This is just one of a number of rail, river, road and utility services bridge structures that have been successfully completed by JG Afrika over the years.
A crack in the bridge pier widened after extreme flooding in early January 2017, resulting in the rotation of the pier and the settling of the deck. An assessment showed that failure was as a result of the erosion of the founding material below the old bridge’s spread footings.
The initial design entailed installing piles at the four corners of the failed pier, and a concrete beam with a lip would be cast between the piles to support the pillar. It was decided to rather dowel into the existing pier and to then cast it into the concrete beam when the damaged pier rotated further during the repairs.
The repairs were undertaken by G4 Civils as the main contractor and its sub-contractor, Civilcon.
Stefanutti Stocks Geotechnical undertook the piling and MBR the jacking of the bridge deck.
A large berm was used to divert the river before the installation of the propping and staging to support the bridge during the repairs.
Piling commenced once the bridge deck had been supported, and the work scope included the construction of piled protection structures in front of the piers to prevent their possible failure.
After their installation, Civilcon constructed the concrete beams to join the piles and support the pier.
MBR then jacked the bridge up by 100 mm to its original height, and the deck then supported on steel shims of varying heights to accommodate the angle of the pier.
This was followed by the repair of the crack and the reinstatement of the river bed to complete the repair works.