Design

The NSW Roads and Traffic Authority (RTA) developed the concept design following the environmental impact statement (EIS) period. Detailed surveys, engineering and environmental investigations produced a highly accurate concept design that identified exactly where the highway could be constructed, what it will cost and what environmental and engineering concerns needed to be addressed. All of this information, along with standards of design, engineering and environmental safeguards required by RTA have been passed on to Baulderstone Hornibrook for implementation.

A team from consulting engineering firm, Maunsell, a recognised leader in transportation services, undertook the detailed design of the highway upgrade. The design process is currently being finalised allowing construction to take place.

Designing a world class highway involves integrating the aspects of safety within the constraints imposed from stormwater drainage, optimisation of earthworks, environmental impacts and construction costs. A risk assessment and ‘whole of life’ approach has to be adopted throughout the development of the design. Fast-track design and construction projects are difficult because they have to address these issues 'from the top down', but document the project 'from the bottom up'. That is, the design is based on producing a safe trafficable surface (at the top), but of course, construction must start at the ground surface (at the bottom).

The design is modelled in the computer, with the proposed road being superimposed on a model of the ground surface. This computer model is passed back to the construction surveyors who relate the model to actual on-site construction activities using electronic distance measuring equipment and sophisticated global positioning technology. Some of the engineering design parameters included in the design are: maximum grades, a design speed limit of 110kph, minimum horizontal radii of 1000metres, and a 40-year concrete pavement life.