Architect of Record: Overland Partners
Structural Engineer of Record: Datum Gojer Engineers
Mechanical Engineer: HMG & Associates
Civil Engineer: Davcar Engineering Services / Urban Design Group
Construction Manager: SpawGlass
Reinforcing Bar Fabricator: D’Ambra
Total Project Cost: $69 million
Total Project Size: 213,000 sq ft
Award: 2013 CRSI Award Winner – Educational Facility Category
STRUCTURAL FRAMING SYSTEM
The College of Liberal Arts, University of Texas at Austin is a tremendous example of the power of teamwork leading to extraordinary results. Through a highly collaborative process, the design and construction team made decisions together to produce an extremely efficient, effective, adaptable building design.
The project’s architect, Overland Partners, set a high bar for the team to deliver this project with the most efficient building possible. From the beginning, their leadership led to a highly collaborative process. Knowing that repetition and modularity were the best ways to maximize the efficiency of the building, Datum Gojer Engineers, set out at the beginning of the design process to conceive a very regular, repetitive structural system.
Collectively we pushed for this idea at the earliest design charette meeting with the team, and the idea caught on. A 10′-8″ module was conceived for the building, using a mix of 32′ and 42′-8″ bays. From there, we performed a formal structural system selection study to ensure that we would use the most efficient structural system for this project given the time, location, and market conditions.
Based on this study, the cast-in-place (CIP) reinforced concrete system proved to be the least expensive system by itself. In addition, the reinforced concrete system had lower costs for miscellaneous metals, and no premium for lateral stability. It also required a shallower floor-to-floor height, resulting in significant savings by eliminating 6 feet of skin from the height of the building, along with associated long-term energy savings. All of this, combined with its inherent durability and superior vibration performance characteristics, made reinforced concrete construction an obvious choice for this project.
By stretching the bays a little bit for the 32′ and 42′-8″ spans, and cantilevering the perimeter bays 12 feet, we eliminated as many as 20 columns and piers from the building design, saving time and labor in the project. In addition, space planning around the perimeter of the building was made more efficient by eliminating the perimeter columns. At the ground floor the building enclosure was held back from the cantilever, which had the added benefit of allowing the upper floors’ cantilevered perimeter to provide shaded walkways adjacent to the building.
UNIQUE DESIGN FEATURES
At the heart of the concept is a flush-bottom, 25 inch-deep reinforced CIP concrete skip-joist (super-wide-pan) or beam-and-slab-system (5″ thick slab + 20″ deep pans framing system with 12 feet cantilevers on all four sides of the building. Taking advantage of form re-use, the main roof was also framed using this same concrete system and was designed to accommodate future green roof load.
For efficiency, all building systems including the structure were built around a 10′-8″ module. Joist ribs are spaced at this same 10′-8″ on center, and are 18″ wide. This allowed the contractor to base their formwork for the joist ribs off of a pair of 53 inch wide pan forms with a four inch nominal filler, for a total void between ribs of 9′-2″.
Concrete design elements, such as the four exposed architectural reinforced concrete exposed connecting stairs, contribute to the beauty, functionality, and success of the project. Through a commitment to this integrated design process, the team produced a building that provides 17% more usable space than the owner expected, at a saving of 13% from the original project budget, allowing the College of Liberal Arts to keep more programs intact in an era of cutbacks.
REASONS FOR CHOOSING REINFORCED CONCRETE
- Use of reinforced cast-in-place construction for economy, flexibility, speed of construction, and longevity.
- Flush bottom framing construction for maximum economy of forming.
- Highly modular framing layout conducive to re-use of forms for maximum economy of framing.
- Cantilevered end bays around all four sides of the building to avoid inefficient end spans, and to open views around the perimeter. This reduced the number of piers and columns by as many as 20.
- Exposed reinforced cast-in-place concrete cantilevered switchback stairs for beauty and functionality in uniting all floors throughout the height of the building.