Southlake, Texas, northeast of Fort Worth, is the new home of Sabre, a leader in providing technology and online services for the sustainable travel and tourism industry. The project consists of two similar concrete-framed office buildings—one four stories, the other five—and a five-story cast-in-place concrete parking structure for 1,800 vehicles. Together, this first phase has approximately 1.1-million-square-feet office and parking space.
In the initial planning stages, Sabre wanted something different in the new facilities that would set the company apart. In particular, an environmentally friendly, comfortable workplace was sought that offered numerous amenities for Sabre employees. It was also important to have clear, open floor plans that would give Sabre the freedom to set up and subsequently rearrange work areas as required. Finally, the new headquarters had to be a marketing tool that would attract the best and brightest workers. All of these requirements were met with a concrete framing system.
Typical bays in the office buildings are 30-by-55-feet. Spanning in the 30-foot direction are wide module joists comprising 4-3/4-inch thick slabs on 66-inch wide by 20-inch deep pans, with 10-inch wide ribs, spaced 6 feet 4 inches on center. The joists are supported on 48-by-24 3/4-inch posttensioned girders, which span 55 feet. This long span floor system provided the column free spaces required by the owner. The columns are 24-by-30-inches for the entire height of the building. Lateral loads are resisted by the moment frames.
In the quest to provide environmentally sustainable construction, the owner and design team utilized the United States Green Building Council’s LEED® (Leadership in Energy and Environmental Design) program. This project, which is probably the greenest corporate office facility in Texas, is one of the first and largest in the United States set to receive the LEED Silver Level Certification. In keeping with the LEED requirement on the use of recyclable materials, the concrete mix contained fly ash. A 5,000-psi mix is utilized for both the floor members and the columns. This was one of many requirements that were implemented to significantly reduce or eliminate the negative impact this project would have on the environment and its occupants.
In addition to the green construction aspects, concrete framing was chosen for other reasons. Overall cost was one of the main factors, it was determined that structural steel framing would have resulted in a floor system that was 5 inches deeper than the concrete system. This, along with fireproofing that was required for the steel, would have increased overall costs significantly. Also, since this was a high-profile client, the structure needed to be high quality with superior performance. Exposed interior concrete is used throughout the facility. Furthermore, vibration of the long span floor system is not an issue with concrete framing. Finally, Sabre needed to move in as soon as possible. Even though the LEED program was utilized, the facility was occupied as planned.
Sabre, Southlake, Texas
HKS, Dallas, Texas
Structural Engineer (Buildings):
Brockette Davis Drake, Inc., Dallas, Texas
Structural Engineer (Parking Structure):
HKS, Dallas, Texas
The Beck Group, Dallas, Texas