OCEAN CITY — The tedious process repairing sections of a failing concrete surface on the underbelly of the Route 50 Bridge began this week, forcing single-lane closures that will resume next week.

State Highway Administration (SHA) crews on Tuesday began systematically chipping away at the underside of the Harry Kelley Memorial Bridge, removing chunks, or in many cases, small pieces of failing concrete that run the risk of falling onto vessels below or into the bay. While boaters are supposed to use the navigable channel under the bridge’s draw span, some smaller vessels go under the bridge at various other points.

On Tuesday, SHA crews began working on the project on the eastbound side of the bridge with a large “snooper,” or cherry-picker of sorts, extended over the side of the bridge to provide workers with access to the underneath portion of the span. The work resulted in single-lane closure for much of Tuesday and Wednesday. SHA’s original plan was to complete the entire project in two days this week, but the work proved tedious and crews will return next week to complete the westbound side of the bridge.

“We thought going in it was a two-day job, but it’s a very slow process,” said SHA spokesman David Buck on Wednesday. “They’re looking at every single spot under the bridge where the concrete is chipping away and the first thing they did was look for anything significant. Finding nothing too significant, they started to tackle the smaller pieces literally inch by inch.”

Buck said the bridge’s age was a contributing factor in the patches of failing concrete, and emphasized it wasn’t a structural integrity issue but more of a surface issue. The bridge was built in 1942 and some of its design elements are also contributing to the patches of failing concrete.

“It’s a pretty unique bridge in that it was constructed as a single concrete slab,” he said. “These days, we would never build a bridge as a single concrete slab.”

Buck said most bridges these days are constructed with a catch device system, typically something as simple as a plywood underneath to catch falling concrete and other debris. He said the Route 50 bridge’s design did not allow for a catch device system. Instead, workers are systematically chipping away at small sections of failing concrete with small hammers, often one bucket at a time.

Buck said the SHA crews will return next week to resume the tedious project on the westbound side of the span. Once the work is completed, the underneath side of the bridge will be sprayed with a sealant to prevent future erosion, although that wouldn’t likely happed until after the winter and the freeze-thaw cycles that accompany it.