Trimble Alignment Planning greatly improves the collaboration between the engineering and environmental project teams and identified alignment construction cost savings of up to 23%

The QDMR planners demonstrated that there is significant benefit to applying the Trimble Alignment Planning system to highway projects, even where the corridor is very narrow and the terrain is flat to rolling. The study also demonstrated the ability to 'audit' and improve on alignments previously derived using the conventional approach to planning. Queensland Department of Main Roads (QDMR)

The Toowoomba Bypass will form part of the National Highway over the Great Dividing Range in South East Queensland and the corridor had been defined in the mid 1990s using traditional processes. The National Highway is a major freight route between the Australian States and Territories, and the existing Range crossing is currently approaching capacity, with a significant accident rate. Selection of a high capacity, safe crossing was vital to the Queensland and Australian freight industries.

QDMR commissioned the Trimble Alignment Planning system for the 22km Western Section of the Toowoomba Bypass Project to investigate the contribution that the system could make on a project that was already well advanced. The consultation and environmental analysis had already been completed, leaving only a small corridor for investigation - limited to ~300m along much of the project length. Alignments had already been developed using conventional planning approach with CADD, providing a benchmark against which to compare the Trimble Alignment Planning process and results. The corridor runs through flat to undulating terrain.

QDMR planners had already applied the Trimble Alignment Planning system on the Eastern Section of the Toowoomba Range Bypass Project, identifying alignment construction cost savings of up to 23%.

The middle 12km of the Western Section project needed to remain coordinated, if possible, with a proposed high speed rail alignment. The QDMR planners addressed this by breaking the corridor (and existing benchmark alignment) into 3 sections to enable investigation of alignment alternatives at different minimum horizontal radii. After optimisation of the sections, they were combined to enable a true comparison of the results achieved with Trimble Alignment Planning and with the conventional (CADD) approach. Note: Trimble Alignment Planning Version 5 now allows multiple geometric zones to be defined within a single project.

With the tight restrictions created by the urban no-go zones, there was not much room for movement in all three sections (alignments); nevertheless the Trimble Alignment Planning system was able to deliver an alignment construction cost saving of:

• • $26.56m, a reduction of 18% from the CADD derived alignment ($32.36m) in the Northern Alignment, (refer to figure 1);
  • $35.00m, a reduction of 25% from the CADD derived alignment ($46.57m) in the Centre Alignment (refer to figure 2); and
  • $9.313m, a reduction of 41% from the CADD derived alignment ($15.819m) in the Southern Alignment (refer to figure 3).

 

When the sections were combined, the project specific benefits achieved by the team included:

• • Improvement of the alignment quality, meeting all crossing, grade and radii constraints
  • Meeting all defined urban/community constraints
  • Cutting the alignment construction cost over the total length by 11%

 

About the Trimble Quantm Alignment Planning System

The Trimble Quantm Alignment Planning system supports road and rail planners through the complex process of selecting and generating 3D corridors and alignments. Its unique route optimization technology generates millions of alternative corridor alignments and returns a range of 10-50 best options for review by various stakeholders. In over 20,000 km of delivered alignments, the system has consistently enabled planners to reduce project planning time, substantially lower alignment construction cost, and deliver improved alignments that meet environmental, heritage, urban constraints, and design standards set by each project.