2nd damaged cable found in Skyway
By CURTIS KRUEGER
© St. Petersburg Times,
ST. PETERSBURG -- Inside one of the columns supporting the Sunshine Skyway bridge, engineers have found three broken strands in a steel cable, the second such discovery in recent months.
The Skyway is safe in spite of the damage, state transportation officials stressed. But they said the deterioration shows they must spend more time investigating why portions of certain cables, called tendons, have corroded and broken.
Among the questions they'll try to answer is why five bridge columns apparently were built without anyone filling in small open areas near their bases, said Pepe Garcia, the state Department of Transportation's regional structural and facilities engineer.
Garcia stopped short of saying that work was improperly done on the bridge. But he said he knows of no reason those areas would not have been filled in with grout to keep saltwater or other potentially damaging material out of the hollow concrete columns that hold up the bridge.
The two bridge columns with the damaged cables are among the five that had had no grout in the open areas, Garcia said. The other three do not appear to have damage.
DOT spokeswoman Marion Pscion stressed that the bridge "is perfectly safe." Both she and Garcia said the agency's regular maintenance and inspection routine helped officials discover the damage, and that it would likely take another couple of months to determine what was causing it.
The 4.1-mile bridge, which links Pinellas and Manatee counties across Tampa Bay, rests on 76 hollow columns that contain the steel cables, or tendons. Each tendon consists of 17 steel strands, coated in watertight material. In the recently discovered damage, three of the 17 strands were broken. In the previous case, 11 of the 17 strands were broken.
DOT officials had to lower themselves into the hot, tubelike interiors of the columns to check for damage to the tendons inside.
Garcia termed the damage a "significant deficiency." However, he said additional analysis is required to evaluate how critical the damage is and what repairs are needed. Also, testing will continue to look for more damage.
The Department of Transportation recently finished fixing the hollow column where the 11 strands were broken by filling it with reinforced concrete. That cost about $150,000. One lane of traffic on the bridge was closed at times during the repairs, but it is not known if similar lane closures will be required because of the latest damage.
The possibility that saltwater led to the corrosive damage is one of the theories that will be tested, Garcia said. But no cause has been determined so far.
The open areas of the columns that were not sealed with grout are at the point where the columns rest on concrete footers. The areas are about 3 or 4 inches high and were designed as ports for injecting grout during construction, Garcia said.
Asked if the DOT might hold the bridge builder accountable for improper work, Garcia said it was far too early to make that determination.
The 14-year-old Skyway, built with a relatively new technology for the United States, was designed to last 100 years.
But the latest problems are not the only ones the bridge has had in its relatively short life. Four years ago, consultants who inspected the bridge noted signs the bridge was deteriorating faster than expected.
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