On November 15, 2013, as part of the 86,000 square foot Georgetown South Project, Bridge Tite Group, an Approved Applicator of Bridge Preservation LLC. installed the BDM spray applied waterproofing for tunnels on the top of the Metrolinx Weston Tunnel, which travels under King Street carrying the GO tracks. This portion of the structure, along with the portion that travels under Church street, is owned by the City of Toronto and will be completed in the spring of 2014. Throughout the day of the installation, the average temperature was 48ºF. While many waterproofing membrane and primer systems have difficulty curing at lower temperatures, Bridge Preservation™ products will cure extremely quickly quickly, even at temperatures below freezing.
The concrete surfaces were prepared using abrasive blasting and prepared to SSPC-SP13/NACE No. 6 standards. Proper surface preparation is absolutely critical to the success of any waterproofing installation. Special care was taken by Bridge Tite Group to properly protect adjacent areas outside of the installation zone from potential overspray. After surface and site preparation were completed, Bridge Preservation™ Concrete Primer was installed. The primer system helps promote adhesion between the spray applied tunnel waterproofing membrane and the concrete. Even 48ºF, the primer was fully cured in less than one hour. After curing, BDM™ spray applied waterproofing for tunnels was installed to a thickness of 80 mils. An additional 40 mils of spray applied waterproofing with an aggregate broadcast was then installed. This Aggregated Top Coat promotes adhesion between the spray applied waterproofing for tunnels and HMA wear course, and also provides a temporary driving surface for up to two weeks.
The entire installation procedure was done in one day to the satisfaction of both the general contractor and representatives of Metrolinx and the City of Toronto. On November 19, 2013, the King Street roadway was reopened to traffic.
Fourth Photo Credit: GO Transit (http://www.gotransit.com/gts/en/project/weston.aspx)
Metrolinx & The City of Toronto
November 15, 2013
Construction for Grade Separation Weston Tunnel Phase 3
City of Toronto, Ontario, Canada