Optimal design of civil engineering structures using optimality criteria methods

This report presents an Optimality Criteria method for the optimal design of civil engineering structures subject to multiple behavioural constraints on element stresses and nodal displacements and also to constraints on design variables. The method makes use of a first order approximation for both deflection and stress constraints instead of the zero order approximation based on the concept of Fully Stressed Design used for stress constraints by the majority of Optimality Criteria approaches. The better approximation for stress constraints, introduced by considering the stress components as linear combinations of the generalized displacements, removes the difficulties arising from the use of stress ratios which, particularly for a well-known 10-bar planar truss, leads in many cases to a wrong design. [Continues.]