Using SUE to reduce Delays and Disruptions on City of Toronto’s Yonge Street Project

As more and more municipalities look towards replacing aging infrastructure along key transportation corridors, one common goal is minimizing the interruption to traffic and business along those critical routes. This paper reviews the City of Toronto’s use of Subsurface Utility Engineering (SUE) services to manage this important issue for their Yonge Street Redevelopment Project. The City of Toronto is currently in the process of developing strategies for proactively replacing aging infrastructure throughout the City. One such project is the replacement of the existing watermains along Yonge Street from Eglinton Ave to Lawrence Ave. The existing watermains are being replaced with two 300 mm watermains. In addition to the watermains, there are plans for sewer chamber rehabilitation, sewer lining, boulevard reconstruction and road resurfacing within the project area. In order to minimize disruption along this critical corridor the City looked at methods of gathering utility information that could be used to help minimize or eliminate potential delays during construction. The City decided to complete a Subsurface Utility Engineering (SUE) investigation, in accordance with the CI/ASCE 38-02: Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data. One critical aspect for the City was to compile an inventory of all the existing storm and sanitary chambers to determine if any rehabilitation would be required. To facilitate the collection of this data TSH/TBE used an innovative new technology – zoom camera – to take a photo inventory of each manhole from above, eliminating the need for confined space entry. The zoom camera allowed TSH/TBE to photograph all areas of the chamber, as well as take video and photos up each of the sewers to look for obstructions. The authors will analyze how the scope of the investigation was developed to ensure the efficient gathering of the data. They will also discuss the techniques used for the investigation, and comment on the benefits and limitations of each technique based on the site specific conditions. The paper will outline the key and interesting findings of the investigation – including the identification of abandoned sewers and sewers that had been compromised by directional drilling. It will comment on how the information from the SUE investigation helped to identify issues that would have caused delays during construction.