Grayston Pedestrian and Cycle Bridge


The Grayston Pedestrian and Cycle Bridge, previously also known as The Great Walk Bridge, forms part of a 5km dedicated path between Alexandra on the eastern and Sandton on the western side of the M1 motorway in Johannesburg. Proposals have been made by City of Johannesburg to adopt the official name Kopanang Bridge.

Structural design

The bridge is a cantilever spar cable-stayed bridge and is designed to fit snugly just north of the Grayston Drive interchange with M1 motorway. The straight central section of the bridge is 176m long and consists of three spans. The two short spans are 38 m long and cross the on and off ramps on the eastern and western sides respectively. The main span of the bridge is 100m long and consists of a single and continuous cable-stayed deck supported by a single 70m high inclined pylon on the western side and by a pier on the eastern side. The deck is suspended by means of nine cables extending diagonally from the pylon and attached to the deck along the median.
The pylon is inclined towards the west and is restrained by a double set of nine cables extending down to a pair of plinths at ground level.

Collapse during construction

On 14 October 2015 temporary works erected over the busy M1 motorway collapsed onto the passing traffic. Two people were killed and 19 were injured in the collapse which blocked both the north and southbound traffic.
At the time of the collapse very little permanent works had been executed by the contractor. Piling on the western side in the vicinity of the foundations for the pylon had been completed and on day of the collapse blinding concrete was being placed to the base of the pylon pile cap.
After the collapse the contractor adopted an alternative construction method which was analysed in December 2015.

Deaths during construction