When an aging steel culvert needed to be replaced on the 70-year-old Alaska Highway in BC, an innovative Dur-A-Span reline solution was chosen to avoid a costly detour and prolonged traffic interruptions.
Aggressive conditions called for aluminum
It was determined that the site’s aggressive environmental parameters had caused the corrosion of the existing steel structure, so corrosion/abrasion-resistant Dur-A-Span was recommended.
Lightweight Dur-A-Span was a natural choice
The Dur-A-Span round pipe was mostly built outside the existing structure and slid into place using a slipline method. Structural aluminum plate is one-third the weight of steel, making it easier to handle with less torqueing. Grouting filled the space between the two structures, which was larger than usual due to sagging in the middle of the old culvert.
Excessive settlement required a smaller reline
We did the initial work-up and conceptual for Public Works Canada in 2004, when the existing structure’s invert was first showing corrosive perforation. Then the project was shelved for a few years. When it was resurveyed in 2010, it had sagged further and our reline structure now had to be re-engineered to be smaller but still able to satisfy the hydraulics and fish passage requirements.