考虑支撑变形时安装非线性粘滞消能器结构的抗震设计方法

通过理论分析和大量数值模拟,揭示了线性和非线性粘滞消能器两端的相对水平位移幅值与所在层的层间位移幅值之间的关系,总结提出了考虑支撑变形时安装非线性粘滞消能器结构的实用抗震设计步骤。上述研究结果拓展了现行《建筑抗震设计规范》中有关粘滞消能器部分的设计规定。     

直接基于位移可靠度的抗震设计方法中目标位移代表值的确定

针对20多个现役结构，以基于力的抗震设计方法所求基底剪力与直接基于位移的抗震设计方法所求基底剪力相等为原则，回归给出了直接基于位移的抗震设计中基底剪力的调整系数。在此基础上，通过进一步分析，提出了直接基于位移可靠度的抗震设计中层间目标位移代表值的确定方法。最后，总结给出了直接基于位移可靠度的抗震设计步骤。     

一种直接基于位移的结构抗震设计方法

利用我国现行抗震规范,直接根据结构的底层层间目标位移反向求取结构的底层层间屈服剪力;给出了该屈服剪力与结构基底剪力之比的数学表达式,初步分析了影响该比值的主要因素及其影响规律。在此基础上,提出了一种新的直接基于位移的结构抗震设计方法。最后,通过算例分析初步考察了该方法的可行性。     

直接基于位移的结构抗震设计理论研究进展

直接基于位移的抗震设计是实现基于性能抗震设计思想的一条有效途径,其理论主要包括三方面的内容,即直接基于位移的抗震设计方法、位移需求估计方法和目标位移的确定。本文在阅读了大量文献的基础上,对国内外在这三方面的研究进行了介绍,并对今后的研究方向进行了展望。     

直接基于位移的抗震设计方法的研究

系统介绍了直接基于位移的抗震设计方法,通过比较直接基于位移的设计方法与我国现行规范采用的基于力的设计方法的差别,指出直接基于位移的抗震设计方法能在预计的结构形态和计算的结构反应之间建立关系,是一种有广泛发展前景的抗震设计方法。     

设置局部粘滞消能支撑的框架节点抗震试验研究

提出了具有位移放大效应的局部粘滞消能支撑的构成及工作原理,开展了设置该类支撑的钢筋混凝土梁-柱节点的反复加载试验,初步考察了节点的抗震性能,并通过对比试验与常规钢筋混凝土梁-柱节点进行了比较。研究结果表明,安装该类支撑后节点的耗能能力明显提高,梁端位移幅值较大时提高幅度可达200%以上,大大改善了节点的抗震性能。     

消能支撑框架结构设计方法探讨

本文提出了一种新的消能支撑框架结构设计方法，该方法能够实现罕遇地震下结构的目标位移控制，其主要设计思路是框架主体结构按非抗震设计或降低烈度进行抗震设计，消能支撑则由罕遇烈度地震下满足给定层间位移角限值的优化计算来确定。本文还给出了一个15层框架结构的设计算例，并把本文方法的设计结果与按常规方法的设计结果进行了比较。     

钢筋混凝土框架结构直接基于位移的抗震设计

直接基于位移的抗震设计方法是对基于力的抗震设计方法的重大改进。按此方法进行设计时,需要解决的关键问题是确定结构的目标位移和相应的侧移模式。提出用框架梁节点截面屈服时的位移作为目标位移,并推导了层间屈服位移的计算公式;然后用结构近似的第一振型曲线作勾其侧移模式,对层间屈服位移进行修正。算例表明,本方法计算结果合理。     

扇形铅黏弹性消能器设计参数对加固框架抗震性能影响分析

为研究扇形铅黏弹性消能器设计参数对加固框架抗震性能的影响,使用ABAQUS软件建立加固框架试件的精细化有限元模型,并基于试验结果验证其合理性,在此基础上,研究了扇形有效半径、黏弹性层宽度、铅芯直径3个关键设计参数对扇形铅黏弹性消能器加固框架结构抗震性能的影响及规律。分析结果表明,增加扇形铅黏弹性消能器的扇形有效半径、黏弹性层宽度、铅芯直径均可以提高加固框架的初始刚度、屈服荷载和峰值荷载;增加消能器的扇形有效半径可以显著提高加固框架的抗震性能;为避免消能器扇形有效半径过大导致梁柱局部应力集中,在既有结构加固中,扇形铅黏弹性消能器应避免选取过大的扇形有效半径;消能器的铅芯大小对加固框架的后期承载力影响不大。     

改进直接基于位移的钢筋混凝土框架结构抗震设计研究

直接基于位移法进行抗震设计时,最初结构的刚度和承载力均是未知的,设计中需假定预期设计结构的振型模式和由此得到的结构侧向地震力分布,这样的设计结果会产生一定的偏差.针对此问题,提出了改进直接基于位移的抗震设计方法,即首先初步设计结构,根据初设结构的振型模式等效单自由度体系,结合目标位移反向设计结构刚度,将设计结构的刚度与初设结构刚度比较,进行调整设计,最后进行承载力设计.程序中为减少迭代次数,定义了结构竖向刚度调整系数,用以简化结构弹性刚度的确定过程,从而实现设计结构在相应地震设防水准下满足预期位移的控制要求.最后通过算例证明了该方法具有一定的准确性.     

Direct design method based on seismic capacity redundancy for structures with metal yielding dampers

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.     

基于性能的黏弹性阻尼器减震结构抗震设计

根据黏弹性阻尼器的特点和抗震规范的要求,分别提出了用于黏弹性阻尼器减震结构抗震分析的弹性及弹塑性需求谱,前者是基于黏弹性阻尼器减震结构等效阻尼比的简化计算公式及规范规定的反应谱;后者是基于修正的V id icRμ-μ-T关系。在此基础上,借助模态推覆分析,提出了可以考虑高阶振型影响的黏弹性阻尼器消能减震结构体系的能力谱分析方法,并对一8层钢筋混凝土消能减震框架结构进行了"中震不坏,大震可修"性能水准下的抗震分析。算例结果表明,采用该方法分析黏弹性阻尼器减震结构体系是可行的、有效的。     

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.     

Optimum placement and characteristics of velocity-dependent dampers under seismic excitation

In this study,through novel drift-based equations of motion in the frequency domain,optimum placement and characteristics of linear velocity-dependent dampers are investigated.In this study,the sum of the square of the absolute values of transfer matrix elements for interstory drifts is considered as the optimization index.Optimum placement and characteristics of dampers are simultaneously obtained by minimizing the optimization index through an incremental procedure.In each step of the procedure,a predefined value is considered as the damper characteristic.The optimum story for this increment is selected such that it leads to a minimum value for the optimization index.The procedure is repeated for the next increments until the optimization index meets its target value,which is obtained according to the desired damping ratio for the overall structure.In other words,the desired overall damping ratio is the input to the proposed procedure,and the optimal placement and characteristics of the dampers are its output.It is observed that the optimal placement of a velocitydependent damper depends on the damping coefficient of the added damper,frequency of the excitation,and distribution of the mass,stiffness,and inherent damping of the main structure.     

非线性黏滞阻尼减震结构基于位移的设计方法

结合我国抗震设计规范,提出非线性黏滞阻尼减震结构基于位移的设计方法.根据减震结构的特点,将其性能划分为使用良好、人身安全和防止倒塌3个水平,并用层间位移角限值予以量化;以简化的方法计算非线性黏滞阻尼器的等效阻尼比.在此基础上将结构转化为等效单自由度体系,利用基于位移的设计方法对非线性黏滞阻尼减震结构进行设计,通过算例,介绍用该方法对框架结构进行非线性黏滞阻尼减震设计的设计过程.实例分析表明,提出的非线性黏滞阻尼减震结构基于位移的设计方法是可行的,并且与时程分析得出的平均结果吻合较好,而且该方法简单实用,便于操作,能够控制减震结构在不同强度水准地震作用下的性能.     

Direct displacement-based design for seismic retrofit of existing buildings using nonlinear viscous dampers

This paper presents a direct displacement-based design procedure for seismic retrofit of existing buildings using nonlinear viscous dampers according to equivalent linear systems. Unlike conventional methods, the equivalent linear viscous damping provided by the nonlinear viscous dampers is derived based on the assumption that the average energy dissipated between the linear and the nonlinear viscous dampers is equal. Also, the equivalent period and viscous damping for the equivalent linear systems which are used for representing the behavior of bare frames (the buildings without dampers) are derived from the concept of average storage energy and average dissipated energy, respectively. It is shown from nonlinear time-history analyses that the nonlinear action of the retrofitted structures can be reasonably captured by the presented direct displacement-based procedure.     

非线性粘滞阻尼器消能结构设计方法探讨

在建立非线形粘滞阻尼器消能结构性能曲线的基础上，建议了依据减震性能目标确定阻尼器参数的概略设计方法。提出了多自由度非线性粘滞阻尼器消能结构的等效阻尼比计算公式。在此基础上建议了适用于多自由度非线性粘滞阻尼器消能结构地震反应预测的模态叠加法，方法与时程分析结果对比吻合良好。为使各层阻尼器参数更好地满足减震性能要求，提出了将概略设计得到的层阻尼器参数依据减振性能目标进行调整的方法。     

Constant-ductility inelastic displacement ratios for displacement-based seismic design of self-centering structures

This paper focuses on constant-ductility inelastic displacement ratios of self-centering single-degree-of-freedom (SDF) systems with two different levels of energy dissipation capacity, in the presence of 5% viscous damping ratio. A statistical analysis is developed considering an earthquake database composed of 228 ground motions recorded in California with magnitudes greater than six and organized for NEHRP soil class, ground motion duration, and peak ground acceleration. The response of self-centering SDF systems with large variability of initial periods, ductility levels, and postyield stiffness ratios is investigated and compared with the responses of SDF systems with bilinear plastic, Clough, and Takeda hysteresis. The inelastic demand variation with soil class, initial period, postyield stiffness ratio, unloading stiffness degradation, ductility level, and hysteretic behavior is highlighted. Simple and conservative analytical estimates of constant-ductility inelastic displacement ratios for mean and 90th percentile values in terms of initial period, ductility level, and postyield stiffness ratio are proposed to allow the extension of the Displacement-Based Design via Inelastic Displacement Ratio (C_μDBD) to self-centering structural systems.