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Tuned mass dampers (TMDs) are vibration absorber devices that are used in all mechanical systems to reduce structural vibrations. In the present study, an investigation of the effect of inherent damping of the superstructure is employed with a TMD. The analysis is done for different mass ratios of TMD and superstructure. The TMD parameters such as frequency and damping ratio are optimized via a metaheuristic method called flower pollination algorithm to reduce a frequency domain response. Due to taking the frequency domain as an objective, the investigation covers all types of systems (civil structures or machine parts) and excitation (wind, disturbance, earthquake, etc.). [ABSTRACT FROM AUTHOR]

In the optimum design of reinforced concrete (RC) members, the design requirements and composite behavior of concrete and steel make the problem a nonlinear one that can be only solved via numerical iterations. In that case, the best option for these problems is to use a metaheuristic algorithm. In this study, a design variable that is the height of the RC members is investigated for the different maximum value cases, because the optimum design tends to maximize this value to increase the moment capacity of the member by directly increasing the length of the moment arm distance of the force acting from steel rebar having more cost than concrete. [ABSTRACT FROM AUTHOR]

In the present study, a metaheuristic algorithm called Jaya Algorithm (JA) was investigated for a modified version. JA is a parameter-free algorithm. In the investigation, a parameter is added to the algorithm to adjust the weight of the additional part that is summed with the existing solution. Generally, these algorithms are used in the optimum design; but these can be used for solution and analysis of engineering systems. The investigation is done by using total potential optimization to analyze truss structures. Different weight parameters are checked for analysis of a truss system. [ABSTRACT FROM AUTHOR]

Particle swarm optimization (PSO) is a classical metaheuristic algorithm. The initial form of PSO may not suitable for several optimization problems of structural engineering. A basic modification of PSO is the usage of an inertia function in order to adjust the contribution of existing values of the velocity. In several problems, the inertia function is necessary in order to keep the candidate possible solution in a possible range without an extreme increase of the velocity value. This situation is proved by employing PSO for a basic topology optimization of a truss structure. The problem is solved by using constant inertia functions from 0.1 to 1 with 0.1 increments. The inertia function is crucially effective in the performance, sensibility and computational. [ABSTRACT FROM AUTHOR]

In this study, the optimum design of reinforced concrete (RC) continuous beams was investigated for different values of live (L) and dead (D) load ratio. The design methodology considers the total material cost of the continuous beam as the objective function. A random search technique was employed. The methodology considers the different cases of live loading and the most unfavorable solution is taken into account. In that case, the amount of the live load is effective on the optimum design. As the numerical example, a two span continuous beam was investigated. During the investigation, the total amount of distributed loads is the same for the cases, but the ratio of L/D is different. According to the results, L/D ratio is effective on the optimum design. [ABSTRACT FROM AUTHOR]

Adjacent structures are under to risk of pounding. The pounding of the structures is the reason of the collapse. To prevent the pounding, a seismic gap needs to be provided. If this gap is short, the sway of the structures may be prevented. For this purpose, a vibration absorber system is proposed. The performance of the system is dependent on the perfect tuning of the absorber parameters and the investigation of the proposed system is done for pulse-like impulsive motions found in near fault excitations. Eight different combinations of the single degree of freedom structures were investigated as the numerical examples. Comparing to the recorded ground motions, the proposed absorber system is more effective on impulsive motions. [ABSTRACT FROM AUTHOR]

In civil engineering, optimization is an important issue in minimization of structural responses or production costs. In optimization methodologies, metaheuristic methods are effective in finding precise results. In this study, a new developed metaheuristic algorithm called Jaya Algorithm (JA) is applied to a basic structural optimization problem. In this problem, the dimensions of an I-beam are optimized for the minimization of the vertical deflection. The result of the numerical example was compared with the results existing in the literature. It is seen that the JA method is more favorable than the others as far as the computational effort is concerned. Also, the effect of population number was tested for the I-beam problem. [ABSTRACT FROM AUTHOR]

Jaya algorithm is a newly developed metaheuristic algorithm. It is a single phase algorithm, but effective to converge to the best solution and diverge to the worst solution in a single phase. It is not a parameter effected algorithm since it does not contain any specific parameter except the population number. This algorithm proposed for the structural engineering problem which is a retrofit application. The aim of the optimization is to find the best design of carbon fiber reinforced polymer strips in order to increase the shear capacity of reinforced concrete beam. The proposed algorithm was compared with the algorithm which were previously applied. As a conclusion, Jaya algorithm is a competitive one with the advantages of being an easy method. [ABSTRACT FROM AUTHOR]

As known, tuned mass dampers (TMDs) are added to mechanical systems in order to obtain a good vibration damping. The main aim is to reduce the maximum amplitude at the resonance state. In this study, a metaheuristic algorithm called harmony search employed for the optimum design of TMDs. As the optimization objective, the transfer function of the acceleration of the system with respect to ground acceleration was minimized. The numerical trails were conducted for 4 single degree of freedom systems and the results were compared with classical methods. As a conclusion, the proposed method is feasible and more effective than the other documented methods. [ABSTRACT FROM AUTHOR]

The aim of the paper is to investigate the optimum design of truss structures by considering different stress and displacement constraints. For that reason, the flower pollination algorithm based methodology was applied for sizing optimization of space truss structures. Flower pollination algorithm is a metaheuristic algorithm inspired by the pollination process of flowering plants. By the imitation of cross-pollination and self-pollination processes, the randomly generation of sizes of truss members are done in two ways and these two types of optimization are controlled with a switch probability. In the study, a 72 bar space truss structure was optimized by using five different cases of the constraint limits. According to the results, a linear relationship between the optimum structure weight and constraint limits was observed. [ABSTRACT FROM AUTHOR]

During earthquakes, adjacent structures may collide to each other because of insufficient seismic gap. By using tuned mass dampers (TMD), the sway of adjacent buildings be reduced and pounding of structures is prevented. In this case, TMDs must be tuned according to the properties of adjacent structures in order to reduce seismic gap (maximum difference of displacements). Also, adjacent structures with equal properties may collide because live-loads on structures is not constant. Change of live-load affects seismic behavior of structures. In this paper, TMDs for adjacent structures with equal properties are optimized by using harmony search algorithm. The approach is effective to reduce the value of seismic gap needed for protection of structures. [ABSTRACT FROM AUTHOR]

A random search technique (RST) is proposed for the optimum design of reinforced concrete (RC) beams with minimum material cost. Cross-sectional dimensions and reinforcement bars are optimized for different flexural moments and shear forces. The optimization of reinforcement bars includes number and diameter of longitudinal bars for flexural moments. Also, stirrup reinforcements are designed for shear forces. The optimization is performed according to design procedure given in ACI-318 (Building Code Requirements for Structural Concrete). The approach is effective for the detailed design of RC beams ensuring safety and application conditions. [ABSTRACT FROM AUTHOR]

A reinforced concrete (RC) frame structure was controlled with active tendons under the excitation of near-fault ground motions. Proportional Integral Derivative (PID) type controllers were used and the controller was tuned by using a numerical algorithm. In order to prevent brittle fracture of the structure, the aim of the control is to reduce maximum base shear force. The RC structure was investigated for different characteristic strengths of concrete and the approach is applicable for the structure with 14 MPa concrete strength or higher. [ABSTRACT FROM AUTHOR]

Metaheuristic algorithms imitate natural phenomena in order to solve optimization problems. These algorithms are effective on the optimization of structural dynamics problems including vibration control with tuned mass damper (TMD). In this paper, structural dynamics optimization problems were briefly reviewed. As an example, a TMD optimization problem was presented. Harmony Search (HS) algorithm was used to find optimum parameters of TMD mass, stiffness and damping coefficient. The optimization process was conducted to reduce structural displacements of a five story structure. The properties of the structure are the same for all stories except the third story mass. According to the analyses results, the TMD optimized with HS approach is effective to reduce all maximum story displacements. [ABSTRACT FROM AUTHOR]

In this study the optimum parameters of tuned mass dampers (TMD) are investigated under earthquake excitations. An optimization strategy was carried out by using the Harmony Search (HS) algorithm. HS is a metaheuristic method which is inspired from the nature of musical performances. In addition to the HS algorithm, the results of the optimization objective are compared with the results of the other documented method and the corresponding results are eliminated. In that case, the best optimum results are obtained. During the optimization, the optimum TMD parameters were searched for single degree of freedom (SDOF) structure models with different periods. The optimization was done for different earthquakes separately and the results were compared. [ABSTRACT FROM AUTHOR]

Under-constrained and unstable structures are those which are kinematically unstable. They may show large displacements even under very small forces contrarily to well-constrained stable structures. Under-constrained structures manifest themselves with insufficient boundary conditions. On the other hand, structures with missing members may become kinematically unstable under certain loadings. A common property of these structures is that the rank of their stiffness matrix, used in their analysis by classical methods, comes out to be zero, thus making impossible their analysis by these methods. Fortunately, application of the method Total Potential Optimization using Metaheuristic Algorithms (TPO/MA) makes the analysis of these structures very simple, with no extra difficulty as compared to the analysis of wellconstrained stable structures. Examples shown in this study are demonstrating this fact. [ABSTRACT FROM AUTHOR]