North Dakota DOT Tie Back Anchors

Project Overview

Near Theodore Roosevelt National Park on Interstate 94, an active landslide was causing costly annual paving repairs and ongoing safety concerns for the North Dakota Department of Transportation. JDC was engaged to design and install a permanent solution.

JDC installed 81 multi-strand tie back tendons averaging 140 feet in length as part of a grade beam retention wall system. The project was a pilot design for the DOT to demonstrate the effectiveness of post tensioning as a long-term alternative to repeated surface repairs.

One of the defining challenges was the low-strength formation encountered at the site — standard anchor grouting alone could not develop adequate bond strength. JDC employed extensive post grouting techniques to build the necessary resistance, successfully achieving design loads in difficult ground conditions.

Comprehensive instrumentation — including dyna force sensors and load cells — was installed to monitor anchor performance and validate the design over time. As JDC estimator Casey Cooper noted: “Post grouting was the link to success.”