AN EFFICIENT FRAMEWORK FOR OPTIMIZATION OF NONLINEAR STEEL TRUSSES WITH CONTINUOUS VARIABLES USING LIGHTGBM

Corrosion may cause uniform or localized deterioration to steel bridges, which could gradually diminish carrying capacity as the damage worsens.Carbon fiber reinforced polymer (CFRP) has immense promise due to its low weight and excellent durability, elasticity, and strength.This paper investigates the effectiveness of CFRP as a repair for corroded steel I-girder ends in terms of shear and end-bearing capacities.First, this study presents finite element validation of corrosion and CFRP modeling; based on the result, the setting and analysis process can be implemented in the case study.Then, the simulation of five cases of uniform corrosion involves a range of corrosion damage situations, encompassing corrosion heights, widths, and thickness loss.The stiffener, end web, and inner web simulate the corroded part.Finite element analysis (FEA) uses nonlinearity buckling analysis and assigns the Shell S4R element type steel.The constitutive isotropic elastic model is applied to steel, while CFRP utilizes an orthotropic lamina.The CFRP failure pattern uses the Hashin Damage Criterion model constitutive.Three layers are applied to each side of the model.Analysis shows CFRP in stiffener corroded area significantly increases remaining shear capacity by 0-11.8% for one side and 0-19% for both sides, in bearing capacity by 0-8.4% and 0-17.3%, respectively.Its efficacy in end-bearing is 0-6.3% in the end web, inner web, and combination areas.End web shear capacity increased slightly, while inner and combination web capacity decreased by 0-2% from the health model.