Photos: Gate Precast Co.

“We loved the composition of the materials and the counterpoint between the precast and the wood and glass.”

Bob Powers

 

Best Custom Solution

Cityplace Uptown Station

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To improve the speed of turnaround for unidirectional trolleys and allow for future one-sided ones, designers created a unique trolley turn at the intersection of two key city streets in Dallas, Tex. The structure became an area landmark with its almost whimsical combination of precast concrete structure, glass, and wood.

Precast concrete was chosen for the structural supports due to its integral natural beauty, plasticity, durability, and structural efficiency. The columns taper in two directions, which would have been difficult to achieve with other materials. The repetitive nature of the components also played to precast concrete’s strengths.

“This was one of the favorite projects of the jury,” says Bob Powers, a member of the buildings awards jury. “We loved the composition of the materials and the counterpoint between the precast and the wood and glass. This project is a great example of how you can integrate precast with other materials. The precast forms are very strong and powerful as a supporting structure and serve as a great counterpoint to the light and delicate nature of the glass and wood canopy.”

The precast concrete columns are freestanding, with all other elements tying into them. Producing the high quality needed for the columns, which can be approached on all four sides by the public, required a special casting process. Four-foot (1.2‑m) vertical forms were created, into which was poured a flowing concrete mixture that minimized entrapped air. The mixture had to flow around a variety of obstacles in the form, including canopy tubes, conduit, pipes, and reinforcement.

Only 12 pieces were required, and they were given a medium- to heavy acid-etched finish to promote both strength and aesthetics.

Each column, about 3 × 30 ft (0.9 × 9 m) and weighing 24,000 lb (11 tonnes), was designed to lean out of plumb away from the center by 14 degrees, creating erection challenges. A hollow steel bracket was fabricated and bolted to each footing to keep the columns from pulling away from their designated position at the base while maintaining their angle.

The columns then were lowered into the bracket and welded in alternating sequences to avoid excessive heat on the concrete. Erection of the pieces took just under one month to complete.

“The judges were excited to see this nice urban solution,” says Debra Kunce, a member of the buildings awards jury. “The trolley station is very light and airy. It has a nice mixture of precast concrete–based stability and airiness from the other materials. The precast columns just soar through other materials. This offers a new way for designers to think about precast and for those on the street to see precast.”

Location: Dallas, Tex.
Owner: Cityplace, Dallas, Tex.
Architect: Good Fulton and Farrell, Dallas, Tex., www.gff.com
Engineer: Brockette Davis Drake Inc, Dallas, Tex.
Contractor: EMJ Corp. Irving, Tex.
Precaster: Gate Precast Co., Hillsboro, Tex., www.gateprecast.com
Project size: 30,000 ft2 (2,800 m2)
Project cost: $3 million