Why we cannot protect buildings against earthquakes?

 

Smirnov S.B., Ordobaev B.S,

 Abdykeeva Sh.S, Sadabaeva N.D., Atambek uulu M.

Abstract: At the first it is proposed to analyse pictures and forms of seismic buildings` destructions as unique Sourse of informations about the destructive seismic influence and affect, which must be imprinted at these forms. It is proved that anomalous shear forms of destructions in columns and walls in buildings can be caused only by seismic quasi-chock wave impulses, which cannot be tired by pendulum accelerometers, using now as only seismic devices.

         It is proposed principally new and really effective strategy of buildings` seismodefence, which can protect buildings against destructive effect of seismic wave quasi-shock impulses, which much more dangerous than low-frequent official soil oscillations.

Key words: seismic, buildings, destructions, shear, stresses, wave, impulses, oscillations, accelerations, seismodefence.

         Why do even the most earthquake-proof buildings collapse in spite of all the research and developments of seismists` (those responsible for the seism stability of buildings)?   The usual, common-sense answer would be: because build­ings are still not made to withstand powerful seismic shocks, and it is not far from the truth.

         However, seismists` refuse to believe such a simple explanation. Despite all the facts to the contrary, they stubbornly refuse to acknowl­edge the shocks felt by everyone, believing instead in harmless vibrations which appear after shocks. They continue to think that it these only vibrations which somehow cause buildings to collapse. Therefore, they design buildings to withstand only these vibrations. As a result, large-scale seismic destruction of buildings accompanies every earthquake on the planet. It is important to note that this destruction runs contrary to all calculations and established "norms," and is by no means due to the vibra­tions which worry seismists` so much. For example, a building which is supposed to be "earthquake-proof" to seismic activity up to 7 points on the Richter scale, usually cannot withstand a 7-point earthquake on the Richter scale, and often collapses at 6 points. The form of all seismic destruction is such that cannot be caused by soil vibrations. The seis­mists`  prefer to ignore this fact, which clearly contradicts their theory of seismic vibrations.

What underlies this failure of seismic sci­ence? Let's try to answer this question.

The seismists' failure was predetermined by their initial lack of professionalism. Seismists' background is in seismology, a science which has never had anything to do with the specific questions of building durability and carrying capacity. The seismists' decision to describe the properties of destructive seismic loads and their monopoly in this sphere dealt a fatal blow to all research on "earthquake-proof" buildings. Seismists`  have always believed that seismic destruction is inevitable, and this false idea has led to all their mistakes. In all other spheres of civil engineering, the problem of building col­lapse is handled by experts on the structural durability of buildings, and in these areas, the collapse of a single building is seen as an intolerable catastro­phe The seismists' and seismologists' biggest mistake was made at the very outset of their research, more than 100 years ago. Instead of studying the nature and properties of seis­mic damage to build­ings, and then finding and describing the nature of seismic destructive forces, they adopt­ed an artificially simple model of seismic activity and settled on the easiest, but false, explanation for damage caused by earthquakes. Without any grounds for doing so, they resolved that build­ings collapse because of their resonance reac­tion to seismic soil vibrations, which produce frequency of vibrations needed to destroy each building.

This simple earthquake model clearly has nothing in common with reality. However, it is very alluring to seismists`  because it gets rid of all their difficulties in one fell swoop. They decided to use ordinary pendulums, which reg­ister everything with simple swayings, to formally confirm their simplified theory of sismic destroying soil vibrations.

The adoption of this unfounded model of earthquake destruction would not have had such catastrophic effects if it were not for the seismists' determination to bring it to life. Forgetting that seismic resonance was noth­ing more than a figment of their imagination, they started to build buildings which were immune to this phantom resonance. As a result, the notorious "resonance-resistant" buildings with a flexible first floor were built in many countries of the world. This had mur­derous consequences. The flexible rein-forced-concrete columns on the first floor would immediately snap like match-sticks in an earthquake. This happened everywhere where these buildings were subjected to seis­mic activity: in Chile, Moldova, Romania, Armenia, Greece and finally in the USA and Japan.

After this complete fiasco, the seismists decided to increase the acceleration speed of their soil vibrations and thus to increase the seis-mo-durability of buildings. But this, of course, had no positive effect on building durability. Finally, they stopped talking about the need to protect buildings from resonance. However, their buildings continued to collapse. As a result, the seismists' norms and recommendations    (which had been based  only on counting of son vibrations) lost ail sense and logic.

To crown it all off, on January 17,1995, there was an earthquake in Kobe, Japan, which destroyed hundreds of the newest and most earthquake-proof steel and reinforced-concrete buildings. At the same time, the myth about Japanese advances in earthquake-proof construction (something I had refuted as early as 1992) was also shattered. This myth had been seismic science's last bulwark, and with its destruction in Kobe, this science was left without a leg to stand on.

         After Kobe, seismists`  the world over finally had to admit their mistakes and begin search­ing for new ways to protect buildings from destructive seismic activity. Boasting about advancements in earthquake-proof construc­tion completely stopped in the USA and Japan. Intense work to strengthen the structures once considered invincible and earthquake-proof began. The buildings' and bridges' powerful reinforced-concrete supports were' strength­ened even further with steel bands (a measure which I suggested three years ago).

This was a turning point for seismic science world-wide. By strengthening the supposedly earthquake-proof buildings, the seismists`  in the USA and Japan finally admitted the bitter truth. After the collapse of these "invincible" buildings in Kobe and Los Angeles, scientists were forced to admit that seismostable buildings exist only in their imagination and that not a single city in the world is safe from seismic activity. Furthermore, they admitted that a lot of work will have to be done before such cities are built.

But how can the seismists`  explain away their mistakes without completely ruining their standing in the scientific community^ Simple. They just placed all the blame on the builders. Their accusations ranged from "stealing" cement (in Spitak) and making low quality pan­els (in Neftegorsk) to putting up "too few" con­crete reinforcements (in Moldova, Chile, Greece, etc.). Moreover, the concrete was allegedly so poor that, during an earthquake, it simply turned to dust. These incompetent builders mad§ all of the seismists' innovations worthless, they said.

However, this clearly fails to explain why it is always the earthquake-proof buildings, and only the earthquake-proof buildings, which collapse. The seismists' list of the builders' mistakes and oversights is endless, but upon closer examination and analysis it becomes painfully obvious that all of these accusations are ridiculous. The fact of the matter is that no blunders on the part of the builders could pos­sibly lead to the unusual way in which rein-forced-concrete columns and walls collapse during earthquakes. For example, it would be" hard to believe that the builders were to blame in Kobe and Los Angeles when almost all of the powerful reinforced-concrete supports of bridges and highways shifted sideways and locked in this position without a single crack.

One main conclusion can be made from all of this: thanks to the seismists' lack of profes­sionalism, we still do not know anything about the destructive soil movements and real stresses, which destroy buildings during earth­quakes. Because of this ignorance, we are still protecting buildings from fictitious instead of real seismic dan­gers.

Earthquakes Produce Shock Waves Not only Soil Vibrations

The facts and phe­nomena which I described earlier have always been available to everyone. However, no one paid any atten­tion to them, preferring instead to place blind trust in the seismists`  and seismologists. But now, new facts have sur­faced which help us to reveal the essence of this problem. I will try to show how these new facts could help us to create effective protection mechanisms against seismic shock waves and seismic destruction.

In August 1992,1 had the chance to invest!-' gate seismic destruction in Kyrgyzstan, near the epicenter of the Toluksky earthquake (which registered over 7.5 points on the Richter scale). The earthquake's single, abrupt shock wave toppled several one-story build­ings. It was as if a rug had been pulled out from under them. The buildings' columns and walls were instantly sheared off and fell into small pieces of debris. The damage was clear­ly caused by a single shock. We did not notice any soil vibrations.

Later, for comparison's sake, I worked with a seismic platform which imitated the ground vibrations recorded by the pendulum seis­mometers during the earthquake. I can say with complete confidence that they have noth­ing in common with the seismic shock which flattened those buildings.

Not one of the eye-witness accounts I read mentioned anything about seismic ground vibrations. After interviewing a number of the earthquake's witnesses, it became clear that no one had felt ground vibrations or rockings, but that everyone had felt abrupt shocks or blows. However, these are merely subjective impres­sions, what I needed were irrefutable facts.

Fortunately, I already knew where I could find an endless source of verified information on seismic activity, having used such sources countless times in my studies of other forms of building collapse. The information I'm talking about is sketches and pictures of columns and walls destroyed by seismic activity. These sketches and pictures give priceless informa­tion showing the peculiar networks of micro-fractures, cracks, unusual deformations and amount of debris common to buildings destroyed by earthquakes. All these peculiar forms of seismic destruction reflect the unique properties of real destructive seismic forces, and allow us to describe them.

We studied all this material carefully, finally accomplishing the essential work which should have been done by seismists long ago. We also studied the structural elements of buildings destroyed in the Toluksky and Susamirsky earthquakes, as well as tons of photographs of buildings damaged by natural calamities in different countries. It soon became clear that seismic damage differs greatly from damage caused by hurricanes, large vibrations, etc. We discovered that peculiar forms of seismic destruction and the real effects of seismic shock waves are impossible to reproduce artificially using underground explosions or vibrations of building models on special seismic platforms.

The uniqueness of seismic destruction is in its extremely prolific networks of micro-frac­tures, huge deformations, shearing off of columns, pillars and supports, and, finally, its characteristic splitting of walls and panels into small pieces of debris. This can be seen in the buildings destroyed in Neftegorsk and Spitak, both of which were put down to faulty con­struction. Through direct experiments on models of reinforced-concrete structures, we were able to prove that during seismic activity buildings absorb several times more destruc­tive energy than the vibrations recorded on accelerometers could have produced.

On the basis of this analysis, we described and portrayed the anticipated patterns of destruction which awaited the modern rein-forced-concrete supports of bridges and build­ings in Japan and the USA as early as 1992. Subsequently, these patterns were seen both in Kobe and Los Angeles in 1994 and 1995.

Destructive seismic impulses can only be recorded by highly sensitive non-inertial instruments such as membrane sensors (like those used to measure underground explo­sions). It is namely in underground explo­sions where huge differences are noted between these instruments' readings and those of ordinary pendulums. It is precisely the longitudinal waves caused by the compressional shocks of an earthquake which, in turn, create shear cracks in columns and walls. These waves account for the shearing off of columns and the diagonal or crossing cracks found on the walls.

In order to protect buildings from shear shock waves, we must use the defense mechanisms of objects which are not affected by earth­quakes—such as cars, light box-like garages, ships, people, animals, and so on. In other words, all objects which lie or stand on the earth's surface, but are not rigidly connected to it (and are therefore not affected by the earth­quake's shear shock waves). Light one-story buildings need to be built like rigid, stable boxes which rest upon foundation plates placed fairly shallowly in the ground. Such buildings would be able to "slide" on the foundation plates hit by the longitudinal shock waves, thereby prevent­ing the shear cracks created by seismic impuls­es running along the earth's surface.

As for heavy, high-rise buildings which can­not be "separated" from the foundation plates, in areas of frequent seismic activity they should have a supporting structure made of steel frames, with highly-durable ties and bonds (these buildings' Achilles' heel) which have a special new form and design. Re­inforced-concrete Rahmen and frame struc­tures need to be discarded completely in seismodangerous regions. This is something which became only too clear after the events in Kobe. During earthquakes, steel columns do not shear off like reinforced-concrete ones, because the shearing strength of steel is a hundred times higher than that of concrete.

       It is also possible to use buildings with monolithic reinforced-concrete walls, but the walls of these buildings should be built so as to allow seismic shock waves to travel from the base of the structure to the top unham­pered. This will prevent shear cracks from appearing in the walls (which lead to the build­ings' collapse). To make this possible, ceiling plates should simply hang suspended on the walls, and windows should be rounded off, like on a church, as rounded forms provide a high­er level of protection from seismic destruction.

       There are also other ways to protect build­ings from seismic impulses. For example, buildings can be «shielded» from shock waves with the help of a solid aboveground reinforced-concrete protective plate laid on many thin steel supports (like on a comb). The building would stand on this protective plate, and the whole shearing force of the shock wave would be localized to the steel supports on the first floor.

       To protect people living in reinforced-con­crete panel and block houses (especially in earthquake-prone regions), a stable steel sub­structure needs to be added to the reinforced-concrete walls. These protective substruc­tures can be supplemented to steel corners and to other steel elements and placed on all the corners of each floor to support all floor slabs. After these modifications, even if an earthquake were to shear off the concrete walls of these buildings, the ceiling panels would not fall on the people inside, but would rest on these reserve steel elements.

       Using these truly effective protection mea­sures is no more expensive than introducing seismic belts and other anti-resonance—and worthless—means of protection from seismic destruction.

REFERENCES

1.     Smirnov S.B., 2008, Investigation of anomalous forms in seismic buildings’ destructions, which contradict to official view on reasons of buildings’ destructions at earthquakes, Integrate scientific journal, N9 p.p. 51-59 (translated from Russian).

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3.            Ñìèðíîâ Ñ.Á., Îðäîáàåâ Á.Ñ., Àéäàðàëèåâ Á.Ð. Ñåéñìè÷åñêèå ðàçðóøåíèÿ-àëüòåðíàòèâíûé âçãëÿä. Ñáîðíèê íàó÷íûõ òðóäîâ ×.II,Àéàò, Áèøêåê-2013,-144 ñ.