A high rise building is a multi-story building that rises above the average structure height in a given area. There is no set minimum number of stories. The minimum number of stories generally range from as few as six to ten.
What Are The Key Structural Components of High-Rise Buildings?
Skyscrapers are high rise buildings that are engineered as steel frame structures with non load bearing exterior curtain walls. The height of the buildings requires the use of elevators in order to make access to upper floors practical. HVAC systems are necessary to make the environment comfortable for people.
There are exceptions to the structural definition of skyscrapers. One example is the World Trade Center towers in New York which used exterior load bearing walls. High-rise buildings may also be constructed of high strength concrete columns as opposed to steel.
What Is The History Of High Rise Buildings?
The history of high rise buildings can be traced back to the pyramids of Egypt and the cathedrals of Europe. For centuries, large buildings were made of stone and masonry. This lead to many challenges for engineers looking to build tall buildings.
The largest and highest early structures were the pyramids. Engineering steep vertical stable walls was their challenge. With a wide foundation, they eventually determined the slope that allowed them to build ever higher structures.
In more practical structures throughout history, masonry walls would carry the loads of the building including floors and roof. Higher buildings required thicker walls to carry the increased weight. This also meant openings in the wall could not be very large. Ancient castles and old European homes are an example of this type of structure.
Cathedrals in Europe addressed these problems to create tall open structures with larger openings. Their solution was to add buttresses that provided walls with additional support and spread the loads.
The breakthroughs that led to the modern day high-rise came about in the nineteenth century. The first breakthrough was an elevator that could transport people safely. This was provided by Elijah Otis, who invented a safety brake that would prevent the elevator from free falling in case there was a failure.
The second breakthrough that led to the modern day high-rise was steel frame construction. In contrast to masonry walls that would support the loads of the building, a building would be built of a steel frame that would support the loads. The exterior walls would be non load bearing wall. These walls are known as a curtain walls. This innovation is accredited to William Jenney who engineered the Home Insurance Building in Chicago using this system in the late nineteenth century.
Non load bearing walls had a key advantage. They could have large openings which translated to large windows for light and ventilation. Eventually, HVAC systems would add the third key innovation that has allowed high-rise buildings to develop into the iconic structures we see today.
Why Build High Rise Buildings and Skyscrapers?
Throughout history, high rise structures have been built to demonstrate religious, political and economic power. The same principle can be said to still hold true today.
However, in the modern world, market forces of supply and demand play a determining factor in the high rise buildings that go up today. In certain areas, particularly urban cores, land values are significantly higher than in surrounding areas. Supply tends to be constrained.
Under these conditions, it becomes profitable to build up. In fact, the high land prices may require high rise buildings to achieve the number of units necessary at a high enough lease rate to be economically feasible.