A portion of the Wando River bridge on Interstate 526 will be blocked early next week — the first of several closures expected amid a critical repair effort that could last another year, state officials said Friday.

A lane on the eastbound side is scheduled to be out of commission starting Sunday night. It's part of a process to permanently shore up the span where a partial shutdown this spring snarled traffic for weeks.

The closure will affect overnight travelers between 9 p.m. and 6 a.m. and will last until Tuesday, the S.C. Department of Transportation said.

The measure comes more than two months after emergency repairs were finished on the twin spans' westbound side, where a primary support cable snapped in mid-May. More permanent work, including the installation of extra cables and waterproofing, might last into next summer, DOT district bridge engineer Kevin Turner said.

The waterproofing of the bridge surface could need more extensive closures. That step is seen as vital since the severed cable was attributed to water-induced corrosion.

"It is by nature slow, tedious work, but it is work that is progressing as well as could be expected," Turner said. "We are considering the impact it will have on traffic and figuring out how to stage and phase that work to minimize the impact."

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Wando River Bridge

Motorists make their way over the James B. Edwards Bridge on Friday, Aug. 17, 2018. State officials on Sunday will close a lane of the Wando River bridge on Interstate 526 amid efforts to permanently shore up the span, whose partial shutdown this spring snarled traffic for weeks. Officials said they plan to eventually open the bridge's truck lanes once permanent repairs are done. Brad Nettles/Staff

Monday is the first day of school in Charleston and Berkeley counties. Negative effects of the first partial closure next week are expected to be minimal during the evening and early morning hours, but a DOT statement said the agency apologizes to motorists "for the inconvenience and appreciates their patience" during the reinforcement operation.

Crews will do electrical work to prepare for the installation of acoustical monitoring equipment, Turner said. The system detects sounds produced by breaks in the steel strands that make up the cables, signaling a potential failure.

Until the equipment is put into place — likely early next year — inspectors will walk through the bridge's cavernous interior and inspect the cables every day, Turner said. Those daily examinations have not revealed any new problem spots, he said.

With I-526 serving as a major link for east-west travelers in the Lowcountry and for traffic to a busy Wando River port terminal, the emergency shutdown this spring prompted gridlock on alternative routes in Mount Pleasant and North Charleston.

The James B. Edwards Bridge has been beleaguered by problems since its opening in 1991 and the cable failure raised questions about its safety and long-term outlook. The DOT had already spent $3.8 million on fixes and investigations related to the cables before this year's problem emerged. With concrete segments linked by cables that are susceptible to corrosion, similarly designed bridges elsewhere in the country have suffered the same problems.

Workers added two new cables to the westbound side during the emergency shutdown. Since it reopened June 2, they have replaced the one that ruptured, Turner said.

Eventually, the engineer said, two backup cables will be added to the eastbound side as well, probably in the first quarter of 2019.

"Over the next several months and into next summer," Turner said, "you'll see us moving back and forth between the bridges and performing repairs in the order that they're needed."

Crews mostly operate out of sight below the bridge deck but they have kept the two truck lanes on the six-lane bridge closed to help in the effort. The truck lanes were closed before the shutdown, though, because of a previous effort to fix another damaged cable found in 2016. That step was needed to alleviate the potential stress caused by heavy construction equipment, Turner said.

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Wando River bridge 2016 failed cable

A cable in the westbound Wand River bridge on Interstate 526 failed in 2016, prompting repairs and lane closures. Another failed in 2018, sparking an emergency shutdown of the entire westbound span. S.C. Department of Transportation/Provided

The loss of the truck lane has little effect on traffic, causing about as much of a slowdown as the merging of trucks back into the regular travel lanes, Turner added. But the long-term plan is to reopen the lanes: the westbound side later this year and the eastbound span early next year, he said.

Officials on Friday continued to stress that the bridge is safe.

The DOT is still trying to find the right acoustical monitoring system, Turner said. In the meantime, he said, new video cameras and microphones already have given inspectors some remote monitoring capabilities.

"We have the ability to see and hear what’s going on in the structure at any point in time," he said.

Reach Andrew Knapp at 843-937-5414. Follow him on Twitter @offlede.

Andrew Knapp is editor of the Quick Response Team, which covers crime, courts and breaking news. He previously worked as a reporter and copy editor at Florida Today, Newsday and Bangor (Maine) Daily News. He enjoys golf, weather and fatherhood.