BRIDGING THE MISSISSIPPI RIVER: WORK ON EMERSON SPAN IS PROGRESSING

Missouri Department of Transportation engineer Stan Johnson knows there is work being done on the Bill Emerson Memorial Bridge. The public just can't see it.

This year, most of the work will be beneath the Mississippi River as construction crews set the foundation for the pier in the middle of the river.

"People will not be able to see a whole lot of progress, but it will be there," he said.

Traylor Brothers Inc. of Evansville, Ind., is preparing to proceed with pier work for the main span of the new bridge. The Missouri Highway and Transportation Commission awarded the $53.7 million contract in March.

Johnson said the contractor is making changes to the coffer dam in the middle of the river, building up the "sand island."

Larry Owens, project manager for Traylor Brothers, said construction work began in June.

The caisson or pier foundation will be sunk into the bedrock beneath the river bottom. When finished the foundation will be about 75 feet below the surface of the river, Johnson said. When the foundation work is completed, it will be 67 feet wide, 109 feet long and about 34 feet tall.

Owens said a giant steel "cutting shoe" on the caisson will cut through the river-bottom soil to reach bedrock.

Sinking the caisson will take the rest of this year and extend into late winter or early spring, Owens said. It will be at least a year before the public will see any pier work above the river, he said.

Work on the unfinished concrete pier along the Missouri shore will resume this fall and should be completed by next summer.

Currently, the contractor has 25 to 30 people working on the bridge. As many as 70 or 80 are expected to be working at the height of construction later this year, Owens said.

In all, the contractor will build three piers and install support cables. Construction crews also will build the main-span bridge deck and roadway and install decorative lighting.

Johnson said the decorative lighting will have a special switch that towboats can trigger with a search light to turn off the bridge lights so they don't interfere with visibility for barge traffic. The lights would come back on after barge traffic passes beyond the bridge.

Johnson said the Coast Guard dictated the lighting control.

On the Illinois side the piers and steel girder work for the approach span has been completed by Massman Construction.

Two additional contracts are needed to complete the new bridge. They are construction of a concrete driving surface on the Illinois approach and extension of New Highway 74 (Shawnee Parkway) from Sprigg Street to the bridge.

Johnson said all of the bridge work could be completed by 2003.