Sanral’s project to improve National Route 7 between the Melkbos and the Atlantis intersections is one of the largest roads projects currently underway in Cape Town.
It also represents one the biggest contracts awarded to AfriSam in recent times, involving the supply of about 650,000 tons of layer works material and 750,000 tons of overburden over the 30-month project period, as well as some 15,000 m3 of readymix concrete for bridge construction at the two new interchanges.
The N7 connects the Western Cape to Namibia via the Vioolsdrif border post carrying large amounts of traffic in volumes that are steadily increasing. The section between the Melkbos and Atlantis intersections had become a notoriously high accident zone and one of SANRAL’s primary objectives in initiating this upgrade is to improve road safety by replacing dangerous intersections with grade-separated interchanges and closing all other access to the freeway.
The project, scheduled for completion in November 2014, will also increase road capacity by creating a divided freeway with a 120 km/hour design speed. The dual carriageways are 10,9m wide with a lane width of 3,7m. The road reserve is 60 metres wide.
On any given day, AfriSam delivers an average of 3,000 tons of material to the project site, and this is in addition to on-time deliveries to many other customers in the Western Cape. AfriSam’s contract with main contractor Haw & Inglis also requires it to maintain stock levels up to 10,000 tons of each type of layer works material to ensure that, in the event of a breakdown, these critical supplies will not be interrupted. AfriSam has also needed to factor in often lengthy delays en route to the project site caused by logjams at the N7 weighbridge.
“The Western Cape is a highly competitive market for us and to secure a contract of this size is a gratifying indication of the confidence Haw & Inglis has placed in AfriSam to support this project,” Bevan Cornelius, AfriSam territory manager for building construction material in the Western Cape, says. “We have a sound longstanding relationship with Haw & Inglis that has proved the extent of our services, infrastructure and value-added capabilities. Past contracts for this construction company include the N2 Settlers Way hospital bend upgrade and the N7 widening of Piekenierskloof Pass, both of which were major projects.
“Having secured this latest contract, we’re well-positioned in the Western Cape to field future projects on the N7, having fully demonstrated that we have the knowledge and experience to manage such strategic developments.”
Prior to commencement of the project, AfriSam worked alongside Haw & Inglis to develop durable readymix designs that complied with the specifications for construction of the interchange bridges. Mix testing was carried out by AfriSam’s technical laboratories in Cape Town, and test beams were cast using various mixes and sent for independent verification by the Engineering Department at the University of Cape Town to achieve durability criteria as specified. Test beam verification was initiated three months before the project began because the compressive strength characteristics of the concrete had to be validated over 28 days.
Since construction began in May 2012, AfriSam continues to provide regular back-to-back testing with Haw & Inglis’ on-site laboratory to ensure the specifications are maintained through this highly specialised project.
AfriSam operates a fleet of 40 readymix trucks in Cape Town, transporting this material from its five readymix plants in the area, including a newly established plant in the Saldanha Bay Industrial Development Zone, to customers across the Western Cape. Its aggregates are supplied from quarries in Durbanville and Malmesbury.