A two-stage layout optimization procedure, consisting of reduction and
expansion processes, is presented. The object in developing this proc
edure is to use the advantages of both processes. In the reduction pro
cess, a reduced structure with a limited number of members and joints
is established by solving large scale idealized problems. An expansion
process is then employed, where members and joints are added to the i
nitial reduced structure. At this stage, relatively small problems are
solved, considering general variables, all relevant constraints and t
he real objective function.