New and improved
Chattanooga revitalizes Riverfront with new facilities

By Candy McCampbell

Visitors to Chattanooga's Riverfront will soon be able to walk along - and on -the Tennessee River to a new city pier. They'll also be able to watch river traffic from a stepped concrete terrace built on land reclaimed from the river.

The work - which includes a new walkway that will straddle both land and water - is being performed by Continental Construction Co. of Memphis during a $19.9 million project to be completed in May. The contractor will also build a new dock for the Southern Belle riverboat, a new ramp for the Chattanooga Ducks amphibious vehicle, a docking area for boats, a small entertainment amphitheater for children and a passage under Riverfront Parkway that will feature a public art display.

The project is part of Chattanooga's $120 million 21st Century Waterfront, a public-private undertaking that includes a variety of other expansion and renovation projects at the Tennessee Aquarium, the Hunter Museum of American Art and the Creative Discovery Museum.

Continental started its work in November 2003, dividing the Riverfront project into two phases, one at the river and the other beneath nearby Riverfront Parkway where the contractor is building an "art passage."

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At the river, the new walkway will sit on 500, 45-ft.-long, H-shaped steel piles driven into bedrock. The piles are topped with precast concrete slabs and a 6-in. layer of poured concrete.

"The engineers decided the river bank needed sheet piles and rock that come up about 4 ft. above the normal pool," said Continental project manager Kenny Statham. "Above that is landscaping." More than 20 tons of rock had to be trucked in for fill along the river.

A new dock for the Southern Belle riverboat is located about 1,000 ft. downriver from its former base. Burrowing river muskrats had riddled the old city dock's Styrofoam underbelly with holes, and it had to be destroyed, Statham said.

Also demolished was the old city pier, which had steel pipe piles covered in concrete below water.

"We removed the old concrete cells (where the barges tied up) and some old concrete piers underwater," said Gary Owens, president of Tennessee Valley Explosives, of Cleveland, Tenn. Working from a barge, the contractor used a track drill to bore into the caisson and insert plastic pipe in the holes, which were later loaded with explosives.

Some of the old cells were close to the surface, so the contractor supplemented the usual 8.5- by 12-ft. rubber blasting mats with a 12- by 12-ft. wood frame around the cell.

The new 650-ft. city pier, stretching 200 ft. over the river, is being built onto pipe piles as deep as 65 ft. to reach bedrock. The river is about 30 ft. deep in that area, Statham said.

The pier is designed with two surfaces on top.

"The top of the pier will have precast concrete along one side and structural steel beams with bar grating on the other," Statham added. Precast concrete panels about 30 by 5 ft. by 7.5 in. deep are placed side by side and covered with 4.5 in. of poured concrete.

A floating dock at the end of the pier will serve commercial and private boats, and mooring cleats along the river walk can handle private boats. Visiting riverboats can dock at the concrete terrace upstream.

The terraced area is "bumped out" from the original bank, reclaiming about 6 ft. of river, Statham said.

Riverfront Parkway, about 30 ft. above the river's edge, has been open to traffic during construction of the art passage, except for brief halts during blasting, Statham said.

Much of the excavation for the passage had been performed during an earlier contract, but Continental had to finish the excavation and perform the fine grading for the small space using tractors, a mini-excavator, a small crane on the road overhead and "a lot of manual labor," he added. The concrete for the work was pumped into place.

The passage is near the place where Cherokee Indians gathered during their forced removal in the Trail of Tears. It will have permanent Indian art designed by a team of Cherokee artists that celebrates the tribe and its culture.

The passage is lined with walls of 16- by 24-in. masonry cladding.

The number seven is important in Cherokee history and culture, so walls will feature seven 6-ft. pottery medallions, seven steel cutout figures and seven bronze "weeping" panels with water that runs down them, then flows over tiers of steps to a reflecting pool, all in the passageway. Pumps will send the water back up the walls.

The reflecting pool, centered with a stainless steel sculpture of a spider - also part of Cherokee mythology - will be lined with 8- by 16-in., 2.25-in. thick pavers set in mortar, said Will Saxby, project manager for ValleyCrest Landscape Development of Norcross, Ga., the installers of the landscaping, irrigation system and pavers.

Saxby said hexagonal 4-in. pavers are in the walkways and a children's amphitheater built under an arch of the existing Market Street Bridge.

The project also required that the contractor move 80,000 yds. of dirt, mostly from one end of the site to the other, where the terrace extends over the riverbank, Statham said.

Rick Hoosier, general superintendent for East Tennessee Grading of Chattanooga, said moving that much dirt in a relatively narrow site - sandwiched between the river and the parkway - involved "a lot of shuffling and a lot of cooperating" by the contractors.

His crews also formed sharp corners at a 3 to 1 slope in the terraced area using a small tractor followed by "a lot of hand work," Hoosier said. "You get it as close as you can with equipment, but have to finish it by hand."

The sharp corners are a "signature" of Hargreaves Associates of Cambridge, Mass., the international waterfront design firm for the 21st Century project.

"They are renowned for the land forms and sculpted forms they create out of dirt and grass and the surfaces they use," said Dan Kral, project representative for RiverCity Co., the project development firm.

The dirt in the area - formerly industrial land - had to be tested for public use and amended to support more than 500 trees, 3,800 shrubs and 10,000 pieces of groundcover, Saxby said.

The riverbank is also getting 11,000 fascine bundles - live branches of trees that grow by suckering - that will serve as erosion control.

"In the river there will be seven water cannons with 150-hp pumps," Statham said. "The cannons will shoot water 60 ft. to 70 ft. in the air and 100 ft. out."

Because it is part of the Tennessee Valley Authority system, the river remains at a fairly consistent level, varying only a few feet with power generation outflow at Chickamauga Dam upstream, Statham said.