The Anchor Shoring Group of Companies was awarded the contract to design and install 55,000 ft2 of lagged shoring, 10,000 ft2 of caisson wall, 30,000 feet of driven HP piles, 8,000 ft2 of traffic decking, utility supports and 50 CFA piles at this site. A combination of pipe struts and regroutable tiebacks were installed to brace the shoring systems. 20,000 feet of regroutable tiebacks were installed with drill lengths of individual tiebacks up to 125 feet.
The excavation at this site was up to 50 feet in depth. Ground conditions and grade elevations varied considerably over the length of the station. As a result the equipment requirements and installation techniques were modified to suit the existing conditions. Liners were vibrated through the recent clay to provide a seal in the till below using an ICE 4450 vibro mounted on an LS 318 Linkbelt service crane. Drilling inside the liners was completed using a Haine drill rig mounted on an LS 208 Linkbelt crane. The high rotary table of the Haine drill was ideal for providing a working clearance above the various liners which were required for this work. A Watson 3000 track mounted drill rig was also used for drilling of the filler holes in the caisson wall and areas where liners were not required.
The Anchor Shoring Group of Companies proposed value engineering alternatives relating to the driven and CFA piles which were accepted by TTC and resulted in a significant saving for the owner.
Planning of the work and cooperation with other parties on a construction site are necessary to ensure the successful completion of any project. At this site it was particularly important due to the numerous phases and the substantial work required to be completed by other trades in conjunction with the shoring. These efforts were key elements in the successful and early completion of this project.