The Challenge of Arch Culvert Rehabilitation
Unlike circular pipes, arch-shaped culverts present a unique challenge when it comes to structural rehabilitation. Their non-round geometry and sometimes integrated parapet walls mean that standard sliplining methods don't always apply. However, just because a culvert isn’t round doesn't mean it can’t be effectively relined.
By using custom-fabricated HEL-COR® half-round corrugated steel pipe, engineers can match the shape of the existing arch and restore its structural performance while minimizing excavation, roadway disruption, and overall project cost.
Why HEL-COR® Half-Round Pipe?
For reline applications, HEL-COR® half-round pipe can be designed to closely match the existing culvert geometry.
Key Benefits, include:
- Structural Performance: Once installed and backfilled or grouted, the steel liner works compositely with the host structure to handle imposed loads.
- Shape Customization: Half-round and horseshoe shapes are available to match existing arch culverts with minimal annular space.
- Efficient Installation: Reduced excavation means faster construction times and lower overall project risk.
- Long-Term Durability: When combined with a protective coating and proper grouting, HEL-COR® provides decades of added service life.
Designing for Strength: The Role of Corrugation
The performance of any steel liner depends on its stiffness—and that comes from both the steel gage and the corrugation profile. The deeper the corrugation, the greater the moment of inertia and structural stiffness of the liner.
HEL-COR® is available in 1/2" and 1" corrugation depths. Additional structural plate and tunnel liner plate options are also available in 1 3/4" - 5 1/2" corrugation depths.
Deeper corrugations allow for greater structural efficiency, meaning wider spans and thinner steel gages can be used, resulting in cost savings and easier handling on site.
Corrugated steel arches have been successfully installed in spans up to 50 feet in reline applications, demonstrating their capacity for even large-scale culvert rehabilitation.
Complementing Existing Structures
In many older arch culverts, vertical walls were constructed using brick, stone, or cast-in-place concrete. In some rehabilitation projects, these walls are still structurally sound or can be stabilized with additional concrete. When this is the case, the walls can serve as both structural reinforcement and as a formwork for placing the new HEL-COR® liner.
By integrating the existing structure into the new design, project teams can reduce material and installation costs while preserving historically significant or hard-to-replace infrastructure.
Photos Above: 42-inch span corrugated steel half round arch was used to reline an existing brick arch culvert. The corrugated arch is bolted together in the field. Grout plugs were welded at the factory in the crown of the arch. Grout plugs help assist in the back grouting process during the reline installation.
Conclusion
When it comes to aging or failing arch culverts, replacement is no longer the only viable path forward. Trenchless relining with HEL-COR® half-round corrugated steel pipe offers a durable, cost-effective, and minimally disruptive solution for extending the life of historic water crossings.
Contech’s HEL-COR® system can be tailored to meet the specific shape and performance needs of your project—helping infrastructure owners protect their assets while minimizing downtime and expense.
Want to learn more about HEL-COR® arch reline solutions? Contact your local Contech representative or explore our technical resources to see how we can support your next rehabilitation project. www.conteches.com/connect