I-20 bridge study shows ‘significant movement’|[9/14/06]

Published 12:00 am Thursday, September 14, 2006

A long-awaited structural study shows &#8220significant movement” in the Interstate 20 bridge across the Mississippi River.

Members of the Vicksburg Bridge Commission, who manage the Warren County-owned U.S. 80 bridge across the river, discussed the study for the first time Wednesday.

The report was released in May by engineering consultants Modjeski & Masters and directed by the Louisiana Department of Transportation and Development, which manages the four-lane river crossing that opened in 1972.

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Superintendent Herman Smith of the &#8220old bridge” said LDOTD sent copies of the report, in the making for more than two years, to the commission office earlier this month.

It does not indicate any danger to travelers, but most revealing in its findings is &#8220significant movement” in the E2 pier of the 34-year-old structure. Two inclinometers, devices used to measure movement of objects with respect to gravity, buried near the pier have been damaged beyond use. The report characterized the erosion of the earth around the bridge’s piers as &#8220deep-seated rotational movement.”

The report suggested its findings should not be used in connection with any other structure, but commissioners on the board that manages the neighboring U.S. 80 bridge have said since the study’s outset that it would have a direct impact on future efforts to shore up the piers holding up the older span.

&#8220It’s too close not to have an effect on us,” commission chairman Robert Moss said.

Built in 1930 and purchased by Warren County in 1947, the old U.S. 80 bridge has shifted to the west over the past 76 years. Most of that movement has been seen at Pier 2, the second concrete pier from the Mississippi bank, directly across from the E2 pier on Interstate 20, but movement has been recorded at other places.

The total price tag on stabilizing the entire structure was $50 million over a 15-year time span. Studies by private firms and the U.S. Army Corps of Engineers have estimated the cost of just shoring up the pier beneath the older bridge at $2 million or more.

Later, Jimmy G. Gouras, lead grant writer in the commission’s efforts to get federal funding for a pedestrian park and bicycle path on the U.S. 80 bridge’s former roadbed, told commissioners that state funding could be obtained to stabilize the bank on the Mississippi side of the bridge.

Estmates have been in the $10 million range for any kind of slope stabilization project. Gouras said it wasn’t likely any one source alone, federal or state, would fund that entire bill, but the commission &#8220has a reasonable chance” to obtain soon-to-be-available community development block grants from Mississippi Development Authority. The board was agreeable to the notion.

MDA will be the administering agency for $300 million in disaster grants from the federal government to localities, a portion of which will be available for economic development.

As for the bridge park, it was dealt a serious blow when Kansas City Southern Railway came out decidedly against the efforts, citing safety and liability concerns.

The railroad has promised litigation on the park idea if ever realized. Litigation has also loomed with the lease the railroad pays per car to cross the bridge.

The rail traffic for August was reported to the commission at 27,825 cars, down since July but still at a steadily higher clip since the 320 miles of rail the company runs between Shreveport and Meridian became part of a joint venture between they and Norfolk Southern Corporation.

In other business, the commission: