N2 KZN north coast upgrading will increase traffic capacity

A 14-metre wide swathe winds through eucalyptus plantations, sugar farms, hills and valleys as construction proceeds for a new 34km dual carriageway on the N2 between Mtunzini Toll Plaza and Empangeni on the KwaZulu-Natal North Coast.

The R946 million project is one of the biggest road infrastructure developments undertaken by the South African National Roads Agency (Sanral) in KwaZulu-Natal and is aimed at coping with the increased traffic volumes on one of the country's key arterial roads.

The upgrade of this section of the N2 commenced in March 2016 and is expected to last 37 months. The main contractor is Murray & Roberts Infrastructure with the monitoring of the works being performed by UWP Consulting.

The new two-lane northbound carriageway will include the construction of two major bridges over the Mlalazi and Mhlatuze Rivers. Four agricultural overpasses over the N2 will be lengthened; new bridges will be built at the R34 Empangeni/Richards Bay interchange and at the P537 Port Dunford underpass; two road over rail bridges will be constructed; and 16 major box culverts and numerous minor box culverts and other drainage structures will also be built. In addition, the height of two overpasses will be increased by jacking up the bridges.

The existing road will be repaired and strengthened to become the new southbound carriageway once complete.

This stretch of the N2 is on a declared toll road and, therefore, the income generated from the toll plazas on the N2 North will be utilised for funding this project.

Corn'e Roux, Sanral Eastern Region project manager, said the lane configuration of the existing single carriageway was amended in 2004 as an interim measure to provide for regular passing opportunities in an effort to alleviate driver frustration.

"Due to the growth in traffic, the current lane configuration became inadequate, resulting in delays experienced by the travelling public."

He said current traffic volumes on the N2 south of Empangeni exceeded 12 000 vehicles per day, with the highest traffic volumes occurring on the section between the eSikhawini and Empangeni interchanges.

A requirement of the brief for this mammoth project was the requirement for UWP Consulting to provide training to 10 Sanral project managers who are registered as candidate engineers.

This has included theoretical technical training on all aspects of road design, together with practical feedback on the actual design process being carried out on the route. Approximately 20 training sessions have been delivered during the design stage.

Last week (Thursday 8 September 2016), one of the bridges across the N2 was successfully raised during a delicate operation lasting three hours.

Bill Matthews, assistant resident engineer at UWP Consulting, explained the process.

He said two of the overpasses, once extended to accommodate the new north-bound carriageway, would be lower than the required limit, in terms of the clearance for traffic using the freeway.

This required the existing bridge to be lifted to a height that would tie in with the height of the new extension. This increment has been calculated at 500mm.

"The bridge deck over the current carriage way was jacked up to allow the piers to be extended. Thereafter the deck will be lowered into position on new bearing pads.

"The extension of the bridge can now be tied into the existing raised span at the required height above the road surface."

During the recent operation, four hydraulic jacks were used to lift the concrete span weighing approximately 200 tons.

"Two steel stub columns were inserted to support the bridge while the work on extending the piers is being carried out.

"The temporary steel support structure has been fixed in position to ensure that the bridge deck is secure during the construction.

"Once the first bridge is completed, the same process will be repeated on the second bridge," said Matthews.

All possible steps were taken to safeguard the public, road users and the construction team, during the lifting operation.

Meanwhile motorists are advised to take note of the construction work on the N2 between Mtunzini Toll Plaza and Empangeni T-junction and to be observant of the advance warning signs and speed reductions.