For the second time in 20 years, corrosion to support cables known as “tendons” has forced the Florida Department of Transportation to close the busy Mid-Bay Bridge for emergency repairs.
FDOT spokesman Ian Satter confirmed Wednesday the corrosion that caused this year’s closure “sounds similar” to what had previously occurred.
He could offer no timetable for when the latest repairs would be completed and the bridge reopened to traffic. The Okaloosa County Sheriff’s Office reported it had been informed the shutdown could last “a couple of weeks.”
In 2000 the bridge was closed for all or part of 25 days and cost the bridge owner, the Mid-Bay Bridge Authority, $6 million in repairs and lost toll revenues.
Bridge Authority Executive Director Van Fuller referred questions about the most recent closure to the FDOT.
“I hope we can get it open as soon as possible,” he said. “It’s an important transportation corridor, but what is most important is the safety of the traveling public.”
The Sheriff’s Office has reacted to the closure by splitting its District 3 — which covers Destin, Okaloosa Island, Valparaiso and Niceville — into two zones, north and south of the Choctawhatchee Bay, said agency Maj. Eric Aden. Valparaiso and Niceville-assigned personnel will report out of the Sheriff’s Office headquarters in Shalimar until the bridge is reopened.
“We have augmented with state DOT for traffic control with message or sign boards for directions to citizens,” Aden said. “These signs are located throughout the county in strategic locations to assist with the flow of traffic.”
The County EMS is stationing two transport vehicles in Destin 24 hours per day and a third during the highest call-volume shift of the day in order to balance out the effects of the closure of the bridge.
“We are all hands on deck for this emergency,” an EMS official said.
The Okaloosa County School District issued a statement Tuesday evening stating it was working on alternative bus routes and transportation.
District officials failed on Wednesday, however, to provide the alternative routes when requested by the Northwest Florida Daily News. School Board Chairman Lamar White said he had spoken to district transportation personnel but late in the day had no information about what plans had been made to respond to the bridge closing.
“I don’t know where we are with that,” he said.
The latest signs of corrosion were first noted during a routine bi-annual FDOT inspection conducted late last year, according to Satter. The Bridge Authority conducts its own inspections in years that FDOT, which operates and maintains the bridge, does not.
"During our inspection in October, they found some tendons they wanted to replace as part of maintenance … all bridges need maintenance,” he said. “Then we had Hurricane Michael come through (Oct. 10) and we had to focus attention on recovery.”
Satter said the bridge was determined to be safe to drive upon and, as hurricane recovery efforts were ongoing, FDOT assembled a team to go inside the Mid-Bay Bridge and complete the required maintenance.
“They went in one more time for an inspection and were in there this week and saw the corrosion was a bit further along than they were comfortable with,” Satter said. “That’s why they decided to close the bridge.”
Crews were sent in Tuesday night after the bridge was ordered closed and 15 to 20 people were sent back into the guts of the bridge Wednesday to assess the damage, Satter said. They are studying repair options before bringing in the materials needed to complete the work.
Traylor Construction Co. built the Mid-Bay Bridge in 1993 under the supervision of Figg Engineering Group, its designer. The first corrosion was found just seven years after its completion.
An investigation conducted in the aftermath of the 2000 closures blamed the corrosion on sloppy construction and the use of inadequate materials. A more comprehensive study completed in 2001 found 41 bridges in Florida with corroded cables, leaks or cracks.
The Mid-Bay Bridge Authority’s governing board considered suing Traylor Construction and/or Figg Engineering after the report citing sloppy construction was made public.
Figg Engineering did not respond Wednesday to a request for comment.
Asked if there were other bridges in the state in which corroded tendons were found 20 years apart, Satter said the amount of maintenance required varies from bridge to bridge.
“It depends on the structure, the age, the condition,” he said. “Obviously we live in an area where, along the water, there’s a high concentration of salt water."
The six tendons that help support the Mid-Bay Bridge are all coated with a protective cover and sealed, Satter said. “But if there’s any way water can find its way in it will.”
He could not confirm that exposure to the salt air or water had caused the corrosion discovered in October.
“We’re determining how it happened and more importantly how we can fix it,” he said. “We’re trying to get the repairs in place.”
Satter said corrosion was originally noted in one tendon and more recently discovered to have damaged a second.
In 2000, the bridge was originally closed on Aug. 28-29 when corrosion was discovered. One tendon was found so badly corroded it had “failed” and was found lying on the ground in the cavity beneath the bridge roadway.
An extensive inspection that followed the original repair efforts found 11 more damaged tendons. The bridge was closed for several more days in September and October as repairs took place.
The corrosion that caused the damage formed on the tendons when water pooled in air pockets that formed in the grouting used to encase them, investigators said in their 2001 report.
They said the grout surrounding the steel tendons was “of suspect quality in many areas of the bridge.”
The investigation also found evidence that polyethylene ducts used to seal tendon ends “did not meet the requirements of the construction specifications.”