Application of genetic algorithm to optimization of buckling restrained braces for seismic upgrading of existing structures

A systematic methodology is proposed for determining the optimal cross-sectional areas of buckling restrained braces used for the seismic upgrading of structures against severe earthquakes. Single-objective and multi-objective optimization problems are formulated. The objective for the former is cost and those for the latter are cost and damage. The constraint is the minimum structural performance required. A genetic algorithm is employed to solve both types of problem. Performance is estimated by conducting nonlinear dynamic analysis. A preliminary procedure based on static analysis is adopted to improve the search efficiency. Both approaches are applied to the strengthening of a multi-storey frame.