CHARLESTON, S.C. (AP) Within a month, there will be nothing remaining on the Charleston skyline of the two aging steel cantilever bridges that had dominated the cityscape for decades.
The Silas Pearman and John Grace bridges are being demolished now that the eight-lane Arthur Ravenel bridge is open to traffic.
The $632-million Ravenel bridge on U.S. Highway 17 opened in July of 2005 linking Charleston and Mount Pleasant. It is the most expensive bridge ever built in the state and the longest cable-stayed bridge on the continent.
Workers recently used explosives to demolish one of the last large piers from the Grace next to the Cooper River shipping channel.
During recent months, crews have used explosives to bring down sections of the steel superstructures of the two old bridges.
But two sections of the superstructure remain on the Charleston side of the river, too close to neighboring buildings to use explosives. The spans are located between a marina and a State Ports Authority terminal.
During the next few weeks, crews will use torches to cut the steel and lower the trusses. Large beams called shoring towers will be erected next to the remaining spans to support them while crews cut apart the old steel.
Within a month, the steel should be removed and then crews will demolish the piers supporting them.
Some will be demolished with explosives; others will be pulverized using jackhammers, said James Law, a spokesman for the state Department of Transportation.
Once those piers are down, the only remaining work will be to remove concrete debris from the water.
“They have a lot of recovery to do,” Law said. “There is a lot of concrete in the channel and there is a lot of concrete in the creek over by Daniel Island. They have started to do some underwater surveys.”
The contractor, Jay Cashman/Testa, is expected to have all the work done on the $60-million demolition contract next March, Law said.
“They are pretty much on track money-wise and they are on track time-wise, so the project looks good,” Law said.
The Ravenel bridge has a main span of 1,546 ft., 20 ft. longer than the Alex Fraser Bridge in Victoria, British Columbia.