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What is the complex process behind giving birth to skyscrapers reaching nearly 1 kilometer in height?
The tallest building in the world, Burj Khalifa in Dubai, has become an undefeated monument in the field of architecture for over a decade with its towering height of 828m, leaving a profound mark on the minds of architects.
It shattered numerous previous records: towering over its predecessor Taipei 101 by 62%, it left behind a colossal legacy both literally and figuratively for its designers.
That man is Adrian Smith, and the concept of this colossal building gestated when he was still working as an architect at Skidmore, Owings and Merill (SOM). By the time the tower opened in 2010, he had his own company with partner Gordon Gill, abbreviated as AS + GG.
This company specializes in designing super tall and mega tall buildings, meaning those from 300m and above.
Supertall buildings have always been a rarity, with a global list of 173 towers, but megatall ones truly reign supreme with only 3 towers. Some towers have been planned, only to be canceled at various stages. That's why Smith believes there aren't many examples of these projects for people to consider.
Recently, AS + GG also unveiled a book aimed at both students and practicing architects to provide them with an insightful look into how to construct these buildings from a technical design perspective.
They provide examples of recent buildings such as the Central Park Tower in New York (472m), or the upcoming Greenland Tower in Chengdu (468m), with detailed technical drawings. They even provide drafts for concepts exceeding 1 kilometer.
AS + GG's most famous design is the Jeddah Tower (formerly known as the Kingdom Tower) in Saudi Arabia.
The height of the Jeddah Tower is planned to be over 1,000m upon completion, making it the tallest building in the world. Although slated for completion in 2020, by that year, it only reached 58 floors, and the progress was slowed down.
Smith mentioned that construction engineers have 'protected everything they need to protect' and 'the building is not deteriorating'. In response to questions about its continued construction, Gill said 'Never say never'.
Countless intricate problems arise in constructing a 'supertall skyscraper'
Regarding design factors, there are complex elements architects must consider such as the application of technical advancements, from wind resistance tests at a scale of 1:4000, to strategies for minimizing solar radiation, or systems for recovering stagnant water capable of collecting the equivalent of 14 Olympic-sized swimming pools each year...
The book points out that Jeddah's structure learned and refined from Burj Khalifa, with a 3-armed Y-shaped design to maximize stability. Smith also mentioned both towers drew inspiration from the Friedrichstrasse skyscraper over 100 years ago.
However, he also admitted that many concepts have been conceived but not implemented. Nevertheless, they still hold learning value, some of which are Meraas Tower (526m), Za'abeel Signature Tower I (598m), and 1 Dubai Atrium City (1,000m) (all planned in Dubai).
Gill stated that 'tons' of lessons from these buildings have been applied in other AS + GG designs. For example, the development of the 1km-high 'vertical city' concept in Dubai has spurred discussions on mechanical systems, structural efficiency, elevators, fire safety, air and light, among countless other topics, 'becoming a larger dialogue around height'.
For the 1km-high Dubai concept, designers have ideas to use 3 interconnected supertall towers through a central system to maintain stability.
Beyond considerations of height - the most commonly discussed aspect of skyscrapers, Smith argues that it's just the starting point for a host of other discussions about architectural themes and urban problem-solving.
The book suggests that supertall and megatall buildings could help advance ideas about energy efficiency, carbon footprint reduction, and the connection between built environment and nature through biophilic design (a new design trend integrating natural experiences into living spaces).
The Biophilic Tower, an unrealized design since 2012 intended for Taichung, China, diverges significantly from conventions, featuring a spiraling vertical forest with 119 floors and sunshades inspired by leaf and beehive structures.
The issue, Gill points out, lies in people often not understanding the deep-seated factors behind the science and engineering of these marvels, despite them being crucial elements that make the buildings magnificent beyond their towering heights.
Tall buildings come with all sorts of mechanical and structural challenges. There are countless questions regarding logistics like how long people might wait for an elevator ride from the lobby to the 200th floor.
How megastructures will withstand both predictable natural forces and those we cannot anticipate is a pressing question. Many of these issues are addressed by leveraging modern materials and systems we're familiar with, as well as creating new and improved materials and systems. Essentially, when such a grand project is completed, many technical and structural barriers have been overcome.
Another critical issue regarding structure to keep such a building standing is steel replacement. For this puzzle, aluminum offers a lighter alternative to steel with an extrusion process that easily conforms to various facade designs. It also reacts well to stresses from internal structural factors and external forces like rapidly changing temperatures and seismic disruptions.
Carbon fiber is another emerging material, also lightweight, but with long fibers interwoven to form a fabric-like structure. Consequently, it's significantly stiffer than steel, allowing it to be used in buildings subjected to high impact loads. Carbon fibers are already being integrated into precast concrete elements.
Also stemming from skyscraper design and building material research, ideas for replacing concrete - a construction material largely unchanged for centuries - are emerging. Though durable, it's a significant source of CO2 emissions.
Some researchers are exploring bio-concretes, capable of self-healing cracks by introducing limestone-producing bacteria that can extend concrete lifespan up to 200 years. Even wood, seemingly never used as a primary structural component in supertall structures, is being applied in layered structures to achieve strength equivalent to steel.
To demonstrate wood's potential, SumitomoForestry, a design firm based in Japan, recently unveiled plans to construct a 350m-tall wooden architectural project in Tokyo. Taller buildings are on the horizon, and materials as well as construction methods are rapidly catching up to turn these mile-high dreams into reality.
Source: Compilation
