DRAINAGE DESIGN CASE STUDY:

The installation of seven JET Filter JF6PC 6-inch Maintainable Drains at the CDOT I-70 / Colfax Ave project significantly enhanced the bridge abutment drainage system, ensuring long-term structural stability and reducing the risk of erosion.

This Colorado bridge project completed by the Colorado Department of Transportation (CDOT) faced a critical infrastructure challenge with two structurally deficient bridges on I-70 over Smith Road and the Union Pacific Railroad. The existing welded steel girder bridges, featuring a cast-in-place concrete deck, had deteriorated over time, leading to concerns about their long-term viability.

Given the bridges’ horizontal and vertical curvature, along with their 43-foot width accommodating two lanes and 8-foot shoulders, proper drainage solutions were crucial. Without adequate drainage, water buildup behind steel sheet piling used in the abutment structures could lead to increased pressure, structural weakening, and eventual failure. To mitigate these risks, CDOT needed a reliable and maintainable drainage solution to manage hydrostatic pressure reduction.

JET Filter System provided an advanced drainage solution by installing seven JF6PC Maintainable Weep Hole Drains. Each drain featured a 6-inch diameter open-end ASTM Powder Coated Steel Housing and a Mirafi® Filter-Weave FW 300 Geotextile Filter Media to ensure effective water flow while preventing soil migration.

The JET Filter drains were integrated into the bridge abutment’s steel sheet piling, allowing controlled water drainage from behind the structure. This method eliminated the need for extensive excavation or retrofitting, ensuring an efficient and cost-effective installation process. The maintainable design allows for future inspection and cleaning, prolonging the system’s effectiveness and reducing maintenance costs.

The result was a dramatic improvement in drainage efficiency, reducing hydrostatic pressure behind the abutments, enhancing structural integrity, and extending the bridges’ lifespan.