How Can Buildings Effectively Withstand Earthquakes?
One of the essential components that architects consider the most when designing a building is how it can withstand external elements such as earthquakes. Several international building regulations control the design and construction of new residential and commercial buildings. One of which is seismic codes that help mitigate the devastating effects of earthquakes and ensure that a structure can withstand its force.
Several high magnitude earthquakes caused extensive damage to its path throughout history. However, most of the injuries and casualties attained during earthquakes are a result of collapsing buildings with people inside them. This realization makes seismic-proof strategies extremely crucial in many structures today.
But before we dive right into the techniques involved in making your building seismic-proof, understanding earthquakes is necessary to form a solution to reduce its destructive nature accurately. It is also critical to understand its effect on manufactured structures, especially since most people live and work in tall buildings.
What Are Earthquakes And Its Impact On Man-made Structures
Even though there are millions of earthquakes every year, only a handful are mighty and destructive. By definition, earthquakes happen when two earth blocks slip past one another. Earthquakes generally fall under four categories, which are:
- Tectonic – These earthquakes occur due to suppressed and accumulated pressure between tectonic plates that have locked onto each other. The rest of the plates keep moving, increasing pressure on the closed section. The locked plates will eventually succumb to the pressure, releasing energy and causing the earth to shake.
- Volcanic– From the term itself, volcanic quakes are caused by a slip near a volcano. These quakes occur due to the regional strain exerted in an area of weaker faults. While volcanic tremors are typically lower on the Richter’s scale, they still can cause damage and ground deformation.
- Collapse – This type of earthquake is generally smaller and less prevalent than tectonic quakes. Collapse earthquakes typically occur inside underground mines due to the pressure generated within the rocks. The stress then instigates the earthquake, leading to the mine roof’s collapse.
- Explosion – The cause of explosive earthquakes is massive explosions triggered by human activity such as mine excavation and nuclear tests.
Apart from the devastating nature of earthquakes, they can also trigger other damaging effects. They include tsunamis, damage to buildings and infrastructures, landslides, and even floods.
Making a Building Earthquake-Proof
Engineers must reinforce the foundation and counteract an earthquake to successfully design and ensure a structure’s resiliency against earthquakes. Since quakes tend to release energy that pushes on a building from one direction, the goal is to go the other way. Here are some of the most effective methods to help buildings withstand earthquakes.
Create a Flexible Foundation
Base isolation is an effective way to resist ground forces by lifting the building’s foundation above the earth. It involves the construction of a structure on top of flexible pads made of steel, rubber, and lead. This method effectively absorbs seismic waves by vibrating in earthquakes, maintaining the building.
Counter Forces with Damping
Shock absorbers aren’t just used in cars, as engineers use them to make a building resilient to earthquakes. They can effectively reduce the magnitude of shockwaves and help a building slow down. Damping is accomplished in two ways, via vibrational control devices and pendulum power.
Shield Buildings from Vibrations
Instead of counteracting ground forces, researchers are experimenting with other ways on how buildings can deflect and reroute the energy from earthquakes altogether. Called the seismic invisibility cloak, this ingenious innovation involves creating a shroud of 100 concentric plastic and concrete rings and burying them at least three feet beneath the building’s foundation. The seismic waves would then be forced through the outer rings for more accessible travel in an earthquake.
Reinforce the Building’s Structure
To not easily collapse, buildings must effectively redistribute seismic waves. They do this by using shear walls, diaphragms, and moment-resisting frames.
- Shear walls are beneficial when reinforcing a building as it helps transfer the earthquake’s force. Made of steel beam panels, its ability to support compression and tension helps counteract the pressure.
- Diaphragms support the building internally, as each deck supports all floors by removing tension and pushing force toward the vertical structure of the building.
- Finally, moment-resisting frames offer more flexibility when it comes to building design. Builders place this device between the structure joints, allowing the columns and beams to bend as the joint remains rigid. As a result, the building can resist strong earthquakes while allowing the designers to arrange the building’s elements.
While the devices mentioned above primarily help dispel seismic waves, the materials used in a building are equally responsible for ensuring its stability and resiliency. Using these materials during the construction phase and installing weather-resistant equipment such as ship stair hatches can further enhance your building’s resiliency towards earthquakes.
- Steel and Wood – For a building to resist stress and vibration, it must have high elasticity. Builders often use structural steel to build modern structures. Structural steel is a steel component that allows facilities to bend without breaking. Wood is also an effective ductile material due to its high strength relative to its lightweight configuration.
- Innovative Materials – Technological advancements have taken us to such great heights. Also, since scientists still cannot predict when earthquakes will occur, they instead made incredible innovations to help reduce its devastating effects. It involves using shape memory alloys to endure the heavy strain and revert to their original shape. On the other hand, fiber-reinforced plastic wraps can be wrapped around columns and provide up to 38% greater strength and ductility.
Over the years, engineers have developed practical techniques to support a structure’s stability and resiliency towards earthquakes. While we are now more advanced than ever, we can still accurately identify when the next quake will hit. We can also predict how a building can completely resist a powerful earthquake and remain unscathed. However, if these methods and devices can save lives, we can consider it a great success.
Chris Jackson is an experienced Business Development Manager with a demonstrated history of working in the construction industry. He is currently employed by Best Access Doors, an access door supplier in the US and Canada. He has been working for the company for more than 12 years now. His area of expertise is on Negotiation, Roofers, Sales, Project Estimation, and Facility Management (FM)