Seismic design and assessment of structures with viscous dampers at limit state levels: Focus on probability of damage in devices

During large earthquakes, the seismic demand of viscous dampers may exceed their capacity. In this regard, current design codes must consider extreme conditions and preserve the damper at limit state levels. Here, by adjusting the damping coefficient, a procedure is introduced to mitigate device damages during severe earthquakes. To assess the procedure, 15 special moment resisting frames with a different number of stories (two, four, and eight) were designed by three methods: The recommended novel procedure, the seismic provisions of ASCE7, and the procedure proposed by Miyamoto et al. 1 for structures, installed with supplemental damping devices. A series of incremental dynamic analyses were then performed by modeling the limit state behavior of viscous dampers. Results indicated that the novel method reduces the damage probability of dampers as well as the maximum demands on the structure at different seismic hazard levels.     

Experimental evaluation of the seismic performance of steel MRFs with compressed elastomer dampers using large-scale real-time hybrid simulation

Real-time hybrid simulation combines experimental testing and numerical simulation, and thus is a viable experimental technique for evaluating the effectiveness of supplemental damping devices for seismic hazard mitigation. This paper presents an experimental program based on the use of the real-time hybrid simulation method to verify the performance-based seismic design of a two story, four-bay steel moment resisting frame (MRF) equipped with compressed elastomer dampers. The laboratory specimens, referred to as experimental substructures, are two individual compressed elastomer dampers with the remainder of the building modeled as an analytical substructure. The proposed experimental technique enables an ensemble of ground motions to be applied to the building, resulting in various levels of damage, without the need to repair the experimental substructures, since the damage will be within the analytical substructure. Statistical experimental response results incorporating the ground motion variability show that a steel MRF with compressed elastomer dampers can be designed to perform better than conventional steel special moment resisting frames (SMRFs), even when the MRF with dampers is significantly lighter in weight than the conventional MRF.     

非线性粘滞阻尼器在框架结构抗震加固设计中的应用

本文介绍了非线性粘弹性阻尼器的性能特点及消能减震原理。并以实际抗震加固工程为例对粘滞阻尼器、屈曲约束支撑及传统加固方法的特点进行了对比,并对粘滞阻尼器的设计流程及方法进行了阐述和探讨。     

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.     

地震区某学校教学楼消能减震加固研究

以汶川地震后重灾区一学校教学楼为研究对象,利用消能减震技术,对消能减震加固方案进行了设计,以提高其抗震安全性,使之满足建筑抗震设计规范的要求,为今后类似的建筑结构加固设计提供有益的参考。     

设置黏滞阻尼器的装配整体式框架结构抗震性能试验研究

为研究黏滞阻尼器对装配整体式框架结构抗震性能的影响,分别设计制作了1榀带黏滞阻尼器的装配整体式钢筋混凝土框架模型和普通装配整体式钢筋混凝土框架模型.对两模型进行了水平正弦激励荷载作用下的抗震性能试验,研究了两模型的滞回特性、耗能能力等.试验结果表明:设置黏滞阻尼器框架的滞回曲线较普通框架饱满,结构的耗能能力及附加阻尼比...     

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。     

Numerical study of seismic performance of steel moment-resisting frame with buckling-restrained brace and viscous fluid damper

The seismic performance assessment of modified steel moment-resisting frame (SMRF) was carried out by nonlinear time-history analysis. The basic bare SMRF was reduced in strength first and then enhanced by installing passive energy dissipating devices (EDDs) to develop modified frame. Passive EDDs comprise both rate-dependent and rate-independent devices. Viscous fluid damper (VFD) is a rate-dependent device whereas buckling-restrained brace is a rate-independent device. The lateral strength of structure was improved by using these devices either alone or in combination. Seven-scaled time-history records were used for incremental dynamic analysis. The stiffness effect on the stories is demonstrated through the lateral displacement profile of the building. The VFD is found to be a good EDD as it significantly improved the performance of the frame at all levels of seismic analysis.     

设置黏滞阻尼墙的钢框架结构振动台试验研究

以3层设置黏滞阻尼墙的钢框架结构为研究对象,对其进行3条地震波在不同水准下的振动台试验。通过对设置与不设置黏滞阻尼墙的两种结构动力特性和动力响应对比,分析了黏滞阻尼墙的减震效果和耗能特征及其变化规律。研究结果表明,黏滞阻尼墙是一种同时提供附加刚度和附加阻尼的被动消能减震装置,其在提供附加阻尼和附加刚度的同时可以对结构位移起到非常显著的控制作用,并且随着输入地震波峰值加速度的增大,该附加刚度逐渐减小,而附加阻尼则逐渐增大。此外,有限元分析结果与振动台试验结果的吻合度随响应对象和激励工况的不同而变化,说明了传统Maxwell模型用于模拟黏滞阻尼墙在动态力学特性方面的局限性。     

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.     

Seismic analysis of benchmark building installed with friction dampers

The 20-storey steel building has been declared as seismically excited benchmark building by structural control community to compare various control strategy, such as active, passive, semi-active and combination thereof. In this study, dynamic behaviour of the benchmark building installed with friction damper is investigated. For evaluation of structural responses, the seismic excitations considered are El Cento, Hachinohe, Northridge and Kobe. The friction damper with numerical rectangular ideal elasto-plastic hysteretic model is proposed to be used for the analysis. The effectiveness of friction dampers for reduction of responses namely, displacement, acceleration, base shear and performance criteria stipulated in the benchmark problem is investigated. Since, the activation of friction damper depends on slip force, a parametric study is also conducted to investigate the optimum slip force of the dampers, which yield the minimum responses. Further, optimal placement of dampers, rather than providing the dampers at all the floor levels is also studied, to minimise the cost of the dampers. Numerical study is also carried out by varying the slip force of dampers along the height of the benchmark building. Results show that for appropriate slip force and optimum location number, friction dampers installed in benchmark building can effectively reduce earthquake-induced responses.     

某站房结构抗震性能分析及采用粘滞阻尼器的减震分析

对某站房结构进行了罕遇地震下的抗震性能分析。屋面和拱支撑的位移较大,屈服杆件集中在屋面,并且夹层结构层间位移超限,不满足抗震设防目标的要求。随后采用粘滞阻尼器进行了减震分析。对替换屋面杆件为阻尼器、在拱上支撑之间设置阻尼器以及两者相组合的方式进行了比较。组合方式的减震效果最优。对25m夹层采用在端部柱间设置阻尼支撑的方式,层间位移减小显著,满足了抗震设防目标的要求。     

Seismic performance of MR frames protected by viscous or hysteretic dampers

This study concerns the behaviour of steel frames protected by different anti‐seismic devices (dampers). Typical hysteretic and viscous dampers are arranged in three steel moment‐resisting frames (MRFs) having different dynamical features but are designed to accomplish determined performance objectives. The proposed devices are selected following an iterative procedure based on the use of a suitable damage functional, which has been applied to control the behaviour of the protected structures under a specific seismic record. The outcomes obtained by implementing incremental dynamic analyses, carried out on the basis of seven historical records characterized by different features, allow to analyse the improvement of the structural performance due to the considered dampers and, therefore, to provide design information about their employment. The comparison of results is carried out taking into account the dampers capacity to protect the structures from damage, the inter‐storey drifts, the residual deformations and the possible amplification effects. In conclusion, the equivalent behaviour factors for each damper type are given, with the aim of providing useful design parameters for the implementation of simplified conventional linear analyses. Copyright © 2014 John Wiley & Sons, Ltd.     

北京A380机库采用粘滞阻尼器的减振控制分析

为研究大跨度网架机库结构的减振控制效果,采用粘滞阻尼器作为减振装置,在三向地震波输入下,对北京A380机库进行减振控制分析。以减小屋盖结构节点竖向位移为减振控制目标,分别在网架结构、抗侧力结构以及网架和抗侧力结构中布置粘滞阻尼器,并进行不同控制方案的比较。结果表明,在网架结构中布置阻尼器时,非线性阻尼器和线性阻尼器的控制效果基本相同,"替换方式"布置阻尼器的控制效果好于"附加方式",替换下弦与中弦之间腹杆的减振效果好于替换中弦与上弦之间的腹杆,在网架四边中部布置阻尼器的控制效果优于在四边均匀布置或布置在无控结构竖向位移最大的节点周围,阻尼器数量宜适中;抗侧力结构中布置阻尼器的控制效果优于布置在网架结构中;网架与抗侧力结构均布置阻尼器,可进一步提高减振控制效果。研究成果可为大跨度网架结构采用粘滞阻尼器减振控制提供参考。     

屈曲约束支撑与黏滞阻尼器的减震效果对比研究

以某钢筋混凝土框架结构工程实例为研究对象,选取与场地条件相匹配的地震动作为激励,在SAP2000程序中计算了该结构在多遇和罕遇地震作用下的非线性动力反应,并在框架结构模型中分别设置屈曲约束支撑和黏滞阻尼器。通过试算确定消能减震装置的参数,使得两种消能减震结构在多遇地震作用下的位移减震率均为40%。在此条件下,对比分析了结构的层间位移角、楼层加速度、基底剪力、柱轴力、塑性铰分布和各层阻尼器的工作状态。分析表明：在多遇地震作用下,屈曲约束支撑增大了结构的加速度响应,而黏滞阻尼器能够减小结构的加速度响应;在罕遇地震作用下,二者均能有效控制楼层的加速度响应,而屈曲约束支撑的位移减震效果更好,但黏滞阻尼器对框架柱内力的减少效果更为显著。     

设置粘滞阻尼墙钢框架结构耗能性能试验研究

设计了三榀不同类型的钢框架结构模型,通过对模型的快速水平周期加载试验,进行了设置粘滞阻尼墙钢框架结构减振性能的比较和分析。对设置阻尼墙后钢框架结构的破坏形态、滞回特性、骨架曲线、阻尼力、抗剪刚度、耗能性能、等效阻尼比等进行了研究,对阻尼墙不同布置方式对上述各项性能的影响进行了分析,并对上述各项性能与加载频率、位移幅值的变化关系进行了探讨。结果表明,设置阻尼墙后,钢框架结构的耗能能力和阻尼均有显著提高,结构的抗剪刚度增加,结构的地震响应显著减小。设置阻尼墙钢框架结构的滞回特性与频率、位移幅值相关。阻尼墙不同布置方式对结构滞回特性的影响不明显。     

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。     

对液体粘滞阻尼器动力性能及测试要求的研究及探讨

液体粘滞阻尼器作为有效和重要的消能减振产品目前在我国已经得到越来越广泛的应用,但对这类阻尼器的性能要求、质量控制及动力测试所做的研究及探讨所见不多。给出了液体粘滞阻尼器的不同类型及作用机理,介绍了粘滞阻尼器在美国的发展进程及状况。举例说明了美国对液体粘滞阻尼器的测试要求,即产品预检验、原型测试及质量验收测试。对部分测试内容进行了着重讨论,并列出了美国大型动力测试设备的情况。     

斜港大桥减隔震设计

苏州斜港大桥新建工程为主跨180 m三跨双层拱梁组合桥,全钢结构.目前该桥型国内不多见.针对大桥的地震响应分析及减隔震设计作了详细论述,给出了该桥的抗震设计思路和减隔震设计措施.分别采用了反应谱和非线性时程分析方法对桥梁结构进行了计算分析,经过对多种工况的计算分析比较,最终采用粘滞阻尼器来减小结构的地震响应.     

近场脉冲型地震作用下黏滞阻尼器对双柱#br# 摇摆桥墩减震作用研究

为研究黏滞阻尼器对双柱摇摆桥墩在近场脉冲型地震作用下的减震作用,基于摇摆刚体假定和拉格朗日方程,对采用黏滞阻尼器的双柱摇摆桥墩进行实例分析、参数分析和抗倒塌能力分析。研究结果表明：黏滞阻尼器可减小双柱摇摆桥墩的地震位移反应,且作为速度型阻尼器,其在近场脉冲型地震作用下的减震效果比远场地震更为显著;在近场脉冲型地震作用下,随着黏滞阻尼器的无量纲阻尼常数(λ)的增大和阻尼指数(n_v)的减小,桥墩位移反应随之变小,当阻尼器失效位移大于120mm时桥墩峰值位移反应无显著变化;黏滞阻尼器的减震作用可有效提高双柱摇摆桥墩在近场脉冲型地震作用下的抗倒塌能力,λ越大和n_v越小,桥墩的抗倒塌能力越强。