Current - Issue

Lightweight beam-type structures require members with adequate axial strength, flexural stiffness, and buckling resistance while minimizing self-weight. Steel lattice trusses are efficient for such applications; however, compression chord members often become buckling and utilization-ratio governed under beam-type loading. Glass fiber epoxy composite wrapping provides a lightweight strengthening approach, though its structural benefits must be balanced against the additional composite weight. This study presents an integrated STAAD.Pro–MATLAB analytical framework for the lightweight optimization of glass woven fiber epoxy composite strengthened steel lattice trusses. STAAD.Pro is used to determine member axial forces. Equivalent steel–composite section formulations are then employed to evaluate transformed sectional properties, axial stress, Euler buckling capacity, utilization ratio (UR), total weight, and a dimensionless lightweight efficiency index. Solid circular rods, hollow circular pipes, and hollow square pipes were compared under identical loading and design conditions. The optimum configuration is a hollow circular pipe with 7 mm outer diameter, 0.5 mm steel wall thickness, and 0.5 mm composite wrapping, achieving a total weight of 1.633 kg and maximum UR of 0.794. Compared with the best feasible steel-only configuration, the optimized steel–composite truss reduces weight by 19.9% and improves lightweight efficiency by 37.9%. Taguchi and ANOVA analyses identified section size as the dominant design parameter, while member-wise UR mapping supported selective strengthening of highly stressed compression members for efficient composite utilization