In this paper, the development of optimal design method which is applicable to the practical design problems such as a steel building consisted with specified member sizes is studied.
The set of specified discrete design variables used in this study is composed of ninety-four H-Beam sections and it is divided into four groups (HA, HB, HC and HD) in accordance with member properties.
Two schemes are utilized for the structural optimization which must be in discrete form in order to have practical meanings.
The first scheme, which optimizes total structure with all constraints considered at once, finds the continuous optimum solution first using the Gradient Projection Method and, later, the discrete optimum solution in accordance with Pseudo-Discrete Algorithm.
In the Gradient Projection Method, the number of design variables can be reduced steeply by the means of the function of the design variables in each group.
The second scheme optimizes the total structure by the element optimization. In this method, the Stress-Ratio Method and the Sensitivity Analysis of the Gradient Projection Method are combined with some modifications.
This method can be easily programed for the practical structural design problems and retains the existing design steps for the use in optimal design programs.
