In this article, we will briefly discuss how to build earthquake-resistant buildings.
As we all know, one cannot defy the nature action but with certain measures and engineering application, it can be achieved to a certain level but not completely.
Infrastructures are most likely to be the main victims of natural calamities like earthquakes, floods, etc.
To overcome these disasters, A building must be built with proper planning while considering present and future mishaps.
Before you jump on how to build earthquake-proof buildings you need to know what is earthquake and how it is caused.
What Is Earthquake?
An earthquake can be defined as – Any sudden shaking or disruption in the earth layer that results in causing shock waves in the earth’s lithosphere that create seismic waves.
There are mainly seven large lithospheric plates in the earth’s crust, any movement of these plates causes sudden releases of stress along faults in the earth’s crust.
A steady build-up pressure is created in the earth’s rock strata following the continuous motion of lithospheric plates until the stress is great enough to be released in a sudden.
These waves of seismic energy transmit through the ground result in shaking of the earth which is usually called an earthquake.
Reason For Building Failure During Earthquake
1. Failure of Soil – Earthquake can create a force that is enough to turn soft soil into quick sand thus eliminating its ability to bear the structure weight.
2. Failure of Foundation – All structures can carry their own loads, but buildings are not particularly designed to resist irregular, multidirectional, and intense side-to-side loads that occur during an earthquake which result in the crumbling of structure.
3. Failure of Joints – When there is not sufficient clearance between the different structure, and when joints in column and beams are not allowed to bend may lead to crumbling during an earthquake.
4. Failure of Design –If a structure is not designed to undergo high ductility and ability to resist seismic waves that may lead to disastrous in an earthquake.
5. Failure of Material –A building material that cannot withstand seismic vibrations or poor-quality materials may lead to building failure during an earthquake.
How To Build Earthquake-resistant Building
Infrastructure is more vulnerable to crumbling during natural calamities like earthquakes, Tsunami, etc. but to reduce the chance below are some points you must consider to build earthquake-resistant buildings.
1. Resistible Foundation
Foundation is the most important step for any construction as it carries the structure load, But the same type of foundation can not be applied for all structures it must be designed accordingly.
While in case of building earthquake- resistance buildings, the structure must be constructed on the top of pads which are usually made up of steel rubber and lead.
Which separates the building from the ground and prevents transmitting seismic waves through the building. So when an earthquake is caused only the pads move and the building stays steady.
2. Seismic Dampers
Seismic dampers are used in building structures to restraint the oscillations of the building during an earthquake.
There are many different dampers are available for a structure but among those damping through friction is the most efficient way of dissipating kinetic energy through friction.
These dampers allow the structure to move elastically and dissipate the energy of an earthquake.
3. Vibrational Control Devices
Vibrational control devices are proven to be most workable in seismic hazard mitigation approach in different structural designs. These vibrational control devices are commonly used for energy absorption.
These devices are generally adopted in Mid- and high-rise buildings as an energy-absorbing system to resist seismic and wind waves.
4. Cross Bracing System
Using a Cross bracing system in a building structure can help to build earthquake resisting buildings when cross bracing is utilized to reinforce building structures in which diagonal supports intersect. Cross bracing is commonly seen in bridges with two diagonal supports placed in the form of an X-shaped manner.
During an earthquake, this bracing will bear lateral forces such as seismic or wind waves. While one brace is under tension the other one will be compressed
These are usually seen in bridge supports and structural foundations.
A diaphragm is basically a floor, roof which transfers the lateral forces of the building to the vertical elements.
Diaphragm also ties vertical elements together and stabilizes and transmits forces among these elements as required during earthquake shaking.
Diaphragms are an essential part to build an earthquake resisting building and this seismic force-resisting system must be considered while designing the building structures.
6. Shear Wall
Shear walls are structural members mainly used in RC framed structure resist lateral forces such as wind and seismic forces.
For tall buildings, it is a good option to use shear walls. They provide stability of the members to create a rigid, moment-resisting frame.
As said earlier shear walls help to resist seismic forces in high-rise buildings, it should be considered to build earthquake resistant buildings.
7. Use Earthquake-Resistant Materials
The building material plays an important role in constructing earthquake resistant buildings, the lower the quality more prone to earthquake.
The materials must be highly ductile and must have the capability to undergo large deformation and tensions. Some of the materials like steel, wood which are highly ductile and can withstand the earthquake So, it is recommended to use only proven and tested materials.
With modern engineering innovation, many building materials are developed which has greater shape retention than the standard materials such as Memory alloy – it can undergo heavy strains and can revert to its original shape.
Fibre plastic Wrap – Which is usually made of different polymers can be covered around the columns, which provides greater strength and ductility up to 38%.
8. Load Consideration
A structure always is designed based on the load consideration, the larger the load stronger the foundation should be. Any additional structures in the building can add extra weight to the structure.
As you can see the tall structure usually be in narrow shape as they move high because providing wider surfaces in the lower floors than the upper floors can reduce the chance of crumbling to the earthquake.
During the earthquake the bonding stirrups and concrete weakens, making it likely to collapse. One can consider using Polyurethane (PU) which is a type of insulated panel that comes very lightly and has the highest insulating factor which helps in strengthening the building structure.
9. Look For Expertise In The Field
Anyone can construct a structure, but when you consider building Earthquake-resistant buildings look for expertise in the field who has proven knowledge in designing.
The design must give priority to ductility and the ability to resist the earthquake without crumbling the structure. Many professionals recommend ductility can be improved when mass and strength are distributed in a structure.
It is also recommended that site location must be chosen away from fault lines or volcanoes that are more vulnerable to cause damage during earthquakes.
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