Design Optimization of Lattice Girders According to Member and Joint-Related Design Constraints

Abstract

This study concerns with the design optimization of geometrically nonlinear lattice girders. The novelty of this study comes from simultaneously using the member and joint related design constraints, which are borrowed from the provisions of API RP2A-LRFD specification and defined depending on both member and joint strengths. A multi-objective design optimization approach named ImpNSGAII, which was improved in way of integrating both a neural network implementation and an automatic generating lattice girder tool for the search mechanism of NSGAII, is utilized in this study. Hence, this study purposes to investigate how to vary the optimality quality depending on the presence of joint strength-related design constraints. Thus, it is demonstrated that the presence of the joint strengthrelated design constraints causes to a divergence in the construction cost of optimal designs. Consequently, it is proved that the ImpNSGAII has a higher capability of exploring a conceptual lattice girder configuration in order to obtain an optimal design satisfying the economy, load-resistance and serviceability-related design conditions at the same time.