Originally built in 1927, the distinctive terracotta trim and red brick façade of the
Canadian Westinghouse Building in Toronto’s entertainment district is preserved in-situ
on a temporary frame supported by Case 1 micropiles also employed as vertical
members in a temporary excavation shoring system. Two street facing façades of this 6
storey heritage building were supported while the remainder was demolished to make
way for development, including two towers and five underground parking levels.
A large diameter soldier pile excavation support system was originally planned
around the site, however, proximity of a gas main and the preclusion of street closures
due to traffic congestion and light rail tracks, required a hybrid solution with small
diameter piles. The façade support frame was founded on two rows of vertical 356 mm
diameter piles, designed to act in tension and compression to suit wind loading on the
facade. The row of micropiles closest to site were also designed to withstand lateral
earth pressures and allow for potential bedrock expansion that is known to develop in
Toronto shales following excavation.
Subjects: temporary excavation, shoring system, lateral earth pressure
Author: Amanda Gordon, B.Eng., Michael Sousa, P.Eng. Brian Isherwood, MICE FCSCE P.Eng.
Publisher: ISM, DFI, ADSC