Phoenix Library
by K. Robert Wendel

The city of Phoenix is embracing green building at its new $2.6 million Desert Broom Library.

The 15,000-sq.-ft. high-design project follows numerous Leadership in Environmental Engineering and Design requirements, including the use of recycled lumber, wood certified by the Forest Stewardship Council and on site recycling of trash and materials.

"The city is really trying to be pro-active in the green build arena," said project manager Art Jordon of Phoenix-based Linthicum Constructors Inc. "Phoenix is trying to be on the leading edge of energy efficiency."

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Built on an isolated foundation, the new library sits under a giant floating roof that not only encloses the library but also provides shade for a 10,000-sq.-ft. outdoor reading patio.

Fifty randomly placed steel columns support recycled wood beams, which are capped off with a built-up roof system. The steel columns are naturally rusted and covered with a clear coat, eliminating the need for paint and lowering volatile organic compounds.
The columns sit on 55 caissons 2- ft. in diameter. and drilled 6- ft down.

"The building acts like a nurse tree, with other trees growing up in the shadows," said project architect Steve Kennedy of Phoenix's Richard and Bauer. "The columns represent randomly spaced trees to give a natural look, like trees coming from out of the desert."

Linthicum Constructors started work on the construction-manager-at risk project in November. The anticipated opening date is in October.

The project sits on a master- planned 35-acre parcel at Tatum and Cave Creek roads that was mostly virgin desert. A 96-space parking lot and a city park are also planned for the site.

Designers and contractors want to preserve as much of the natural vegetation as possible. Site fences are just a few feet from the building perimeter, so workers don't disturb the desert.

"For the most part, we are trying to blend in with the existing desert," said civil engineer Mike Jackson of Phoenix-based KPFF Consulting Engineers. "The architect wanted to maintain the rural feeling so the building wasn't sticking out of the desert."

On the library's side facing Tatum Boulevard, a plywood sheer wall gives the mostly glass building sheer strength. There also are limited runs of masonry walls. The plywood sheathing will be covered with translucent "polygal" panels.

The other three sides utilize glass curtain walls to provide daylighting and limit the use of electric lights. The project has a complicated electrical system, with all the space in the elevated floor system required for data wiring.

"We couldn't run anything in the elevated floor space and most of the ceiling was open, so we ended up stubbing 300 to 400 penetrations from underneath the slab," said Ted Wilber, a project manager for Scottsdale-based JEN Electric. "The city librarian felt he needed as much room as possible for data (cables) down the road, so we had to keep everything under the slab."

Much of the library's lighting comes from glass curtain walls and skylight cut outs in the roof. The three skylights feature large translucent cubes that descend from the ceiling. Plans call for using the cubes as projectors to view various images and media. "There are very few walls, but the L-shaped masonry walls are the shear walls that hold up in case of an earthquake," said structural engineer Richard Smith of Phoenix-based KPFF Consulting Engineers. "We used drag straps (long beams with tie straps) to transfer the load from the main roof around the skylights and anchored them to the masonry walls."

Both the mechanical and electrical systems were designed under L.E.E.D. guidelines. The library features high-efficiency roof-top package units, which combined with the building's natural shading, should help out on electric bills.

The building doesn't use much ductwork, which cuts down on fan electrical load and reduces the friction load required to push air through the ducts.

"We are trying to make a building that is very efficient from not only an energy standpoint, but also from a renewable resource standpoint, but still make it usable for an owner on a tight budget," said Monte Sturdevant, president of Energy Systems Design Inc. of Phoenix.

Concrete with a 25 percent composition of fly ash was another L.E.E.D. component used in project construction. Crews from Glendale, Ariz., based JEC Contracting Corp. poured more than 400 cu. yds. of varying colors and shades of concrete.

"There's quite a variety of concrete," said Jerry Everett, a project administrator for JEC.
"It's a very unique project with a lot of exposed aggregate, ground concrete and colored concrete."

This isn't the only "green" library Phoenix is building. The city recently tapped Tucson-based Line and Space Architects, along with Linthicum Constructors, for the new, 25,000-sq.-ft. Caesar Chavez Library in south Phoenix.

"We are looking at green building on a project-by-project basis," said city architect Jon Kolstad. "Our main concentration is in air conditioning and heating, so we are putting the most efficient systems we can possibly buy into our building and looking at the long-term payback."

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