Innovative M-86 bridge reconstruction over Prairie River in Centreville starts July 18

Contact: Nick Schirripa, MDOT Office of Communications
 schirripan@michigan.gov
269-337-3927
Agency: Transportation

Fast facts:
- The new M-86 bridge over the Prairie River will feature two innovations: carbon fiber reinforcements, a first in the state, and one of only two bridges in the state with concrete bulb T-beams.
- The current M-86 bridge, a historic camelback pony truss bridge, is being restored and relocated to the local road system in Cass County.
- The $4.9 million investment includes constructing the new bridge from July to November 2016, and restoring and relocating the original bridge from July 2016 to September 2017.

July 7, 2016 -- On July 18, the Michigan Department of Transportation (MDOT) will begin removing the historic M-86 bridge over the Prairie River east of Centreville, St. Joseph County. Completion of this $4.9 million investment is expected in November.

MDOT will remove, restore and, in 2017, relocate the historic truss bridge 50 miles away to Crystal Springs Street over the Dowagiac River, near the intersection of Crystal Springs Street and Wood Road in Pokagon Township, Cass County.

The new, 104-foot M-86 bridge over the Prairie River will be the first MDOT bridge to use carbon fiber composite strand reinforcement in the bulb T-beams. The carbon fiber strands will provide many benefits, as it is non-corrosive and lightweight, yet still has high tensile strength, which will extend the service life of the bridge by 25 years or more. The concrete beams will be monitored to compare their longevity to beams with traditional reinforcement of other new bridges elsewhere in the state.

Read more about carbon fiber composite cables on MDOT’s website at www.michigan.gov/documents/mdot/MDOT_Spotlight_CFCC_469162_7.pdf.

The new M-86 bridge also will be one of only two bridges in the state to feature an innovative design – concrete bulb T-beam – that, when paired with the carbon fiber reinforcement, is expected to help reduce the concrete cracking, deterioration and corrosion typical in traditional steel-reinforced bridges. By implementing these innovative designs, the new bridge beams could last more than 100 years and require less maintenance, leading to significant cost savings for Michigan taxpayers.

Read more about concrete bulb T-beam bridges on MDOT’s website at www.michigan.gov/documents/mdot/Project_Update_pooled_fund_T_beam_WEB_1-11-13_408048_7.pdf.

Part of this project also includes repairing and relocating the existing bridge over M-86. The camelback pony truss structure was originally built in 1923 on Telegraph Road over the Rouge River in Detroit. The bridge was moved to its current location in 1938 under the Public Works Administration program.

The historic truss is the last remaining of its type on the state trunkline system in Michigan, and is required to be preserved. Although it is too narrow for the traffic volume of M-86, the lower traffic volume on Crystal Springs Road makes that area an ideal location. The restoration will include replacing portions of the rusted steel and then painting the entire truss. To preserve the historic elements of the bridge, more than 1,800 rivets will be required to reassemble the truss elements. The relocation project is expected to be completed by late September 2017.

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