Railway Vertical Lift Bridge - Pamban Bridge

The new Pamban Bridge is a movable vertical lift bridge that will be constructed to replace the existing Pamban Bridge, an early twentieth century wrought iron bascule bridge.

The lift span is a single steel deck, simply supported half through structure carrying a double railway track. It comprises 2No main longitudinal arch truss girders supporting 16No cross girders. The main girder top chords are connected at 5No points in order to prevent the onset of compression buckling. The track is carried by 4No Rail bearers connected to the Cross Girders. Finally, the deck is fitted with diagonal members for lateral restraint. The bridge superstructure is lifted by a mechanism comprising cables, sheaves and counterweight, fixed on 2No steel 35.6 m high towers. The towers consist of twin piers, 18.3 m apart, provided with a diagonal strut in order to withstand the load effects arising from the wind and earthquake actions.

The foundation consists of RCC piles and a rigid pile cap over which both the lift span and the tower will be supported.