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1.
Isolation bearings and dampers are often installed between piers and superstructures to reduce the seismic responses of bridges under large earthquakes. This paper presents a novel steel damper for bridges. The damper employs steel plates as energy dissipation components, and adopts a vertical free mechanism to achieve a large deformation capacity. Quasi-static tests using displacement-controlled cyclic loading and numerical analyses using a finite element program called ABAQUS are conducted to investigate the behavior of the damper, and a design methodology is proposed based on the tests and numerical analyses. Major conclusions obtained from this study are as follows:(1) the new dampers have stable hysteresis behavior under large displacements;(2) finite element analyses are able to simulate the behavior of the damper with satisfactory accuracy; and(3) simplified design methodology of the damper is effective. 相似文献
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Magneto‐rheological (MR) dampers are a promising device for seismic hazard mitigation because their damping characteristics can be varied adaptively using an appropriate control law. During the last few decades researchers have investigated the behavior of MR dampers and semi‐active control laws associated with these types of dampers for earthquake hazard mitigation. A majority of this research has involved small‐scale MR dampers. To investigate the dynamic behavior of a large‐scale MR damper, characterization tests were conducted at the Lehigh Network for Earthquake Engineering Simulation equipment site on large‐scale MR dampers. A new MR damper model, called the Maxwell Nonlinear Slider (MNS) model, is developed based on the characterization tests and is reported in this paper. The MNS model can independently describe the pre‐yield and post‐yield behavior of an MR damper, which makes it easy to identify the model parameters. The MNS model utilizes Hershel–Bulkley visco‐plasticity to describe the post‐yield non‐Newtonian fluid behavior, that is, shear thinning and thickening behavior, of the MR fluid that occurs in the dampers. The predicted response of a large‐scale damper from the MNS model along with that from existing Bouc–Wen and hyperbolic tangent models, are compared with measured response from various experiments. The comparisons show that the MNS model achieves better accuracy than the existing models in predicting damper response under cyclic loading. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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《地震工程与工程振动(英文版)》2015,(1)
This study proposes a novel mild steel damper with non-uniform vertical slits. The infl uence of different shapes of vertical slits of the core energy plate on the energy dissipation and buckling resistance capacities is analyzed. Based on the theoretical analysis, formulas of key parameters of the dampers, including the elastic lateral stiffness, shear bearing capacity and yield displacement, are derived. The effectiveness of the proposed damper is demonstrated through pseudo static tests on four 0.25-scale specimens. Performance of these dampers, i.e. cyclic deformation, stress distribution, energy dissipation capacity, etc., are presented and discussed. Using the numerical models of dampers calibrated through test data, earthquake time-history analyses were conducted, and it is observed that the dampers significantly reduce the seismic responses of the prototype frame and have a desirable energy dissipation capacity. 相似文献
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Buckling is usually conceived as an unstable structural behavior leading to lateral instability of axially loaded members, if not properly supported. However, a pre‐bent strip would become an excellent seismic energy‐dissipative device if it is deformed in a guided direction and range. Geometrically large lateral deformation of the steel strips in buckling leads to inelastic behavior of the material and dissipates energy as a consequence. The purpose of this study is to propose a new type of seismic damper in the form of braces based on pre‐bent steel strips. The nonlinear elastic stiffness of monotonously loaded pre‐bent strips in both compression and tension is derived. The energy‐dissipative characteristics of the proposed damping device are investigated via component tests under cyclic loads. Experimental results indicate that the force–displacement relationship of pre‐bent strips in cyclic loads exhibits mechanical characteristics of displacement‐dependent dampers. A series of seismic performance tests has been conducted further to verify the feasibility and effectiveness of using the proposed device as seismic dampers. Encouraging test results have been obtained, suggesting feasibility of the proposed device for earthquake‐resistant design. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Domenico Altieri Enrico Tubaldi Marco De Angelis Edoardo Patelli Andrea Dall’Asta 《Bulletin of Earthquake Engineering》2018,16(2):963-982
Viscous dampers are widely employed for enhancing the seismic performance of structural systems, and their design is often carried out using simplified approaches to account for the uncertainty in the seismic input. This paper introduces a novel and rigorous approach that allows to explicitly consider the variability of the intensity and characteristics of the seismic input in designing the optimal viscous constant and velocity exponent of the dampers based on performance-based criteria. The optimal solution permits controlling the probability of structural failure, while minimizing the damper cost, related to the sum of the damper forces. The solution to the optimization problem is efficiently sought via the constrained optimization by linear approximation (COBYLA) method, while Subset simulation together with auxiliary response method are employed for the performance assessment at each iteration of the optimization process. A 3-storey steel moment-resisting building frame is considered to illustrate the application of the proposed design methodology and to evaluate and compare the performances that can be achieved with different damper nonlinearity levels. Comparisons are also made with the results obtained by applying simplifying approaches, often employed in design practice, as those aiming to minimize the sum of the viscous damping constant and/or considering a single hazard level for the performance assessment. 相似文献
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为研究复合材料电气设备抗震性能与减震技术应用效果,对特高压复合支柱材料绝缘子进行了抗震与减震地震模拟振动台试验,研究了设备动力特性和地震响应。白噪声试验结果表明:该复合材料支柱绝缘子在安装减震器后第1阶频率由1.11 Hz降低到1.04 Hz,表明减震器对设备结构的整体刚度影响较小。3种地震波试验结果表明:设备地震响应与地震动峰值加速度在抗震试验中呈线性变化关系,但在减震试验的应力响应中呈非线性变化关系;设备安装减震器后,试验地震动峰值加速度越大,减震效率越高,最高达到了66.32%;而位移减震率与地震动峰值加速度无明显规律,最大位移减震率为49.36%。试验研究结果表明:试验设备安装减震器后抗震性能得到显著提升,为复合材料电气设备抗震性能研究与减震技术应用提供了参考依据。 相似文献
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在大震或特大震下,黏滞阻尼器可能因某个极限状态的出现而发生破坏。现有在斜拉桥上设置黏滞阻尼器的研究多集中在阻尼器的参数优化上,很少考虑到阻尼器失效对斜拉桥抗震性能的影响。针对这一问题,以某三塔斜拉桥为背景,利用OpenSees平台建立斜拉桥有限元模型和可以考虑承载力及行程极限的黏滞阻尼器模型;分析黏滞阻尼器的阻尼系数和阻尼指数对斜拉桥地震响应的影响,确定阻尼器参数的取值;对不安装阻尼器、安装不考虑极限状态及考虑极限状态阻尼器等多种工况的斜拉桥进行非线性时程分析,对比各工况斜拉桥的地震响应。分析结果表明,在大震下,考虑极限状态阻尼器的耗能能力及减震效果将显著降低;不考虑阻尼器达到极限状态后失效的情况将高估耗能减震设计斜拉桥的抗震能力。 相似文献
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Buildings are continually subject to dynamic loads, such as wind load, seismic ground motion, and even the load from internal utility machines. The recent trend of constructing more flexible high‐rise buildings underscores the importance of including viscoelastic dampers in building designs. Viscoelastic dampers are used to control the dynamic response of a building. If the seismic design is based only on the linear response spectrum, considerable error may occur when calculating the seismic response of a building; rubber viscoelastic dampers show non‐linear hysteretic damping that is quite different from viscous damping. This study generated a non‐linear response spectrum using a non‐linear oscillator model to simulate a building with viscoelastic dampers installed. The parameters used in the non‐linear damper model were obtained experimentally from dynamic loading tests. The results show that viscoelastic dampers effectively reduce the seismic displacement response of a structure, but transmit more seismic force to the structure, which essentially increases its seismic acceleration response. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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安装形状记忆合金阻尼器的剪力墙结构抗震性能分析 总被引：1，自引：0，他引：1
为减轻钢筋混凝土剪力墙连梁的地震后永久性损伤,同时保持连梁的耗能机制,本文提出在剪力墙连梁中安装新型形状记忆合金(Shape Memory Alloy,简称SMA)阻尼器,并研究该阻尼器对剪力墙结构地震响应的减震效果。通过一幢12层剪力墙结构地震反应的时程分析,研究了SMA阻尼器的附加刚度比和屈服位移比两项特征参数对结构地震反应控制效果的影响规律。计算分析结果表明,当附加刚度比为0.04～0.05,屈服位移比为0.4～0.5时,可以获得较好的减震效果。 相似文献
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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
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Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all types of dampers are designed by the same procedure, actual seismic performance of the building may differ from one to the others. In this study, a nine-story benchmark steel building is established, and three different and typical types of dampers are designed according to the Chinese Building Code to realize structural vibration control under strong earthquake excitation. The seismic response of the prototype building equipped with a viscoelastic damper, viscous damper and buckling-restrained brace(BRB) subjected to 10 earthquake records are calculated, and Incremental Dynamic Analysis(IDA) is performed to describe progressive damage of the structure under increasing earthquake intensity. In the perspective of fragility, it shows that the viscoelastic damper has the highest collapse margin ratio(CMR), and the viscous damper provides the best drift control. Both the BRB and viscoelastic dampers can effectively reduce the floor acceleration responses in the mid-rise building. 相似文献
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In this study, several mass dampers were designed and fabricated to suppress the seismic responses of a ¼‐scale three‐storey building structure. The dynamic properties of the dampers and structure were identified from free and forced vibration tests. The building structure with or without the dampers was, respectively, tested on a shake table under the white noise excitation, the scaled 1940 El Centro earthquake and the scaled 1952 Taft earthquake. The dampers were placed on the building floors using the sequential procedure developed by the authors in previous studies. Experimental results indicated that the multiple damper system is substantially superior to a single tuned mass damper in mitigating the floor accelerations even though the multiple dampers are sub‐optimal in terms of tuning frequency, damping and placement. These results validated the sequential procedure for placement of the multiple dampers. The structure was also analysed numerically based on the shake table excitation and the identified structure and damper parameters for all test cases. Numerical and experimental results are in good agreement, validating the dynamic properties identified. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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The aseismic design of cable-stayed bridges in the transverse direction with newly proposed metallic dampers that can accommodate both longitudinal and transverse movement of the deck has recently been considered. This work focuses on developing a simplified method to design an appropriate metallic damper. The seismic performance of cablestayed bridges with different damper stiffness, main span lengths, tower shapes and types of deck in the transverse direction are investigated. The transverse displacement of the deck of a cable-stayed bridge increases significantly with the increment of the damper stiffness, which proves that the design of the damper stiffness is crucial. A simplified model considering the damper stiffness, cable system and tower in the transverse direction is developed to evaluate the period and lateral displacement of a complicated cable-stayed bridge. Based on the simplified model, a design method is proposed and assessed using two cable-stayed bridges as examples. The results show that metallic dampers can be designed with high efficiency, and the optimal ductility of the damper can be selected. 相似文献
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提出一种组合型减震结构,由钢框架、节点阻尼器和原结构连接组成,外附钢框架将节点阻尼器连接在原混凝土框架结构上形成的增设节点阻尼器的外附钢框架结构,节点阻尼器的剪切滞回变形可以减小结构自身需要消耗的能量,从而提高原结构抗震性能。对原混凝土结构和增设节点阻尼器的组合型结构进行了的振动台试验。通过分析结构在不同地震波激励下的加速度和位移响应,得出楼层加速度和层位移的减震效果。研究结果表明:该结构体系在小震作用下通过提高结构刚度来增强其抗震性能;在大震作用下则可借助节点阻尼器的变形耗能来提升结构耗能能力,结构加速度减震系数达到53%,层间位移减震系数高达72%,验证了增设节点阻尼器的外附钢框架结构的减震效果。 相似文献
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Concept and performance testing of a high‐capacity oil damper comprising multiple damper units 
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下载免费PDF全文 There has been a significant increase in the size of building structures in recent years. Huge structures such as high‐rise buildings and large‐domed stadiums require high‐performance structural control, including the use of high‐capacity dampers, especially in an earthquake‐prone country like Japan. The objective of the present study was the enhancement of both human and structural safety in such structures through the development of a rate‐dependent type of damper with a high damping capacity. Among the various available types of rate‐dependent dampers, the authors focused on the oil damper owing to its stable performance against long‐duration vibrations. The target maximum damping force was 6000 kN, which is higher than that of any existing oil damper utilized in building structures. The authors developed a novel concept for achieving this high capacity while maintaining the size of the damper within acceptable dimensions from an architectural point of view. The concept involves the use of multiple damper units that produce mechanically parallel damping forces spatially arranged in series. As a prototype, a 1500‐kN oil damper was fabricated by combining three 500‐kN dampers. The 1500‐kN prototype damper was conceived as a full‐scale prototype of a damper that is more slender than comparable commercially available dampers in Japan, and as a scaled model of the proposed 6000‐kN damper. Sinusoidal loading tests were conducted on the prototype damper using a frequency range of 0.1–1.5 Hz and a velocity range of 0.4–300 mm/s. The results confirmed that the damper produced the design damping forces. The results of earthquake loading tests also revealed that the damper exerted a stable damping force against a large earthquake and maintained its performance after the earthquake. The damper is particularly effective against earthquakes with long‐period components that could increase the temperature of a damper. This is afforded by its high heat capacity compared to conventional dampers. Considering that the proposed 6000‐kN damper will generate a damping force that is about 2–3 times that of the strongest conventional oil damper, existing manufacturer test machines would be inadequate for evaluating its full performance characteristics. To address this issue, the authors also propose a test method for evaluating the overall damping force. The method is premised on the fact that the characteristic feature of the proposed damper is its combination of multiple damper units. The overall performance is thus evaluated using the test results for the individual damper units while the other dampers are bypassed. This method was verified by the results of the abovementioned sinusoidal loading tests, with the error for the 1500‐kN prototype damper found to be less than 5%. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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薄弱层设置耗能阻尼器支撑的钢框架模型振动台试验 总被引：2，自引：0，他引：2
设计制作了一个五层钢框架模型,在其第一层、第三层和第五层薄弱层分别设置摩擦阻尼器、粘弹性阻尼器和粘弹性-摩擦阻尼器等三种耗能阻尼器支撑,进行了罕遇地震和多遇地震下的振动台试验。试验结果表明,耗能阻尼器支撑能够有效地控制结构的地震反应。 相似文献
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Semi‐active control of buildings and structures for earthquake hazard mitigation represents a relatively new research area. Two optimal displacement control strategies for semi‐active control of seismic response of frame structures using magnetorheological (MR) dampers or electrorheological (ER) dampers are proposed in this study. The efficacy of these displacement control strategies is compared with the optimal force control strategy. The stiffness of brace system supporting the smart damper is also taken into consideration. An extensive parameter study is carried out to find the optimal parameters of MR or ER fluids, by which the maximum reduction of seismic response may be achieved, and to assess the effects of earthquake intensity and brace stiffness on damper performance. The work on example buildings showed that the installation of the smart dampers with proper parameters and proper control strategy could significantly reduce seismic responses of structures, and the performance of the smart damper is better than that of the common brace or the passive devices. The optimal parameters of the damper and the proper control strategy could be identified through a parameter study. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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Direct design method based on seismic capacity redundancy for structures with metal yielding dampers 下载免费PDF全文
下载免费PDF全文 In this study, a direct static design method for structures with metal yielding dampers is proposed based on a new design target called the seismic capacity redundancy indicator (SCRI). The proposed method is applicable to the design of elastic‐plastic damped structures by considering the influence of damper on different structural performance indicators separately without the need for iteration or nonlinear dynamic analysis. The SCRI—a quantitative measure of the seismic capacity redundancy—is defined as the ratio of the seismic demand required by the target performance limit to the design seismic demand. Changes in the structural SCRI are correlated with the parameters of the supplemental dampers so that the dampers can be directly designed according to a given target SCRI. The proposed method is illustrated through application to a 12‐story reinforced‐concrete frame, and increment dynamic analysis is performed to verify the effectiveness of the proposed method. The seismic intensity corresponding to the target structural performance limit is regarded as a measure of the structural seismic capacity. The required seismic intensity increases after the structure is equipped with the designed metal yielding dampers according to the expected SCRI. It is concluded that the proposed method is easy to implement and feasible for performance‐based design of metal yielding dampers. 相似文献