12d Slashes Planning Time Tables in WA - Main Roads Western Australia

ClientMain Roads Western AustraliaLocationAustralia, WA
ConsultantMain Roads Western AustraliaContractorMike Darmody


Main Roads Western Australia has drastically cut its road planning and associated preliminary design timetables by using 4D Model software (later renamed 12d Model).

The Rural Planning and Strategies branch of Main Roads recently used 4D Model to complete the initial preliminary design of the 128 kilometre, Marble Bar to Woodie Woodie Road, via the Ripon Hills route. The design project took only four weeks as opposed to the 18 months required by a similar, earlier project.

Mike Darmody, Planning Co-ordinator for the Rural Planning and Strategies branch said 4D Model had been used on numerous preliminary design jobs since being introduced in 1992.

"It has culminated in this large road building task where 4D Model really came into its own," said Mr Darmody.


The Challenge

"When we were developing the Newman to Munjina Gorge section of the National Highway, which was approximately 150 kilometres long through very similar terrain to the Ripon Hills route, the planning and preliminary design phase took 18 months, utilising the best available technology at the time."

The Ripon Hills route had been a dormant road proposal for 10 years but was fast-tracked by the WA Government after intense lobbying by mining companies which have used the existing gravel road to transport minerals and fuel.

The road is regularly closed, due to flooding, for up to six weeks a year and is described as a maintenance nightmare.

The new road, currently budgeted at $32 million, will carry a potential of 550,000 tonnes of mining products per annum. It will also benefit tourist traffic that is expected to explore the area when the road opens.

"The job probably would normally take four years to complete, for that length of road through that type of terrain," said Mr Darmody. "But the urgency of the requirement means it has to be fast-tracked to a two-year time frame and completed by November 1997.


The Solution

Mr Darmody believes the user-friendly nature of 4D Model has enabled his branch to usher in new road planning and design techniques resulting in reduced project timetables.

"The need to prepare time consuming, detailed, final design drawings months in advance of road development projects in the remote areas of Western Australia, are gone. "The Ripon Hills project will be achieved using design and construct techniques that will basically enable us to design the road one day and build it the next . This process is an extension of how roads in the Pilbara and Kimberley regions were built in the past; they were surveyed the day before, drawn up and designed in the camp that night, and final construction levels were handed out to the foreman the following morning."

A road’s vertical design profile largely dictates a road’s construction costs so the ability to quickly recalculate vertical alignments enables 4D Model users to monitor project costs.

"We can achieve a lot with the road’s horizontal locations, such as trying to achieve a 110 kilometre per hour design speed," said Mr Darmody.

"But it is the impact this high speed design has on the road vertically that dictates the cost of the project. This is reflected in the depth of cuttings or heights of embankments and resulting road gradients. A tourist access road can get away with ten per cent gradients but a mining access route with high road train volumes can handle no more than five per cent over short haul distances.

"If there is a need to change any of the alignment on the Ripon Hills route, the user-friendly capability of 4D Model for on site applications is going to be advantageous. If, as construction of the road proceeds, the project engineer is confronted with adverse geology or drainage that was not originally anticipated, the road design can be adjusted on site. Associated changes in road earthwork quantities are also recorded."

The Result

Mr Darmody believes 4D Model will also assist with the planing of a future major realignment of the National Highway, North of Perth. The proposed route bypasses areas that have attracted people seeking alternate lifestyles away from Perth.

"4D Model cadastral lot boundaries as well as the topographical model. If a person’s lot is going to be impacted by a major road realignment we can call up the legal position of a person’s lot and superimpose the alignment on top of this lot. "Because we have the capability of moving the alignment around and adjusting our vertical profile at the same time, we can show the impact the road will have on the property.

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