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JG Afrika’s high-quality engineering services drive successful completion of road rehabilitation project

JG Afrika

JG Afrika provided design and construction supervision services for the successful rehabilitation of a 58,4 km section of the R399 on behalf of the Western Cape Government’s Department of Transport and Public Works.

Importantly, the R304,6-million construction programme created many employment opportunities for community members in the vicinity of the works, while serving as a fertile training ground for several local emerging contractors. This complements the vital role that the rehabilitated infrastructure is already playing in providing many road users with a safer and more efficient means of travelling between Piketberg and Velddrif.

“Our client wanted the project to create many employment and skills-transfer opportunities for communities in the area. More than 300 people from local communities were employed when construction peaked, while about 17 emerging contractors were trained by the main contractor during the 35 month construction phase,” Jürgen Gentz, an executive associate of JG Afrika, says.

Focus was on Main Roads 529 and 527, where collapsed mole tunnels in the layers had led to an undulating road surface. The already low road safety levels were also compounded by the very narrow carriageways.

Built in the 1960s, the roads now carry between 800 and 1 700 vehicles a day. This includes the many heavy commercial vehicles travelling between the Northern Cape and the Port of Saldanha.

The road has undergone periodic maintenance over the years and extensive repairs to the damaged layers have also been very costly.

JG Afrika was, therefore, briefed to design a long-term solution to mitigate future damage to the infrastructure, in addition to widening the existing carriageway.

Impact-compaction technology was deployed to first create a solid and uniform platform, before recycling and cement stabilising the road layers to a depth of 250 mm to prevent future tunnelling by moles. A 150 mm-thick crushed stone base layer was then placed and the final road surface completed with a 19 mm thick Cape Seal.

The new road comprises a new 9,8 m-wide carriageway, two 3,4 m-wide lanes, as well as two 0,9 m-wide surfaced shoulders and two 0,6 m-wide gravel roundings.

Platkloof River and Boesmans River bridges were also widened, with broadened sections cantilevered off the existing decks.

Other components of the work scope included lengthening existing pipe and box culverts; constructing additional pipe and box culvert crossings; and providing erosion protection at inlet and outlet structures of the culverts. Moreover, concrete-lined side drains were constructed in cuttings and earth side drains built.

Group Five commenced construction in November 2014.

One of the challenges was accommodating the many road users during construction, while ensuring a safe and productive site.

A ‘Stop/Go’ system with traffic signalling was implemented to allow construction to be undertaken in half-widths. A maximum of four half-width construction sections were permitted throughout the programme and the work area was limited to four kilometres with 4 km distances in between the successive work zones.

Gentz says that the contracting teams maintained an impressive safety track record and production rate throughout the entire duration of the project. This is despite the onerous conditions, including extremely confined working faces.

Another complexity was managing the multiple small, medium and micro enterprises working alongside the main contractor.

The road was officially opened to users by the Western Cape Minister of Transport and Public Works, Donald Grant, in October 2017.