费PDF全文 Base‐isolation is regarded as one of the most effective methods for protecting the structural and nonstructural building elements from design level horizontal earthquake ground shaking. However, base‐isolation as currently practiced does not offer unlimited protection for these buildings, especially when the ground shaking includes a strong vertical component. The vulnerability of nonstructural systems in a base‐isolated building was made evident during recent shake table testing of a full‐scale five‐story base‐isolated steel moment frame where nonstructural system damage was observed following tests including vertical excitation. Past research efforts have attempted to achieve 3D isolation of buildings and nuclear structures by concentrating both the horizontal and vertical flexibility at the base of the building that are either quite limited or not economically viable. An approach whereby the vertical flexibility is distributed up the height of the building superstructure to passively reduce vertical acceleration demands in base‐isolated buildings is presented. The vertical flexibility is achieved by placing laterally restrained elastomeric ‘column’ bearings at one or more floor levels along the height of the building. To broadly investigate the efficacy of the vertically distributed flexibility concept and the trade‐off between mitigation and cost, a multi‐objective optimization study was conducted considering 3‐story, 9‐story, and 20‐story archetype buildings that aimed to minimize the median peak vertical floor acceleration demands and to minimize the direct cost of column bearings. Based on the results of the optimization study, a practical rule for determining the number of levels and locations of column bearings is proposed and evaluated. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
3.
Aseismic base isolation: review and bibliography 总被引：19，自引：0，他引：19
James M. Kelly 《Soil Dynamics and Earthquake Engineering》1986,5(4):202-216
The idea that a building can be uncoupled from the damaging effects of the ground movement produced by a strong earthquake has appealed to inventors and engineers for more than a century. Many ingenious devices have been proposed to achieve this result, but very few have been tried and the concept now generally referred to as base isolation or seismic isolation has yet to become acceptable to the engineering profession as a whole. Although most of the proposed systems are unacceptably complicated, in recent years a few practical systems have emerged and have been implemented. While some of these systems have been tested on large-scale shaking tables, none has to date been tested as built by a strong earth tremor. The shake testing and related static testing of full-scale components such as isolation bearings, however, has led to a certain degree of acceptance by the profession and it is possible that the number of practical implementations of base isolation will increase quite dramatically in the next few years.
This review summarizes much of the literature on theoretical aspects of seismic isolation, describes testing programmes and enumerates those isolation systems which have been used in buildings completed or under construction. It describes the characteristics of the various implemented systems with an indication of their range of applicability and some assessment of their development as backed by research. A bibliography of all papers published on the topic from 1900 to 1984 is included. The bibliography is as complete as possible, but, due to the rapid increase in research interest in the topic in the past few years, there may be a substantial degree of omission in the later years. 相似文献
4.
Hirokazu Iemura Touraj Taghikhany Sarvesh K. Jain 《Bulletin of Earthquake Engineering》2007,5(1):85-103
Seismic isolation is one of the effective methods to protect equipments. It helps to keep seismic response accelerations in
equipment below its allowable limits. Among different types of isolation systems, the combination of restoring spring and
slider, also called as resilient sliding isolation (RSI) system, is the one which has been effectively used for protection
of equipment. Principal design parameters for this type of isolation system are period of system (stiffness of spring) and
friction coefficient of slider. There may be number of combinations of these design parameters which can enable the isolated
equipment to remain functional during and after the predicted seismic event. The optimum design of RSI system can be considered
as the one which maintains the response acceleration in the equipment below its allowable limit and at the same time keeps
the relative displacement between floor and the equipment to the minimum. This study deals with optimum design of resilient
sliding system. First the RSI system is modeled analytically by (i) precise and (ii) simplified SDOF models. The accuracy
of the model is then validated by shaking table tests. The validated simplified SDOF model is then used to determine optimum
design parameters for different levels of allowable accelerations. Results show that the optimum period decreases and the
optimum friction coefficient increases with higher allowable acceleration. 相似文献
5.
James M. Kelly 《地震工程与结构动力学》1999,28(1):3-20
In the current code requirements for the design of base isolation systems for buildings located at near-fault sites, the design engineer is faced with very large design displacements for the isolators. To reduce these displacements, supplementary dampers are often prescribed. These dampers reduce displacements, but at the expense of significant increases in interstorey drifts and floor accelerations in the superstructure. An elementary analysis based on a simple model of an isolated structure is used to demonstrate this dilemma. The model is linear and is based on modal analysis, but includes the modal coupling terms caused by high levels of damping in the isolation system. The equations are solved by a method that avoids complex modal analysis. Estimates of the important response quantities are obtained by the response spectrum method. It is shown that as the damping in the isolation system increases, the contribution of the modal coupling terms due to isolator damping in response to the superstructure becomes the dominant term. The isolator displacement and structural base shear may be reduced, but the floor accelerations and interstorey drift are increased. The results show that the use of supplemental dampers in seismic isolation is a misplaced effort and alternative strategies to solve the problem are suggested. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
6.
隔震层位置与隔震支座选型 总被引：1，自引：0，他引：1
探讨隔震层的竖向设计位置,以期优化隔震设计,促进隔震技术的发展。隔震层设置在±0.00地板下和地下室板底相比:(1)在单层地下室部分不需设置隔震支座;(2)因减少地下室层的竖向荷载,竖向承载力的要求容易得到满足;(3)对于平面极不规则的结构,在±0.00板底隔震时,可以把上部结构分成几个平面相对比较规则的部分,因而隔震层扭转影响引起的位移可以减小;(4)对于文中算例,由于此3方面的原因,隔震支座选型后当隔震层处于±0.00地板下时可以降低隔震支座的费用达37.4%。对于平面尺寸大、平面极不规则的建筑结构把上部结构分割成若干规整的结构在首层地面以下进行隔震是一种经济可行的隔震方案。 相似文献
7.
A study of floor response spectra for a base-isolated multi-storey structure under sinusoidal and seismic ground excitations is carried out. Several base isolation systems including the laminated rubber bearing, the pure-friction, the resilient-friction, the Électricité de France and the sliding resilient-friction systems are considered. A sinusoidal ground acceleration and several earthquake accelerograms (including those of El Centro 1940, Pacoima Dam 1971 and Mexico City 1985) are used to evaluate the floor response spectra. The characteristics of the spectra generated by different base isolation systems are studied, and the results are compared with those for the fixed-base structure. It is shown that the structural contents can be protected against earthquakes by the use of properly designed base isolation systems. In particular, the laminated rubber bearing system appears to be remarkably effective in protecting the secondary systems under a variety of conditions. 相似文献
8.
A methodology for dynamic analysis of linear structure-foundation systems with local non-linearities
An efficient computational technique is presented for the dynamic analysis of large linear structural systems with local non-linearities. The earthquake response evaluation for many practical structures belongs to this class of problems. The technique provides a rational approach to the earthquake-resistant design of structure-foundation systems with predetermined non-linearities occurring along the structure-foundation interface. Various possibilities for base isolation systems are naturally fitted within the proposed framework. In particular, we address uplifting of the structure as a natural base isolation concept. We use the dynamic substructuring technique and an efficient numerical algorithm which accommodates non-proportional damping as a consistent way to reduce significantly the computational effort, which is in sharp contrast to the vast majority of ad-hoc simplified models used for the same purpose. A numerical example which demonstrates the vibration isolation effect when the uplifting of the concrete gravity dam occurs is also presented. 相似文献
9.
LQR control with frequency‐dependent scheduled gain for a semi‐active floor isolation system 下载免费PDF全文
下载免费PDF全文 Yundong Shi Tracy C. Becker Sachi Furukawa Eiji Sato Masayoshi Nakashima 《地震工程与结构动力学》2014,43(9):1265-1284
Floor isolation is an alternative to base isolation for protecting a specific group of equipment installed on a single floor or room in a fixed‐base structure. The acceleration of the isolated floor should be mitigated to protect the equipment, and the displacement needs to be suppressed, especially under long‐period motions, to save more space for the floor to place equipment. To design floor isolation systems that reduce acceleration and displacement for both short‐period and long‐period motions, semi‐active control with a newly proposed method using the linear quadratic regulator (LQR) control with frequency‐dependent scheduled gain (LQRSG) is adopted. The LQRSG method is developed to account for the frequency characteristics of the input motion. It updates the control gain calculated by the LQR control based on the relationship between the control gain and dominant frequency of the input motion. The dominant frequency is detected in real time using a window method. To verify the effectiveness of the LQRSG method, a series of shake table tests is performed for a semi‐active floor isolation system with rolling pendulum isolators and a magnetic‐rheological damper. The test results show that the LQRSG method is significantly more effective than the LQR control over a range of short‐period and long‐period motions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
10.
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
11.
Optimum isolation damping for minimum acceleration response of base-isolated structures subjected to stationary random excitation is investigated. Three linear models are considered to account for the energy dissipation mechanism of the isolation system: a Kelvin element, a linear hysteretic element and a standard solid linear element, commonly used viscoelastic models for isolation systems comprising natural rubber bearings and viscous dampers. The criterion selected for optimality is the minimization of the mean-square floor acceleration response. The effects of the frequency content of the excitation and superstructure properties on the optimum damping and on the mean-square acceleration response are addressed. The study basically shows that the attainable reduction in the floor acceleration largely depends on the energy dissipation mechanism assumed for the isolation system as well as on the frequency content of the ground acceleration process. Special care should be taken in accurately modelling the mechanical behaviour of the energy dissipation devices. 相似文献
12.
Seismic isolation technique is increasingly used both for the design of new buildings and for the seismic retrofit of existing buildings. Nevertheless, so far, little attention has been paid on the collapse capacity of these structures, mainly because it requires refined nonlinear models and careful consideration of different sources of uncertainties. To fill this gap, a set of collapse fragility functions for existing reinforced concrete-frame buildings, designed for gravity loads only and then retrofitted with different isolation systems (including rubber-based and friction-based isolation systems), are derived in this study. For completeness, buildings with low and high seismic resistance are also considered. Collapse fragility functions are derived through incremental dynamic analysis, considering different collapse conditions both for isolation system and superstructure. For each case study building, mean and dispersion values are obtained considering both aleatory and epistemic uncertainties, due to record-to record and model variability, respectively. Finally, some comments on the possible use of the results of this study for practical applications are made. 相似文献
13.
For the public welfare and safety, buildings such as hospitals, industrial facilities, and technology centers need to remain
functional at all times; even during and after major earthquakes. The values of these buildings themselves may be insignificant
when compared to the cost of loss of operations and business continuity. Seismic isolation aims to protect both the integrity
and the contents of a structure. Since the tolerable acceleration levels are relatively low for continued services of vibration-sensitive
high-tech contents, a better understanding of acceleration response behaviors of seismically isolated buildings is necessary.
In an effort to shed light to this issue, following are investigated via bi-directional time history analyses of seismically
isolated benchmark buildings subject to historical earthquakes: (i) the distribution of peak floor accelerations of seismically
isolated buildings subject to seismic excitations in order to find out which floors are likely to sustain the largest accelerations;
(ii) the influence of equivalent linear modeling of isolation systems on the floor accelerations in order to find out the
range of possible errors introduced by this type of modeling; (iii) the role of superstructure damping in reducing floor accelerations
of seismically isolated buildings with flexible superstructures in order to find out whether increasing the superstructure
damping helps reducing floor accelerations notably. Influences of isolation system characteristics and superstructure flexibility
are both taken into account. 相似文献
14.
Shiang‐Jung Wang Jenn‐Shin Hwang Kuo‐Chun Chang Chia‐Yi Shiau Wang‐Chuen Lin Mu‐Sen Tsai Jia‐Xiang Hong Yin‐Han Yang 《地震工程与结构动力学》2014,43(10):1443-1461
The rolling motion of mutually orthogonal rollers respectively sandwiched between two bearing plates in which one or both have V‐shaped sloping surfaces makes the sloped rolling‐type isolation device have an excellent in‐plane seismic isolation performance. In this study, the sloped rolling type isolation device in which a single roller moves between two V‐shaped sloping surfaces along each principle horizontal direction is refined by incorporating multi‐roller, built‐in damping, and pounding prevention mechanisms. The associated dynamic behavior is further clarified, and a simplified twin‐flag hysteretic model, which can be easily applied in most commercial computational tools is then proposed. Seismic simulation tests on the refined isolation devices (i.e. the sloped multi‐roller isolation devices) with different design parameters such as sloping angles of bearing plates and built‐in damping capabilities, together with a raised floor system by employing the sloped multi‐roller isolation devices, were conducted. Not only is the efficiency of the sloped multi‐roller isolation devices in seismically protecting the important objects, but also the practicability and accuracy of the proposed simplified numerical model in predicting the seismic responses of the sloped multi‐roller isolation devices is experimentally verified. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
15.
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
16.
Critical non‐structural equipments, including life‐saving equipment in hospitals, circuit breakers, computers, high technology instrumentations, etc., are vulnerable to strong earthquakes, and the failure of these equipments may result in a heavy economic loss. In this connection, innovative control systems and strategies are needed for their seismic protections. This paper presents the performance evaluation of passive and semi‐active control in the equipment isolation system for earthquake protection. Through shaking table tests of a 3‐story steel frame with equipment on the first floor, a magnetorheological (MR)‐damper together with a sliding friction pendulum isolation system is placed between the equipment and floor to reduce the vibration of the equipment. Various control algorithms are used for this semi‐active control studies, including the decentralized sliding mode control (DSMC) and LQR control. The passive‐on and passive‐off control of MR damper is used as a reference for the discussion on the control effectiveness. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
17.
Dongyao Tan 《地震工程与结构动力学》1998,27(7):661-672
The concept of envelope system for a given dynamic system is proposed in this paper which refers to those systems whose module of transfer function in the whole range of frequency domain is always bigger than that of a given system. This concept opens a new way to study the problems of robust design and modelling for dynamic systems. The condition that an envelope system has to satisfy is rendered as the determination of the positiveness of a real polynomial function and Sturm's sequence method is used to establish an easily implemented criterion for evaluating the positiveness of the polynomial in terms of its coefficients. The optimization for the envelope system is expressed as the minimization of the 2-norm of its transfer function and simplex method is employed to search for the optimal solution. Two dynamic systems are used to illustrate the optimal design for the envelope systems of some of their responses. © 1998 John Wiley & Sons, Ltd. 相似文献
18.
Seismic response of 20‐story base‐isolated and fixed‐base reinforced concrete structural wall buildings at a near‐fault site 下载免费PDF全文
下载免费PDF全文 This paper investigates numerically the seismic response of six seismically base‐isolated (BI) 20‐story reinforced concrete buildings and compares their response to that of a fixed‐base (FB) building with a similar structural system above ground. Located in Berkeley, California, 2 km from the Hayward fault, the buildings are designed with a core wall that provides most of the lateral force resistance above ground. For the BI buildings, the following are investigated: two isolation systems (both implemented below a three‐story basement), isolation periods equal to 4, 5, and 6 s, and two levels of flexural strength of the wall. The first isolation system combines tension‐resistant friction pendulum bearings and nonlinear fluid viscous dampers (NFVDs); the second combines low‐friction tension‐resistant crosslinear bearings, lead‐rubber bearings, and NFVDs. The designs of all buildings satisfy ASCE 7‐10 requirements, except that one component of horizontal excitation, is used in the 2D nonlinear response history analysis. Analysis is performed for a set of ground motions scaled to the design earthquake and to the maximum considered earthquake (MCE). At both the design earthquake and the MCE, the FB building develops large inelastic deformations and shear forces in the wall and large floor accelerations. At the MCE, four of the BI buildings experience nominally elastic response of the wall, with floor accelerations and shear forces being 0.25 to 0.55 times those experienced by the FB building. The response of the FB and four of the BI buildings to four unscaled historical pulse‐like near‐fault ground motions is also studied. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
19.
Petros Komodromos Panayiotis C. Polycarpou Loizos Papaloizou Marios C. Phocas 《地震工程与结构动力学》2007,36(12):1605-1622
Numerical simulations and parametric studies have been used to investigate the influence of potential poundings of seismically isolated buildings with adjacent structures on the effectiveness of seismic isolation. Poundings are assumed to occur at the isolation level between the seismically isolated building and the surrounding moat wall. After assessing some common force‐based impact models, a variation of the linear viscoelastic impact model is proposed to avoid tensile impact forces during detachment, while enabling the consideration of permanent plastic deformations at the vicinity of the impact. A large number of numerical simulations of seismically isolated buildings with different characteristics have been conducted under six earthquake excitations in order to investigate the influence of various design parameters and conditions on the peak floor accelerations and interstorey deflections during poundings. The numerical simulations demonstrate that poundings may substantially increase floor accelerations, especially t the base floor where impacts occur. Higher modes of vibration are excided during poundings, increasing the interstorey deflections, instead of retaining an almost rigid‐body motion of the superstructure, which is aimed with seismic isolation. Impact stiffness seems to affect significantly the acceleration response at the isolation level, while the displacement response is more insensitive to the variation of the impact stiffness. Finally, the results indicate that providing excessive flexibility at the isolation system to minimize the floor accelerations may lead to a building vulnerable to poundings, if the available seismic gap is limited. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
20.
桥梁作为交通系统中的生命线工程,其抗震性能问题尤为重要。桥梁减隔震技术主要通过减隔震装置来降低结构的地震损伤,目前已发展成为提高强震区桥梁抗震能力的重要措施。为促进减隔震技术在中国桥梁工程领域的进一步发展,首先总结减隔震桥梁的设计方法,归纳其地震反应和震害情况,对采用不同减隔震装置桥梁的非线性动力性能、减隔震效果、地震随机响应、易损性及性能优化方法等研究情况进行梳理;其次,概述减隔震技术在斜交桥、曲线桥及铁路桥梁中的应用情况与研究进展,并介绍新型韧性抗震设计理念在桥梁工程领域中的应用情况和发展前景;最后,总结减隔震桥梁的试验研究情况,指出目前减隔震桥梁研究中的不足和发展趋势。 相似文献