On construction sites, challenges come in all shapes and sizes.

Take the Liberty Street Parking Garage, now under construction in the historic district of Savannah, Ga. Among the issues facing the construction team were constructing a facility that would blend with the historical setting, building on a site that's totally surrounded by development, and building without disturbing neighboring residents and businesses or the throngs of tourists that visit Savannah each year.

And then there was the matter of maintaining tower crane security during the recent G8 conference on the Georgia coast.

It's a tall order. But the project team, led by general contractor Archer-Western and construction manager Boyken International, is proving up to the task.

Parking has long been an issue in Savannah's historic district, particularly as tourism has grown, and several years ago the city began developing plans for a new in-town parking deck to be constructed near its Civic Center and Visitor Center. Tourists and others using the deck would have easy access to the city's trolley system, which would transport them throughout the area and then, at day's end, return them to the parking facility and their cars.

To bring the project to fruition, the city called on Poticny, Deering, Felder Architects to develop a design. What ultimately emerged was a six-level facility with 54,000 square feet per level and a total of 890 parking spaces. The project, to be built on a site of approximately 1.25 acres, had a pricetag of about $9.5 million.

Atlanta, Ga.-based Boyken International was brought on to consult with the city during the bidding process and to provide on-site project management during construction. Dan Smirl is Boyken's senior project manager on-site, and Simon Ormsby is assistant site manager.

Archer-Western was named as the contractor to handle construction. David Powers is serving as Archer-Western's superintendent on the project, with Derrick Buchannon as assistant superintendent and masonry superintendent. Napolean Hightower is project engineer, and Steve Thomas is assistant project engineer. Lance Pepin is senior project manager.

Work on the project began late in 2003 with installation of some 272 augercast piles. These piles, most of which were 18 inches in diameter, were sunk to depths of about 70 feet.

"The decision to use augercast versus driven piles was made early on," notes Barry Stein, Boyken's director of program management, "to minimize problems with vibration potentially affecting adjacent structures."

Dynamic Concrete Pumping, Jacksonville, Fla., handled placement of the augercast piles. The concrete came from Conex Concrete.

The site had previously been a paved surface parking lot, and during much of the pile placement operation the pavement was left in place.

"We drilled the piles right through the surface of the parking lot," notes Boyken's senior project manager Dan Smirl, adding that this approach went a long way toward maintaining a clean site during the early sitework phase. "We only ripped up the old pavement when we were ready to construct the pile caps, grade beams and slab on grade."

As pile placement moved ahead, crews began construction of the approximately 70 pile caps called for in the design — still removing the old asphalt only as needed.

"In some areas, the soil was stable enough that the contractor could simply cut through the surface asphalt and earth-form the grade beams," notes Simon Mortimer, Boyken's vice president of Atlanta operations.

Generally speaking, groundwater was not a problem. In fact, the only time that water was a problem was during excavation of the elevator pit.

As the at-grade work moved ahead, attention turned to construction of columns and exterior walls. The cast-in-place walls provide important strength and durability while also providing a very good substrate for the parking deck's brick façade — an important design element, and one that was essential to allow the deck to blend in with the look and feel of other structures in the historic district.

In fact, the designers took the façade one step further. Rather than simply applying a brick exterior, the design is such that the exterior walls of the deck resemble a line of row houses. Open louvers and window openings will add to the effect while also addressing issues of lighting and ventilation.

"The key in the overall design is to add to the historic district and not detract from it," notes Stein, adding that the designers have done a good job. "In fact, I tell the city we will have to put up good signs identifying the structure as a parking facility," Stein adds, "or they might have people driving right by it as they look for a more traditionally plain parking garage."

Because of the complex openings, numerous individual pours have been required during wall construction. This has also required careful attention to pour scheduling. Smaller pours are completed using a concrete bucket, while larger pours are pumped.

The brick work, which is being self-performed by Archer-Western's masonry crews, follows wall construction. The project calls for the use of tinted mortar to further enhance the visual appeal of the structure. The masonry component is on the critical path, so masonry work begins close behind completion of each portion of the cast-in-place walls. Portions of the walls also incorporate ornamental metals including shutters, grills, railings, and louvers, further complicating this aspect of construction.

Meanwhile, as the walls and columns go up, other crews begin forming the post-tensioned elevated slabs. This involves the use of 3/4-inch Plyform deck forming for the horizontal slabs as well as metal pan forms for the cast-in-place beams. Engineered prefabricated wood joists are used to support the deck forms, notes Archer-Western's Powers, with post shores supporting the joists. Columns are on 21-foot centers, so the individual joist trusses have a length of about 20 feet apiece.

"The wood joists have been nice to work with," Powers says. "A parking structure of this size doesn't lend itself to the use of flying table forms. This approach is more cost effective and more efficient."

Once forming is complete, rebar and post-tensioning cables are placed in position. The slab is then completed in a series of four individual pours of about 350 cubic yards apiece. The decks are finished with a raised swirl pattern, applied during concrete fishing, and the sequence then continues as work begins on the next level's columns, walls, forming, and deck.

Overall, about 10,000 cubic yards of 5,000-psi concrete will be used on the project. Most of it — about 6,000 cubic yards — will be structural concrete, with the remainder going into the foundation and into walls and columns. Atlanta-based APEC is handling the vertical forming, while United Reinforcing, Atlanta, is handling rebar and post-tensioning. Cherokee Pumping Services of Atlanta is taking care of concrete pumping.

As construction moves ahead, Atlanta-based Mayberry Electric, Savannah-based Morris Mechanical and Savannah-based Champion Fire Sprinkler will begin work on their portions of the overall project.

Across the board, one key to the project's progress has been its crane. Since space is so extremely limited, Powers says, a crawler crane was not an option. Instead, the contractor chose to use a Wolfkrane 325 tower crane from Morrow Crane of Atlanta with a 146-foot hook height and a 243-foot-long jib.

"Because there is so little room," Powers says, "it was necessary to select a single crane that could serve the whole site."

"And since it's the only crane on the project," Boyken's Smirl adds, "it is critical to the schedule. In fact, the schedule runs through the use of the tower crane."

Throughout the project, another overriding consideration in planning and execution has been the site itself. Locked in on all sides, it offers very little room for laydown, storage or equipment. Virtually every aspect of the project, from scheduling and crew size to material delivery to the type and size of tower crane, has been dictated by the nature of the site.

Safety has been a constant focus on the project, with daily toolbox meetings, weekly project-wide safety meetings and regular job site inspections all serving as part of the overall safety program. Milestones are celebrated by monthly barbecue lunches for the entire construction team, and the effort is paying off.

"To date, it has been an incident-free project," notes Mortimer.

How has the construction manager approach worked out on this project? There is general agreement that is has worked out very well.

"Having a construction manager on the project means that the contractor has someone to go to immediately," says Boyken's Stein. "As the program manager here, we take care of dealing with the city, and we know what to do to get an issue resolved."

Adds Mortimer, "It is much better for the contractor not to be worried about the bureaucratic process — and that lets the contractor keep focused on what the contractor does best."

Another advantage, he adds, is that "you've got an extra set of eyes and ears on the job at all times. As the construction manager, we play a quality assurance role at all times." That minimizes problems, he says. "And if the contractor has a nice short punch list at the end of the project, then everyone is happy."

Archer-Western's Powers on the project agrees.

"This has been a good experience," he says. "Boyken handles construction management, and that lets Archer-Western handle construction."