Seismic Responses of Multi-Storey Structures Equipped with Linear and Nonlinear Viscous Dampers: A Comparison Study (original) (raw)
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SEISMIC RESPONSE EVALUATION OF BUILDING WITH VISCOUS AND VISCOELASTIC DAMPERS
There is a great need for implementation of various earthquake mitigation techniques for effective control over the earthquake. The energy dissipation devices for dissipating earthquake energy needs to be studied in depth from view point of their efficiency in resisting earthquake forces. In this paper the performance of viscous and viscoelastic dampers are studied in detail. The seismic performances of these dampers are compared with normal bare frame building. Nonlinear modal time history analysis using Elcentro time history data was performed and parameters such as base shear, displacement time history at roof level, modal time period and maximum forces in outer and inner column are compared and presented. The modelling and analysis of building is done using SAP analysis package. The viscous and viscoelastic dampers are modeled by using nonlinear link element having property type dampers. The viscoelastic dampers are modeled as per Maxwell model of viscoelasticity. The properties of viscous dampers are calculated from shear storage modulus and shear loss modulus. The results obtained from analysis indicate efficient performance of viscous damper for resistance against maximum forces and control over displacement and base shear
Journal of Earthquake Engineering, 2020
A study focused on evaluating the influence of higher modes of vibration on the seismic design of buildings with viscous dampers is presented. In the first part of the study, expressions to estimate velocity and acceleration correction factors, applicable to Mexico City, are proposed. In the second part, a numerical evaluation of two buildings with different characteristics is presented. Results show that both higher modes and velocity correction factors contribute up to 52% in the maximum force developed in the damping system at the upper stories of the building. Acceleration correction factors and higher modes contribute at less 16% in the floor acceleration response.
SEISMIC ANALYSIS OF BUILDINGS USING FLUID VISCOUS DAMPER
Now a day's Earthquakes are happening in various parts of the earth. So buildings should be designed and constructed in such a manner that they will withstand the earthquakes. Non linear seismic assessment is a good tool in helping us to predict the seismic capacity. Many devices are used to improve the seismic capacity of the buildings. In order to reduce the negative impacts of earthquakes, different kinds of protective system have been adopted in the structures worldwide. Placement of fluid viscous damper is one of the techniques in which it absorbs the shock vibrations of the building which causes damage. The effect of damper on the seismic response of the RC structures is studied in this. Little attention has been paid to evaluating the influence of the number and placement of dampers on the dynamic response Three dimensional models are created using SAP2000. Time History analysis is carried out to study the effect of damper on the time period, base shear and acceleration in RC structures.
Response of Structures with Viscous Dampers Subjected to Large Earthquakes
Structures Congress 2013, 2013
Fluid Viscous dampers are added to building to protect its structural, nonstructural components, and contents. Dampers are designed to resist forces produced by the maximum considered earthquake. The efficacy of dampers in providing seismic protection and the code-prescribed methodology for design of these units have been well established and have been validated by the excellent performance of buildings with dampers in the past earthquakes. However, little data is available for buildings with viscous dampers subjected to large earthquakes. A multi-year research project is currently investigating such cases. Initial analyses revealed that the limit states of viscous dampers have a significant effect on the response of the building to which they are installed. Analytical model of steel buildings with viscous dampers, incorporating damper limit states, have been prepared and subjected to incremental dynamic analysis to determine the collapse performance. To date, analysis has shown that performance of the buildings with viscous dampers was acceptable when subjected to large earthquake. Furthermore, the use of factors of safety to delay the onset of reaching limit states was seen to be both beneficial and cost effective..
Earthquake Engineering & Structural Dynamics, 2014
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.
Seismic Response Evaluation of High-Rise Building with and Without Fluid Viscous Damper
American Journal of Civil Engineering
The major lateral load of the high structures is the earthquake load. In the high rise buildings, the structural response increases exponentially in response to earthquake load. Therefore, the damping has significant function in design of Earthquake Resistant High Structures, which can decrease the response of the structure when exposed to lateral loads. The energy produced by earthquake will be absorbed by these devices and the load acting on the main structure of the building will reduce significantly. The fluid viscous dampers are used to dissipate energy and lessen the response of reinforced concrete buildings. The main function of structure is to carry the lateral loads and transmit them well to the foundation. The lateral loads enjoined on the structures are dynamic in nature, which cause vibrations in the structure. In the current study, the responses of the structures having square plans with different cross-sections are analyzed by the software ETABS 2015 based on the consideration of Fluid Viscous Damper. The results of numerical examples show that fluid viscous damper (250) can reduce the response of the structures effectively, including the base shear of the buildings, and the structures with square columns performs perfect and have good earthquake resistant characteristics when compared to structures with rectangular columns regardless of the flooring plan.
Earthquake Engineering & Structural Dynamics, 2015
SummaryThis paper analyzes the influence of damper properties on the probabilistic seismic performance of building frames equipped with viscous dampers. In particular, a probabilistic methodology is employed to evaluate the influence of the damper nonlinearity, measured by the damper exponent, on the performance of structural and nonstructural components of building frames, as described by the response hazard curves of the relevant engineering demand parameters.The performance variations due to changes in the damper nonlinearity level are evaluated and highlighted by considering two realistic design scenarios and by comparing the results of a set of cases involving dampers with different exponents designed to provide the same deterministic performance. By this way, it is possible to evaluate the influence of the nonlinear response and of its dispersion on the demand hazard. It is shown that the damper nonlinearity level strongly affects the seismic performance and different trends a...
Earthquakes are one of the most destructive of natural hazards. Earthquake occurs due to sudden transient motion of the ground as a result of release of energy in a matter of few seconds. These recent events remind us of the vulnerability of our society to natural hazards. The protection of civil structures, including material content and human occupants is, without doubt, a worldwide priority. The challenge of structural engineers is to develop safer civil structures to better withstand these natural hazards. In the present study reinforced concrete moment resisting frame building of G+20 are considered. The building is considered to be located in the seismic zone (v) and intended for commercial purpose. Model-I Building without dampers, Model-II –Building with dampers. The building of G+20 has been modeled by providing with and without damper providing all parameters using S A P 2 0 0 0 software. Results show that using fluid viscous dampers to building can effectively reduce the building responses by selecting optimum damping coefficient i.e. when the building is connected to the fluid viscous dampers (FVD) can control both displacements and accelerations of the building. Further damper at appropriate locations can significantly reduce the earthquake response. Abstract-Earthquakes are one of the most destructive of natural hazards. Earthquake occurs due to sudden transient motion of the ground as a result of release of energy in a matter of few seconds. These recent events remind us of the vulnerability of our society to natural hazards. The protection of civil structures, including material content and human occupants is, without doubt, a worldwide priority. The challenge of structural engineers is to develop safer civil structures to better withstand these natural hazards. In the present study reinforced concrete moment resisting frame building of G+20 are considered. The building is considered to be located in the seismic zone (v) and intended for commercial purpose. Model-I Building without dampers, Model-II –Building with dampers. The building of G+20 has been modeled by providing with and without damper providing all parameters using S A P 2 0 0 0 software. Results show that using fluid viscous dampers to building can effectively reduce the building responses by selecting optimum damping coefficient i.e. when the building is connected to the fluid viscous dampers (FVD) can control both displacements and accelerations of the building. Further damper at appropriate locations can significantly reduce the earthquake response.
Nonlinear seismic analysis to evaluate the effectiveness of
The supplementary energy dissipation represents an efficient technique for the seismic protection of structural systems. In the last few decades several applications have been used in many countries, adopting damping systems with different characteristics, depending on both the arrangement of the damped braces and kind of damping device. However, for a widespread application of this technique, practical design procedures and simple numerical models are needed. In this paper, attention is focused on the modeling and nonlinear seismic analysis of framed structures equipped with friction, metallic yielding, viscoelastic and viscous dampers. A design procedure is proposed for proportioning damped braces in order to attain, for a specific level of seismic intensity, a designated performance level of the structure. A six-storey reinforced concrete (r.c.) framed building, designed in a medium-risk seismic region, is supposed to be retrofitted as in a high-risk seismic region. Two different criteria are followed for distributing the stiffness and strength properties of dissipative braces, over the whole at each storey, among the single braces. A numerical investigation is carried for studying the nonlinear dynamic behaviour of the designed structures. The results show that the proposed design procedure is effective and reliable.
Evaluating Effects of Viscous Dampers on optimizing Seismic Behavior of Structures
In the present paper, dampers position and optimizing their position at the height of the structure are studied. it investigates about viscous damper systems and their effects on seismic behavior of multistory structures and determines effects of damper system position on structure height using uniform distribution and SSSA methods. In this research, three 4, 8, 12storey steel structure frames were selected as the understudy models. The models were designed and analyzed based on available Codes to represent a sample of available structures. To evaluate effects of specific features of damper system, two 15% and 25% target values were considered for effective damping ratio of the damper system such that the results serve as representative of appropriate spectrum of conventional features of damper system. Following time history analyses on the models created under three earthquake records which were scaled according to spectrum design of Iran 2800 Code-3rd Ed., maximum response of relative displacement of stories was calculated for every position of the obtained damper.