Indoor-Outdoor Design

For this high-profile project, executives with the NBA franchise were seeking a facility that reflected the local community.

“From the beginning, we set out to build an arena that was iconic, that represented the best of Sacramento and that would provide for the best possible fan experience,” says Chris Granger, president of the Kings. During the design process, 20,000 Sacramentans expressed their opinions via a series of workshops, open houses and focus groups.

Los Angeles-based AECOM took on the challenge to design a space that connects to the outdoors in an urban environment known as “the city of trees.” AECOM worked with general contractor Turner Construction, which also recently built Levi’s Stadium in Santa Clara for the San Francisco 49ers, and ICON Venue Group, which represents the ownership team of the Sacramento Kings and the city of Sacramento, to incorporate a number of “firsts,” according to project officials.

For example, five operational 40-ft high, bifold hangar doors serve as the focal point of the 17,500-seat arena. First, Turner installed metal frames at a 10-degree angle above the entry doors. Crews then used three 50-amp motors—which will operate each door after completion—to install the 27,000 lb of glass on each opening. “This was the first use of levered glass doors like this on such a large scale,” says Alastair “Aly” Mac- Gregor, AECOM vice president.

The building orients to face a public plaza to the south so the glass is shrouded during Sacramento’s 100-degree summer days. Fretting, in the form of dots applied to the glass after installation, provides shading and eliminates glare on the outside while preserving the transparent connection to downtown. “It looks as if sun is coming through trees,” MacGregor says.

When open to the delta breezes, the doors offer a natural cooling system. The operation of the doors can be controlled via a tablet app that takes into ac- count wind and temperature conditions and sends an alert when conditions are ideal. “But it is a person who makes the decision whether to open them,” MacGregor adds.

The open-air option brought its own challenges, according to Rob Rothblatt, AECOM architecture design principal. “Kings ownership had to be able to guarantee the NBA that the floor would maintain a constant temperature and humidity so it wouldn’t warp, even with the hangar doors open.”

To solve this, designers incorporated two separate ventilation systems that can be controlled independently. Three 67,000-cu-ft-per-minute (CFM) air-handling units serve the lower bowl via a low-pressure, high-volume displacement air ventilation system distributed around the entire lower bowl from portals under the precast seating. The upper bowl is served by three 55,000-CFM custom air-handling units through a common ring of distribution duct with a diameter up to 48 in. Openings up to 104 in. wide and 52 in. tall provide return air to the upper bowl air-handling units.

This arrangement results in more air vents than a traditional overhead duct system, but requires smaller handling units, thus saving energy and potentially increasing operational flexibility. It is also more effective than evaporative coolers because they would not have solved the problem of humidity with a significant load of perspiring fans.

“We believe that it is at least the first use of this configuration within a professional venue, and likely the first in an indoor sports venue,” says MacGregor. “It has been used internationally; however it has not gotten traction in the U.S. as fan comfort and energy consumption have not historically been primary design goals.”

Where the glass doors leave off, lightweight, 3D aluminum sheeting adorned with a leaf pattern brings natural elements into the arena at a more human scale. “The undulations make a large building seem smaller,” says Rothblatt.

The installation was challenging. “We had to take into account contraction of the glass and metal due to extreme temperature swings,” says Gene Fatur, senior project manager for Turner. A circle of 12-in. by 6-in. structural tube steel comprises 65-ft-tall, 10-ft-wide vertical “ladders” that frame the bowl. Crews then used clips and bolts to fasten the aluminum panels—etched with a leaf pattern by subcontractor Kovach Building Enclosures—to the ladders.

“We use Point Cloud scans to connect within millimeters so glass doesn’t crack and aluminum doesn’t tear,” says Turner’s Dai Zovi.

Erection of the exterior ladder and high roof steel was finished in July, with steel topping out in October. The curtain wall installation wrapped up at the end of March.

Connected Facility

Kings’ owner Vivek Ranadivé—the former CEO of soft- ware company TIBCO—insisted on a commitment to 21st-century technology, and especially placed a premium on Wi-Fi bandwidth. As a result, the arena will feature 1,000 Wi-Fi access points for around 17,500 seats, enough connectivity to accommodate 50,000 Snapchat posts per second. Beacons located throughout the stadium will ping attendees’ phones with info such as where to find the shortest restroom line.

Access points for cabling and equipment were built out early in the construction, but installation was scheduled to occur at the last minute to ensure that the most innovative technology available was used so it would not be outdated before the center opens. The effort "future-proofs" the facility, according to a Kings spokesman.

Crews placed the concrete for the 60-ft by 114-ft arena floor in a single placement, using a laser power screed to ensure flatness. A 6,100-sq-ft video board—the size of a semi-truck—hovers over the floor from a winched rigging system and displays via 32 million pixels.

MacGregor expects the building to earn a LEED Gold rating. “We applied some of the sustainability concepts learned in the design of the London Olympics and Barclays Center in Brooklyn, where AECOM did interior design,” he adds.

Granger says the building could act as a model for sustainability in the sports industry due to features such as “the usage of 100% renewable energy, to the near complete usage of local sourcing in our concession programs, to smart water conservation strategies.” For example, a living wall garden of local plants and edibles uses drip irrigation connected to water runoff collected from the roof.

In the back of the building, a four-truck bay accommodates dual use of the stadium as an event center that can handle large concerts.

In addition to the stadium itself, the project includes a practice facility, four blocks of retail and office space, curving around the facility to pull traffic into a new plaza.

“We now have an arena that is open (literally and figuratively), a building that respects our environment and celebrates the geography of the region, and one that anchors a grand civic space, irrespective of whether or not the Kings are playing,” says Granger.