When a large earthquake occurs, some structures show great damage and some of them collapse, resulting in human casualties.
If you ask a civil engineer he will tell you that today's constructions are anti-seismic designed.
If after the earthquake some constructions collapse and we have victims, the civil engineer who did the study and the contractor who built the project have problems.
They accuse the civil engineer of incomplete static design, and the contractor of stealing the materials.
Is that so or is something else to blame?
In this article I will try to explain the unbalanced factors that can lie down and the most modern seismic construction, with the best seismic design and the best materials.
I do this for two reasons.
First to dispel the myth that there is an absolute anti-seismic design today.
Secondly, so that civil engineers and contractors are not unfairly accused of not doing their job well.
A rough construction may not suffer anything and the adjacent anti-seismic design may collapse.
How does this happen?
Unstable and uncontrollable seismic factors.
1) Coordination
(Coordination in physics is the phenomenon in which in a forced oscillation the frequency of the exciter is equal to the eigenfrequency of the oscillator, resulting in maximizing the amplitude.
Each oscillator can oscillate in a frequency range.
The instantaneous excitation of an oscillator is equivalent to the efficiency in oscillation of a certain amount of energy. This is free oscillation which occurs at a frequency that is identical to the oscillator's own frequency. When the oscillation is forced, its frequency is the frequency of the exciter. When the exciter frequency is the same as the oscillator frequency we have tuning.
Frequency is the number of repetitions of an event per unit time. Frequency characterizes any physical quantity that changes periodically, that is, it repeats the same values at regular intervals. object)
During tuning the system has the maximum possible width and the maximum possible energy. If there are no damping forces, then the amplitude of the oscillation becomes theoretically infinite. Thus, the oscillation can become so intense that the oscillator is destroyed. If the energy supply is higher, then there is a risk of damage to the oscillator. The glasses have a specific eigenfrequency, which can be heard if we just tap them once. If we emit sound at this frequency, then the glass will oscillate at maximum width until the width becomes too large for the strength of the glass and the glass will break. )
So the frequency of the earthquake is unknown;
The first thing we do not know is the frequency of the earthquake because each earthquake has its own different frequency.
The frequency of the building is proportional to its height.
See in the experiment how structures with different heights react at different frequencies, to understand why even the best constructions are destroyed while the others that do not have an anti-seismic design may not suffer anything.
https://www.youtube.com/watch?v=LV_UuzEznHs&list=LL&index=65
2) Duration.
A construction can withstand high acceleration for a short time or small acceleration for a long time.
If the acceleration of the ground is great and the earthquake has a long duration, no construction will remain upright.
3) Acceleration.
It naturally expresses (or describes) the rate of change of a body's velocity (ie how quickly it changes its velocity, at a random point in time).
Acceleration is basically the variable speed of movement (back and forth) of the structure.
The bigger it is, the more destructive it becomes.
The acceleration that will reach the bottom of the structure (and ultimately the one that measures the risk of destruction) does not depend solely on the magnitude of the earthquake, because the epicenter of the earthquake may be far away so the acceleration that will reach the bottom of the structure is very small.
The soil composition that mediates between the epicenter and the structure is another factor that increases or decreases the acceleration and oscillation amplitude.
The soil agitates the acceleration 2 to 4 times more than the rock.
The constructions are designed to withstand from 0.16g up to 0.36g depending on the danger of the area, and the importance of the project.
Of course they can withstand greater acceleration up to 0.7g if the earthquake does not last and there is no coordination.
The largest earthquake that has occurred in Greece was of the order of 1g
The largest earthquake in the world was of 2.9g and took place in Chile.
Even the maximum acceleration given by seismologists for each area which determines the hazard index of an area and on which the seismic design of structures depends, can be incorrect more than 10%
So the next time you see disasters do not swear that the civil engineer and the contractor are to blame.
Earthquake design is also a matter of cost.
Poor countries can not afford the cost of complete seismic planning.
Something cheap and safe can only come from the anti-seismic design I propose which transfers an extra external force onto the construction, in order to control inelastic deformation.
Today's seismic constructions have exhausted the dynamics they can offer for the following reason.
To become stronger they must increase the volume of concrete and reinforcement.
Increasing the volume of concrete and reinforcement also increases the inertial tensions, so after a point and then it is a free gift.
The external force transmitted by the mechanism of the invention on the structure coming from the ground, is a force without mass so the dynamics of the structure increases without increasing the inertia intensities.
+ many more.
Measured experiment with a natural earthquake acceleration of 2.41g on a scale specimen bearing my patent.
The essay did not suffer the slightest failure.
https://www.youtube.com/watch?v=RoM5pEy7n9Q&t=10s
Hello Ioannis Lymperis
The subject is extremely interesting, but the question is very very long. You could break it down into several small questions (only one paragraph each) for quick answers.
I am not a civil engineer, but as a geologist I would like to know more about the subject of how buildings are affected by earthquakes and how we can help in that direction.
You seem to know a lot about this subject and the readers at RG are all interested to learn more from your research.
Hello Michael Issigonis
Thank you for your kind words I will try as simply and comprehensively as possible. If you speak Greek, become a member of my page
https://www.facebook.com/groups/122735321848311/
Dear Faraed Salman see this link
https://www.youtube.com/watch?v=G5aNjHw27Qs
The general principles to be observed in the construction of such earthquake resistant buildings as specified in this standard are Lightness, Continuity of Construction, avoiding/reinforcing Projecting and suspended parts, Building configuration, strength in various directions, stable foundations, Ductility of ...
https://bis.gov.in › other › quake
IS 1893:1984 Criteria for Earthquake Resistant Design of Structures
Great thanks prof.dr. Iosnnis Lymperis for sharing the link,but it can’t be displayed.
Seismic design is a vital process of structural analysis while designing a building, which is subjected to Earthquake ground motions, such that the facility continues to function and serve its purpose even after an Earthquake.Nov 7, 2019
https://www.enventure.com › blog
Importance of Seismic Design in Building Engineering - Enventure
Also, often the ground storey is a weak structure due to limited ability to carry horizontal forces. Such stilt parkings greatly reduce the earthquake resistance of a building and can fall during the earthquake. It is essential to have properly constructed in-fill walls so as to strengthen the buildings.Apr 30, 2015
https://www.dnaindia.com › analysis
Earthquake-resistant structures: How safe is your home? - DNA India
i) Structures should not be brittle or collapse suddenly. Rather, they should be tough, able to deflect or deform a considerable amount. (ii) Resisting elements, such as bracing or shear walls, must be provided evenly throughout the building, in both directions side-to-side, as well as top to bottom.
https://www.nicee.org › E_Chapter3
GENERAL CONCEPTS OF EARTHQUAKE RESISTANT ...
Shear walls, cross braces, diaphragms, and moment-resisting frames are central to reinforcing a building. Shear walls are a useful building technology that helps to transfer earthquake forces. Made of panels, these walls help a building keep its shape during movement.Feb 6, 2019
https://www.bigrentz.com › blog › e...
How Earthquake-Proof Buildings Are Designed | BigRentz
Under minor but frequent shaking, the main members of the building that carry vertical and horizontal forces should not be damaged; however building parts that do not carry load may sustain repairable damage.
http://www.iitk.ac.in › EQTip08
What is the Seismic Design Philosophy for Buildings? - IIT ...
Braced frames are often used in building walls. Braced frames rely on trusses for resisting sideways motion. Cross-bracing is a technique that uses two diagonal members in an X-shape to build wall trusses and it is a popular technique to build earthquake resistant structures.
https://www.rishabheng.com › blog
Earthquake Resistance Techniques To Protect Against Seismic Threats
Building a structure to withstand seismic waves starts with the right materials with the right properties, and steel is by far the most widely used material for building earthquake-resistant buildings. According to the World Steel Association, ductile buildings are safer as they dissipate energy from seismic waves.Jan 29, 2018
https://newsroom.posco.com › steel-...
Steel Steady: Building Earthquake-Resistant Buildings
https://www.preventionweb.net/files/687_10092.pdf,kindly check this link.
https://www.wbdg.org/resources/seismic-design-principles,pls.check this link.
Dear Faraed Salman
This link now appears;
https://youtu.be/G5aNjHw27Qs
Dear Dr Ioannis Lymperis . See the following useful RG link: Article The Ultimate Anti-Seismic System
Kindly see also the following useful RG link: Article Self-Centering Seismic-Resistant Structures: Historical Over...
Also check please the following good RG link: Article Toward functional recovery performance in the seismic design...
The following link is also very good: https://www.scirp.org/html/6-1880388_59888.htm
Check also the following very good link: https://www.jstage.jst.go.jp/article/journalofjsce/5/1/5_346/_pdf
Dear Aref Wazwaz and Faraed Salman
This link is my patent Article The Ultimate Anti-Seismic System
I introduce in seismic technology something new that did not exist before. I use elongated reinforced concrete walls whose sides are pre-stretched and at the same time anchored with anchors in the ground. This did not exist before as an entity in seismic technology. I stop two causes The deformation of the supporting body and the overturning of the walls and the overturning of the construction. I also increase the cross-sections of the walls in relation to the shear of the base, and increase the capacity of the foundation soil to the loads.
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