Taking the LEED

Tempe Goes for the Green on New Transportation Center

By Scott Blair

The city of Tempe's transportation department is looking beyond encouraging bus and bicycle commuting to find new sustainable solutions.

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In June 2006, the city began construction on a new 40,000-sq-ft transportation center that it hopes will be LEED gold certified upon completion in February.

"The project started out as just a 5,000-sq-ft building to house a ticket store and restrooms for bus drivers," says Bonnie Richardson, AIA, LEED AP, the principal planner and an architect with Tempe's transportation division. "In looking and talking about it, we decided an urban plaza was needed to integrate everything within the downtown while also being the heart of our transportation system."

The result was a three-story structure at the base of "A" Mountain that will house the transportation department, private offices for lease and retail shops.

The site also contains a central bus plaza with 13 bays for neighborhood bus routes and the FLASH bus that serves Arizona State University and downtown Tempe.

Phoenix-based general contractor Adolfson & Peterson Construction is building the masonry and steel-framed structure under a $24.5 million, construction manager-at-risk contract.

The site will also abut a major station for the Valley Metro Light Rail system, which should be operational December 2008.. The project will feature the state's first bike station, which was developed in California and is essentially a secure, indoor valet parking for bicycles, Richardson says.

The station will feature a double-decker storage system for bikes and a repair shop.

Another way the city is encouraging alternative modes of transportation lies in what the project doesn't have. "There is no parking, which is pretty unique," says John Kane, AIA LEED AP, design principal with Tempe-based Architekton, who co-designed the project with Portland, Ore.-based Otak Inc. "It's a truly multimodal building, with everything but the car."

There were some early snags at the site when, in accordance with state legislation for all new construction, archeologists investigated the site for ancient remains.

"It seemed like everywhere they put a shovel in they found something,"
Richardson says. "What we started out thinking would be a six- to eight-week archeological investigation turned out over nine months. The city was committed to making sure we did it right."

Significant finds included ancient structure walls, floors and hearths that are estimated to have been occupied from A.D. 500 to 1450.

Contractors were able to minimize delays by working around the digs and focusing on a portion of the site that had already been excavated.

The city's police department, located just to the west of the site, had a below-grade sally port used to transport prisoners in and out of the jail where the new building was going. Crews realigned the driveway and turned the sally port, which was below-grade to begin with, into a basement for the new structure.

The project features a variety of sustainable building techniques. One of the most prominent is the first green roof using native plants to be attempted in the Sonoran Desert climate, according to Richardson.

"The green roof will have lush desert planting because you want the dirt to be shaded as much as possible," says John Tomasson, project manager for Adolfson & Peterson. "Otherwise it would absorb the heat and hold it in."

After extensive testing of various green-roof options with the help of Arizona State University, Phoenix-based landscape designer A Dye Design chose to plant drought-tolerant native species such as bear grass and Rocky Point ice plant. "The goal is that they will be self-sufficient without watering once they are mature," Richardson says.

A 15,000-gal rainwater recovery system will provide water for drip irrigation and for power-washing public plaza areas.

A separate grey-water system will recycle water from showers, sinks and drinking fountains to refill toilet basins.





The building will utilize a high-efficiency central plant mechanical system that will have an under-floor duct system with individual controls. Coupled with the lack of interior partitions, the ducts provide future flexibility for reconfiguration of the office and leased spaces.



"For the size of the building, our drywall quantities are extremely low because of all the open space," Tomasson says.

The building's core area, including restrooms, elevators and stairwells, was purposely situated along the entire length of the west-facing exterior wall. "This helps create a buffer to the air-conditioned spaces and delays thermal transmission," Kane says.

Designers utilized 'U'-shaped, self-shading masonry block units to reduce solar gain.

Since the east face of the building will primarily be skinned in glass, heat gain there will be mitigated by a metal panel shade system suspended 10 ft away from the building.

"Occupants can adjust the panels, creating this active façade so that the building will always look different," Kane says.

Upon completion, the project will serve as a prominent educational tool to promote sustainable concepts. A monitoring system will provide the public with real-time data on the building's power and water usage.

City planners hope this and two other LEED-registered projects currently under way will help foster private green development in Tempe. "We are hoping this sets the standard so that we develop policy in a positive way," Richardson says.

Key Players

Owner: City of Tempe

Architects: OTAK; Architekton

General Contractor: Adolfson & Peterson Construction

LEED Consultant: Natural Logic Inc.

Subcontractors: DP Electric; Midstate Mechanical; Pete King Construction Co.; Red River Contracting; Roma Masonry; W & W Architectural Metals; Sunwest Landscape

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