A 480-ton section of the old Sunshine Skyway will be removed Tuesday in a complicated demolition procedure expected to take four to six hours. Weather permitting, the first demolition of the bridge's main span will begin at 8 a.m.
Watching it won't be much of a spectator sport.
As a safety precaution, the Coast Guard has established a safety zone 2,500 yards in Tampa Bay around the main span, said Joe Blasewitz, the state Department of Transportation project engineer. No vessels will be allowed in that zone.
In addition, the old Skyway bridge will be closed to fishing Tuesday. No one will be allowed on the bridge during the demolition. Traffic will not be permitted to stop on the new Sunshine Skyway to watch the work.
"People will be better off watching it on the 6 o'clock news," Blasewitz said.
The Hardaway Co., the demolition project contractor, has 48 hours to complete the work. The Tampa Bay shipping channel will be closed until the demolition is completed, but not longer than 48 hours, Blasewitz said.
If strong winds or bad weather develop Tuesday, the work will be postponed until Wednesday. The demolition will not be done at night.
"It's pretty complicated work, but we've looked at every possible contingency," Blasewitz said.
The old bridge, replaced by the new $240-million Skyway in 1987, must be demolished because it limits shipping in Tampa Bay. Most of the main section of the old southbound Skyway span collapsed when it was hit by a ship in 1980, killing 35 people.
But the entire main span on the old northbound Skyway remains. It is 800 feet wide, with a vertical clearance of 150 feet. The new Skyway main span is 1,200 feet wide and 175 feet high.
The first step in Tuesday's demolition is cutting free a 360-foot section in the middle of the steel main span. Engineers considered cutting bolts 8 inches in diameter that link the section to the rest of the main span, but it will be easier to use torches to cut connecting vertical beams, Blasewitz said.
Once the 360-foot piece is free, huge hydraulic winches mounted on the bridge and a system of blocks and cables will be used to slowly lower the loose section.
If all goes as scheduled, lowering of the section will begin at 10 or 11 a.m., Blasewitz said.
The section will be lowered 150 feet to two barges under the main span. That is expected to take four to six hours.
"It will weigh 480 tons, and one barge could handle it, but we'll use two," Blasewitz said. "The barges will take the section to the south side of the bridge, where it will be cut up."
A 220-foot section of the bridge will remain jutting out on each main pier. These pieces will be dismantled for removal.
The most precarious part of the $8.1-million demolition project will be razing the massive main piers.
Explosives will be used for the work, scheduled for later this year.
Altogether, the demolition includes removing 9,450 feet of bridge, 64 piers and tons of underwater pier foundations.
Some bridge rubble will be used in artificial reefs next to the Skyway fishing piers and on reefs in the Gulf of Mexico.