Ph.D. Tezi Görüntüleme

Student:	Zekeriya AYDIN
Supervisor:	Prof. Dr. Yusuf AYVAZ
Department:	Civil Engineering
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University, Turkey

Title of the Thesis:	Optimum Design of Prestressed Concrete Bridge Girders Using Genetic Algorithm
Level:	Ph.D.
Acceptance Date:	19/7/2006
Number of Pages:	155
Registration Number:	di549

Summary:

In this study, cost optimization of short- and medium-span bridge superstructures

consisting of precast, pretensioned prestressed concrete adjacent I-shaped beams is

realized. The study includes topological and shape optimization. Design variables are the

number 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 stress

and 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 for

the 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