A weekend-long bridge slide reduced construction delays and opened the road back to traffic after one weekend closure on the Michigan Department of Transportation's M-100 bridge improvement project in Potterville, outside of Lansing.

"The replacement of the existing bridge was necessary due to the advanced deterioration of the existing structure," says Greg Losch, Construction Engineer with MDOT.

The $8.6 million project included replacing three bridges: one over the Canadian National/Grand Truck Western Railroad, another over the Thornapple Drain and a third over the Sharp Drain. The existing drains were built in 1940 and were 40-foot-wide.

The new bridges will reduce maintenance costs and improve safety and pedestrian facilities. About 5,400 vehicles use the bridges daily. Davis Construction of Lansing began construction in March 2015.

Railroad Bridge Slide

The three-span, 157-foot ling, 40-foot-wide M-100 bridge over the Canadian National/Grand Truck Western Railroad was constructed in 1940. It had two 11-foot lanes with 9-foot shoulders. The existing bridge was relatively narrow.

"This did not provide adequate room to maintain two lanes of traffic during construction without temporarily widening the bridge," Losch explains. "The existing bridge had a steel bent cap. This made construction of the project using part-width construction extremely challenging."

Faced with no good options for a detour, the need for emergency vehicles to use the bridge and 32 trains running beneath it every day, MDOT officials decided to use a bridge slide to replace the structure. The new bridge has two 12-foot lanes, 10-foot shoulders and a 10-foot pedestrian path. It was only the fourth time MDOT had slid a bridge into place.

"This project was the first in Michigan to utilize high capacity rollers to move the proposed superstructure into place," Losch says. "This project was the first in Michigan to utilize a lateral bridge slide over a railroad."

Davis Construction built a temporary road with the new single-span, steel-girder bridge about 76 feet to the west of M-100, and starting in August 2015, two lanes of traffic flowed effortlessly on that. The contractor also lengthened the existing pedestrian tunnel, so safe access could be maintained to and from a school located near the project.

The temporary substructure considered of two rows of 14 piles, with the frame braced in each direction and field welded. A longitudinal triple W 18 by 76 beam carried the main load. MSE walls were built using the frames to retain the road fills.

Once complete, traffic shifted to the new bridge, at the temporary location, while crews demolished the old bridge and built full-height concrete abutments on steel H-piles, wide enough to accommodate the new structure, and new wider approach roadways to the bridge. The project was closely coordinated with CN Railroad through the MDOT Office of Rail. MDOT staff completed a railroad safety program, and a flagman was on site throughout construction to warn the contractor of approaching trains.

"Both the existing and proposed bridges had a significant skew due to the angle of crossing between M-100 and the CN tracks," Losch says. "There were concerns that this may have complicated the lateral bridge slide operations."

But it went smoothly. The slide took place on a cold November night. Crews used a Hilman Roller, with two pushing cylinders, to move the 524-ton superstructure 96 feet into place. The vertical jacks had a capacity of 100 tons and the horizontal jacks 32 tons. 

"There was excitement," Losch says. "There was anxiety because of the known challenges and because of the realization that it would be a tight fit between the new return walls."

The contractor's power source and control unit for the jacks used to lift and move the superstructure was located on the bridge. The person operating the system was located on the bridge the entire time. The contractor had a surveyor on site throughout the lateral bridge slide. Measurements were taken after each push cycle to ensure the superstructure was on track.

The slide was complete on November 15, 2015, with trains continuing to run under the bridge. It took 18 tons of force to move the bridge into place.

The company finished the actual sliding of the bridge into place and pouring the approaches with early-strength concrete in one weekend. The road opened to traffic on the following Monday. Losch says he is proud of the team effort it took to complete the project.

"The project showed that using high capacity rollers was a viable option for lateral bridge slides in Michigan, and that in some respects they worked better than the methods used on previous lateral bridge slides," Losch concludes. I'm also proud of "the innovation in one project to combine newer bridge construction methods on each of the structures." 

Drain Bridges

The department used a composite bridge system on the bridge over the Thornapple Drain, completed last year. The composite exoskeleton is comprised of curved composite arches, filled with concrete and supported by concrete footings. Composite decking tops the exoskeleton and gravel fill has been placed above that.

For the Sharp Drain bridge, the department used a concrete box beam with prestressed carbon fiber reinforcement. Construction will wrap up on it this fall.

 Family-owned Davis Construction was founded in 1970 and has grown to include operating facilities in Lansing and Grand Rapid, Michigan, and Decatur, Texas. The company tackles projects of all sizes and welcomes challenging jobs with difficult site conditions or fixed budgets. Davis specializes in bridges, including complicated civil projects.