LOWELL TOWNSHIP, Mich. (WOOD) — The Alden Nash Avenue/M-50 bridge over I-96 has been opened to traffic in its permanent spot.
The overpass south of Lowell was replaced using slide-in bridge construction, when a new bridge is built next to the old, then the old bridge is demolished and the new is slid into place. Traffic had been driving on the new overpass for weeks, though it was not yet in its permanent spot. The Michigan Department of Transportation closed the bridge this weekend to push it into place.
The slide started Friday night. MDOT said it took crews five and a half hours to move the 4.5 million-pound bridge 75 feet to the east.
MDOT said the bridge was moved with two 70-ton push cylinders at each end of the west side of the bridge and a 95-ton push cylinder in the center, as well as a 35-ton pull cylinder on the center of the east side of the bridge.
That means it took 270 tons of initial force to get the bridge in motion, after which the pull cylinder was turned off. 235 tons of force kept the bridge moving three feet with every push.
MDOT started the slide using what it called a “high-tech” lubricant, but that lubricant started to congeal when the bridge was only halfway home. Crews instead went to a local store and picked up Dawn dish soap to use instead, which MDOT says worked better than the lubricant.
After the bridge was in its final spot, crews worked on the roadway leading up to it.
I-96 under the overpass was completely reopened by 7:15 a.m. Saturday, and Alden Nash opened to traffic at 6:30 a.m. Monday — only about an hour and a half later than MDOT had originally planned.
Below, watch an MDOT timelapse video that includes narrated information about the push. Longer timelapse video of the push courtesy MDOT, which does not have narration, can be watched above.
MDOT says slide-in bridge construction saves drivers time and money by decreasing how long detours have to be in effect. In the Alden Nash case, there were only two weekend closures: One for the demolition of the old bridge and one for the slide. Other than that, the highway and bridge were open to traffic.
The slide was only the third in Michigan history, MDOT said, and it was the first at an interchange.
MDOT will still be working in the area of the new bridge until November.