Long before the terrorist attacks of Sept. 11 erased the landmark twin towers of the World Trade Center from the New York skyline, the concept of the super-tall building was passing into architectural history — at least in the United States.

Soaring, 1,000-foot plus towers are still rising in places such as Malaysia and Hong Kong as literal symbols of economic ambition, but no such projects are on the drawing boards in the U.S. Even when Silverstein Properties starts rebuilding at the World Trade Center site, it is most likely that a cluster of more modest skyscrapers will take shape.

The tragic events of Sept. 11 only confirmed what architects knew about super-tall buildings. “America's fascination with constructing a building 110 stories tall is over,” says T. J. Gottesdiener, managing partner at Skidmore, Owings & Merrill in New York.

Virtually every type of building design — from multifamily to mixed use to retail and office — is being reassessed as architects and clients focus on ways to heighten security. The challenge is to strike a balance between appealing architectural design and safety measures that avoid turning buildings into fortresses.

“We're still assessing the impact of Sept. 11 on every aspect of architecture,” says Tony Belluschi, principal and director of commercial mixed-use projects for OWP/P Belluschi Architects in Chicago.

Structures that are in the early stages of construction or on the drawing board may undergo subtle readjustments to ensure the safety of tenants. Several significant projects that were conceived prior to Sept. 11 will come to fruition in the next year or two, including the New York Times Building and the AOL Time Warner Center in Manhattan. These projects represent the trends firing the architectural engine of the early 21st century.

The skyscraper continues to propagate in urban areas, where the skyline is connected to the vibrancy and the image of the city. “I don't think Sept. 11 has affected the notion of a high-rise, not at the 40- to 60-story level. It makes sense in urban areas,” Gottesdiener says.

Today's newly built offices are modest in size largely because of cost control. “A super-tall building of 110 stories is much more expensive to build than two 50-story towers,” says Eugene Kohn, president of Kohn Pederson Fox Associates, an architectural firm in New York.

The terrorist attacks of Sept. 11 have made some architects question the value of tall buildings in suburban areas where land is plentiful, says Gary Fowler, principal at Thompson, Ventulett, Stainback (TVS) Architects in Atlanta.

“The tall building has clearly been an expression of man's ego, the pounding on his chest,” Fowler says. “It doesn't make sense except in places like New York.”

One indication that the appetite for super-tall buildings isn't going to make a comeback anytime soon is New York real estate mogul Donald Trump's decision to scale back his proposed Chicago tower at 401 N. Wabash on the Chicago River. The original plan to construct the world's tallest building has been replaced with a more modest, but still ambitious, proposal for a 78-story structure.

The building is being designed for Trump and Hollinger International, the publisher of the Chicago Sun-Times, by the Chicago office of Skidmore, Owings & Merrill. The tower would rise 1,073 feet and include 2.3 million sq. ft. of space, including up to 1.6 million sq. ft. of office space and 500 residential units. Construction is expected to start in 2003. Although he hasn't secured financing for the project, Trump's vast resources and connections to the banking world give the project more than just a fighting chance.

A symbol of the city

To be certain, New York isn't planning to relinquish its status as the skyscraper capital of the world anytime soon. Plans for new office towers are marching forward. One major project on the drawing board for the city is a 52-story tower in Times Square.

This office tower (pictured on the cover) will house The New York Times, and is a joint venture of the New York Times Co. and Cleveland-based Forest City Ratner Cos. Forest City is the project developer and ING Real Estate will participate as the financial partner. Forest City plans to break ground on the building in 2003.

In late December, architect Renzo Piano unveiled detailed architectural plans for the New York Times Building, which will be located on Eighth Avenue between 40th and 41st streets. The building will feature a striking glass curtain exterior that reveals the structural innards of the tower. New York-based Fox & Fowle Architects collaborated with Piano on the design of the building.

“Architecture tells a story, and the story this new building for the New York Times proposes is one of lightness and transparency, not defiance,” Piano says. “Towers are often symbols of arrogance and power, but this will not be our case. While building a tower fulfills the greatest challenge in the upward reach, it also contributes a presence on the skyline that is both vibrant and changing with the winds.”

Ceramic tubes that will reflect the color of the sky will enable the building's exterior to change colors, giving the impression of a building in motion.

Piano designed the tower to speak to the street. As workers and visitors circulate on the building's stairways, their movements will be visible from the outside. Piano considers this openness appropriate for the New York Times' headquarters, “as it is from the street itself that the newspaper metaphorically gathers its inspiration.” On the ground level, Piano has created an internal garden that will be visible to pedestrians.

The New York Times Building also will feature a double-thermal-pane glass curtain wall, which will be screened by horizontal ceramic tubes placed on a steel framework and positioned one to two feet in front of the glass. The tubes reflect sunlight in the summer and absorb natural light in the winter, creating a higher degree of energy efficiency.

The building will measure 748 feet tall, but the ceramic screens will rise to 840 feet while a central mast will reach 1,142 feet. The ground floor of the 1.5 million sq. ft. building will contain retail stores and garden space, and the 52nd floor will feature a rooftop conference facility.

Another high-rise office building designed by Fox & Fowle, 3 Times Square, towers above Seventh Avenue and 42nd Street. Also known as the Reuters Building, the structure features a 60-foot high glass wall in the lobby and a series of 30-foot high video monitors that wrap around the corner of 43rd Street. The Reuters Building was completed in 2001.

Overseas: The taller, the better

Even though the super high-rise fad is over in the U.S., in Asia super-tall buildings are in vogue. The super-tall building is viewed as symbol of a country entering the 21st century, says Kohn of Kohn Pederson Fox Associates, a firm that does brisk business designing the super-tall buildings that are proliferating overseas.

Kohn and his firm are in the process of constructing one of the world's tallest buildings, the 460-meter (1,518 ft.) World Financial Center in Shanghai, which is scheduled to be completed in time for the 2008 Beijing Olympics. “The reasons for tall buildings are valid and still remain valid despite what happened on Sept. 11,” Kohn says.

Super-tall buildings allow developers to build in high-density areas, maximize land value and provide a place for people to gather for work and play, he explains. In cities such as Shanghai, with 15 million people crammed into 2,400 square miles, constructing super-tall buildings makes more sense, he says. “You can't deal with density unless you build vertically.” Super-tall buildings generally are more economically feasible in Asia than in the U.S. Foreign developers frequently put more personal equity into the deal to build high-rise structures and they face less capital constraints, Kohn explains.

When developing a concept for the World Financial Center in Shanghai, the architects wanted to find a way to express Chinese culture. In Chinese mythology, the square represents the Earth and the circle represents unity.

The open circle near the top of the building, some 50 meters in diameter, also will serve a more functional purpose — by allowing air to move through the open space to reduce the impact resulting from strong wind gusts. In Shanghai, wind is a force that must be factored into a building's design, Kohn says. Another feature that promises to give the World Financial Center in Shanghai a distinctive flair will be a Ferris Wheel encased in glass that rotates around the circle to allow views of the city. To entice visitors, retail shops and art galleries will be located on the top floors.

Safety first

As tall and super-tall towers are erected around the world, security and safety will have a major influence on the design of commercial structures. This doesn't mean that office buildings or landmark buildings will be designed to withstand the impact of a 767 commercial jet airplane loaded with fuel. If this type of airplane-secure fortress were built, it would probably be devoid of windows, or it would be underground, Gottesdiener says.

But there is little doubt that design safety will play a larger role going forward. “We will design buildings differently,” Gottesdiener says emphatically. The average person won't detect the small changes such as wider exit stairs, mechanical smoke inhalation devices and firefighter communication stations that will provide the “next evolution as opposed to a revolution in design.”

Dan Kaplan, a principal and director at Fox & Fowle Architects in New York, says that “blast resistance” is on the minds of clients, along with more standard security issues such as public access to lobbies. “Technology is going to ease the bunker feeling,” he explains.

Kaplan says that the most recent Fox & Fowle office building designs, including the Conde Nast publishing headquarters at 4 Times Square in New York, incorporate card reader systems that allow employees easy access and stop unknown persons from entering elevator banks. The flow of traffic is controlled, as visitors report to the front desk for building access.

Clients of RTKL Architects are asking for design features that address their specific security needs. “Sept. 11 has changed many of our clients' perspectives on what they want to build and how they want to build it,” says David Hudson, president of RTKL Architects in Baltimore, Md. “All of our clients have security on their minds now, and I don't think that will go away.”

Hudson says that any security design changes are likely to either be functional or operational. On the functional side, the trend might be to employ security methods to keep traffic in public spaces separate from residential spaces. On the operational side, buildings could be designed with one public entry and exit point to maximize security control. Also, loading/delivery docks could be separated from vital functions, he says.

Mixed-use maintains allure

One trend that was under way long before Sept. 11, and which will continue to evolve in the urban core, is mixed-use development. “There is a major trend to rebuild our cities, especially the inner cities,” says Hudson of RTKL. “The most active trend is downtown projects, which include residential, office buildings, retail and hotels.”

The driving factor of this trend is cultural change within communities, says Ronald Altoon of Altoon + Porter Architects in Los Angeles. “Mixed-use projects become lifestyle centers,” Altoon says. The younger generation wants a high quality of life, and it wants the workplace to be located near places to shop, dine and eat.

Transportation hubs in cities also are becoming much more than a train stop. Projects such as Mockingbird Station in Dallas, which was completed last May, offer commuters a place for shopping and recreation. RTKL designed the 10-acre transit mixed-use project, which is connected to the Mockingbird Lane light-rail commuter station.

The project includes 250,000 sq. ft. of office space, 211 loft-style apartments, a theater, and more than 90 shops and restaurants. The project combined both new and old buildings. To maintain the authentic feel of the downtown neighborhood, a 1930s brick warehouse was converted into loft-style apartments, with the lower level becoming retail shops.

“What we're seeing are these linkages of different usages and focuses,” says Doug Demers, principal at Perkins & Wills in Dallas, referring to transit systems with mixed-use offerings. “You're creating very exciting environments where people want to live, work and shop.”

The AOL Time Warner Center mixed-use complex under construction at Columbus Circle in Manhattan is an example of a property that expects to offer workers, residents and shoppers the best of all those worlds.

Estimated at a cost of $1.7 billion, the 2.1 million sq. ft. project to be completed in 2003 includes: the new AOL Time Warner headquarters; Jazz at Lincoln Center, a Jazz performance space; the Mandarin Oriental Hotel; 191 luxury condominiums known as One Central Park; and the Palladium, a retail space that will include retail, restaurant and entertainment tenants.

Several architectural firms have been hired to work on separate components of the massive AOL Time Warner mixed-use project to give it a varied feel. Skidmore, Owings & Merrill in New York serves as the master architect on the project. Elkus/Manfredi Architects is focusing on the Palladium retail component. Rafael Vinoly Architects is designing the Jazz at Lincoln Center section. Brennan, Beer and Gorman Architects is designing the Mandarin Hotel. HLW International is overseeing the design for the AOL Time Warner facilities, which will include a CNN newsroom. And Ismael Leyva Architects is designing the luxury condominium residences.

These types of mixed-use projects aren't just cropping up in the United States. The concept also is alive and well in Europe. One example is Salamanca Rail Station in Salamanca, Spain. Architect Grupo Riotisa asked RTKL Architects to participate in the design of the $6.6 million retail and entertainment venue.

The project wraps around the existing rail station. By using local stone on all the facades and creating a public square, Salamanca Rail Station is an integral part of the city. The project includes 53,000 sq. ft. of cinema space, 97,000 sq. ft. of retail space and restaurants and a 26,000 sq. ft. music court.

Retail needs to remain fresh

As potential terrorist targets, shopping centers face new security issues. Since the goal of shopping centers is to welcome customers, these public spaces are unlikely to be redesigned significantly to make them less accessible. At the same time, shopping center owners know that in order for a center to be profitable it must be safe. That's why owners of large regional centers spend hundreds of thousands of dollars annually on security measures, including retaining additional security guards and installing security and/or communication devices within individual stores.

For malls and shopping centers to remain a destination, the building has to reflect the values of the surrounding community, says Altoon of Altoon + Porter Architects. When retail buildings become stale and unattractive, customers will stop shopping there. For that reason, retail projects are often repositioned. This trend of turning old, tired spaces into shopping destinations has come about as some traditional “fortress” malls have lost their charm with visitors.

Redesigning a shopping center requires knowledge of local demographics, Altoon says. “First, you find out who the people are, their values and how they've evolved over time.” He says that it's important to make the redesign tie in as closely as possible to the interests of the residents who will be the center's future shoppers.

Focus groups help designers settle on a plan. “As you meet with groups, you put ideas on the table, and people will react to them,” Altoon says. “Then you make a judgment on what's going to work and proceed.”

Altoon + Porter is transforming The Shops at Tanforan, a shopping center in San Bruno, Calif., as part of a $105 million redevelopment for Wattson Breevast, a developer in Newport Beach, Calif.

This outdated, drab 965,000 sq. ft. center will be turned into a bright, airy mall of approximately 1.1 million sq. ft. Restaurants, a café and bookstore welcome visitors at the main entrance. Also, a new cinema complex will be added to attract visitors. Altoon + Porter incorporated images of the San Francisco Bay into the design, including a boat-shaped entrance to reflect the city's shipping and sailing heritage.

Rebuilding downtown Manhattan

Undoubtedly, architects will play a key role in helping shape any project and/or memorial that is to be built at the site of the former World Trade Center, now known as “Ground Zero.” The process will involve the cooperation of city officials, the federal government, the Port Authority of New York and New Jersey, and Silverstein Properties, the 99-year leaseholder of the towers.

The Lower Manhattan Redevelopment Corp., an 11-member agency organized to help rebuild the downtown area, will lead any redevelopment of the site. Several architects already have expressed their ideas on how the site should be rebuilt.

Any shifts in architectural design in the U.S. ultimately reflect the changing wants and needs of building occupants over time, according to Hudson of RTKL. As Ralph Erskine, a Swedish-British architect in London says, “The job of buildings is to improve human relations; architecture must ease them, not make them worse.”

Not your typical office space

A company that designs clothes for children needs a space that reflects that purpose, says Andrew Ling, a managing director of DEGW, the design firm that developed a concept for The Children's Place headquarters in Secaucus, N.J.

“We wanted to match the design of the space to how the organization does its work,” Ling says.

The Children's Place wanted a work environment in which employees could communicate freely. To make this exchange of ideas possible, Ling designed an open environment where employees could talk amid the cubicle spaces. There's also an area with bar stools where employees can sit and work together. He also added children's mannequins at work stations to allow employees to test their designs.

David Fournier, principal at Aztec Corp., an interior design and architectural firm in Iselin, N.J., notes that the open design found at offices such as Children's Place is a growing trend. He said the notion of a private office is fading as clients ask for more workstations and lower panel heights separating cubicles.

“An open office environment allows more communication,” Fournier says. “When you overhear something, you can go over and offer your contribution. Without all the shut doors, you can learn a lot by being able to participate and lend knowledge.”

Still, the debate about open vs. closed office environments continues. Open offices seem to have the edge. With the explosion of the dot-com culture in the late 1990s, communal spaces were all the rage. In the wake of the dot-com crash, some designers speculate the trend might sputter out. But Fournier believes this type of design — which often coincides with hip amenities such as coffee stations and lunchrooms featuring stainless steel fixtures — will maintain its popularity. Aztec featured these amenities in its design of i2 Technologies, a supply chain software company.

“The younger, more entrepreneurial employee doesn't have a preconceived notion of what a work space should be like,” he explains.

As the economy soared in the late 1990s through 2000, employee retention became paramount, and more upbeat office environments became a selling point, he adds. Although the economy is in a recession, Fournier believes that the trend toward open office space will continue as corporations gear up for the next economic boom and seek to attract employees.