Daily News from New York, New York • 748

DAILY NEWS Sunday, April 12, 1987 Manhattan Bridge, with a southbound lane changed to northbound. "We won't have that option this time, because Manhattan Bridge lanes will be closed," he said. The discovery that rust has eaten away more than 30 of the steel on several anchors of a main cable has knocked back the Manhattan Bridge repair schedule by 18 months. New anchorages, known as eye bars, have to be sunk in the concrete around the old bars. About half of the cable's metal strands will be shifted from corroded bars to new anchors or eye bars that I TTcr-N Bold type denotes I 7f' bridges under repair or 9 7 slated for repair timimSfTYj heights tt I BRIDCE I 'cECJtCE WASHINGTON WASHINGTON jj BRINE lUJMSE SAiXIDEll rA HAMILTON II BRIDCE BRONX I McCOMBS I I J45t ST.

I 1 Willis Ave A I I i 5.V. Bridge 1 1 1 Bridge 8 Triboroughl j3 Bridge queens 1 MANHATTAN QUEENSBORO I BRIPE nil I Oueeif Vtf 1 Lincoln Midtown I Tunnel Tunne XETKLYN NEW 1A jersey JL 1 Holland WlUJAWSBURcV Tunnel BRIDGE AJ- RUNHATTAN 7 I -Tunel (BROOKLYU BRIKE i TRAFFIC FROM PAGE ONE city was sued by automobile and garage interests," he said. "The court ruled that I couldn't close a whole bridge or tunnel to driver-only cars except in emergencies. "But," he added, "there may come a point in the 1990s when we can declare a traffic emergency." On the Williamsburg Bridge, the tricky part of changing the cables comes when the load is to be shifted from an old cable to a new one, said Schwartz. When that happens, all eight vehicle lanes and the subway tracks may very well be shut down for tion's sake, he said, emphasizing that he was not predicting that that would happen.

Main cables have never been changed on any suspension bridge, he said. Four old cables are to be replaced with two new ones of superior strength. City and state engineers are still working out a way to do it, and engineers from all over the world are watching with keen interest, he said. Through 1997 But probably not with as much interest as drivers, who make more than 108,000 trips across the Williamsburg Bridge on weekdays, or the 85,000 subway riders who do the same. Schwartz said that Brooklyn commuters will suffer the most until the end of the decade: Both the Manhattan and Williamsburg Bridge reconstructions are expected to run to 1997.

"Normal" street congestion is already eliminating such handy options as detouring through other streets, Schwartz said. In 1979, when the Williamsburg Bridge's outer roadways were under repair, traffic was rerouted along Delancey St. to the rSfc SL BRIDGE WORKER uses torch on Manhattan Bridge with Empire btate building in c-acKground mJvs CAXMINE DONOF1HO DAU.Y mnmmmn Bridge men were Total estimated cost $226 million By CUS DALLAS i.i.i.i jahr said. "They used asfies and sand in the old days." It didn't corrode steel, but it blocked drains and sewers. Today, we have epoxy, to coat reinforcing steel." "We're using epoxy paint on bridges to retard the; saltwater soaking," Zandalasini said, and added wistfully, "But we'll never get watertight expansion joints." (Rubberized compounds fill gaps between the roadway joints and expand or shrink with temperature changes).

"The East River bridges were the only ones the feds would go with on epoxy," Langjahr remarked. Years of benign neglect! (read: no money!) and Scotch- tape-and-twine repairs left! the city's bridges seriously' deteriorated after the city's referring to a still-existing Roman road built around 300 B.C. The three sat around a chart-littered conference table with George Zandalasini, the deputy director for engineering management of the department "If anything, they overbuilt for safety," Zandalasini observed. "Steel is better today, because of alloys. We also have high-strength bolts of excellent quality.

We don't use rivets any more. You never knew whether a rivet was tight in the hole. We can test bolts to see if they're in tight" "The builders didn't foresee how much salt water from salt spreading would leach through porous concrete and corrode buried steel," Lang- Upper roadways being rebuilt Completion: late 1989 Daily News Staff Writer Bridge builders who spanned the East River at the turn of the century built well with the materials they had, never able to imagine the incredible mass and weight of traffic that would wreak havoc with their proud bridges in the future, according to Ernest Langjahr, the chief engineer for bridge design in the city's Department of Transportation. "The concrete they used was as good or better, compared to today's concrete," he said. "It's quality control look at the Appian Way," added John McTigUeif, thfcvTranspor-tation Department's' assistant commissioner of engineering, Lower roadways to be rebuilt Start late 1989 Completion: 1993 '-'Source: New York State Dept.

of Transportation THOMAS LYNN DAILY NEWS.