Dynamic characteristics and viscous dampers design for pile‐soil‐structure system

A series of large‐scale shaking table tests are conducted on tall buildings with and without energy dissipation devices on soft soils in pile group foundations, representing pile‐soil‐structure interaction (PSSI) system and the corresponding fixed‐base situations. The superstructure is a 12‐story reinforced concrete (RC) frame. The dynamic characteristics of the test models show that the frequencies decrease and the damping ratio increase in PSSI system by comparison with the fixed‐base structures. The mode shapes of PSSI system are different from that under fixed‐base condition, and the mode shapes of structure without dampers change greater than that with energy dissipation devices under various white noises. An improved method for structural dynamic characteristics, considering the impedance function of piles, is developed to address the issue of modal parameters with PSSI effect. In addition, the structural dynamic parameters of the large‐scale shaking table tests are identified using the modification method and other regulation methods, demonstrating that the improved approach is highly accurate and effective. Subsequently, a design procedure for viscous dampers of structures with PSSI effect is presented based on the dynamic characteristics of the system. Finally, the dynamic responses of the structure with viscous dampers in the practical engineering are decreased effectively, indicating the good performance of designed viscous dampers. The numerical results also show that the damping efficiency of interstory drift is larger than the acceleration and interstory shear force. Therefore, the improved modal parameters method, validated through a series large‐scale shaking table tests, is applicable for identifying dynamic characteristics of pile‐soil‐structure with energy dissipation devices system. The design procedure of viscous dampers, proved by a reinforced concrete frame structure located on a practical Shanghai soft site, can be employed to design the viscous dampers considering seismic PSSI effect.     

粘弹性消能减振结构体系设计参数研究

对工程结构采用粘弹性阻尼器消能减振的设计参数进行了研究。首先,分析了支撑中连接钢杆刚度对粘弹性阻尼器消能效果的影响,定义并导出了粘弹性消能支撑的损耗因子表达式,同时给出了参数合理的取值范围;另外,探讨了粘弹性消能结构阻尼比的计算,提出了消能支撑设计的简化方法;最后,给出了安装粘弹性消能支撑后结构地震影响系数的修正计算公式。     

某裙房结构大跨度空间改造与减震设计

以某酒店裙房框架结构大跨度空间改造为研究对象,为保证大跨度空间改造后满足结构抗震要求,采用黏滞阻尼器和防屈曲支撑的混合减震控制方案对该裙房框架结构进行减震控制研究,分析了减震框架结构的动力响应和阻尼装置的耗能性能。研究结果表明:混合减震控制方法能有效提高裙房大跨度空间结构的抗震性能,多遇和罕遇地震作用下的减震效果分别达到27.51%和46.52%;黏滞阻尼器在多遇和罕遇地震作用下均发挥了良好的耗能性能;防屈曲支撑在多遇地震作用下作为钢支撑为结构提供刚度,但在罕遇地震作用下亦发挥了良好的耗能性能,表明所提减震控制方案可对结构同时附加刚度和阻尼。本文研究成果可为类似结构大跨度空间改造提供参考。     

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。     

偏心结构消能减震技术的分析研究

由于偏心结构质量中心与刚度中心不重合,在地震作用下会产生扭转振动,对结构整体抗震性能十分不利。工程设计通常在远离刚度中心的抗侧结构中,采取设置支撑等增加刚度的措施,减小结构的偏心程度。本文采用消能减震技术,在偏心响应较大的抗侧结构中设置消能减震阻尼器,来减小偏心结构的扭转地震响应。论文通过弹塑性时程分析方法,研究了偏心结构、设置普通支撑、设置速度型阻尼器和位移型阻尼器四种结构方案在常遇、设防和罕遇地震作用下的扭转响应,研究了消能减震技术对偏心结构的减震控制效果。分析结果表明,消能减震技术可以有效控制偏心结构的扭转响应,在大震条件下较好的控制主体结构构件的受力。最后本文针对王府井大厦偏心结构工程进行了阻尼消能减震结构的设计。     

加强层结构和消能减震结构地震反应对比分析

以某超高层建筑为例,对比分析了加强层结构和带粘滞阻尼器的消能减震结构的地震时程反应,结果表明:消能减震结构的位移反应明显小于加强层结构,在地震作用下,消能减震结构能有效地减小结构的基底剪力,粘滞阻尼器消耗了大量输入到结构中的能量,有效地保护了主体结构.     

消能减震支撑体系研究与在高烈度区的工程应用

对高烈度地震区某6层混凝土框架结构办公楼应用由钢支撑和液体粘滞阻尼器组成的消能减震阻尼器支撑体系进行了抗震分析。利用ETABS软件对其在设防烈度8度(0.3g)的地震作用下的地震反应进行了非线性时程分析。计算分析表明,该类消能减震阻尼器支撑有良好的消能减震效果,为类似工程提供了较好的参考。     

地震动作用下消能构件的动力可靠性分析

对地震动作用下消能构件（油阻尼器）的动力可靠性分析,建议了一种简化的动力可靠度分析方法。首先基于首次超越破坏准则,采用极值分布描述建立了消能构件动力可靠度的等价功能函数表达,定义了消能构件响应的安全裕量|然后采用点估计法计算安全裕量的统计矩,并结合四阶矩方法求解消能构件的动力可靠度,最后,以受到地震动作用的一栋钢结构行政楼的油阻尼器动力可靠度问题为例,采用建议方法分析了油阻尼器撞击失效的动力可靠性问题,计算结果表明了建议方法的可行性和适用性。     

布置黏滞阻尼器的框架结构抗震性能分析

提出附设黏滞阻尼器的结构设计流程,以昆明某幼儿园工程为例,通过在结构上附设黏滞阻尼器,对比原结构和消能减震结构在地震作用下的最大层间位移角和最大层间位移,研究了高地震烈度区框架结构附设非线性黏滞阻尼器后的减震效果。结果表明:黏滞阻尼器对结构减震效果明显,合理布置黏滞阻尼器后,框架结构的抗震性能满足规范要求。研究为高地震烈度区附设黏滞阻尼器的框架结构抗震设计提供了参考。     

黏弹性阻尼器在结构抗震控制中的应用

首先介绍了传统抗震理论和结构震动理论以及黏弹性阻尼器在结构的耗能减震中的应用。之后对黏弹性阻尼器的力学模型进行分析介绍,指出积分型本构关系的黏弹性阻尼器在应用中有更大灵活性。最后通过计算机模拟计算出有黏弹性阻尼器的建筑结构受到地震激励时的瞬态和稳态位移概率分布,说明黏弹性阻尼器对于地震时结构的瞬态位移响应和稳态位移响应均具有良好的减震效果,并且不同材料的黏弹性阻尼器对于在地震作用下建筑结构的瞬态或稳态位移响应有不同的减振效果。     

A Unified Analysis Model for Energy Dissipation Devices Used in Seismic Structures

Abstract:   To date, various types of energy dissipation devices (EDDs) have been invented and applied to structural systems for mitigating their seismic responses. An elastic structure with EDDs can be treated as a nonlinear dynamic system with hysteretic property. Due to the diversity of the hysteretic properties of various EDDs, it is difficult to obtain a generic analysis method that can be applied to structures with different EDDs. In this study, a unified analysis model containing an internal variable is proposed for simulating the hysteretic behavior of various types of EDDs. By assigning different physical meanings to the internal variable, the model is able to simulate three types of widely used EDDs, namely, yielding, viscoelastic, and friction dampers. The unified model is also able to simulate nonlinear viscous dampers whose velocity terms have an exponential coefficient not equal to 1.0. Furthermore, based on this model, this article also developes a numerical analysis method derived from the discrete-time solution of a state-space equation. Without requiring iteration at each computational time step, the numerical method is able to accurately simulate the hysteretic properties of the three kinds of EDDs. The accuracy and efficiency of the proposed analysis method is investigated by using the analytical solution of a nonlinear system governed by Duffing's equation, and also by using a seismic structure equipped with multiple EDDs.     

消能减震结构的试算设计方法

在结构中如何确定阻尼器位置及相关参数是消能减震结构设计的关键问题.本文在仔细分析阻尼器参数特性的基础上,结合"择层设计"思想,提出了一种设置阻尼器消能减震的试算设计方法.如对于粘滞阻尼器,采用该方法可以快速确定阻尼器的位置、个数、粘滞阻尼系数和速度指数.计算实例表明,该方法简便有效,容易掌握.     

西安石油宾馆采用粘弹性支撑减震设计与研究

对8度区的西安石油宾馆采用粘弹性消能支撑进行减震设计与研究。首先利用时程分析计算原结构在多遇地震作用下的变形,针对原结构不满足抗震要求,采用粘弹性支撑对原结构进行抗震加固;随后阐述了粘弹性阻尼器及消能支撑的设计,简述了阻尼器位置的优化。通过对该宾馆加与不加粘弹性支撑的时程分析,计算结果表明,粘弹性阻尼器可有效降低结构的振动反应,是一种性能良好的消能减震装置。     

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。     

A proposed structural design method considering fluid viscous damper degradations

The purpose of this study is to perform a seismic assessment of the moment resistant steel structures enhanced with viscous dampers where the dampers are degraded due to possible leak of viscous fluid. This paper proposes a design procedure based on corrected response spectrums as a result of seismic assessments based on nonlinear time series analyses on three‐, five‐, and seven‐story steel frame structures denoted as “generic structures.” The proposed design procedure is a seismic displacement‐based design methodology for buildings with viscous dampers as passive energy dissipation systems. Prior literature on these types of structures often overlook the viscous dampers degradation due to the fluid leak. In this paper, in order to study these effects, a target displacement is specified at first and the lateral forces and required stiffness are obtained. The effectiveness of the proposed procedure is verified with the collapse fragility curves of the generic structures according to the ASCE 7‐10 and displacement‐based design methodology. The results show that the structures designed based on proposed procedure demonstrate acceptable performance with degrading dampers.     

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.     

粘滞流体阻尼器用于建筑结构的减震设计原理与方法

研究了粘滞流体阻尼器用于建筑结构消能减震设计的原理、分析方法。包括阻尼器的设置、消能支撑的型式、支撑钢杆的设计、抗震设防目标、消能减震建筑结构的特点。给出了消能减震结构的附加水平控制力、附加有效阻尼比、地震影响系数、阻尼矩阵的计算方法;介绍了振型分解反应谱法和直接动力时程分析法的设计计算要点。最后给出了采用粘滞流体阻尼器进行消能减震设计的实用设计步骤。     

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...     

黏滞阻尼器在钢结构加层改造中抗震性能研究

在加层钢框架结构中的中心支撑上设置消能减震装置——黏滞性阻尼器,用来调整加层结构整体阻尼比、消耗地震能量．分析表明：消能减震体系主要是减小加层钢框架过大侧向层间位移,解决钢结构直接加层产生的鞭梢反应,降低层剪力与柱轴力,控制层间位移角出现的位置与时间,从而对加层结构振动反应进行有效抑制,使结构整体满足抗震规范的要求．     

新建减震结构优化设计方法

基于隔震理论提出减震结构优化设计方法,对某8度区11层框架结构进行了减震设计,通过附加粘滞阻尼器达到设防目标,根据振型分析调整隔震层层高,使安装阻尼器楼层位置降低至底部2层;将选取的7组加速度时程曲线分为4种工况,采用ETABS对减震结构进行了多遇地震作用下的时程分析,比较了各工况下阻尼器耗能总量和最大层间位移角。研究结果表明:将主体结构与减震装置看作有机整体对减震结构进行设计可取得较好的减震效果;将隔震层主体结构抗侧刚度作为减震装置设计参数,使隔震层基本周期与场地特征周期相等可取得最佳减震效果。