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1.
大底盘多塔楼结构的混合隔震控制 总被引：2，自引：0，他引：2
结合某实际工程,针对大底盘多塔楼结构提出混合隔震的控制策略,即对大底盘上的一栋或多栋塔楼采用隔震技术,并在隔震层附设一定数量的被动、主动或半主动的减震控制装置。建立了这种大底盘多塔楼结构混合隔震控制体系的运动方程,方程中各塔楼与下部结构及隔震层之间的刚度解耦,并考虑了隔震层的非线性。研究中比较了被动非线性粘滞阻尼器,半主动变孔隙阻尼器与理想主动控制时的减震控制效果。结果表明,这种混合隔震体系可以有效地减小上部塔楼与下部结构的地震反应,提高大底盘多塔楼结构的抗震安全性,取得明显的经济和社会效益。半主动变孔隙阻尼器可以极好地追踪理想主动控制力,取得与理想主动控制相近的减震控制效果。被动非线性粘滞阻尼器也能取得较好的减震效果,且易于维护,经济性较好,从工程应用的角度来看更为现实可行,具有较好的应用推广价值。 相似文献
2.
Francesca Barbagallo Melina Bosco Edoardo M. Marino Pier Paolo Rossi 《地震工程与结构动力学》2018,47(13):2682-2707
A design procedure for seismic retrofitting of concentrically and eccentrically braced frame buildings is proposed and validated in this paper. Rocking walls are added to the existing system to ensure an almost uniform distribution of the interstorey displacement in elevation. To achieve direct and efficient control over the seismic performance, the design procedure is founded on the displacement‐based approach and makes use of overdamped elastic response spectra. The top displacement capacity of the building is evaluated based on a rigid lateral deformed configuration of the structure and on the ductility capacity of the dissipative members of the braced frames. The equivalent viscous damping ratio of the braced structure with rocking walls is calculated based on semi‐empirical relationships specifically calibrated in this paper for concentrically and eccentrically braced frames. If the equivalent viscous damping ratio of the structure is lower than the required equivalent viscous damping ratio, viscous dampers are added and arranged between the rocking walls and adjacent reaction columns. The design internal forces of the rocking walls are evaluated considering the contributions of more than one mode of vibration. The proposed design procedure is applied to a large set of archetype braced frame buildings and its effectiveness verified by nonlinear dynamic analysis. 相似文献
3.
Minimum‐cost optimization of nonlinear fluid viscous dampers and their supporting members for seismic retrofitting 
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下载免费PDF全文 This paper presents an effective approach for achieving minimum‐cost designs for seismic retrofitting using nonlinear fluid viscous dampers. The damping coefficients of the dampers and the stiffness coefficients of the supporting braces are designed by an optimization algorithm. A realistic retrofitting cost function is minimized subject to constraints on inter‐story drifts at the peripheries of frame structures. The cost function accounts for costs related to both the topology and the sizes of the dampers. The behavior of each damper‐brace element is defined by the Maxwell model, where the force–velocity relation of the nonlinear dampers is formulated with a fractional power law. The optimization problem is first posed and solved as a mixed integer problem. For the reduction of the computational effort required in the optimization, the problem is then reformulated with continuous variables only and solved with a gradient‐based algorithm. Material interpolation techniques, which have been successfully applied in topology optimization and in multi‐material optimization, play a key role in achieving practical final design solutions with a reasonable computational effort. Promising results attained for 3‐D irregular frames are presented and discussed. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
4.
消能减震技术用于C类框架学校建筑提高一度抗震设防加固的探讨 总被引：1，自引：0，他引：1
针对既有的C类框架学校建筑提高一度抗震设防的加固目标,从地震作用计算、结构抗震验算和抗震构造措施等方面详细分析了其中的加固难点,指出了应用传统抗震加固方法的一些不足之处,探讨了应用消能减震技术进行结构提高一度抗震设防加固的可行性;并以某C类框架学校建筑加固工程为实例,从减震控制效果分析、弹塑性变形验算、消能部件影响评价、抗震构造措施核查4个方面论证了消能减震加固方法的有效性和可操作性。结果表明,消能减震技术在C类框架学校建筑抗震加固中具有一定的应用优势,不但能有效控制结构的地震响应,而且依据减震效果可以适当降低结构的抗震构造要求。因此,只要通过合理的消能减震加固设计,再辅以额外的局部加强处理,完全可以实现C类框架学校建筑提高一度抗震设防的加固目标需求。 相似文献
5.
消能减振房屋抗震设计方法研究述评 总被引：3，自引：0，他引：3
阐述了安装有粘滞流体阻尼器的消能减振房屋抗震设计的原理和方法，包括阻尼器的工作原理和计算模型，性能试验和检验的标准，附加阻尼比公式的推导和抗震设计方法等。 相似文献
6.
This study describes the seismic performance of an existing five storey reinforced concrete building which represents the typical properties of low-rise non-ductile buildings in Turkey. The effectiveness of shear walls and the steel bracings in retrofitting the building was examined through nonlinear static and dynamic analyses. By using the nonlinear static analysis, retrofitted buildings seismic performances under lateral seismic load were compared with each other. Moreover, the performance points and response levels of the existing and retrofitting cases were determined by way of the capacity-spectrum method described in ATC-40 (1996). For the nonlinear dynamic analysis the records were selected torepresent wide ranges of duration and frequency content. Considering the change in the stiffness and the energy dissipation capacities, the performance of the existing and retrofitted buildings were evaluated in terms of story drifts and damage states. It was found that each earthquake record exhibited its own peculiarities, dictated by frequency content, duration, sequence of peaks and their amplitude. The seismic performance of retrofitted buildings resulted in lower displacements and higher energy dissipation capacity depending mainly on the properties of the ground motions and the retrofitting strategies. Moreover, severe structural damage (irreparable or collapse) was observed for the existing building. However, buildings with retrofit alternatives exhibited lower damage levels changing from no damage to irreparable damage states. 相似文献
7.
Nonstationary stochastic response of structural systems equipped with nonlinear viscous dampers under seismic excitation 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 Nonlinear viscous dampers are supplemental devices widely used for enhancing the performance of structural systems exposed to seismic hazard. A rigorous evaluation of the effect of these damping devices on the seismic performance of a structural system should be based on a probabilistic approach and take into account the evolutionary characteristics of the earthquake input and of the corresponding system response. In this paper, an approximate analytical technique is proposed for studying the nonstationary stochastic response characteristics of hysteretic single degree of freedom systems equipped with viscous dampers subjected to a fully nonstationary random process representing the seismic input. In this regard, a stochastic averaging/linearization technique is utilized to cast the original nonlinear stochastic differential equation of motion into a simple first‐order nonlinear ordinary differential equation for the nonstationary system response variance. In comparison with standard linearization schemes, the herein proposed technique has the significant advantage that it allows to handle realistic seismic excitations with time‐varying frequency content. Further, it allows deriving a formula for determining the nonlinear system response evolutionary power spectrum. By this way, ‘moving resonance’ effects, related to both the evolutionary seismic excitation and the nonlinear system behavior, can be observed and quantified. Several applications involving various system and input properties are included. Furthermore, various response parameters of interest for the seismic performance assessment are considered as well. Comparisons with pertinent Monte Carlo simulations demonstrate the reliability of the proposed technique. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
8.
Simultaneous topology and sizing optimization of viscous dampers in seismic retrofitting of 3D irregular frame structures 下载免费PDF全文
下载免费PDF全文 A new methodology for performance‐based optimal seismic retrofitting using a limited number of size groups of viscous dampers is presented. The damping coefficient of each size group of dampers is taken as a continuous variable and is determined by the optimization algorithm. Furthermore, for each potential location, a damper of a single size group is optimally assigned, if any. Hence, the formulation presents a large step forward towards practical optimal design of dampers. The key for achieving an efficient optimization scheme is the incorporation of material interpolation techniques that were successfully applied in other structural optimization problems of discrete nature. This results in a very effective optimization methodology that is expected to be very efficient for large‐scale structures. The proposed approach is demonstrated on several example problems of 3D irregular frame structures. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all types of dampers are designed by the same procedure, actual seismic performance of the building may differ from one to the others. In this study, a nine-story benchmark steel building is established, and three different and typical types of dampers are designed according to the Chinese Building Code to realize structural vibration control under strong earthquake excitation. The seismic response of the prototype building equipped with a viscoelastic damper, viscous damper and buckling-restrained brace(BRB) subjected to 10 earthquake records are calculated, and Incremental Dynamic Analysis(IDA) is performed to describe progressive damage of the structure under increasing earthquake intensity. In the perspective of fragility, it shows that the viscoelastic damper has the highest collapse margin ratio(CMR), and the viscous damper provides the best drift control. Both the BRB and viscoelastic dampers can effectively reduce the floor acceleration responses in the mid-rise building. 相似文献
10.
This paper presents an effective approach for achieving minimum cost designs for seismic retrofitting using viscous fluid dampers. A new and realistic retrofitting cost function is formulated and minimized subject to constraints on inter-story drifts at the peripheries of frame structures. The components of the new cost function are related to both the topology and to the sizes of the dampers. This constitutes an important step forward towards a realistic definition of the optimal retrofitting problem. The optimization problem is first posed and solved as a mixed-integer problem. To improve the efficiency of the solution scheme, the problem is then re-formulated and solved by nonlinear programming using only continuous variables. Material interpolation techniques, that have been successfully applied in topology optimization and in multi-material optimization, play a key role in achieving practical final design solutions with a reasonable computational effort. Promising results attained for 3-D irregular frames are presented and compared with those achieved using genetic algorithms. 相似文献
11.
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。 相似文献
12.
A two‐step direct method for estimating the seismic response of nonlinear structures equipped with nonlinear viscous dampers 下载免费PDF全文
下载免费PDF全文 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. 相似文献
13.
On the dimensioning of viscous dampers for the mitigation of the earthquake-induced effects in moment-resisting frame structures 总被引：1，自引：1，他引：0
Michele Palermo Saverio Muscio Stefano Silvestri Luca Landi Tomaso Trombetti 《Bulletin of Earthquake Engineering》2013,11(6):2429-2446
The effectiveness of viscous dampers in mitigating the seismic excitation impacts upon building structures has been widely proved. Recently, with reference to the specific case of equal mass, equal stiffness, shear-type structures, the authors developed a direct practical procedure which gives the mechanical characteristics of the manufactured viscous dampers capable of providing the frame structure with a prescribed value of the first damping ratio. In this paper, a comprehensive rational framework is presented, which allows to formally extend the validity of the proposed procedure to the more realistic case of a generic moment-resisting frame structure. Also the influence of various lateral stiffness distributions is investigated. 相似文献
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16.
Direct displacement-based design for seismic retrofit of existing buildings using nonlinear viscous dampers 总被引：1，自引：0，他引：1
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. 相似文献
17.
Selcuk Bas Chuan-Zhi Dong Nurdan M. Apaydin Alper Ilki F. Necati Catbas 《地震工程与结构动力学》2020,49(14):1496-1518
The effects of hanger replacement from inclined to vertical configuration on seismic response of long-span suspension bridges are investigated considering multi-support earthquake excitation. The Bosphorus Bridge is investigated due to its recent comprehensive rehabilitation, mainly involving hanger replacement. The finite-fault stochastic simulation method (FINSIM) is utilized for multi-point earthquake time-history generation. The developed finite element (FE) model both for the inclined and vertical hanger arrangement are verified through the structural health monitoring (SHM) data. Based on the comparative analysis, the tension force of vertical hangers is found to be lower than that of inclined hangers, whereas the tension force of the main and back-stay cables remains the same. The compressive axial force of the deck decreases relatively in the case of the vertical hanger arrangement, whereas the cross-sectional forces at the tower base section increase. The approach viaducts are not affected by the vertical hanger arrangement. According to the demand/capacity ratios for damage estimation under the max. earthquake (2475 years return period), structural damage on the tower base section may be expected for both hanger arrangements, while these sections perform well under design scenario earthquake. The expansion joint of the bridge with inclined hangers is also estimated to be damaged; however, this displacement is lower in the case of the vertical hanger arrangement due to the viscous dampers. The findings also reveal that a change in hanger form of a suspension bridge can necessitate other structural retrofit, such as using viscous dampers to limit longitudinal displacements of the deck and retrofitting the bridge towers. 相似文献
18.
An alternative approach for the seismic rehabilitation of existing RC buildings using seismic isolation 下载免费PDF全文
下载免费PDF全文 Usually, buildings with seismic isolation are designed to comply with an operational building performance level after strong earthquakes. This approach, however, may limit the use of seismic isolation for the seismic rehabilitation of existing buildings with low lateral strength or substandard details, because it often requires invasive strengthening measures in the superstructure or the use of expensive custom‐made devices. In this paper, an alternative approach for the seismic rehabilitation of existing buildings with seismic isolation, based on the acceptance of limited plastic deformations in the superstructure under strong earthquakes, is proposed and then applied to a real case study, represented by a four‐storey RC frame building. Nonlinear response‐time histories analyses of an accurate model of the case‐study building are carried out to evaluate the seismic performances of the structure, comparing different rehabilitation strategies with and without seismic isolation. Initial costs of the intervention and possible (future) repair costs are then estimated. Based on the results of this study, values of the behavior factor (i.e. response modification factor) higher than those adopted in the current codes for base‐isolated buildings are tentatively proposed. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
19.
Design of hysteretic dampers with optimal ductility for the transverse seismic control of cable‐stayed bridges 下载免费PDF全文
下载免费PDF全文 Alfredo Camara Roberto Cristantielli Miguel A. Astiz Christian Málaga‐Chuquitaype 《地震工程与结构动力学》2017,46(11):1811-1833
Cable‐stayed bridges require a careful consideration of the lateral force exerted by the deck on the towers under strong earthquakes. This work explores the seismic response of cable‐stayed bridges with yielding metallic dampers composed of triangular plates that connect the deck with the supports in the transverse direction. A design method based on an equivalent single‐degree of freedom approximation is proposed. This is proved valid for conventional cable‐stayed bridges with 200‐ and 400‐m main spans, but not 600 m. The height of the plates is chosen to (1) achieve a yielding capacity that limits the maximum force transmitted from the deck to the towers, and to (2) control the hysteretic energy that the dampers dissipate by defining their design ductility. In order to select the optimal ductility and the damper configuration, a multi‐objective response factor that accounts for the energy dissipation, peak damper displacement and low‐cycle fatigue is introduced. The design method is applied to cable‐stayed bridges with different spans and deck–support connections. The results show that the dissipation by plastic deformation in the dampers prevents significant damage in the towers of the short‐to‐medium‐span bridges under the extreme seismic actions. However, the transverse response of the towers in the bridge with a 600‐m main span is less sensitive to the dampers. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
20.
Buildings are continually subject to dynamic loads, such as wind load, seismic ground motion, and even the load from internal utility machines. The recent trend of constructing more flexible high‐rise buildings underscores the importance of including viscoelastic dampers in building designs. Viscoelastic dampers are used to control the dynamic response of a building. If the seismic design is based only on the linear response spectrum, considerable error may occur when calculating the seismic response of a building; rubber viscoelastic dampers show non‐linear hysteretic damping that is quite different from viscous damping. This study generated a non‐linear response spectrum using a non‐linear oscillator model to simulate a building with viscoelastic dampers installed. The parameters used in the non‐linear damper model were obtained experimentally from dynamic loading tests. The results show that viscoelastic dampers effectively reduce the seismic displacement response of a structure, but transmit more seismic force to the structure, which essentially increases its seismic acceleration response. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献