"I have worked on many assignments in the last 16 years, but no other venture has challenged me quite as much as the Robert Mugabe upgrade and extension," says Watze Hepkema, an engineer at Africon Namibia.
This N$110,75 million venture was requested just over two years ago by the City of Windhoek to alleviate traffic in Independence Avenue. The demanding project entailed the extension of Robert Mugabe Avenue with a dual carriageway road over a length of 1,4 km and the upgrade of the existing 1,4 km of single carriageway road to a dual carriageway. In addition to this, the road had to be re-aligned to meet a design speed of 80 km/h.
To achieve this objective, nearly 18 intersections had to be altered, four bridges had to be constructed and the Klein Windhoek River with a 1 in 50 year flood volume of 274 m3 per second had to be re-aligned over 0,9 km. The project required the expropriation of eight properties for the alignment of the road and the relocation of certain sports facilities. Based on the negotiations with schools it was further agreed that the team would construct a pedestrian bridge over the road to provide a safer access to sports facilities.
The realignment of Windhoek River was an especially challenging aspect during the project's completion. "We re-aligned the Klein Windhoek River with a 900 m long, 40 m wide canal with 2,5 m reno-mattress lined embankments, thereby making available a portion of the river and floodplain for the construction of the road," notes Hepkema. "The project was awarded to the Klein Windhoek Joint Venture, which included Africon Namibia, Steward Scott Namibia and Lund Consulting Engineers. We were responsible for the roadworks and project management, while Steward Scott was responsible for the structural works and Lund Consulting Engineers for the re-alignment of the Klein Windhoek River."
The Robert Mugabe Avenue route was another challenge and proved especially problematic due to erf boundary and existing road restrictions. "We altered the vertical alignment through the business and residential area substantially in order to meet the 80 km/h design speed criteria. This posed many challenges because of the high number of intersections and accesses that had to be considered," explains Hepkema.
The environmental impact assessment (EIA) and impact mitigation plan on the proposed route was done by Eco-plan. The plan stipulated that two new trees had to be planted for every indigenous plant that was uprooted during the project. It was further agreed that the Namibian Botanical Research Institute (NBRI) could remove aloes and other plants on the route before any construction could commence.
The design of the roadworks was done with the help of interactive infrastructure design software called Civil Designer. "It is so much easier to improve the alignments of the road according to requirements when you are working in Civil Designer. The program calculates the desired quantities quickly and accurately and it has definitely increased our confidence," notes Hepkema.
One of the conditions of the contract specified the use of small and medium sized contractors (SMMEs). "We commissioned Grinaker-LTA to train the SMMEs in various facets of contract management and tendering. Six of these SMMEs were then awarded sub-contracts and an SMME manager was also appointed under the contract to assist and train the SMMEs in the actual execution of their contracts. We used Civil Designer to design the traffic circle, which allowed Robert Mugabe Avenue to link up with Independence Avenue directly, thereby excluding the link with Mahatma Ghandi Avenue. The circle has an outside radius of 50 m," says Hepkema.
The project has taken many months of planning and project management and is likely to be finalised over the next three months.