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      • Open Access Article

        1 - Performance Evaluation of Viscoelastic and Friction Passive Damping System in Steel Structures
        Mohammad Taghi Kazemia Hosein Hoseini
      • Open Access Article

        2 - Effect of Gap Length and Using Viscoelastic Damper on ReducingSeismic Pounding in Adjacent Low-Rise Concrete Buildings
        s.mehdi zahraei s.mohammad khatami
        Significant growth of buildings in different shapes and heights in urban areas and lack of attention to their dependence being adjacent to each other during earthquakes has increased devastating effects of seismic loads. Existing buildings have been designed and constru More
        Significant growth of buildings in different shapes and heights in urban areas and lack of attention to their dependence being adjacent to each other during earthquakes has increased devastating effects of seismic loads. Existing buildings have been designed and constructed separately against earthquakes. However, to pounding of adjacent buildings has been less paid attention. Since different buildings are designed independently thus their floor levels are not at the same height and probable sudden poundings during earthquakes can damage and collapse the weaker building. There are two kinds of such poundings: floor to floor and floor to column that 1st case is investigated in this research. In this paper, in order to determineand reduce the pounding forces between adjacent buildings, two 2 and 3-story RC buildings are considered in which floor to floor pounding is studied. To prevent or reduce pounding damage, the effect of gap distance between two adjacent buildings and using viscoelastic damper in their bracingon reducing seismic impact and related pounding are investigated. SAP2000 and ANSYS are used for numerical study.Analyses results show that using viscoelastic dampers and increasing distance between two buildings would reduce their lateral displacements and related pounding. For example, 3cm distance between two adjacent buildings would create 7 impacts while increasing the distance to 4.5cm would reduce the impacts to 2. Also, placement of viscoelastic dampers between building floors would control their lateral displacements and reduce the impacts to just one. Manuscript profile
      • Open Access Article

        3 - Investigation of the Effect of Soil Structure Interaction on the Response of Structures with Viscoelastic Damper under Different Damping
        masoud pourbaba saeid javaherzadeh fariba seyyedi mohammadi
        Using additional dampers for reducing input energy of structures is an effective way for dissipating input energy of structures. Including appropriate tools in dissipating the input energy of structures is viscoelastic damper. Generally, according to the structural anal More
        Using additional dampers for reducing input energy of structures is an effective way for dissipating input energy of structures. Including appropriate tools in dissipating the input energy of structures is viscoelastic damper. Generally, according to the structural analysis, the soil under structures is assumed to be rigid and the effect of soil structure interaction has been ignored. However, in reality, this soil is not rigid and the soil beneath the structures changes the dynamic specifications of structures and thus response of it. Structural response and damper performance depend on various components including type of earth movement and soil specifications. In this research, a few two-dimensional special concrete frames were examined. For frame modeling of additional damper, we used Kelvin method and for modeling of soil structure interaction effects with additional damper we used spring and damper equivalent method in the OpenSees app. Studied frames after rehabilitation with damper have been analyzed under dynamic nonlinear time history analysis. This analysis was done in three damping 5%, 10% and 15%. And at the end the results of soil-structure interaction impact with viscoelastic damper under different damping are studied. Manuscript profile
      • Open Access Article

        4 - Investigation of Nonlinear Seismic Behavior of High-rise Reinforced Concrete Buildings and their Improvement by Viscoelastic Dampers
        Faraz Kazemi ashkan khodabandehlou
        Owing to the destruction of high-rise buildings during recent earthquakes, the use of a structural system of reinforced concrete moment frame with viscoelastic damper causes a loss of seismic energy and consequently reduces lateral displacement. In this study a high-Ris More
        Owing to the destruction of high-rise buildings during recent earthquakes, the use of a structural system of reinforced concrete moment frame with viscoelastic damper causes a loss of seismic energy and consequently reduces lateral displacement. In this study a high-Rise, 20-Storey, three-dimensional reinforced concrete frame with 8 Models, of which 4 models with moment frame structural system and 4 models with moment frame + viscoelastic damping system in two directions of X, Y located in the high seismic zone (A=0.3g) on the soil type III is considered. The aim of the present study is to investigate the horizontal lateral displacement (absolute and relative) of the stories, the base shear of frames under gravity loads, and lateral loads of the earthquake.  In order to modeling the viscoelastic materials, the Kelvin-Voigt model and to determine damping ratio(ζ) of frames with viscoelastic damper, stiffness coefficient (Kv) and damping coefficient (Cv) of viscoelastic dampers, the modal strain energy method have been applied. For seismic analysis of models without and with dampers, dynamic analysis of nonlinear time history via direct integration and modal (FNA) methods have been utilized, respectively.  Geometric modeling of all frames was done using the SAP2000-V15 software. The results indicate that with increasing span length (model 2 compared to model 1 and model 4 compared to model 3) and increasing the height of stories (model 3 compared to model 1 and Model 4 compared to model 2), the maximum absolute lateral and relative displacement of stories, and base shear along with X, Y without and with viscoelastic damper have an increasing trend. Also, the maximum percentage increase of the mentioned models with damper compared to without damper along with X, Y has decreased Manuscript profile
      • Open Access Article

        5 - Evaluation of the Performance of Visco-elastic Dampers in Near-fault Earthquakes using Nonlinear Time-history Analysis
        Rasoul Sabe-ahd Kolsum Jafarzadeh Mohammad Ali Lotfollahi-Yaghin