Another giant hole on I-75 bridge closes lanes

It’ll be another 18 months before the I-75 bridge over the Rouge River in Detroit finally gets the overhaul it so sorely needs – evidenced by yet another gaping pothole that forced the state to close two northbound lanes of the bridge on Monday.

Michigan State Police notified the Michigan Department of Transportation Monday morning that a huge, 3-foot by 5-foot crater had opened up on the center right northbound lane just north of the Fort Street-Schaefer entrance ramp to the nearly 50-year old bridge that carries an average of nearly 103,000 vehicles a day.

The crater emerged just a month after an even bigger pothole – 15 feet by 6 feet – forced emergency repairs to the bridge’s northbound lanes over Dearborn Street.

The two right lanes of the bridge were closed from 8 a.m. to around 4 p.m. Monday, MDOT spokeswoman Diane Cross said. She said crews built a new support frame and poured a quick-drying concrete to fill the pothole.

Cross said the bridge is in need of major repairs, but they won’t come until the spring of 2017. MDOT plans a $100-million project to rebuild the bridge deck and resurface the bridge between Springwells and Fort Street-Schaefer.

“It’s not a complete rebuild,” Cross said. “The structure that holds it up, the piers and all that, is still in good shape.”

MDOT also plans to do additional patching this month, Cross said, to help the bridge get through the next two winters.

The bridge was built in 1967 and was last reconstructed the 1980s, according to MDOT records. The bridge is rated as “structurally deficient,” a term that means its deck, superstructure or substructure is rated in poor condition. Online MDOT reports say the bridge was last inspected in May 2013, when its deck was rated in poor condition, with advanced corrosion, deterioration, cracking, or chipping.

That doesn’t mean it’s unsafe for traffic, Cross said.

“It’s still a safe bridge, and it’s still usable,” Cross said. “If we ever thought for a minute a bridge was unsafe we would close it.”

Cross said bridges rated structurally deficient are inspected more frequently than bridges in better shape.

The I-75 bridge is hardly alone in being labeled deficient. U.S. Department of Transportation data show that 28% of 11,072 bridges in Michigan are considered structurally deficient or functionally obsolete, meaning it’s design is outdated. More than 55% of bridges in Wayne County fall into those categories.

Contact Matt Helms: mhelms@freepress.com or on Twitter: @matthelms.