Northwest Pipe Company Introduces the Radial Bending Joint for Steel Pipe Microtunneling

17 November 2022

Northwest Pipe Company a leading manufacturer of water-related infrastructure including engineered pipeline systems and precast products, has developed the Permalok Radial Bending Joint (RBJ) that enables steel pipe to be installed in a curved radius in  microtunneling applications

This patent-pending technology is a ground-breaking advancement in trenchless microtunneling construction. The Northwest Pipe Company team developed the proprietary joint design to meet a target radius curve of 800 feet during trenchless installation.

Permalok steel pipe is most often used as a casing pipe for utilities and excels in trenchless jacking applications including microtunneling, pipe jacking, auger boring, and pipe ramming. The press-fit machined joints reduce field time by eliminating butt-weld joints and result in a shortened install duration and reduced field costs. To solidify the joint's validity, the Permalok® RBJ has undergone Finite Element Analysis at the University of Thessaly Department of Mechanical Engineering.

"This joint changes the way we have all thought of microtunneling construction," states Scott Montross, President and Chief Executive Officer of Northwest Pipe Company. "We have developed a solution that enables steel pipe to curve during trenchless construction, which makes microtunneling even more feasible in constrictive or challenging environments. For years, trenchless applications have been limited by a straight installation path—but not anymore."

The Company manufactures Permalok® RBJ in pipe diameters varying from 30 to 156 inches. The actual curve radius is dependent on site conditions as well as the pipe diameter and length.

About Northwest Pipe Company – Founded in 1966, Northwest Pipe Company is a leading manufacturer for water-related infrastructure products. In addition to being the largest manufacturer of engineered steel water pipeline systems in North America, the Company manufactures high-quality precast and reinforced concrete products; water, wastewater, and stormwater equipment; steel casing pipe; bar-wrapped concrete cylinder pipe; and one of the largest offerings of pipeline system joints, fittings, and specialized components. Strategically positioned to meet growing water and wastewater infrastructure needs, Northwest Pipe Company provides solution-based products for a wide range of markets under the ParkUSA, Geneva Pipe and Precast, and Permalok® lines. The Company's diverse team is committed to quality and innovation while demonstrating the Company's core values of accountability, commitment, and teamwork. The Company is headquartered in Vancouver, Washington, and has 13 manufacturing facilities across North America. Please visit for more information.

Aaron Wilkins  
Chief Financial Officer  
Northwest Pipe Company
360-397-6294 •

SOURCE Northwest Pipe Company