Best Parking Structure, Co-winner - MacArthur Center Decks, Norfolk, Va.
Precast Helps Uptown Come to Downtown
The city of Norfolk, Va., didn't want the two parking decks for its huge, soon-to-be-built retail mall, MacArthur Center, to look like a garage. They also wanted to ensure the structures complemented this redeveloping area's rich history replete with colonial buildings, museums and memorial statues. To achieve that, the designers made full use of precast concrete's plasticity to create structures that fit in well with their neighbors.
"We had an extraordinary process of meeting with the local design review committee to make sure the decks had an expressive exterior," says Jarrell DeBrohun, project architect at the center's owner Taubman Realty Group, who served as vice president at Hobbs & Black Associates in Ann Arbor, Mich., the architect of record for the construction. "Unlike most parking structures, the idea here wasn't to hide them but to give them an old Williamsburg-esque look."
Details Add Interest
An Exterior Insulation Finish System was considered, he adds, but precast was more durable given the area's potential for hurricanes, says Ken Perkins, project architect at Hobbs & Black. A significant challenge came from the owner's request that all conduit for perimeter lighting and in the elevator shafts had to be embedded in the precast components to provide a clean look. This took careful coordination and casting to provide the appropriate pieces.
The South facility's geometry was complex and monumental. At the building's top, the cornice profile was designed to be architectural but had to be constructed as a structural component since it features 60-foot spans, which are not standard for architectural concrete. "About a quarter of the architectural precast is load-bearing," says Andrew Wise, project manager at the structural precaster, Tindall Corp. in Petersburg, Va.
The three-story mall is the same height as the five-story parking structure, which meant some floors did not match up for smooth flow at each level. Floors 1 and 2 of the parking structure merge with the adjacent mall directly, while Level 3 is slightly lower and Level 4 is slightly higher than the third floor of the mall.
"So many architectural elements had to match up," says Al Freeman, president of Seaboard Services of Virginia in Richmond, Va. "It was an intense engineering and coordination effort." His team used 3-D CAD analysis to determine how to piece together the project with its cornices, folded shapes, shapes with relief and returns around corners. "We called it build-design by the time we finished," Freeman says. "The connector towers were projects within themselves."
The towers, called beacons, connect the street, the parking decks and the mall. Their design is in keeping with the Monticello look, incorporating local red brick over structural precast. To draw visitors into the mall, the stair connectors were designed as ornate accents with tree columns with arms that branch off into curved landings.
North Offers Different Look
The two structures' precast double tees were designed to span 55- by 36-foot bays. Lateral support came from shearwalls, structural steel tube diagonal bracing and columns. The decks each had five levels with a total of 4,600 parking spaces. The footprint for the north deck is 402 by 168 feet with 1,553 structural precast pieces and 203 architectural ones; the south deck measures 268 by 772 feet, with 2,838 structural pieces and 264 architectural ones.The tops of the double tees were broom-finished during production for safety and aesthetics and required no topping. They were cast monolithically with a lift edge for water drainage and have a minimum mix strength of 6,500 psi. Sleeves cast in the tees and inserted in the bottom edge accommodate and hide the conduit for the lighting and security systems for the parking decks.
"The biggest plus of precast is that it offers a clean, aesthetically pleasing look and that it allows a fast schedule," Bhandari says. "The production and erection being independent of each other allowed for better quality control."
The precast components for the North structure were erected in six months, while the South structure took nine months. A high per-diem penalty clause made the schedule imperative, Freeman says.The mall, located directly across from the memorial to General Douglas MacArthur, with more than 1 million square feet of retail and restaurant space, opened March 1999 - right on schedule. - Chris Santilli
The Judges Said...
As seen in ASCENT magazine