Heavy Rain, Erosion Woes Halt Mountain Valley Pipeline

Gilchrist Erects Spans Amid Marshy Terrain

Mon September 06, 2010 - Southeast Edition
Brenda Ruggiero


Crews attaching a pile hammer to a crane.
Crews attaching a pile hammer to a crane.
Crews attaching a pile hammer to a crane. A crane uses a floating mat road for pile driving. Creating access for cranes and materials in a tidal marsh environment was among the project’s challenges. Formwork for the concrete pivot pier. Pouring concrete for the pivot pier.

By Brenda Ruggiero

CEG CORRESPONDENT

Crews are working in Iberia Parish, La., to replace two bridges at Weeks Island. The first, Stumpy Bayou Bridge, is a fixed span, while Bayou Patout Bridge is moveable.

The contract of $16.1 million was awarded to Gilchrist Construction Company by the Louisiana Department of Transportation and Development (DOTD). Work began on June 21, 2010, and completion is expected approximately in March 2012.

The contract calls for replacement of the two bridges along La. Highway 83 in southeast Iberia Parish between Lydia and Weeks Island. According to Bill Fontenot, DOTD district engineer administrator, work was 10 percent complete as of Aug. 19. A total of 7 percent of the time had elapsed for the project.

One of the challenges with the project involved its location.

“The project has required placing embankment and access for cranes/materials in a tidal marsh environment,” Fontenot said. “In addition, the construction period extends through two hurricane seasons. Stumpy Bayou Bridge is going to be built under traffic one lane at a time. Alternating traffic will be controlled with portable traffic signals. The first phase of construction on this bridge will allow for a lane width of only 9 feet, 6 inches for a period of several months.”

The project placement also makes it unique.

“Non-plastic (sand) is being placed on top of geotextile fabric and geogrid in this wet environment to provide stability for the embankment,” Fontenot explained. “A surcharge is being placed, and sand is being capped with two feet of plastic ’clay’ material to guard against erosion from rain and eventually wind/waves from tropical systems. Some hydraulic equipment is being placed on the steel structure rather than on the pivot pier cap in order to guard against damage from future storm surge.”

A total of 16,200 cu. yds. (12,385 cu m) of non-plastic embankment will be used, along with 17,700 sq. yds. (14,799 sq m) of geotextile fabric and geogrid. Precast concrete piles will include 15,976 linear ft. (4,869 m) of 16 in. (40 cm); 2,118 linear ft. (645 m) of 24 in. (60 cm); and 1,104 linear ft. (336 m) of 30 in. (76.2 cm).

Later in the project, 2,300 sq. yds. (1,923 sq m) of limestone will be placed, along with 3,300 tons (2,993 t) of superpave mix and 2,700 cu. yds. (2.064 cu m) of concrete. There also will be 490,998 lbs. (222,712 kg) of deformed reinforcing steel, 561,700 lbs. (254,782 kg) of structural metalwork, 3,230 sq. ft. (2,700 sq m) of steel grid flooring, and 38.09 MFBM (thousand foot board measure) of treated timber.

Major subcontractors include Brudd Construction Co., Marksville, La., for earthwork and embankment; Ernest P. Breaux, New Iberia, La., for electrical; JD’s Rebar & Construction, Alexandria, La., for deformed reinforcing steel bars; Ray-Bar, Baton Rouge, La., for concrete railing, barriers, and approach slabs; LaMay Group, Livonia, La., for seeding; Alpha Services & Products, Frierson, La., for guard rail and object makers; and Pavement Markings Co., Mandeville, La., for pavement markings.

Some main suppliers include Florida Structural Steel, Tampa, Fla., for structural steel fabrication and machinery; Gulf Coast Prestress, Pass Christian, Miss., for PPC piling; Bayou Forest Products, Sulphur, La., for treated timber; and CEG