结构附加粘滞阻尼器的抗震设计

本文结合抗震设计规范反应谱,给出了一个附加非线性流体粘滞阻尼器结构的抗震设计方法。研究了非线性阻尼器的力学特性,引入了非线性流体阻尼器的等效线性阻尼比,给出了计算最大加速度时刻附加非线性流体阻尼器结构反应的荷载组合系数,提出了按阻尼力的水平力分量与楼层剪力成正比的原则分配阻尼器阻尼系数的方法。同时给出了基于抗震规范设计反应谱附加非线性阻尼器结构的设计流程,通过一个算例说明了使用该方法设计附加非线性粘滞阻尼器结构的全过程。算例分析表明,这种设计方法适合于手算,便于设计人员掌握,在初步设计阶段可以快速、有效地设计满足给定性能水平的附加非线性流体阻尼器体系。     

A two‐step direct method for estimating the seismic response of nonlinear structures equipped with nonlinear viscous dampers

The insertion of fluid viscous dampers in building structures is an innovative technology that can improve significantly the seismic response. These devices could be very useful also in the retrofit of existing buildings. The effect of this typology of damping system is usually identified with an equivalent supplemental damping ratio, which depends on the maximum displacement of the structure, so that iterative procedures are required. In this paper, a simplified direct assessment method for nonlinear structures equipped with nonlinear fluid viscous dampers is proposed. The method proposed in this study is composed by two steps. The first one yields the direct estimate of the supplemental damping ratio provided by nonlinear viscous dampers in presence of a linear elastic structural response. The second step extends the procedure to structures with nonlinear behavior. Both graphical and analytical approaches have been developed. The proposed method has then been verified through several applications and comparisons with nonlinear dynamic analyses. Moreover, an investigation has been performed with regard to the influence of the relations that define the damping reduction factor and the hysteretic damping. Copyright © 2014 John Wiley & Sons, Ltd.     

Asymmetric one‐storey elastic systems with non‐linear viscous and viscoelastic dampers: Simplified analysis and supplemental damping system design

Investigated is the accuracy in estimating the response of asymmetric one‐storey systems with non‐linear viscoelastic (VE) dampers by analysing the corresponding linear viscous system wherein all non‐linear VE dampers are replaced by their energy‐equivalent linear viscous dampers. The response of the corresponding linear viscous system is determined by response history analysis (RHA) and by response spectrum analysis (RSA) extended for non‐classically damped systems. The flexible and stiff edge deformations and plan rotation of the corresponding linear viscous system determined by the extended RSA procedure is shown to be sufficiently accurate for design applications with errors generally between 10 and 20%. Although similar accuracy is also shown for the ‘pseudo‐velocity’ of non‐linear VE dampers, the peak force of the non‐linear VE damper cannot be estimated directly from the peak damper force of the corresponding linear viscous system. A simple correction for damper force is proposed and shown to be accurate (with errors not exceeding 15%). For practical applications, an iterative linear analysis procedure is developed for determining the amplitude‐ and frequency‐dependent supplemental damping properties of the corresponding linear viscous system and for estimating the response of asymmetric one‐storey systems with non‐linear VE dampers from the earthquake design (or response) spectrum. Finally, a procedure is developed for designing non‐linear supplemental damping systems that satisfy given design criteria for a given design spectrum. Copyright © 2003 John Wiley & Sons, Ltd.     

城市桥梁粘滞阻尼器防地震碰撞分析与参数设计

研究了粘滞阻尼器防止城市梁桥地震碰撞反应的效果并提出了其参数设计方法。分析了线性粘滞阻尼器与非线性粘滞阻尼器阻尼系数的等效关系。运用随机振动理论与随机等效线性化理论建立了邻联间安装粘滞阻尼器后最大相对位移及墩顶最大位移的计算方法。以控制邻联最大相对位移小于实际间隙为目标,提出了防碰撞粘滞阻尼器参数设计方法。对1座4跨隔震连续梁桥进行了仿真分析,结果表明:粘滞阻尼器能有效抑制邻联的碰撞反应且不会显著增大桥墩的延性需求。在相同阻尼系数的情况下,粘滞阻尼器的速度指数越小,其防碰撞效果越好。利用人工波进行的时程分析结果验证了参数设计方法的可行性。     

台湾某钢框架大楼采用阻尼器补强结构减震效果评析

阻尼器是一种效果良好的减震装置,将阻尼器安装于结构中能够适时为结构体系提供阻尼力,从而减小地震作用对结构的破坏。黏滞阻尼器对振动的反应比较敏感,在结构受到较小振动时就可以发挥其减震效果,其阻尼力会随着振动周期和使用状态温度的不同而变化。当地震发生时,安装在结构中的阻尼器会消减地震作用,降低传导到主结构体系的地震能量,减小结构相对位移。本文介绍了黏滞阻尼器的工作原理和安装有黏滞阻尼器的结构体系的阻尼比的计算方法,对减震结构的减震效果的评析方法做出探讨,并以一安装有黏滞阻尼器的台湾某既有钢框架结构为例,分析了(1)该结构在遭受地震作用时的地震反应;(2)该结构体系在不同地震作用水平时的阻尼比,包括主体结构阻尼比和黏滞阻尼器阻尼比;(3)结构安装黏滞阻尼器后的减震效果。实例对本文的减震评析方法和减震效果进行了说明和分析,计算及分析结果表明利用黏滞阻尼器加固既有结构能够取得较好的减震效果,本文所提减震效果评析方法是一种实用有效的评析方法,对类似工程的减震评析具有一定的参考价值。     

Stiffness‐damping simultaneous identification using limited earthquake records

A new method of stiffness‐damping simultaneous identification of building structures is proposed using limited earthquake records. It is shown that when horizontal accelerations are recorded at the floors just above and below a specific storey in a shear building model, the storey stiffness and the damping ratio can be identified uniquely. The viscous damping coefficient and the linear hysteretic damping ratio can also be identified simultaneously in a numerical model structure. The accuracy of the present identification method is investigated through the actual limited earthquake records in a base‐isolated building. It is further shown that an advanced identification technique for mechanical properties of a Maxwell‐type model can be developed by combining the present method with a perturbation technique. Copyright © 2000 John Wiley & Sons, Ltd.     

Asymmetric one‐storey elastic systems with non‐linear viscous and viscoelastic dampers: Earthquake response

Investigated are earthquake responses of one‐way symmetric‐plan, one‐storey systems with non‐linear fluid viscous dampers (FVDs) attached in series to a linear brace (i.e. Chevron or inverted V‐shape braces).Thus, the non‐linear damper is viscous when the brace is considered rigid or viscoelastic (VE) when the brace is flexible. The energy dissipation capacity of a non‐linear FVD is characterized by an amplitude‐dependent damping ratio for an energy‐equivalent linear FVD, which is determined assuming the damper undergoes harmonic motion. Although this formulation is shown to be advantageous for single‐degree‐of‐freedom (SDF) systems, it is difficult to extend its application to multi‐degree‐of‐freedom (MDF) systems for two reasons: (1) the assumption that dampers undergo harmonic motion in parameterizing the non‐linear damper is not valid for its earthquake‐induced motion of an MDF system; and (2) ensuring simultaneous convergence of all unknown amplitudes of dampers is difficult in an iterative solution of the non‐linear system. To date, these limitations have precluded the parametric study of the dynamics of MDF systems with non‐linear viscous or VE dampers. However, they are overcome in this investigation using concepts of modal analysis because the system is weakly non‐linear due to supplemental damping. It is found that structural response is only weakly affected by damper non‐linearity and is increased by a small amount due to bracing flexibility. Thus, the effectiveness of supplemental damping in reducing structural responses and its dependence on the planwise distribution of non‐linear VE dampers were found to be similar to that of linear FVDs documented elsewhere. As expected, non‐linear viscous and VE dampers achieve essentially the same reduction in response but with much smaller damper force compared to linear dampers. Finally, the findings in this investigation indicate that the earthquake response of the asymmetric systems with non‐linear viscous or VE dampers can be estimated with sufficient accuracy for design applications by analysing the same asymmetric systems with all non‐linear dampers replaced by energy‐equivalent linear viscous dampers. Copyright © 2003 John Wiley & Sons, Ltd.     

基于楼层剪力的等效阻尼比计算方法研究

针对现有附加有效阻尼比计算方法存在的问题,本文从能量的角度揭示了阻尼比对结构影响的机理。从结构设计的角度,提出一种在时程分析下基于楼层剪力的消能减震结构等效阻尼比计算方法。对布置黏滞阻尼器和软钢阻尼器的消能减震模型,采用本文提出的等效阻尼比计算方法,建立等效结构进行结构响应对比。结果表明,由该计算方法得到的等效阻尼比能够准确地评估阻尼器在结构中的耗能效果,建立的等效结构能够准确反映消能减震结构实际情况。基于楼层剪力的等效阻尼比计算方法通过等效结构楼层剪力大于或等于消能减震结构楼层剪力判断迭代完成,该方法计算过程不涉及阻尼器参数及结构形式,适用于所有阻尼器类型与结构类型。计算得到的等效结构进行设计能够确保结构设计的安全。     

相邻结构连接阻尼器的最优设计参数

本文通过Maxwell模型模拟的黏滞阻尼器连接的2种不同相邻结构的地震反应分析,对阻尼器设置的位置和阻尼参数进行了同时优化。在El Centro波、Tianjin波和Taft波3种较典型的地震动作用下,分别对不同质量比和不同刚度比的主、子结构在无阻尼和有阻尼情况下进行了地震反应分析,并以主结构的顶层最大相对位移最小作为优化目标,寻求出最优的阻尼器摆放位置以及对应的最优阻尼系数。结果显示,当阻尼器选择合适的安放位置和合理的阻尼参数时,主、子结构的地震反应都会有一定程度的降低,从而收到较好的减震效果。     

An alternative practical design method for structures with viscoelastic dampers

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.     

Active viscous damping system for control of MDOF structures

The development and applications of a supplemental viscous damping device with active capacity are described. The system of the dampers defined as active viscous damping system (AVDS) is presented herein. Structural control principles defined here as active control theory (ACT) are used to obtain the control forces at each time step during an excitation. Control of the damping forces is possible due to a mechanical structure of the proposed AVDS and do not require the input of large power and energy. This system can be efficiently used to enhance the damping of a structure without adding in stiffness and strength. The added damping forces can be adjusted in a wide range. Its efficiency is demonstrated by a numerical simulation of a seven‐storey building subjected to earthquakes. The simulation shows that the behaviour of the damped structure with the AVDS is significantly improved compared to that of an uncontrolled system. Moreover, the response is better than that of adding either passive viscous dampers or electrorheological damping devices. Copyright © 2001 John Wiley & Sons, Ltd.     

Performance spectra based method for the seismic design of structures equipped with passive supplemental damping systems

A new direct performance‐based design method utilizing design tools called performance‐spectra (P‐Spectra) for low‐rise to medium‐rise frame structures incorporating supplemental damping devices is presented. P‐Spectra are graphic tools that relate the responses of nonlinear SDOF systems with supplemental dampers to various damping parameters and dynamic system properties that structural designers can control. These tools integrate multiple response quantities that are important to the performance of a structure into a single compact graphical format to facilitate direct comparison of different potential solutions that satisfy a set of predetermined performance objectives under various levels of seismic hazard. An SDOF to MDOF transformation procedure that defines the required supplemental damping properties for the MDOF structure to achieve the response defined by the target SDOF system is also presented for hysteretic, linear viscous and viscoelastic damping devices. Using nonlinear time‐history analyses of idealized shear structures, the accuracy of the transformation procedure is verified. A seismic performance upgrade design example is presented to demonstrate the usefulness of the proposed method for achieving design performance goals using supplemental damping devices. Copyright © 2012 John Wiley & Sons, Ltd.     

Effects of brace stiffness on performance of structures with supplemental Maxwell model‐based brace–damper systems

Shear‐type buildings with Maxwell model‐based brace–damper systems are studied in this paper with a primary emphasis on the effects of brace stiffness. A single‐story building with a viscous damper installed on top of a Chevron‐brace is first investigated. Closed‐form solutions are derived for the simple structure, relating the brace stiffness and damper coefficient to the targeted reduction in response displacement or acceleration. For a given brace stiffness, the solution is minimized to give a set of formulae that will allow the optimal damper coefficient to be determined, assuring the desired performance. The model is subsequently extended to multistory buildings with viscous dampers installed on top of Chevron‐braces. For a targeted reduction in the mean square of the interstory drift, floor acceleration or base shear force, the minimum brace stiffness and optimal damper coefficients are obtained through an iterative procedure. The response reduction, which signifies the improved performance, is achieved by a combination of brace stiffness and viscous damper coefficients, unlike conventional approaches where damper coefficients are typically optimized independent of brace stiffnesses. Characteristics of multi‐degree‐of‐freedom systems are studied using a 2‐story and a 10‐story buildings where the effects of brace stiffness on the overall performance of the building can be quantified. Copyright © 2010 John Wiley & Sons, Ltd.     

基于负刚度装置的超长联大跨连续梁桥地震反应控制研究

为完善超长联大跨连续梁桥的减、隔震技术,将负刚度装置引入到超长联大跨隔震连续梁桥中组成新型减、隔震系统,并与黏滞阻尼器-摩擦摆支座组合减震系统进行比较。基于CSiBridge软件建立全桥有限元模型,负刚度装置采用弹性多段线模拟,摩擦摆支座采用双线性恢复力模型,黏滞阻尼器采用Maxwell模型,输入3条地震波进行非线性时程分析,考查两种新型减、隔震系统下桥梁结构的地震反应,探究负刚度系统及黏滞阻尼器系统对超长联大跨连续梁桥地震反应的控制效果。研究结果表明：负刚度装置与黏滞阻尼器均可以有效地减小超长联大跨隔震连续梁桥的支座位移。负刚度装置对桥墩内力反应及梁体加速度反应的控制优于黏滞阻尼器。负刚度装置在超长联大跨连续梁桥地震反应控制中有较好的应用前景。     

基于位移的RC框架结构与附加消能减震装置一体化设计

消能减震结构中主体结构和附加消能减震装置通常是单独设计的,由于主体结构和附加消能减震装置之间的耦合特性,为实现期望的性能目标需要进行迭代计算。本文提出一种基于位移的主体结构与附加消能减震装置一体化设计方法,首先,基于所选地震动记录和预期性能目标,得出结构阻尼比需求曲面;其次,推导了阻尼器-支撑部件参数计算公式,在已知主体结构基本信息及预期性能目标时,根据阻尼比需求曲面及所提出公式即可获得所需附加消能减震装置的支撑刚度及粘滞系数;再次,引入无量纲成本指数,以成本指数最小为目标函数,在可实现目标性能的附加消能减震装置参数中识别最优设计参数;最后,基于所提出的设计方法,分别以等效SDOF体系、MDOF体系及SAP2000设计的6层RC框架结构为例,对所提出的设计方法的有效性进行了验证,结果表明:经一体化设计的结构体系均可实现性能目标。     

Choice between series and parallel connections of hysteretic system and viscous damper for seismic protection of structures

Supplemental viscous damping devices are generally envisioned to be connected in parallel to the inelastic parent structure or hysteretic damping devices. This gives rise to higher base shear, and often greater ductility demand of the hysteretic system. The series connection of the viscous and hysteretic system (the inelastic structure or a damper) is an alternative approach. In this paper, comparisons between the series and parallel connections of the hysteretic system and viscous dampers are done through response spectra analyses of single degree of freedom structures. Ductility demand of the hysteretic system and the total base shear are chosen as the response quantities. For the series model, a semi‐implicit solution scheme for classical Maxwell model is modified to include the inelasticity of the time‐independent hysteretic spring. It is observed that the series connection of the 2 dampers gives lower base shear than does the parallel connection. For long‐period and low‐damping structures, the ductility demand of the hysteretic system in series connection is higher than that in parallel connection. Increasing the viscous damping in series connection reduces the ductility demand substantially, lower than that obtained in parallel connection. Practical methods for implementing the series and parallel connections, in line with roof isolation, are also suggested.     

钢梁阻尼器的最佳延性率及其控制

基于双线性和三线性的力－位移滞回线假设，导出了钢梁阻尼器隔震系统等效阻尼比与阻尼器延性率的关系；为了获得大阻尼比隔震系统，以尽量减小隔震系统的地震反应，求得了使系统阻尼比为最大的阻尼器相应延性率（即最佳延性率）所需满足的条件；给出了在给定地震地面运动输入条件下，使系统阻尼器变形位移达到最佳延性率的阻尼器初始刚度和屈服位移的确定方法。     

剪力墙的等效周期和等效阻尼比研究

结构弹塑性反应可用等效线性化方法中的等效刚度和等效阻尼比进行计算。为研究钢筋混凝土剪力墙的等效刚度和等效阻尼比,通过分析剪力墙的力-位移简化四折线滞回模型,推导了其屈服点和峰值点的等效刚度、等效周期和等效阻尼比的计算公式。为验证其准确性和适用性,采用提出的峰值点等效刚度、等效阻尼比公式和FEMA 440建议的公式,分别计算了42片钢筋混凝土剪力墙试件的等效刚度和等效阻尼比,并进行了对比分析。结果表明:提出的计算公式和FEMA 440建议的公式所得到的等效周期和等效阻尼比值与试验值比较吻合,因此,所提出的计算剪力墙的等效周期和等效阻尼比的公式较为合理。     

磁流变耗能器及其性能

磁流变换（ＭＲ）是一种智能材料,它能够在强磁场的作用下从牛顿流体变化为粘塑流体,用磁流变液制作的耗能装置简单,体积小,能耗小,可连续可逆变化,是实现半主动控制的理想控制元件,本文介绍了磁流变液的材料特征,建立了磁流变耗能器的恢复力简化模型,根据磁流变液耗器的特点,提出了制作磁流变耗器时参数设计的基本要求;最后,利用等效线性化方法,提出了磁流变耗能器总阻尼系数的计算方法,并且比较了其中的粘性阻尼系数