The new Interstate 64 bridge under construction appears to be balanced precariously over MacCorkle Avenue near Jefferson Road. State highway officials say it is safe to drive under the construction site because the load is properly distributed over the support.
Those are the two things keeping concrete and steel bars from crashing 60 feet down onto MacCorkle Avenue in South Charleston.
Motorists zipping through the area can't ignore the massive bridge construction towering over the road.
A timid passerby might fear the 64-foot-wide, unfinished bridge could collapse on them. After all, it appears nothing is supporting the edge of the project hanging over MacCorkle Avenue.
But there's no reason to hold your breath when driving under the structure, said John Buchanan, project supervisor.
It's a balancing act of mammoth proportions.
According to engineers, the new Interstate 64 bridge connecting South Charleston and Dunbar is being pieced together in a rather unorthodox style.
Workers are pouring concrete in 16-foot sections at a time, meaning one side of the bridge is always slightly off balance. Crews then will move to the other side and pour concrete to balance it out.
That way the structure doesn't tip over, Buchanan said, and the friction of the concrete also helps.
"It's daunting for some to drive under there," said Brent Walker, spokesman for the Division of Highways. "Soon people will just think they're driving under a bridge."
Rebar, or ribbed steel bars inside the concrete, strengthens the structure.
It takes about three hours to pour each segment of concrete, which is pumped through a hose extending from a truck on the ground.
In the end, more than 33,000 yards of concrete will have been used for the new bridge, Buchanan estimates.
Construction began last year and officials are eyeing October 2010 as the finish date.
The 2,975-foot bridge will span the Kanawha River between Dunbar and South Charleston. It will accommodate four lanes of traffic eastbound. The existing four-lane bridge then will be used for westbound traffic only.
SOUTH CHARLESTON -- Balance and friction.
Those are the two things keeping concrete and steel bars from crashing 60 feet down onto MacCorkle Avenue in South Charleston.
Motorists zipping through the area can't ignore the massive bridge construction towering over the road.
A timid passerby might fear the 64-foot-wide, unfinished bridge could collapse on them. After all, it appears nothing is supporting the edge of the project hanging over MacCorkle Avenue.
But there's no reason to hold your breath when driving under the structure, said John Buchanan, project supervisor.
It's a balancing act of mammoth proportions.
According to engineers, the new Interstate 64 bridge connecting South Charleston and Dunbar is being pieced together in a rather unorthodox style.
Workers are pouring concrete in 16-foot sections at a time, meaning one side of the bridge is always slightly off balance. Crews then will move to the other side and pour concrete to balance it out.
That way the structure doesn't tip over, Buchanan said, and the friction of the concrete also helps.
"It's daunting for some to drive under there," said Brent Walker, spokesman for the Division of Highways. "Soon people will just think they're driving under a bridge."
Rebar, or ribbed steel bars inside the concrete, strengthens the structure.
It takes about three hours to pour each segment of concrete, which is pumped through a hose extending from a truck on the ground.
In the end, more than 33,000 yards of concrete will have been used for the new bridge, Buchanan estimates.
Construction began last year and officials are eyeing October 2010 as the finish date.
The 2,975-foot bridge will span the Kanawha River between Dunbar and South Charleston. It will accommodate four lanes of traffic eastbound. The existing four-lane bridge then will be used for westbound traffic only.
The estimated cost of the total project, including design, engineering and utilities, is $196.5 million.
"This is a whole different animal," said Buchanan, who has 32 years of experience with the Division of Highways. "Here, we're building 16 feet of deck at a time."
It's the first time Buchanan has worked on a bridge constructed in this manner. It's also the first time the method has been used by Brayman Construction Corp., of Saxonburg, Pa., which won the contract to build the bridge.
The process is called cantilever construction, and it's a common way to construct pre-stressed concrete spans. Each cantilever is counterbalanced with another cantilever arm projecting in the opposite direction.
Pre-stressed concrete, which is much stronger than regular concrete, will be further strengthened with rebar and steel tendons, Buchanan said.
The new bridge will include eight spans, including a 760-foot main span over the river.
It won't have a support beam under its center or in the river. Piers on each end of the structure will support the new bridge.
Officials say the bridge will include the longest continuous segmental span in the United States.
Crews are working 10-hour days for five and sometimes six days a week. Brayman has about 65 workers on site. Subcontractors also are working on the bridge.
Buchanan said crews are making progress as expected, but the winter months could slow them down.
"January and February might be bad months," he said. "You need to keep concrete at above 50 degrees. When it gets below 20, it's hard for these guys to work."
The state settled on concrete for the new bridge because it is less expensive than steel. The concrete is costing $83 million, or about $30 million less than steel, Buchanan said.
People can monitor progress of the bridge construction online by going to www.wvdot.com, clicking on "Highway Projects" and selecting the proper link.
Three cameras, one at each end of the project and one near the middle of the existing bridge, give updated images every five to 15 minutes.
should have been built years ago. when they started adding the third lanes the whole project was suppose to be done by 2005. I-64 is nothing but bottle neck after bottle neck.
Me Big Coward!(3:55pm 07-24-2008)
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Sorry, but they couldn't pay me enough to drive under that hanging T-bone death trap! Also, I wouldn't even want to be anywhere near that thing during high winds! So you notice it start to see-saw in a big wind, my advice is to get away fast!
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Hillbilly(1:51pm 07-24-2008)
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I was traveling East on 64 thru there yesterday. Sign said 55mph when flashing. The lights were flashing. I was going 60mph. A tractor trailer following behind me about 6ft, at 60mph, thru construction, in a curve, on a bridge, was flashing his lights for me to get over so he could go faster...
WVBridges(12:01am 07-24-2008)
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Stacy...the auxillary lanes between the MacCorkle and Dunbar exits will significantly reduce merging and weaving conflicts between the two exits.
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