Abstract Manager

Demolishing a major piece of infrastructure can be as significant as constructing it.  Effective traffic management and work zone coordination is critical to ensure safety for all involved workers and roadway users.

As part of Metrolinx’s Scarborough Subway Extension project, a new subway station will be built adjacent to Scarborough Town Centre in Toronto. A post-tensioned bridge at the project site infrastructure needed to be demolished in order to create sufficient space for the new station. The removal of this bridge carrying a 6-lane arterial roadway was executed over 72 hours.

The Progress Avenue Bridge, constructed in 1984, was evaluated at each phase of the demolition to ensure each section, including the longitudinal and transverse post-tensioned cables, could be contained and removed safely. Traffic diversions and transit detours were coordinated with the municipal and provincial roadway authorities due to its proximity to a major highway, multiple bus operators due to its proximity to a major bus terminal, and adjacent property owners due to its proximity to the Town Centre commercial properties. Clear demarcation and separation of work zones were implemented to safeguard the public and prevent spectators from trespassing. Utility coordination took place with municipal and third party utility owners to protect services.

The result was a coordinated choreography of twelve excavators and 960 work hours to demolish and remove 3000 cubic metres of concrete, all implemented safely and with minimized environmental impact. The rubble was removed and recycled within this period and the roadway below was open to traffic once more at the end of the 72-hour closure.