Briarwood Bridge No. 10427

Scope of Work

The bridge replacement consisted of three main components:

Instream Works:

• Modifying the streambed to align with DFO requirements, ensuring improved flow and habitat conditions.
• Site isolation while constructing instream works.
• Installation of Class 100kg Rip Rap below the High-Water Level.

Design and Construction of Temporary Detour:

• Relocation of an existing temporary bridge onto newly constructed abutments and approaches to maintain traffic flow during construction.

Main Bridge Construction:

• Removal of the existing approaches.
• Excavation for foundations to prepare the site for new construction.
• Construction of a geosynthetic reinforced soil-integrated bridge system(GRS-IBS) abutments, ensuring long-term structural stability.
• Installation of 980m³ of Class 100kg riprap for scour protection, safeguarding the bridge against erosion.
• Placement of concrete girders and a cast-in-place concrete deck to complete the main structural elements.
• Paving of the bridge deck and approaches to provide a smooth and durable driving surface.

Challenges & Solutions

The Ministry of Transportation & Infrastructure awarded Copcan the contract on August 23rd, 2023, with a fish window from August 15th to September 15th, leaving limited time to complete the instream works. The project was considered urgent, as another flood event could erode the temporary bridge and again cut off access to the small community. To advance the project, Copcan collaborated with our Registered Professional Biologist and DFO to secure an extension of the fish window to October 1st. Upon award, Copcan immediately began preparing submittals, including the Traffic Management Plan, Environmental Management Plan (with a site isolation plan), and Rip Rap testing for Acid Rock Drainage (ARD). Despite the tight timeline, Copcan successfully completed all in-stream works within the fish window, demonstrating a commitment to environmental stewardship, efficient project management, and the community’s safety and accessibility.

During the foundation excavation, it was determined that the bearing material for the Reinforced Soil Foundations (RSF) was unsuitable. The original design restricted over-excavation, as the RSF needed to rest on native soil to achieve the required bearing capacity. Copcan collaborated with the owner and the geotechnical engineer to conduct additional testing, enabling the design engineer to make necessary modifications. The revised design involved lowering the wall elevation, increasing the size of the tiebacks, and enlarging the RSF’s width and depth. This adjustment created a conflict with the detour abutments, which were designed based on the initial wall configuration. The proximity and increased depth of the revised foundations risked undermining the detour abutments that were already supporting live traffic. To address this issue, Copcan enlisted our structural engineer to design a sheet pile wall to stabilize the detour. Working closely with our sister company, CDI, we developed a cost-effective, schedule-friendly solution that ensured the project could proceed successfully.

Overall Impact

Construction began on September 26th, 2023, starting with clearing and grubbing activities, followed by in-stream works. Copcan successfully completed all in-stream works before the extended fish window deadline, demonstrating efficiency and adherence to environmental timelines.

Throughout the project, Copcan worked closely with the owner to address design conflicts related to the detour and the geosynthetic reinforced soil-integrated bridge system (GRS-IBS) abutments. Resolving these design issues caused a significant 4-month delay. To mitigate the impact on the project timeline, Copcan implemented an intensive work schedule, operating 12-hour days, 6 days a week, to accelerate progress and limit delays.

This project was a high-priority initiative for the Ministry, serving as a pilot project for the GRS-IBS abutment system, which is envisioned for future applications where a portable concrete plant may not be feasible. The successful implementation of this system resulted in a durable and reliable structure, ensuring uninterrupted access for the local community. This achievement highlights Copcan’s ability to navigate complex challenges while delivering quality results under tight constraints.