Effect of Beam Spacing in The Harmony Search Based Optimum Design of Grillages

The spacing between the longitudinal and transverse beams of a grillage system has animportant effect in the minimum weight design of these systems. In this study this effect is investigated using an optimum design algorithm which is based on recently developedharmony search algorithm. The optimum design problem of a grillage system is formulatedimplementing LRFD-AISC (Load and Resistance Factor Design-American Institute of SteelConstruction) limitations. It is decided that W-Sections are to be adopted for the longitudinal and transverse beams of the grillage system. 169 W-Sections given in LRFD code are collected in a pool and the optimum design algorithm is expected to select the appropriate sections from this pool so that the weight of the grillage is the minimum and the design limitations implemented from the design code are satisfied. The solution of this discrete programming problem is determined by using the harmony search algorithm. This algorithm simulates jazz improvisation into a numerical optimization technique. Design example is presented to demonstrate the effect of beam spacing in the optimum design of grillage systems.