N3 upgrade provides opportunity for innovation

Work is now well underway on the upgrading of N3 Section 2 from Dardanelles (km 26.6) to Lynnfield Park (km 30.6), with GIBB appointed by Sanral to assist with the design and construction of four bridge widenings, a new ramp bridge and V-drains, among other responsibilities. Construction commenced in January 2021 with completion scheduled by May 2025.

For the project, GIBB is employing a host of new technologies and innovations, including a specialist traffic modelling software called Aimsun, new LED street lighting, and stronger and heavier road pavement material.

Innocent Magwa, bridge design engineer, GIBB, says accommodating heavy traffic volumes, land acquisition and issues around groundwater have been some of the key challenges. In addition, during the design stage, most of the existing structures did not have as-built drawings.

“We had to employ other means like conducting structural surveys and 3D scanning to establish the sizes, spans and the amount of existing reinforcement,” Magwa explains, adding that this information helped to determine the capacity of the existing structures, as well as any strengthening required due to increased loads.

Magwa says he’s proud of his involvement in the project and its progress to date. “I especially enjoyed the design aspect, as dealing with existing bridge widenings is quite complex and requires a lot of attention to detail.”

Currently, Magwa is involved in the implementation stage and the inspection of the reinforcement on the bridge sites.