Numerical investigation of non-corrodible bridge deck incorporating Y-shape GFRP stay-in-place structural formwork

This study numerically investigates and optimises a non-corrodible concrete bridge deck system incorporating pultruded Y-shaped glass fibre-reinforced polymer (GFRP) stay-in-place (SIP) formwork. A comprehensive 3D nonlinear finite-element (FE) model was developed in ABAQUS/CAE, calibrated using the concrete damage plasticity model (optimal dilation angle ψ = 42°), and used to conduct a detailed parametric study on the effects of concrete strength, stiffener spacing, and stiffener thickness. The results demonstrate that concrete strength has a negligible influence on stiffness and failure mode but affects capacity, with reductions from 34 MPa to 20 MPa lowering cracking and peak loads by 16% and 14%, respectively. Stiffener spacing directly governs damage mode and post-peak response; reducing spacing from 80 mm to 50 mm improved ductility and increased peak load by 6%, while increasing spacing to 110 mm reduced capacity by 5%, indicating that the 80 mm spacing is not only structurally effective but also a cost-efficient configuration. Stiffener’s thickness showed a plateauing effect on the peak strength, with a 25% reduction improved material efficiency at the expense of 7% lower capacity, whereas a 50% reduction triggered brittle collapse without further peak-load loss. These findings provide quantitative guidance for the design of durable, efficient GFRP SIP bridge decks to accelerate resilient bridge deck design.