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ASU Polytechnic Green
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Dromiack notes that the project budget was modest, so it was imperative to use low-cost, yet sustainable, materials in the design. "We decided to make very simple concrete masonry unit buildings," he says, "then added to the exterior perforated and weathered metal screens, which served the purpose of shading the building from direct solar gain, as well as reducing glare for occupants looking out their windows."
The screens also became a primary unifying visual element for the complex.
Substantial glazing provides daylighting and views; an estimated 81 percent of regularly occupied spaces are daylit. In response to extreme summer sun exposure, the buildings employ horizontal shade devices on their south facades and vertical shades on their east, west, and north sides. The structural system is an exposed steel frame expressed throughout the buildings.
Linked Matrix
ASU wanted to foster an environment of interdisciplinary contact, a place where students could come together and discuss ideas. "One of the key elements to our design was to use shaded linkages, portals, and atriums to create a building complex that offered easy and comfortable pedestrian movement and increased opportunity for interaction and collaboration," explains Dromiack.
These shaded walkways and courtyards connect the three main structures and two smaller structures visually and physically, making them into an integrated unit. Maximizing external circulation and reducing enclosed circulation takes advantage of the climate and helps reduce the energy use and associated costs necessary for thermal management.
The buildings are designed around three-story atriums that are fully covered by perforated metal panels on the horizontal surfaces and open on the vertical surfaces for ventilation. Each atrium has three large fans for increased air circulation, and the north and south ends are open to create view corridors and increase air movement.
These layers also provide a comfortable transition between indoors and out. "When you come in from the high sun glare through shaded courtyards and pedestrian ways into a shaded atrium, your eyes have a chance to gradually adjust to the lower light levels in classroom environment," Dromiack says. "When you come out of the classroom environment, your eyes can gradually adjust to the brighter light."
Harnessing the Desert Sun
Each building maintains a unique identity while still remaining tied to the central theme. The tower at the entrance to Santan Hall is distinguished by a big, white Teflon-coated fabric panel on the side. Peralta Hall's entry tower bears a lattice of Trex composite lumber, which is very durable in the western sun and won't warp or split. The tower of Santa Catalina Hall is draped in weathered perforated metal. Each tower has an observation point like the bow of a ship, affording students a view across the entire campus.
In the early phases, it was decided that the buildings should be designed to support future photovolatic (PV) installments. In all three main buildings, the atrium spaces have a sawtoothed roof configuration that can incorporate PV panels.
Otherwise, sun is reflected away from the building roofs by bright white EPDM (ethylene propylene diene M-class) rubber membrane to reduce solar gain. Having about 80 percent of roof surfaces covered by this reflective material reduces the heat island effect.
The Santan Hall team room is already solar-powered via building-integrated PV modules that were donated through ASU's Photovoltaics Testing Lab. The panels cover the tower's observatory roof, with the solar cell components readily visible to students.
Greening a Brownfield
The ASU Polytechnic campus stands on a former U.S. Air Force base, and the brownfield site presented some challenges. Vapor extraction, monitoring, and vapor barriers were necessary on the west end of the project site.
Existing surface stormwater drainage posed a significant problem. A thousand feet (300 meters) of roadway were removed and replaced with a desert-landscaped mall that captures stormwater in small basins throughout.
The hardscape is a combination of exposed aggregate concrete and stabilized decomposed granite which, in conjunction with the landscape, also reduce the heat island effect. There is no asphalt paving in the project, which also includes 3,500 tons (3,200 metric tons) of recycled concrete and asphalt as underlayment for walkways and one road.
Open vegetated spaces cover an area over three times the footprint of buildings. These open spaces have been restored with native and adaptive plants as part of a landscape design that helps reduce potable water use by half. Low-flow kitchen sinks, and waterless urinals, and low-flow and dual-flush toilets further contribute to water conservation.
The project team for the new ASU Polytechnic academic complex successfully surmounted a slim budget to create cohesive, sustainable buildings, quietly attuned with their surrounding landscape.
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Susan Smith is the editor of AECCafe, an online news portal for the architecture, engineering, and construction industry, as well as GISCafe and GISWeekly, an online portal and weekly magazine for the geographic information systems industry. She has been writing about architecture and technology for over 15 years and resides in Santa Fe, New Mexico. More by Susan Smith
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