Tunneling
New York City Subway
Project Description
The New York City Subway is one of the oldest public transportation systems in the world, with 468 stations in operation; 229 miles (369 km) of routes, translating into 656 miles (1,056 km) of revenue track; and a total of 842 miles (1,355 km) including nonrevenue trackage.
Sole - Source Supplier
In planning for more than 50 years, the 2nd Avenue subway line is now a becoming a reality. Sika has emerged as the only company able to act as sole - source supplier for the full range of waterproofing solutions - from concrete and shotcrete admixtures, to waterstops, to membrane systems and injection technology.
Tunnel and Shaft Waterproofing System
The waterproofing system, consisting of a specifically formulated PVC-P membrane for sealing underground structures against intruding groundwater and an additional geotextile, which is installed around the entire circumference of the tunnel, between shotcrete and the cast-inplace reinforced concrete lining. The external drainage system consisting of sidewall and invert drainage, shall be installed at 34th Street Station Cavern, and north and south interlocking caverns only as part of a ground water hydrostatic pressure relief system, which ties into ground water discharge system at this location.
Sectioning
Water barriers arranged to seal off individual membrane sections. Installed only at 34th Street Station and interlocking caverns area in conjunction with grouting pipes (weepholes) to create a system to maintain watertightness using repair by injection.
Weepholes
Three inch polyvinyl chloride (PVC) pipe are installed near water barrier intersections and invert to drain water in case of leakage in conjunction with Sectioning. These pipes are also used for repair in case of leakage by remedial grouting. In the tunnel invert, a protection layer (PVC-P membrane equal to the specified material and thickness) is required to protect the membrane waterproofing system from damage by other trades prior to the placing of the final lining.
Sika Products
1.200 million square feet
- Sikaplan® WP 1100-20 HL2 and
- Sikaplan® WP 1100-25 HL2