The new Interstate 64 bridge is moving across MacCorkle Avenue in South Charleston at the rate of about eight feet a week, causing few delays to commuters using the riverside thoroughfare that passes beneath the new span.

 Portable concrete forms extend from each end of a span segment that straddles a pier adjacent to MacCorkle, and roll along a set of rails mounted atop the pier once a new section of concrete has cured.

"It's kind of like working on a teeter-totter," said William Kelley, district engineer for the state Division of Highways. With the bridge pier serving as a fulcrum, "you pour a little on one side, then pour the same amount on the other. With each pour, one side gets eight feet longer than the other side. After each pour, steel cable is run through the new concrete and stressed."

Use of "traveling" forms eliminates the need for using large static forms and their temporary support structures, which involve extended traffic detours.

"We hope to make a pour every six working days," Kelley said. Traffic on MacCorkle is detoured only when a pour is being made.

Longer sections of concrete will be poured once MacCorkle is spanned on the South Charleston side and W.Va. 25 is crossed on the Dunbar side, and bridge construction moves back across the river.

The decision by bridge designers to go with concrete, rather than steel, as the primary construction component saved the state $20 million, Kelley said. "And that was before steel prices went up," he added.

So far, 20 of 180 sections of the bridge have been poured, and the planned completion date for the bridge is the end of October 2010.

The $93 million bridge will have an overall length of 2,975 feet, and will make use of seven piers - five on land and two at the edge of the Kanawha River.

The main span over the Kanawha River will extend 760 feet.

When complete, the structure will be the longest continuous-span bridge of its kind in the United States.

The new bridge, being built by Brayman Construction of Saxonburg, Pa., will be dedicated to carrying eastbound I-64 traffic across the Kanawha, while westbound vehicles will make use of the existing bridge.

Progress on the bridge's construction can be tracked by viewing images from three webcams now operating at the work site, accessible at www.wvdot.com/projects/I64_Bridge/cams.

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

The new Interstate 64 bridge is moving across MacCorkle Avenue in South Charleston at the rate of about eight feet a week, causing few delays to commuters using the riverside thoroughfare that passes beneath the new span.

 Portable concrete forms extend from each end of a span segment that straddles a pier adjacent to MacCorkle, and roll along a set of rails mounted atop the pier once a new section of concrete has cured.

"It's kind of like working on a teeter-totter," said William Kelley, district engineer for the state Division of Highways. With the bridge pier serving as a fulcrum, "you pour a little on one side, then pour the same amount on the other. With each pour, one side gets eight feet longer than the other side. After each pour, steel cable is run through the new concrete and stressed."

Use of "traveling" forms eliminates the need for using large static forms and their temporary support structures, which involve extended traffic detours.

"We hope to make a pour every six working days," Kelley said. Traffic on MacCorkle is detoured only when a pour is being made.

Longer sections of concrete will be poured once MacCorkle is spanned on the South Charleston side and W.Va. 25 is crossed on the Dunbar side, and bridge construction moves back across the river.

The decision by bridge designers to go with concrete, rather than steel, as the primary construction component saved the state $20 million, Kelley said. "And that was before steel prices went up," he added.

So far, 20 of 180 sections of the bridge have been poured, and the planned completion date for the bridge is the end of October 2010.

The $93 million bridge will have an overall length of 2,975 feet, and will make use of seven piers - five on land and two at the edge of the Kanawha River.

The main span over the Kanawha River will extend 760 feet.

When complete, the structure will be the longest continuous-span bridge of its kind in the United States.

The new bridge, being built by Brayman Construction of Saxonburg, Pa., will be dedicated to carrying eastbound I-64 traffic across the Kanawha, while westbound vehicles will make use of the existing bridge.

Progress on the bridge's construction can be tracked by viewing images from three webcams now operating at the work site, accessible at www.wvdot.com/projects/I64_Bridge/cams.

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