Before the second underground mapping exercise for the Sydney Light Rail project, the project owners consulted ACIL Allen Consulting to conduct a research on the economic impact , which specified the need and the economic impact of having an accurate 3D map of the underground utilities. Based on Allen’s study and the importance realized of underground mapping, it took nearly one month for the contractors to cross-check each unidentified utility using new technologies such as Ground Penetrating Radar etc., of which some utility provider claimed few, but the majority of them were no longer in service. By way of geolocating the subsurface utility networks in the second phase, the stakeholders involved in the project were able to digitally map the surface and prepare accurate digital 3D maps based on the systemic surveys. The 3D models were created using the BIM principles to initiate the construction process and improve construction productivity.
Further, ARUP developed a GIS-based utility clash detection system, which presented an automated interaction of the proposed rail infrastructure with the existing subsurface utilities, helping the contractors to plan well-ahead their construction plan and process around the utility networks. The system incorporated inputs from over 100,000 individual underground utilities (in varied formats) bringing them together into a single usable and readable interface. This enabled stakeholders to make informed decisions and increase efficiency during construction.