Daily News from New York, New York • 537

fisr si ky mm DAILY NEWS VNJ-J JSA. Sunday. March 19, 1989 figs. -fy? f-l-l, i PELHAM PARKWAY Bridge over Eastchester Bay in the Bronx gets inspection by diver-engineers from the Department of Transportation. By GUS PALLAS Daily News Staff Writer $-short rush to stiffen spans before they fall nHE COLLAPSE of a bridge near II Mobile, on April 24, 1985, sent ripples all the way to New York State, which rushed divers to in-I spect underwater bridge supports that had not been checked in more than five years.

The Schoharie Creek Bridge, near upstate Amsterdam, was one of 300 bridges inspected. But murky water hid the underpinnings, and a second check was ordered. Before that was done, the bridge collapsed on April 5, 1986 drowning 10 persons. What the first diver had not been able to see was that two underwater supports had been undermined by the creek's flow. The Legislature then ordered that every municipality immediately inspect all bridges whose submerged supports had not been looked at for five years.

ed, emphatically, that there is still a big safety margin. For example, he said, bridges may be designed to take stresses of 25,000 pounds per square inch, but the steel in the bridge will be capable of resisting 50,000 pounds per square inch. Hearing him, Schwartz smiled, agreeing but adding: "George is the optimist, I'm the worrier. If we mistreat our modern bridges, they will go down. "My concern is that over time, even steel that is uncleaned and untended deteriorates.

Modern bridges are strong but have no redundancy (duplicated members for safety's sake). In older bridges, if one member goes, another member picks up the load, but you don't find that in modern structures." If a cable on the Williamsburg Bridge breaks, the other cables may not support its load, he said by way of example without suggesting that there is danger of such a cable break. The Williamsburg Bridge is being redesigned even as repairs are underway, and main cables will be connected to trusses that would take a sudden extra load, he said. The four main cables are to be replaced by stronger, ones, Schwartz said. A third of the suspender cables have already been replaced, major pier-foundation repairs and other emergency repairs have been-made, the outer roadway has been replaced and the sides and towers have been repainted.

Still under design are new main cables, new approaches and the main bridge Total cost of the Wily marked in the fiscal 1988 budget to hire 35 bridge inspectors, enlarging a crew of three that existed at that time. Diver-engineers were hired from a private firm, and inspectors checked the submerged structures of 27 city-owned bridges that had not been inspected for at least five years. They found that 21 needed minor repairs underwater, and that one needed extensive repairs. But none was in hazardous condition, and nothing was even remotely close to a Schoharie Creek situation, according to Transportation Commissioner Ross Sandler. Sandler said that eight of the inspected bridges will be repaired by the department's own crews within two years.

Four others will be fixed by outside contractors within three years, and the rest will be fixed as soon as possible, he said. A face lift A cracked and displaced concrete abutment was discovered under the Hylan Blvd. bridge over Lemon Creek in Staten Island. The damage was so serious that the bridge will be rebuilt, Schwartz said. Bids will be put out in May for a $2.9 million reconstruction of the span, which carries 10,700 vehicles a day were built: the Terrace Bridge in Prospect Park, built in 1890, and the East Tremont Ave.

Bridge in the Bronx, built in 1897. The Terrace Bridge, which carries Hill Drive traffic over the Lull Water part of Prospect Lake, is maintained by the Department of Parks and Recreation. The department plans a $1.42 million face lift for the elderly span. It will include new steel beams in the substructure, new bricks, cast-iron grilles and balustrades, and landscaping and replanting around it Water has eroded piling bases under the East Tremont Bridge. But filling in the gaps is a minor repair, according to George Zandalasini, the department's deputy director for engineering management He remarked, with engineer's pride, that the city's older bridges are standing nicely because bridge-builders at the turn of the century built very well with the materials they had.

"If anything, they overbuilt for safety," he said. "They just couldn't imagine the stress and wear their works would suffer under the traffic of the future." Today's bridge-makers use alloy steels and high-strength materials that allow them to figure exactly how strong a particular bridge should be, he 5 i juj iiit In New York City, the East River bridges are inspected as often as twice a year. But they still fall apart when there is no money to fix them, according to Samuel Schwartz, the Transportation Department's first deputy commissioner. Knowing problem spots is nice but doesn't help much when money to maintain and repair bridges was cut off about 10 years ago to help repair the city's fiscal crisis, Schwartz observed. The ripples from the Schoharie tragedy shifted the tide and Mayor Koch 'sirddenrv ffttihd tndne in the The 27" inspected bridges included capital MghJp'ribrity Irt- 'two 'ancient crossings that" -had' not'But we'lfave td-lceep liathsburg reconstruction ts'-esWmated'.