Stage-dependent sensitivity analysis of composite floor systems under Eurocode provisions

Abstract

Composite floor systems, which combine profiled steel decks and reinforced concrete slabs, are widely used in modern construction owing to their structural efficiency, construction speed, and material economy. However, the relative influence of key design parameters on structural performance remains insufficiently understood. This study investigates the effects of steel deck thickness, slab thickness, and concrete compressive strength to identify the governing parameters that control the composite floor behavior. A representative one-way composite floor system with CF60 profiled steel decking and a reinforced concrete topping was analyzed using a Eurocode-based analytical parametric approach. The analysis considered both the construction stage, in which the steel deck alone resisted the applied loads, and the composite stage, in which the hardened concrete slab and steel deck acted compositely. Parametric combinations were generated by varying deck thickness, slab depth, and concrete compressive strength, and structural performance was evaluated using demand–capacity ratios derived from Eurocode flexural resistance formulations. The results show that the composite floor behavior is primarily governed by construction-stage performance, with the steel deck thickness emerging as the dominant parameter. The slab thickness exhibited a stage-dependent influence, whereas the concrete compressive strength within the normal-strength range had only a minor effect. This study established a quantitative sensitivity hierarchy for geometric and material parameters under Eurocode design conditions. The analysis was limited to a code-based analytical framework without numerical or experimental validation.