Historic Charm, Modern Construction Technology
The city of Winchester, VA, is constructing a parking structure that will incorporate some unique design and precast technology. The project began at the end of May 2008 and is on target to be completed by mid-April 2009. The $7.68-million project plans to use approximately 25 million pounds of concrete. Upon completion, this new parking structure will have some 540 parking spaces spanning five levels.
Howard Shockey & Sons, Inc. is the general contractor and its sister company, The Shockey Precast Group, is responsible for the engineering, manufacturing and erection of the precast on the project.
The design and construction of the Winchester parking garage is preserving the integrity of the historic area on Winchester's Kent Street corridor by following a design that will meld into the intended architectural look. Yet beneath its aesthetics it will employ modern construction techniques using state-of-the-art precast construction with an embedded façade. This has been an architectural challenge in the revitalized historic district in Winchester. It challenged architects to integrate infill projects that complement each other, while incorporating a style that reflects both old and new. This has been part of a careful shaping that ensures that new buildings will be a contextual fit architecturally and also will meet local design review standards.
"The exterior appearance and architectural aesthetic of the structure will greatly enhance the Kent Street corridor, furthering the improvements that began with the OakCrest Company headquarters and numerous other projects within the neighborhood. The combination of adaptive reuse of existing structures and thoughtful new construction works beautifully," says Jeff Boehm, a vice president with Howard Shockey & Sons, Inc.
The OakCrest Company headquarters is another Howard Shockey project located just down the street from the Winchester parking garage project. It was one of the first projects along this urban corridor and was converted from a partially condemned historic knitting mill that was turned into a corporate headquarters. This particular project catalyzed the revitalization of Kent Street in this section of Winchester.
"As far as our design goal, we were trying to blend in with the historic fabric of downtown," says Tim Machado, AIA, of Design Concepts, the architect for the project. "The challenge was, 'How can we provide a good-looking parking structure in the historic district?' The way we achieved that was to look at the common architectural features of nearby buildings. We worked closely with Howard Shockey & Sons and The Shockey Precast Group to formulate panels that could replicate those common elements in terms of texture, color and thickness."
Machado says that his firm worked closely with Howard Shockey & Sons on the precast thin-set process of producing the precast concrete, which was intended to improve on the delivery schedule over the traditional hand-applied masonry method. "The stamped concrete base, which switches to a thin-set brick, combines to replicate common details seen in a historic district which was built on a limestone foundation," adds Machado.
The project followed standard phases of construction. The project began with site work, followed by installation of caissons. After footers had been constructed, precast erection began. The final stages of the project will include elevator construction and installation followed by installation of control equipment and signage.
"First came the site work — the site used to be a county parking lot," says Gary Ball, project manager with Howard Shockey & Sons. "All site waste was taken to another building site by the site contractor and used as fill. Then 82 caissons were drilled down into solid rock. Now we are in the precast erection phase."
Erecting the precast can be a daunting task, according to Ball. "Some of the individual pieces weigh 30 tons," he says. "On average, approximately 12 pieces are moved into place daily. There is a 300 Demag crane on site set up with a 100-foot boom and a 120-foot jib — providing 220 feet of stick in the crane."
The precast members employ some unique technology, says Ball. "The precast includes carbon fiber (C-grid) reinforced double tees that help make the structure lighter and stronger," he explains. "Stainless steel fasteners are being used on the project. Both the carbon fiber and the stainless steel are non-corrosive, thus eliminating what is often a parking garage owner's biggest maintenance headache — problems relating to corrosion."
The cladding for the project will be installed as the precast is erected. "The first two levels are clad with stone-faced masonry with thin-set brick above," says Ball. "Both the stone-faced masonry and the thin-set brick are cast in the beds."
Ball explains that this is advantageous in at least two ways. It reduces the construction schedule, as there is no hand cladding after precast is up since both are done concurrently. It also reduces safety risks because it eliminates the need for workers to apply cladding at higher levels.
Ball mentions that the project has its challenges. The parking garage is located between the Frederick County Office Building and the recently rehabilitated historic George Washington Hotel, and historic preservation standards were an issue. One corner of the parking structure is in the historic district and had to go through a Board of Architectural Review.
"The design and the cladding respect the scale, materials and history of the old town district," he explains. "The uses of brick arches complement the structure's neighbors and the historic district as a whole."
But Ball feels that the greatest challenges thus far were getting the 82 caissons drilled and in place. "You never know what you are going to hit when you start drilling," he says. Because the areas were characterized by limestone formations, there were karsts or irregularities where erosion has produced sinkholes and underground cavities. "In this area with its limestone karst formations, it can get a bit tricky."
Otherwise the project has been going smoothly; however, the constraint of historic preservation is ongoing. "We also have the challenge of construction in a historic district with tight site constraints," he says. "We are building property line to property line, moving east to west and eventually it will get tighter and tighter to work. This is not necessarily too unusual, but it is a challenge."
With a design that integrates into the charming and historic city of Winchester, the new parking garage scheduled to be ready for use in the spring of 2009 will add to the city's current 1,789 parking spaces, presenting an architecturally fitting design while employing contemporary construction technology to produce it.