Abstract
The present paper deals with limit analysis of structures by genetic algorithms (GAs), which are simple GA (SGA), forking GA (fGA) and stochastic schemata exploiter (SSE). Although this problem can be expressed as a linear programming problem, it is formulated as a combinatorial optimization problem of elementary collapse modes in the present paper. A collapse mechanism can be coded as a partial tree graph of a connected graph, which expresses the relationship between elementary modes and common plastic hinges of two elementary modes. Example rigid frames of 2-bay 6-story buildings are analyzed by means of each GA with discussion on efficiency of these methods. As a result, it is illustrated that SSE is superior to the others.
