Watch an audio slideshow about the bridge project at:

http://media.cnpapers.com/bridgingthegap  

SOUTH CHARLESTON, W.Va. -- Bridge-building history was made Wednesday, when the final concrete pour was made to complete the mid-river main span of the Dunbar-South Charleston Interstate 64 bridge over the Kanawha River.

"Today, we're celebrating the achievement of closing this span and entering it in the record books," said West Virginia Secretary of Transportation Paul Mattox, in a ceremony atop the bridge at mid-river.

The 760-foot-long main span is the longest concrete box girder span in North America. When the bridge crosses MacCorkle Avenue in South Charleston and W.Va. 25 in Dunbar and connects to approach and exit ramps on both shores, it will be the longest bridge of its type on the continent. It is expected to open to traffic in the fall of 2010.

The new span will be devoted to eastbound traffic only, carrying three through lanes and one auxiliary lane across the Kanawha. The auxiliary lane is designed for use by vehicles traveling between Dunbar and South Charleston, giving them the chance to cross the bridge without having to merge into the through lanes. The existing I-64 bridge will be dedicated to three through lanes and one auxiliary lane of westbound traffic.

An average of 78,000 vehicles, many of them driven by workday commuters, use the I-64 bridge each day, according to the state Division of Highways.

Work crews on the span are using a unique balanced cantilever system of construction, in which traveling cement forms are extended in 16-foot increments from each side of the bridge's shore-mounted piers. Thousands of I-64 commuters have been closely following the bridge's section-by-section march across the river. Those monitoring a webcam on the Web site of Brayman Construction, the Pennsylvania-based contractor building the span, also can track construction progress.

"No piers are in the water, so there are no obstructions to river traffic," said Mattox. "That makes the Coast Guard happy."

Watch an audio slideshow about the bridge project at:

http://media.cnpapers.com/bridgingthegap  

SOUTH CHARLESTON, W.Va. -- Bridge-building history was made Wednesday, when the final concrete pour was made to complete the mid-river main span of the Dunbar-South Charleston Interstate 64 bridge over the Kanawha River.

"Today, we're celebrating the achievement of closing this span and entering it in the record books," said West Virginia Secretary of Transportation Paul Mattox, in a ceremony atop the bridge at mid-river.

The 760-foot-long main span is the longest concrete box girder span in North America. When the bridge crosses MacCorkle Avenue in South Charleston and W.Va. 25 in Dunbar and connects to approach and exit ramps on both shores, it will be the longest bridge of its type on the continent. It is expected to open to traffic in the fall of 2010.

The new span will be devoted to eastbound traffic only, carrying three through lanes and one auxiliary lane across the Kanawha. The auxiliary lane is designed for use by vehicles traveling between Dunbar and South Charleston, giving them the chance to cross the bridge without having to merge into the through lanes. The existing I-64 bridge will be dedicated to three through lanes and one auxiliary lane of westbound traffic.

An average of 78,000 vehicles, many of them driven by workday commuters, use the I-64 bridge each day, according to the state Division of Highways.

Work crews on the span are using a unique balanced cantilever system of construction, in which traveling cement forms are extended in 16-foot increments from each side of the bridge's shore-mounted piers. Thousands of I-64 commuters have been closely following the bridge's section-by-section march across the river. Those monitoring a webcam on the Web site of Brayman Construction, the Pennsylvania-based contractor building the span, also can track construction progress.

"No piers are in the water, so there are no obstructions to river traffic," said Mattox. "That makes the Coast Guard happy."

Using concrete box girders rather than steel also saved the state $25 million in construction costs, said Steve Muck, Brayman Construction's president and CEO. "And it will have a longer service life and require less maintenance," Muck added. "This is a great example of innovation."

While the final pour on the main pier was made at about 8 a.m. Wednesday, a small, ceremonial foot-deep square was left unfilled for the afternoon ceremony. Mattox, Muck and Tom Smith, state coordinator for the Federal Highway Administration shoveled the final gallons of concrete into the void from wheelbarrow, and a worker finished the ceremonial pour with a trowel.

Smith said the $196.5 million Dunbar-South Charleston I-64 Bridge is the second largest federal aid project ever undertaken in West Virginia. The recently completed Blennerhassett Island Bridge carrying U.S. 50 over the Ohio River at Parkersburg is the largest. The two projects, which involve a half-billion dollars in federal spending, represent "a long-term investment in America's economy."

The bridge is the first balanced cantilever span ever built by Brayman. Its record-setting scale "pushed the limits of engineering to provide a clear channel to river navigation," Muck said. "Its geometry is very challenging, with its curves and slopes. We were shooting grades and elevations every day at the same time of day, because the bridge moves a little bit daily, due to changes in temperature. It can raise or lower as much as six inches until the spans are connected."

A total of eight spans are being used to carry the bridge's 2,950-foot length across the river and shoreline roadways.

One of the biggest problems facing bridge designer Santiago Rodriguez, who was on hand for the ceremony, was designing a span "with no expansion joints for almost 3,000 feet."

The bridge itself carries a price tag of $93.6 million, with about $60 million of that amount spent as of June 1. An additional $103 million has been spent on utilities, right of way and engineering.

During its peak construction period, a work force of about 120 individuals toils on the bridge.

"They're on the job working by 7 a.m., even if it's 20 degrees out," said Chris Cortez, Brayman's project manager. "They're a tough bunch of guys. All the union ironworkers and crafts people here in the Charleston area performed wonderfully. For an out-of-state contractor to come in and find such great, skilled workers is wonderful."

Reach Rick Steelhammer at rsteelham...@wvgazette.com or 304-348-5169.