• Hatch Mott MacDonald and NORR Limited

    Northwest PATH Pedestrian Tunnel

    Toronto, Ontario, Canada

Project Summary

Toronto’s Northwest PATH tunnel, the world’s largest pedestrian tunnel network, connects more than 50 office towers through 27 kilometers of shopping arcades. The City of Toronto retained Hatch Mott MacDonald (HMM), in association with NORR, to extend the tunnel 200 meters into the financial district and build two surface access structures. The cut-and-cover tunnel maintained live utilities through a congested intersection, over a live subway, and adjacent to two major infrastructure projects.

The original referenced design proved to be unbuildable under existing conditions. InRoads software was vital to the design of complex tunnel alignments and selection of a preferred option. ProjectWise allowed all disciplines to collaborate throughout the iterative design process. The accurate and precise 3D modeling of spatial relationships between utilities and the tunnel structure was used for physical conflict resolution and utility relocations during the design and construction phases.

The 3D model effectively communicated the scale and complexity of utility relocations to affected stakeholders. Dynamic updating of design drawings throughout the design phase greatly reduced CAD resources required. Successful design and construction of the CAN $35 million PATH tunnel through one of the most utility- and transit-congested intersections will alleviate surface congestion in the city without disruption of critical utilities and daily activities.
Using a combination of MicroStation and InRoads, a detailed 3D model of existing and proposed conditions was developed to illustrate the project challenges and solutions. ProjectWise allowed all disciplines to collaborate and iterate their designs in a single location, increasing productivity through reduced file transfer times, simplified file sharing and unified archiving. The use of ProjectWise Explorer Mobile ensured that field staff had the most up-to-date documentation on site.
  • All utilities were maintained in service during construction, which was staged to maintain essential traffic corridors as well.
  • Bentley software generated the 3D models that illustrated the solutions for stakeholders to envision more clearly than 2D drawings
  • Careful modeling of the utilities and tunnel structure provided utility design and physical conflict resolution in both the design and construction phases.
  • “Bentley has always been at the forefront of CAD solutions, and we have always been extremely impressed with the ability of the Bentley tools to integrate seamlessly. We have hosted significant projects using our ProjectWise server with our JV partners and sub-consultants, and the structural analysis engineering tools and CAD design tools play a key role in our corporate engineering solutions.”

    Len Shields Hatch Mott MacDonald