Walker says the transportation department picked the concrete box girder system because a bridge made of steel would have cost $30 million more.
The structure is the first bridge in West Virginia to use the system with pre-stressed concrete. The pre-stressed concrete, much stronger than regular concrete, is further strengthened with rebar and steel tendons.
It's also unlike other bridges because it doesn't have a support beam in the river, under its center. Instead, it uses a balanced cantilever system. Each cantilever, a beam supported on only one side, is counterbalanced with another cantilever arm projecting in the opposite direction.
Every bridge in West Virginia is inspected every two years. Project engineer Ahmed Mongi said the tunnel inside the bridge will allow inspectors to check for cracks and other structural problems.
He said the area also would allow crews to add more support to the bridge in the future.
Work on the bridge started in June 2007, with span construction starting a year later. Workers completed the main 760-foot span last year.
Mongi said construction has gone well on the bridge, especially considering crews started on opposite sides of the Kanawha River. He said some bridge projects have wound up several feet out of alignment when the structures finally met in the middle, but the new I-64 bridge was only a couple inches off.
"We were very fortunate," he said.
Buchanan says crews will begin work on the old bridge this fall once the new eastbound bridge is open.
He said two lanes will stay open at all times, but crews will work to repair the old structure's surface. Work on the old bridge should be complete by December of next year, he said.
Highway officials say the current bridge carries an average of 78,000 vehicles a day and 15 percent are trucks.
Contact writer Zack Harold at 304-348-7939 or zack.har...@dailymail.com.