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Known primarily for its use as a soil stabilizer in transportation projects, expanded polystyrene (EPS) geofoam is now being viewed by engineers and contractors as the material of choice for an array of other commercial applications.
With high compressive strength, light weight, and predictable performance, geofoam is appealing for reducing weight on concrete decks, creating green roofs, providing fill for floor elevation changes and landscapes, or reducing lateral pressure on foundations and retaining walls.
Geofoam has also earned accolades because it can be manufactured to precisely meet design requirements and accelerate construction schedules. It can be used for foundations and sidehill fills, reducing lateral pressure and also reducing axial loads on structures because of its light weight and predictable physical properties.
Now that the construction and engineering communities have had years of exposure to geofoam and continue to explore its use in commercial applications, it is among potential solutions in meeting design requirements for schools, hospitals, institutional buildings, athletic facilities, and civic revitalization projects.
A+ for adding school amenities
Administrators with the Jenks (Okla.) School District decided to include a planetarium at their new math/science facility.
The new planetarium was designed for the rooftop of the new math/science building. The project called for a 6in.-thick finished concrete slab, elevated 12in. above the concrete roof slab, which would serve as the finished floor of the rooftop planetarium.
Six inches of geofoam provided the void fill needed for the elevated floor slab, a 60ft-diameter circle with a 16ft-wide connecting hallway.
Under construction: Hallway leading to the planetarium.
Geofoam void fill installation under the planetarium’s elevated floor slab.
Circular trenches were cut into the geofoam to achieve thicker slab areas that provide support for the inner planetarium dome. According to Bob Tolomeo, project manager with Lithko Construction, “The availability, cost, and ability to order the geofoam in full 6-in. thicknesses aided Lithko in maintaining the desired construction schedule.
“Due to the cutting that was needed to achieve the circular shape and trenches, the single layer of EPS 46 made placement much easier,” he said. The use of EPS geofoam also helped Lithko meet its Leadership in Energy and Environmental Design (LEED) requirements.
The new 90,000sf math/science facility at Jenks High School was completed in the fall of 2010. Four-ft x 8-ft sheets of geofoam provided the void fill needed to elevate the floor slab. The Jenks planetarium dome is about 66ft in diameter, almost 26ft tall and weighs 10,300lbs.
The dome was assembled on the ground. A 250-ton crane hoisted the dome into its final location. The new three-story building includes four science prep rooms with fume hoods and water purification systems, four 50-ft wind turbines tied to the building’s electrical grid, and geothermal energy to heat and cool the building.
The completed planetarium on the rooftop of the Jenks High School math/science facility.
Green spaces add aesthetic value at Washington U
Not only are educational facilities adding amenities for students, they are also sprucing up aesthetics to create inviting outdoor spaces.
A reflecting pool and plaza with native landscaping welcomes visitors to the BJC* Institute of Health at the Washington University School of Medicine in St. Louis, creating an expansive and welcoming green space in the midst of the school’s medical campus.
The reflecting pool and plaza were built over an existing below-grade parking garage. EPS geofoam was used to lighten the load on the below-grade structure, raise the fountain area, create sidewalk elevation changes, and fill planters.
The main entrance walkway connects the building to the metro public transportation platform and is one of the most heavily traveled pedestrian routes in the city of St. Louis. Emergency services are critical to this route, and geofoam became a component to making the area accessible.
Geofoam installation in the plaza for the BJC Institute of Health at the Washington University School of Medicine in St. Louis.
The vertical elevation constraints of the walkway are designed to support a fully-loaded fire truck while limiting concrete cracking. The walkway design features an exposed aggregate-reinforced concrete slab placed in two bonded layers, which are supported on EPS 39 geofoam.
About 500cy of geofoam were installed in two different walkway areas to limit the total weight placed on the structural roof slab below. The planter areas are designed similarly to the fountain—raised above the sidewalk and incorporating stepped-up layers to create a three-dimensional surface.
Geofoam installed in and around the circular reflecting pool at the BJC Institute courtyard.
The light weight and high compressive strength of geofoam also helps to protect water pipes that lead to the reflecting pool.
The design of the project was difficult due to the sloped and tiered architectural elements. Geofoam was originally fabricated with a radius edge; however, due to the cost it was changed to a square-edged layered system to accommodate the tiered radius sections.
Two types of geofoam (EPS 22 and EPS 39) intersected and were designed to meet the engineer’s drawings. A total of 24,500sf of geofoam completed the plaza renovation in early spring of 2010.
The three layers: 1st layer (4-1/2” sheets), 2nd layer (tapered beds), and hill layer (EPS 39pg).
The finished courtyard for the BJC Institute of Health at the Washington University School of Medicine in St. Louis.
*BJC HealthCare was created in 1993 when Barnes-Jewish Inc. merged with Christian Health Services to create a system consisting of a large urban teaching facility and a network of suburban community hospitals. In 1994 Missouri Baptist Medical Center and St. Louis Children’s Hospital also joined BJC HealthCare.
Performing arts complex revitalizes KC arts district
Located in downtown Kansas City, Mo., in the Crossroads Arts District, the new Kauffman Center for the Performing Arts is the home to three of the region’s leading performing arts organizations: the Kansas City Ballet, the Kansas City Symphony, and the Lyric Opera of Kansas City.
The Kauffman Center has been described as one of the most technically and architecturally advanced performing arts centers in the nation. With a grand opening Sept. 16-18, 2011, the 285,000-sf facility includes the 1,600-seat Helzberg Hall, 1,800-seat Muriel Kauffman Theatre—each with its own acoustical envelope—and a 1,000-car underground parking garage.
An overarching shell houses both performance venues. A glass roof creates a series of interior piazzas that serve as shared public spaces. The Kauffman Center’s grounds are used for outdoor performances and public gatherings.
Kauffman Center for the Performing Arts, downtown Kansas City, Mo.
The rooftop of the parking garage adjacent to the Kauffman Center provides the outdoor space needed for performances and gatherings. To create the green-roof space, engineers required a lightweight fill material that would reduce the weight of the space on the parking structure.
The Kauffman Center’s parking garage is located on the south side of the building.
Geofoam installation on the rooftop of the Kauffman Center parking garage.
Geofoam was used to fit the compound sloped concrete roof deck of the parking garage and created a compound sloped top surface for the park. Over the geofoam in the park, grass, walkways, and trees were installed to create a spacious green area. Geofoam—350,000cf of EPS 19—plus a termite resistance treatment were installed in thicknesses ranging from 12in. to 14ft. Approximately 118 truckloads of geofoam were used to complete this project.
Geofoam was used to create elevation changes in the park’s grass areas and walkways. The tires are used to hold the geofoam in place during installation should high winds disturb the jobsite. The tires were removed prior to placement of soil backfill.
Roofing membrane installation covers the geofoam layer on the Kaufman Center parking garage.