Hamilton Kent Blog

B.C.’s solid investment in precast box culverts

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Maple Ridge, B.C: home to astonishing views of Canada’s Rocky Mountains, clear blue skies as far as the eye can see, and… rusty metal culverts.

At least that was the case before the local government commissioned Langley Concrete to provide their precast concrete box culverts to replace the metal culverts, which had—clearly—reached the end of their service life.

Metal culvert failures

The signs of a failing metal culvert are easy to spot: Rust, perforations through the metal that lead to soil erosion and movement in the culvert, or at its worst—collapse. If a culvert collapses, it blocks water from being directed safely downstream, which can lead to flooding.

Not only that, it can also cause roadway failures and endanger the lives of people around it. An example of this happened at an IHOP in Mississippi last year when a metal culvert failure caused a major sinkhole and car pileup in the restaurant’s parking lot.

Depending on varying environmental factors (such as frost, soil properties, and ground water), metal culverts are estimated to have a lifespan of 50 to 75 years. Currently, most states design their major highway culverts based on that estimate, but a Missouri Department of Transportation study estimated that the lifecycle could even be as low as 20 years, depending on whether culverts are being properly protected from corrosion.

Long lifecycle precast culverts

Joel Shimozawa is a technical marketing engineer with Langley Concrete. He thinks it’s important to educate the industry on newer technologies like precast concrete culverts, which have an estimated lifespan of 100 years.

“Metal culverts are a cheaper product to install upfront, but when you consider the lifecycle analysis, they’re not actually a cheaper product because they don’t last as long,” said Shimozawa. “We hope that the industry will strive to make better decisions.”

Unlike metals, precast box culverts don’t have rusting surfaces and therefore don’t need additional protection in order to keep them in working order.

Maple Ridge and Sunday Summit Projects

Langley Concrete provided gasketed box culverts for both B.C. projects in Maple Ridge, and one in Sunday Summit. The Sunday Summit culvert was part of a highway realignment project tendered by British Columbia’s Ministry of Transportation.

“That was a project to increase safety for road users. There were a series of hairpin turns, so the Ministry of Transportation wanted to straighten out the highway and make it safer,” said Shimozawa.

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“I think they selected precast box culverts because of the ability to build structure into that type of building material and the 22 meters of earth cover on top of the culverts,” said Shimozawa, who noted that it would be difficult to install a flexible type of product for this type of application.

With culverts, soil stability is just as important as stability of the culverts themselves. If the soil is unstable and begins to move, it can take the culverts with them.

Labor savings with gasketed culverts

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Gasketed culverts come ready to install. Usually precast culverts need on-site application of watertight jointing material. For the Maple Ridge and Sunday Summit projects, however, Langley Concrete’s gasketed culverts included pre-installed Tylox SuperSeal™  Box Culvert Gaskets from Hamilton Kent.

“It really simplifies things for the contractor and allows them to install these culverts and carry on,” said Shimozawa. “They would have had to grout these culverts in the past. They no longer have to do that.”

The contractors were then able to save time and labor by laying each box section with their sockets facing upstream using a crawler crane. Langley Concrete supplied a pipe puller with the projects.

“It’s basically a hydraulic unit, it locks itself into a culvert to assist with the installation and pull a joint tight,” said Shimozawa. “If the joint is in tolerance, it’s really a plug and play installation for the contractor.”

If the joint is not in tolerance, then some extra grouting may be required to make sure that the gaskets stay watertight.

“As far as work site safety goes, you no longer have to be inside these culverts that could be a confined space,” explained Shimozawa, explaining that he’s been on sites in the past where workers were on their hands and knees crawling through culverts.

Next up for Langley Concrete and Hamilton Kent is Site C, a hydroelectric dam in northern B.C. that will require 200 meters of gasketed box culverts.  

Keep checking our blog for updates on how gasketed box culverts are helping Site C as the project goes on.