12d Model helps to build Queensland's Smart Road - John Holland Construction/Barclay Mowlem Pty Ltd

ClientQld Dept of Transport and Main RoadsLocationAustralia, Qld
ConsultantJohn Holland/Barclay Mowlem JVContractorRobert Smith

Project Summary

One of the most heavily trafficked routes in Australia is the Pacific Highway between Brisbane and the Gold Coast. Traffic using that section of the Pacific Highway has increased more rapidly than on any other highway in Australia, quadrupling since the road was built in the 1960s.

The Challenge

To address the problem of the increasing strain of south-east Queensland’s transport infrastructure, the Queensland State Government has developed an Integrated Regional Transport Plan for the region.

Part of this plan is to upgrade the Pacific Highway to an eight and six-lane Motorway between Logan, just south of Brisbane, and Nerang, on Queensland’s Gold Coast. A Queensland Department of Main Roads project, it is the largest road project ever undertaken in Queensland and is to be completed by September 2000.

The Solution

For construction purposes, the 43km Motorway project has been divided into six sections with contracts awarded to a variety of engineering firms. The highest value contract - $120 million - was awarded as a joint venture to John Holland Construction/Barclay Mowlem Pty Ltd for eight lanes for the section Logan to Stapylton, a distance of 7.4km, due for completion in March 2000.

Integral to construction of this section of the Motorway, is the use by the John Holland/Barclay Mowlem Surveying Department of 4D Model (later renamed 12d Model) software.

Robert Smith, the surveyor primarily responsible for running the computing operations of the joint venture’s Surveying Department, has developed an application based on 4D Model which, he explained, "allows me to manipulate the huge amounts of data involved to create the individual layers which make up the road and extract various quantities out of it".

His application involves taking the initial output, received as design files and natural surface files, from Queensland Main Roads and, using 4D, to convert this data into what he describes as "useful 4D data sets". Robert then creates cross sections on various alignments and applies 4D Model’s boxing or template functions to create various layers which are then triangulated.

The volumes of various materials used in the different layers which comprise construction of a road - from the embankment layer through the various layers of gravel on top of that, to the paving and bitumen components - are then calculated in order to determine the quantity for payment purposes on completion of the work.

The design files are also used concurrently with traditional plans to aid the construction process. Macros are used to create files for “TP SETOUT” software, run by the field surveyors in their HP 200 palm top computers.

From data in the natural surface file and survey data collected by site surveyors, further 'layers', such as existing ground, existing underground services, are created in data sets to aid the construction process. This means potential clashes between the profiled string and services, such as telephone lines, electricity cables, gas lines and drainage and water pipes, are easy to detect. In a further step, an existing ground model is triangulated for future volume calculations.

Triangulation has options to calculate surface area, depth contours (isopachs) and the intersection of triangulations, and options for slope, aspect and viewshed analysis. Colour coding can be used for the slope and aspect analyses.

The Result

The advantage of using 4D Model, Robert says, is that in the manipulation of all the data the 'layering' steps entail, "4D lets us run unlimited data sets and points and it's very fast at running volumes".

He says 4D Model's boxing, template and volume computations have "made the job a lot easier and faster, and its interactive capabilities provide immediate feedback at every stage. It is also easy to use," he added.

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