Construction of Cawthra Sanitary Sewer and Watermain, Phase 2
Role: General Contractor
Project Delivery: Design-Bid-Build
Tunnel Equipment: AVN1200 and AVN1500 Microtunnel Boring Machines
Primary Support: HDPE Lined – AWWA C302 Concrete Pressure Pipe
Ground Conditions: Georgian Bay Formation Shale
This Contract is for the construction of approximately 435m of 1200 mm diameter and 1065m of 1500mm diameter sanitary sewer by tunnelling along Cawthra Road and Bloor Street including vertical shafts to accommodate tunnel construction in addition to 1400m of 300mm sanitary sewer and 1150m of 200mm/150mm/50 mm and 40m of 400mm watermain via open cut along Cawthra Road, Silver Creek Boulevard, Bloor Street, Schomberg Avenue, Glorene Court, Hyacinthe Boulevard, and Hassall Road. Additionally, this Contract includes the Cured in Place Pipe (CIPP) lining and patch lining, structural rehabilitation of select existing sanitary sewers and laterals. The Contract was also updated to include applying concrete protective lining (CPL) to 965m length of 1500mm diameter AWWA C302 concrete pressure pipe installed previously by Technicore under a separate contract to protect the sewer from hydrogen sulfide emissions leading to corrosion.
The Work includes, but is not limited to, the supply of all necessary labor, plant materials, watermain and sanitary installation, connections to existing sanitary sewers and watermains, all sanitary sewer and watermain appurtenances, connections to all sanitary services, replacement of water services, sawcutting and removal of asphalt pavement, all excavation and disposal of excavated material, protection of structures below and above ground, protection of utilities below and above ground, placing and compaction of bedding material, commissioning and testing of installed work, placing and jointing asphalt, CIPP spot/patch repairs of sewers, CIPP rehabilitation of laterals, sewer cleaning and Closed Circuit Television (CCTV), traffic control, site restoration to existing or better conditions, etc., complete as specified on drawings.
Technicore Underground self-performed the tunnels including setting up compounds, support and sinking of the shafts, tunnel construction, and risers’ connections installations. Technicore as a GC managed subcontractors to complete the rest of the scope which included open cut installation, Cured-in-place pipe (CIPP) rehabilitations, concrete protective linings, traffic signals and surface restorations. Technicore’s sister company, Ewing Fabricators manufactured the AWWA C302 pipe and concrete pressure pipe manholes for this project. Ewing also supported Technicore by fabricating shaft support steel ribs, tunnelling jacking stations, tunnel seals, etc.
Owner: Region of Peel
Start Date: October 2019
Completion Date: June 2021
Consultants: IBI Group
As per the Geotechnical Data Report (GDR): “Based on the Physiography of Southern Ontario (1984), the surficial geology of the project site is relatively consistent, typically consisting of Late Wisconsinan Age Halton Glacial Till of silty clay to silty sand texture. Within the creek valleys, surficial alluvial deposits of gravel, sand, silt and clay are present overlying the till or bedrock, often with high moisture content and some organic content. Ordovician shale interbedded with limestone and calcareous siltstone of the Georgian Bay Formation lies at 4 to 11m below existing ground surface.” Both tunnel drives are located within Georgian Bay Formation shale. The shafts were excavated within the overburden soils and shale.