River crossing

Westbound span of Red River bridge replaced in Bossier City, La.

By Angelle Bergeron

Every once in a while, a contractor is lucky enough to bid on the rehabilitation of a project it originally constructed. It’s a welcome reminder, in what is too often a thankless career, of a job well-done, even if the project was delivered more than 50 years ago.

When Austin Bridge & Road LP won the roughly $25 million contract to replace the westbound span of the Red River Bridge on Hwy. 3032 in Bossier City “it was pure coincidence” that the bridge was originally built by the Dallas contractor, said Tony Stehling, the company’s southeast regional manager. 

“The day we bid it, an old employee who is retired got wind of it and called, saying, ‘Hey, that’s the job I built back in 1953.’ He even remembered the job number,” Stehling said.

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The bridge has served well this past half century, supporting more traffic than designers ever anticipated. The average daily traffic was 20,000 in 2004, said Steve Christner, project engineer for the Louisiana Department of Transportation and Development.

“It was in pretty bad shape and it was time to re-do,” he added.

The eastbound bridge was upgraded three or four years ago. However, the westbound span, which was the original, single bridge, had never received the same attention. DOTD designers decided the bridge must be torn down to the river piers and reconstructed from there, Christner said. The bridge is comprised of a combination of concrete girders over land and steel plate girders over the river.

“The bridge we’re putting back has a higher design load, designed for a heavier traffic than it was in the 1950s,” Stehling said. “Those old piers are still strong enough to hold those loads, even with the new design criteria.”

As is the case in most old bridges, the foundations were over-designed because “they didn’t have the engineering technology they have today,” Stehling said. 

The first thing the contractor did after mobilizing was to place delineators on the eastbound bridge and divert two-way traffic to that bridge. Then Austin Bridge & Road set about demolishing and removing the concrete deck from the entire westbound bridge.

“We took the approach piers down 100%,” Stehling said. Rebuilding the approach piers from the foundations, including new pilings, footings, columns, caps and decks, was not unusual. 

“What is unique is there are six main piers where we just modify the top 5 ft. of the piers, doing a little bit of demolition and pouring back a new cap,” Stehling said. 

The approach bents are supported by 12-by-53 H piles with concrete columns and caps and Type 3 concrete girders, said Chris Hughes, project manager. He agreed that the on-land demolition was pretty straightforward.

“Demolishing the top of those six main piers and keeping the environment in a safe condition and debris out of the river is very touchy,” Hughes said. To contain the demolished material, Austin Bridge & Road constructed a platform below the work area that was anchored into the existing concrete piers with support brackets.

“We’re demolishing the top of the piers using a small excavator with a hydraulic ram,” Hughes said. “Once we’re done, we’ll barge it out of there.”

The final, detailed demolition will be performed with jackhammers to get a clean finish and maintain as much integrity as possible, Hughes said.

“The challenge is modifying the top of the six river piers to accommodate not only the widening but, where there were two plate girders, we are going back with four.”

Naturally, the job required the contractor to perform a lot of work from barges.

“It was a pretty good-sized bridge to take down,” Stehling said. He added that the river portion of the job required two 4100 Series II cranes situated on two barges. The contractor requested a no-wake zone, but the primarily pleasure craft marine traffic on the river didn’t pose any real problems.

Once the piers were renovated, the contractor began work on replacing the structural steel, supplied by Afco Steel LLC of Little Rock, Ark.

“Steel was fairly volatile back then, but they gave us a fixed price,” Stehling said.

F. J. Burnell, Inc. of Shreveport holds the largest subcontract on the project, adding on and off ramps to the Bossier City side of the bridge.

“On the Shreveport side, the ramps make a 180-degree turn,” Stehling said. “On the Bossier City side, the bridge just dead-ended into Barksdale Air Force Base.”

F. J. Burnell is performing all of the earthwork, base course, concrete paving and pipe work for the loop ramps.

“The job had about 96,000 cu. yds. of imported borrow that was hauled by Plain Dealing Trucking,” said Buster Netherton, company president. “We used crushed concrete for the base course and about 33,000 sq. yds. of 9-in. concrete pavement.”

By November, Austin Bridge & Road had completed about 95% of the demolition of the bridge, performed most of the substructure work on the approaches and was in the process of forming to pour concrete on the decks.

Currently, the contractor is pouring decking on the approaches. Once the pier widenings are complete, all that remains for Austin Bridge & Road is to set the new structural steel and finish the bridge deck.

The A+B project was bid as a 531 calendar day schedule with a $10,000 per day ($480,000 maximum) incentive, Christner said. It is scheduled for completion in the last quarter of 2007.