Twin Ports Interchange Project Named Winner of ACEC/MN Grand Award
DULUTH, Minn. – The "Can of Worms" is gone. ITASCA Minneapolis has completed its role as a key geotechnical consultant for the newly opened Twin Ports Interchange, a project that untangles one of Minnesota’s most complex and economically vital freight corridors connecting I-35, I-535, and TH 53 in Duluth. The technical complexity and local impact of this project resonated with the engineering community, who voted it the winner of a 2026 Grand Award from the American Council of Engineering Companies of Minnesota (ACEC/ MN) at its annual Engineering Excellence Awards.
The original site involved significant challenges with several aging bridges, unsafe geometric design conditions, contamination, and soft, variable soils. But shutting down one of Minnesota's busiest tourist and freight routes wasn't an option. To solve this, the Minnesota Department of Transportation (MnDOT) used the Construction Manager/General Contractor (CMGC) delivery method, bringing the builder (Ames-Kramer Joint Venture) and the design consortium (SEH, Parsons, Barr Engineering Co., and 13 subconsultants, including ITASCA) together early.
ITASCA Minneapolis worked with the team at Barr to develop a detailed 3D numerical model in FLAC3D used to analyze soil-structure interactions and settlement in the subsurface. That analysis was essential to complete the final design of the complex geotechnical ground improvements required to support the new roadway and structures, which included:
- Installation of 6,375 rigid inclusions using two high-capacity rigs and 1,756 driven piles.
- Placement of 13.8 acres of load transfer platforms (LTP) reinforced with geogrids.
- Embankment fill internally reinforced with steel rebars.
The design supported the construction of eight bridge structures and a new culvert, all adjacent to active BNSF rail lines, without stopping rail traffic.
“Design of the ground improvement required close collaboration between Barr and ITASCA to address a challenging site, meet our client's needs and optimize the system within the overall interchange project,” said Barr Senior Geotechnical Engineer Brent Theroux. “This could not have been accomplished without our strong partnership and shared vision to produce high-quality work worthy of a Grand Award.”
The redesigned interchange reduces the number of bridges, upgrades the roadway geometry, and significantly improves safety and efficiency for the high-traffic port of Duluth-Superior, keeping the port’s economy moving for years.
“This project demonstrated the effectiveness of combining ITASCA’s advanced geotechnical modeling with Barr’s engineering expertise,” remarked ITASCA Minneapolis General Manager Tryana Garza-Cruz. “Our collaboration helped deliver a robust foundation for the new interchange, supporting both public safety and long-term reliability. It’s exactly the kind of complex, high-stakes problem we exist to solve.”
About Barr: Barr Engineering Co. provides clients with comprehensive engineering and environmental solutions in the fuels, power, manufacturing, mining, and public sectors. Our nearly 1,200 team members take on high-stakes challenges and deliver lasting outcomes that benefit clients, communities, and the environment. More than a consulting group, Barr is a committed partner and advisor—investing deeply in our work and our clients’ success, across North America and worldwide. To learn more, visit barr.com.
About ITASCA: ITASCA is a global, employee-owned engineering and software firm. We drive the evolution of geological engineering and geosciences to improve the world, collaboratively developing innovative solutions to challenging problems.