Although used primarily for stream crossing, box culverts are used for any number of buried infrastructure projects. When properly installed, box culverts are designed to last up to one hundred years. Engineered to handle the varying seasonal flows of water, they are also built to handle load pressures from the traffic above as well as compacted dirt on the sides.
Columbia Precast Products standard box culverts meet all Oregon State and Washington State Department of Transportation codes. Mixed, poured, and strength-tested in our controlled facility, we are able to provide fast-turnaround times on these culverts. Even custom-sized culverts can be expedited after engineering has been complete.
Using Multiple Box Culverts
While split box culverts can be made up to 32 feet wide, there are times when several culverts are needed to safely create a stream crossing. Both for the habitat around the stream and any traffic from above. Our culverts are produced with the ability to link multiple culverts together for expanded crossings or longer tunnels.
In order to stay watertight, box culverts are created with specific designs at the opening to create snug joints. Instead of placing culverts side by side hoping for a tight fit, either opening is outfitted with a “bell” or a “spigot” (see pdf) and is “tugged” home during installation with a pipe tugger. In addition, our joint mirrors the FHWA standard design and is widely accepted as an industry standard.
The bell end angles down while the spigot end angles up. When placed together, the bell overlaps the spigot for a more exact fit. However, no matter how perfect a fit (and Columbia Precast box culverts are consistently perfect), a joint compound of some sort still needs to be applied between the bell and spigot to remain watertight.
Smaller applications may use a rubber gasket of sorts to seal the joint between pipes. Think of the little rubber washers used between the garden hose and the outdoor water spigot. On large scale projects, a joint mastic sealant is used.
Mastic sealant is applied to both the bell and the spigot to create a tight bond. Both ends need to be cleaned before application to ensure better adhesion. The mastic seal is pliable at first to allow for movement between the culverts but eventually creates a solid quarter-inch bond.
Advantages of Precast Concrete Box Culverts
In the Pacific Northwest, we value our environment as much as anything else. Considering where box culverts are used, the environmental benefits of precast concrete make it the perfect solution for stream and other crossings. Built to last close to a century, precast concrete won’t bend or rust like steel and is much stronger than plastic.
This means once the culvert is in place, little to no maintenance is required. It won’t need to be rebuilt, replaced, or removed for decades, which means less disruption to the habitat. Concrete itself is an environmentally sound product and Columbia Precast Products was the first buried infrastructure facility to earn SMaRT Certification in the nation.
For many construction projects in Washington or Oregon, requests for proposals include language requiring eco-friendly designs and materials. Precast concrete fits that bill, made with natural and raw materials that won’t seep into the ground. We even choose our partners based on these values.
Unlike corrugated steel culverts that need to be specifically spaced to ensure stability or plastic conduit that needs to be assembled on-site, precast concrete culverts can be placed immediately. When you’re ready for it, we’ll deliver it. It’s truly a set it and forget it product.
As soon as it’s in place, backfilling can begin. Wing walls can also be used to provide more versatility in managing water flow as well. The process is the least disruptive, most efficient way to provide a crossing and protect the environment. Contact Columbia Precast Products to discuss how precast box culverts can help your upcoming project.