Growing an interstate
Contractor appeases locals while expanding Sulphur interchange

By Sam Barnes

Just how a heavily used interchange in Sulphur would remain open was uncertain when its $19.6 million expansion began in July 2003.

A proposal calling for the temporary shutdown of the LA 27 interchange was unacceptable to local businesses, so Gilbert Southern Construction of Ft. Worth, Texas, used "constructability" to find a solution.

The Gilbert Southern project team chose to build temporary on and off ramps to appease the locals.

"By doing that, the ramps could remain open during the project," said project manager Dan DeKaye said. "We're in the middle of building the final ramps now." The final ramps have been edged outward because of the roadway's wider swath.

Temporary east- and westbound driving lanes were also built along the entire 1.5-mi. jobsite so four lanes of traffic could be maintained.

advertisement

"We built detours along the outside lanes, then kicked traffic out to begin constructing the center of the new interchange bridge and to demolish the roadway leading to the interchange," DeKaye said.

Ultimately, the project in Calcasieu Parish will expand I-10 at the LA 27 interchange from four to six lanes and merge two bridges into one. The project requires the complete removal of the existing bridge followed by the construction of a more functional five-ramp concrete interchange.

Construction of the bridge began with a significant foundation phase performed during the wettest spring and summer on record for southwest Louisiana.

"The abutments and columns are built on caissons that are about 65 ft. long and 6 to 8 ft. diameter," DeKaye said. W. W. Foundation Drilling Ltd. of Houston is performing the foundation work.

Concrete columns, girders and a poured-in-place deck will follow the caissons, with girders supplied by Gulf Coast Prestress of Pass Christian, Miss., and ready-mix concrete supplied by Dunham Price of Westlake. The longest bridge span reaches 140 ft.

After the inside bridge lanes were finished, traffic was moved onto the new lanes so that the existing east and westbound bridge spans could be demolished and reconstructed.

Heavy steel beams were removed and the bridges were "taken down to their foundations," said project manager Pat Cline.

"Switching from steel to concrete beams has made the bridge about 3 to 4 ft. taller, simply because concrete beams are taller than steel," Cline added. Other interchange work requires construction of three block retaining walls along the bridge and ramp embankments.

A new six-lane interstate both east and west of the bridge is also being constructed and was preceded by a significant earthmoving phase to create new road embankment.

"About 120,000 cu. yds. of embankment was placed, some of which to accommodate the higher grade of the new bridge," DeKaye said.

In one location, a drop in road elevation was required to provide clearance beneath an existing overhead pedestrian bridge in close proximity to the interchange.

"The east side of the job has an arched pedestrian bridge, and there's a 3- to 5-ft. cut to go beneath it," DeKaye added.

As of July, the Gilbert Southern crew was about 70 percent complete with the earthmoving.

After the embankment is in place, the Gilbert Southern crew will rebuild the road with a cement-treated subgrade, 8 in. of crushed concrete and limestone, and 12 in. of concrete paving for the driving surface. About 31,000 tons of concrete is being demolished from the existing roadway and re-used in the new road base, and 50,000 cu. yds. of concrete is being placed for the driving surface.

DeKaye said the expansion project should be finished by the end of the year.

"We're currently on track to finish by the end of December," he added. About 70 to 80 crewmen are working at the site.

A soon-to-be-awarded project to the west will further the six-laning of I-10 from LA 27 to Coone Gully. The project was originally bid in June, but the lowest bid of $49.2 million by Gilbert Southern was higher than the Department of Transportation and Development's original estimate.

The project, to re-bid this month, will require grading, subgrade treatment, lime treatment, in-place stabilized base course, asphalt milling and a Superpave asphalt driving surface. Construction should begin by late fall.

Useful Source:

For an update on the progress of the LA 27 project, go to: http://www.dotd.state.la.us/construction/charles.html#CALCASIEU