World Cup accelerates Cape interchange overhaul

The successful conclusion of its role in the upgrade project for the Department of Transport and Public Works and the Western Cape provincial government won HHO Africa the award in the category of Engineering Excellence for projects with a value greater than R250m in the Cesa Aon Engineering Excellence Awards.

Brian Dreyer, project director and financial director at HHO Africa, says the client wanted to boost the image of the host city for visitors and provide residents with an improved daily commute.

The interchange was built in the 1960s and was operating at full capacity, and during peak times it was not functioning correctly. Investigations determined that the interchange needed two new thirdlevel ramps, above the existing junction, to free up traffic flows.

"Given the time constraints, we had to phase in aspects of the upgrade and make sure that one of the ramps was fully functional in time for the World Cup.

"It was impossible to complete both of the enormous intersecting third-level ramps in the time available. Therefore, we focused on the one that would give the most benefit," says Dreyer.

HHO received the all-clear to start on the project in May 2007, and it had to get a contractor on site by early 2008 for the first ramp to be completed on time.

This meant that the HHO had to go through a fast-track process to establish all the design criteria and get them all approved.

"We convened a series of monthly meetings with the client with our full design team to present the next aspect that had to be approved.

"Usually, clients want to see the finished designs before they give approval but this was not possible in the time frame, so it required good support, a lot of confidence and full participation from the client for the process to work."

Dreyer says the design process usually takes as long, if not longer, than the construction phase; however, the interchange design had to be compressed into roughly a third of the usual period.

Another aspect of the time pressure on all parties was the tender process.

"The project went out to tender on good concepts but not absolute details. Therefore, the tender had to be flexible and we had to make sure a highly competent contractor was selected as they needed to adjust as the design evolved."

He says an advantage that flowed from this necessity was that the contractor was able to provide input into the process and suggest improvements that could be incorporated into the final design, particularly with regard to constructability.

He says HHO modelled the design on a computer so that everyone could see exactly what was envisaged. This element also helped in terms of improving the design's aesthetics as it allowed the designers to quickly and easily experiment with different column, piers and capping beam shapes.

"The entire project has now been finished and an adjacent project that was not part of the upgrade, namely the northern zone of the M5, has also been opened so people should now experience free flow in both southerly and northerly directions," says Dreyer.

Source: Business Day