The algorithm for nonlinear inelastic optimization of 3D steel frameworks under serviceability requirements

Abstract

An actual design of 3D steel frames structures must evaluate strength, stiffness and stability constraints (serviceability requirements) as well as nature of external loading. A design structure must satisfy optimality and safety criterions. An algorithm to solve optimization problem, incorporating all above described criterions, taking into account the geometrically non-linear structural behaviour, is presented for the 3D frame structures. The internal forces of each optimization cycle are obtaining in the previous optimization cycle via elastic-plastic nonlinear analysis procedure. Obtained forces are employing to obtain the new optimal design values. The nodal displacements are restricted during the optimization procedures to limited magnitudes in prescribed directions. The numerical experiment of the two-storey ed 3D steel frame designing by the standard steel profiles cross-section optimization problem was performed to show possibilities of suggesting solution algorithm.