The flexibility of precast concrete components is on strong display at the new Fort Hill Activity Center. Load bearing and insulated, precast exterior wall panels facilitated the design by providing the mass needed to balance expansive glass, by meeting stringent sustainability demands, and by working to emulate or accommodate other building materials utilized. Precast components were also used for an adjacent underground storm water retention tank.
Built on a 5.2-acre site, the 79,575 sq. ft. Fort Hill center includes 23,070 sq. ft. of gym space and running track, 8,860 sq. ft. of group exercise rooms, an 8,683 sq. ft. fitness center, 6.440 sq. ft. of multipurpose rooms, and 5,825 sq. ft. of gymnastics space.
The first floor of the building offers four high school-sized basketball/volleyball courts, setups for badminton and pickleball, gymnastics space, a café, four multipurpose rooms for arts and crafts, weight training machines, locker rooms with 178 lockers, and an indoor playground with a two-story slide. Second floor contains a 12-foot-wide walking/jogging track, three group fitness studios, and cardio equipment such as treadmills and cycles. Gymnastics equipment includes a balance beam, parallel and uneven bars, rings, and a foam pit. Also included are wood floor studios for dance or group exercise, meeting rooms, offices for park district staff, a child care room, and dedicated spaces for those with special needs, as well as 332 exterior parking spaces.
Mass to balance glass
One façade of the building features a sweeping, curved wall of glass. Behind the glass is the two-story fitness center showcasing the exercise and weight equipment.
"We wanted the design to be welcoming, create an identity for the Park District and emulate the exceptional level of service It is the Park District’s first multi – generational community recreation center," says Frank Parisi AIA, LEED AP BD+C, Principal, Williams Architects. "We strategically placed glass on the main approach to the building to celebrate activities inside. Driving up to the building you know exactly what is going on inside. Approaching at night, the visual imagery is even stronger. During the day, patrons can look out and enjoy the outdoors and natural light."
"But from a design perspective," Parisi adds, "you have to offset all the glass with some sort of mass or anchor. The largest volume space within the building is the gym and gymnastics area. We utilized [load-bearing] precast [wall panels] here to express mass. The precast served both the aesthetic and the function. The panels were load bearing and help reduce the energy by employing them as thermal mass."
"The design is reflective of the Park District’s mission toward sustainability. The team adopted sustainable concepts using the LEED Guidelines. The design included natural lighting strategies while recognizing energy use within the building. The precast element contributed in two ways. From a design perspective it balances the glass and the mass. From an economic perspective, it gave us the sustainability parameters [i.e. high R-value, thermal mass] needed.
Designed to LEED Silver-plus Guidelines
Deciding on precast construction, the architects wanted to develop a creative interpretation of precast utilizing standard forms. Williams Architects worked closely with Dukane Precast to come up with the correct cross section of the insulated precast wall panels that would give them the best return on investment.
The precast panels on the Activity Center feature a formliner and smooth exterior finish and a hard steel trowel interior. The panels are 12 feet wide with heights varying from 17 to 44 feet tall and were produced as standard grey panels and then painted in shades of grey. The 12-inch-thick panels feature interior and exterior wythes of 3-1/2 inches and a 5 inch core of insulation and provide an R-21 nominal rating.
The use of precast construction also enhanced the project’s sustainability by offering long term durability and fire resistance. The panels utilize recycled steel reinforcement and include fly ash in the mix. Moreover, the precast components do not produce VOCs, contributed little to construction waste, and were locally produced.
The building, says Parisi, features a super-insulated envelope and is designed to meet "at least" LEED Silver guidelines.
In addition to the insulated wall panels, the structure’s reflective white roof system provides six inches of polyisocyanurate insulation with close to an R-40 rating. Other sustainable features include a high-efficiency HVAC system, the latest LED lighting units, and permeable pavers. The use of daylighting is a main sustainable feature. Included are large windows throughout and 40 tubular lighting units in the roof of the gym and fitness center. These bring in natural light, reduce energy use, and provide views to the outdoors. There are occupancy sensors that control lighting. The building also features daylight harvesting on all perimeter glass so that perimeter lights dim when day light is adequate.
Finally, 117 photovoltaic solar panels were installed on the roof of the activity center. The 33.35 kW system will generate approximately 40,000 kWh of energy annually, account for a reduction of nearly 76,000 lbs. of carbon dioxide, provide an estimated 5.36% of the total electricity used by the Center, and result in an annual cost savings of $4,800.
Precast flexible, compatible
According to Parisi, another main advantage to the use of precast construction was the compatibility of precast.
"We have metal panels on the building and precast was flexible enough with color variations and reveals that we could emulate [the metal] cost effectively. We used a formliner to get a deep corrugation to mimic the modulated panels. Precast also gives you the flexibility to put windows in, even vast expanses of them, without increasing the cost of the structure."
According to Wight Construction, the Activity Center was also required to have full on-site water detention to address storm water and erosion. Because of the site, it was initially thought that the detention pond would need to be very deep and include double retaining walls and guard rails for safety. After re-evaluating the basin design with the precaster, it was determined the basin could be mainly underground, located beneath the parking lot, and require only a shallow detention area above ground.
Provided by Dukane, precast panels for the storm water tank are 10-inches thick and 6-1/2-feet tall (laid horizontally) with lengths varying from 10 to 25 feet long. Precast double-tees for the tank top measure 10 feet wide with a span of 35 feet.
The Fort Hill project broke ground in April 2015 and opened in August 2016. Precast panel erection time for the building covered just nine days. Precast erection time for the storm water tank took just three days. According to Parisi, the project came in under budget and right on schedule.
The $24,120,000 Fort Hill Activity Center was named "Project of the Year" by the American Public Works Association (Fox Valley Branch) and was presented an "Outstanding Facility" award by the Illinois Park and Recreation Association.
"Fort Hill," says Brian Bock, VP of Sales & Marketing for Dukane Precast, "was the biggest project completed by the Naperville Park District and, as indicated by its recent awards, has been recognized by its peers as a true state-of-the-art facility and as a great combination of precast concrete and open glass."