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

Odeon Ronmore Development

HCM was contracted to provide the design and installation of shoring system for a mixed use commercial development in the main corridor of the Garrison Woods area SW Calgary. RWH designed a tied-back pile and timber lagging shoring system to support the vertical excavation for the foundation wall along the majority of the building perimeter. Due to overhead power restrictions and minimal clearances to the property line, the laneway side of the project was supported by a soil nailed shotcrete system. The laneway shoring presented various challenges including anchor encroachment limitations that could not exceed 6.0m to the adjacent property. Anchors were tightly spaced and injection grouted bars installed to gain increased soil adhesion. Regular site inspections and monitoring was performed by RWH to review the performance of the shoring and confirm the design during all stages of the excavation. The shoring was designed for a maximum excavation depth of 10m below grade for a total of 13,200 SF of shoring area.

HCM finished this project on schedule working with the General Contractor to escalate excavation activities and meet the occupancy milestone outlined by the owner.

Location: Calgary, Alberta

Customer: Chandos Construction Ltd.

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.

Oshawa Mall

The Oshawa Mall expansion was a large project that required several foundation and shoring services. HCM met the needs of the contractor by providing both tied back and cantilevered lagging shoring systems, shotcrete underpinning, and installation of caissons.

Client: Ledcor Construction Ltd.

Location: Oshawa, Ontario

RWH Engineering Inc. (RWH) completed the shoring designs and provided layout, as well as precision and vibration monitoring services. Taking on this additional scope, HCM/RWH were able to provide significant project cost-savings and minimize communication issues. On this project, the shotcrete underpinning design was superior to the conventional underpinning method and resulted in both schedule and cost savings due to the efficient construction process.

The HCM/RWH team provided services across multiple scopes of work, helping the contractor complete the project on time and within budget.

Weston Road

The Metrolinx Weston Tunnel project will serve as a below grade rail corridor for the GO Georgetown line linking the airport to downtown Toronto. HCM was subcontracted by KO Constructors to design, supply, and install several shoring systems as well as deep foundations.

The project scope consisted of two shoring walls spanning a total distance of 2.6 km, ranging from 4.5 to 14 meters in depth. The shoring walls consisted of both bypass shotcrete and caisson wall to provide railway protection and allow for continuous GO train service. Precise coordination between all parties was required when drilling as close as 100 mm to the operational tracks.

HCM worked closely with the general contractor and owner to meet strict scheduling goals. HCM employed up to 5 large diameter drill rigs at one time, performed night work, and readily adapted to changes in the shoring scope to allow for early excavation and structure installation. RWH Engineering Inc. (RWH), an HC Group company, performed the precision monitoring on the project and was also involved in the design process, enabling accelerated design changes.

The Weston Tunnel project is an example of the service HCM and RWH can provide to a large scale project where schedule goals are important. The HC Group is able to develop solutions and adapt to any changes in conditions allowing the project to progress without delays.

Client: KO Constructors

Location: Toronto, Ontario

Herald Block

HCM was chosen to provide a comprehensive design-build shoring solution for Phase 1 of Brookfield Place development, which will become the tallest building in Western Canada. The excavation spanned a city block and extended 22 meters deep. The shoring system, designed by RWH Engineering Inc. (RWH), was comprised of an 11 meter deep perched caisson wall above shotcrete, which continued into the rock for the remaining depth of the excavation.

The challenges faced on this project included old foundations encountered during drilling, surrounding tightly clustered utilities, vulnerable neighbouring structures, and the adjacent light rail transit (LRT) system. HCM met these challenges with close attention to detail and meticulous planning to prevent any utility conflicts and structural damage. RWH completed the precision monitoring of the shoring and adjacent structures providing weekly reports to all stakeholders for the duration of the project.

Client: EllisDon Corporation

Location: Calgary, Alberta

HCM was able to use their experience on past projects to design and construct a shoring solution that worked with the varying soil conditions at depth. This solution resulted in a more sustainable project as the perched wall required less material than a traditional full depth caisson wall, and provided project cost and schedule savings. Brookfield Place is an example of the ability of the HC Group to work together and overcome challenges in complex projects.

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

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

Great Lakes Copper Plant

The Great Lakes Copper Plant in London, Ontario, posed a technical challenge in shotcrete shoring. HC Matcon helped to facilitate the installation of a new copper roll press. The shoring was completed inside a fully operational copper plant at night and on weekends. Special care was taken to ensure dust and overspray was contained within the work area causing minimal clean up and ensuring the plant was fully functional throughout the process.

HC Matcon, along with Blue-Con Excavating and McKay Cocker (GC), completed the 2,200ft2 shoring in less than three weeks.

Client: MacKay Cocker
Location: London, Ontario

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

Odeon Ronmore Development

Odeon Ronmore Development

Sage Condominiums: Phase II

Sage Condominiums: Phase II

Oshawa Mall

Oshawa Mall

Weston Road

Weston Road

Herald Block

Herald Block

65 Lillian Street Condominium Building

65 Lillian Street Condominium Building

Dufferin Mall

Dufferin Mall Pedestrian Tunnel

Great Lakes Copper Plant

Great Lakes Copper Plant

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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