Optimum design of grillage systems with the firefly algorithm optimization method

In this study, grillage systems are designed by means of a well-known meta-heuristic optimization method in the literature, called firefly algorithm, such that they have optimum profile sizes and minimum weight. Naming of the algorithm is derived from the fireflies, whose sense of movement is taken as a model in the development of the algorithm. Fireflies' being unisex and their attracting each other constitute the basis of the algorithm. The design algorithm considers the displacement and strength constraints that in generated as a result of the implementation of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Construction). Of the 272 different W-profiles provided in LRFD-AISC, the method of firefly algorithm selects the appropriate profile for transverse and longitudinal beams of the grillage system, such that the design limitations described in LRFD-AISC are satisfied and the weight of the system is reduced to minimum. The weight of each candidate design generated during the iteration process is calculated by considering the unit weight of each section, which constitutes the system. Design examples is aimed to demonstrate the efficiency of the algorithm presented.