New Mississippi River Crossing Safer for Boats and Cars

The new U.S. Highway 82 bridge being built over the Mississippi River near Lake Village trumps its 66-year-old predecessor in size and safety, on land and water.

The $260 million project is still at least two years from being road ready, though it reached a major milestone April 21 with the closure of its main span, a 1,378-foot cable-stayed bridge.

Residents of southeast Arkansas and the Greenville, Miss., area can already see the superstructure’s form.

Two concrete towers climb 425 feet above the river and expel four cable fans directly into the bridge roadbed. The cable-stayed design, the only one of its kind in Arkansas, was chosen for cost and safety.

It will be the third-longest span across the Mississippi and the third-longest cable-stayed bridge in North America.

Connected to the main span are two 591-foot spans that attach to the bridge’s two approaches: the Arkansas side at 3,752 feet and the Mississippi side at 4,602 feet.

Add in new roadway and the total project stretches 20,290 feet, or nearly four miles.

The bridge’s height is awe-inspiring. Below the 425 feet of above-water tower is about another 200 feet of caisson, 120 feet of which was sunk into the riverbed’s hard clay and alluvial soil. At 603 feet from top to bottom, the bridge is taller than any man-made structure in Arkansas or Mississippi that is not a radio or television tower.

Still, it’s the length and the width of the bridge that will change the way cars and trucks pass over it and boats navigate under it. More safely, its designers presume.

HNTB Corp. of Kansas City, Mo., engineered the new bridge’s main span and, coincidentally, also designed the original one.

Likewise, one of the project’s two general contractors, Massman Construction Co. of Kansas City, built the caissons for the first Greenville Bridge. The project is a joint venture between Massman and Traylor Bros. Inc. of Evansville, Ind.

Bridge Versus Boat

Like an aging prizefighter, the Greenville Bridge has sustained enough hits to call it quits — not because its hulking concrete piers cannot stand the abuse but because the barges that keep running into it need a less obvious target.

Since 1972, no bridge on the Mississippi has been struck by barges as many times as Greenville’s, according to technology project manager Jeff Herzer of HNTB.

All those hits have done nothing to make the steel-truss crossing less structurally sound. (Nor did a 1951 collision with an Air Force training jet, which killed the pilot.) But the battle between boat and bridge has simply become an unfair fight.

The new bridge will be no easier to topple, just harder to hit.

It crosses the Mississippi some 2,800 feet downstream from the existing bridge at a part of the river that is not only wider but less curved, which makes the boat-running gauntlet more navigable.

Also, the new bridge’s cable-stayed structure requires fewer piers. While the old bridge has three supports that leave an 840-foot gap for boats to pass through, the new bridge is supported by only two piers and offers a spacious 1,378-foot-wide clearance.

When the new bridge is complete, the old one will be demolished.

The cable-stayed design makes the new bridge not only safer but cheaper, project engineer Gowen Dishman of HNTB said. The bridge’s main span, not including the Arkansas and Mississippi approaches, will cost $111 million, most of which was money earmarked by Congress.

But that figure could have been much larger with a different type of structure.

When the original bridge was built in 1940 to allow something other than ferry boats to cross the Mighty Miss, the project cost $4.4 million, a whopping sum at the time. Building another steel-truss bridge would be economically impossible, Dishman said.

So too would a different kind of cable-supported link, a suspension bridge.

Both structures would have required far more steel and concrete than the cable-stayed version, which will contain more than 11 million pounds of structural steel, some 5.5 million pounds of reinforcing steel and about 109,000 cubic yards of concrete.

Dishman guesstimates a suspension bridge might have required about 20 percent more material and a steel-truss bridge about 30 percent more.

“It was obvious from the beginning it would need to be cable-stayed,” Dishman said.

Massman and Traylor Bros. broke ground on the job in late 2001 but have met several weather-related delays, namely high winds.

Dishman said when gusts top 35 mph it usually becomes too unsafe for crane operation, which curtails progress on the job.

These safety precautions and others, however, have not prevented the project from claiming two lives.

One worker fell into the river and drowned after trying to step from a work platform to a barge. Another was struck by a steel beam.

Still, the newer, safer bridge is expected to save lives, its backers say.

Wider is Better

With its roadway only 24 feet wide, the old Greenville Bridge is a mere capillary for traffic compared to the artery it should be.

The nearest Mississippi crossing to the south is near Tallulah, La., about 60 miles away, and the nearest crossing to the north is 120 miles away at Helena.

In 1994, the Mississippi Department of Transportation issued an engineering report to explore replacing the two-lane bridge with a four-lane connector.

The result is a four-lane passage with 12-foot lanes, a 12-foot outside shoulder and an 8-foot inside shoulder.

Work on the main span should be complete by the end of May, Dishman said. As of mid-March, crews were adjusting the cable stays and assembling the last two fill sections.

What remains is construction of the bridge’s approaches and their connecting roadways.

Last year, a joint venture of Mississippi firm Hill Brothers Construction & Engineering Co. Inc. and Jensen Construction Co. of Des Moines, Iowa, began work on Mississippi’s approach, which includes 2,970 feet of new roadway and 6,406 feet of approach bridge.

Mississippi’s approach work is expected to be finished in April 2008.

In December, the Arkansas Highway & Transportation Department and the Mississippi Department of Transportation agreed to award Texas-based Austin Bridge & Road Inc. a $65 million contract to build Arkansas’ 4,657 feet of approach bridge and 3,225 feet of connecting roadway, a job that is expected to be completed in November 2008.

Though the Mississippi Department of Transportation is the lead agency for the entire project, the two states are splitting the costs. Federal earmarks will pay for all but $15 million of Arkansas’ $55.5 million tab for the main span and side spans.

The remaining $15 million, along with $66 million for Arkansas’ approach bridge and roadway, will be split 80/20 between Arkansas’ federal bridge replacement funds and a state match.

“This is a major portion of our bridge replacement funds, but this is a major project,” highway department spokesman Randy Ort said. “While the majority of our bridge replacement funding over the next two to three years will go to this project, we will still be addressing the state’s most critical bridge needs.”