FUZZY BASED OPTIMIZATION OF CONCRETE STRUCTURES BY USING GENETIC ALGORITHMS

The fuzzy optimum design of concrete structures under static loads as regards both serviceability and ultimate limit conditions is presented. The procedure is oriented to the optimal design of R.C. frames but it is also suitable for other kind of structures. Design variables include either the shape and the dimensions of the concrete cross-sections, or the amount and location of the reinforcement. These quantities are assumed as deterministic. However, additional fuzzy variables are considered to take the uncertainties involved in the basic properties of the materials into account. The objective of the design process is to minimize the structural cost of the system according to side and behavioral constraints. An optimal solution is achieved for several levels of uncertainties by using genetic algorithms. The structural analyses needed for the solution process are performed by means of a composite finite beam element able to take mechanical and geometrical non inearities into account. An application to the optimization of a R.C. frame shows the effectiveness of the procedure