Daily News from New York, New York • 343

Riday. DecefnbrjJ8, 987 i QAILY NEWS: ii UULo)LTU(oj I i it By SUSAN MILUGAN and RICHARD SISK Daly News Staff Writers Major cracks found in lower level roadway of yesterday forced the shutdown of another lane ot trattic over the deteriorating and poorly designed span. "It certainly is a critical situation or we MANHATTAN i Vl WILLIAMSBURG Jl I MANHA TTAN I BRIDGE I 11 5s- WORKMEN REPAIR major cracks in beams supporting the Manhattan Bridge. Circle, inset, shows location of cracks in the floor beams; below, the areas of the bridge under repair. Four of the seven traffic lanes of the bridge remain open.

n. beams suDDortine the the Manhattan Bridee wouldn't be closing a traffic lane in the holiday season," said First Deputy Transportation Commissioner Samuel Schwartz. He added: "There's no danger as long as we keep traffic off the lane," which is the left Manhattan-bound lane. The cracks, ranging from a few inches to 15 inches in length, were found in 20 of the 80 floor beams that support three lanes of the lower roadway along the span between the two bridge towers. The beams are Bach 37 inches thick.

The cracks were first noticed in far less pronounced form in 1984 and technicians drilled holes near them in an attempt to arrest deterioration, Schwartz said. A routine inspection Wednesday disclosed that the effort had failed and that the cracks had worsened significantly, Schwartz said. New repairs, expected to take about a month, will begin after engineers assess the. scope of the project today, he said. Mass transit urged While the lane is out of service, "It will take drivers a long time to get across the bridge.

I recommend public transit," Schwartz said. In addtion to the closure of the lane, Manhattan-bound trucks are banned from the bridge, and the Transit Authority's B51 bus service between Brooklyn Heights and Manhattan, serving 1,900 daily passengers, will be discontinued until the lane is opened again. A TA spokesman said the buses cannot use the Brooklyn Bridge because of inadequate height clearances. The closing of another lane of traffic, the third of seven to be closed, highlighted the problems in repairing the bridge because of the "erratic design" of the 84-year-old span, said a spokesman for the state Department of Transportation, which is overseeing the $150 million rehabilitation project. City and state engineers are at a loss to explain why the original designers chose to run subway tracks along the upriver and downriver edges of.

the bridge, rather, than down the center of the as a result, suoway trains passing over the bridge cause a "twisting" motion along the span, placing added strain on the cables. Two tracks shut The. heaviest strain is on the upriver main cable, which is currently undergoing repairs' that previously forced the shutdown of two subway tracks on the upriver side of the bridge and the two lanes of traffic that run above them. George Zandelasini, a city Transportation engineer, said that the problems of the cables and the floor beams were not related. A "thinning-out effect" from the combination of corrosion and the weight of traffic led to the cracks in the floor beams, Zandelasini said.

Foster Beach 3d, regional director of. the state Transportation Department, said the first step in the beam project will be to erect platforms under the roadway from which ironworkers could repair the cracks. The workers will weld and bolt a total of 44 metal plates to both sides of the cracks to add strength to the 37-inch-' thick beams and allow the lane to re-open, Beach said. All play, no work PERU, Ind. (AP) Air Force Col.

Gary Ebert, a wing commander criticized for pressuring wives of senior officers at Grissom Air Force Base to quit their jobs so they would be available for social activities, take. an early, retirement next 1 Clsxsw Kaam TpV-rr B- II ONE LANE CLOSED Trass II (BROOKLYN BOUND) Roadway w. I 1) OPENED BOUND) Truss Cross beams Subway (floor beam Samuel Schwartz. In the process, the original builders failed to galvanize the cable wires, which would have wrapped them in a zinc coating to prevent corrosion. As a result, the northernmost main cable of the bridge is the victim of rust, water damage and pigeon droppings.

A recent survey showed that 190 of the 7,696 wires in the north cable were broken, and hundreds of others were badly pitted. Tests in 1984 with the bridge at first empty and then placed undef a maximum load of 56 subway cars weighing 40 tons apiece showed the cables stretched more than 8 inches under the full load. 1 -Richard Sisk TOM LYNN DAILY MEWS 3d lane shut on bridge Loss of another lane of traffic on the Manhattan Bridge will make today one of the the worst of the year for driving to and from Manhattan. "It promises to be endless gridlock," said a spokesman for the city Department of Transportation. The department also expects that 90,000 more vehicles than the normal 900,000 will try to squeeze into Manhattan on the last weekend of the holiday shopping season, the spokesman said.

About 85,000 cars and 15,000 trucks and. buses use the bridge daily. Many will have to divert to the Williamsburg Bridge or the Brooklyn-Battery Tunnel. The lane closure means three of seven lanes on the Manhattan Bridge are out of service and adds to the ordeal of crossing by car or train that began in August 1985. It was then that the Transit Authority began repairs to four subway tracks crossing the bridge.

That job was completed ahead of schedule three months later. In April 1986 the state Department of Transportation started repairing bridge cables, forcing shutdown of two tracks on the northern side and two lanes of traffic. Officials had been shooting for next April to reopen the tracks and lanes but now think next fall would be abet- TWO LANES (MANHATTAN Concrete-filled steel grd deck LOWER ROADWAY FLOOR BEAM City and state engineers believe the Manhattan Bridge can be saved with extensive repairs, but the case of the Williamsburg Bridge may be terminal A task force set up by the city and state Departments of Transportation will decide by July whether to go ahead with $250 million in repairs to the badly deteriorated main cables of the Williamsburg, or start planning to build a new $1 billion bridge. The main problem with the Williamsburg is that designer Le Herts Buck tried to cut corners to build it faster than the Brooklyn Bridge, and "we are now paying the price," said City First Deputy Trans? portatibn' Commissioner.