California Universities Embrace Cool Style

CALIFORNIA UNIVERSITIES EMBRACE COOL STYLE

THE SUBSTANCE OF STYLE IN CALIFORNIA ADVANCES USING PRECAST CONCRETE FOR HIGH-SEISMIC REGIONS

BY MONICA SCHULTES

As population and urbanization increase in California, more people are living and working in active seismic regions. The challenge is to help protect life and property of what will soon be 40 million people living in the state. The design of resilient buildings relies not only on sophisticated analysis but also advanced, reliable options in materials and structural systems like precast concrete technology.

California State University at Sacramento and San Francisco State University used precast concrete in different forms to create beautiful, resilient structures that can withstand major events such as earthquakes, floods, hurricanes, heat waves, wildfires, and mudslides.

Left: Parking Structure 5, California State University– Sacramento Photo: Kyle Jeffers, courtesy of Dreyfuss + Blackford Architecture.

Parking Structure 5, California State University, Sacramento

The new six-level parking structure at the entrance to California State University in Sacramento is no ordinary 1750-space garage. Using the collaborative design-build delivery method, the project team succeeded in keeping the focus on the needs, comfort, and experience of the user. “We focus on the people aspect of the structure, not a garage that only stores cars,” explains Jason A. Silva, partner/design principal with Dreyfuss + Blackford Architecture in Sacramento.

Collaborative design-build is a process that Dreyfuss + Blackford has championed, especially with universities that need to deliver big projects quickly. The process, which combines the best of construction management at risk and traditional design-build, allows the owner to play an important role in the early stages of design while guaranteeing maximum price at the schematic design phase.

The relationship works well for precast concrete, given the front-loaded design. “Working with Clark Pacific, our whole approach was how to make the best garage using precast concrete. We were able to create an open and airy structure that was only achievable from the beginning, rather than redesigning for precast,” says Silva.

See the Forest and the Trees

Aesthetics were of paramount importance to the university because the parking structure is a gateway to campus and nestled into their arboretum. To play off the plethora of trees on university grounds, the design concept features green metal fins in a random pattern to mimic leaves. A custom formliner was selected to emulate the grain of tree bark.

“Ultimately we wanted to maximize the randomness as well as the efficiency and flexibility of the design features. The woodland elements were also conveyed through the unique formliner module that spread evenly over column and bay spacing,” says Silva. “The result gives an illusion of scalloping. The form relief on the columns stops to break up the lower half of the building and to maximize the efficiency of a single length of master formliner.”

The bay spacing was adjusted on the hybrid moment frame (HMF) lateral system to achieve uniform 24-ft column spacing consistently throughout. A typical parking structure entrance opening forced an irregular column spacing in the transverse direction. “The innovative solution here was to create a rhythm of columns. Take that 60-ft module and place the moment frame columns at 20 ft on center,” says Farid Ibrahim, director of preconstruction services for Clark Pacific in West Sacramento.

They resolved the ingress/egress issue by offsetting the entry to the outside and realigning the drive aisles after entering the structure. The regular column spacing made the HMF even more efficient and maximized the parking layout.

Off Campus

The university wanted to minimize disruption and to bring the structure online as quickly as possible. At the time, there were five concurrent projects, three of which eliminated surface lots, making parking a premium. “We delivered the garage in nine and a half months from breaking ground to commissioning,” says Ibrahim. “We calculated that 5700 worker days were moved off-site in comparison to a cast-in-place concrete alternate. The urban campus would have been highly impacted by those additional trades driving and parking each day. Construction and education don’t mix well. The idea was to get it done as quickly as possible with the

least impact to the university. Offsetting trades to the manufacturing site helped achieve that goal.”

The entire campus was impressed at how fast the structure was erected with so little disruption. “Their jaws dropped when they saw the garage appear in a matter of weeks,” says Silva.

In keeping with university focus on sustainability and energy efficiency, ParkSmart goals were targeted. ParkSmart is the equivalent of LEED certification for parking structures. The project team also is pursuing a U.S. Resiliency Council (USRC) rating. The target gold USRC certification will demonstrate that the parking structure isn’t just a beautiful structure that was quickly built, but one that can withstand a major earthquake.

In addition to meeting code requirements, the HMF provides enhanced structural performance during an earthquake for the safety of the three occupant types: faculty, students, and employees. It was of value to the university that this structure was designed with seismic performance in mind.

San Francisco State University Mashouf Wellness Center

The striking new building at San Francisco State University is the new hub of the urban campus community for those who want to exercise as well as socialize. The 118,700-ft 2 facility features fitness and weight areas, courts, three studios, a sauna, two pools, and a large multiuse space that can host team activities as well as student events.

Located on a prominent intersection off Lake Merced Boulevard, the Mashouf Wellness Center (MWC) serves as a signature facility and campus gateway. The shape of the building reflects the triangular site, and the three main modules (natatorium, gym, and courts) of the structure reach out in different directions.

Wellness by Design

The façade features glass-fiber-reinforced concrete (GFRC) panels that are crisp and modern, reflecting both the university culture and the diverse activity within.

“We designed the GFRC panels to mimic a monolithic shroud covering. As you walk closer, you can read the vertical random scalloping texture along the façade. The vertical patterning of the GFRC creates shadows to hide the vertical panel joints,” describes Edward Kim, project manager and associate at WRNS Studio in San Francisco.

“GFRC has a very plastic nature and enables us to create crisp edges and shadows,” adds Kim. “We performed sun studies to observe how the shadow lines move across the façade of the Wellness Center.”

Three-Dimensional Modeling Promotes Precast Concrete Creativity

“In recent years 3-D modeling has become common and the process of conveying design ideas to precasters more streamlined,” explains Mark Hildebrand, president and chief engineer at Willis Construction Co. in San Juan Bautista, Calif. “Through CNC [computer numerical

control] technology we can create molds directly from computer models. GFRC panels are an attractive solution because it can manage elaborate shapes.”

The MWC features panels that are 12 ft wide and up to 30 ft tall. The panels seem to float and bear only on the second level. Hildebrand explains the panels had to handle out-of-plane bending for wind loads. GFRC frames are more flexible and can handle the rotation and movement of a seismic event. “Because the interiors are so wide open inside there is not a lot of floor weight, so the whole structure was not very heavy and fit well with GFRC,” Hildebrand explains.

GFRC panels are widely used in high-seismic areas, where their light weight and flexible frames enable the panels to accommodate large seismic motions. California Building Standards Code seismic requirements have grown more stringent and the panels on the MWC have to accommodate 4.8 in. of drift, capitalizing on the flexibility of the GFRC system.

Long-Term Well-Being

The university wanted a long-lasting building and precast concrete is well established for its durability, which is often not considered with sustainability or resiliency goals.

San Francisco State University has limited funding for construction and operations. “GFRC is very durable and low maintenance, and able to meet their goal of 50-year life. In this construction market where time is very expensive, it also makes sense to fabricate offsite,” says Kim.

Given its capabilities for large-panel configuration, as well as the ability to accommodate large drifts in seismic events, the conditions in California are ripe for GFRC. “When we first started using GFRC, our designs were very two dimensional,” recalls Kim. “With evolving CNC technology and complex 3-D modeling, we are seeing more creativity expressed through GFRC and precast.” ●

PROJECT SPOTLIGHT

PARKING STRUCTURE 5, CALIFORNIA STATE UNIVERSITY–SACRAMENTO

LOCATION: Sacramento, Calif.Project Type: Parking structureSize: 515,015 ft 2Designer: Dreyfuss + Blackford Architecture, Sacramento, Calif.

Owner: California State University, Sacramento, Calif.

Structural Engineer: Buehler & Buehler Structural Engineers, Sacramento, Calif.

Contractor: Clark Pacific, West Sacramento, Calif.

PCI-Certified Precast Concrete Producer: Clark Pacific, West Sacramento, Calif.

Precast Concrete Components: 6089 pieces, including double tees, spandrel panels, columns, beams, stair and landing units