Rassal Arama Tekniği İle Betonarme Kirişlerin Farklı Beton Dayanımları İçin Optimizasyonu

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013İnşaat mühendisliğinde betonarme elemanların tasarımında mühendisin deneyimine göre tasarım yapılmaktadır. Ancak bu tasarımların maliyet açısından en ekonomik olduğu bilinmemektedir. Bu çalışmada betonarme sürekli kirişlerin tasarımı maliyet açısından en ekonomik olacak şekilde optimum olarak belirlenmektedir. Optimizasyon işlemi için bir rassal arama tekniği (RAT) geliştirilmiştir. Geliştirilen metotta tüm kritik kesitlerin ve donatıların optimum değerleri, TS500-Betonarme yapıların hesap ve yapım kuralları yönetmeliğine göre bulunmaktadır. Kesit tesirleri üç moment denklemlerine göre belirlenmiş ve elverişsiz yükleme durumları dikkate alınmıştır. Geliştirilen metot en uygun maliyetli tasarımın bulunmasında etkilidir

Metaheuristic approaches for optimum design of cantilever reinforced concrete retaining walls

An approach is presented for optimum design of cantilever reinforced concrete (RC) retaining wall via teaching-learning based optimization (TLBO) algorithm. The objective function of the optimization is to minimize total material cost including concrete and reinforcing steel bars of the cantilever retaining wall by considering overturning, sliding and bearing stabilities, bending moment and shear capacities and requirements for design and construction of reinforced concrete structures (TS 500/2000). TLBO algorithm is a simple algorithm without any special algorithm parameters. This innovative approach is providing an advantage to TLBO in terms of easily applying to the problem. The proposed method has been performed on numerical examples and the results are compared with previous approaches. Results show that, the methodology is feasible for obtaining the optimum design of RC cantilever retaining walls

Optimum design of reinforced concrete columns employing teaching-learning based optimization

In structural engineering, the design of reinforced concrete (RC) structures needs an initial de-sign for cross sectional dimensions. After these dimensions are defined, the design constraints and the required reinforcement bars are calculated. But the required reinforcement area is not exactly provided since the size of rebars are fixed. At the end of the design, the security measures are provided, but the designer has no idea for the optimization of the design in mean of economy. For that reason, a powerful search methodology can be programed by using metaheuristic algorithms. In this study, optimum design of reinforced concrete columns was investigated by using an education based metaheuristic algorithm called teaching-learning based optimization (TLBO). In the methodology, the slenderness of the columns is also taken into consideration by using a simple approach given in the ACI 318 design code. In this approach, the factored design flexural moments are defined according to the buckling load and axial load of columns. The design variables of the problem include cross section dimension of the column and the detailed reinforcement design and the optimization objective is the minimization the maximum material cost of the column. Differently from the other metaheuristic algorithms, the decision of the optimization type (global or local search) is not defined by using a probability parameter in TLBO. In optimization, two phases of TLBO; teacher (global search) and learner (local search) phases are consequently applied in search of best design variables. The proposed approach is effective for the structural optimization problem

Farklı Periyotlu Bitişik Yapılar İçin Optimum Kütle Sönümleyicisi Tasarımı

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bitişik yapıların bir birleri ile çarpışması sonucunda oluşan tepki kuvvetleri yapıların hasar görmesine veya göçmesine neden olmaktadır. Bu durumların oluşmaması için yapıların aralarında uygun derz boşluğu bırakılmalıdır, fakat uygulamada bu boşluk yeteri kadar bırakılmamaktadır. Sorun içeren bitişik yapıların, birbirlerine göre göreceli ötelenmeleri pasif kütle sönümleyicileri ile engellenebilir. Bu durumda kütle sönümleyicilerinin özellikleri bitişik yapılar için özelleştirilmiş bir yöntem ile optimize edilmelidir. Bu çalışmada, armoni araştırma algoritmasına göre hazırlanan yöntem ile, bitişik yapıların her ikisinin de üstünde bulunan kütle sönümleyicilerinin optimum değerleri aranmaktadır. Sayısal uygulamada farklı periyotlu bitişik yapılar ele alınmıştır. Sonuç olarak, optimum kütle sönümleyicileri gerekli olan derz aralığının azalmasında etkilidir. Anahtar kelimeler: Bitişik yapılar, Kütle sönümleyicileri, Optimizasyon, Armoni araştırma algoritması, Sismik etkiler, Yapısal kontrol

Teaching-learning based optimization for parameter estimation of double tuned mass dampers

The classical methods for parameter estimation of tuned mass dampers are well known simple formulations, but these formulations are only suitable for multiple degree of freedom structures by considering a single mode. If special range limitation of tuned mass dampers and inherent damping of the main structure are considered, the best way to estimate the parameters is to use a numerical method. The numerical method must have a good convergence and computation time. In that case, metaheuristic methods are effective on the problem. Generally, metaheuristic method is inspired from a process of life and it is formulated for several steps in order to reach an optimal goal. Differently from the single tuned mass dampers, double tuned mass dampers can be also used for the reduction of vibrations. In civil structures, earthquake excitation is a major source of vibrations. In this study, optimum double tuned mass dampers are investigated for seismic structures by using a wide range of earthquake records for global optimum. As an optimization algorithm, teaching learning based optimization is employed. In this algorithm, the teaching and learning phases of a class are modified for optimization problems. The optimization of double tuned mass damper is more challenging than the single ones since the number of design variable is doubled and the design constraint about the stroke of the both masses must be considered. The proposed method is compared with the existing approaches and the methodology is feasible for parameter estimation of double tuned mass dampers

Betonarme İstinat Duvarlarının Çiçeklerin Tozlaşma Algoritması İle Optimizasyonu

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bir mühendisin ana amacı güvenlik ve ekonomik koşulları sağlayan en iyi sonucu bulmaktır. Bundan dolayı, optimizasyon çeşitli tasarım değişkenleri ve kısıtlarının bulunduğu mühendislik problemlerinin tasarımında gereklidir. Optimizasyonda, doğal olaylardan ilham alan metasezgisel algoritmalar optimum çözümlerin bulunmasında oldukça etkilidir. Bu çalışmada, yakın zamanda geliştirilen ve çiçek açan bitkilerin tozlaşma sürecinden esinlenen çiçeklerin tozlaşma algoritması kullanılmıştır. Betonarme istinat duvarları boyut ve donatı değişkenleri için optimize edilmiştir. Ayrıca, optimizasyon problemi devrilme, kayma ve taban basıncı kontrollerini de içermektedir. Önerilen metot minimum maliyetli optimum tasarımın bulunmasında olasıdır.The main aim of an engineer is to find the best solution ensuring security and economical conditions. Thus, optimization is needed in design of engineering problems with various design variables and constraints. In optimization, the metaheuristic methods inspired by natural happenings are very effective on finding optimum solutions. In this study, recently developed flower pollination algorithm inspired by the pollination process of flowering plants is employed. Reinforced concrete retaining walls are optimized for dimension and reinforcement design variables. The optimization problem also considers turnover, slip and base stress controls of the retaining walls. The proposed method is feasible to find optimum design with the minimum cost

Total potential energy minimization method in structural analysis considering material nonlinearity

Minimum potential energy principle is the basis of the most of the well-known traditional techniques used in the structural analysis. This principle determines the equilibrium conditions of systems with reference to minimization of the sum of the total potential energy of the structure. In traditional applications, this methodology is formulized by using matrix operations. A methodology has been proposed in the last decades for structural analyses based on the idea of using metaheuristic algorithms to obtain minimum potential energy of the structural system instead of following this classical approach. This new method, called “Total Potential Optimization using Metaheuristic Algorithms (TPO/MA)”, has been applied in this paper to truss structures considering linear and nonlinear behavior of the structural material. The metaheuristic method used in this process is teaching-learning based optimization (TLBO) algorithm. The proposed technique is applied on numerical examples and results are compared with other techniques in order to test the efficiency of the proposed method. According to results obtained, TPO/MA method with TLBO algorithm is a feasible technique for the investigated problem

Aspect ratio factor for finite element method analysis of axially symmetric cylindrical shell walls

Finite Element Method (FEM) is one of the most commonly used numerical analysis method for the structural analysis. The axially symmetric cylindrical shell walls analysis can be made by using FEM or similarity of beams on elastic foundation. The Superposition Method (SPM) is a method developed for the analysis of beams and can be employed in the analysis of cylindrical shell walls. In the analyses using FEM, there are some assumptions and boundaries for preparing mathematical models. One of these boundaries for shell walls is aspect ratio. In this study, it is investigated, the aspect ratio factor for FEM analysis of axially symmetric cylindrical shell walls. For that reason the FEM analysis results are compared with the Superposition Method (SPM). In order to obtain exact solution of cylindrical shell walls, the effects of loadings is calculated and defined to the computer program, which is developed for SPM analysis by using Visual Basic programming language. According to analysis results, aspect ratio has a significantly effect on analysis results. Also, it is occurred minor difference in the FEM analysis results even if in case of obeying the rules. First published online: 10 Mar 201

Metaheuristic algorithms in optimum design of reinforced concrete beam by investigating strength of concrete

The locations of structural members can be provided according to architectural projects in the design of reinforced concrete (RC) structures. The design of dimensions is the subject of civil engineering, and these designs are done according to the experience of the designer by considering the regulation suggestions, but these dimensions and the required reinforcement plan may not be optimum. For that reason, the dimensions and detailed reinforcement design of RC structures can be found by using optimization methods. To reach optimum results, metaheuristic algorithms can be used. In this study, several metaheuristic algorithms such as harmony search, bat algorithm and teaching learning-based optimization are used in the design of several RC beams for cost minimization. The optimum results are presented for different strength of concrete. The results show that using high strength material for high flexural moment capacity has lower cost than low stretch concrete since doubly reinforced design is not an optimum choice. The results prove that a definite metaheuristic algorithm cannot be proposed for the best optimum design of an engineering problem. According to the investigation of compressive strength of concrete, it can be said that a low strength material are optimum for low flexural moment, while a high strength material may be the optimum one by the increase of the flexural moment as expected

Optimization of PID controller parameters for active control of single degree of freedom structures

In active control of structures, the parameters of controllers used application must be perfectly tuned. In that case, a good vibration reduction performance can be obtained without a stability problem. During the tuning process, the limit of control force and time delay of controller system must be considered for applicable design. In the study, the optimum parameters of Proportional-Derivative-Integral (PID) type controllers that are proportional gain (K), integral time (Ti) and derivative time (Td) were optimized by using teaching learning-based optimization (TLBO). TLBO is a metaheuristic algorithm imitating the teaching and learning phases of education in classroom. The optimization was done according to the responses of the structure under a directivity pulse of near fault ground motions. In the study, time delay was considered as 20 ms and the optimum parameters of PID controller for a single degree of freedom (SDOF) structural model was found for different control force limits. The performances and feasibility of the method were evaluated by using sets of near fault earthquake records