Supervisors order more inspections on Highway 965 bridge

Drivers crossing the busy Highway 965 bridge over the Iowa River will be stuck with one-lane traffic for the foreseeable future.

The Johnson County Board of Supervisors decided Wednesday it needs more information about the condition of the entire span before it goes ahead with design work and construction to repair the deterioration found on the deck last week.

The board called an emergency meeting May 19 after a road crew and structural engineers found a crack in the southbound portion of the bridge's deck the day before. The board immediately ordered limits on the bridge - decreasing the weight limit to 20 tons and narrowing traffic to one lane with the use of traffic signals.

According to Iowa Department of Transportation figures, about 1,800 cars a day used the bridge in 2014. But Highway 965 is an alternative to Interstate 380 and has been busier since an I-380 span over the river also was restricted during work there.

The Highway 965 bridge's deck was given a 3 rating last week by inspectors, meaning it was in serious condition or had 'many delaminated areas,” according to an Iowa DOT report May 18.

While the crack in the bridge deck was unexpected, Supervisor Pat Harney said that does not mean this situation is necessarily a concern with other county bridges.

'We have the annual bridge inspections that take place,” Harney said. 'There are bridges that need repairs that they're not at the critical level like this one.”

Supervisors asked VJ Engineering, the company already under contract, to move up its inspections of the entire bridge from August to as soon as possible. They said the wanted an up-to-date inspection on the bridge before starting work.

The last inspection of most of the bridge came in 2014 when VJ Engineering found that the deck was rated a 4, meaning it should be replaced in the next three to five years, while the substructure was rated a 7, or in good condition, and the superstructure was rated a 6, or in satisfactory condition.

Tim McDermott, an engineer with VJ Engineering, told the board the underwater portion of the span was last inspected in 2008 by a dive team and looked at again in 2011 when water levels were low. It showed no sign of deterioration, he said.

Supervisor Jenelle Rettig said she wanted all the pieces inspected before considering repairs. Because the engineering company already had inspections scheduled, inspections would not cost the board extra unless the company needs a dive team.

'That just seems to me to be a worthwhile investment,” Rettig said, adding that 2011 'was a long time ago.”

McDermott said that if the rest of the bridge is found in the same condition as 2014, simply replacing the deck should add another 20 years to the life span of the bridge.

McDermott said decks are 'extremely unpredictable” because they go through 'complicated cycles” like salt applications and freeze/thaw processes in the winter.

McDermott said the company is prepared to expedite planning and design of the bridge. Even so, it would be about 45 days before the board could move ahead with choosing a contractor.

'This is extremely aggressive and we've prepared all our people,” McDermott said.

While the board is hoping to get the inspection report on the agenda for next week, there is no overall timeline.

'That all depends on, when the engineers get to looking at it, if they find something else,” Harney said. 'It's going to take some time.”