LRT Slope Protection at Retaining Wall

HC Matcon (HCM) and RWH Engineering (RWH) reacted quickly after being contacted to provide a design-build solution for a slope failure that occurred during the excavation for a new retaining wall at the Eglinton LRT project. The 14m (45’) high slope was approximately halfway excavated for a permanent block retaining wall when it a sudden slip failure occurred creating concern for the adjacent properties. RWH designed a slope retention system with soil nails and shotcrete facing to remediate the slope and allow for continued excavation. Using a TEI drill mounted on an excavator, HCM was able to reach the top of slope to install soil nails. Shotcrete was applied by a nozzleman in an elevated work platform. Once the exposed portion of the failed slope was stabilized, excavation was able to resume and HCM continued installing additional lifts of anchors and shotcrete to the base of the ﬁnished slope for a total protected area of 1250m2 (13,500 SF).

HCM and RWH provided an efﬁcient solution, adapting the slope protection design to assist with the durability of the permanent retaining wall. Real-time design changes were made onsite to accommodate additional area required after installation had already commenced, enabling the original retaining wall construction to resume as fast as possible.

Location: Toronto, ON

Customer: Metrolinx

Slope Remediation

HCM and RWH Engineering provided a design build solution to remediate a failing slope at a project located in Western Ontario.

Prior to HCM’s involvement, the site was excavated 7m into a silty clay at a 1:1 slope. HCM was contacted after the slope began to fail and large movements were seen. After RWH completed the design solution, HCM worked from a boom lift to install anchors with a TEI drill mounted on an excavator to stabilize the slope. HCM applied meshed shotcrete directly to the face of the slope and tied in the system by post-tensioning the anchors. Utilizing real-time engineering and quick execution, HCM was able to complete the installation without substantial ground loss, allowing for work onsite to be conducted safely.

HCM has applied shotcrete with tieback anchors as slope protection systems on many job sites with poor soils or tight sloping constraints. This project is an example of HCM’s and RWH’s ability to act quickly and adapt to changing site conditions to provide effective solutions.

Location: Coruuna, ON

Customer: Cope Construction and Contracting Inc.

Eglinton LRT – Cedarvale Station SEM and SOE

The Eglinton LRT Cedarvale Station required the new structure to pass below the existing TTC subway below grade. HC Matcon Inc. (HCM) was contracted by the Crosslinx group to perform segmental excavation method (SEM) and support of excavation (SOE) below the existing subway tunnel. HCM performed the detailed excavation and the installation of dry mix shotcrete in 6 galleries for the phased installation of structural needle beams to support the tunnel above.
HCM’s SEM work involved excavation in 1.1m sections, installation and stressing of temporary supports, and installation of accelerated ﬁbre-reinforced dry mix shotcrete for the walls and base slab. Due to strict movement tolerances of the tunnel above, a unique prestressed waler incorporated with shotcrete shoring was implemented. Special design and constructability considerations were coordinated with the designer to ensure safety during excavation. HCM installed a waler and tie-rod system that was prestressed from between the walers to achieve the deformed shape required by designers.
Due to HCM’s knowledge and experience with shotcrete and associated applications,
this unique project was executed successfully and to the satisfaction of the project
team.

Location: Toronto, ON

Customer: SKYGRiD Construction Inc.

Telus Sky tower

The Telus Sky tower will be the 3^rd tallest building in Calgary with the deepest basement excavation in western Canada. HCM Group took on the challenge of creating a shoring system suitable for the 30m excavation. RWH designed the shoring system with an 11m deep perched secant wall and shotcrete was used in the bedrock to stabilize the rest of the excavation. HCM contractors were responsible for the installation of the perched secant wall and the shotcrete.

The project was not without its challenges. These challenges included neighboring structures, the LRT system that ran adjacent to the site, existing Telus utilities and limited working space within the excavation. An extremely sensitive Telus duct bank ran adjacent to the excavation and the movement of the bank had to be kept to a minimum. RWH had to take this into consideration when designing the wall. The footprint of the excavation was only 2,100m². HCM contractors were able to work strategically with other sub-contractors to ensure work could be carried out seamlessly in the small area. RWH provided precision monitoring of the shoring, neighboring structures and the LRT line. Monitoring reports were provided twice a week until the excavation reached sound bedrock and it was then reduced to weekly.

HCM Group were able to use their experience with similar past projects to design and construct a shoring system that was suitable for the 30m excavation. The shoring moved 75% of what was originally predicted, proving it was more than adequate.

Client: Icon West Construction

Location: Calgary, Alberta

Upper House Condominiums

HCM completed the shoring for the eight storey Upper House Condominium project which required a 12m deep excavation for two levels of underground parking. A tied-back shoring system comprised of piles and lagging with caisson wall adjacent to an existing residence was installed.

Typical to developments in Toronto, there were encroachment restrictions on the south side of the site which only allowed for the tiebacks to extend a maximum of 6.2m to the neighbouring property line. To work within the limited space restrictions, RWH Engineering Inc. designed a system utilizing an upper row of double splayed anchors. Post-grouted strand anchors were installed to achieve the required load capacity in the soils. HCM with the supervision of RWH completed a load testing program to determine the optimal number of post-grout cycles required to meet the anchor design. Reducing the post-grout cycles resulted in schedule savings to the project.

Further, the shoring design was ﬁnite element modelled to allow for comparison against the monitoring results and ensure the shoring performed adequately throughout the construction.

HCM and RWH worked together to produce a design-build shoring re-design which was tailored to the speciﬁc requirements of the project and resulted in cost and schedule savings.

Location: Toronto, ON

Customer: SKYGRiD Construction Inc.

Sage Condominiums: Phase II

The construction of the new Sage Condominium required a shoring system that could facilitate the 10 meter foundation depth while working within encroachment restrictions. RWH Engineering Inc. (RWH), an HC Group company, was responsible for the design and provided precision monitoring throughout the duration of the project.

This project was innovatively designed to meet the needs of the owner. Despite the deep excavation and high building surcharge, RWH created an efficient shoring system that utilized only one level of pipe rakers. The use of bypass shotcrete over a caisson wall system advanced the project schedule as vertical drilling time was significantly reduced, allowing excavation to begin sooner. Shotcrete lagging has a smaller environmental footprint than timber lagging and eliminates the issue of wood rot next to existing buildings.

Client: IN8 Developments
Location: Waterloo, Ontario

The innovative design along with proactive construction management by HCM was the key to meeting project milestones. The small site coupled with the large structural members required well planned material deliveries, site organization, and crew management.

The ability to work together to meet special requirements on any project is a strength of the HCM/RWH team.

K2 Condominiums

This development on King Street in Waterloo required approximately 15,000 SF of shoring for two levels of underground parking. RWH Engineering Inc. (RWH) designed a piles and lagging shoring system with rakers to reach depths up to 9 meters. Wet fine sands required careful excavation and lagging in small lifts to ensure no ground loss occurred. High surcharges imposed by surrounding buildings required the rakers to be jacked in order to lock in the design load to minimize shoring movement.

Due to HCM’s efficient construction and project management, this project finished on time and on budget

Client: U.I.D. Developments Inc.
Location: Waterloo, Ontario

65 Lillian Street Condominium Building

Work on this jobsite included the excavation support system for a new condominium building located on 65 Lillian Street in Toronto, Ontario. HC Matcon used soldier piles and shotcrete lagging shoring (SPLS) with soil nails to support the excavation of an approximately 30-foot deep underground parking garage.

One challenge of this project was the close proximity of the excavation to the property line of the adjacent residential buildings. The consultant’s design included a caisson wall for this part of the system. HC Matcon proposed an alternative to save the owner and general contractor money, schedule time, and square footage of finished building by applying an equivalent system of shotcrete shoring and soil nails. This system will also act as a one-sided form for foundation walls.

During this project, there were some unforeseen obstacles for the shoring installation that required avoidance.

Utilities were found between the shoring system and the adjacent existing building footings to be demolished. HC Matcon was able to modify the pile design to support these utilities during demolition.

Other concrete obstructions were avoided by using an alternative pipe pile design to satisfy property line constraints, a perched walkway for the access of neighboring houses, and to facilitate the demolition of the existing parking garage.

HC Matcon will take on many challenges related to shoring and foundation design while keeping the interests of the general contractor and owner in mind.

Client: Lewis Build Corporation
Location: Toronto, Ontario

Twinning of the West Trunk Sanitary Sewer

Twinning Of The West Trunk Sanitary Sewer

This project includes the installation of a deep trunk sanitary sewer within bedrock under Erin Mills Parkway in Mississauga. HCM together with RWH Engineering proposed an innovative and economical design and construction process for shoring the manholes and access shafts using caisson compression rings. Challenges that had to be dealt with included designing the compression ring to withstand large uneven surcharges caused by a close embankment in addition to large surface loading by a crane. To ensure the safety of the shoring system RWH Engineering is providing precession monitoring utilizing inclinometers.

Client: McNally Construction

Location: Mississauga, Ontario

Dufferin Mall

Dufferin Mall Pedestrian Tunnel

This renovation project includes the challenge of constructing a 10ft wide by 12ft deep pedestrian tunnel inside an active mall. HCM together with RWH Engineering proposed an innovative design and construction process to accomplish this endeavor with very limited working space and tricky access issues. The construction involves:

• Shotcrete shoring to allow for vertical excavation of the tunnel area

• Bob Cat mounted TEI drill for the installation of tie backs

• Removal of excavated material via narrow stairwells and utility corridors

• Supply of materials and tools via narrow stairwells and utility corridors

In addition, HCM’s scope of work includes increasing the depth of an existing elevator pit, building underpinning, exterior stair concrete footings and retaining walls.

Client: EllisDon Corporation
Location: Toronto, Ontario

Alloa Feedermain

This project involved installation of 3 watertight caisson wall shafts. Two rectangular secant pile wall shaft approx 12m deep and one 6m diameter compression ring shaft approx 7m deep. In order to achieve the tight tolerance needed to ensure the shafts were in fact watertight the use of a guide wall was implemented. The guide wall was installed using Styrofoam form and concrete to allow drill casing to be perfectly centered over the drilled holes.

Client: McNally Construction
Location: Brampton, Ontario

Mount Royal University Conservatory

Design considerations for the foundations were similar to previous projects in the area, with installation of approx. 220 cast-in-place belled piles. The project design team for structural & geotechnical engineering consisted of local firms of Read Jones Christoffersen Ltd. & Thurber Engineering Ltd. The need for the new addition to a campus was a result of fast growing student population at the Mount Royal University and demands for specialty studies.

The soil conditions at mentioned site consisted predominantly of clay till which is ideal for large capacity belled piles. The shafts for the piles were in the range of:

900mm
1000mm
1200mm
1370mm in diameter.

The bells were sized at:

2000mm
2400mm
2800mm
3400mm
3600mm in diameter

The average basing depth on this project was approx. 12.0m – 15.0m with an occasional need to protect the upper portion of the pile shafts by using temporary steel caising in order to prevent ingress of water into the pile shafts. The average concrete volumes for single piles were approx. 20 – 24 cu. metres. Among the challenges for HCM was installation of piles in close proximity to concrete and steel underground utilities which were present on site as a result of previously demolished structure. In many cases this required coring and managing voids in the shafts after removal of these obstructions. Also, numerous piles were belled in soils with occurrence of large boulders which required special considerations for handling of equipment, customized tooling requirements and operating skills.

HCM finished foundation piling scope of work ahead of planned schedule.

Client: Cana Management
Location: Calgary, Alberta

LRT Slope Protection at Retaining Wall

LRT Slope Protection at Retaining Wall

Slope Remediation

Slope Remediation

Eglinton LRT – Cedarvale Station SEM and SOE

Eglinton LRT – Cedarvale Station SEM and SOE

Telus Sky tower

Telus Sky tower

Upper House Condominiums

Upper House Condominiums

Sage Condominiums: Phase II

Sage Condominiums: Phase II

K2 Condominiums

K2 Condominiums

65 Lillian Street Condominium Building

65 Lillian Street Condominium Building

Twinning of the West Trunk Sanitary Sewer

Twinning Of The West Trunk Sanitary Sewer

Dufferin Mall

Dufferin Mall Pedestrian Tunnel

Alloa Feedermain

Alloa Feedermain

Mount Royal University Conservatory

Mount Royal University Conservatory

We are at your service since 2001 with full-service geotechnical excavation, shoring and foundations, specialized in sustainable foundations, including Shotcrete and Structural Shotcrete.

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