Currie Reservoir – Continuous Caisson Wall

Currie Reservoir - Continuous Caisson Wall

Increased Safety: We Used Horizontal H-Piles

This project is a part of a large upgrade to the Currie Reservoir in southwest Calgary, Alberta. The project included the installation of a caisson wall as well as horizontal shoring and underpinning.

  • The purpose of the installation of the caisson wall was to provide support for the existing pump-house structure as the excavation was taking place between the pump-house and underground water tank.
  • The retaining wall was designed by J.R. Spronken & Associates Ltd. as a Cantilever Secant Pile Wall with a maximum excavation depth of 8.0m below grade.
  • The length of the shoring wall is approximately 48 linear meters with total exposed surface area of about 370 square meters.
  • The pile sizes used include 760mm soldier piles and 610mm filler piles. The overall scope of the work consisted of drilling 28 soldier piles and 30 filler piles.

The client also approached HCM with the request to provide horizontal shoring/underpinning at the bottom of the excavation in order to provide a safe working platform for the connection of a 900mm diameter pipe between the pump-house and water tank. HCM completed this task by pushing a series of H-piles horizontally, using a hydraulic jack which was set-up on a specially designed steel frame system attached to the caisson wall.

HCM Contractors completed this project ahead of schedule and to the complete satisfaction of both the client and the engineer.

Client: PCL Construction Management
Location: Calgary, Alberta

Currie Reservoir

Currie Reservoir

Horizontal Underpinning

This project consisted of an interlocking secant pile wall, combined with horizontal underpinning to accommodate a new connection to a pump house at the Currie reservoir in Calgary. The interlocking secant pile wall (caisson wall) allows for an accelerated construction schedule as it eliminates the ground loss that is present with the use of other styles of shoring. Where utilities were present, bracing supports were used to resist the lateral pressures present behind the filler piles.

Unique to this job was the installation of horizontal underpinning. The job required a new connection between the existing reservoir and pump house. To accomplish this task, a tunnel had to be created to accommodate the 900mm connecting water pipe. The underpinning provides support for the tunnel walls. The system worked well; after excavation, the resulting tunnel allowed safe access for the installation of the connection pipe to the pump house.

Because of the job’s proximity to the working water reservoir, special environmental precautions had to be taken in order to avoid contamination. Site-specific procedures were implemented; in instances where lubricating oils had to be used, for example when sliding the horizontal underpinning beams, food grade oils were used over hydrocarbon-based oils. As a result, the integrity of the water supply was maintained throughout the duration of the project.

Client: PCL
Location: Calgary, Alberta

St. Joseph’s Healthcare Redevelopment Project

St. Joseph's Healthcare Redevelopment Project

Unique Soil Conditions

The future location for this tower is located immediately adjacent to the emergency wing of the existing St. Joseph’s hospital in Hamilton, Ontario. HCM is a recognized shoring contractor that will take on many challenges relating to foundation design.

On this particular project, HCM took on the tasks of:

  • shotcrete shoring
  • caissons
  • micropiles
  • excavation
  • site services
  • demolition with the constraints of limited access and project complexity.

A portion of the work was to be performed indoors, which required special care towards the patients of the hospital and the HCM workers. The original design for this inside work included conventional pad footings dowelled in to existing caissons five feet below the finished floor. The soil conditions are unique on this project due to the fact that the site is situated at the bottom of the Niagara Escarpment where bedrock is on an incline. This increased the depth required for adequate bearing stratum, requiring the entire area to be excavated and the perimeter shored. To save costs to all parties involved, HCM proposed an alternate to the original design to provide hand-dug caisson caps around the existing caisson and column construction. Caissons were excavated to depths of 18 feet below the finished floor using reinforced compression rings and shotcrete shoring to reach adequate bedrock.

The above innovations were the optimal solution for this portion of work resulting in another successful hospital project by HCM on budget, on time.

Client: PCL
Location: Hamilton, Ontario