Architectural Wonders - The History and Future of

SkyscrapersBy Kenny Slaught

The idea of a “skyline” has become the predominant way in which we see our cities. On keychains and postcards sold across the world, cities are defined as the silhouettes of their buildings. The stars of these images are skyscrapers, the towering structures that have become central to our understanding of urban life.

Today, skyscrapers have become incredibly tall structures. The tallest, Dubai's Burj Khalifa, extends 2,717 feet above the ground, comprising some 160 floors of residential and commercial space. While experts disagree about what the skyscrapers of tomorrow will look like, it's abundantly clear that today's cities are the culmination of architectural dreams that humanity has nursed for thousands of years.

A 4,000-Year Quest for Greater Heights

Architects and scholars have been arguing over the precise definition of “skyscraper” for decades. While a rough consensus exists around the idea that the first proper skyscraper was the Equitable Life Assurance Building, a 130-foot Manhattan structure completed in 1870, there remains a contentious debate. Architects have also kept skyscrapers separate from other structures, such as radio and television broadcasting towers, which have only recently been surpassed in height by enclosed structures.

Definition

Historians are much more comfortable in discussing the origins of humanity's fondness for tall structures, which can be traced back as far as 2650 BCE, when the Great Pyramid of Giza was finished.

At 481 feet tall, the resting place of Pharaoh Khufu served as the world's tallest structure for thousands of years.

History

Advancement

Throughout human history, buildings have grown taller as materials have become stronger and engineers have grown more proficient. Builders were unable to match the height of the Great Pyramid of Giza until medieval times, when masons became proficient in the use of flying buttresses and other building techniques that gave rise to such wonders as Salisbury Cathedral, which reached 404 feet more than a century after construction began. By the 1800s, cast iron had entered the architectural lexicon, with structures like the Duane Street Factory and London's Crystal Palace, and techniques like prefabrication. By midcentury, the advancement of industrial steel production as a result of the Bessemer process allowed for even greater architectural marvels. However, while buildings could become far taller with steel skeletons, the final ingredient necessary for skyscrapers was the elevator.

Modern Engineering Marvels

In many respects, elevators were the key to humans living in the skies. The invention of the Otis elevator safety brake in 1854, as well as other advancements, made it possible for buildings with dozens of stories to be regularly inhabited, as few people wanted to live and work in spaces accessible only by countless flights of stairs. Architects took the elevator and ran with the concept. By the late 1800s, buildings began brushing the clouds at a frenzied pace, driven by the twin Chicago and New York Schools of Architecture.

By the early 1900s, buildings like Philadelphia City Hall and New York's Singer Building had finally begun routinely outclassing the Great Pyramid. It took a century for steel, glass, and concrete to finally begin reaching their limitations with structures such as the Citigroup Center, which introduced mass dampers in order to counteract the forces of the wind. Today, as skyscrapers grow taller, technology has strived to keep pace with engineering challenges, with advancements such as beam-supported floor slabs, outrigger trusses, friction piles, and refuge floors used to allow skyscrapers to withstand typhoons, earthquakes, and other natural disasters.

Challenges for the Next Generation of Skyscrapers

Despite the fact that architects and engineers have conquered gravity and nature alike in the quest for taller buildings, challenges remain for those looking to reach even greater heights. One major issue is sustainability and efficiency. While skyscrapers may be iconic and beautiful, they require significant energy and manpower to build and maintain, as well as significant support from municipalities.

The energy problem will likely be solved through the smart use of big data. Networks of thermostats, lighting fixtures that respond organically to natural light sources, and other tools will be key to enabling sustainable structures and prototypes like The New York Times building to provide a glimpse of the greener future.

Meanwhile, engineering problems that still must be solved bedevil every aspect of skyscrapers, including their central feature: the elevator. Steel cables and traditional motors can move people at high speeds. The forthcoming CTF Financial Center's elevators will jet along at 20 meters per second, but even they have limits.

Rope-free systems that depend on magnets, such as those being developed by ThyssenKrupp in Germany and Hitachi in Japan, may help to alleviate the engineering limitations created by traditional elevators.

Touching the Sky and Other Future Dreams

At 2,717 feet tall, the Burj Khalifa represents the pinnacle of structural engineering, but it may not represent the future. Scientists, engineers, and architects have long questioned what the future of skyscrapers will look like. As buildings are shaped by their users and inhabitants, it may be that the skyscrapers of tomorrow will be more like the Great Pyramid, with massive cities growing ever upwards on top of themselves.

Alternatively, they will be contorted into shapes unrecognizable by future architects, who may use the next generation of building materials to create towers shaped by the inhabitants' desires rather than by the strict rules of engineering.

However, the sky above remains a constant goal, and other scientists have ideas for structures that dwarf today's skyscrapers. One enduring concept has been the space elevator, a structure that extends from the surface to reach space far more easily than traditional rockets.

While current technology does not allow for space elevators, promising materials like carbon nanotubes or diamond nanothreads may allow for the creation of an elevator that extends from the ground to geostationary orbit, some 35,800 kilometers above sea level.