Buildings have specifications and rules that take into account safety and face the surrounding conditions, and in areas located above seismic foci around the world, these standards are more stringent and more creative, through which buildings are equipped with technologies that help suppress the force of earthquakes.
What are the characteristics of earthquake-resistant buildings?
And how do engineers work to strengthen and design them in a way that makes them not affected by tremors and aftershocks?
What are the most prominent countries that use this type of construction?
What are the most famous international buildings in which earthquake resistance standards are available?
Buildings in general, and those resistant to earthquakes in particular, are characterized by a set of characteristics that make them suitable for habitation and use. These characteristics fall within 3 main axes;
Engineers try hard to reconcile them, in order to ensure the safety of the building, and the optimal way to use it, and these axes are:
Flexibility
There are two main levels of flexibility that engineers seek to ensure;
The first is that necessary to withstand smaller earthquakes, the kind that can strike a building 3 or 4 times during its lifetime.
At this level, construction engineers aim to prevent any damage that needs to be repaired to the building due to these weak earthquakes, which means that the design is tight in a way that enables the building to face any of these seismic tremors without harming it.
As for the second level of resilience, it is the one needed to face very strong earthquakes, which are fewer in number and chances of occurrence compared to the previous type.
In Japan, for example, the level of such tremors was determined based on the intensity of the Great Kantō earthquake that occurred in 1923, with a magnitude of 7.9 on the Richter scale, which destroyed the cities of Tokyo and Yokohama, and killed more than 140,000 people.
Durability
It is represented in modifying and correcting the resistance and stiffness of individual structural elements, or the structural whole as a whole, in order to improve the performance of the building against supposed earthquakes.
Rebar is considered the strongest material in construction, and it is used to reinforce concrete buildings using high-strength steel bars, and diameters range from 6 mm to 40 mm or more.
Iron is used due to its high resistance to compressive and tensile forces with the same efficiency, and it is considered one of the most important ductile materials, which makes it a helper in achieving higher ductility in concrete buildings, with its ability to contain higher loads without sudden collapse.
Aesthetic and creative touches
But the ways to make the building resilient enough to withstand earthquakes are not limited to the use of complex methods aimed at absorbing seismic energy and mitigating the strength of vibrations, but there are other methods concerned with the interior and exterior design of the building and its appearance as well.
The ideal situation is for the building to be as regular and consistent as possible, and if all the floors are of the same height and the columns are in the form of a network separated by equal distances, this increases the building's ability to withstand any earthquake.
But the designers of distinctive skyscrapers are often not willing to make this kind of compromise, which makes it common for discrepancies between the standards required by engineers to make the building capable of resisting earthquakes.
The "Sky Tree" tower located in Tokyo, which is the second tallest building in the world, was built in an architectural style known as "neo-futurism", in which architectural elements are evident from the designs of traditional Japanese temples known as "pagoda".
It also includes a central shaft connected to seismic valves.
The shaft and valves can collectively absorb the energy generated by the earthquake.
Facade of an earthquake-resistant building in Japan (Shutterstock)
Regulatory rules adopted by safety bodies
In various countries, engineering bodies and local authorities adopt to grant building permits legislative and professional standards and determinants, which ensure the required limit of safety standards when constructing buildings. The extent to which buildings comply with safety conditions and the safety of citizens, and the degree of their protection from natural disasters, are monitored. These standards and determinants include:
Determine the map of the faults or cracks between the earth's plates (tectons), which is an important criterion on the basis of which the country's proximity or distance from the risk of earthquakes is determined.
Based on the first criterion, it is possible to determine the specifications of the basic structural materials for building, and their engineering parameters (building codes), based on the geographical and geological location of the country.
The purpose of using the building, whether it is residential, commercial or security, and its size and number of floors have an important impact on the application of regulatory rules.
The material cost is included in these criteria, and higher specifications should not be applied than those required by the geographical area, which would be an unjustified extravagance, and the application of the required specifications should not be tolerated under the pretext of controlling spending.
Anti-seismic technologies
Isolated foundation technology:
It is summarized in the use of rubber bases of a certain thickness, which are placed under the concrete foundations of the building, and their plasticity and flexibility help to absorb and dampen the energy of earthquakes.
This method is widely used in Japan, where 9 thousand buildings use this method.
Other countries, such as Chile, China, Italy, Mexico, Peru, Turkey and the United States, are adopting these technologies to varying degrees. One of the famous buildings around the world built in this way is the Utah State Capitol, which was designed to withstand a 7.3-magnitude earthquake.
Mass Damper:
This technology uses a heavy, swinging mass (made of steel) that acts as a central pendulum designed to swing against the deflection caused by an earthquake in buildings to offset the impact of the earthquake.
Sometimes the mass is designed with fluid moving in the same way as a pendulum (opposite to bend) to reverse the effect caused by the earthquake.
It is noteworthy that the building (Taipei 101) in Taiwan is designed according to this method, in addition to the Burj Khalifa building in the Emirates.
Central bridge technology:
A sliding bridge designed to absorb shocks connects two tall buildings, usually. The "Petronas" twin tower in Malaysia, which was completed in 1999, was designed in this way, and it is the tallest twin tower in the world with a height of 452 meters.
The two glass towers are connected by a central bridge that is designed to slide in and out of the building, and it appears that there are large lateral loads affecting the building.
Calculated collapse:
In the event of a severe earthquake, most American buildings are designed to collapse in a calculated manner, dissipating earthquake energy through damage. The goal is to save lives, but the building — like a car after an accident — will become useless, and some cities are considering San Francisco rules required buildings to be more solid, similar to those in Japan.
Foundation reinforcement:
Creating a flexible foundation can help the building to remain standing during an earthquake, by building a foundation made of reinforced concrete and cross-strips over an intermediate cushion of sand.
Drainage:
Collective water can create structural complications, and it is suggested to build drainage mechanisms to help structures withstand earthquakes.
Structural Reinforcement:
Engineers and designers have various methods of strengthening a building structure against potential earthquakes, which results in the discharge and redirection of seismic forces.
Building with soft materials:
Materials with high ductility can absorb large amounts of energy without shattering, and brick and concrete are low ductility materials, but materials such as modified steel and innovatively reinforced concrete with fibers can provide similar ductility.
A civil engineering company has shown how people in Indonesia can build earthquake-resistant homes almost entirely out of bamboo.
The most famous countries that adopt earthquake-resistant technologies
Japan is the undisputed first country to adopt special techniques in the field of earthquake risk reduction. It goes without saying that this concern came from the fact that the Japanese archipelago is located in a geological area called the "Ring of Fire", prone to earthquakes throughout the year.
There are other countries that adopt advanced conditions in the field of earthquake safety, but they vary in the extent to which they apply these conditions. China, Chile, Italy, Turkey, the United States, Taiwan and Mexico are among the countries that pursue special and advanced policies in the field of protection from earthquakes. away from the earthquake epicenters.
World-famous earthquake-resistant buildings
Taipei 101 Skyscraper, Taiwan:
Taipei 101 is probably one of the most amazing tall skyscrapers in the world.
Aside from the architecture, the amazing fact about it is that it boasts the world's largest tuned mass damper, which is essentially a giant metal ball that counteracts large transient loads such as wind and earthquakes, to reduce the tower's towering impact.
Burj Khalifa
Burj Khalifa in the United Arab Emirates is one of the most famous superstructures in the world, and it is also an earthquake-resistant building.
The columns also help carry gravitational loads, and as a result the Burj Khalifa is very rigid in both lateral and torsional directions.
Sabiha Gokcen International Airport:
It is one of the main airports serving the historic city of Istanbul, and it is also one of the most earthquake-resistant buildings in the world.
It is one of the two international airports in Istanbul, and is located near the North Anatolia Rift.