Fuzzy multi-objective genetic algorithm in determination of optimum mid connection location of off-centre bracing system

Optimization of steel structures based on conventional methods is not trivial, mostly when the optimization procedure deals with linguistic variables. Off-Centre Brace (OCB) system is a particular braced system that consists of three brace elements. The non straight diagonal member of this system introduce eccentricity to the system. It allows architects to have more opening. In designing this system, designers often use trial and error method to locate the connection point of the brace elements by considering various parameters which affect the design such as opening and frame dimensions, cross section areas of brace elements and the location of brace element connection. Hence, finding the best connection point to have maximum stiffness, minimum weight of brace elements and considering designers linguistic concept through conventional methods is not trivial. In this paper, a method based on multi-object genetic algorithm implemented by fuzzy logic in determining the best connection point is proposed. This proposed method is so useful for designers in designing this system and assist them in making decision on prioritizing between the frame stiffness and brace frame weight in their design by linguistic variables.