Ontario, Canada ā€” Canadian MTO taps Snap-Tite for oval culvert rehab

Oval Culverts Rehabilitated with Culvert Lining Solution

The Problem
Under roads and highways, many corrugated steel pipe (CSP) and concrete culverts are reaching the end of their useful design service life. Installed more than 25 years ago, these CSPā€™s are so significantly rusted that a danger of sink holes, road collapse or flooding exists.
A culvert is a conduit designed to collect water from one area, the inlet, and discharge it out the other end, the outlet. A culvert is in failure mode when water escapes the culvert pipe before exiting the outlet end. As a metal culvert ages, it weakens, separates at the joints and develops rust and holes. As a result, water travels outside the culvert and washes away the roadbed, weakening the entire area and compromising the pavement surface. Left unrepaired, it will only get worse with time. Separated joints and the fatiguing metal will eventually give way and ultimately road failure will occur. Similar conditions happen with concrete culverts when the joints separate, the concrete spalls, cracks and fails to perform as it did when it was originally installed.
Culvert relining is popular with many owners of this infrastructure. Since as many as 40 percent of the culverts under roads in Ontario are oval, there was a struggle to find the most appropriate type of pipe for relining them. Until recently, high density polyethylene (HDPE) pipe, designed to reline culverts, was only available as a round product. The options for repairing failing oval or elliptical steel culverts was to reline them with two round pipes or to simply remove and replace them. While relining is typically the best option for repairing ailing steel and concrete culverts, maintaining flow capacity is a significant concern. Relining an oval-shaped pipe with two round pipes often causes a loss of flow capacity. In many cases, a loss of flow is unacceptable. Further, two smaller pipes inside a larger pipe increases the risk of debris build up and flow restriction.

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