Union Pacific Railroad Overpass Roadway Design
Trihydro contributed to the Environmental Assessment and led the development of construction documents, including design for a two-span overpass over the Union Pacific Railroad in Laramie, Wyoming.
The Clark Street Viaduct served the City of Laramie for more than 50 years, providing a critical connection over the Union Pacific Railroad (UPRR). Over time, however, the structure began to deteriorate, requiring significant maintenance and creating a bottleneck that reduced service levels. Safety was also a concern. The intersection of Clark Street and Third Street, located on the east approach to the viaduct, lacked turning lanes and carried high traffic volumes, resulting in crash rates up to four times higher than statewide averages.
To address these issues, WYDOT and the City of Laramie determined that a new centralized corridor was necessary. Their goal was to create an efficient east–west connection that could handle future traffic demands while improving safety, roadway operations, and long-term infrastructure performance. Throughout the project, the team engaged WYDOT, adjacent landowners, and the traveling public through stakeholder meetings and public outreach.
The project replaced the aging viaduct with a new two-span overpass across the UPRR, creating a direct connection between Laramie and West Laramie. Trihydro supported the effort by contributing to the Environmental Assessment (EA) and leading the development of construction documents, including bridge and roadway design. Work involved removing the previous structure, widening the bridge over the Laramie River, constructing the 400-foot-long UPRR overpass, and installing retaining walls along the approach fills.
Environmental Assessment
Our team developed roadway alignment alternatives for the overpass and associated connecting roadway, which were used in the EA. During this phase, we also assisted with construction cost estimating and public involvement.
Developing the Roadway Design
Once the EA was completed, Trihydro, as the prime engineering consultant, led the design effort of the preferred alternative. Our team was responsible for project management, which included coordinating between the electrical consultant, landscape architect, WYDOT’s Right-of-Way, Traffic, and Bridge Programs, and the City of Laramie (City). The preferred roadway alignment required relocation of some municipal utilities and a new stormwater drain, which Trihydro designed.
Utility Improvements
The City chose to make utility improvements while the roadway was under construction. Trihydro’s Rocky Mountain Infrastructure and Water/Wastewater Team prepared these designs, which included a new stormwater pipeline, sanitary sewer, and water distribution line improvements. Special provisions were prepared for the water line and sanitary sewer work, meeting City standards. These documents were prepared in a Wyoming Department of Transportation (WYDOT) format.
Public Relations
This project included extensive public involvement from the early EA development through design development. Trihydro prepared exhibits and 3D models, assisting the public in visualizing the proposed overpass structure and its location upon completion. Our staff also attended public meetings to answer questions and receive input.
Project Recognition
In 2019, the Wyoming Engineering Society (WES) selected this project for the 2018 President’s Project of the Year Award. The award was presented to WYDOT, Trihydro, and the City of Laramie at the annual WES Convention in Cheyenne.
