The first of the twelve 70 ton concrete beams which make up the bridge linking two sides of Port Elizabeth across the N2 freeway, have been put in place by the developers of the Baywest road network.
The double bridge was specifically designed to reduce construction time while ensuring maximum safety for the contractor and road users during the construction period. Basil Read, which was awarded the tender to construct the road network by the South African National Roads Agency Limited (SANRAL) last year, is set to complete the bridge - the first across the N2 in the region in more than a decade - in record time.
The faster build means N2 motorists will be inconvenienced for a third of the usual time - four months as opposed to up to 12 months using conventional building methods. According to AECOM engineer on the project, Gerrie Albertyn, all 12 of the 70 ton concrete beams which make up the bridge were precast in a controlled area, off-site.
This meant that all 12 beams could be laid six at a time, closing off each side of the N2 for just two months, said Albertyn. Usually, the concrete is cast "in-situ" on site, with scaffolding needed under the bridge to support the slab while it cured, resulting in each side of the N2 being closed for up to six months.
Added benefit
"The added benefit of this system is that the beams have been cast in a special yard set up for casting concrete in controlled conditions. In the past, casting all the concrete in-situ resulted in the work being exposed to the elements, which made it more difficult to achieve the tight tolerances," he said.
The project required absolute precision, said Albertyn. Each 70 ton beam could be out of position by no more than 10mm when laid on the bridge bearings.
With 230 employees working feverishly to complete most of the network in time for Baywest Mall's opening in March next year, it was all hands on deck, said Albertyn. He added that the network would reduce rush-hour traffic in the city's western suburbs.
"At the moment there is a lot of congestion around the Macro interchange along Samantha Way and Frikkie Kotze Drive. This network will give people a link onto the N2 and later up to Cape Road," said Albertyn.
Milestone welcomed
The extension of Walker Drive and the road circling Baywest Mall, as well as the two on-ramps and two off-ramps leading to and from the mall from the N2, were set for completion by next March. The connection to Cape Road - the first phase of the long-awaited Redhouse Chelsea arterial route - would be completed by October next year, said Albertyn.
Baywest MD, Gavin Blows, welcomed the milestone, saying that it prepared the area for the future growth of the city, in line with the municipality's 2020 vision. "This road network has been a long time coming and will help unlock economic growth in the city's western suburbs," said Blows. "It's a project which we are very excited about and which is being overseen by the top experts in the industry.
"This bridge represents a critical link between two sides of Port Elizabeth, and more importantly it points towards the start of exciting and much-needed economic growth in the city."