BAUER Foundations Canada Inc. was contracted in 2019 by PCL Construction Management Inc. to construct a temporary shoring wall system for a new residential condominium project.
58 structural piles (10.5m to 12m below grade) and 172 filler piles (8.6m to 10.5m below grade) were drilled. Each structural pile had a shaft diameter of 880mm. Segmental casing lengths used to support the bore through the granular materials varied across the site to reflect encountered ground conditions.
In addition, timber lagging was installed between the structural piles in the upper 1.5m of the excavation to facilitate removal of the top section of the shoring beams.
Up to two rows of temporary tie-back anchors were also drilled using a KLEMM rig to provide lateral support for the shoring system. The drill lengths for the tie-back anchors ranged from 15m to 18m.
The soil conditions were 2m thick layer of fill, underlain by 2m thick layer of gravel, followed by a similarly thick layer of sand. Bedrock was reached at approximately 11m below grade. The groundwater level was at 4m below surface.
The piling works were carried out close to existing buildings as well as to an existing Light Rail Transit track. Therefore, some design elements had to be modified to account for these factors such as the final length and angle of the tie-back anchors to avoid encroachment into the LRT property.