Innovative 'bridge slide' planned for M-100 project

POTTERVILLE – A six-month project to replace a 75-year-old bridge on M-100 this year will involve an innovative construction method used only twice state-wide.

A new bridge will be built next to the existing bridge, used temporarily for traffic while the old bridge is torn down, and then be moved sideways and secured in place.

M-100, which sees some 5,400 vehicles each day, will be closed for just one weekend this fall.

The project, just north of Main Street in Potterville, is only the third time what the Michigan Department of Transportation terms a "bridge slide" has been used by the state's Department of Transportation. The technique has been used on the M-50 bridge over Interstate-96 in Ionia County and on a bridge near Grand Rapids.

The bridge replacement is one of three projects planned for M-100 between Potterville and Grand Ledge in the next two years. The work, estimated at cost of $8.6 million, will begin by early April.

MDOT will also replace two large culverts this summer at the Thornapple and Sharp drains, located just three houses away from one another.

Prepping for the 'bridge slide'

The current bridge runs over a Canadian National railroad track. The new bridge, expected to be in place by October, will be slightly wider with a 10-foot pedestrian path.

The "slide" involves the initial construction of a temporary road and of the permanent bridge deck just west of the existing M-100 bridge.

That's what motorists will travel over throughout the demolition of the old structure and the creation of the new bridge's support system.

This fall construction crews will use rollers placed under the new bridge deck built just west of the demolished bridge to "slide" the structure into place.

"It is really neat how they do it," said Kari Arend, MDOT Communications Representative. "They use rollers to slide the new bridge back in place. What that allows us to do is still maintain traffic."

Both the bridge and the Thornapple culvert will be replaced by October.

The drains, both built in 1940, are located between Doane and Billwood highways.

Replacement of the Sharp culvert won't start until next April, said Arend.

During the culvert replacements one lane of traffic will be open between Doane and Billwood highways on M-100 with a temporary signal in place.