"Arroyo Las Piedras" Viaduct

The paper describes an innovative solution in composite steel-concrete bridges for High Speed Lines (HSL). The new design focuses on typical twin plate girder solutions, but modified to improve them with box girder capabilities. The double composite action used in hogging areas is made general along the whole length of the bridge to provide it with the torsional stiffness required for adequately controlling the dynamic response when railway stock eccentrically runs along a single track. The paper also describes additional aspects of interest, such as specific details to improve web resistance to concentrated loads, and some anti-seismic design linked aspects.