This article is excerpted from an article from Ascent Magazine.
While multifamily building owners have been developing the space on top of parking structures for some years now, owners of commercial projects are just beginning to maximize the potential of that space with features such as athletic courts, swimming pools, built-in grills, and fire pits. The obvious purpose of such amenities is to attract new tenants, says Rob Smith, vice president and general manager for the Georgia division of Tindall Corp., the precast concrete producer for the ICON Buckhead parking structure profiled on the following pages.
Putting additional weight on top of a parking structure, of course, takes skillful design and engineering.
Dick Baumgartner, field services manager for Spancrete, the precast concrete producer for the Pritzlaff parking structure, adds, “As parking structures continue to evolve, it is vital to consider multi-use structures within your current layout.”
“Building owners are trying to make parking structures more attractive to get the desired clientele to rent from them,” says Smith. A well-planned and executed rooftop space can not only help recruit talented individuals, but also improve employee retention, especially in occupations that involve high stress and long hours. A roof transformed into a park-like setting with gardens, pergolas, and benches helps people connect to the outdoors and nature. Generally, a green roof helps building owners meet their sustainability goals.
Other building owners opt to create an attractive space for company events that can also be rented out for private parties. The Pritzlaff parking structure has a patio with built-in gas grills, LED rope lights, and a concrete floor that looks like multicolored pavers but is much more durable.
It’s important to consider views from the top of a parking structure. This is particularly true in urban environments that are becoming increasingly dense. The 10-story parking structure at ICON Buckhead complements the adjacent high-rise tower. Due to careful site planning and orientation, the parking deck captures vistas of the surrounding green space by day and the panorama of city lights by night.
Putting the additional weight on top of a parking structure, of course, takes skillful design and engineering. “You have to manage the tension between what the structure demands and what the architects want to have on top—how you distribute the loads and how it affects parking and retail space [within the structure],” says Smith. “Then you have to find the most economical way to achieve the owner’s desires.”
The installation of rooftop amenities may require specialty contractors, and it can be expensive. This is where precast concrete shines: in the savings it offers on the overall cost of a parking structure and the time it takes for completion. As Baumgartner notes, because the construction of the Pritzlaff parking structure took half as long as cast in place, “[the owner recognized] revenue and occupancy much sooner than originally planned.”
Large Project, Small Footprint
The ICON tower, in Atlanta, Ga., will have 363 luxury apartments and 32,000 ft of street-level retail and office space, served by a two-bay, 10-level, precast concrete parking structure. The amenity space on top of the parking structure was an intricate build, Smith says, including a swimming pool, pool terrace, waterfall, fire pit, and bars centered around views of the Atlanta skyline.
The owner, Related Group, needed sufficient parking to support the tower, and it had to be built quickly and under budget while providing plenty of exterior appeal, handling the weight of the complex rooftop amenity space, and accommodating future horizontal expansion of the deck.
Conditions were extremely tight as the ICON property was shoehorned between an active restaurant, a critical highway, a parking structure, and two adjacent roads in a central portion of the affluent Buckhead neighborhood.
The large project had to fit in a small footprint with physical constraints on all four sides, including a sloping site. Yet the structure had to be aesthetically pleasing and meet the owner’s The roof-level pool and terraces of the ICON Buckhead parking structure have geometric design that mimics the angular shape of the parking structure. Photo: Gregory Campbell/Picture Productions.s, Tindall used two colors of concrete within a single panel. The architect, Smallwood, Reynolds, Stewart, Stewart & Associates, worked closely with the precast concrete producer while evaluating multiple façade options. The enhancements were accomplished within the owner’s budget, including various colors and exterior finishes as well as cantilevered planters, façade panels, and other elements.
“[Precast concrete allows you] to do stuff offline away from your critical path, and absolutely compress the total cycle of construction,” Smith says.
Engineering and Other Challenges
One of the things that makes the parking structure unique is the complex cross ramp bisecting the main litewall elevation. In addition, the amenity space was an engineering challenge due to the loads and aesthetic goals of the owner. Tindall designed precast concrete planter boxes that were countersunk into the double tees in the rooftop space.
Because the site was so constricted, Tindall had to employ an assist crane to pick up and rotate trailers after delivery of the precast concrete to the main crane. While the parking deck was under construction, so was the 35-story apartment tower abutting it. “This required coordination to assure a safe, effective build,” says Smith.
Related originally planned a cast-in-place parking structure, but Tindall and Gilbane convinced them that precast concrete was more cost-competitive and would dramatically decrease the overall schedule. The general contractor saved many months on the project, says Smith.
At press time, the ICON Buckhead site was still under construction, with a two-year time frame for completion.
Susan Bady is managing editor of Ascent magazine. She can be reached at susanbady@gmail.com