There are two Union Pacific freight rail tracks carrying nearly 70 trains per day traveling through Jefferson, Iowa at speeds up to 70-miles per hour. Snyder & Associates performed a feasibility study to assess the practicality of constructing a grade separation of Iowa Highway 4 and the Union Pacific Railroad to alleviate traffic delays and safety concerns for pedestrians and vehicles.
Feasibility studies evaluate the viability of a project to ensure it’s technically, legally, and economically justifiable. There are many project benefits to conducting a feasibility study, including the opportunity to provide stakeholders a clear picture of the purposed project. A steering committee was formed with representatives from local businesses in the city of Jefferson, Greene County, Iowa Department of Transportation District 1 staff, Union Pacific Railroad, and Snyder & Associates to engage stakeholders and develop project alternatives. Once the study was determined feasible, it was finalized and adopted by the Jefferson City Council with questions arising around the preferred alternative.
Several alternatives were evaluated to address stakeholder concerns. A final recommendation on the preferred alternative was concluded after subsequent meetings with the steering committee and Iowa Department of Transportation staff members. The preferred alternative included constructing a four-lane, eight-span, 1,100-foot long bridge structure at the intersection of State Highway 4 and the Union Pacific Railroad tracks. To minimize access impacts to local businesses, the bridge spans McKinley Street, which is located just south of the railroad.
Recognizing the need to accommodate for the future growth, the bridge was designed for a third railroad track and was constructed adjacent to a property on the National Register of Historic Places. The bridge foundations were designed to minimize damaging vibrations during construction.
The project also involved the construction of a new access road system to serve businesses without direct access to the highway. Staged into two construction contracts, the access road and detour route improvements were constructed in 2011, while Iowa 4 and the bridge were constructed in 2012.
Snyder & Associates was the primary design consultant on the project and subsidiary Shuck-Britson provided structural bridge design. Services provided included preliminary roadway design, storm sewer, sanitary sewer, and water main design, right-of-way acquisition, bridge design, mechanically stabilized earth wall layout, preparation of categorical exclusion, staging plan, management of public participation, coordination with franchise utilities, railroad coordination, and a corridor improvement plan. Snyder & Associates managed sub-consultants on the project to perform survey, cultural resource investigations, and geotechnical design. The total project cost was $13 million.