Concrete shapes a city

New administration building wedged into Gretna complex

By Sam Barnes

The cityscape of Gretna, across the Mississippi River from New Orleans, has changed rapidly during the last few years, as city, parish and state officials attempt to put a new face on the government complex there.

The latest addition - a new $16 million, six-floor Jefferson Parish Administration Building - is now rising within a tightly congested area comprised mostly of buildings younger than five years in age. Most notably, a Fifth Circuit Court of Appeals building and a new district attorney's office building border the site.

Brice Building Co. Inc., Metairie, began constructing the six-floor administration building in August 2002 and expects to place nearly 8,000 cu. yds of concrete before its completion in mid 2004. A small section of the building to connect to a district attorney's office building will be built with structural steel.

Sizeler Architects, New Orleans, designed the structure.

According to Frank Milazzo, Brice jobsite superintendent, the post-tensioned concrete building rests on a network of spliced concrete piles that reach 130 ft. in length.

"Before pile driving could begin, we had to remove about 3 ft. of unsuitable soil, then come back with 3 ft. of new fill," Milazzo pointed out. During the excavation, the Brice crew uncovered several footings from an old Ford engine assembly plant that had to be demolished and hauled away.

The stripping operation also encountered weather-related problems, when heavy rains swamped the site during two separate hurricanes last Fall.

"I think in two weeks we got nearly 40 in. of rain," Milazzo said. "When it happened, we just pumped the water and continued on."

More than 200 14-in.-sq. concrete piles were driven in 65-ft. sections and spliced by Kostmayer Construction Inc., Metairie. The company drove an additional 110 12-in.-dia. pipe piles to support the steel portions of the building. The concrete-filled piles reach 130 ft. deep.

Crews then excavated 7 ft. below the piles from the finished elevation and poured piles caps that range from 9 ft. by 9 ft. to 14 ft. by 11 ft.

After Brice poured 5,000 psi concrete for the building's 6-in.-thick first floor slab, a crew with CECO Concrete Construction, Metairie, initiated a large-scale shoring and forming operation for the elevated slab pours.

All of the elevated slabs contain both reinforcing steel and post-tensioning cables tensioned to 33,000 pounds.

Concrete for the elevated slabs contains super plasticizer to accelerate the setting times.

"By accelerating the times, we've been able to achieve 75 percent of strength much faster, which allows the tensioning of the cables to begin earlier (performed by South Steel Erectors Inc., Franklinton)," he said.

CECO is breaking down the shoring three floors below the concrete operation.

"We've got to have three floors of shoring in before we can strip the flooring, so the first floor shoring was removed after the fourth floor was poured," Milazzo said. The crew reached the fourth floor milestone in late March, thus allowing mechanical, electrical, sprinkler and drywall contractors to move into the building to begin work.

To accommodate the heavy downtown Gretna traffic, virtually all of the concrete pours have occurred from 3-9 a.m.

"All of the concrete is being pumped from the ground," he said. One lane of an adjacent one-way street is closed during the pours, then reopened by mid morning once the pours are complete.

According to project manager Pat Descant, the pours are typically performed on Fridays, allowing ample time for the concrete to set and for the erection of shoring and forms to catch up.

"We're then ready by week's end for concrete to be poured for the next section," Descant said.

"We've broken it up into equal stages," Milazzo explained. "On the first floor there were four separate pours, for the second and third we had three pours, and from the fourth to the roof we have two pours."

The floors in the steel section of the building were to be poured in late Spring. "We'll pour that on top of metal decking," Milazzo said.

The floor slabs vary in thickness from a minimum of 4.5 in. to a maximum of 8 in. in areas to support mechanical air handling units. Lafarge is supplying all of the concrete for the project.

"We're currently averaging about 10,000 sq. ft. of concrete placement a week," Milazzo pointed out.

When construction of the building's exterior begins this summer, the Brice crew will erect brick, curtainwalls and windows on the south and west sides of the building, and glass, window walls, brick and precast stone on the east, or main entrance, side. The north side will physically connect to the district attorney's office building.

"The east side is about 50-50 precast and window walls. The precast bands run across the building," Milazzo said. Roof work should begin this month, and will be made of a built-up, two-ply, bitumen system.

Upon completion next year, the administration building will have 80-ft. by 75-ft. council chambers, along with numerous council and parish offices.

"The lobby area will be an open, glassed in area with a semi-spiral staircase and terrazzo flooring," Milazzo said. Mechanical and electrical work is being performed by Towers Mechanical Contractors Inc., Westwego; and Heritage Electrical Co. Inc., Gretna, respectively.

"The steel section of the building will support the building's entranceway off the main road, and will physically connect to the DA's building," he continued.

Access to the district attorney's building will be located at the first floor only.