When construction of the US-31 freeway began in southwest Michigan in 1981, its purpose was to connect I-94 and I-96 with I-90/I-80 near South Bend, Indiana. Due to environmental and budgetary constraints, a portion of the US-31 Connector to I-94 in Berrien County, Michigan was never completed.

For nearly 40 years, drivers have exited either I-94 or US-31 onto Napier Avenue to continue their journey into southwest Michigan or northern Indiana. After many years of planning, construction of the US-31 Connector final segment began in 2020.

SME worked with the design-build team to evaluate the risks associated with design and construction of the proposed bridges, large culverts, and earthwork associated with the project. Bridges utilized mechanically stabilized earth (MSE) abutments and either shallow or deep foundation systems at the interior piers.

SME worked with the design team to provide recommendations for shallow (spread) foundations and deep foundation recommendations including pile types and estimated lengths. External stability analyses were performed for the MSE walls to provide minimum soil reinforcement lengths. SME also assisted during the pre-bid phase to evaluate the conceptual 30% plans and assist the team in developing quantities related to the foundations for the new structures.

Throughout construction, SME assisted with foundation subgrade observations and recommendations for improvement. Some challenges at the bridge and roadway subgrades included improvement of moisture-sensitive silty soils and perched groundwater and isolated undercutting below new foundation elements.