A skyscraper is a building that reaches a height of at least 100 meters (328 feet). While the term “skyscraper” is often used to describe buildings of 10 or more floors, it has been argued that the best definition is the one that defines a building by its function, not by its height.
This definition would permit buildings that are each one floor high, like often-overlooked townhouses, to be called “skyscrapers”. However, thanks to the Skyscraper Index, a comprehensive ranking of the world’s tallest buildings, a clear majority of skyscrapers can be defined as “megatall” buildings, defined as at least 200 meters (656 feet).
Even today, the technical challenges of building supertall skyscrapers are considerable. Tall buildings present complex, unprecedented challenges for the building industry and its professionals. They also present unprecedented opportunities for creative engineers, architects, and contractors to meet those challenges in novel ways.
While there are many different types of skyscrapers, they all have one thing in common: they are all very tall buildings.
How tall is a skyscraper?
The height of a building is usually measured from the bottom of the foundation up to the top of the architectural peak, which by convention is usually the tallest point of the building. The taller the building, the larger the building floor area required to house the building’s occupants, so the more people the building can accommodate.
The population living in a city sometimes increases exponentially with the building of a new skyscraper, and the increased living area provided by a tall building can be crucial in controlling the growth of a city. In 1962 the Burj Khalifa, located in Dubai, was completed and became the tallest man-made structure in the world at 817.8 m (2,717 ft).
The Skyscraper Index was developed to help distinguish between different types of tall buildings. The Skyscraper Index ranks buildings on a scale from zero to nine, nine being the tallest and zero being the shortest. The Skyscraper Index is calculated by dividing the building’s height in metres by its floor area in square metres. The Skyscraper Index is intended as a guideline to help architecture and urban planners understand the impact of different building heights on a city.
A Brief History of Skyscrapers
The Rise of Skyscraper Building in the Industrial Age
The Industrial Revolution in the late 18th and 19th centuries saw the rapid growth of cities around the world. With more and more people moving to the cities, there was a pressing need for new housing. At the same time, there was a lack of sufficient space to build these new homes, because previous building techniques had primarily focused on small dwellings.
This led to the development of “vertical housing”, which uses the entire city’s available space for residential, commercial, and industrial uses.
One of the first examples of vertical housing is the “Krupp’s Industrial Plants in St. Louis”, which was completed in 1877 and is still the tallest building in the state of Missouri, USA. The steel frame was invented in 1879, allowing for the construction of much taller buildings than previously possible.
The Rise of Skyscraper Building in the Modern Age
With the invention of the elevator in the 19th century, building heights could be increased dramatically. This led to the construction of the first skyscrapers in the 1880s, including the “ Singer Building” in New York City, USA, which used the elevator to reach an altitude of 10 floors.
The first decade of the 20th century saw the construction of even taller buildings, with the “Petroleum Building” in Houston, Texas, USA rising to 16 floors and 207 metres.
The rise of the modern tower
The structural design of a modern tower is based on the “tube and tube frame” method, which uses reinforced concrete as its main structural element.
While a modern tower may have a mainly commercial purpose, such as an office building or a hotel, it may also contain residential units, such as a condominium or a high-rise hotel.
At the top of the skyscraper food chain, in terms of global height, is the “Burj Khalifa” in Dubai, which stands at 828 feet (247 meters). The “Taipei 101” in Taiwan is the second-tallest building in the world, standing at 1067 feet (333 meters).
The Technicalities of Building Tall
Before construction can begin on a skyscraper, the architect must first decide which types of building materials to use. For example, steel frame buildings can be taller and thicker than concrete buildings, but they are more difficult to build because the steel requires advanced techniques to reinforce and shape.
Using the appropriate tradeoffs, the architect determines the appropriate building height and use of materials to maximize the building’s structural efficiency.
Over time, the natural limitations of building technology and the need to protect human life have led to a number of safety and health regulations affecting skyscrapers.
The technical challenges of building a skyscraper are considerable, and engineers and architects have been pushing the boundaries of what is possible in the design and construction of skyscrapers for decades.
The technical demands for building a tall building are significant, and some of the most significant challenges in skyscraper engineering include the following:
- The wind challenge – The weight challenge – The seismic challenge – The budget challenge
The wind challenge
The wind challenge is perhaps the most obvious one, but it is also the most difficult to overcome. Tall buildings are often constructed in areas that are near to other buildings. Therefore it is important that the wind is taken into consideration when building them.
The weight and seismic challenge
Tall buildings can fall over if there is an earthquake and the designers didn’t take this into consideration. This is why a lot of time is spent finding the right weight distribution and adding measures that allow the building to deal with shocks.
The budget challenge
Buildings have to be built with limited resources. Finding the right combination of materials can be challenging and project managers have to make sure that everything happens on time and within budget.
To conclude, we can state that skyscrapers have evolved a lot over time. They have become more common in the past centuries as megacities have developed and grown. We can expect that these big towers will keep their relevance for the foreseeable future.
Skyscrapers often use modern building techniques such as curtain walls. This allows them to offer something unique to their inhabitants and can impress visitors.