Yazar "Aydin E." seçeneğine göre listele

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    Analysis of efficiency of passive dampers in multistorey buildings
    (Academic Press, 2019) Aydin E.; Öztürk B.; Dutkiewicz M.
    In this study, optimum design of viscous dampers under different mode behaviors are investigated for structures exposed to earthquakes. The structure is modeled as a shear frame and considered as linear. The upper and lower limit values of the dampers are defined as passive constraints, while the damping coefficients of the dampers placed in each storey are considered as the design variables. The use of these technological tools in construction has caused a serious cost increase. It is therefore important to use minimum of these elements. For this reason, the sum of the damping coefficients of the dampers is regarded as the objective function and is minimized as an indication of the capacities of the dampers placed in the building stories and thus their costs. It is well known that the addition of dampers to the structure increases the damping ratio of the structure. A new active constraint is included in the optimization problem as the target damping ratio. The equation required for the calculation of the value of the target damping ratio corresponding to any mode is also derived. The simple optimization problem is solved using three different optimization algorithms: Simulated Annealing, Nelder Mead and Differential Evolution algorithms. Optimum designs are found to minimize the cost function and provide all constraints. In the shown numerical example, the effect of the variation of the building period and the changes of the target damping ratio on the optimization is investigated. Furthermore, earthquake behavior of the structure corresponding to these optimum designs is investigated using El Centro Earthquake (NS) record and examined in terms of period and additional damping ratios of the maximum displacements to the floors. In addition, the proposed method finds the optimum damper distribution considering the first two modes. The proposed optimum damper design method is very simple and it is a method which reaches the optimum designs in different mode behaviors. As a result, it has been shown in the numerical examples that the optimum damper design can be changed according to the variations of the designer's constraints. © 2018 Elsevier Ltd
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    Optimum design of viscous dampers to prevent pounding of adjacent structures
    (Techno Press, 2019) Karabork T.; Aydin E.
    This study investigates a new optimal placement method for viscous dampers between structures in order to prevent pounding of adjacent structures with different dynamic characteristics under earthquake effects. A relative displacement spectrum is developed in two single degree of freedom system to reveal the critical period ratios for the most risky scenario of collision using El Centro earthquake record (NS). Three different types of viscous damper design, which are classical, stair and X-diagonal model, are considered to prevent pounding on two adjacent building models. The objective function is minimized under the upper and lower limits of the damping coefficient of the damper and a target modal damping ratio. A new algorithm including time history analyses and numerical optimization methods is proposed to find the optimal dampers placement. The proposed design method is tested on two 12-storey adjacent building models. The effects of the type of damper placement on structural models, the critical period ratios of adjacent structures, the permissible relative displacement limit, the mode behavior and the upper limit of damper are investigated in detail. The results of the analyzes show that the proposed method can be used as an effective means of finding the optimum amount and location of the dampers and eliminating the risk of pounding. © 2019 Techno-Press, Ltd.
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    The nonlinear effect of infill walls stiffness to prevent soft story collapse of RC structures
    (2012) Guney D.; Aydin E.
    Experimental or theoretical tests show that dramatically changes of infill area causes soft story mechanism. "Soft story" mechanism is the most frequent failure mode of reinforced concrete (R.C.) structures. This phenomenon is caused by the fact that the overall shear force applied to the building by an earthquake is higher at the base floor. If the lower story is not originally weakened, it is however there that infill are the most stressed, so that they fail first and create the weak story and finally leads collapse of structures. This kind of collapse was observed many times in Turkey caused by earthquake. The aim of this paper is to show the contribution of infill walls to the building response during earthquake. Different type of configuration of infill walls are modeled and analyzed by the Finite Element Method. These models also have soft story risk. The nonlinear force-displacement behavior is used for structural analysis. El Centro N-S component is used for time-history analysis. © Guney and Aydin.