Experimental Study of Hysteretic Steel Damper for Energy Dissipation Capacity (original) (raw)

Numerical analysis of U-shaped hysterisis steel damper with energy absorber for seismic areas

IOP Conference Series: Materials Science and Engineering

This paper investigates one type of metallic dampers used in many large buildings in seismic areas. The previous studies have shown a possibility of the introduced damper to act as a damper as well as energy absorber through yielding on some parts of the damper. However, the occurred yielding caused a plastic deformation after unloading. The study aims to substitute the previous critical area to another part which is considerably uncritical during loading. Therefore, an additional part in the form of a slender column is inserted into the damper. The bottom part of the column is clamped to the base plate of the damper. There is a restoring moment acting on the column which was able to restore a large displacement of the damper to at least a small residual plastic displacement after unloading. A stiffness, strength and energy dissipation of the modified damper is determined by a nonlinear finite element technique which involves both geometrically and materially nonlinearities. The mod...

Improvement of Seismic Performance of Seven Story Steel Building with Hysteretic Steel Dampers Under Severe Seismic Excitation

The uses of supplementary hysteretic steel dampers have been recognized as effective and inexpensive techniques to reduce seismic responses of structural systems induced by a major earthquake. During a large earthquake event, these dampers will absorb the earthquake input energy to the structure through hysteretic behavior of its elements, where the main members are designed to remain elastic and/or within low inelastic deformation. The purpose of this paper is to study the effectiveness of the hysteretic dampers improving the structural performance of a steel building subjected to a major earthquake excitation. To do this, seven story's steel building with and without hysteretic steel dampers are investigated using non-linier dynamic time history analysis under a set of selected ground motion records. The ground motions are matched to the response spectrum design of the National Indonesian Standard of seismic hazard map. In this study, hysteretic steel dampers are applied with various stiffness ratio values in the steel bracing of the Chevron types configurations. To quantify the structure's performance, a damage indicator derived from the energy damage model is introduced and evaluated. Finally, the seismic performance of the building with and without hysteretic steel dampers are discussed and compared.

Applications of hysteretic steel dampers for controlling the seismic damage in steel frames

The aim of seismic design is not intended to make earthquake-proof structures that will not experience any damage even during a strong earthquake; such structures will be too costly. However, controlling the damage to the desired level is a necessity for buildings with a particular purpose such as hospital, fire and police station, nuclear facilities, buildings that contain hazardous material, and other building that is critical for emergencies and defense. In this paper, a four-story steel frame, both with and without hysteretic steel damper are investigated in order to account the effect of stiffness ratio, and SR (ratio between steel damper and braces stiffness to the bare frame stiffness) in the global structural damage. For these purposes, three ground motions which are compatible to the design spectrum response in the Indonesian building code were selected to be applied to the structure with a stiffness ratio (SR) of 2, 3, 4 and 5 using a non-linear dynamic time history analysis. In this context, the damage index based on the works of Park and Ang is used as the criteria to define global structural damage, while story drift index is used as the criteria to measure the seismic performance level. The results demonstrated that the use of steel damper not only enhances the seismic performance, but it also reduces the damage index of the investigated structure. Furthermore, the damage index and story drift index are influenced by the stiffness ratio, in which the stiffness ratio of 4 (four) provides the smallest damage index and inter-story drift index. Moreover, the damage index and inter-story drift index were also affected by ground motions characteristics.

Modelling Hysteretic Behaviour of U-shaped Steel Dampers

ce/papers 1(2-3):3239-3248, 2017

Conventional approach to earthquake resistant building design relies upon strength, stiffness, and inelastic deformation capacity, which are great enough to withstand a given level of design earthquake effects. However, modern approach in today's designs aims to mitigate seismic energy before the input energy reaches the structural elements. Dissipating seismic energy through the inelastic deformation of metallic dampers is one of the cost effective solutions. After appearing concept of dissipating energy through the inelastic deformation (mainly yielding and post yielding) of metallic dampers, numerous types of metallic dampers, such as X-shaped, J-shaped, U-shaped, shear panel, triangular plate dampers have been developed and their effectivenesses have been proved both theoretically and experimentally. Inelastic hysteretic behaviour of U-shaped devices is somewhat complex and varies with geometry of the damper. To address this issue and possibly attain some practical results, this present paper focuses on modelling hysteretic behaviour of U-shaped dampers. ABAQUS has been used as the computational tool in which a finite element model made of the C3DR8 solid element is adopted. Nonlinear kinematic and isotropic hardening material assumptions are considered to determine cyclic behaviour at 0º, 45º and 90º loading directions. For each analysis, effective stiffness, effective damping ratio, and maximum reaction forces (i.e. horizontal strengths) of the damper are calculated to evaluate performance. As an additional parameter, two different loading protocols are taken into consideration. Hysteretic curves and deformed shapes of a selected damper type taken from an existing experimental work and this numerical study show very good agreement proving that the modelling assumptions made during the analyses are appropriate and sufficient for a better prediction of behaviour. Additional numerical analyses on several dampers under various loading protocols reveal that effective damping ratio of the damper is more than ξeff =40% at the maximum displacement level due to significant energy dissipation through plastic deformation of the damper. A numerical example of mixed use of U-shaped steel dampers and rubber isolation bearings on a selected two story steel framed building is also discussed.

HYSTERETIC DAMPERS FOR THE PROTECTION OF STRUCTURES FROM EARTHQUAKES

The development of hysteretic dampers for the protection of structures against earthquake attack, carried out at the Physics and Engineering Laboratory over the past six years, is described. Details of both steel and lead devices and their application to bridges and base isolated buildings are given.

Experimental Evaluation of Hysteretic Behavior of Rhombic Steel Plate Dampers

Advances in Mechanical Engineering, 2014

Rhombic mild-steel plate damper (also named rhombic added damping and Stiffness (RADAS)) is a newly proposed and developed bending energy dissipation damper in recent years, and its mechanical properties, seismic behavior, and engineering application still need further investigations. In order to determine the basic mechanical performance of RADAS, fundamental material properties tests of three types of mild-steel specimen including domestically developed mild-steel material with low yield strength were carried out. Then, a quasistatic loading test was performed to evaluate the mechanical performance and hysteretic energy dissipation capacity of these rhombic mild-steel dampers manufactured by aforementioned three types of steel materials. Test results show that yield strength of domestically developed low yield strength steel (LYS) is remarkably lower than that of regular mild steel and its ultimate strain is also 1/3 larger than that of regular mild steel, indicating that the low ...

THE APPLICATION OF INNOVATIVE STEEL DAMPING DEVICES TO BUILDING STRUCTURES

Over the last many years, a large amount of research has been devoted into developing effective earthquake resistant systems in order to raise the seismic performance level of structures. This paper proposes innovative new type of steel damper, based on the yielding of cantilever type steel plates for seismic protection of building structures. To maximize the energy dissipation of the device, the optimization geometry of a steel plate was firstly developed. The hysteretic behavior and energy dissipation capacity were then investigated, via component tests under cyclic loads. The experimental results indicated that the damping device has stable restoring force characteristics, and a high energy dissipation capacity. In addition, structural systems were tested to verify the performance of damping devices.

Performance of profiled I shaped dampers as energy dissipation system for braced steel structure

IRJET, 2023

During an earthquake, severe damages may occur in the structural elements. In order to reduce the damages by earthquakes, dampers are used in the structures. It controls earthquake induced vibrations on buildings. Dampers absorb a significant amount of seismic energy to the structure and which is dissipated by them. In this study, I shaped profiled damper (IPDs) are used. The IPDs as ductile element in concentrically braced frame systems which is responsible for energy absorption and energy dissipation. Dampers are easily replaceable and economically feasible which controls the seismic mitigation on steel structure. The main objective of this study is to perform the lateral loading testing on a braced steel frame with and without damper. The parametric study is carried out by changing the parameters of the IPD dimensions to find the optimum size that is bests suited for the seismic performance of the structure. This study also focus on obtaining hysteresis performance and the energy dissipation capacity by placing IPD damper in a different bracing system. It is expected that using IPD damper in braced steel frame, the energy dissipation capacity is improved avoid buckling of bracing and the output parameters like stiffness, total dissipated energy, and hysteresis behavior are compared. The complete analytical model and extensive parametric studies will be carried out usinga ANSYs software.

An innovative hysteretic damper with adaptive post-elastic stiffness for seismic protection of bridges

Bridge Structures, 2016

A new hysteretic damper for seismic protection of highway bridges is presented. The Multi-directional Torsional Hysteretic Damper (MTHD) works based on torsional yielding of steel cylindrical cores. The device demonstrates a hyperbolic post-elastic stiffness as a result of its special working mechanism which produces this geometric hardening effect. The post-elastic stiffness was found to be effective in limiting the lateral displacement of the seismic-isolated bridge decks in near-fault. Results of nonlinear time history analyses revealed the adaptive behavior of the device which is a result of this gradual hardening feature, such that at lower displacements in Design-Basis Earthquake (DBE), force levels are close to a regular system while at highest levels of displacements in Maximum Considered Earthquake (MCE), the device hardens to make the substructure yield and limit deck's displacement.