Projects

One Bedford Condominium

Location: Toronto, Ontario
Duration: August 2007 - May 2009
Project Team: Isherwood Associates, H&R Construction, Toronto Transit Commissi

Project Details

Construction of a new condominium development was completed just south of the Bloor / Danforth subway line. Situated in the historic Annex district of Toronto, One Bedford is a prestigious 34 storey addition to this already booming area.

At 13 metres depth, the excavation was situated on a busy corner, adjacent to the Intercontinental Hotel, at Bloor Street.


Scope

Due to the proximity of the TTC subway tunnel, existing hotel and a very active parking lot, the site excavation was monitored carefully using electrolevels, inclinometers, precision survey targets and pile monitoring targets.

Instruments installed within TTC property included 20 electrolevels at critical joints in the tunnel boxes, and 40 precision survey targets inside the tunnel to verify any movements seen by the electrolevels which were read remotely.

Four deep monitoring points were affixed to the top of the tunnel to monitor any rotation into site while 8 inclinometers at key locations on the shoring piles, and 93 pile targets were tell-tales of the shoring deflection.

Ten precision survey targets installed to the east monitored any movements of the hotel during construction.

Readings were taken and reported on a weekly basis for the electrolevels, deep monitoring points, inclinometers and pile targets, while monthly readings were taken of the precision points on the hotel.


Noteworthy Aspects

Due to the close proximity of the subway tunnels, which were to remain active during construction, it was necessary to provide accurate and precise data of any movements recorded in a timely manner.

Due to a sequence of events, large movements resulted at the north shoring wall along the south side of the TTC tunnel. Readings were taken at an increased frequency to monitor these movements and to assess the performance of the emergency rakers which were installed to stabilize the wall movements while construction progressed.

By providing an in-depth monitoring program we were able to provide assurance in the stability of the shoring design as well as ensure the public’s safety.