Finite element analysis of prestressed steel-concrete composite cellular beams

This study investigates the serviceability behaviour of externally prestressed steel concrete composite cellular beams. The effects of tendon layout, web opening geometry, steel cross section, span to depth ratio, and prestress level on the serviceability bending moment were evaluated. A cross-section equilibrium formulation based on the plastic stress block approach of ABNT NBR 8800 and EN 1994–1–1 was also assessed. A three-dimensional finite element model was developed in ABAQUS and validated against experimental results, with a mean experimental to numerical ratio of 0.993. A parametric study comprising 450 simulations considered eight prestressed tendon layouts, a non-prestressed reference, two opening ratios, three steel profiles, three span to depth ratios, and three prestressing levels. External prestressing increased the serviceability bending moment by 18.5–50.5% across the steel profiles, with draped layouts providing the largest gains. Sensitivity analysis identified the steel profile as the dominant parameter, with a relative influence of 62.6%, followed by tendon layout at 35.8%. The equilibrium formulation systematically overestimated the numerical results, with a mean ratio of 0.588. A linear calibrated expression and a pruned quadratic response surface were then developed using nine dimensionless predictors. The quadratic form reached a correlation coefficient of 0.932, with 83.9% of predictions within 10% and a mean numerical to predicted ratio of 1.000.