Passive Energy Dissipation Devices Research Articles

Empirical Evaluation of Cyclic Behavior of Rotational Friction Dampers with Different Metal Pads

.Passive energy dissipation devices have been widely used to reduce the maximum responses of structures under seismic loading. Recently, different types of passive energy devices are developed to improve seismic behavior of structures in new construction and retrofitting existing structures. Friction dampers are displacement dependent passive devices which dissipate energy using friction mechanism. Many different types of friction dampers have been proposed in recent years. This paper aims at investigating the cyclic behavior of a rotational friction damper with different friction pads under cyclic loading. To this end, experimental analysis is performed on a friction damper with four friction materials. The tested damper consists of steel plates, friction pads, preloaded bolts and hard washers. Cyclic loads are applied on damper specimens with four friction pads include: aluminum, galvanized steel, stainless steel, steel (St-37). The experimental results are studied according to FEMA-356 acceptance criteria to select the appropriate friction materials as friction pads for using in the friction damper.

Rocking damage‐free steel column base with friction devices: design procedure and numerical evaluation

SummaryEarthquake‐resilient steel frames, such as self‐centering frames or frames with passive energy dissipation devices, have been extensively studied during the past decade, but little attention has been paid to their column bases. The paper presents a rocking damage‐free steel column base, which uses post‐tensioned high‐strength steel bars to control rocking behavior and friction devices to dissipate seismic energy. Contrary to conventional steel column bases, the rocking column base exhibits monotonic and cyclic moment–rotation behaviors that are easily described using simple analytical equations. Analytical equations are provided for different cases including structural limit states that involve yielding or loss of post‐tensioning in the post‐tensioned bars. A step‐by‐step design procedure is presented, which ensures damage‐free behavior, self‐centering capability, and adequate energy dissipation capacity for a predefined target rotation. A 3D nonlinear finite element (FE) model of the column base is developed in abaqus. The results of the FE simulations validate the accuracy of the moment–rotation analytical equations and demonstrate the efficiency of the design procedure. Moreover, a simplified model for the column base is developed in OpenSees. Comparisons among the OpenSees and abaqus models demonstrate the efficiency of the former and its adequacy to be used in nonlinear dynamic analysis. A prototype steel building is designed as a self‐centering moment‐resisting frame with conventional or rocking column bases. Nonlinear dynamic analyses show that the rocking column base fully protects the first story columns from yielding and eliminates the first story residual drift without any detrimental effect on peak interstory drifts. The study focuses on the 2D rocking motion and, thus, ignores 3D rocking effects such as biaxial bending deformations in the friction devices. The FE models, the analytical equations, and the design procedure will be updated and validated to cover 3D rocking motion effects after forthcoming experimental tests on the column base. Copyright © 2017 John Wiley & Sons, Ltd.

Seismic response control of multi-story asymmetric-plan buildings using pin-supported structures with passive energy dissipation devices

This paper proposes a structural system that prevent low-rise wooden buildings from soft-story mechanisms under strong seismic excitations. The proposed system consists of a pin-supported frame (PSF) and passive energy dissipation devices, which are attached to the building from the outside. The PFS works to reduce the torsional vibration of the building and make the story drift of all the stories uniform, and the passive energy dissipation device further reduce the seismic response. First, the time-history response analysis of two-story asymmetric-plan wooden buildings is carried out to show the effectiveness of the proposed system. Then, the prediction formula of the axial force acting on the connection between the main structure and the PSF is derived, and its validity is confirmed by comparing with the result obtained from the time history analysis.

Performance-Based Seismic Design Of An Innovative HCW System With Shear Links based on IDA

Structural members yielding in shear are used in earthquake resistant systems, such as eccentrically braced steel frames and systems with passive energy dissipation devices, in a conscious effort to concentrate the energy dissipation capacity of the structure in components that can be repaired or replaced after a major earthquake. This paper presents an improved approach to a newly suggested design procedure of an innovative Hybrid Coupled Shear Wall (HCW) system consisting of a RC shear wall coupled with steel side columns via dissipative steel shear links. The primary design objective is to reduce or possibly avoid the damage in the RC wall while concentrating the seismic damage to the replaceable steel links which are shear critical, i.e. intended to fail in shear rather than flexure. To this purpose, a performance based approach is followed considering several limit states such as IO (Immediate Occupancy based on a limitation of the interstorey drifts), LS (Life Safety with yielding of the link, restoration possibilities of the links and limitation of the damages in the RC wall) and CP (near collapse situation with possible significant damages in the RC wall). The proposed design procedure is applied to several case studies which are analysed through nonlinear static and incremental dynamic analyses using finite element models in order to optimize the respective contribution of the wall, side columns as well as the links in terms of strength, stiffness and energy dissipation capacities.

Prototype Testing of a New Passive Energy Dissipation Device for Seismic Retrofit of Bridges

The increasingly demanding performance requirements trigger the development of new devices to eliminate the limitations concerning the post-earthquake performance of available seismic protection systems. The prerequisite for economical earthquake-resistant bridges is the structures’ capacity to absorb and dissipate a large amount of seismic energy. A widely considered strategy for enhancing this capacity is through the use of passive energy dissipation systems for seismic protection of structures. It has been known that majority of the available energy dissipation systems are non-usable after a major earthquake, which increases the risk of collapse during an aftershock. The focus of the current study is given to introduce a new type of passive energy dissipation device with a pending patent that is testified to have an improved energy dissipation capacity without suffering any damage while absorbing energy. Thus, the proposed damper does not require an immediate expensive replacement and keeps its operational capabilities and effectiveness during aftershocks. The paper presents the dynamic performance tests of the first full-scale prototype of the damper that eventually prove it to be a promising design with an improved energy dissipation capacity and stable behavior during and after the dynamic event.

Experimental Verification of a Cable-Stayed Bridge Model Using Passive Energy Dissipation Devices

To investigate the efficiency of passive energy dissipation devices in protecting cable-stayed bridges from severe damage when subjected to high-intensity ground motions, a 1/20-scale bridge model from a typical medium-span concrete cable-stayed bridge was designed, constructed, and tested on shake tables. Yielding steel damper (YSD) and viscous fluid damper (VFD) were used as passive energy dissipation devices in the transverse and longitudinal directions, respectively. The bridge models were then excited by two ground motions with different spectral characteristics in transverse and longitudinal directions accordingly, including the Chi-Chi earthquake wave and a site-specific artificial wave. The seismic responses of the bridge models with and without the passive devices were analyzed and compared. Both numerical and test results show that the YSD applied in the transverse direction could reduce the seismic responses of the towers effectively, and the VFD applied in the longitudinal direction could reduce the displacement of the deck effectively while simultaneously limiting the seismic responses of the towers. Therefore, it is suggested that the proposed energy dissipation system, consisting of YSD transversely and VFD longitudinally along with the sliding bearing, is applied in the cable-stayed bridges for better overall seismic performance compared to the traditional isolation system that provides efficiency only longitudinally.

Failure probability minimization of buildings through passive friction dampers

Summary This paper proposes a methodology for robust optimization of the failure probability of buildings subjected to stochastic earthquakes, using a less common type of passive energy dissipation device: the friction dampers. There is a lack of studies on optimal positions and parameters of passive friction dampers, and additionally, the few studies found in the literature consider the problem in a deterministic way. The robust optimization proposed in this paper is carried out through the recently developed backtracking search optimization algorithm, which is able to deal with optimization problems involving mixed discrete (positions) and continuous (friction forces) design variables. In order to take into account uncertainties present in both the system and the dynamic excitation (earthquakes), some parameters are modeled as random variables, and consequently, the structural response becomes stochastic. For illustration purposes, a 10-story building is analyzed. The results showed that the proposed method was able to reduce the failure probability in approximately 99% with only three friction dampers, installed in their best positions and with their optimized friction forces. The proposed methodology is quite general, and it is believed that it can be recommended as an effective tool for optimum design of friction dampers. Copyright © 2016 John Wiley & Sons, Ltd.

Seismic performance and optimal design of framed underground structures with lead-rubber bearings

Lead-rubber bearings (LRBs) have been used worldwide in seismic design of buildings and bridges owing to their stable mechanical properties and good isolation effect. We have investigated the effectiveness of LRBs in framed underground structures on controlling structural seismic responses. Nonlinear dynamic time history analyses were carried out on the well-documented Daikai Station, which collapsed during the 1995 Hyogoken-Nanbu earthquake. Influences of strength ratio (ratio of yield strength of LRBs to yield strength of central column) and shear modulus of rubber on structural seismic responses were studied. As a displacement-based passive energy dissipation device, LRBs reduce dynamic internal forces of framed underground structures and improve their seismic performance. An optimal range of strength ratios was proposed for the case presented. Within this range, LRBs can dissipate maximum input earthquake energy. The maximum shear and moment of the central column can achieve more than 50% reduction, whereas the maximum shear displacement of LRBs is acceptable.

COMPARATIVE STUDY OF EIGHT METALLIC YIELDING DAMPERS

The seismic resistance of structures can be enhanced by using passive energy dissipation devices in order to dissipate earthquake energy. One of these devices is metallic yielding dampers which is low-cost, but highly-efficient. This paper aims to compare four key variables among eight metallic yielding dampers. Theses four parameters are equivalent viscose damping ratio, large load to weight, ductility and cumulative displacement. The dampers were selected based on the availability of the experimental data in the literature. As the first step of the methodology eight particular dampers with its load-displacement curve were carefully chosen to study. Three dissimilar last loops of force-displacement hysteresis were selected and drawn for each damper. Then the above mentioned parameters were calculated and compared to get results and draw conclusion. The outcomes reveal the relationship of the four studied parameters with each other. The results show there is a relationship between the mechanisms of energy dissipation with the specific range of equivalent viscous damping ratio in the studied metallic dampers.

Cyclic behavior of shear-and-flexural yielding metallic dampers

The energy dissipation potential of a metallic damper largely depends on the hysteretic response achieved due to the inelastic deformation of plates under either axial or flexural or shear loading. In this study, a passive energy dissipation device consisting of a series of steel plates capable of yielding in both flexure and shear has been experimentally investigated under cyclic loading. Two end plates of X-configuration are allowed to yield under flexural action, whereas a rectangular web plate of the device is allowed to dissipate energy through shear yielding. Three shear-and-flexural yielding damping (SAFYD) devices are studied by varying the size of both flexure and shear plates. The main parameters investigated are load-carrying capacity, hysteretic response, energy dissipation, equivalent viscous damping, and ductility. A finite element analysis has been carried out to predict the ultimate resistance and hysteretic response of the test specimen. The predicted results matched reasonably well with the test results. Finally, a design procedure has been proposed to proportion the flexure and shear plates of SAFYD devices for a given lateral load demand.

A low damage and ductile rocking timber wall with passive energy dissipation devices

In conventional seismic design, structures are assumed to be fixed at the base. To reduce the impact of earthquake loading, while at the same time providing an economically feasible structure, minor damage is tolerated in the form of controlled plastic hinging at predefined locations in the structure. Uplift is traditionally not permitted because of concerns that it would lead to collapse. However, observations of damage to structures that have been through major earthquakes reveal that partial and temporary uplift of structures can be beneficial in many cases. Allowing a structure to move as a rigid body is in fact one way to limit activated seismic forces that could lead to severe inelastic deformations. To further reduce the induced seismic energy, slip-friction connectors could be installed to act both as hold-downs resisting overturning and as contributors to structural damping. This paper reviews recent research on the concept, with a focus on timber shear walls. A novel approach used to achieve the desired sliding threshold in the slip-friction connectors is described. The wall uplifts when this threshold is reached, thereby imparting ductility to the structure. To resist base shear an innovative shear key was developed. Recent research confirms that the proposed system of timber wall, shear key, and slip-friction connectors, are feasible as a ductile and lowdamage structural solution. Additional numerical studies explore the interaction between vertical load and slip-friction connector strength, and how this influences both the energy dissipation and self-centring capabilities of the rocking structure.

Seismic Design of a Long-Span Cable-Stayed Bridge with Fluid Viscous Dampers

AbstractAs a passive energy dissipation device, the fluid viscous damper (FVD) is effective for mitigating wind or seismic load-induced vibrations. In this paper, the effects of FVDs for a cable-stayed bridge under randomly generated earthquake excitation are investigated. The FVD is modeled as a simplified Maxwell model, which consists of a linear spring in series with a nonlinear dashpot. The pile is modeled as a beam on the nonlinear Winkler foundation, and the soil–pile interactions are simulated by using continuously distributed hysteretic springs and viscous dashpots placed in parallel. Three random ground motions are generated from the earthquake risk assessment based on the seismotectonics and seismicity analysis of the bridge location. The seismic response of the cable-stayed bridge with FVD considering soil–structure interactions (SSIs) is obtained by solving the equations of motion in the time domain using a direct integration method. Parametric studies are conducted for the two key parameters ...

Desempeño sísmico de un pórtico con disipadores de energía pasivos de placas ranuradas de acero

This paper evaluates two types of hysteretic passive energy dissipation devices (steel slit plates). These devices are low-cost and easy to build and install. The seismic performance of three structural models were studied with shake table tests: a frame without energy dissipation device and two frames with two types of steel slit plates. The models were instrumented with accelerometers, strain gages and LVDTs, and were subjected to two types of earthquakes signals: a regional earthquake and a near-field ground motion. The results of laboratory tests suggest that the frame with steel slit plates have up to 90% less seismic drift than the frame without rehabilitation. This is because steel slit plates dissipated a large portion of the input energy supplied by earthquakes and the damage to the parent structure was minimized. Rev. ing. constr. [online]. 2014, vol.29, n.3, pp. 283-298. ISSN 0718-5073. http://dx.doi.org/10.4067/S0718-50732014000300005

A firefly algorithm for the design of force and placement of friction dampers for control of man-induced vibrations in footbridges

It is known that the use of passive energy dissipation devices, as friction dampers, reduces significantly the dynamic response of structures subjected to dynamic actions. However, the parameters of each damper as well as the best placement of these devices remain difficult to determine. Although some studies on optimization of tuned mass damper and viscous/viscoelastic dampers are being developed, works on optimum use of friction dampers is still lacking. Thus, in this paper, the simultaneous optimization of force and placement of friction dampers is proposed. To solve this optimization problem, the recently developed firefly algorithm is employed, which is able to deal with non-convex optimization problems, involving mixed discrete and continuous variables. For illustration purposes, two common footbridges are analyzed, in which the cost function is to minimize the maximum acceleration of the structures, whereas forces and positions of friction dampers are the design variables. The results showed that the proposed method was able to determine the optimum friction forces of each damper as well as their best positions in the structures. The maximum acceleration was reduced in more than 95 % for the Warren truss footbridge, with three friction dampers, and in more than 92 % for the Pratt truss footbridge, with only two friction dampers. In addition, the proposed methodology is quite general and it is believed that it can be recommended as an effective tool for optimum design of friction dampers for structural response control. Thus, this paper shows that the design of friction dampers can be done in a safe and economic way.

Viscous Dampers Utilized at an Operating Electronic Facility for Reducing Seismic Risk

Using supplemental energy dissipation devices into the structure to increase the damping ratio for reducing the responses of seismic activity has become more and more popular. This paper presents a case study of seismic retrofit strategy, utilizing a type of passive energy dissipation device, namely, the viscous damper, in order to make an ongoing chips produced facility resistant to seismic activity. The building in question was a chips produced facility belonging to a semiconductor manufacturing company. This was a double FAB where the structure system was divided into an island building and an RC shell. The retrofit involved installing 44 non-linear dampers between the island building and the RC shell. This was due to the significant differences in the fundamental vibration periods. This paper will present the rationale of making a decision on the parameters of the dampers to give the optimum retrofit strategy.

등방성 이력형 강재댐퍼를 이용한 RC 라멘조 아파트건물의 지진응답 개선

수동형 제진장치를 이용하는 제진구조는 수년간 개발이 지속되고 있으며, 1990년대 중반이후로 여러 나라들에서 실무적인 적용이 빠르게 증가되고 있다. 국내의 경우 이러한 제진장치 중 강재이력형 댐퍼가 비교적 저렴한 비용과 설치와 관리가 용이하다는 이유로 건물의 내진설계를 위하여 보편적으로 많이 적용되고 있다. 이 논문에서는 건물의 지진응답을 개선하기 위하여 적용된 소위 카고메댐퍼로 불리우는 등방성 강재이력형 댐퍼(Isotropic Hysteretic Metallic Damper, IHMD)의 유효성에 대한 해석적인 사례연구를 제시하고 있다. 연구대상 건물은 18층 규모의 철근콘크리트 라멘조 아파트건물로 해석결과를 통하여 IHMD의 실효성을 실증적으로 보여주고 있다. 해석결과는 IHMD가 건물의 지진응답을 줄일 수 있는 매우 효과적인 방법임을 검증하고 있다. Passive energy dissipation systems for seismic applications have been under development for a number of years with a rapid increase in implementations starting in the mid-1990s in many countries. A metallic hysteretic damper has most commonly been used for seismic protection of structures in domestic area because they present high energy-dissipation potential at relatively low cost and easy to install and maintain. This paper presents an analytical case study of the effectiveness of isotropic hysteretic metallic damper(IHMD) called Kagome as a passive dissipative device in reducing structural response during seismic excitation. An eighteen-story RC framed apartment building is studied with and without IHMD. Results demonstrate the feasibility of these techniques for seismic mitigation. The inclusion of supplemental passive energy dissipation devices in the form of IHMD proved to be a very effective method for significantly reducing the seismic response of the building investigated.

Robust design optimization of friction dampers for structural response control

SUMMARY It is known that the use of passive energy dissipation devices, as friction dampers, reduces considerably the dynamic response of a structure subjected to earthquake ground motions. However, the parameters of each damper as well as the best placement of these devices remain difficult to determine. Thus, in this paper, robust design optimization of friction dampers to control the structural response against earthquakes is proposed. In order to take into account uncertainties present in the system, some of its parameters are modeled as random variables, and consequently, the structural response becomes stochastic. To perform the robust optimization of such system, two objective functions are simultaneously considered: the mean and variance of the maximum displacement. This approach allows finding a set of Pareto-optimal solutions. A genetic algorithm, the NSGA-II (Nondominated Sorting Genetic Algorithm), is applied to solve the resulting multi-objective optimization problem. For illustration purposes, a six-story shear building is analyzed. The results showed that the proposed method was able to reduce the mean maximum displacement in approximately 70% and the variance of the maximum displacement in almost 99% with only three dampers. Copyright © 2014 John Wiley & Sons, Ltd.

EXPERIMENTAL STUDY AND APPLICATION OF METALLIC YIELDING–FRICTION DAMPER

In this paper, a new idea for designing the metallic yielding–friction damper (MYFD) is presented based on the principle that the metallic plate can be used for yielding and can be the friction component of the passive energy dissipation device (PEDD). This type of damper is so-called the MYFD, because it consists of yielding part and friction part. Phased energy dissipation is realized throughout the metallic yielding plate and friction plate combination where friction behavior is prior to yielding behavior. The quasi-static test with two small-scale MYFDs is carried out. Then, it is applied in an actual reinforced concrete building. The design method and fitting process of the MYFDs are introduced. In order to compare seismic responses of the building with and without the dampers, a dynamic analysis of the building under earthquakes is performed. The results show that the MYFD presented here possess good ability of seismic energy dissipation.

Risk-based seismic performance assessment of Yielding Shear Panel Device

Yielding Shear Panel Devices (YSPDs) have recently been proposed to facilitate passive energy dissipation of building frames during seismic activity and hence protect major structural components from excessive stress. A YSPD is composed of a thin steel diaphragm plate encapsulated within a square hollow steel tube, which is bolted to the structure to utilize the inelastic shear deformation capability of the steel diaphragm plate for energy dissipation and for consequent modification to the structural response. This paper conducts probabilistic performance evaluation to assess the appropriateness of YSPDs given uncertainty in the occurrence and intensity of earthquakes, material strength, stiffness, structural response, etc., and evaluate performance based on size, number and configuration of YSPDs. A fragility analysis is conducted, which identifies the probability of exceeding a structural damage level depending on ground motion intensity, along with a limit state probability analysis to quantify the annual exceedance probability of a specified damage level. A mathematical model to represent YSPDs in a finite element code is developed and the model is used for analyzing a case study steel moment frame with alternative YSPD designs. The study reveals the potential for considerable reduction in the median fragility and annual limit state exceedance probability due to the inclusion of YSPDs through a V-brace system. However, the effectiveness of different YSPD orientations is varied and their relative performance levels are discussed in detail. Overall, the study shows the suitability of YSPD as a passive energy dissipation device and the potential to utilize this device to help achieve performance-based objectives for buildings in seismic zones.

Buckling-Restrained-Lug Connection for Energy Dissipation

Under extreme loading conditions such as an earthquake event considerable amount of energy is imparted to a structure. To protect the structure and to minimize damages, a method is to divert a portion of the input energy into designated energy dissipating devices. A new energy dissipation device is presented in this paper. The device is referred to as Buckling-Restrained-Lug (BRL) which can be incorporated in structural joints. The device is composed of a short segment of a steel strut embedded inside a mortar filled jacket which makes the BRL's capacity governed by the squash load under axial tension or compression. The BRL dissipates energy through axial yielding of the steel strut. Analytical, finite element modeling and experimental results of the proposed BRL are presented and compared. Implementation of the BRL in a beam-to-column connection that results in a dissipative partial-moment-resisting joint is proposed. Based on the obtained results, the paper advocates the consideration of the BRL as a viable, compact and low-cost passive energy dissipation device.