Daily News from New York, New York • 287

DAILY NEWS, Sunday. September 24, 1989 KL BS! 1 ff mm M(Mg S) sign reinforcement procedures. Us- (swaying) problem has been eyed by By CHARLES SEATON ing fatigue analysis, officials are try- the TA for the last several decades, ing to design the bridge to take more and officials of the agency's predecessor asked the city DOT to consider moving the tracks to the See SPAN Page 3 of a load from passing rail traffic. "The best way to do it is to allocate the loading and the stresses in three dimensions," said Deitch, who explained that using a computer model would give an accurate reflection of what the bridge goes through each time a subway train passes. He added that the phenomena is visible to the eye.

The Manhattan 'It? 7 -v Bridge's torsional-flex I Daily News Staff Writer THE NEW DECADE rolls Aj near, city commuters are being Atold that completion of structural design and repair work on the Manhattan Bridge is still a decade away. Work projects have suffered massive delays; traffic lanes are periodically closed; subway trains can use only one side of the bridge at any one time, and fresh spots of corrosion, cracks and metal fatigue are uncovered regularly, reports have indicated. In the early part of this month, just days before the mayoral primary, Democratic candidate David Din-kins voiced his concern about the condition of the bridge and used its crumbling roadways and deteriorating structure as issues in his campaign against Mayor Koch. "Is this another Williamsburg Bridge? Is there an imminent danger to the public?" Dinkins asked after pointing out a 10-foot blister on the lower roadway that he believed might signal further structural defects on the giant suspension bridge. Corrosion is cause City Department of Transportation officials responded sharply, telling the Manhattan Borough President that the buckling roadway was not caused by a structural problem, but by corrosion to some of the bridge's steel members, which led to an expansion of the bridge's concrete deck.

They also tried to convince him that there was no danger to the public. Whatever. The Manhattan Bridge is in trouble and everybody knows it especially the tens of thousands of straphangers and motorists who use the bridge daily to cross between Brooklyn's Flatbush Ave. and Canal St in lower Manhattan. Every time a subway train rumbles over it, the bridge twists and flexes and the structure is weakened further, say transportation officials.

It may have seemed a bright idea at the time of its design, but in the 80 years since the suspension bridge was first opened to rail and carriage traffic, the wisdom of placing railroad tracks on the extreme outsides of the bridge has been thrown into question. State Transportation officials said various fixes have been put into place over the decades, but none have worked. "Every time a train goes over, you get stress and stress reversal," explained Ira Deitch, regional structures engineer for the State DOT. "The bridge's design has to be corrected. The primary problem here is the design of the bridge and the placement of the subway tracks on either side." Three-dimensional computer models of the bridge are being used to examine the stress cycles and de- tV" -4 7 jt 1 -kV i -i jj-'rwwsra i' li't''v'i i i 'i I- -a J- REPAm project on Manhattan Bridge nave suffered numerous delays raising concerns aoout span safety.

Above, worwr-ert from American Bridge Company as they toiled on the bridge in 1987. Ri IJNi 1 i 1 A Av.