Ph.D. Tezi Görüntüleme
In this study, cost optimization of short- and medium-span bridge superstructuresconsisting of precast, pretensioned prestressed concrete adjacent I-shaped beams is
realized. The study includes topological and shape optimization. Design variables are thenumber of beams on bridge cross section, dimensions of beam cross section and amount of
the prestressing steel. Flexible working stress and ultimate strength, shear working stressand ultimate strength, deflection, ductility limits and geometry constraints are considered
in this study. Constraints are calculated according to AASHTO Standard Specifications for Highway Bridges.Genetic algorithm is used in this study. Genetic algorithm can be adopted for complex problems easily. It uses discrete design variables and randomly selected initial solutions for evolutionary optimization. In this study, three different kinds of crossover, three different kinds of mutation and reproduction operators are considered. In the first chapter of the study, general information is given about kinds and
techniques of optimum design, prestressed concrete, prestressed concrete bridges, purpose and scope of the study. In the second chapter, designing of pretensioned prestressed concrete adjacent I-shaped bridge girders, expressing of optimum design problem, solving of this problem with genetic algorithm are explained. In addition, three numerical examples are designed with the developed program and the results of these designs are evaluated in this chapter. In the third chapter, conclusions of this study and suggestions forthe future studies are given. This chapter is followed by a list of references. In this study, it is demonstrated that genetic algorithm can be efficiently used in shape and topological optimum design of pretensioned prestressed concrete adjacent Ishaped bridge girders.
Key Words: Prestressed Concrete, Bridge Superstructure, Genetic Algorithm,
Topological and Shape Optimization, Optimum Design