A routine inspection Friday revealed a 20-foot-plus crack in the Grand Boulevard Bridge over Interstate 670, prompting its immediate closing and raising concerns that it would need to be replaced.
“I think we’re going to lose the bridge,” said Brian Kidwell, the assistant district engineer in Kansas City for the Missouri Department of Transportation.
Officials planned through the day Friday to shore up the bridge, where concrete was crumbling off a section just south of the pillars that divide I-670. That prompted the temporary closing of a lane on the interstate and a nearby Interstate 35 on ramp.
But Kidwell said the bridge looks to be in need of serious repairs or replacement. It was built in 1963.
The four-lane, north-south bridge is a sonovoid design, meaning it was made by pouring concrete around forms that leave large empty tubes inside to reduce its weight. Kidwell said it appears water may have seeped into that interior and frozen during the winter.
Seen from the east, the zig-zag crack is 25 feet long, Kidwell estimated.
“It starts big and just keeps going,” he said.
The “major delamination,” concrete flaking away from the bridge in cantelope-sized chunks, posed a threat to drivers underneath. So MoDOT planned to put up temporary supports for the bridge on what had served as the left shoulder of eastbound I-670. It also plans to erect a barrier to keep falling concrete away from the interstate.
Crews had shut off all traffic — for cars and pedestrians — above on Grand Boulevard from 15th Street to Truman Road just south of the Sprint Center at midday. By early afternoon, the foot traffic was open, but cars will be kept off Grand indefinitely.
MoDOT spokeswoman Kerri Lewis kept open the possibility the bridge might be replaced. She said engineers need to learn more before estimating the cost of any fix. She said it was also unclear whether Grand might ultimately reopen while repairs were made.
To make way for the streetcar line that opened the same day the Grand bridge closed, Kansas City spent about $2.75 million for a new three-lane bridge over the same interstate at Main Street. That included sidewalks, lighting and decorative fencing. It’s unclear if that price would translate to the cost of a Grand Boulevard Bridge replacement.
The Grand bridge had passed a thorough inspection in September. Follow-up inspections in recent months discovered the crack, but the severity of the damage wasn’t detected until Friday.
Kidwell pointed to clean concrete on the left shoulder of the highway below and several feet of exposed rebar on the bridge’s underside that had not rusted. Both, he said, were evidence that the damage was fresh and happening faster.
Traffic on surface streets in downtown was being rerouted around the closed bridge. For drivers heading south on Grand, the detour runs from 12th Street to Oak Street to 18th Street. For those headed north on Grand, the route goes from 18th to Oak to 13th Street.
Updates will be posted on MoDOT’s website.
The Star’s Lynn Horsley contributed to this report.