optimum design of castellated beams: effect of composite action and semi-rigid connections

Castellated beams and composite action of beams are widely applicable methods to increase the capacity of the beams. semi-rigid connections can also redistribute internal moments in order to attain a better distribution. combination of these methods helps to optimize the cost of the beam. in this study, some metaheuristic algorithms consisting of the particle swarm optimization, colliding bodies optimization, and enhanced colliding bodies optimization are used for optimization of semirigid jointed composite castellated beams. profile section, cutting depth, cutting angle, holes spacing, number of filled end holes of the castellated beams and rigidity of connection are considered as the optimization variables. constraints include the construction, moment, shear, deflection and vibration limitations. effect of partial fixity and commercial cutting shape of a castellated beam for a practical range of beam spans and loading types are studied through three numerical examples. the efficiency of three meta-heuristic algorithms is compared.