扇形铅黏弹性阻尼器综合设计及加固框架抗震性能分析

为研究扇形铅黏弹性阻尼器与加固框架结构之间的匹配关系及其对加固框架抗震性能的影响规律,用ABAQUS软件建立了对比空框架和加固框架的精细化有限元模型,结合试验试件骨架曲线及破坏形态验证了其合理性。提出扇形铅黏弹性阻尼器加固框架的综合设计原则,设定阻尼器扇形有效半径与框架柱净高之比为设计尺寸比,在此基础上,对不同设计尺寸比的加固框架进行对比分析。分析结果表明,合理设置的扇形铅黏弹性阻尼器可以显著提高加固框架的抗震性能,保护梁柱节点核心区;当设计尺寸比取值超过0.24时,会导致加固试件较早达到峰值荷载,但其后承载力又急剧衰减;建议扇形铅黏弹性阻尼器加固框架的设计尺寸比宜控制在0.1~0.2之间,实际设计中应依据不同加固需求选取相应的设计尺寸比。     

Evaluation of a developed bypass viscous damper performance

In this study, the dynamic behavior of a developed bypass viscous damper is evaluated. Bypass viscous damper has a flexible hose as an external orifice through which the inside fluid transfer from one side to the other side of the inner piston. Accordingly, the viscosity coefficient of the damper can be adjusted using geometrical dimensions of the hose. Moreover, the external orifice acts as a thermal compensator and alleviates viscous heating of the damper. According to experimental results, Computational Fluid Dynamic (CFD) model, a numerical formula and the simplified Maxwell model are found and assessed; therefore, the verification of numerical and computational models are evaluated for simulating. Also, a simplified procedure is proposed to design structures with bypass viscous dampers. The design procedure is applied to design an 8-story hospital structure with bypass viscous dampers, and it is compared with the same structure, which is designed with concentric braces and without dampers. Nonlinear time history analyses revealed that the hospital with viscous damper experiences less structural inelastic demands and fewer story accelerations which mean fewer demands on nonstructural elements. Moreover, seismic behaviors of nonstructural masonry claddings are also compared in the cases of hospital structure with and without dampers.     

Risk‐based optimal retrofit of a tall steel building by using friction dampers

Friction dampers, whose configuration is optimized on the basis of the probabilistic seismic loss associated with a building's damage due to ground motion, were utilized in this study to optimally retrofit a 15‐story steel structure. In line with the concept of performance‐based earthquake engineering (PBEE), a decision‐making procedure based on the monetary seismic loss was incorporated for optimizing the dampers' configuration. A nonlinear numerical model was initially established for representing the structure. In this regard, a brace–damper system was modeled with the buckling of brace elements being addressed accurately and by representing the friction damper's load–displacement relationship on the basis of laboratory evidences. By monitoring the structural deformations in two different response levels, two patterns were established for the distribution of the dampers' strengths throughout the structure, and a number of retrofit alternatives were proposed subsequently. By using incremental dynamic analysis and following the PBEE methodology, the annualized loss (AL), which accounts for all potential damage states in the building and a broad range of seismic intensities, was calculated for each alternative frame. The AL is regarded as a decision variable upon which the best damper configuration is selected. Revealing conclusions were finally made regarding optimal configuration of the damper–brace system. Copyright © 2011 John Wiley & Sons, Ltd.     

Optimization layout of viscous dampers and its application in retrofitting of a high-rise steel structure

阻尼器优化布置是结构减震设计过程中的重要环节，通常需要通过多次动力响应计算来完成。为此，提出了一种通过结构静力分析确定阻尼器合理布置位置的方法，并能够快速计算出优化方案的附加阻尼比。将该方法应用于一栋位于日本东京都新宿区29层钢结构建筑的减震加固设计中，分析了该建筑的强震观测系统在日本“311地震”中采集到的部分楼层加速度时程数据，并基于分析结果验证了所建立的非线性数值分析模型的可靠性。采用所提方法对结构进行减震加固，得到双向共64个阻尼器的优化布置方案及其附加阻尼比，并通过动力方法对结果进行了验证。同时针对长周期及长持时特性的地震波，对减震结构进行动力弹塑性时程分析，评估其抗震性能。分析结果表明：减震优化方案的减震效果明显，结构整体地震反应和构件损伤较非减震方案都大大减小；减震优化方案有效改善了高层钢结构楼层变形不均匀的情况，层间位移角均满足小于1/100的性能要求；通过减震优化后大部分钢支撑和钢梁的塑性率都降低至小于1。     

黏滞阻尼器的优化布置及其在高层钢结构加固中的应用

阻尼器优化布置是结构减震设计过程中的重要环节,通常需要通过多次动力响应计算来完成。为此,提出了一种通过结构静力分析确定阻尼器合理布置位置的方法,并能够快速计算出优化方案的附加阻尼比。将该方法应用于一栋位于日本东京都新宿区29层钢结构建筑的减震加固设计中,分析了该建筑的强震观测系统在日本“311地震”中采集到的部分楼层加速度时程数据,并基于分析结果验证了所建立的非线性数值分析模型的可靠性。采用所提方法对结构进行减震加固,得到双向共64个阻尼器的优化布置方案及其附加阻尼比,并通过动力方法对结果进行了验证。同时针对长周期及长持时特性的地震波,对减震结构进行动力弹塑性时程分析,评估其抗震性能。分析结果表明：减震优化方案的减震效果明显,结构整体地震反应和构件损伤较非减震方案都大大减小;减震优化方案有效改善了高层钢结构楼层变形不均匀的情况,层间位移角均满足小于1/100的性能要求;通过减震优化后大部分钢支撑和钢梁的塑性率都降低至小于1。     

Proposed Relationship for Proper Shear Strength of Elliptical Damper Based on Its Geometrical Parameters

Vertical link beam as a practical yielding damper is a kind of passive control device which dissipates seismic energy and thus reduces the rate of damage to structures through in-plane shear deformations. Proper stiffness, ductility and significant energy dissipation of these dampers together with their practical advantages justify their widespread experimental and numerical research. In this paper, a total of 42 elliptical dampers (vertical link beams with elliptical cross sections) in various lengths and thicknesses are modeled using the ABAQUS finite element software and finally a design relationship for this damper is presented based on the above mentioned geometrical parameters using pushover analysis. The accuracy of the proposed relationship is studied by applying various layouts of designed dampers on two types of chevron bracings to improve their performance and obtain proper energy dissipation without brace buckling. The equivalent viscous damping ratios of 32–33% obtained for elliptical dampers indicate high increase in energy dissipation capability.     

地震作用下某高层结构MTMD减震控制研究

通过数值模拟研究了地震作用下高层结构多个调谐质量阻尼器(MTMD)减震控制。根据实际工程,利用国际通用软件ETABS建立了结构三维有限元模型,进行了动力特性的分析,得到了结构的前几阶频率;根据不同场地类型,选取了4条典型的地震波;研究了调谐质量阻尼器(TMD)的参数选取和有限元的模拟;运用时程分析方法,分别研究了不同地震作用下高层结构有无控制下的反应。研究结果表明,MTMD对高层结构的减震控制效果明显,场地类型对减震控制效果有一定的影响。所获得的结果为高层结构减震控制设计提供参考和依据。     

基于性能的抗震加固方法在框架结构中的应用

对于抗震构造措施不满足现行规范的既有钢筋混凝土结构,采用传统方法加固不便于工程实施。以某医疗建筑为例,介绍了基于性能的抗震加固设计思路及采取消能减震技术提高抗震性能的方法。主要针对结构设防目标和设计原则、阻尼器合理布置方案及减震效果等问题进行了探讨。研究认为:提出的抗震加固设计方法更为经济合理,消能减震结构的抗震性能明显提高时,抗震构造要求可适当降低;合理布置阻尼器不仅可以降低水平剪力、层间变形,还可以控制结构的扭转反应。     

Seismic response of base isolating systems with U-shaped hysteretic dampers

This paper proposes a base isolating system to reduce the seismic demands of low- or medium-rise structures and experimentally investigates its seismic response using shake-table tests. The base isolating system considered in this study consists of laminated-rubber bearings and U-shaped hysteretic (UH) dampers which are made of high toughness steel (HTS) and are machined with slotted holes to increase their deformation capacities. A base isolated 2-story specimen for shake-table tests was first designed and cyclic tests of laminated-rubber bearings and UH dampers implemented in the base isolating systems were then carried out. The component test for the laminated-rubber bearings shows typically low lateral stiffness with enough vertical stiffness to carry gravity loads. The test results for the UH dampers demonstrate that the use of HTS material and the introduction of the slotted holes details increase deformation capacities by inducing uniform stress distribution along a UH damper. Finally, shake-table tests were performed using specimens shaken with increasing ground acceleration records. The shake-table tests show that the proposed base isolating system with UH dampers limits the seismic demands of a base isolated structure by lengthening its structural period, concentrating displacement demands on the base isolating floor and adding seismic energy dissipation from the UH dampers.     

设置钢阻尼器钢结构的有限元分析

借助ABAQUS有限元软件,对设置钢阻尼器的钢结构进行了地震动荷载作用下的有限元分析,得出钢阻尼器能为结构提供附加抗侧刚度和附加阻尼,耗散输入的地震能量,保护主体结构,减震效果显著的结论。     

形状记忆合金被动阻尼器及结构地震反应控制试验研究和分析

利用形状记忆合金(ShapeMemoryAlloy,简称SMA)的超弹性特性,本文提出了一种新型SMA阻尼器,将其安装在结构层间,抵抗结构地震作用。通过对阻尼器的构造设计,使其中的NiTi丝在结构振动过程中始终处于受拉状态,避免了合金丝的受压屈曲。文中首先针对一种直径为1.2mm的NiTi丝的超弹性特性进行了性能试验。试验结果表明,NiTi丝的超弹性滞回特性受其加载频率及循环圈数的影响,但当加载频率大于2Hz,加载循环圈数大于15圈后,该丝的超弹性滞回曲线趋于稳定。然后,将本文提出的SMA阻尼器安装在一个5层钢框架结构模型上进行了地震模拟振动台试验,验证了该SMA阻尼器可以有效减小结构的地震反应。最后,采用自回归(ARX)模型对无控和有控结构建模,分别采用最小二乘法和Kalman滤波法识别得到了无控结构和有控结构的ARX模型的参数,并由此进一步分析得到了无控和有控结构的各阶模态参数。     

Seismic retrofit of a high‐rise steel moment‐resisting frame using fluid viscous dampers

The Tall Building Initiative project of Pacific Earthquake Engineering Research Center has been expanded to investigate the seismic performance and possible retrofit of existing tall buildings. A candidate 35‐story steel building with representative details from the early 1970s was analyzed following several guidelines, which revealed a wide range of potential inadequacies. Thus, a two‐level retrofit approach was examined that focused on achieving the collapse prevention limit state under the major basic safety earthquake (BSE‐2E) hazard level prescribed by ASCE 41. This paper focused on a Level‐2 retrofit that used fluid viscous dampers to augment Level‐1 retrofits. For this approach, feasible damper locations and overall effective damping ratios were first evaluated through a series of preliminary studies, and then a two‐phase design method was used to refine the distribution and mechanical properties of the dampers. Thorough assessments of the refined design were carried out following several design guidelines, including ASCE 41, FEMA 351, and FEMA P‐58. The results indicated that the proposed retrofit method of using fluid viscous dampers could achieve the retrofit goal and provide a cost‐effective means of improving the structural behavior and reducing economic losses in a major seismic event.     

建筑结构中阻尼器消能减震设计关键技术的探讨

阻尼器能有效地实现结构的消能减震,在中国也逐渐得到应用。为更好地促进阻尼器在我国的应用,解决当前对阻尼器应用的一些认识不足问题,结合主要由现代设计集团完成的带阻尼器消能减震结构工程应用情况,介绍了位移型和速度型阻尼器及其应用情况。结合国内工程界对阻尼器的研究和工程应用情况,探讨了一些阻尼器应用的关键设计技术问题,尤其是关于国内外抗震规范系统性的差异引起的阻尼器应用设计问题、采用阻尼器结构的计算分析技术、阻尼器的侧向稳定问题等,提出解决方法和今后研究的方向,供广大工程人员讨论。     

U型金属阻尼器受力性能和数值模拟分析方法研究

首先收集了17个U型金属阻尼器的试验数据,并对采用不同类型钢材的U型金属阻尼器的面内受力性能进行了分析和比较。在此基础上,研究了分别适用于构件层次分析和结构层次分析的U型金属阻尼器精细有限元模型和简化有限元模型的建模方法。结果表明:采用实体单元建立的精细有限元模型,既可较准确地模拟出U型金属阻尼器的荷载-位移滞回关系,又可以较好地反映其微观损伤模式;建议的U型金属阻尼器初始刚度和屈服荷载计算公式预测值与试验结果较接近,且偏于安全,可用于简化模型骨架参数的确定;采用建议的简化有限元模型分析得到的试件荷载-位移滞回曲线与试验结果吻合较好。     

减震装置的移位原理及其在黏滞阻尼减震结构设计中的应用

现有消能减震结构的设计方法在确定减震关键参数及其空间分配时需要繁琐的迭代试算.为解决此问题,基于减震结构消能减震装置的"移位"原理,提出了减震结构的系统化设计方法,可高效地实现减震结构中阻尼器的参数确定与分配.基于广义单自由度理论提出了减震主自由度的概念,进而发现了减震结构中消能减震装置的"移位"原理,即若要将减震装置...     

Investigation of MRS and SMA Dampers Effects on Bridge Seismic Resistance Employing Analytical Models

This study dealt with investigating the seismic performance of the smart and shape memory alloy (SMA) and magnets plus rubber-spring (MRS) dampers and their effects on the seismic resistance of multiple-span simply supported bridges. The rubber springs in the MRS dampers were pre-compressed. For this aim, a set of experimental works was performed together with developing nonlinear analytical models to investigate dynamic responses of the bridges subjected to earthquakes. Fragility analysis and probabilistic assessment were conducted to assess the seismic performance for the overall bridge system. Fragility curves were then generated for each model and were compared with those of as-built. Results showed dampers could increase the seismic capacity of bridges. Furthermore, from system fragility curves, use of damper models reduced the seismic vulnerability in comparison to the as-built bridge model. Although the SMA damper showed the best seismic performance, the MRS damper was the most appropriate one for the bridge in that the combination of magnetic friction and pre-compressed rubber springs was cheaper than the shape memory alloy, and had the similar capability of the damper.     

基于极点配置算法的黏滞阻尼器优化设计

为克服常用极点配置算法的局限性,提出基于实模态空间解耦的极点配置算法,该算法求得的反馈增益矩阵中位移反馈增益始终为零,符合黏滞阻尼器特性。基于该反馈增益矩阵采用等效最优控制法进行参数优化设计,并提出基于阻尼器耗散能量的位置优化设计方法。在上述研究的基础上给出了黏滞阻尼器优化设计流程,并以某20层实际结构进行数值模拟,分析结果表明,被动控制系统性能与对应主动控制系统的性能相近,达到预期效果,验证该设计流程的有效性与正确性。     

基于高强钢碟簧和复合摩擦材料的自复位消能减震阻尼器受力性能与试验研究

为提高建筑结构抗震韧性,实现震时响应可控,震后易修复的性能目标,提出一种基于高强钢碟簧和复合摩擦材料的自复位消能减震阻尼器,给出一种基本构造方案,分析阻尼器不同阶段的工作原理,理论推导滞回曲线及各阶段刚度、承载力计算公式。通过多次往复加载试验,对碟簧和摩擦片的基本性能,以及多次地震作用下阻尼器的滞回性能和低周疲劳性能进行了考察。试验结果表明,高强钢碟簧性能稳定,复合摩擦材料耗能能力优异;基于两者组合的自复位消能减震阻尼器具有良好的可调节刚度、承载力以及优异的自复位性能;阻尼器滞回耗能稳定,可实现震后功能恢复,低周疲劳性能好。提出的阻尼器工作过程中各阶段刚度及承载力计算公式与试验结果吻合较好,可为工程设计提供参考。     

Z型支撑分级屈服阻尼器抗震性能研究

为实现阻尼器分级耗能屈服,文章提出一种基于Q235钢材由内部Z型支撑及两侧开孔钢板组合形成分级屈服金属阻尼器。通过对3组不同肢高Z型支撑分级屈服阻尼器施加水平低周往复位移加载,进行试验与ABAQUS模拟抗震滞回性能分析,探究Z型支撑分级屈服阻尼器耗能状态及抗震性能,揭示该阻尼器的耗能机理与破坏模态。研究结果表明：阻尼器可实现分级屈服,随着肢高减小,Z型支撑分级屈服阻尼器能更有效提高主体结构抗震滞回性能。     

SMA复合摩擦阻尼器在网架结构中的减振效果分析

将SMA复合摩擦阻尼器用作空间网架结构的耗能减振装置,探讨了其在空间结构中的减振控制分析方法。介绍了SMA复合摩擦阻尼器的工作原理和理论模型,建立了网架结构减振控制的运动方程。地震作用下某网架结构减振控制的数值模拟结果表明,SMA复合摩擦阻尼器可有效降低结构地震响应,较之纯摩擦阻尼器和纯SMA阻尼器,减振效果更为优良。