The closing of the Spring Avenue bridge in Troy last month came suddenly, but such shutdowns could become commonplace in the years ahead.

More than a third of the Capital Region's bridges are rated as being in less than good condition, but the funds to fix or replace them are drying up. It's not the most commonly traveled ones that are in jeopardy, but the locally owned spans vital to communities that can ill afford to maintain them.

In his five years as Rensselaer County engineer, Wayne Bonesteel had never before had to close a bridge — until now. This year, he had to shut down three. With insufficient money for repairs and replacement, he said, "we could see four to five more bridges close in the next 10 years."

Bridges, whether maintained by the state or a locality, are inspected at least once every two years by the state Department of Transportation, and a rating of 5 means a span is in good condition.

Of the 950 bridges in the Capital Region, 350 ranked below a 5, a review of federal and state highway data conducted by the Times Union shows. Using the data, the newspaper ranked the 10 bridges in worst condition in Albany, Saratoga, Rensselaer, and Schenectady counties. More than half the region's bridges are state-owned, though the ones in worst condition tend to be owned by counties, towns, cities and railroads.

"Cities owning bridges are just asking for trouble," Rensselaer Mayor Dan Dwyer said. "It's tough to get funding, very, very tough. There is so much allocated and for small cities, it's really competitive."

In the past decade, as these bridges have deteriorated, the amount available to fix area roads and bridges has been slashed by $100 million, the Capital District Transportation Committee says. Its new panel on bridges will hire a structural engineer to review all spans owned by counties, cities and towns to determine where to spend limited funds,

"When you don't have a lot of money, you want to spend it in the most effective way you can," said Director Michael Franchini.

Three of the 10 worst bridges in the region are owned by Rensselaer County. Of the three bridges closed this year, one was fixed, one is slated to be done in 2014 and one remains in limbo for lack of funds. One, on County Road 111 in Johnsonville, was built in 1891, is considered historic and can't legally be demolished. The county plans to restore it for pedestrian use, move it and build a new bridge where it now stands.

The county had planned work on five other spans but Bonesteel says it will lose funds as the state, which distributes federal highway funds, shifts to stress preservation over replacement. Rensselaer County owns and maintains 60 bridges with an average age of 51 years, though many date from the 1930s.

"We have always had to rely on the federal aid funding because the cost to replace a bridge is so great," Bonesteel said.

The county has only $60,000 in local funds for maintaining bridges. Renovations needed to a bridge on County Road 15 this year cost $45,000.

"That pretty much ate up our budget," said Joseph Teliska, deputy highway engineer.

Sam Zhou, state Department of Transportation regional director, said the Capital Region is filled with "baby boomer bridges" built in the 1950s and 1960s. Like their human counterparts, they're growing older and less healthy.

"Transportation money is mainly from the gasoline tax," Zhou said. "Vehicles are more efficient, so the gas tax can't keep up. The department has dramatically shifted to a preservation strategy."

Some gas tax funds are available for new projects, but some are dedicated to repaying bonds on work already done.

In the past two years, the state has increased its investment in improving roads and bridges. Under its NY Works program, $488 million in such improvements were made in 2013, compared with $462 million worth in 2012. The improvements better preserve the state's infrastructure and guard against the need for more costly, in-depth construction. A total of 57 bridge projects statewide were completed through NY Works this year, compared to 45 projects in 2012.

Starting next fiscal year, which begins Oct. 1, the state will spend 83 percent of the highway funds it distributes to municipalities on keeping existing bridges and roads functional rather than replacing them, Zhou said: "Major reconstruction will be reduced."

Beau Duffy, a spokesman for the statewide department, said it's not that sharp a distinction. Work like replacing the decks and supporting girders on the Twin Bridges is preservation work, not replacement, as is redoing much of the Patroon Island Bridge. Even if many of a bridge's components are replaced, he said, it still counts as preservation.

For local governments, keeping their bridges in good shape is a tough challenge in tight fiscal times. The state owns only three of the bridges in the Capital Region's bottom 10, and work on them is either done or under way, as local governments struggle to find the funds for their aging infrastructure.

Zhou said the public needs to press for more funds to maintain and replace the aging spans.

"The important message to the public is 'Don't take it for granted,' " he said. "... We need infrastructure investment so we don't end up closing bridges like the Spring Avenue bridge."

In Troy, the city knew the Spring Avenue Bridge was in rough shape and was already planning to replace it, City Engineer Russ Reeves said. Built in 1940, the bridge had a condition rating of 2.727.

"We were a little bit surprised at the speed with which some of the corrosion had advanced," he said. He blames a rainy winter last year, which combined with heavy salting of roads, speeded up the deterioration.

A second bridge in Troy also was briefly closed last month. A cracked I-beam was found on the 126th Street Bridge during a routine inspection, but the state DOT was able to quickly install cables to take the load. "They are stronger than the original," Zhou said. "Luckily we were able to do it quickly." The repair cost $25,000 and should last until the bridge undergoes a major rehabilitation in the next five years.

More Information The 10 Worst Bridges Here are the 10 bridges with the worst condition ratings in the Capital Region, according to the most recent state data. 1. Spring Avenue Bridge, Troy: Now closed. Rated Structurally Deficient. Condition Rating: 2.727. Closed, to be replaced. 2. Second Avenue Bridge, Rensselaer: Structurally Deficient. Condition Rating: 3.265. 3. Oak Street railroad bridge, Schenectady: Structurally Deficient. Condition Rating: 3.292. 4. Dayfoot Road Bridge, Petersburg: Structurally Deficient. Condition Rating: 3.375. 5. Interstate 90 and Route 150, Schodack: Actually two bridges, both structurally deficient. One has a condition rating of 3.517, the other a 3.621. The state has replaced one of the two spans, the other is set for replacement next year. 6.County Road 111 Bridge, Johnsonville: Structurally Deficient. Condition Rating: 3.531. Now closed, will be moved, restored for pedestrians only, and replaced. 7. The Rexford Bridge, between Clifton Park and Niskayuna: Not rated deficient or obsolete. Condition Rating: 3.547. 8. Route 67 Railroad Bridge, Mechanicville: Structurally Deficient. Condition Rating: 3.558. 9. Black River Road Bridge, Stephentown: Structurally Deficient. Condition Rating: 3.587. 10. East Road Bridge, Stephentown: Structurally Deficient. Condition Rating: 3.627. Capital Region Bridge Facts Number of bridges in Capital Region 950 Number rated functionally obsolete 232 Number rated structurally deficient 110 Number rated below 5 350 (which means good condition) See More Collapse

Troy has seen some of its other spans, like the Collar City and Congress Street bridges, redone by the state. With 26 bridges in the city, Reeves said, crews will try to make maintaining them part of a daily routine. To prevent corrosion, he said, steel supports will be washed free of road salt each spring and summer.

The federal government has two different bridge measures, both of which sound at first blush as if a bridge's condition is more dangerous that it may be.

A functionally obsolete bridge, of which the region has 232, are ones whose designs are outdated. If built today, they would be made differently but that doesn't mean they are necessarily dangerous.

The other term used, "structurally deficient," sounds more alarming, but it means at least one of its components has a weakness that may be fixable.

"It doesn't mean those components are in horrible condition," said Richard Marchione, director of the DOT's Office of Structures that oversees bridges statewide. "If there is some deterioration to a girder, even if it's capable of bearing the load, you want to address it before it becomes an issue."

The Capital Region has 110 bridges listed as structurally deficient.

There are 47 components that are rated to determine a bridge's condition, Marchione said.

"It's basically a weighted average of the components of the bridge," he said.

In the last two years, the state has been able to infuse more money into bridge repair in the region under its NY Works program, but that funding boost is about to dry up.

Over the last five years, the state's Region 1 has spent $64 million on bridge repairs and replacements. "New York Works has definitely given a shot in the arm to the Capital Region," Zhou said. "We did 110 bridge decks (statewide)."

The Twin Bridges, Patroon Bridge, Western Gateway and Congress Street bridges were repaired under the program. Other state funds went to fix the Troy-Menands, Dunn Memorial, 787 viaduct, and the I-90 and Route 150 bridges in Schodack.

The latter bridge — actually listed as two bridges, one in each direction — comes up twice in the rankings of the worst spans in the Capital Region. This year, the state began a two-year project to replace the bridges. The eastbound span was replaced this summer; the westbound span will be done next year.

The state also has plans to replace the Rexford bridge, which also made the bottom 10 list, with options to be presented to the public in early 2014.

When the state decides which bridges to fix or replace, the condition rating is one factor, Zhou said. Others include the traffic volume, its importance for commuters or businesses or to get produce to market. "It's not necessarily just volume," he said. "It's the function it serves to the community."

Staff Research Director Sarah Hinman contributed to the reporting of this story.

tobrien@timesunion.com • 518-454-5092 • @timobrientu