Civil Engineering December 2021 | Vol 29 No 11

20 December 2021 Civil Engineering SANRAL SA I CE 2021 Nat i onal Awards Category: Techn i cal Excellence W here once there was a pristine mountainscape, there now cuts a six-lane highway through the UNESCO International Biosphere Reserve of the Magaliesberg. Some may be shocked by this change in the skyline, and many will be grateful for the improved connectivity it brings, but all would appreciate the exceptional care and ingenuity implemented by the project team to ensure the impact on the environment is minimised. The PWV Major Road Network was a visionary master plan developed in the mid- 1970s with the intent to secure transport corridors across South Africa’s most densely populated area of the PWV, now Gauteng. Today, many of these roads have been constructed and provide mobility across the country’s economic hub and its surrounds. Due to the reduction in infrastructure investment over the past decade, some of the PWV road links critical to support economic growth are long overdue for construction. The recent completion of a greenfields portion of the PWV3 link, providing improved connectivity from Johannesburg, Lanseria Airport and Pretoria West to the N4 West, Rustenburg and Sun City is, however, a major step forward. The road also forms part of the N4 Platinum Spatial Development Initiative that was launched in 1996 as a strategic corridor between Gauteng and neighbouring Botswana with the aim of unlocking economic and tourism potential. Zutari was appointed in 2008 as consultants to SANRAL for the design review and construction supervision of the PWV3 Pampoen Nek Section, as this project was earmarked for expansion before the 2010 FIFA World Cup. Despite not being implemented at the time, the project was resuscitated in 2016 and was completely redesigned using the latest digital design tools and technology. Known colloquially as the Pampoen Nek Highway, the new 7 km long multi- lane highway, with a construction value of R377 million, follows a historic route that crosses the mountainous Magaliesberg Nature Reserve close to Hartbeespoort. Traversing the Nek required major earthworks through a challenging geological environment with the cutting being 19.5 m deep and 185 m wide at its maximum, while fills reach heights of more than 18 m. The project also included the construction of two interchanges and the longest dedicated game underpass ever to be constructed in South Africa. DIGITAL INNOVATION The project was a showcase for use of digital tools during both the design and construction phase. State-of-the-art BIM modelling formed the basis of the new highway and structural design, allowing for different design scenarios to be easily developed and visualised through high quality 3D renderings and videos. These renderings were also effectively used to demonstrate to the client and interested/affected parties how different design options would mitigate the impact on the environment, enabling them to visualise what the final, rehabilitated route would look like. Zutari also used this project as a pilot to test the various ways in which drones can be used (legally) during construction to the benefit of a project. Drones greatly added value during the construction phase to monitor progress, assess quanti- ties and gain visibility of difficult to reach locations along the project route to assess the success of revegetation and the suc- cessful rehabilitation of cut slopes. ENVIRONMENTAL, COMMUNITY AND AESTHETIC CONSIDERATIONS This was a particularly sensitive project from both an environmental and cultural perspective and, after the declaration of the Magaliesberg as a UNESCO International Biopshere in 2015, the focus on the environment played an important part in the new design solution. From the onset, this was no ordinary project. During a heritage impact assess- ment undertaken in 2008, military struc- tures dating from the late 1800s, as well as a historic stone paved mule path from the same era were discovered. Though severely deteriorated, the structures were meticulously excavated, documented, and researched by archaeologists accredited HIGHLY COMMENDED Technical Excellence category (Sponsored by Maccaferri SA) KEY PLAYERS Client: SANRAL Consultant: Zutari Contractors: Aveng and Lubocon Civils Crossing the Magaliesberg – Pampoen Nek Highway The Pampoen Nek Highway that crosses the mountainous Magaliesberg