Almost done

Next-to-last stretch of LA 15 four-laning builds through wetlands

By Sam Barnes

Now that the nearly 7-mi. stretch of LA 15 that begins in Sicily Island and stretches south to Greenville has been raised above the surrounding wetlands, its progress should be unhindered.

Permitting delays created some problems at the project's outset, since work in the wetlands area had to be approved by the U. S. Army Corps of Engineers.

"Nothing could happen until the wetlands permits went through, and that postponed work out there for a few months," said Ken Free, project engineer with the Louisiana Department of Transportation and Development's Chase office.

Free said the $18.8 million project will create a four-laned concrete thoroughfare through Sicily Island and asphalt lanes for 5.4 mi. through a rural area.

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Once finished, only one section of LA 15 will remain to be four-laned to complete the entire corridor, which is funded by the state's Transportation Infrastructure Model for Economic Development.

"We're about 75 percent complete with the embankment in the rural areas and are in the process of pouring concrete in Sicily Island," Free added. "About 60 percent of the subsurface drainage is also complete."

Diamond B Construction Co. LLC of Alexandria is the general contractor and Denton-James Construction LLC of Baton Rouge is performing excavation, embankment construction, subsurface drainage and concrete paving.

Free said a significant amount of excavation is required through Sicily Island, since the new southbound lanes are being built in the path of abandoned train tracks.

"Although the tracks had been removed when the tracks were taken out of service in the 1970s, there was a lot of existing dirt embankment to remove," he added.

Once the embankment was brought "to grade," the crew placed 6 in. of soil cement as a working table followed by 8 in. of limestone and nearly 10 in. of concrete driving surface.

"It's a typical Class A concrete mix supplied by Heck Industries from an on-site portable plant," said Diamond B project manager Ben Elkins. The concrete is not reinforced.

The northbound lanes through Sicily Island will follow the route of the existing two-lane highway.

"There will be about 200 ft. separating the south and northbound lanes when finished," Elkins said. Drainage through the city sections will consist of curbs, gutters and subsurface drain lines.

Construction of the 5.4-mi. rural section began with a massive dirt moving operation to create the new southbound embankment.

"The majority of the fill is coming from off site," Elkins said, "but we also used some of the site excavation. There's a total of about 440,000 cu yds. of embankment and about 258,000 cu. yds. of excavation."

Paving of the rural section will begin this fall with construction of a 6 in. soil cement "working table," followed by 6 in. of asphalt base, 4 in. of asphalt binder and 1.5 in. of wearing course.

"The project was designed prior to the statewide implementation of the Superpave mix design," Free said, "so we're using a Type 8 wearing course produced by Diamond B out of its Vidalia plant 20 miles away." The Superpave system provides greater resistance to permanent deformation, fatigue cracking and low temperature cracking with Hot Mix Asphalt (HMA), and is currently designed into the specifications for all new asphalt roads in Louisiana.

Once the southbound lanes are completed this winter, traffic will be switched over and work will begin on the existing road, which will be used as the northbound lanes when finished.

"We're removing about 60 percent of the road where we need to adjust the grade or where there are foundation problems," Free said. In those areas, 6 to 8 in. of asphalt will be milled and its concrete base demolished and hauled off-site.

The concrete was the original driving surface and had been overlaid several times.

"The contractor will likely haul the concrete away for crushing, and use it as road base on other jobs," Free said.

In locations where the soil is unstable, the contractor will place lime to stabilize the area.

"Shoulders will measure 10 ft. outside the driving lanes and 4 ft. inside, and will be made of 8.5 in. of stone and soil cement topped with 1.5 in. of asphalt," he added. A 57-ft. median separates the north and southbound lanes.

Drainage work requires the installation of reinforced concrete pipe cross drains and open ditches.

Free said that as the four-laning of the LA 15 corridor has progressed from Rayville to Vidalia, traffic flow has increased through Sicily Island. More than $70 million has been allocated for the corridor's four-laning.

"We have been four-laning LA 15 since the early 1980s," Free added, "and the only remaining section runs from just south of Greenville through Clayton."

The Greenville to Clayton project, which includes a new bridge over the Tensas River, is scheduled to begin in 2005 and finish in 2007.

Useful Resources:

For updates on the progress of the LA 15 project, go to: http://www.dotd.state.la.us/construction/chase.html#FRANKLIN