BAUER Foundations Canada Inc. was contracted in 2019 by PCL Construc-tion Management Inc. to construct a temporary shoring wall system for a new residential condominium project called Minto Annex. The project was located in Calgary, Alberta.
The scope of work consisted of 58 structural piles drilled to depths ranging from 10.5m to 12m below grade, and 172 filler piles drilled to depths ranging from 8.6m to 10.5m below grade.
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 up-per 1.5m of the excavation to facilitate removal of the top section of the shor-ing beams.
Up to two rows of temporary tie-back anchors were also drilled by BAUER 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 sur-face.
The piling works were carried out in close proximity to existing buildings as well as to an existing Light Rail Transit (LRT) 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.
The project was completed safely, within specifications and quality targets, to the satisfaction of the Client.