Twin Ports Interchange Project Formerly Known as the "Can of Worms"

When the project is known in design stages as the “Can of Worms,” what could possibly happen when you begin to open the can during construction? Pete Marthaler, MnDOT Construction Manager, and Keri Aufdencamp, Project Environmental Compliance Manager, will walk you through the highlights of the first 1.5 years of construction on the 5-year Twin Ports Interchange Project located in Duluth, Minnesota. Challenges encountered on the project range from a 3+ acre asbestos abatement, contaminated groundwater, contaminated and hazardous levels of soil, trout streams, wetlands, 20 bridge demolitions, encountering an old trestle bridge, bones, a headstone, and the potential to find body bags. What more could you ask of a can of worms?

We’ll start with a narrative of the construction project in general, describing some of the details and highlights such as removing bridges and replacing them with roadway sections on poor geotechnical soils through construction of a load transfer platform. In discussing the overall project, we’ll dive into the complex challenges encountered during construction such as managing contaminated and hazardous levels of soil with a shallow, contaminated water table. These challenges and the solutions that were developed in real time will serve to illustrate environmental risk management and mitigation strategies on a large construction project. Furthermore, we will discuss several Best Management Practices implemented on this project, including construction of off-site engineered lined systems to temporarily stockpile contaminated soil. By examining this and other erosion and sediment control practices, participants can expect to gain perspective of what worked, what didn’t and why, and be able to apply these lessons to future real-world scenarios. Finally, we will highlight what remains to be constructed on the project and what we see as potential challenges to complete the project.