MDOT Completes State’s First Bridge Slide

Despite taking nearly 23 hours, more than double the anticipated time to complete the slide, the Michigan Department of Transportation successfully completed the state’s first slide-in bridge replacement on Sunday.  MDOT chose a bridge spanning Three Mile Road on US-131 to try out the Accelerated Bridge Construction technology.  In order to complete the project, a new 1.5 million pound bridge was built adjacent to the existing bridge.  The old bridge was then removed and the new bridge was slid into its permanent place using dish soap as the lubricant.  Instead of having to detour northbound traffic on US-131 for up to five months, the slide-in bridge technology means the northbound traffic will only be diverted for one week.  According to MDOT, the bridge slide technolgy’s ability to save drivers time and money is the key reason why it will become the new norm in bridge replacement when space permits.

Slide-in Bridge Technology is one of several Accelerated Bridge Construction technologies currently endorsed by the Federal Highway Administration Everyday Counts program.  According to the FHWA, the main advantages to slide-in bridge technology are improved safety, quality and durability as well as reduced construction and user delay costs.  Since the new bridge is being to built adjacent to the existing span there is a much lower chance of a pedestrian worker being struck by a vehicle. 

MDOT released a video overviewing the slide-in bridge process.  Although each job will vary due to the specific jobsite requirements, the video shows each of the main steps that occur in each bridge-slide.  The video can be found embedded under “Media” below.  MDOT will use the same procedure to slide the southbound US-131 bridge into place in mid-September.  They also plan on using the method to replace the M-50/Alden Nash Bridge over I-96.  Due to the heavier weight of the M-50 bridge, it will need to be pushed into place rather than pulled like the US-131 bridge.  More information about slide-in bridge construction can be found on the FHWA's website.