A historic city bridge is in dire need of repair, and a planned emergency fix only postpones a multimillion-dollar project called necessary to keep the structure passable.

City officials inspecting the Falls Bridge in November discovered corrosion on the support structures beneath the deck, called stringers. The damage was significant enough to lower the bridge's load limit from five tons to three, the lowest load a bridge can bear and still remain open, said David Perri, the city's streets commissioner. An emergency rehabilitation project is planned for January.

The bridge over the Schuylkill in East Falls will need to be closed to cars, but not bikers or pedestrians, during the rehab work, Perri said, and detour routes have yet to be determined.

The bridge is supposed to be limited to passenger vehicles, he said, but some truck drivers occasionally use it as a short cut.

The four- to six-week project will add supports, Perri said, raising the load limit to eight tons. In less than a decade, though, Perri said, he expects structural issues to resurface. The entire deck of the 121-year-old bridge needs replacing, a $6 million undertaking, he said.

The Falls Bridge's woes are part of an issue plaguing the state. Pennsylvania is among the states with the most structurally deficient bridges in the country, about 4,000, according to the state Department of Transportation. For example, Perri said, the Martin Luther King Bridge over the Schuylkill also needs about $6 million in repairs.

"It's all part of the backlog of aging infrastructure in this country that's not being addressed at the federal level," he said.

Of the 3,004 bridges in Philadelphia, Montgomery, Chester, Bucks and Delaware Counties, about 22 percent are structurally deficient, according to the Federal Highway Administration.

The state got $370 million for repairs on locally owned county bridges in the recently passed federal transportation bill, but Perri said it wasn't enough.

Federal regulations require bridges to be inspected every two years, said Eugene Blaum, a spokesman for PennDot. Older bridges or those with known structural deficiencies may be inspected more often. Money is an issue statewide, though the state has made bridge repairs a priority, he said.

"It's a constant effort to get to these bridges for rehabilitation and replacement," he said.

The Falls Bridge, a truss bridge, is both a busy traffic route and a thruway for pedestrians and bikers. A halfway point for people biking or walking in a loop from the Art Museum and back, it's also become a symbol for East Falls.

"We want the bridge to be cared for because it's our landmark," said Gina Snyder, director of the East Falls Development Corp.

In recent years, the bridge has become the site of a September dance held by the organization, Snyder said. The trusses and overhead structure create a sense of intimacy and enclosure, she said.

"It's going to be very, very disruptive of traffic because it's such a critical connection between the two sides of the river there," she said.

The city wants to maintain the bridge, Perri said.

"It's a historic bridge, so it's an asset we don't want to lose," he said. "We do not want to have to completely rebuild the bridge."

215-854-4587@jasmlaughlin