The new library is envisioned as an important community connection in an emerging area of Austin that was formerly an industrial hub. © LAKE|FLATO, MOKA Studio
The eclectic city in Texas moves forward with a new central library that embraces an expanded community role in a digital future.
April 1, 2014—Few public institutions are experiencing as rapid and profound a change in their mission than the venerable public library. These once silent repositories of learning were designed to hold mountains of books, magazines, and newspapers. But as the public increasingly embraces digital reading material, the space once consumed by shelves is becoming open to reinterpretation.
A clear example is the new central library that the City of Austin, Texas, is building near picturesque Lady Bird Lake on the south side of its vibrant downtown. An energy substation once occupied the reclaimed site, which is adjacent to a former power plant that is being repurposed as a retail development. A residential tower is also planned nearby.
In total, five construction projects that will dramatically transform the former industrial hub into a modern urban neighborhood are now under way. The new central library is a key to the city’s plans for the area, which includes scenic Shoal Creek and popular bike paths.
“We had this charge from the city to make this a library of the future,” says Steve Raike, AIA, LEED-AP BD+C, an associate partner of LAKE | FLATO ARCHITECTS, in Austin. “We wanted this to be a very bright, open, connected space. Almost like a living room for Austin. You didn’t feel like you were walking through a maze of books.”
LAKE | FLATO partnered with library design expert Shepley Bulfinch, of Boston, on the design, which features a dramatic six-story atrium that will flood the structure with natural light. The design features a facade of Roughback Lueders limestone supplied by Mezger Enterprises, in Lampasas, Texas, that echoes the material used on the nearby city hall.
City leaders have been working since the mid-1990s to develop the project. The current central library was completed in the mid-1970s and is out of date both technologically and functionally, Raike says.
“Electronic delivery of information has become more and more accessible and more and more common,” Raike notes. “For us that meant that while the building still needed to house the collection, it could not simply be a warehouse for books. It had to be a building that was going to serve the needs of a community that honestly can get whatever information [it] wants, just about, in the palm of [its] hand.”
The design incorporates several community spaces, including a sixth-floor reading garden with dramatic views of the city, a cafe, a bicycle garage and repair shop, meeting spaces, and a 300-seat, two-story event forum. This forum will serve a vital role in the city, the developers hope.
Austin—the state capital and home of the University of Texas at Austin—is a dynamic city of approximately 850,000. The city claims title as the “Live Music Capital of the World,” has a growing film industry, and an impressive theater scene.
“The library system wants to be an active participant in all of those things,” Raike says. “They have a space there that will hopefully enable them to be another venue. The goal for this building was [to be] a vibrant community building that plugs into the community and the events that are going on in the community.”
Changing technology will no doubt play a large role in that, so the structure has been designed to handle new communication system requirements. The designers incorporated a raised floor system with 6 in. of open space beneath that can be easily accessed for new cable configurations.
The library will start out with a large portion of the floor plan dedicated to shelving and book display. But experts predict that that floor space requirement will continue to decline, Raike notes. As a result, large open spaces and detachable partitions are prevalent in the design.
The “library of the future,” as it is being called, will feature a
dramatic, six-story atrium that will flood natural daylight into the
structure. © LAKE|FLATO, MOKA Studio
The new central library will also embrace technology by providing access to it to those in the community who would otherwise be unable to afford it. Bridging this “digital divide” was a key aspect in the design, Raike says.
Site preparation is nearly complete for the building, which will include two belowground parking levels. The geotechnical conditions at the site have presented the team with a formidable engineering challenge Raike says.
“It’s been an interesting project in that regard,” Raike says. “When we got the geotechnical report back, the strata we were building on was not very good.”
The engineering of the foundation is being conducted by the Austin firm P.E. Structural Consultants, Inc. In written responses to questions posed by Civil Engineering online, Joelle S. Rosentswieg, P.E., a project manager and senior structural engineer for the firm, said, “We had several concerns regarding the site’s subgrade properties. This site is bordered by flowing water on two sides—Lady Bird Lake and Shoal Creek. As a result, we had a high water table to contend with. In addition, the subgrade soils consist of poor-quality sand layers for 70 to 75 ft below grade. Hard limestone isn’t encountered until depths exceeding 100 ft.”
These poor soil conditions were exacerbated by a vast array of infrastructure beneath the site. Some of it, such as a wastewater conveyance tunnel, was constructed recently. Others, including 60 in. diameter cooling pipes for the defunct power plant, are artifacts of the area’s industrial past.
“We knew most of that stuff was there because we had ‘as-builts,’ but there were some surprises,” Raike says.
“Because the library will contain two levels of parking below ground level, water infiltration, large hydrostatic water pressures, poor subgrade materials, and the below-grade tunnel were all driving factors for selection of the foundation system,” Rosentswieg said.
The team initially considered a drilled pier foundation for the site, but rejected that because the piers would have needed to be exceptionally long to reach bearing material and would pierce any waterproofing membrane that protects the building envelope.
“It became pretty clear that a pier system was going to impact the tunnel and cause all kinds of headaches,” Raike says. Instead, the team went with a massive mat foundation—approximately 200 ft by 200 ft by 6 ft thick. Atop that, the structural system will be constructed of concrete until the sixth floor, at which point is will switch to steel to facilitate open floor plans.
“Mat slab foundations, while unusual in the Austin area, are common in areas with wet and/or weak soils, as they help create a continuous watertight building envelope, and the thick mat distributes concentrated column loads across a large area so weaker soils can effectively support the building,” Rosentswieg said.
“A mat slab foundation also provides a heavy building base, which helps to counteract the large water uplift pressures from the high water table acting on the underside of the building,” Rosentswieg added. “Finally, a mat slab solution lessens potential exposure to contaminated soils prevalent at the site and eliminates any conflict with the tunnel below.”
Terracon Consultants, Inc., of Olathe, Kansas, provided geotechnical engineering on the project. Hensel-Phelps, of Greeley, Colorado, is serving as the construction manager-at-risk. Urban Design Group, of Austin, provided civil engineering. And Datum Engineers, Inc., also of Austin, provided structural engineering for the aboveground portions of the building.
The project includes numerous sustainability strategies. Rainwater- and condensate-collection systems will pool more than 1 million gal. of water each year, which comfortably exceeds the facility’s nonpotable water demands.
The library will also feature a 200kW photovoltaic array. That coupled with energy-saving measures and natural daylighting will mean that the facility will operates at 30 percent greater efficiency than local codes require.
The construction team is nearly ready to place the mat foundation, which will be accomplished during a weekend because of the large amounts of concrete required to be delivered to the site. The entire project is slated to be complete in spring 2016.