INFRASET Prestressed Concrete Poles Specified for Traffic Surveillance System

INFRASET Infrastructure Products has supplied over 500 fully prestressed concrete poles to support electronic surveillance and monitoring equipment for a freeway management system which is being implemented on most of Gauteng’s major routes by the national roads agency sSANRAL.

The surveillance equipment includes non-intrusive vehicle detectors and CCTV cameras, the latter being mounted together with a solar power generator on INFRASET’s poles.

All the equipment including fibre optic and electric cabling as well as a TV monitoring system at the National Monitoring Centre (NMC) in Midrand has been designed by ITS Engineers, which forms part of the ASTTI Consortium, responsible for the implementation of the project.

ITS project manager, André Dippenaar, says that INFRASET was chosen to supply the prestressed concrete poles because of its ability to manage quick turn-around times and its considerable design and manufacturing flexibility.

“Several design changes to the poles were made as the project unfolded and INFRASET was able to meet all the revised requirements. For instance, draw boxes were added to the top and bottom of the poles and the diameter of the internal conduit was increased from 20mm to 32mm without any problems,” said Dippenaar.

After making adjustment to the installation of the poles, the poles provided the required stability for the PTZ cameras used. The cameras have a range of 1,5km and are sensitive to vibrations resulting from passing traffic.

INFRASET product manager, Sizwe Mkhize, says that INFRASET is the only South African company which currently offers fully prestressed concrete poles.

“The poles supplied for this project were 13m long and were cast with Slimline I sections. This makes them considerably lighter without the loss of any strength properties. They offer other benefits, which include corrosion, fire and termite resistance, and the internal conduits makes cable theft extremely unlikely. Above all concrete poles are built to last and don’t require any maintenance during their lifespan which should easily exceed 100 years,” says Mkhize.

Worth over R100m, the traffic surveillance system is being implemented in four phases to monitor and improve traffic flows on Gauteng’s highways, which today have some of he highest traffic densities in the world. For example the N1 motorway between Johannesburg and Pretoria is the busiest in the Southern Hemisphere.

Phase one has been completed and covers the N1 between Johannesburg and Pretoria, a portion of the M1 in Johannesburg, the Geldenhuys Interchange on the N3, and the M2. Phase two, which is due for completion in July 2007, encompasses the N1 from Centurion to the N4 toll road and the N3 between Buccleuch and the Geldenhuys interchange. Other sections of Phase two include the N12 from the Diepkloof interchange to the Elandsfontein interchange, the highway between Gillooly’s interchange and Snake Road, part of the N17, the N3 up to Heidelberg Road, and the N1 from Buccleuch to the N1/N124 Potchefstroom split.

Over the longer-term the system could be extended along the N1 between Johannesburg and Cape Town.

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