Widening and Strengthening of the Songpu Bridge

The old Songpu Bridge is a railway-highway combined steel truss bridge. Due to the continuously increased traffic pressure during the past decades, the Songpu Bridge needs to be widened and strengthened urgently. This paper presents key issues in the widening and reconstruction design of the old Songpu Bridge, including reinforcement of the truss, structural design of the upper and lower decks, connection details of the superstructure, transverse anti-overturning design, connecting methods between the renovated approach bridge and the old bridge and the seismic design of the renovated bridge as well. The experience and engineering practice will provide valuable references for other similar old bridges that also need retrofit and reconstruction.