Optimal placement of braces for steel frames with semi-rigid joints by scatter search

A heuristic method called Scatter Search (SS) is applied to optimize the placement of braces for steel frames with semi-rigid joints. The standard SS is modified such that the hierarchical clustering is used for the update of the solutions needed to diversify the solution set. The nonlinear analysis called refined plastic hinge method is used for structural analysis. The nonlinear relations between rotations and bending moments of semi-rigid joints are modeled by the three-parameter models. Three design problems are formulated as combinatorial problems and solved by SS. Finally, the characteristics of the optimal solutions are discussed.