I-90 Mississippi River Bridge Approaches and US 61/14 Interchange

Multi-state Corridor Reconstruction and Bridge Approach Design

As part of a major infrastructure upgrade to the I-90 crossing over the Mississippi River, SRF led the complete reconstruction of the inland approaches, including three miles of retaining walls and seven inland bridges, four of which are complex, curved steel structures. Working under an aggressive schedule, SRF delivered final design plans for more than $100 million in improvements to this key transportation corridor.

Multi-jurisdictional Coordination and Project Management

The project required close collaboration with MnDOT, WisDOT, and several federal agencies, including the U.S. Fish & Wildlife Service. SRF developed detailed construction staging and maintenance of traffic plans while meeting strict drainage criteria given the corridor’s proximity to the Mississippi River. The team also integrated the design of the Wisconsin approach roadways to align with the relocated I-90 river bridge structures.

Visual Quality and Design Oversight

To complement the scenic river crossing, SRF led visual quality efforts that enhanced the aesthetic design of the bridge and interchanges. Our team conducted regular design reviews, facilitated interagency coordination, and developed a comprehensive Design Quality Management Plan and Project Manual to ensure consistency and quality throughout the project lifecycle.

Complex Drainage and Stormwater Design

The steep terrain and narrow corridor required deep excavations and advanced drainage solutions. SRF designed nearly 25,000 linear feet of storm sewer and culverts, incorporating rehabilitated and new pipes. Notable techniques included pipe jacking to cross an active rail line and the installation of 2,000 feet of steel casing to protect infrastructure near retaining walls. Additional work included bridge deck drainage analysis, energy dissipation structures, and culvert lining.

Intelligent Transportation Systems (ITS)

To support safety, incident response, and traffic operations, SRF designed and implemented a robust ITS network featuring:

Four closed-circuit television (CCTV) cameras with full interchange coverage
Two dynamic message signs (DMS) for traveler information
A weigh-in-motion (WIM) system for commercial vehicle enforcement
Anti-icing systems on all bridge spans

Given the remote setting, SRF engineered a wide-area communications solution utilizing existing and planned Wisconsin fiber infrastructure, ensuring reliable, high-capacity data transmission for both Minnesota and Wisconsin agencies.

Resource Links:
I-90 Bridge Reconstruction
WisDOT
U.S. Fish & Wildlife Service