WORK STALLS ON NEW MISSISSIPPI RIVER BRIDGE

Work on the Bill Emerson Memorial Bridge across the Mississippi River at Cape Girardeau, although halted for months, is back on track and construction work should resume in May, officials from Missouri's Department of Transportation said.

Earlier this month, officials with the state agency and representatives of HNTB, the company which designed the new bridge, were in Cape Girardeau to answer questions about the status and progress of the bridge.

The new bridge project began in 1992, when HNTB was selected as the consultant for the final bridge design. In July 1996, the actual construction of the 4,000-foot-long cable-stay bridge began. But construction halted in 1997 after fissures were discovered in the limestone beneath the river.

Steve Hague, HNTB project manager, said the fissures wouldn't have posed a problem for normal traffic on the bridge or if the bridge was being built elsewhere in the state. However, the bridge at Cape Girardeau is being built to withstand an earthquake of the magnitude of the 1812 quake at New Madrid.

The problem with the rock fissures has set the construction project back about a year. But Scott Meyer, district engineer for MoDOT, said work will resume soon.

In March a contract is to be let for the jet grouting, and in May the jet grouting work should begin along with work on the Illinois approach span. The bridge is anticipated for completion in 2002.

Rumors about the status of the Cape Girardeau Mississippi River bridge, its design and safety have been flying since the construction contract with Flatiron Structures Co., LLC, was dissolved in December. When the bridge was being designed, two core samples were drilled to determine what type of rock structure lay beneath the river. Both samples showed solid limestone.

However, when Flatiron dug a hole to begin construction of pier 3 in the middle of the river it discovered fissures in the rock filled with mud and clay. Work stopped and the design company came back and did another 23 borings to map out what was under the river at pier 3. Additional borings also were done at the other piers headed into Illinois. No evidence of fissures have been found at any other pier location.

Using the new information, the transportation department and design firm have come up with a solution called jet grouting.

Hague explained that the process is similar to a dentist filling a cavity in a tooth: Water and air will be used to wash clay and dirt from the rock fissures, and then concrete grout will be injected into the fissures to strengthen the rock.

After the fissures are filled, the rest of the bridge design will continue as planned.

HNTB was founded in 1914, and has designed more than 5,000 bridges around the world. The company designed the existing Cape Girardeau bridge in 1927.

BRIDGE FAST FACTS

Location: The new bridge connecting Cape Girardeau and East Cape Girardeau, Ill., will be approximately three blocks south of the existing structure in Missouri. In Illinois, it will be very near the existing bridge site.

Design: The structure will be supported by a total of 15 piers including the land abutments in Missouri and Illinois.

Main span: The first four piers from the Missouri side support most of the structure. This 1,050-foot-long main span area crosses the navigational channel of the river. This portion also will include suspension cables for added strength. A bridge of this type is known as a cable-stay structure.

Illinois approach: Piers 5 through 15 make up the Illinois approach span. They are positioned from where the cable-stay section ends and connects with the Illinois shore. These piers are much closer together than those that comprise the cable-stay section.

Width: At approximately 100 feet wide, the new bridge will be nearly five times as wide as the current structure. Four lanes, two going east and two going west, along with roadway shoulders will be included.

Length: The new structure will be nearly 4,000 feet long. This is similar to the length of 13 football fields.

Height: It will be 60 feet above the river.

Lighting: Included are 140 lights to welcome motorists to the region. The Clark Bridge in Alton, Ill., has similar decorative lighting.