U.S. 20 Bridge

Details
Location: Dubuque, Iowa
Services: Planning study, bridge study and capacity improvement project
Project Cost: $131 million
Client/Owner: Iowa Department of Transportation
Completed: 2003

Description
The Iowa Department of Transportation selected Hanson as the lead consultant for improvements to U.S. Route 20 that included a new major river crossing and approximately 3.5 miles of new roadway alignment. The purpose of the capacity improvement was to reduce congestion at the historic Julien Dubuque Bridge river crossing, accommodate anticipated increases in traffic volume and provide the most direct route for traffic crossing the river.

Hanson completed a:

• planning study,
• bridge type, size and location study, and
• environmental assessment.

Services
The planning study included an origin and destination study, traffic projections, and interchange and intersection design studies for the new Mississippi River crossing between Iowa and Illinois.

Hanson assisted with an extensive public involvement program which included coordinating with state and federal agencies, hosting informational meetings and a public hearing, coordinating meetings with affected and interested groups, producing project newsletters and preparing the public involvement record.

The study report recommended construction of a new river crossing bridge, with two lanes and a bicycle/pedestrian path, adjacent to the existing bridge to form a one-way couple. The project also included two miles of new U.S. 20 alignment, a grade-separated interchange in Dubuque, two grade separation structures, retained earth embankments, and reconstruction of Business Route 20 in East Dubuque.

Services completed also included a summary of the available geologic, pedologic, and engineering information for the roadway corridor, as well as consideration of potential problems related to subgrade soils, ground water, cut (including excavations into existing rock bluffs) and fill sections, and structure foundations for the location study report.

The environmental studies included noise analysis, 4(f) analysis, agricultural impact assessment, air quality analysis, wetlands delineation, ecological resources evaluation, cultural and architectural resources evaluation and technical report, water quality assessment, socio-economic analysis and an environmental impact statement preparation. The environmental assessment addressed the critical environmental issues of the project.

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