CHAMPAIGN, Ill. -Soon after the World Trade Center's twin towers were brought down by terrorists on Sept. 11, 2001, some observers questioned whether tall buildings - now viewed as potential targets for future attacks - would continue to be built.
Among those who predicted the world's skylines would not yield to such threats was University of Illinois architecture professor Mir Ali.
"This phenomenon cannot be stopped simply because these two buildings came down," Ali said nearly three weeks after the attacks.
Although he suspected the pace of such construction might slow a bit, he remained convinced that the economic, social and political realities that fueled such construction in the first place would not go away.
As it turns out, Ali - co-author of a new two-volume book, "The Skyscraper and the City: Design Technology and Innovation" (Edwin Mellen Press) - was right.
"There was a little pause after 9/11, especially in the United States," he said. "But tall buildings are a reality that can't be avoided. Wherever you have high population density, you have to build them. And it is happening all over the world."
On the homefront, he pointed to the Trump International Hotel and Tower under construction in Chicago and scheduled for completion in 2009.
"In Asia, there's a lot going up ... in Shanghai and other parts of China," Ali said. In 2009 alone, four other skyscrapers will be added to the world's tall-building inventory: in China, the Nanjing Greenland Financial Center (Nanjing) and Pearl River Tower (Guangzhou); in Singapore, The Sail @ Marina Bay; and in the United Arab Emirates, the Burj Dubai.
The building in Dubai, he said, will be "very very high - rumored to be more than 2,000 feet. That's almost equivalent to putting another super-tall building on top of the Sears Tower."
"The Skyscraper and the City" includes contributions by U. of I. architecture professor and co-author Paul Armstrong and takes root from original lecture notes compiled by Lynn S. Beedle, a professor for many years at Lehigh University who died in 2003. Ali said Beedle, a friend and mentor, was "a distinguished university professor of civil engineering and founder of the Tall Building Council."
The book covers significant ground. In addition to discussing construction processes, materials and technologies, the authors consider such topics as serviceability, safety and security, and cite case studies of a few buildings, including the World Trade Center. They also examine broader issues ranging from the philosophies behind tall-building construction and economic motivations of developers and governments to the needs of people who inhabit the structures.
"The uniqueness of the book comes from the fact that two things are put together," Ali said. "There are books on cities and on skyscrapers. In this book, we show the interdependence between tall buildings and cities. We cannot look at tall buildings in isolation of the city, and vice-versa. They go hand in hand."
What also sets this book apart from existing books on skyscrapers, he said, "is that we deal with the history." And from that history, which can be traced to the construction in 1885 of the 10-story Home Insurance Building Chicago, Ali and Armstrong advanced the discussion forward to consider present and future construction trends and practices. Along with black-and-white and color images of some of the most notable skyscrapers on today's horizon, such as Taipei 101, currently the world's tallest building, the book includes designs of what he calls "visionary" buildings.
"These are megastructures for megacities, where people will live, work and
play - and never have to leave the building," he said.
Ali predicts such megastructures will become commonplace in the world's largest cities, such as Tokyo, which has a population of 34 million. These buildings, he said, will soar to heights of up to 3/4 of a mile, and will likely include not only residences, retail shops and schools, but also internal transportation systems.
Another current trend in tall-building construction examined in the book is one that Ali predicts will continue to take off: sustainability.
"Sustainability of tall buildings is like a theory of architecture," similar to other predominant theories that have been hallmarks of the profession in the past, Ali said. "Sustainability is the present theory. All buildings - tall or not - are moving in this direction, he noted, for two main reasons:
"The first reason is climate change and global warning," he said. "The second is that we are running out of natural resources, specifically, petroleum and coal.
"Because the emission of greenhouse gases is causing global warming, we want to design buildings that are carbon-neutral."
For that reason, architects are increasingly directing their own energies toward innovative alternative practices, with designs that call for solar panels, photovoltaic cells, wind energy and fuel cells.
"The Pearl River Tower will be what is called a zero-energy building," Ali said. "It will provide 100 percent of the energy it uses. It will be completely off the grid." Besides designing the building to maximize the use of natural daylight and solar panels, the tower is punctuated on two levels with open spaces outfitted with wind turbines.
Another innovative example of sustainable skyscraper design featured in the book is the Elephant and Castle Towers, scheduled for completion in London in 2010. Among other "green" features, the building - designed by T.R. Hamzah & Yeang Sdn Bhd - includes the placement of community spaces and landscaped gardens at intermittent heights throughout the building's exterior facade.
Architect Ken Yeang, who had a visiting appointment at the U. of I. last year as the Distinguished Plym Professor of Architecture, is known worldwide for his commitment to sustainability in architectural design. In the book's forward, Yeang noted that while the tall building may be "perhaps the most un-ecological of all building types" - consuming "one-third more material and energy resources in their construction, operation and demolition than the low- or medium-rise building," he, like Ali, remains a realist who knows the skyscraper will continue to serve an important need in the world's burgeoning megacities.
For that reason, Yeang and a new breed of responsible yet visionary architects and engineers designing 21st-century skyscrapers are driven by a singular vision:
"We must make them as humanely habitable and as sustainable as we can."