Topsy-Turvy Tower

Skewed corners give Hearst Tower a distinctive image without upstaging a taller corporate neighbor in downtown Charlotte's banking mecca
August 11, 2010

Five years ago, Bank of America, the mammoth financial services company — it now has 4,400 banking centers in 21 states and the District of Columbia and 132,796 employees operating in more than 150 countries — decided it needed more space in its headquarters city of Charlotte, N.C.

The bank wanted an office building that would be eye-catching in and of itself, without detracting from its adjacent 60-story corporate center, designed by Cesar Pelli. This overarching requirement shaped the unusual design of the 47-story Hearst Tower, now the second tallest building in Charlotte, and led to the creation of a structure that looks as if it should be planted in the sky rather than in the ground.

Much of Charlotte's skyline was constructed from the 1970s through the early 1990s to accommodate the growth of Bank of America (then known as NationsBank) and First Union Corp. First Union (now Wachovia Corp.) built a 32-story tower in 1971. Bank of America followed with a 40-story headquarters in 1974. First Union topped that in 1988 with a 42-story building. NationsBank opened its Pelli-designed corporate center, the city's tallest building, in 1992.

The development of Hearst Tower coincided with the bank's rapid growth in the 1990s, marked by its merger with San Francisco-based BankAmerica in 1998. This event signaled the need for a second major structure for the new Bank of America.

Cutting corners

An immediately apparent feature of Hearst Tower is its four cantilevered corners, which project outward an additional five inches at each higher floor. At the base of the tower, the cantilevers are 14 1/2 feet long, while at the top, they are 28 1/2 feet. The corners at the 43rd floor are 14 feet longer than those at the 16th floor. These corner areas, typically used for executive offices, feature extensive glazing.

The rationale for the unusual corner geometry was that the outward spreading of the building's visual lines would complement, rather than compete with, the Pelli-designed corporate center. Hearst Tower's expanding profile is the inverse of the corporate center's more conventional wedding-cake massing. The buildings thus serve as counterpoints to each other, according to Charles Hull, design principal with the building's architect, Smallwood, Reynolds, Stewart, Stewart & Associates, of Atlanta.

Hearst Tower was also designed to be compatible with the IJL Financial Center across the street, a 30-story office building also developed by the bank and completed in 1997. The staggered placement of the three adjacent buildings permits unobstructed views of each one.

The design of Hearst Tower's base, which houses a variety of functions, was a challenging assignment, according to Hull. The base contains the building lobby, 42,000 sq. ft. of retail space, and parking for 1,500 cars. It is topped by three levels that contain Bank of America's trading operations — a surprise addition to the project.

Retail space is provided on three levels, in order to serve lobby entrances on two levels and on a third level that has a street-spanning pedestrian bridge that connects Hearst Tower to the headquarters building. One design objective was to maximize the number of retail storefronts facing the sidewalk, something the corporate center lacks.

A 10-ft. difference in elevation between bordering streets to the east and the west necessitated the split-lobby arrangement. The west lobby connects with Tryon Street, the city's main north-south artery, via an outdoor plaza. It was raised to provide a 16-ft. floor height for retail and service areas, as well as a more dramatic presence on the plaza. Seven full levels and three partial levels of parking also are provided on the building's lower floors.

To help accomplish the visual transition from what Hull describes as the "aircraft carrier base" to the tower, cladding with an Art Deco motif was used at the base, including intricately detailed precast concrete panels at the fourth level.

Melding concrete and steel

Hearst Tower's lower 14 floors are concrete-framed, while the tower utilizes a steel frame. The transition between systems involved the transfer of significant forces, according to Steve Hamvas, project manager with the project's structural engineer, Stanley D. Lindsey & Associates, Atlanta. The transfer was achieved by embedding steel members into the concrete on floors 14 and 15.

A number of W14x730 steel members, each weighing 730 lb. per lineal foot, were encased in the building's 70x70-ft. concrete core, which takes lateral loads. Because domestic mills were not rolling members larger than W14x398 at the time the steel order was placed, these large members had to be obtained from outside the U.S. This did not delay the project schedule, since the lower floors were of concrete construction.

As construction was emerging from the ground, the bank decided to have a little fun with the architects by asking them to incorporate a trading floor in Hearst Tower. Acquisitions and the consolidation of operations in Charlotte were straining the capacity of the existing trading floor, which once served a bank with total assets of $75 billion but was inadequate for a bank now exceeding $600 billion in assets.

The trading facility, designed by the New York office of Skidmore, Owings & Merrill, occupies three levels. One houses equipment. The 6,000-sq.-ft. trading floor is two stories high in the portion of the base that extends beyond the tower footprint and one story high beneath the tower. Approximately 1,000 trading desks will be located in this area when the trading facility is fully operational.

Mechanical/electrical engineering was provided by New York City-based Cosentini Associates. The general contractor was a joint venture of Charlotte-based Shalco and Atlanta-based Batson Cook.

Edward Barbieri, project director with Cosentini, says air-cooled chillers were specified to eliminate reliance on a water-cooled system that serves critical air-conditioning requirements. The trading facility has full emergency electrical-generation backup, as well as built-in redundancy for air conditioning.

The trading area is designed to enable the continuation of operations if public utilities are disrupted. An 88,000-gallon water reservoir provides a source of fresh water.

The addition of the trading floor required a major increase in the capacity of base building mechanical/electrical systems, says Tom Boudreaux, VP of engineering with the building's design/build mechanical contractor, MMC Group LLC, Metairie, La. The initial plan called for a central plant with two 800-ton chillers and a 300-ton chiller. The revised plan incorporates three 1,100-ton chillers and a 400-ton chiller, along with added cooling-tower capacity. Because the bank wanted the trading area to be supplied separately from base building system, it was necessary to install heat exchangers in the central plant. "We had to squeeze a lot of equipment into a space that already wasn't that big," Boudreaux says.

Changes to the building's exterior design were also needed to accommodate the trading facility. The major revision was the addition of a 50-ft. high mullionless glazed wall at one end of the trading floor. This glazing was installed with the aid of an intricate balancing system that involved the use of water-filled tanks placed on top of a truss. The amount of water was adjusted to provide the proper amount of deflection of the framing as the weight of the glazing increased with the placement of individual glass panels.

Hearst Tower utilized nearly 300,000 sq. ft. of precast concrete — 268 fin panels, 377 flat panels, 508 spandrels, and 1,134 window units. They were fabricated and installed by Metromont Prestress Co., Greenville, S.C., under an $8.7 million contract. The original plan was to use column covers and spandrel units, according to Brian Drummond, marketing manager with Metromont. However, by slightly changing the size of window openings, one-piece punched window units were ultimately used, significantly reducing the number of pieces required.

The bank occupies 40% of Hearst Tower, in part because the Federal government requires banks to occupy a substantial portion of buildings that they develop, according to Bank of America SVP John Saclarides. Signature tenant Hearst Corporation leases 200,000 sq. ft., while a law firm occupies the top seven floors. A typical office floor plate in the building is 22,000 sq. ft.

Hard and soft costs for Hearst Tower's construction, excluding the trading floor, totaled about $185/sq. ft., according to Saclarides. Hearst Tower was completed and occupied last fall.

A touch of Deco

Art Deco exterior features include the building's six-story crown, which is reminiscent of the Chrysler Building in New York. The crown consists of triangular windows and outward-thrusting metal ribs. Early design schemes envisioned the crown in the shape of a vase.

Art Deco touches are brought into the interior. For example, sunburst designs are incorporated into the ceiling of two lobby areas. Elevator lobbies are paved with black and white Chinese marble. Incorporated into the design of lobby railings are 1920s-era bronze grilles cast by the noted French Art Deco artist Edgar Brandt. They were salvaged from the Au Bon Marché department store in Paris.

Today, Bank of America controls about 6 million sq. ft. of office space in downtown Charlotte, of which it owns 4.5 million sq. ft. In keeping with former CEO Hugh McColl's philosophy of promoting the urban core, none of the bank's major development has occurred in the suburbs. The bank's investment in downtown Charlotte during the past decade totals approximately $2 billion.

With Bank of America ranked third and Wachovia ranked fifth in total assets among U.S. bank holding companies, Charlotte has become one of the country's major banking centers. The banks' extensive development activity within the compact downtown area has brought to Charlotte in a matter of years changes that ordinarily would take decades.

         
 

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