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    Control of Reinforced Concrete Frame Structures via Active Tuned Mass Dampers
    (Springer-Verlag Singapore Pte Ltd, 2022) Kayabekir, Aylin Ece; Bekdas, Gebrail; Nigdeli, Sinan Melih
    In this paper, an active structural control method called active tuned mass dampers (ATMDs) was applied to reinforced concrete frame structures. ATMD is positioned on the top of the structure and uses a proportional integral derivative (PID) controller. Both damper and PID controller properties are optimized via an improved harmony search algorithm. During the optimization, the limit of control force, stroke capacity of ATMD and time-delay of the control system is considered. As the numerical example, a 15-story frame building is presented and the optimum ATMD is effective to reduce maximum displacement by 37.5% for critical excitation.
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    Öğe
    COST AND ENVIRONMENTAL FRIENDLY MULTI-OBJECTIVE OPTIMUM DESIGN OF REINFORCED CONCRETE COLUMNS
    (Scibulcom Ltd, 2022) Kayabekir, Aylin Ece; Bekdas, Gebrail; Nigdeli, Sinan Melih; Apak, Sudi
    In the construction industry, the aim is to construct low-profit structures that meet the demand of residents and safety measures, and also sustainability and environment-friendly measures need to be ensured in the production. Due to defined regulations in design codes to ensure stress capacity, ductility, and constructive needs, the optimum design problems are highly constrained which makes it a nonlinear one in defining the optimum design variables. In the present study, an optimisation methodology is presented via the use of a metaheuristic method called Harmony Search (HS) for reinforced concrete (RC) column members that having minimised cost and CO2 emission. The investigation is done for single objective cases of cost and CO2 emission together with multi-objective optimisation. According to the results, CO2 emission optimisation highly increases the cost of the design, while multi-objective cases lead to more low-profit results in the reduction of CO2 emission.
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    Öğe
    Design Optimization of a Hybrid Vibration Control System for Buildings
    (Mdpi, 2023) Salaas, Basel; Bekdas, Gebrail; Ibrahim, Yasser E.; Nigdeli, Sinan Melih; Ezzat, Mohamed; Nawar, Mahmoud; Kayabekir, Aylin Ece
    Control of high-rise structures under seismic excitations was investigated using a passive hybrid control system consisting of a base-isolation (BI) subsystem and a passive tuned liquid column damper (TLCD) system. Both of the systems were optimized considering using the other system in the same structure. An optimization method was developed, and a computer code was written based on dynamic analysis of the structure and metaheuristic optimization methods. Within the scope of the study, a general solution was found by using many earthquake records during the optimization process. Moreover, one of the most suitable and successful metaheuristic algorithms was used in this study. In addition, numerical simulations were performed on a benchmark high-rise building structure to investigate the effectiveness of the optimized hybrid control system in controlling the seismic response of the building. The performance of the base-isolated TLCD-controlled structure was examined when the TLCD was placed on the base floor by using a set of 44 recorded ground motions as base excitations. Based on the results obtained from this study, the use of a base-isolation subsystem decoupling the superstructure from the ground motions by lowering the structure's fundamental natural frequency reduces the structural responses of the building in most cases. The responses of the base-isolation subsystem were not too large since the parameters of the BI subsystem were optimized specifically for the investigated structure. Nevertheless, displacements of BI might exceed the maximum limit to undesirable values in some cases. The TLCD system appears to be quite effective in protecting the base-isolation subsystem by reducing its displacements to the maximum allowable limit or below when attached to it. Moreover, the proposed passive hybrid control system can effectively reduce the structural responses under seismic excitations.