Background Information and Challenge
The Burgoyne Bridge, located in the Niagara region, is a critical artery connecting downtown St.Catherines to the city’s west end. The 400m long Bridge spans the 12-mile creek, Highway 412, and sensitive fish habitat and Conservation area. The original structure was built back in 1912. As a result of years of degradation and increased demands, a decision to repair or replace was required. Assessment by an engineer estimated the useful life of approximately seven years in its current state. A decision was made to replace the entire structure with a new and modern bridge system suitable for many years to follow.
A geotechnical survey revealed that the soil condition over bedrock was subject to considerable settlement. As a result, a lightweight fill such as Expanded Polystyrene would be required to minimize this settlement. EPS was chosen as a lightweight fill option however required a geomembrane protection layer to protect from degradation from liquid hydrocarbons such as diesel, gasoline, kerosene, and hydraulic fluid. The geomembrane lining system would need to withstand the long-term design of the structure (excess of 100 years), primary contact with hydrocarbons, and flexible in nature to conform to the 90 degrees corns and angles of the EPS.
Solution
Layfield proposed the Enviro Liner® 6040 Geomembrane liner for the application. Enviro Liner® 6040 is a flexible fortified LLDPE/HDPE geomembrane lining system manufactured and installed by Layfield Geosynthetics. The flexible geomembrane is manufactured with prime-grade resins and antioxidants to deliver a long-term reliable protection system. The lining system has excellent chemical-resistant properties and is suitable for the containment of solvent and water vapors. Independent permeability testing was completed for various popular fuels to satisfy the client. The membrane is durable and able to resist puncture and backfilling in an under-slab application. The flexible properties of this system allowed prefabrication and tailored fit to wrap the EPS blocks.
Installation of the lining system was completed in 2 phases by Layfield installation crews. Phase one included the abutment, and phase 2 was the abutment. Layfield used a combination of prefabricated shop fabricated lining panels and roll stock fusion welded on site. A split wedge welding was used, which allowed the installation to pressure test the seam for any seam leakage. Layfield worked closely with the site contractor to coordinate the installation schedule.
Results
The project was completed on time and on schedule with the contractor. The Bridge was commissioned in 2017. The task was particularly challenging as our crews were required to coordinate closely with the contractor’s construction schedule, which took time to predict. Both the owner and the contractor were happy to work with Layfield and look forward to working together on future projects.
