Topcon GPS lets Macmahon go stringless on major Perth freeway project

Topcon GPS systems are playing a key role for Macmahon Contractors in the stringless construction of Perth’s 4.5 km Mitchell Freeway extension, which serves the city’s rapidly growing northern suburbs. The project, which started in November 2006, and is due for completion in August, was well into the pavement construction works as of early 2008 – with the entire project constructed without the need for stringlines or pegging. These include two Millimetre GPS™ on a John Deere 770D and a grader for the pavement works, and a 3D indicate system on a Cat D7 dozer for bulk excavation and levelling. Additionally, a number of Hyperlite rover systems have been used for survey and grade checking throughout the project.