Delivering large-scale construction projects requires project management to coordinate all the activities that are involved in the execution of the project, engineering and project implementation firm Hatch Goba reports.
“For example, a large amount of existing services – ranging from electricity and water infrastructure, to sewage facilities and communication cables – have to be identified and earmarked for either permanent or temporary relocation, while the project is still running,” says project lead Freek Serton.
Hatch Goba is the engineering and project management service provider to the R352-million Umgeni Interchange upgrade project that entails the easing of congestion along the N2 highway in Durban, KwaZulu-Natal.
The project involves the replacement of the current intersection with a free-flow directional four level systems interchange that accommodates the movement of 14 000 vehicles an hour in morning peak hour traffic and 16 000 vehicles an hour in afternoon peak hour traffic.
“Hatch Goba was appointed by the South African National Roads Agency in 2009 to complete the detail design and documentation for the upgrade of the interchange. The N2 and M19 is an area of major routes for passenger vehicles and heavy-duty freightliners, and it is essential not to disrupt any traffic along this national road,” explains Serton.
Construction officially began in March 2011 and is due for completion by the end of this year, Serton says, adding that one of the most important aspects of the upgrade project is reducing disruption to traffic during the construction phase.
He explains that to overcome this challenge two directional ramps have been constructed through a method of bridge-building known as incremental launch, where the entire bridge deck is built from one end of the structure. This replaces the standard segmental method, where the bridge is built one span at a time. Serton notes that this technology reduces space requirements and disruption to traffic.
“Through incremental launch technology, the sections of the bridge deck slide over special bearings, which are concrete blocks covered with stainless steel and reinforced elastomeric pads. This eliminates the need for building formwork to support the construction, thereby ensuring that construction can continue across the road without interfering with traffic,” Serton explains.
He says the first 232-m-long incrementally launched bridge was completed in January and the second 205-m-long bridge, launched at a height of 22 m above ground level, has also been completed. “The space restriction has proven to be challenging; however, our team of qualified engineers has been working to ensure that no major delays are encountered,” Serton adds.
In addition to the two incrementally launched bridges, the interchange upgrade project also involves the construction of seven segmentally constructed bridges totalling 581 m in length, as well as two conventional pedestrian bridges, measuring 65 m and 49 m respectively.
Construction also needs to accommodate existing services.
“The Umgeni road has been a major transport hub for many decades and a considerable amount of urban development has consequently taken place during this period. We have searched for and identified all the existing services. Although demanding and challenging, the relocation process of services is running smoothly, with all gas pipeline protection complete and 80% of all communication cables successfully relocated.
“Eighty-five per cent of all water services, as well as 90% of sewerage services, have also been successfully relocated. However, high-voltage infrastructure does not need to be relocated, while the relocation of medium-voltage electricity services is almost complete. The relocation of traffic signals and street lighting is the only service relocation that has yet to begin,” says Hatch Goba contracts engineer John McCall.
Serton believes that the expertise of the Hatch Goba project management team will lead to the successful completion of the Umgeni Interchange upgrade project according to specified timelines and within the allocated budget.
“This is one of the biggest projects of its kind undertaken in South Africa, which will bring world-class traffic services and infrastructure to the greater Durban area when it is completed. “I am confident that the newly upgraded Umgeni Interchange will set an international benchmark for similar projects to follow,” he concludes.