Any engineer can tell you that large projects often demand special consideration in design. This was certainly true of the nine massive box culverts County Materials built last year for Walter Energy, Inc.
The culverts are part of an emergency spillway to allow water from a pond to flow underneath railroad tracks near Chetwynd, British Columbia. The project is designed to protect the railway in the event of a “200-year flood” type of rainfall.
It is also designed for heavy use – the culverts are built to Cooper E-90 specifications. This means they can handle train loads of up to 90,000 pounds per axle.
To accommodate the wide span and heavy loading requirements, the culverts feature dual cell construction – a first for County Materials in a culvert of this size. Each cell measures 4 x 1.25 meters. Two of the boxes weigh in at 40 tons each; the other seven are even heftier at 53 tons apiece. Each dual cell section was poured as one monolithic unit.
The culvert sections were shipped to the site by rail and installed in September of 2012. “We hope it doesn’t end up getting used for what it was designed for,” comments Jeff Cruce, Project Development Director at Walter Energy, “because a 200-year rain would destroy a lot of stuff. It would basically wash away everything else – except the culvert!”