Genetic Algorithms in Optimum Concrete Design

Engr. Alden Balili, my graduate thesis advisee did a research on the application of genetic algorithms (GA) in the optimum design of reinforced concrete (RC) space frames considering seismic provisions of the code. The process of GA and its application to the optimization of space frames is in the figure below. Initially, the sizes of the beams and columns of the space frame are randomly selected which becomes the initial population. These sizes are then used by a separate Finite Element Analysis program to determine the member forces which are required in the design of the members including the amount of steel reinforcements. A database of the beam and column sections is used in the design process. The provisions of the National Structural Code of the Philippines (2001) are incorporated in the fitness evaluation of the solution or individual to satisfy the strength and serviceability requirements. The GA procedures of selection, cross-over, mutation and leader reproduction are then applied to generate a new population of solutions. He conducted GA simulations to determine the behavior of the optimization procedure using the different GA procedures like binary vs gray coding, leader reproduction and mutation. Based on his simulations, a new type of leader reproduction called modified leader reproduction was proposed. It was found out that this feature improved the effectiveness and efficiency of the concrete optimization algorithm to acquire the optimal values.

A paper on this study will be presented at the IABSE 2009 Conference at Bangkok, Thailand on Sept. 9-11, 2009.