![Curved tunnel extends the limits of microtunneling on a project.](https://www.michels.us/wp-content/uploads/2022/10/Curved-tunnel-extends-limits-of-microtunneling-1080x1350-7.webp)
Congratulations to our crew and project partners for extending the limits of microtunneling technology. Michels completed an exceptional 470-foot drive under the Tualatin River in Tualatin, OR in less than a month. The 84-inch diameter tunnel features a vertical U-curve with a 650-foot radius—a North American record for the tightest curve radius at this diameter.
Michels used a new Herrenknecht AVN 1800 machine with double-steering articulation to navigate the radius of the curve and a jacking system to install a specialized reinforced concrete pipe.
The microtunneling drive is part of a design-build project being executed with Mortenson for Clean Water Services.