Using soil-anchoring technology to stop soil sliding near the Mississippi bank was discussed Wednesday by commissioners who manage the U.S. 80 River Bridge for Warren County.

Construction of two, 10-foot retaining walls in different positions on the sliding bluff directly below the old U.S. 80 bridge has gained favor, but two natural gas transmission lines crossing the river are an impediment.

Preliminaries discussed last week in talks between the board and engineers, geotechnical and soil stabilization specialists involved nailing two, 10-foot concrete retaining walls 50 to 60 feet into the earth. Cost estimates by ABMB Engineers peg design and construction at $622,360.

“It’s structurally deeper than anything you’d get with a cross tie or sheet metal,” said Tom Hill, a commission member and retired Army engineer.

But expected wrangling with Gulf South Pipeline over who will move and pay for relocating the 14-inch lines running through the location of the lower wall could inflate the project’s cost and the time it will take. “I’ll resign before we move the lines,” Hill said, projecting it might take years.

The creeping slope’s effect on towers and shorter piers, or bents, beneath the bridge is the subject of a $2.5 million stabilization effort that began last summer. Commissioners want the lines moved to ensure the safety of that and any other multimillion-dollar work involving the bridge’s larger supports.

“That stuff is going to break one day,” commisisoner Ray Wade said, adding costs are sure to inflate due to the presence of the gas lines. “What you see won’t be what you get.”

Commissioners had asked pipeline officials in 2006 about the availability of automatic shutoff valves when applying for security cameras now in various locations on the span.

“We hadn’t gotten anywhere with them on that,” chairman Robert Moss said.

Work to replace bearings and concrete and reposition a wind-shear device atop pier 2, the first large pier from the Mississippi bank, garnered just one offer Wednesday. Vicksburg-based Riverside Construction bid $997,600 to address the work, geared to stop further shifting in the pier.

The bridge’s hired architectural services firm, Baton Rouge-based HNTB, had estimated the pier work cost at about $593,000. Commissioners delayed approving the bid until legal counsel and HNTB can review it.

Riverside was the lone bidder on another ongoing project with cost overruns, the $3.4 million project to replace the T-dock crane support structure at the Port of Vicksburg.

“Insurance runs the price up,” said company co-operator Don Miller, present for the bid opening. Liability protection for working near railroad right-of-way is expensive, commissioners said.

In the bridge’s annual stability report for 2007, no westerly movement was detected after a decade of steady movement that totaled more than 9 inches.

After World War II, Warren County bought the bridge from the private company that built it and opened it in 1930. Since then, the county has appointed a commission to operate the river crossing, now only used by trains and utility lines, on a break-even basis.

On the agenda

Also Wednesday, bridge commissioners:

Received a report that rail traffic for January at 23,045 cars, was slightly off the pace of 2007, which averaged about 25,000. Kansas City Southern only reports the number of cars and not any trends associated with it, but commissioners said it was the slowing national economy that may have played a part.

Received payment from KCS of $95,148 reflecting November’s car counts. It reflected a per-car rate of $4, up from a $3.75 rate the railroad had paid for the past several months.

Named officers and appointees for 2008. The chairmanship of Robert Moss was renewed, while the panel unanimously chose O.A. Williams as vice-chairman. The Halford Firm and ABMB were kept as auditor and engineering firm, respectively. HNTB will continue handling the structure’s annual inspections and review stabilization projects.