Mississauga's City Centre neighbourhood includes City Hall, Square One shopping centre and more than 30 residential towers. A new addition to the concentration of condominium buildings in the neighbourhood is The Conservatory Group's Widesuites Condominiums, located one block south of Burnhamthorpe Avenue on Hurontario Street and constructed with the aid of anchored shotcrete excavation support by Geo-Foundations.
Deep excavations in this area of Mississauga are particularly well suited to the anchored shotcrete method, because bedrock topography is more or less flat, the overburden is dense and cohesive, the depth of overburden is typically less than 7 metres and vertical cuts within the bedrock can stand unsupported indefinitely.
The Widesuites excavation resulted in over 2000 square metres of excavation face, but only half of this had to be supported, since the balance was sound rock. All of the overburden cuts at the south, west and east perimeter of the site were supported by mesh-reinforced shotcrete tied back with 26 mm, 517 MPa threadbar anchors at 1.8 m centre-to-centre spacing (vertical and horizontal). Two different support schemes were incorporated at the north perimeter of the site where the use of tie back anchors was not allowed. To support the neighbouring driveway, excavation and subsequent shotcrete facing application did not proceed until after soldier piles, walers and rakers were installed. To support the neighbouring parkade, whose perimeter strip footing was founded on rock, a series of cantilever soldier piles with rebar-reinforced shotcrete lagging were installed.
Upon completion of the below-grade portion of the tower superstructure in 2009, all excavation support work became redundant.