Two frame structure optimisation problems are handled. Firstly, the constra
ined minimum-mass problem, for which both continuous and discrete cases wit
h ideal (without buckling effect and its own gravitational load) and real (
with buckling effect and its own gravitational load) models are solved with
several types of genetic algorithms. Results for the continuous case (idea
l model) are compared with referenced solutions of traditional optimisation
methods. From state of the art, the chosen strategies include a generation
al genetic algorithm, a steady-state genetic algorithm and the CHC algorith
m. Moreover, we suggest one elitist strategy linked to the non-dominated so
rting genetic algorithm (NSGA) to solve the multiobjective problem of minim
ising simultaneously the number of different cross-section types and the ma
ss with several constraints. (C) 2001 Elsevier Science B.V. All rights rese
rved.