2nd Street Bridge Brings A Community Back Together
The design of a bridge reflects not just a path over an obstacle, but also the joining of two areas of land that are separated. For Otak’s designers, the 2nd Street Avenue bridge in Lyons, Colorado, had a third purpose, which was to put a community back together after it had been devastated by the 2013 floods.
When the floods hit, water beat on the bridge for several days and a fallen log hit one of the key structural supports. Flood debris covered the bridge’s piers causing water to infiltrate the town’s wastewater treatment plant, destroy a storage building and equipment used by the town’s Public Work Department, and damage a downstream bridge. Eventually, the damaged and unsafe bridge took away the connection between the town, two housing subdivisions, a church, a school, a park, and a recycling center.
Otak was hired by the town to do emergency repairs to the bridge and to design the new structure. Zak Dirt was brought in as the contractor. Various engineers worked on the project throughout its lengthy design process, with Otak’s Structures Group Manager Dan Beltzer finishing out the job. “We had a great team to guide this work. The design really shows how simply rebuilding isn’t always enough. This bridge was built back better as a sustainable structure that will last well into the future,” Dan says.
The new single-span bridge is 139 feet, crossing the St. Vrain Creek. The design was approved in the fall of 2019 and construction started in 2020 with a cost of about $4 million funded in part by FEMA with assistance from the Colorado Community Development Block Grant-Disaster Relief program. The new bridge was built six feet higher than the original structure, to convey the 100-year storm event to allow for future floodwaters and debris to safely pass under it. It was also built to withstand a 500-year scour event. Dan says scour is the number one reason bridges collapse.
The project was unique in that it was the first bridge in the state to use the Colorado Department of Transportation’s new Bulb-Tee concrete girder shape. “Colorado’s new standard provides more girth, which allowed us to further minimize the required bridge depth as compared to the previous standard – which helps the hydraulic conveyance while minimizing the required raise in roadway grade. The new standard became available very late in the design process and none had yet been built. In fact, only one fabricator had the ability at that time to construct the girders. Still, pricing and learning-curve concerns gave way to the design benefits.” Dan comments.
A ribbon-cutting was held on July 8 to celebrate not just the completion of the bridge and one of the last FEMA flood recovery projects in the community, but the resiliency of Lyons. Dan says the ceremony also stood as a memorial to Jim Blankenship who served as the town’s engineer for over a decade, and worked with Otak on several projects, including the Main Street Reconstruction project, which won the APWA Colorado’s overall Project of the Year award. The event drew dignitaries, such as Colorado Senator John Hickenlooper, Congressman Joe Neguse, and Lt. Governor Primavera. The officials touted the ability of not just Lyons, but of any community, to build back better and ensure a safer future.