Two Places, One Look

Masonry Makes for Cool Parking and Chilling Facilities in Austin

By Rob Patterson

Brick is helping bring beauty to two adjacent structures in downtown Austin-the five-level, 200,000-sq.-ft. Convention Center Parking Garage and the three-level, 80,000-sq.-ft. Austin Energy District Cooling Plant.

The buildings, both utilitarian in nature, differ in their basic construction and serve two different city entities, the Austin Convention and Visitors Bureau and the city-owned utility.

"We wanted them to have their own identity, yet be compatible with each other and contribute to the downtown environment," said Carl Gromatsky, a partner in Austin-based Barnes Gromatsky Kosarek Architects, who designed the project in partnership with structural engineers Jaster-Quntanilla & Associates of Austin and MEP engineers Goetting & Associates of San Antonio. "Thus the same brick, concrete and metal screens are used all the way around."

Work began on the nearly $30 million project in December 2003. The $10.5 million parking garage opened in February, and the $19.25 million cooling plant will be completed in August. The two structures are separated by a 2-in. expansion joint.

The garage is poured concrete with post-tension cable, while the plant building, which includes a 23-ft.-deep sublevel, is cast-in-place pan slab.

A total of 18,000 cu. yds. of concrete was poured for the project.

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Downtown traffic posed a problem for the larger concrete pours. "For anything that was 300 cu. yds. and up, we'd start at midnight and pour all night," said Joey George, one of two project supervisors for general contractor SpawGlass of Austin.

Acme Santa Fe blend brick faces the majority of the two pedestrian entry towers at the north and south corners of the west end of the garage. Concrete block and stainless steel screen panels cover the rest of the structure.

"The façade is broken up with concrete and the stainless steel panels to help scale the building down," Gromatsky said. "If it were all brick it would have a different feeling and be more monolithic than it is."

Curved glass panels are mounted on the exterior of the towers from levels two to five. "We assembled the structural steel frame and panels on the roof and then hoisted them down into place," George said.

The garage also includes 30,000 sq. ft. of retail space at the ground level with cedar panel awnings on the exterior.

Before work could begin on the garage, 20,000 cu. yds. of material needed to be excavated from the east end of the site for the plant. A tunnel for the chilled water from the plant had to be built under the garage to tie in with the city's existing chilled water lines.

The framework of the plant is engineered to carry high stress loads and vibrations. To carry the load of the chillers on the ground level and cooling towers on top of the building, concrete beams up to 5 ft. thick loaded with redundant rebar were cast into the slabs.

One 192,000-lb. chiller is initially being installed on the plant's first floor with room for five more; three cooling towers will be placed on the roof with room for 11 more. The sublevel, a pump room, is also designed for future expansion.

On the northeast corner of the site is a 4,800-sq.-ft., 1.5-billion-gallon water tank with three closed-loop systems inside for the glycol chiller, condenser and chilled water. Its concrete walls are 5 ft. thick at the bottom and narrow to 3 ft. thick at 12 ft. high and above. "It's a huge mechanical job," George said.

To beautify the tank's exterior walls in a fitting fashion that expresses its function, it will be faced with a "metaphorical ice cube" mosaic of 8-in. colored tiles adhered to the concrete as part of Austin's Art in Public Places program. "We wrestled for a long time with what that tank should be, and I think all of us felt at some level that it should reflect what it contains," Gromatsky said.

The remainder of the building is faced with brick and glass window wall. "On the plant side we worked to modulate the façade to be scaled more like a downtown building should be and break it up with glass," Gromatsky added. The steel screens will overlay the upper level exterior in a continuous serpentine pattern that will help hide the cooling towers.

The relationship of the schedules for constructing the two buildings-with the garage slated to be completed in about a year-presented complications.

"The garage had to be open sooner than the plant, and yet we couldn't start the garage until we did the excavation and basement level for the plant, Gromatsky said. "So there were some scheduling issues."

The downtown site also had a highly constricted laydown area. "We had no room whatsoever, 25 to 30 ft. at one end and that was it," George said.

The tight site impacted Rudd & Adams Masonry of Boerne in its goal of laying 200,000 bricks and 80,000 concrete panels. "It's hard to get material around to the different areas," said company president Terry Adams. "We stacked a lot of activities due to the time constraints and had our deliveries at 4 or 5 a.m.

"It was a tough job, but we knew it was tough going into it. But we get a kick out of hard projects."

The rainy weather also daunted the masonry work. "If the mortar gets wet it streaks down the brick, which just soaks it up like a sponge," George said. "That really set us back."

George also praised Rudd & Adams for its attention to safety. "Their scaffolding is immaculate," he added. "The ladders are lashed tight, and their scaffolds are fully decked with toe boards on them."