scholarly journals Torsional Vibration Control of a Structure using Fluid Viscous Dampers

2021 ◽  
Vol 1197 (1) ◽  
pp. 012046
Author(s):  
Lingala Ajay ◽  
M. Anil Kumar

Abstract Damping plays a major role in design of structures resistant to earthquakes. The damping reduces the effective of the structure when they are assigned to lateral loads by energy dissipation. The number of dampers is available and in use today. Most of the dampers usually isolate the super structure from the substructure, dividing them in order to hamper the flow of vibrations into the superstructure. This classification is termed as base isolation techniques. While, the rest of the damping techniques, dissipates the oncoming vibrations on the superstructure itself and minimizes the damage to the superstructure. In this present study, Fluid Viscous Dampers (FVD) are used extensively over types of dampers. The structure endures two load types, the vertical loads and the sidewise loads, and conveys to the foundation. In order to have earthquake resistant structures, FVD have been used. In the present study, Dissymmetric Buildings are analyzed with and without Fluid Viscous Dampers. The software ETABS 2016 was used. Using Time history analysis in ETABS software, the RC building is considered and the structure is evaluated and connect with and without FVD.

Base isolation is an effective way to protect large structures from earthquake damage. It is a costly approach, as the entire structure must be supported on elastomeric or sliding bearings. Viscous dampers distributed throughout an otherwise conventional structure can achieve the same result at a significantly lower cost. Dampers are used to resist lateral forces coming on the structure. Dampers are the energy dissipating devices which also resist displacement of Reinforced Concrete (RC) buildings during an earthquake. These dampers help the structure to reduce buckling of columns thereby increasing the stiffness of the structure. During earthquakes, multi-storeyed buildings get damaged and as a result, large deformation occurs. Dampers reduce vibration and deformation of structural elements during an earthquake. Retrofitting buildings with fluid viscous dampers (FVDs) can improve Interstorey drifts and floor accelerations. In the present study, an RC framed building is modelled and analysed under Southern Sumatra and Chile earthquakes to evaluate the performance of the structure and its elements with and without energy dissipators. For the study, a model (G+19) with and without energy dissipators is modelled in ETABS. The seismic force is applied based on the time history data of the models pertaining to Southern Sumatra and Chile Earthquake. Response Spectrum analysis has been carried out to find the lateral displacements, storey shear and Base shear for the model with and without dampers. The lateral displacement, storey drift, storey shear and Base shear are found to less for the model with Linear FVDs when compared to the model with Non-Linear FVDs and without FVDs.


Author(s):  
S. P. Kotecha

Damping performs essential function in format of earthquake resistant structures, which lower the change of the shape when they are subjected to lateral loads or earthquake. In the existing study fluid viscous dampers (FVD) are used to consider the response of RCC buildings on sloping ground. The important challenge of a structure is to endure the lateral loads and switch them to the foundation and to control the story displacement. In order to make structure earthquake resistant, (FVD) have been used. The building is modeled in ETAB 2018 and modeled with different location of FVD. After the study results show building with fluid viscous dampers (FVD) at diagonal bracing shows better performance.


2012 ◽  
Vol 234 ◽  
pp. 96-101 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis

In the present work we have analyzed a particular base isolation system for the seismic protection of a multi-storey reinforced concrete (RC) building. The viscous dampers and friction sliders are the devices adopted in parallel for realizing the base isolation system. The base isolation structure has been designed and verified according to European seismic code EC8 and by considering for the friction sliders the influence of the sliding velocity on the value of the friction coefficient. A dynamic nonlinear analysis for a three-dimensional base isolated structure has been performed. Recorded accelerograms for bi-directional ground motions have been used which comply with the requirements imposed by EC8 for the representation of a seismic action in a time history analysis. In this paper a comparative analysis is presented between the base isolated structure with the described hybrid base isolation system and the traditional fixed base structure.


Author(s):  
Harsh Joshi

Abstract: Due to sloping land and high seismically active zones, designing and construction of multistory buildings in hilly regions is always a challenge for structural engineers. This review paper focuses to establish a review study on the Possible Types of building frame configuration in the hilly region and he behavior of Such building frames under seismic loading conditions, and (3) The recent research and developments to make such frames less vulnerable to earthquakes. This paper concludes that the dynamics characteristics of such buildings are significantly different in both horizontal and vertical directions, resulting in the center of mass and center of stiffness having eccentricity at point of action and not vertically aligned for different floors. When such frames are subjected to lateral loads, due to eccentricity it generates torsion in the frame. Most of the studies agree that the buildings resting on slanting ground have higher displacement and base shear compared to buildings resting on plain ground and the shorter column attracts more forces and undergoes damage when subjected to earthquake. Keywords: Building frame configuration, Seismic behavior, Dynamic characteristics, Response spectrum analysis, time history analysis.


2016 ◽  
Vol 10 (12) ◽  
pp. 245
Author(s):  
Solmaz Yaghobzadeh

Explained ways to strengthen structures against lateral dynamic loads can be divided into two broad categories. The first part is the structural systems for controlling seismic displacement and second part is the use of applying systems of control forces. Response mechanism of structures using control systems are improved and greatly reduce the risks of damage caused by earthquakes.Today the use of these control systems in buildings have been increased and it’s important to reduce vibration of structures is felt more than ever. As well as to improve the dynamic behavior of nearby buildings, control systems can be installed between adjacent buildings as activated, semi-active and inactivated systems. The main purpose of this study is the use of control systems in two similar adjacent buildings to reduce the entire system response which will be the analytical study of the impact of viscous dampers to control system performance.In order to analysis of modeling to improve the dynamic behavior of different adjacent buildings connected with dampers, two models of the original sample will be examined in this article. All examples are different from each other and to elicit response analysis and time history software SAP 2000was used. According to the results the effect of fluid viscous dampers for tall buildings compared shorter building, is less. Also, these dampers for adjacent buildings with different heights than buildings with same height are more effective.


2013 ◽  
Vol 639-640 ◽  
pp. 896-900
Author(s):  
Ying Yuan ◽  
Ai Hong Zhou ◽  
Yan Li Gao

Different friction bearing ratios have effects on the base isolation property of parallel composite isolation system subjected to the seismic excitation. In order to deeply investigate how the friction bearing ratio affect the isolation property, the numerical simulation was carried out by the time-history analysis method, in which the seismic response of parallel composite isolation system with different friction bearing ratios under different acceleration peak values were calculated. Then, the effects of different friction bearing ratios on the base maximum shear coefficients and base maximum displacements; the hysteretic characteristics and nonlinear properties were analyzed and discussed. The results show that, for the parallel composite isolation system, friction bearing ratio is a key factor affecting the isolation property and the nonlinear properties are tightly related to the friction bearing ratio and acceleration peak values.


2021 ◽  
Vol 309 ◽  
pp. 01136
Author(s):  
Siripuram Vamshisheela ◽  
Atulkumar Manchalwar

In this work the performance of U-Shaped Steel Isolator is evaluated for a 5-story building subjected to seismic and blast vibrations. The structure is analysed using SAP 2000 software and a nonlinear time history analysis is carried out. The effectiveness of using base isolation is studied by comparing the structural responses of the building with isolator and without isolator and noticeable difference was observed. As the U-Shaped isolator absorbs the energy in all directions, it effectively controls the structural responses. In this study, the building is subjected to four different seismic and four different blast induced ground motions. It was observed that by the use of supplementary energy device there is reduction in top story acceleration, base shear and less deformation in the structure. This study concludes that the use of isolator has been effective in minimizing structural responses.


Structures are mainly subjected to various types of loading conditions such as dead loads, live loads and dynamic loads such as earthquake and wind loads etc. The earthquake creates vibration at the base of the structure. In modern seismic design, the damping devices are used to reduce the seismic energy and enable the control of the structural response of the structure. In the present study, the seismic behavior of a structure connected with and without Fluid Viscous Dampers (FVD) has been describes. The software ETABS 2016 is used to perform the modeling and analysis of G +10 storey building by considering seismic zone IV. For analysis IS codes have been referred. The response of the RCC building is evaluated using Push-over and Time history analyses. Fluid Viscous Dampers are suggested to the structure, to control the seismic response and increase the stiffness of the structure.


Author(s):  
C. S. Tsai ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen

The use of base isolation for enhancing the seismic resistibility has been proved as an efficiency way from experimental efforts and theoretical studies. It is usual to insert a flexible device in horizontal direction to permit the most relative deformation at this level. Because of the rigidity of the superstructure is much higher than that of the base isolator underneath the structure, therefore, the behavior of the superstructure can be idealized as a rigid body during earthquakes. In general, hundreds of degrees of freedom and a step-by-step time history analysis are the basic requisitions for calculating the seismic response of a base isolated structure under earthquakes. In order to develop a simple tool which can be easily adopted for calculating the sliding displacement and the shear force of the base isolator, an exact solution for predicting the seismic responses of base isolated structures has been derived in this study. The comparison between the experimental results conducted at National Center for Research on Earthquake Engineering (NCREE) in Taiwan and the analytical results obtained from the exact solution show that the exact formulation derived in this study can predict the seismic response of the base isolated structure with very good accuracy.


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