Hydraulic Modelling and Pedestrian Hazard Assessment on Underground Access Stairs: The Paral·lel Metro Station Case Study in Barcelona

ABSTRACT Given the increasing flooding incidents in metro stations globally, underground space infrastructures must guarantee users' safety. This manuscript characterises the hydraulic behaviour of a flood‐prone access stairs of the Paral·lel Metro station in Barcelona. Using a real‐scale stairs model at the Technical University of Catalonia (UPC) and the Computational Fluid Dynamics (CFD) software FLOW‐3D. Hydraulic parameters; water velocity, and depth were analysed under different discharges. Human instability criteria, Momentum of Flow (MF) and Specific Force Per Unit Width ‘SFPUW’ (M0) indicated that the most hazardous zone was the lower part of the stairs. Sectorised analyses showed that specific locations like the walls and proximities to risers presented lower safety criteria values compared to the centre of the stairs and steps' borders. Also, the numerical model closely mirrored the aerated flow experimentally observed. These findings provide useful information for future research campaigns aiming to improve urban resilience to face underground evacuation of flooded stairs.