On New Year’s Eve, a developer building a major project on Key Biscayne called Village Mayor Frank Caplan’s office because a cement truck couldn’t make it onto the island. The Ritz-Carlton hotel had trouble getting its dirty linens picked up for laundering. Items thinned out on the Winn-Dixie supermarket shelves. And the island’s two gas stations warned their supply was running low.

“Our commercial traffic was effectively cut off,” Caplan said. “We couldn’t get gas. We couldn’t get food.”

Those were the consequences of weight restrictions imposed on heavy vehicles crossing the bridge linking Key Biscayne with Virginia Key — a short-lived fix attempted by Miami-Dade County at the end of December to deal with severely corroded steel beams supporting the Bear Cut Bridge’s westbound lanes.

But the solution didn’t work. Instead, it resulted in supply shortages that affected everything from package deliveries to moving trucks unable to reach Key Biscayne, according to Caplan. Late Thursday, the county decided instead to entirely shut down the westbound lanes to auto traffic, causing headaches for some commuters Friday morning.

The Florida Department of Transportation had sounded the alarm over the past six months that Bear Cut Bridge required urgent repairs. The county’s public works department began inspecting the bridge every month, removing thick grease protecting the steel to see just how badly the beams, built in 1944 and exposed to saltwater, had deteriorated.

In November, the county notified Key Biscayne about the problem. The next month, public works administrators announced at a village meeting that the county, following FDOT recommendations, would restrict the weight and lanes for heavy vehicles heading west.

Miami-Dade put up signs outlining the weight restrictions and orange plastic delineators — like the ones on the Interstate 95 express lanes — directing trucks onto the inside, westbound lane.

The restrictions went into place and quickly proved unworkable.

By Thursday, the situation was untenable, administrators said. At 5 p.m., the county announced it would close the bridge’s westbound lanes altogether that same night — allowing all traffic, including heavy vehicles, to travel on the two eastbound lanes. One lane would be configured for traffic into Key Biscayne, and the other lane for traffic toward the mainland. At 11 p.m., the westbound lanes were shut down.

Friday morning, the new road arrangement confused cyclists riding on the popular bike lanes. Auto traffic was slow but not at a standstill — though village and county leaders cautioned congestion will worsen Monday, when schools resume following the holiday break.

For now, no one can say how long the lane closures will last. The county, which hired an outside consultant to review the extent of the damage and propose repairs, is still getting a handle on the problems, said Kathleen Woods-Richardson, director of the public works and waste management department.

Based on initial estimates, the project could cost about $25 million, she said, adding that the county plans to “accelerate” the project, given the lane closures.

“We don’t know the extent of it,” she told reporters assembled at the mouth of the bridge Friday afternoon. “We’re confident it’s not a situation where the bridge is going to fall down, but we want to make every effort and be very proactive and make sure we’re doing the right thing.”