TROUBLED BRIDGES. Inspectors bear an increasing public-safety burden, as once-grand structures yield to stress, rust, and decay
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Surrounded by piles of broken bridge machinery stored beneath the Third Avenue Bridge, Bokman explains that water has seeped into the bearings and corroded the deck support beams and substructure. He notes that salt - sprayed up from the Harlem River and spread on the roadway to melt snow - has also eaten into structural steel members. Though the bridge was painted recently, the decay was either ignored or undetected.Skip to next paragraph
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``All the paint did was hide the defects,'' he says. ``It didn't protect anything.''
Bokman predicts the bridge will be given an overall structural integrity rating of 3 on the scale of 1 to 7, with 1 meaning ``potentially hazardous,'' and 7 meaning ``new condition.'' A 3 means that the bridge, which serves more than 128,000 vehicles daily, has experienced ``serious deterioration.''
Forty-eight people died in the 1967 collapse of the Silver Bridge into the Ohio River. The fatalities alerted the nation to the condition of its bridges, and set in motion the creation of a ``national bridge inspection standard.'' In the mid-1970s the federal government mandated that each municipality use this standard to inspect all its bridges on a two-year cycle.
The inspectors combing the Third Avenue Bridge and the 19,501 other bridges scattered across New York State bring similar backgrounds to their task. All have a minimum of a civil engineering degree and three years of bridge-related experience. Many are professional engineers who worked in bridge design or maintenance before becoming bridge inspectors.
To attain their present jobs, they must complete a one-week training course offered by the New York State Transportation Department. The starting salary for a state-employed bridge inspector is $29,256.
According to John Mladinov, executive deputy commissioner of the state transportation department, 26 employee teams and 35 consulting teams are each responsible for inspecting between 100 to 200 bridges annually. In New York, the state is charged with inspecting city-owned bridges, while the city maintains them.
The Road Information Program (TRIP), a nonprofit organization that evaluates highway transportation issues, says the national bridge inspection program is generally effective, despite its estimates that 150 bridges buckle or collapse each year. TRIP says 4,125 bridges nationwide are closed to traffic.
Some New York City bridges, such as the North Channel Bridge connecting Howard Beach and the Rockaways in Queens, are so badly deteriorated that they are beyond saving. It will cost $70 million to replace the North Channel Bridge, according to the city's transportation department. The Williamsburg Bridge Technical Advisory Committee is due to report by July 1 whether that bridge should be salvaged at a cost of $250 million, or scrapped and replaced at a considerably higher price.
Flaking concrete, holes in the roadway, and heavily corroded steel stringers have forced the closing of two lanes on the Queensboro Bridge. This bridge, which carries the most traffic of the four major East River crossings, has the worst structural problems of any New York bridge, according to Mr. Mladinov of the state's transportation department.
Just as other New York crossings are in worse shape than the Third Avenue Bridge, other states lead New York in the number of deficient bridges more than 20 feet in length, according to the FHWA. Texas tops the nation, with 15,450 deficient bridges, while New York ranks sixth, with 11,726.
Yet according to John Alskog of the FHWA, the eyes of the nation's engineering community remain riveted on New York's engineers as they rush to perform triage on the city's bridges. Mr. Alskog maintains that age has ravaged the bridges. According to TRIP, 38 percent of the bridges have surpassed an average life expectancy of 50 years.
Noting that the 1950s and '60s were years of new highway bridge construction, Alskog concludes that in the coming decades, other states will experience the troubles besetting New York.
``Because the bridge population is not evenly distributed with regard to age, we're concerned that during the next 20 years we will encounter a very serious bridge problem, requiring heavy rehabilitation and reconstruction,'' he says. ``We'll need our best engineering and managerial skills to face this problem.''
Manny Beiglemacher, supervisor of the state's bridge inventory and inspection program for the New York City area, likens inspecting to investigative work. ``We're detectives out here, trying to discover and understand what's going on.''
As a dark rain begins to fall on the Third Avenue Bridge, he adds softly, ``We're well aware that the burden of the public's safety falls on the inspector.''