Vermont: Burlington-Winooski Bridge Replacement

How Do You Replace a Broken Bridge? Do the “Lateral Slide!”   

Challenge: Built 95 years ago to accommodate trolleys, the Winooski River Bridge connects the cities of Burlington and Winooski. It’s too narrow for the 25,000 vehicles that cross it daily. Crumbling sidewalks and lack of medians make it dangerous for the 500 pedestrians and cyclists that use it each day.  Replacing the span is a priority for the Vermont Transportation Agency (VTrans), as well as the cities of cities of Burlington and Winooski as well as including features in a new bridge that will improve the connection between Burlington and Winooski and increase bridge crossing safety.    

Solution: Just how do you replace an aging bridge that is the primary conduit between two thriving cities? Conventional construction approaches would close the bridge for several years, creating a traffic nightmare that would force drivers to find detours and damage the area’s economy. Replacement of the existing structure is still in the preliminary engineering phase, but one idea under consideration is called the “lateral slide:” build the new bridge on one side of the current span and slide it into place after the old bridge is torn down. This method closes the bridge for about six weeks, minimizing the project’s impacts on the two communities. Another idea is the use of precast elements. Vermont transportation officials and designer HNTB Corp. are using a $25 million “Rebuilding American Infrastructure with Sustainability and Equity” (RAISE) grant under 2021’s Infrastructure Investment and Jobs Act (IIJA), to figure it all out.                  

What they’re saying:  “Let’s be honest: Every day that we disrupt traffic on that bridge is critical when you have 25,000 cars a day going across it,” Robert White, project delivery bureau director at VTrans, told the Vermont publication Seven Days. “We will have to deliver this project quickly.”