  An innovative strategy for the optimal design of planar frames able to resist
to seismic excitations is here proposed. The procedure is based on genetic
algorithms (GA) which are performed according to a nested structure suitable to
be implemented in parallel computing on several devices. In particular, this
solution foresees two nested genetic algorithms. The first one, named "External
GA", seeks, among a predefined list of profiles, the size of the structural
elements of the frame which correspond to the most performing solution
associated to the highest value of an appropriate fitness function. The latter
function takes into account, among other considerations, of the seismic safety
factor and the failure mode which are calculated by means of the second
algorithm, named "Internal GA". The details of the proposed procedure are
provided and applications to the seismic design of two frames of different size
are described.
