To Protecting Buildings from Collapses by Earthquakes, Accidents and Terrorist's Acts
Between 1950 and 1970 the former Soviet Union underwent a rapid growth of mass prefabricated urban construction, which, although the technical policies were not sufficiently unified, to a great extent enabled the acute housing crisis in the country to be solved. This led to a number of serial projects of blocks of flats with few architectural differences, but a variety of non-unified parameters for layout and design, chosen according to the required degree of safety and cost-effectiveness. The absence of standardization of the basic construction parameters resulted in theautonomous development of each range, causing a dramatic increase in the overall quantity of typical dimensions of each member. This gave rise to a paradoxically unfavorable situation for the construction industry on the one hand, which was more effective in conditions of mass production of a minimal nomenclature of structural elements, and was forced to produce them in small batches each corresponding to a huge quantity of different grades, and on the other hand for the consumers who were interested in the diversity of the final product (buildings and premises), but had to make do with the meager selection that was offered them. Although the architectural poverty is obvious at first glance, the safety of the load-bearing systems is only revealed by analysis, building, operation of the structure and inspection (and also by accidents and earthquakes). As for the cost-effectiveness of the structure under the socialist system, they are of a fairly conventional character and do not fully reflect the real correlation between the expenses and their conformity to the operational and aesthetic quality of the structures achieved. Russia's transition to a market economy, which aspires to a dynamic equilibrium of the monetary-commodity relationship in its final stage, at first, enabled the disproportion between the cost price and the market price of property to increase. This led to a redistribution of resources. The State financing of large-scale industrial construction dropped sharply, whilst there was a considerable increase in private financing for the less economical and less industrial construction of prestigious buildings, individual "cottages" and private residences (often like palaces), as well as in the amateur building of rural dwellings (as good as shacks for their comfort and architecture), and "dachas" (as a rule far from Moscow, but sometimes for their comfort and architecture not far off from dogs' kennels).
Thus architecture, the most objective form of art, reflects the social and economic stratification process which is taking place in the country (it had been going on even earlier, only was usually concealed behind silent walls).
Along with the destructive phrase: "Peace with the slums, war on the palaces!” it would be more sensible to follow the slogan of Mao Dzedun: "May all the flowers bloom!" However, earthquakes preferred destroy mainly the low slums,but not the palaces, weeds propagate themselves, Mao andother dictators preferred to shortenfirst of all the highest flowers (by cutting their heads).
Author of this article, to bi “christened” to “large panel buildings protector” by the earthquakes in Tashkent 1966, had began to make attempts for protecting as “the slums” so “the palaces” (not only of large panels) from failures by earthquakes, accidents and terrorist’s acts.
In the USSR “all the flowersbloomed” in buildings constructions sphere, except large panel buildings with height more 5 stories in high seismic active zones.
On the base of analyze experience receiving in Tashkent, consequences of numerous other earthquakes and accidents, scientific and technical information author attempted to lead himself “selection” from different constructive “flowers” for application in high seismic active zones. In result, it was decision, to accept exactly unauthorized large panel structural system for construction multistory buildings in condition of mass construction in high seismic active zones of the USSR. Though employed large panel buildings technical solutions of prefabricated elements, joints und bindings didn’t for providing a perception of high seismic stresses.
For leading theoretical investigations on mathematicians models author was necessitated to work out calculate method and program automatic calculations for buildings fragments (by help mathematics Naum Lebedinsky and Aleksey Kuzmin) with regard unelastic deformations large panel structures (from elastic stage work of statically indeterminate system to transformation it to mechanism) by stress of strong horizontal forces.
There were exposed great influence horizontal joints opening and cracks formation in flat arches on interworking bearing system elements and onchanges of building’s dynamical parameters.
For the first time In the end of 60-th and beginning of 70-th it was worked out principal new large panel buildings constructions, including reinforced concrete flat elements, precast and cast-in-situ joints and space structures, formed by them, that provide the best conditions for three-dimensional collaboration all elements of bearing systems by high earthquakes.For that it was proposed to fabricate all panels with corrugated lateral edges and to place in cavity, formed by them, main continuous vertical and some horizontal armature and following monolith them by fine-grained concrete. After conducting some laboratory tests of buildings large scale models, elements and joint fragments on a natural scale there were formed albums technical solutions of elements, joints and most reasonable space structures concerning (without patenting) that were send round scientific and design institutes, occupied with seismic resisting buildings.
Realization some of those technical solutions in mass building constructions and testing them by real earthquakes corroborated their effectiveness. Some of them demandedfurther improvement and development.
Unfortunately,as a rule, in our country realization rational technical solutions was and is joined with necessity of overcoming bureaucrat’s resistance and don’t have any positive feedback coupling for their authors.
In spite of bureaucrats attempt to “perform a circumcision” of his creative ideas realization, and in case of success as a result of his ideasrealization – to “perform a circumcision” the author himself from the fruits of one's creative work, even if he had registered certificate of authorships (what was happened extremely rarely through his “laziness” and absence back favorable coupling). But on the other hand by the mass industrial building construction in our country realization new technical solutions thru typical project brings large economical effect. Though it is very difficult for author to receive even insignificant part of it.
There are some photos of this buildings failures by earthquakes 1966 in Tashkent (Uzbekistan).
Photos 1 - 3. Failure old dwelling houses (“slums”) with bearing mud brick walls, strengthened by wood frame. The last photo – The first attempt of author to prevent from a dwelling house collapse.
Photos 4 - 6. Partial damage public buildings (“palaces) with bearing walls, strengthened by monolithic reinforced concrete frame brickwork (construct in 50–th).
Earthquake has showed absolute instability agents seismic native Uzbek houses of type “machala” with bearing mud brick walls.
In numerous native appearances and publications substantiated advantages large-panel structural systems in comparison with brick, block, frame and mix structural systems, that wasconfirmed by mass constructions and by aftereffects analysis of destructive earthquakes, accidents and acts of terrorism.
However a lot of faulty and dangerous structural decisions were included in numerous scientific investigations and “successfully” defended doctor’s dissertations. The most trouble – some of them were realized in mass buildings construction that led to numerous of victims by this time and can lead to much more.
It’s pity, in our country human lives have too low value, that can’t be say about price of buildings, especially in the last time before today’s Crisis.
Some examples of destructive earthquakes took place in Armenia in 1988, when were collapsed near all houses withbearing walls of small tuff and large tuff-concrete blocks and with bearing prefabricated reinforces concrete large-panel-frame structural systems of the first stories.
The main causes of buildings collapses were following: defective bearing structural systems with flexible frame of the first stories; absence or lack of girds providing space interaction bearing elements, low load-carrying capacity of tuff blocks and low class of cement mortar.
There are some following photos after destroyed earthquake 1988 in Armenia.
Photos 7-9. Collapses of 5-story dwelling houses with bearing reinforced concrete frames of the first stories and tuff-concrete inner walls of large bloc and external walls of small tuff blocks of 2 - 5-th stories in Spitak (Armenia).
Photos 10 & 11. Failure 5-story dwelling houses with bearing large tuff-concrete blocks inner walls and external walls of small tuff blocks, strengthened by monolithic reinforced concrete frames in Spitak.
The destructive earthquake 1988 in Armenia confirmed higher seismic resisting of large panel bearing systems. But only by rationale solutions of structural schemas and butt connections, that create monolithic polybrochate prismatic shell structures.
None of the 16’s 9-story large-panel buildings (of the A-451 series) with precast-monolithic joints, made by corrugated lateral edges of walls and floors panels (worked up by author concerning to cavitated wall and floor tuff-concrete panels) had any damage (including 2 of them - in process of assembling).
In this time were collapsed all of the 9-storeis frame-panel buildings located near to the 9-storeis large- panel buildings.
Photo 12. Demolished 9-story frame-panel Photo 13. One of the large-panel building in process of building (foreground) and safety 9-story large- assembling after earthquake in Leninakan. You can
panel building (background) in Leninakan (now see corrugated lateral edges of walls and floors panels Kumairy)after earthquakein 1988.
Photo 14. Destroyed frame-panel Photos 15 & 16. A “saved” family onwindowsill of undamaged large- buildings in process of assembling. panel building and author on roof one of them against the background
of “field of battle Nature against Man”.
Photo 17. 9-story large-panel buildings (of the A-451 series) without any damages among ruins of 9-story frame-panel buildings (based on prefabricated frame series II-04) after earthquake of 1988 in Leninakan.
In spite of absence of any large-panel buildings damages, all their dwellers had leaved them together with furniture, equipment and window frames, to by afraid of their houses collapse, like next door one.
Altogether were amount over 25 thousands of perish by earthquake of 1988 in Armenia.
There isn’t known how many lives of dwellers in these buildings were saved. But it is known that among numerous awarded for this there wasn’t author of buildings structures. It is normal for our country, where as a rule “are awarded not implicated and punished not guilty”.
In the 1995 strong earthquake in Neftegorsk (Sakhalin Island) destroyed practically all 17 the 5-story large-block buildings (of the 110 series) collapsed as a result of their insufficiently earthquake-proof load-bearing systems due to weak ties between the concrete wall blocks and thefloor slabs. Happened at night, earthquake turned the entire city into cemetery of communal graves.
Fhoto 18. Failure all 5-story large-block buildings (of the 110 series) just after earthquake of 1995 inNeftegorsk (Sakhalin island).
The main causes of building’s collapseslack of girds between wall blocks and floor slabs between themselves and lack of girds providing space interaction bearing walls and floor disks. Such buildings weren’t designed for construction in seismic conditions.
In such large-block building (of the 110 series), that was redesigned to small flats for singles and small families (on the base of winning concurs project by author) and build in 1964 in Moscow he lives by this time in one of small flat with 3 women (wife and 2 cats) like orthodox Muslim, but without numerous children.
Thank goodness! There didn’t strong earthquake in Moscow. Author would be himself buried in communal graves byearthquake. Then nobody would be condemned.
Besides earthquakesstern tests for buildings are accidents and terrorist acts, which happen often and often latest time.
There are some photos aftereffects of accident and terrorist actsoccurred in Moscowlatest time.
Photos 19-21. Failure 9-story blocks of flats with bearing brick walls and precast floor slabs as a result of gas explosion in 1999 in Moscow (Scherbakovskaia Str.)
The main causes of building’s Failurewere low horizontal load-carrying capacity of brickwork, lack of girds between floor slabs and girds providing space interaction bearing walls and floor disks.
Photos 22 & 23. Failure sections of 9-story large panel building with load bearing precast reinforced concrete framing of first story as a result of act of terrorism in 1999 in Moscow (Gurianova Str.)
The main causes of building’s collapsewere defective bearing structural system (like “colossus with feet of clay*) and lack of girds between wall panels and floor slabs for providing space interaction building bearing system
In spite of numerous of earthquake, accidents and terrorist acts victims there were continue constructing buildings with none or not enough resisting bearing systems because of absents “back-coupling” in form USSR and today Russia (absents of designers and builders personal responsibility andstate officials personal interests). At the same time those and others, as a rule, are not enough professionally prepared, but enough resisting from below - by victims lawlessness, from above – by top managementcynicism.
Unfortunately, the saying: "An Englishman's house is his castle" cannot be said of all houses even in England, as proved by the chain collapse of part of a multistory large-panel block of flats caused by a gas explosion more then 40 years ago in London. This incident, which gave rise to sharp controversy, was investigated in detail byspecialists and served as a spur to the elaboration and implementation of structural measures aimed at preventing the progressive failure of buildings due to the local failure of their load-bearing members. Both before and after this incident however, a number of buildings collapsed in the former Soviet Union and today’s Russian Federation as a result of gas explosions, melting of frozen mortar, use of poor-quality materials and elements, uneven foundation settlings, fires and diversions.
Moreover the public was not, as a rule, given neither objective information on the causes of the disasters, nor an expert analysis of these causes, and the "traces" would disappear into the earth together with the remains of the buildings and victims.
The most severe material damage and are caused by building failure in earthquakes, against which neither "developing" nor "developed" countries are insured, as proven recently by the disastrous consequences of major earthquakes in Russia, the USA, Japan, China, Italy, Turkey and some other countries. But “developing" countriespass ahead of "developed" ones quantitativelyof human losses, and at the same time the former USSR and today’s Russia takes up one of the “honorary” first pleases among them (the first please takes China).
Apparently, the Russian proverb: "Not until he hears the thunder will the muzhik cross himself” - is applicable not only to Russia. However, inthis country the muzhik goes no further than to rely on the national attitude: "Let's hope" that next time the thunder strikes, if he has not had time to cross himself, he will not find himself buried in the rubble of his own "castle".
In addition to naturally earthquakes the cause of construction destructions is “human element”. It may bi household gas explosions, acts of terrorism (the moist destructive with a lot of victims – in New-York 11 September 2001) as well as mistakes of designers and construction defects.
By the way, the more inhuman is society, the more become apparent “human element”.
“Human element” is reduced with developing of society.
Unfortunately it isn’t possibility to build foolproof walls between developed and undeveloped persons and Governments.
But it is possibilities to reduce probability of terrorism acts as well as accidents und heaviness of there consequences.
There are shown below some photo of partly destroyed houses in Moscow, made like “espionage” shots(because of absence spatial permission to photograph destructions).
Incidentally, author has large stage of such “espionage” - more 50 years for photographing “prohibited objects” in Moscow from 14 (from 1948, when all objects in the USSR were being “secret”). But then (while “dictatorship”) for mine “espionage” were only light-trucked my films (and cud shoot). Now (while “democracy”) for such “espionage” I can be imprison, like some other scientists.
Bearing system with “flexible” precast reinforced concrete framing of first stories seems extremely not resistant, especially agents earthquakes and explosions, what didn’t prevent to defend quantity of doctor’s thesis and to construct great number of such buildings in seismically active regions of former USSR. Thousands inhabitants of this buildings didn’t suspect of danger to became a victims of groundless ambitions some of architects, designers, scientists and builders.
The yearly losses brought about by these disasters amount roughly to $4 billion, costing as many as 250,000 human lives, while altogether ten times as many people fall victim in one way or another. Approximately 30% of the overall losses are represented by building collapse and subsequent economic losses. According to non-official sources, over 3 million people were killed and 540,000 hard victim in the USSR and Russia from 1962 to 1992.
The total losses were estimated at about $20 billion. However a high percentage of the victims and economic losses were attributable to building failure and deformation as a result of unsafe load-bearing structures. Moreover thedevastating consequences of accidents and earthquakes have tended to increase recently.
Thus, in the space of a mere three years, over 2,000 people were killed in earthquakes on Shikotan and Sakhalin islands in 1994 and 1995 respectively, and as a result of gas explosions in blocks of flats in 1996 in Svetogorsk, Kaspiysk and Priozersk.
The fact that more of these cases are being reported bears witness ofcourse to the greater freedom of information in Russia, and to the wakening of Nature's evil forces, but also to the weakening of the State's concern to ensure citizens' safety.
Unfortunately, the State is not currently in a position to finance measures for additional protection of buildings against accident and earthquake failure, nor to supervise the implementation of newly adopted ones. Indeed, the Stateitself is near to collapse, which is potentially far more dangerous for our "castle dwellers".
Once the Government has provided for its own safety, it has barely enough funds left to offer material assistance to earthquake victims and compensation to the relatives of those killed, nor is it in a position to finance the Ministry of Emergency Response (MER), although the latter is permanently kept busy - it is responsible forclearing away the rubble after the collapse of buildings and extracting victims. Because of the lack of financing, the MER cannot be expected to deal with removing the causes of these devastating accidents by taking preventive measures.
The activity of the MER, therefore, is not dissimilar to an involuntary reaction of an organism's galvanized extremities whose brain or central nervous system (the State) has beenswitched off.
Furthermore, 5- and 9-story large-panel buildings’ collapsed in local explosions in 1995 inSvetogorsk, Kaspiysk and Priozersk mainly as a result of weak ties between the panels.
Nonetheless, if the stiffness of the ties is sufficient, large-panel structures can achieve space load-bearing systems in the form of a prismatic cellular enclosure,which better withstands accidents and seismic activity. This was confirmed by several earthquakes and explosions in large-panel buildings recently in Grozniy, where relatively few panel buildings failed as their elements and joints had been designed to withstand forces greater than 8 seismic intensity scale(on MSK system), whereas the absence of seismic-resistant ties caused a 9-story large-panel building in Kaspiysk, located in a zone of 8 scale, to collapse in an explosion. Although anti-seismic design is compulsory for buildings located in seismic regions, it is merely recommended that buildings located in non-seismic regions should be designed to withstand progressive failure from accidents. Evidently, the authors of Russian building codes were not fully aware that "velvet paws hide sharp claws" (in Russian: - “softly to spread, but hardly to sleep”).
Author during past tens years was occupying with development of calculation methods and design principles for providing stability of multi-story housings (mainly large-panel ones) by minimization of earthquakes and accidentsconsequences with minimum expenditure for materials and capitals by taking into account particular qualities of interaction bearing elements conditions at the all bearing system work stage – from beginning (elastic one) to limit (transformation one from multiple indeterminate system in to mechanism).
By now it is accepted a requirement to providing compulsory multi-story housings with defense from progressive failure by extraordinary situations, not only by earthquakes (including for the hay-rise buildings in Moscow) and as a result of accidents, thatlead to local destructions load-carrying systems (but meanwhile - only in Moscow for housings above 2 stories).
At that there are some problems of determination accepted seismic intensity scale zones and localization of virtualdestructions zones to calculate defense housings from progressive failureby accidents consequences.
Russian seismic intensity scaleMSK(from VII to IX scales of XII)
Unengineered structures, including small adobe and unreinforced masonry buildings
Partial to total collapse
Brick bearing-wall systems with wooden
Moderate to heavy damage
Brick bearing-wall systems with precast reinforced concrete (RC) floors, three to five stories, pre-1957
Slight to moderate damage
Heavy damage to partial collapse
Brick bearing-wall systems with precast RC floors, some seismic detailing, post-1957
No damage to slight damage
Moderate to heavy damage
Heavy damage to partial collapse
Precast RC frames with welded joints and brick infill walls, four to nine stories
Moderate to heavy damage
Heavy damage to partial collapse
Precast RC large-panel systems with dry or wet joints
No damage to slight damage
Slight to moderate damage
According to this table in Leninakan was seismicity – MSK IX- for 9-stories frame-panel buildings and less than MSK VII – for 9-stories large-panel buildings.
The devastating consequences of a series of major earthquakes in zones classified under the previous building codes as "earthquake-free regions" or as "areas of low seismicity", led to a revision of seismic zoning. Seismic areas were extended and the design seismicity in the Caucasus, Siberia and the Far East of Russia was increased. Consequently, the problem was how to improve the earthquake resistance of existing buildings and of buildings under construction in these regions, while the problem of research and financing remained unsolved.
To be cited in Russia MSK system of seismic intensity scale (see Table 1 above),based on damage level,seems don’t enough objective and correct,because of there dependence from quality structure design and execution.
Energy magnitude degree of seismic activity in Richter scale seems to be more correct then MSK scale. But change-over from MSK scale to Richter scale in Russia requires carrying out a lot of investigations and working up normative documents.
Moreover even observing code requirements does not always guarantee the safety of a building. Eccentric wall layout, miscalculated thermal deformation, poor manufacturing and installation techniques, irrationally placed service openings (ventilation shafts, electric canalizations) can dramatically reduce seismic resistance.
Since it is impossible to eliminate the risk natural disasters and accidents of technicalorigin present for buildings and to predict them with accuracy the severity of their consequences must be reduced as far as possible. Only a professional and responsible approach to the design of a building can guarantee maximal safety for people and equipment. This is particularly important in the design of typical projects, since reproduction of errors can cause not only massive unwarranted material expenses, but also severe consequences in the event of an accident or earthquakes.
A building, just as a living organism, can only exist within a specific framework of internal and external conditions. The more skillfully and professionally constructed a building, the longer it’s life-span and more safety being in it. Both a building and an organism must be able to function in spite of various unfavorable natural and artificial influences. The characteristics, intensity and duration of external influences cannot usually be forecasted with precision, but their limits can be calculated methodically using statistics and probabilities.
Because the forces exerted on buildings are unpredictable, and the response of the structure to these forces may be very complex, the safety of the residents is dependant upon the professionalism and sense of responsibility of the designers and builders, as well as on their ability to approach the building as a single organism whose functioning is determined by the coordination between all its organs.
The design of multistory bearing-wall buildings and especially large-panel buildings with a complex irregular heterogeneous multiple static indefinable spatial load-bearing system require very clever designing, since their response to accidents and seismic action is determined by the size and shape of the building in plan andelevation, by the position of the bearing-walls and openings in them, by the type of joints and ties, and also by the particular interaction between each member.
Unfortunately, typical construction projects in Russia, even in complicated conditions, are usually developed eclectically, with little collaboration between architects, designers, technicians and equipment engineers, which often results in the mass cloning of typical monsters, some time with an innate immunodeficiency to accident and seismic effects. For exception of this, architects and engineers should work as a united team. Architects however are seldom inclined to heed the voice of engineers"from beneath". More often they listen to the voice "from below". Alack, not from the Main Creator, whose voice can hear only genuine talent, but from government officials, who prefer to waste genuine talents.
”Perestroika” (rebuilding) of ends 80-s in the USSR release architects from the government officials pressure (and some time – from necessity to adhere requirements for providing buildings safety and personal responsibility), that allow them to show there talents, exist often only in their luxuriant imagination. Especially, after transfer from mass prefabricated urban house-building to mass monolithic construction, that allowed them to break loose from Procrustean bed of typical industrialized construction hard frames to free creation of individual buildings.
Sometimes architects become into arch-sculptors or even painter-abstractionists, don’t taking into consideration of baffling complexity to calculate, design and build such “installations” as well as to reside in them. But “Beauty requires victims”. However human life is too expensive price to be paid for it. Meanwhile such beauty installations are inclined to change into terrible abstract sculpture from concrete flinders and bones.
Examples of that sort of “installations” formtypes you can see below on pictures by Vadim Rakovsky (of 14 years) from jackets of magazine “Architecture of the USSR” 1990.
Pictures 1 & 2. “Installations”of inhabited complexesin form of “free architecture” by Vadim Rakovsky.
I hope, at present Vadim Rakovsky,went stage of puberty whose erotic imagines reflected in his projects in the form of “architect luxuries”. Becoming adult, he creates less original but more trustworthy objects,like shown bellow. (21-stories monolithic buildings constructed in Pavshinskaia Poima near Moscow).
Photo 24. 21-stories monolithic buildings constructed in Pavshinskaia Poima near Moscow.
May bethese buildings are fetuses by Vadim Rakovsky erotic imagines and they themselves are pregnant next similar fetuses. By the way, on these buildings now erected “architect luxuries” (right one) like on Vadim Rakovsky’s buildings on picture 1 & 2. It was problem to erect these “architect luxuries” (like some times in our life). These “architect luxuries” mast symbolize parts of masts above yachts’ sails (on architect’s idea).
It is possible these buildings’ architecture will stimulate rise of tenant’s birth-rate (to what call as our government).
Unfortunately I was forced to realize these “masterpiece of modern architecture” (being the main constructor of design institute). Like constructor I proposed to utilization these top erected masts like levering bridge between neighbor buildings for saving tenant’s by fire. So much by fire helicopter will not be able to approach to helicopter platform through smog. But “free artists-architects” as a roll rejected my utilitarian suggestions, although I attempted persuasion them more think about post accident buildings’ architecture and about tenants’ safety. “Houses are built to live and not to look on”.
Because as a roll they don’t now how do houses safety, I prefer to get myself in architecture, remembering that an experience testifies “Littleóknowledge is a dangerous thing”.
Fortunately far from all such “installations” are realized.
But there are many other architects, who create his “installations” for self-assertion to the prejudice of dwellings safety and conveniences. Some of them are realized, and not only in Russia. Some already are collapsed. Some wait the same fate. But their dwellings don’t know that.
May be it is good? “Many knowledge is many sorrows”.’
There’ some original buildings in modern world architecture. Examples of very original buildings’ architecture are creations by F. Gery. Taking in consideration of complicity designing such buildings, he takes prays for such buildings’ projects so many as to construct them.
In our country our businessmen pay for designing and constructing no less original buildings like for ordinary ones. These conduct to reduce quality of designing and construct such buildings and to raise their accidents dangerous.
By the whey there is paradox that in our country in comparison with another civilized country by more less pay for designing and construct residential buildings and more less their quality there are more match their prizes.
For past tense from beginning of the ”Perestroika” Russia has rid himself of some illusions but has preserved the aspiration to leave behind “bourgeois”, imitating their forms and coping their technical achievements, including in building constructions. In result we have examples of tastelessness raised on unprecedented high level.
Now “new Russians” or fast became rich new Russian “bourgeois” put up their money in building expensive constructions for selling them more expensive, don’t taking enough care of their safety.
Tendency to rise lately number of buildings stories in Russia, induced by rise earth price in city and great power ambitions of officials, new “bourgeois”and architects, often without sufficient engineering grounds and without taking real conditions into consideration reduce to increase of their collapses danger and consequences heaviness.
Since there isn’t possibility to improve situation it remains to perceive all with humor.
Unfortunately Earthquakes and terrorists aren’t with humor (and as a roll – our bureaucrats too).
For examples of architectonic humor - two pictures by Igor Meglicky are shown below.
Pictures 3 & 4.Igor Meglicky. High tower buildings in “real conditions of Russia” (from magazine “Russian Life”¹9, August, 2007).
Tall buildings like shown on the Pictures are examples of architect’s imaginations, which realization fraught with catastrophic consequences by earthquake. Like two of them (left) built in Qualalumpur (with “bridge” between them, that are able to cause their mutual blows by earthquake) and two like another (right) built in Leninakan (with bearing frame and stiffening core by patent of brooders Saackian) that were collapsed by earthquake 1988 in Armenia. Many such buildings, erected by lift-slab method in Yerevan, wait their fate.
Author opposed construction those buildings types in his appears and publications. But creators of such work of art where (and remain) “Themselves with moustaches”.
Any building may be exposed to accidents causing local failure of isolated load-bearing elements, only it should not lead to the progressive failure of the entirebuilding. Unfortunately, Russia numbers dozens of such cases - even outside earthquakes. Frame type buildings are prone to failure during construction because resistance to failure is not provided during assembly. Brick and large-panel structures are likely to fail just after completion, mainly because of freshly- frozen mortar melting. Buildings as a whole are subject to failure during their operation owing to defects in the load-bearing elements, uneven settling or foundation sliding, gas explosions or other accidents.
Building failure can occur as a result of deformations amplifying over a relativelylong period of time, such as soil protruding from beneath the foundations or uneven settling. This type of failure is not usually answerable for human victims. On the other hand, chain failure usually occurs too quickly for residents to be evacuated and can account for numerous victims.
Building failure from accidents usually originates from an unfortunate combination of factors - firstly, those that fail to ensure sufficient resistance of the load-bearing structure to progressive failure. To avoid these measures should be taken, if a member fails, to ensure the redistribution of forces generated by the structure's own mass and by the design loads of the load-bearing system. This however requires a great deal of knowledge and skills. Moreover restrictions must often be imposed on the layout. Hence preventive measures are seldom taken, creating the premises for building collapse due to failure of individual members. The third type of factor includes the characteristics, intensity and location of accidents that cause one or several elements to be excluded from the load-bearing system (depending on the structural system and layout).
Unfortunately, in spite of accidents causing building failure and their increased likelihood in modern Russia which is saturated with emergency situations, mass construction continues without preventive measures against progressive failure-threatening more, and worse, disasters. The consequences of major earthquakes on buildings are even more alarming.
A considerable part of the Russian Federation is located in seismic zones (the Northern Caucasus, parts of Siberia and the Far East), with a population of approximately 20 million, for whom dwellings must obviously be provided. A number of severe earthquakes in the former USSR which claimed numerous human lives brought to light defects in the load-bearing systems of various types of buildings and accentuated the problem of how to make them more earthquake-resistant. As a rule, the requirements for earthquake-resistance of large-panel structures are the same as those for resistance to accident failure. A close study of the design project of a 9-story large-panel building, which partly collapsed following an explosion in Kaspiysk, located in a 8 MSK scalezone, does not reveal so much the high professionalism of the assumed terrorist bombers as the designers' poor professionalism, who ignored the seismicity of the area and consequently failed to take appropriate measures, which would have prevented failure not only from that particular explosion, but also from potential earthquakes.
It is extremely difficult to combine earthquake-resistant design in seismic regions with the operational and aesthetic properties expected of a building in normal conditions. Since designers and builders are responsible for the safety of people and equipment in the building in an earthquake, they should have a highly professional attitude.
According to SNIP 11-7-81 which establishes additional design parameters characterizing the strength of the load-bearing members and the design seismicity (3 recurrence rates for earthquakes and 3 soil types each with different seismic properties), it was discovered that the design seismicity of regions of 7, 8 & 9MSK scaleshould be characterized by 27 design conditions instead of 3. This complicated the serial design of buildings, necessitating revision and correction of current projects. In order to simplify the problem, the author proposed to introduce non-dimensional coefficients accumulating all variable parameters affecting the rate of seismic action and the strength of the bearing members, and the generalized dynamic characteristics of the buildings, by grouping them into the zones of their serial project. (“Æèëèùíîåñòðîèòåëüñòâî” (“House-Building”) No. 5, 1983). Because of the revision of seismic zoning maps, projects had to be corrected since new seismic regions were brought to light whilst existing zones were extended and their design seismicity was extended from 1 to 3 MSK scales.Moreover, engineers began to worry about how to make existing buildings earthquake resistant since their seismic efforts had been multiplied from 2 to 6. Their concern was aggravated by the question of technical difficulties and material expenditure.
In order to settle these problems, in 1989 the author worked out several systems (which were partly put into application in Armenia) for reinforcing buildings with loggias, balconies and mansards so as to create a horizontal and vertical reinforced concrete bracing. In some cases the loggias had to be lined with seismic-bearing lattice panels. This system enables the reinforcement work to be carried out without evacuating residents. Moreover, it provides increased living area and improves the operational and architectural properties of the buildings.
These systems, proposed by the author, were used in 1990 for the reinforcement of non earthquake-proof 5-story large-panel buildings of the 4570-73/75 series in seismic regions. Here too the evacuation of residents was not required.
For the new generation of large-panel buildings, the author worked out a reinforcement system consisting of special metallic links and autonomous reinforcement (Patent of the Russian Federation No. 4826460). It enabled 5-story buildings of the 101 series (designed for construction in normal non seismic conditions) to be erected in 7 & 8 MSK scale regions without any changes of there elements. Experiments in the Far East, near Nakhodka, consisting of a dynamic force equal to an earthquake of 9 MSK scalegenerated by a powerful vibration machine on one of the buildings using this reinforcement system, showed not only that the system was sufficiently earthquake resistant, but also that the plastic redistribution of forces beyond the elastic properties of the structure should indeed by taken into consideration, as suggested by the author.
Bearing-wall structures with walls of wood, natural stone, adobe, brick and cast or precast concrete panels and blocks are commonly used in mass construction in seismic areas, as are frame type and mixed structures with wooden, metallic or reinforced concrete frames and various infill materials. Such a variety of buildings can however be dangerous for the inhabitants. As the saying goes, "cheapest is the dearest", especially as far as seismic research and project expertise goes. "Saving" on design can result in substantial financial losses or worse still, in countless human deaths. We shall now try to give a general picture of the structural systems of buildings erected in seismic zones of the former USSR. The most common structures used for mass and individual construction consisted of buildings no higher than 3 story’s made from adobe or brick, boards or logs, or with a load-bearing wooden frame and wooden panels, clay or adobe infill. As a rule, no particular anti-seismic measures were taken. The most earthquake-resistant of these structures appear to be wooden houses made from logs or boards and frame type paneled buildings, by virtue of the high elastic and plastic pliability of their load-bearing structure in earthquakes. However the durability and refractoriness of such buildings is usually low and they are unsuitable for large towns, owing to their insufficient stability - which does not permit the highly-priced urban territory to be used in a cost-effective way.
The least earthquake-resistant of low-rise buildings are those with asymmetrical adobe walls and heavy adobe floors and roofs. This type of structure is common mainly in Central Asia. Their earthquake-resistance can be increased slightly by bracing the walls with wooden framework.
As for low-rise brick buildings, their earthquake-resistance depends on the layout and on the quality of the masonry, i.e. on the mortar/brick adhesion. As a rule, masonry has recently begun to ignore the requirements of technology, and consequently fails to ensure adhesion at the mortar seams. Therefore, the reaction to seismic forces depends, to a great extent, on the friction forces at the horizontal seams and vertical bonds of the brickwork.
The prestigious "cottages" which have been springing up everywhere in the past few years are frequently built without the involvement of professional specialists, hence the gross nonobservance of earthquake-resistance requirements both during analysis of wall positioning and calculation of the bearing capacity. Using heavy reinforced-concrete slabs for the floors and roofs bears tremendous risks of earthquake damage.
Also, the new building codes now require the external walls to have increased thermal resistance - this means either making them thicker, or resorting to brickwork with built-in insulation. Both alternatives aggravate the problem of earthquake-resistance - in the first case because the increased mass of the structure generates inert seismic forces, in the second case because there is a risk that the outer layer of brickwork should break away during an earthquake.
Low-rise buildings built with precast hollow concrete blocks are made more earthquake-resistant by filling in the cavities to form a "hidden frame". The effectiveness of this frame depends on the quality of the reinforcement and concreting, and on adhesion between the blocks. Small prefabricated blocks, as opposed to bricks, enable to reduce the mass of the walls and increase thermal insulation. However, it is worth noting that this deteriorates the conditions for filling in the horizontal seams with mortar and weakens the vertical sections of the walls, owing to the cavities in the blocks and the vertical seams, which reduce their earthquake-resistance.
The low-story structures that show most promise for seismic regions are light frame type systems with infill of structural plywood, plastics, metal, wire-fabric reinforced concrete or fibrous concrete. These systems are very popular abroad, but to introduce them to Russia would require first that an adequate manufacturing infrastructure be developed.
Medium-rise buildings (up to 5 stories) usually have brick or large-panel load-bearing walls. Brick walls can be reinforced with a "hidden frame" consisting of a steel frame and by filling in the horizontal and vertical gaps. The effectiveness of this system is depends on the quality of the work.
It is not advisable to use brick walls for medium-rise buildings in seismic conditions, since forces in them are amplified by defaults in the masonry such as mentioned above, which is likely to cause structural damage or failure. The efficiency of brick wall reinforcement by means of a monolithic reinforced-concrete frame depends largely on weather conditions and on the industrial culture. If the bricklaying is inaccurate then instead of strengthening, the walls actually slacken following failure of the vertical bonds of the brickwork, in particular at the intersections of the walls.
The most typical causes of failure in low- and medium-rise brick buildings (in addition to those mentioned above) are as follows:
• For shops located at street level, substituting the brick walls by a precast reinforced- concrete frame. This considerably reduces the general capability of the structure to withstand horizontal seismic forces owing to the risk of failure of the lower and upper joints designed to restrain the columns. The joints act as hinges and consequently the whole system turns into a kinematics mechanism, causing column shear, deteriorating the work of the brick walls of the overlying story’s and reducing the dissipating properties of the foundations;
• Asymmetrical slackening of brick walls on the ground floor because of apertures in them, which leads to torsion of the building layout, a dangerous concentration of forces in the stiffest sections between the apertures, and "drooping" of the walls of overlying story’s;
• Weak ties between floor slabs, which act as horizontal disks that may slacken at staircase emplacements causing them to collapse in an earthquake;
• Slackening of the external longitudinal walls caused by large apertures
(particularly when continuous balconies are built along the facade), which can cause failure of the internal longitudinal walls and especially of weakly loaded floors;
• Slackening of marginal walls caused by large apertures (when there are marginal balconies) - this usually occurs together with the slackening of floor disks due to staircases, and results in torsion and subsequent failure of the marginal sections in relation to the building layout;
• Poor anchorage or weak ties between the floors and monolithic reinforced-concrete beams skirting the outer walls;
• Low resistance of window and door lintels in brick to lateral forces, hindering interaction of the sections between the apertures which is indispensable for withstanding seismic forces.
The greatest earthquake-resistance for medium m-rise buildings is provided by frameless large-panel structures, especially those with numerous inner and outer lateral and longitudinal load-bearing walls, and floor slabs leaning onto them around the perimeter, forming load-bearing systems in the form of closed multiple-chambered shells with two and more symmetrical axes (a square, a cross, a trefoil, a polyhedron or a circle), thus guaranteeing equilibrium of the structure irrespective of the direction of the seismic forces.
In comparison with brick walls, large-panel walls offer a smaller mass and a higher resistance to horizontal seismic forces, and are also more weather-proof. In addition, they can guarantee a large degree of spatial interaction of all the members of the load-bearing system in the event of an earthquake. Moreover, it is considerably more time and labor-intensiveness to build from panels than from bricks.
The drawback of large-panel structures is the inevitable "stiffness" of their layout, caused by the limited variety of standard elements, and the complexity of readjusting the panels for enlargement or modification. Moreover, to develop new series of large-panel buildings involves considerable expenditure for the construction of production space and for manufacturing, setting up and running new equipment. Meanwhile Russia's huge and powerful large-panel building infrastructure is under-exploited, increasing energy expenditure and overhead expenses and thus turning large-panel construction, once the most cost-effective building system, into the most uneconomical. Russia lacks cheap council housing, which is greatly needed but can only be erected on an industrial basis, but the State is not in the position to finance all the existing construction combines.
The few private clients who are actually solvent prefer to invest in the select and hygienic brick "cottages", which, although not so economical (considering the construction and operation costs), correspond better to the requirements and taste of their owners. Another fashionable investment lies in the prestigious multi-story frame type buildings with brick infill. As for the possibly insufficient earthquake-resistance of these buildings, the owners are evidently not too worried about it, since as a rule they are adventurous and optimistic people (features without which they would never be independent). Such materially and morally emancipated people will never let themselves be put at their own expense into serial reinforced-concrete boxes in large-panel buildings (unless it's free of charge or they are sentenced to it, which would be even less likely than an earthquake).
The layout of large-block buildings, which are sometimes erected in the seismic zones of the Russian Federation, is subject to even more rigid regulation. Although a stiff block in itself has comparatively good earthquake resistance, it is not so of load-bearing systems composed of blocks, which are not as safe as large-panel systems in terms of earthquake resistance. This is because it is impossible to fix the blocks together with high precision, which is indispensable for continuous support at the perimeter of the walls. However in the case of partial block support that fails to provide cohesion between the blocks (if they are not concreted together), there is risk of collapse if vertical and horizontal loads are accidentally applied, causing shear and torsion of the blocks at their horizontal and vertical planes.
Buildings with longitudinal external and internal load-bearing walls made of large concrete blocks ensure relatively good layout flexibility. These structures are widely used, mainly in non-seismic regions. Weak ties connecting wall blocks, floor slabs and paneled elements of transverse stiffness diaphragms are responsible for the low earthquake-resistance of large-block buildings - this was confirmed by the results of the 1995 earthquake in Networks, formerly classified as a 7 magnitude zone and built mainly with five-story large-block buildings that collapsed, costing about two thousand lives.
Multistory buildings (up to 9 story) and high-rise buildings (more than 9) were originally built merely with a metal or reinforced concrete load-bearing frame and brick, small block or panel walls. They can only withstand earthquakes by means of rigid frame joints or by special braces or diaphragm walls and shear cores. Frame type structures allow relatively great freedom of layout because of the small cross-sections of the members, especially if a flat-slab system is used. In these constructions, the fact that the function of load-bearing is separate to that of enclosure makes it easier to use efficient materials in order to reduce the mass of the building and consequently the intensity of seismic forces. The relatively high flexibility of frame type structures compared to bearing-wall structures also reduces the inert forces likely to affect the structure, particularly if the ground has a spectrum of predominantly short- wave of seismic vibrations. Frame type structures have a simpler and more regular general layout than bearing-wall structures, which simplifies the static and dynamic analysis. It should be noted however that the design seismic force (with a spectrum of short-wave vibrations) is several dozen times less likely to diminish on a frame type building than the corresponding moments of resistance of each member, as a rule, of the rectangular transversal cross-section in comparison with the resistance moments of the load-bearing members of bearing-wall systems, which as a rule have elaborate composite transversal cross-sections. This generates considerable tension from seismic forces on frame type structures. Moreover, the lesser ability of frame type structures for inelastic redistribution of forces in the event of failure of individual members and ties makes them less safe than non frame type buildings.
However, this factor is not taken into consideration in modern methods of building design. Evidently, until methods for the analysis of buildings to seismic conditions come to include the consequences of inelastic deformation and local failure of members and ties on the work of the load- bearing systems, this factor could be represented by an additional safety coefficient, whose value would be established by expert calculation.
During the last few decades, multistory frameless large-panel buildings were built all over the country, even in highly seismic regions, where they used to be forbidden, or restricted, by Soviet building codes.
The traditional image of large-panel buildings as "houses of cards" is gradually being replaced by the conviction that they can actually be built to withstand earthquakes -his is shown by the increase of the maximum amount of story’s permitted by Russian codes for large-panel buildings in seismic regions.
Thus, at the end of the 1960s, the first experimental 9-story large-panel buildings (of the E-101/109 and E-147 series) were erected in areas of Tashkent and Alma-Ata, rated at seismic intensity scaleIX MSK(or about magnitude 8 earthquake) in spite of the existing height limitation to 5 stories. Author worked out main architectural (constructively-planning scheme) and structural solutions for first large panel buildings for construction in high seismicity areas of the USSR, that contributed leading theoretical and experimental works, followed by a more specific analysis of the load-bearing systems focusing on the behavior of panel structures in their extreme state (partial foundation uplift, uncovering of horizontal joints, inelastic behavior and possible failure of individual elements and ties). This work also included more efficient structural and layout designs, as well as advanced engineering solutions for bearing members and butt joints. The viability of these analyses and solutions was confirmed by laboratory and full-scale tests and by actual dwelling construction, which showed the stability and durability of the structures, even during real earthquakes, enabling the projects to pass from the status of experimental to standard.
Project series where worked out by “Moscow Central Research and Design Institute of Dwellings” (“«CNIIEP zhilishcha»”) and France Firm “CAMU”.
All experimental works were conduct on experimental base of “«CNIIEP zhilishcha»”.
Thanks to elaboration of new effective structural solutions "houses of cards" changed to “castls”, that was proved by researches and real earthquakes.
However until now height restrictions on large-panel buildings stipulated by SNiP 11-7-81 (Russian Building Norms) are unjustified and "discriminating" (there are no such restrictions on monolithic and frame type buildings) at any rate when a panel building is designed irreproachably.
However, since «bad laws are badly obeyed" in Russia, life continuous.
Previous of large-panel buildings for hay seismic active areas and justice of proceeding was confirmed most visibly by destructive earthquake of 1988 in Armenia (see Photo 11-17).
Unfortunately, bad obedience to bad laws does not always prove satisfaction, what was proved by collapses of 9-story frame-panel buildingsin Leninakan.
But bad obedience of good laws almost always lead to bad result, what was proved by collapses 5-story buildings in Spitak (see Photo 6-10).
Obviously, designing and constructing residential houses, especially multistory buildings in high seismic active areas, may be trusted only to specialists. Otherwise we have pictures like below, were 9-story frame-panel buildings has disintegrated just as house of cards, while competently projected 9-story large-panel buildings didn’t have any damages.
Since the end of 60-sfirst large-panel buildings higher then 5-story (with principal structures, worked by author) were erected in 9 MKS scale zones in Tashkent (of the E-101-109 series,worked up by Russian – “«CNIIEP zhilishcha»”the France Firm “CAMU”)and in Alma-Ata (of the E-147&158 series)on project, with Kazakhstan – Large-panelHouse-building factory of Alma-Ata, “Kazgorproekt” and “Alma-Atagiprogor” (Design Institutes of Alma-Ata buildings).
The first 8-story building of the E-147 series build in Alma-Ata (Photos 24 - 26) was tested by powerful vibration machine in 1972 by «CNIIEP zhilishcha» (Russia) and “Kazakhpromstroyproekt” (“KazakhstanScientific and Design Institute of industrial buildings”).
The building has endured without serious damages accelerative forces mounted to high seismicity, corresponding to magnitude about 8 earthquakes.
Since the end of 70-s multistory large panel buildings of the series 2T-SP(based on theE-101-109 series) and 148 series (based on theE-147 and 158 series) are erected in high seismicity areas(9 MKS scale) of Tashkent (project worked out by the Russian – “«CNIIEP zhilishcha»” and Uzbek –“TashZNIIEP”(“Tashkent Scientific and Design Institute of Dwelling”).
Consequently, using latticed earthquake-bearing panels as enclosures for loggia in these buildings as proposed by the author (patent of the USSR No. 317766) is unlikely to work if structures such as horizontal platform joints with concentrated stiff metal projections are used, since they are unreliable in seismic conditions owing to their poor resistance to shear.
Utilization of one of constructional solutions – grating loggia external bearing panels ( patent of the USSR # 317766 ) that take part in perceiving seismic forces and provide promotion of space interaction of bearing element systems multistory residential buildings in Tashkent and Alma-Ata saved more than $ 160 millions for decrease concrete and reinforce in comparison with buildings of the series 2T-SP(based on theE-101-109 series) constructed in Tashkent, when grating loggia external panels aren’t bearing. For this I became in 1985 20000 rubles (about $ 30000 then) after 5 years judging with Kazakhstan Government. But they were “privatized” in 1991 by government’s Savings-Bank of the USSR that became auctioneering Savings-Bank of Russia.
Some photos of large-panel buildings, construct in sections of MSKIX seismicity in Alma-Ata and Tashkent are shown below.
Photos 25 – 27. Process of assembling and fragments of fronts 8 & 9-story large-panel buildings (of Ý-147 & 158 series) with the seismic-bearing grilled loggia enclosure panels (patent of the USSR No. 317766) in Alma-Ata (author worked out main architectural (constructively-planning scheme) and structural solutions for buildings).
Photo 28. The first building of the series E-101 in Photo 29. The first building of the series 148 in
Tashkentwith external partly bearing wall panels. Tashkent with bearing external and grilled loggia enclo- sure panels
Photos+ 30 – 32.9-story large-panel buildings of the series 2T-SP(based on theE-101-109 series) with the nonbearing grilled loggia enclosure panels Tashkent(author worked out structural solutions for buildings, accept grilled loggia enclosure panels).
As for monolithic buildings, they are no less sensitive to weather conditions than brick buildings and require more sophisticated manufacturing techniques. The horizontal seams created in the floor slabs by breaks in the concreting process can cause "sliding seams" and make part of the walls insensitive to shearing forces in stretched areas if the seams uncover, resulting in a concentration of normal and shearing forces in the "compression zones" which are likely to collapse as a result, especially when the compression zones contain platforms formed by sections between apertures that are orthogonal to the direction of the seismic forces. This is characteristic of monolithic and panel buildings with internal and external load-bearing longitudinal and transversal walls, and creates the need for special structural measures to deal with shear forces at the horizontal seams when these latter are uncovered. Ignoring this factor is one of the main reasons for earthquake failure of multistory frame type buildings with weakly loaded monolithic or prefabricated "shear cores".
However, manufacturing panel members to butt joints designed to provide safe interaction across the entire length of the assembly, including the areas of detachment, reduces building labor input and the dependence of the quality of the load-bearing material upon random factors, partly because the manufacture and assembly of elements is more easily controlled. This makes large-panel buildings more earthquake resistant than monolithic buildings.
Horizontal platform joints were developed by the author for external and internal wall panels with shear ties placed across their entire length to assure panel interaction across the entire length of the assembly, including the areas of detachment. This system was tested for the first time at the beginning of the 1970s in 9-story panel buildings of the 148 series, erected in areas of Tashkent rated at magnitude 9, but was not used in 9-story 2T-SP buildings in Tashkent before the end of the 1980s. In full-scale tests these joints proved practically indestructible when subjected to a number of normal and shear forces owing to the "cage effect". Moreover they automatically assure forced precision of member assembly by reducing the possibility of members being displaced in relation to one another, whilst increasing the precision of vertical member assembly by excluding accumulation in elevation of dimension errors in the butt ends of floor slabs, which subsequently improves the operational and aesthetic qualities of the building owing to more accurate observance of the gap between the panels. Moreover, it has become possible to assemble members at subzero temperatures using dry mortar which is subsequently wetted. Panel buildings with this type of joints designed to provide panel interaction, including the areas of detachment, work as monolithic structures to an even greater extent than monolithic buildings themselves. The latter are transformed by earthquakes into "prefabricated" structures because of seam uncovering, which is still not taken into account during engineering analysis and construction.
Although frame type structures have more flexible layout possibilities than panel constructions, their earthquake resistance and cost-effectiveness are inferior, which is attributable mainly to the following points:
• The ground floor columns risk losing stability in the event of lateral ground displacement combined with powerful vertical forces from the upper floor;
• the frame junctions of reinforced-concrete frames risk failure under alternating normal and shear stress, forming hinges that turn the load-bearing system into a mechanism;
• reinforced concrete columns risk shear at their fixation to the foundations if the ground floor has stiff wall infill and weak shear ties in the horizontal joints;• the seismic load is transmitted irregularly to the foundations under diaphragm walls and shear cores, which often leads to foundation failure and tilting of the diaphragm walls and shear cores;• reinforced-concrete columns adjoining shear walls suffer uneven loading, which can account for vertical tensile forces that increase the risk of column shear under lateral forces at the level of the horizontal seams of the diaphragm walls;
• the frame junctions of steel frames risk failure as a result of brittle shear of welded seams (in welded joints) or subsequent shear of rivets (in riveted joints), because the stiffness of the frame infill is frequently ignored, so are the design stiffness of the load-bearing systems and the design seismic forces likely to affect the building;
• the relatively small cross-sections of the members of the reinforced-concrete frame causes increased metal consumption;
The construction of frame type buildings requires a comparatively high labor input as a result ofthe low availability of prefabricated elements and the great length of seams to be filled on-site at the fixation of the wall infill to the frame members.
Wallenclosures have poor operational qualities because of seam uncovering at their fixation onto the frame members owing to the shrinkage of non-loaded wall infill and frame deformation. Although framelesslarge-panel buildings have more restricted layout possibilities than frame type buildings, they can provide better earthquake resistance and at a lower cost, by virtue of the following features of their load-bearing systems:
• Thevertical load-bearing members are comparatively evenly loaded, have a developed cross-sectional area and are attached by means of fairly stiff butt joints and lintels to the spatial load- bearing system, which protects them from tilting and torsion, particularly if they are enclosed by a load-bearing system (for instance seismic-bearing latticed panels as loggia enclosures on the basis of patent of the USSR No. 317766);
• the design diagram of the load-bearing structures of panel buildings possesses a higher degree of static in definability and is capable of redistributing forces if several members or ties collapse or fail to work, which alleviates the hazard of progressive failure;
• friction forces in the horizontal joints of wall panels play an important role in the perception of seismic forces, which helps the earthquake-resistant panels to depend less on weather conditions and on the "human factor" (i.e. the skills and conscientiousness of the structural engineers and builders),
• the load-bearing systems of panel buildings possess greater dispersive properties;
owing to the significant damping role of the ground which acts as one block with the foundations, partial foundation uplift, uncovering of the horizontal seams of panel walls, and the inelastic behavior of elements and their butt joints which absorbs energy by "dry friction" at the joints, modifies the dynamic parameters of the building so as to reduce resonance development and consequently inert seismic forces, and leads to a more uniform distribution of forces between the horizontal and vertical elements and ties;
• The maximum forces and stresses are reduced in panel members owing to the large area of their lateral cross-sections. This allows concrete of lesser quality to be used and reduces metal consumption in comparison with frame type buildings;
• buildinglabor input is reduced by using precast infill elements;
• usingprecast vertical joints and compressing the horizontal joints enhances the operational qualities of the infill.
The merits of large-panel buildings refer to the possibilities of their structural system, which requires quality design with optimal coordination between architectural and structural solutions, and also a creative approach, since it is not governed by rivetsregulation.
In addition to the conventional structural systems in seismic building practices, "mixed" systems were sometimes used, such as frame/brick, panel/frame, panel/large block, panel/tie, frame/core, etc. Each of these systems combines the merits and shortcomings of both components. Nonetheless, in several cases combining structural systems gives rise to new features, both positive and negative. Thus, when the load-bearing structural system of panel buildings incorporates seismic-bearing latticed panels as loggia enclosures (on the basis of patent of the USSR No. 317766), the load-bearing system is transformed into a panel/tie system in the form of a closed prismatic envelope which provides optimal conditions for the interaction of all the members of the system irrespective of the direction of seismic forces. This system was applied in 9- and 16-story panel buildings (of the E-147, 148, 158 series etc.) erected on sites of magnitude 7 and 8 in Alma Ata, Tashkent, Bishkek and other towns of former Soviet republics in Central Asia, where it helped reduce greatly the cost and materials consumption of the load-bearing structures both aboveground and underground, owing to even distribution and stress reduction in the elements as well as in the foundations and ground. Tests carried out by the “CN1IEP Zhilishcha” (Moscow Central Scientific Institute of Dwelling) in 1972 in Alma-Ata, in which the first experimental 8-story large-panel building of the E-147 series was exposed to horizontal dynamic forces close to a magnitude 8 design seismicity (the forces were produced by means of a powerful vibrating machine) showed that it was sufficiently earthquake resistant and that the seismic-bearing grilled panels acting as loggia’s balustrades were highly efficient when subjected to dynamic loads both across the length of the building (which verified the active role played by the external longitudinal walls in the work of the load-bearing system), and across its width (verifying the deformation of the building as a stiff box).
Combining the stiff box of a multistory panel building with a "flexible" reinforced concrete frame at street level proved not only inefficient, but dangerous, although its efficiency as a "passive" anti-seismic system was supposed to have scientific grounds according to a number of publications (including doctorate theses) which served as references for the construction of multistory buildings in seismic regions of the former USSR in the 1960s. A building on such "flexible" legs offers insufficient resistance to seismic action - this was confirmed by full-scale tests and by real earthquakes. Indeed it is obvious enough that in this "seismic protection" system, the disadvantages of a full reinforced concrete frame, as outlined above, are aggravated by extra risk of column shear both at the column fixation onto the panel box and in elevation at places where lateral waves running up the "flexible" column and bouncing back off the stiff panel box meet.
At the beginning of the 1970s there was a plan for fifty 16-story buildings of this type to be erected in areas of Baku of magnitude 8. Thank God (or Allah?) that following my comments on this "protection system" and these projects in particular, the construction was cancelled. After the collapse of several buildings of the same type in earthquakes in other regions they were classified as non earthquake resistant.
Not everyone, however, is convinced that they are, fortunately, the transition from experimental to mass construction of large-panel buildings on "swiveling" bearings composed of reinforced-concrete supports with spherical ends, which was planned in the mid 1970s, was postponed, since large displacement risks converting the system from a "passive" seismic protection to an "active" falling system, like an "inverted pendulum". In 3 experimental 9-story buildings erected in Sevastopol "disconnecting ties" and spring shock-absorbers were to be installed to serve as horizontal displacement limiters, and sand bins as vibration dampers for "dry" friction. The safety of this earthquake resistant system is too costly and unreliable, despite the variety and complexity of structural measures designed for it. Its main drawbacks are as follows:
• the panel box is point supported merely by the intersections of the load-bearing walls, which leads to a dangerous concentration of normal and shearing forces and causes the door lintels to "hang";
• Large horizontal seismic forces are likely to be transmitted to the non earthquake resistant panel box through the displacement limiters and the vibration dampers;
• the reinforced-concrete supports risk falling out if a contact fault occurs with the panel box, causing failure of the vertical load designed to prevent them falling (this may be the result of uneven foundation settling or transmission of a vertical seismic wave).
Unfortunately, it was not possible to prevent the construction of 16-story large-panel buildings in Sochi with frame type ground floors and priestesses shear cores, despite numerous remarks I addressed to “TbilZNIIEP” (“Tbilisi Scientific Institute of Dwelling”), where the projects were developed. The main concept justifying the considerable reduction of the design seismic load on the buildings (despite the fact that this could turn them into rubble in an earthquake) did not include shear ties and neglected the friction forces in the horizontal joints of the wall panels. This is permitted by Russian building codes, but only as a safety factor. It seemed to the project authors a good enough reason to ignore the stiffness of the panel structure which was consequently unnecessarily reduced, as were the design seismic forces on the shear cores. The buildings therefore have serious structural defects and are insufficiently earthquake resistant even in magnitude 6 zones, to which Sochi belonged when the buildings were erected in the mid 1980s. When in 1995 Sochi's design seismicity was raised to magnitude 8, the buildings underwent reinforcement following a new system developed by A.N. Kurzanov, doctor of technical sciences at the “SibZNIIEP” (SiberianScientific Institute of Dwelling). The system was a "passive" earthquake protection (shock-absorber resistant technique) consisting of prismatic reinforced-concrete supports installed at ground level which are not connected to the underlying foundations nor to the panel structures of the first floor. This system is even more dangerous than that used in Sevastopol consisting of swiveling reinforced-concrete supports with spherical ends, because if the ends of the supports are flat, rotation can result in overstrain along their edges (if seismic forces pass through the axes) or at their corners (if the shock occurs under the corners and tends towards the axes) under the action of sign-variable vertical and horizontal forces and bending moments. This may cause shear fracture in the concrete across the perimeter of the column edges, forming hinges at their connections to the foundations and to the panel box and turning the load-bearing system into a kinematics mechanism. Even before this happens, the columns themselves risk collapsing if the vertical load designed to keep them from falling disappears following a contact fault with the panel box, which can result from uneven ground deformation or transmission of a vertical seismic force through the ground and the box of the building. Retrofitting a load-bearing structure with this seismic resistant system as a safety precaution is unlikely to save the building from a magnitude 8 quake, since once the shear core and the building frame fail, inertial motion continues, causing the supports to tilt. Moreover, the first destructive shock may be followed by aftershocks, with a "fatal outcome" for the building and its inhabitants.
"Passive" seismic resistant systems in the form of "sliding belts" are no less dangerous, especially in the platform joints between the panel walls and floor slabs, as they can cause the slabs to slide off the supports and provoke inadmissible reciprocal vertical displacement from the plane of the wall panels in an earthquake. This "seismic protection" system was developed by “LenZNIIEP” (Leningrad ScientificInstitute of Dwelling).It is used in the absence of shear joints and consists of "dry" horizontal platform joints with elastic linings along the upper edges of the wall panels, and "dry" vertical joints for the internal and external walls, where the role of the shear joints is performed by the edges of the floor slabs which are built into the joints, and additional joints formed by the flanges of the wall panels built into the vertical joints, that are automatically brought into action in an earthquake. Despite my comments relative to this system, it is being applied for the construction of 9-story large-panel buildings (series 122 and 178) in regions of high seismicity in Siberia. I fear that the effort to "kill two birds with one stone", i.e. to reduce the seismic load whilst simplifying the structure in view of low temperatures, could end in the death of countless "guinea-pigs" who happen to be indoors during an earthquake. In an earthquake, the load-bearing panels risk coming apart as a result of shear at the edges of the floor slabs in the vertical joints, whereby the joints designed to "switch on automatically" fail to do so because of too many non- adjustable and uncontrollable gaps between the connected surfaces of the ties. Floor slabs also run the risk of sliding out from the walls as a result of excessive friction in the horizontal joints where there are no shear ties. The legitimacy of the author's comments was confirmed by full-scale tests performed by the "«CNIIEP zhilishcha»" in 1988, in which one of the experimental 9-story panel buildings of the 122/E-164 series in Neriungri was subjected to a powerful vibrator.
"Active" earthquake resistance based on special dampers generating dynamic, antiphase or mixed phase forces in comparison with the phases of the maximal seismic forces exerted on buildings is also unreliable. These dampers have systems enabling them to "switch on" and operate automatically in an earthquake. They are however too complex and unreliable given the conditions for construction and operation of buildings in Russia. Moreover, dampers increase a building's mass, which, in the event of a seismic shock, could amplify horizontal shearing forces in the load-bearing structures of the foundations and the lower story’s. It also seems that in bearing-wall systems, which are the most widely used load-bearing systems for multistorybuildings, the development of resonance effects is unlikely if the periods of the building's own vibrations coincide with the those of the seismic forces, particularly considering the development of inelastic deformations in the building and ground.
I conducted research on the effect of static and dynamic horizontal forces on multistorylarge panel buildings, and subsequently carried out a number of large-scale tests to confirm the theory. They showed that when a load-bearing system is subjected to loads near the ultimate load, its stiffness can decrease several times over. In addition, a significant redistribution of forces between members occurs as a result of their uneven alterations in stiffness (mainly because of the uncovering of horizontal joints) and partial foundation uplift.
The formation of cracks in the ground surrounding 9-story large-panel buildings that I noticed after an earthquake in Leninakan (Kumayri) is a manifestation of non-elastic ground deformation. However, they also bear witness to the fact that the foundations merged with the ground, attracting the seismic vibrations as one block and so acting as a seismic damper. This is obviously what gave survivors the impression that the earthquake waves had "avoided" the large-panel buildings, destructing all other frame type structures and stone buildings on their path.
The discussion conducted recently in the press (notably in "Æèëèùíîåñòðîèòåëüñòâî") by S.B. Smirnov, doctor of technical sciences and professor at the Moscow State University of Civil Engineering, concerning the improper application of the resonance theory to earthquake engineering as currently specified in thebuilding codes is not without grounds and deserves consideration. Indeed, the nature of earthquakes is extremely complex and can manifest itself in waves, shocks, or as chaotically mixed action, hence the intricate and crucial issue of how to provide safety for the large population of Russia's seismic regions. However, there are several of his comments and proposals with which it is impossible to agree. Undoubtedly, the earthquake-resistant theory and earthquake-proof building design methods used as the basis for building codes, as well as engineering solutions for the structural load-bearing systems and building members require perfection and constant updating, only it should be done progressively, not in the revolutionary fashion proposed by Mr. Smirnov, who ignores outright the dynamics of earthquakes, which he defines as a simple shock system necessitating a radical revision of the design methods and principles of earthquake resistant construction.
In 1966 in Tashkent I "had the pleasure" of experiencing myself earthquakes of various nature and intensity and was able to observe the response of buildings both indoors and out. Thus, I was at the top floor of a four-story brick building in the centre of Tashkent, when I felt a powerful shock and the subsequent vibrations of the building from an earthquake with a fairly shallow epicenter near the city centre. The brickwork was of sufficient quality and strengthened with reinforced-concrete braces and the layout was planned to code, so that the damage was relatively small (formation of cracks and floor displacement), despite the insufficient seismic-upsetting seams which divided the building into compartment-like blocks. During the same period, the after-shock of another severe earthquake in Iran reached Tashkent in the form of high-amplitude long-wave harmonic vibrations, which gave the awesome impression that the earth was being metamorphosed into a giant serpent waking up (incidentally, this could be an explanation for various legends on the animate nature of the Earth). Fortunately, this experience was not my last, since at the time of the earthquake I was standing outside an unsafe building, waiting for the keys to be brought to me so that I could go inside to inspect the damage previous earthquakes had caused to the roof, which had in fact collapsed under the effect of seismic waves originating from far away. The roof however did not live to hear my verdict, because the metal girders slid out of their supports.
This personal experience with earthquakes induced me to take a more critical attitude towards several newly adopted or proposed artificial "passive" and "active" anti-seismic systems, including the "passive" system put forward by Mr. Smirnov designed to avoid the consequences of horizontal shocks by means of a massive reinforced-concrete slab resting on "supple" metal legs. This system is inefficient and too material-consuming since it involves reinforcing the metal supports to enable them to withstand heavy vertical loads and horizontal foundation displacement. Reinforcing the supports means stiffening them, which amplifies the impact of horizontal seismic forces on them. Moreover it increases not only the consumption of metal and concrete, but also the building's mass owing to the addition of reinforced- concrete damping slabs, which increases the inert seismic forces. The result is a vicious circle. As for Mr. Smirnov's suggestion to design buildings to seismic shocks with accelerations tens of thousand times that of free fall acceleration "g" (9,8 m/s2), it is indeed improbable. As a rule, the peak horizontal acceleration transmitted in an earthquake by the ground to a building does not exceed the free fall accelerations owing to the constraint of the ultimate value of the horizontal force transmitted to it by the friction forces between the foundations and the ground (which do not exceedthe weight of the building if the friction coefficient is less than one) and by lateral pressure of the ground on the part of the building below ground (which does not exceed the ultimate value of the passive pressure of the made ground). Since the ground, as a rule, offers relatively low resistance to horizontal forces, one should expect it to collapse around the building (this in particular was observed in Leninakan), or the building to suffer displacement at the horizontal seams of monolithic or panel walls when they are not provided with special shear ties (here also with accelerations not exceeding "g") - horizontal shear is not expected and until now has not been established anywhere. Building displacement accelerations exceeding "0" can occur where a building is rigidly fixed in rocky or frozen grounds. In rocky ground moreover, the speed of seismic wave transmission is relatively high, which also tends to increase the accelerations transmitted to the buildings by shocks. However the current codes covering buildings located on rocky ground establish the design seismicity at 1 magnitude point less, evidently because part of the seismic energy is absorbed by the ground (if the epicenter of the earthquake is situated outside the rocky area). In frame type buildings, the friction forces between the foundations and the ground and the lateral thrust from the ground may be enough to cause column shear. It is more likely however for reinforced- concrete columns to fail at their fixation because of cracking caused by bending moments combined with the failure of compression zones from normal and shearing forces.
Mr. Smirnov's doubts as to the viability of the seismic parameters measured by pendulum-type inertia sensors are well founded in the case of displacement of the sensors inside the buildings or in direct proximity to them, since they then record not only the vibration amplitudes and periods of the foundations, but those of the buildings themselves, and also their own dynamic parameters.
The limited volume of this article and of the author's knowledge does not permit a critical analysis of the entire range of possible building response to earthquakes, nor a study of all the feasible earthquake resistant systems. That should be the subject of research conducted by seismologists, geophysicists, theoreticians, inventors and other specialists.
Inventions such as artificial shock-absorbing bases, flexible structural members and elastic and plastic ties were used in ancient constructions and sacred edifices and successfully survived the trial of time and earthquakes. Â.A. Kirikov's "Selected pages of the history of earthquake-resistant construction" ("Mir" (“World”) publications, 1993) offers an interesting overview and analysis of various "passive" systems for the seismic protection of edifices. However it is not possible to agree with all the proposed systems, nor is it always possible to apply the most effective ones to modern mass construction - not so much because the construction of temples was assisted by the gods, nor because of the relationship of the engineers to their own creation and work, but mainly because of the ratio between the buildings, their load-bearing members and the ground displacement parameters. Indeed, soil displacement is insignificant in relation to the dimensions of the load-bearing members of ancient sacred edifices. Their dimensions may even seem excessive compared to those of modern edifices and prone to loss of stability or likely to slide off the supports as a result. In modern multi-story buildings vertical loading often exceeds by far that of historical constructions, while the stiffness of the material of the load-bearing structure (concrete) is usually inferior to that of materials used in the past for load-bearing members (natural stone). Besides, economical considerations (which were hardly a preoccupation for slave- owners or under the feudal system) often hinder the construction of a building on massive artificial bearings. As for the sense of responsibility towards one's creation and work, it used to be fortified by the fear of both divine punishment and death sentence (the death penalty was used in such cases according to the Laws of King Hammurabi). Nowadays, in the event of damage or failure of a building, its designers and builders as a rule only feel a slight shudder, if they are aware of the tragic fate of their creation at all, particularly if it was part of a collective, serial project.
I must confess that I also am an inventor of "passive" earthquake resistant systems (which however have not yet been implemented for industrial purposes), among which foundation isolators with hydraulic dampers for buildings located on normal or uneven ground (patent of the USSR No. 327296). However my concern for people's safety prevents me from implementing the system without preliminarily conducting thorough research and testing each structural item, for which as yet I have not the resources. This risk of implementing "active" and "passive" earthquake resistant systems combined with my lack of resources for research and testing forced me to direct my practical work towards the problems posed by mass earthquake-resistant contraction, which I try to solve by upgrading the conventional structural systems already in use. Research I conducted on panel buildings subjected to heavy horizontal loads showed that buildings are naturally "passive" earthquake resistant systems. Seismic action can therefore generate inelastic or virtually inelastic deformations in the buildings and their foundations, lowering several times over their reduction stiffness, and consequently their vibration periods, causing the seismic forces to decrease. Appropriate ties and members increase the amount of inelastic deformations which increases the earthquake-resistance of the buildings by more reliable and economical means compared to artificial "passive" and "active" seismic protective systems.
Experimental buildings were erected and tested in order to verify the performance of several "passive" and "active" systems, although the defects in most of the systems could have been identified during preliminary expertise, especially as the nature of artificial earthquakes can be substantially different to that of natural earthquakes, which is a particularly important factor for artificial seismoresistant systems. However, the buildings being "experimental" sometimes meant that their inhabitants were too. This does not at all mean that we should stop searching for new efficient earthquake-resistant structures - it simply stresses the need for a more responsible approach, as the victims of this kind of experiment are not mere guinea pigs, mice or even the project authors.
Unfortunately, these experimental buildings are not the only threat to human lives in an earthquake or an accident. Conventional buildings often fail to meet safety requirements also, which is even more dangerous because of their mass reproduction. However the revision, needless to say the modification of the concepts is greatly hindered by the monopolistic character and ensuing conservatism of the institutes responsible for the projects and the factories that manufacture the required items.
A closer look at current projects for the construction of multistory buildings in seismic regions generally shows that the architects, being mostly concerned with theaesthetic appearance of the building and trying to ensure agreeable living conditions for its residents, either ignore or underestimate the working requirements of the load-bearing structures in an earthquake or accident. They forget that the architect should be concerned not so much with how a building will look after the construction, as with how it will look after an accident or an earthquake. That is why when I am working on projects for earthquake-resistant buildings I do not limit myself to their analysis and design - I also work actively on the layout, since the safety and cost-effectiveness of an earthquake-resistant building often depends just as much on its layout as on its structural design. Thus, in the tragic 1988 earthquake in Leninakannot one of the fourteen 9-story large-panel buildings (of the 1A-451 KP series), whose structural concepts and panel joints I designed, were damaged. However a number of 5-story large-panel buildings were seriously damaged in Spitak under virtually identical seismic action, because their layout was unsuitable for earthquake resistance and they had weak panel joints. In Alma-Ataand Tashkent, nine 16-story large-panel buildings were provided with load-bearing architectural elements in the form of latticed panels for loggias enclosures, representing various regular geometrical patterns, which not only gave the buildings a particular "oriental" style but also increased their earthquake resistance. It would be very sensible to retrofit buildings in Armenia with this kind of latticework round the loggias.
Neglecting the shrinkage of multistory large-panel and monolithic buildings due to temperature fluctuations can be extremely dangerous in seismic regions, as seismic forces can cause failure of the members and ties, and hence failure of the load-bearing walls. In normal conditions the members and ties would collapse with subsequent failure of the enclosures and even of individual members and their components (for example, balconies and the outer shell of 3-layered panels of external walls). In order to reduce the likelihood of similar impacts of shrinkage on multistory large-panel buildings in normal and seismic regions, I worked out new foundation structures (patent of the USSR No. 327296), three-layered external panel walls (patent of the USSR No. 226828), seismic bearing latticed panels as loggia enclosures (patent of the USSR No. 317766), panel joints for external walls (patent of the Russian Federation No. 1223774) and loft roofs (patent of the USSR No. 326322), which all allow for shrinkage under temperature fluctuations.
Unfortunately, some of the concept designs proposed for shrinkage compensation need the "thunder" to strike again many times more. The latest 3-layer panel structures for external walls where the layers are held together by means of "stiff' and "flexible" ties risk a "bolt from the blue" at any moment. That is, the outer layers risk falling out owing to failure of the "stiff' ties or because the "flexible" ties stick out from the concrete as a result of temperature fluctuations, humidity or solar radiation.
Alas, buildings continue to be assembled as "kinder surprises". Although the likelihood of a "super-prize" (i.e. a building collapsing in an earthquake) is relatively low, that of a "mini-prize" (i.e. failure of individual members owing to shrinkage) is extremely high, although the consequences are not so catastrophic (at least for the population as a whole, however untrue for the individuals concerned).
Based on these remarks, we shall now focus on the main problems brought about by increasing the resistance of buildings to earthquakes and accidents, and suggest solutions for them.
The first problem involves finding a method to assess a building's resistance to accidents and earthquakes before the actual construction. The method should establish the extent to which the building needs reinforcing as well as the most appropriate concept design to adopt. This problem should be solved by implementing a certification system for buildings that would issue certificates establishing the safety margin of their resistance to earthquakes and accidents, on the basis of the independent State expert review of current projects and inspection of existing buildings, giving priority to seismically active regions. In order to make the collection, processing and access of data on buildings and their structural elements more straightforward and expedient, the data should be computed in unified numerical or alphabetic codes and condensed tables containing, in addition to the nameplate details (address, area, number of inhabitants, project series, designing institution and certifying authority, date of project, construction company and construction period), a description and assessment of the following factors and characteristics of the structural members affecting the stability of the structure:
• shape and size of the building or space between the seismic seams;
• height and number of story’s;
• designmass of the building converted torn;
• structural system;
• foundations structure;
• structureof the vertical load-bearing members;
• floor and roof structure;
• stability and stiffness characteristics of the ties;
• design allowance for resistance to accidents, which should be calculated by comparing the working energy of external forces (i.e. the structure's own weight and useful loads), to that of internal forces (i.e. the resistance of the structure) in accidents of various types with various failure patterns.
For earthquake-resistant buildings the following additional data should be provided:
• dynamic characteristics of the building;
• dispersive properties of the foundations and supporting ground;
• dispersive properties of the load-bearing system;
• ultimate design level of seismic forces on the building (expressed in magnitude on the Richter scale), limited by the load-bearing capacity of the ground, the most loaded members of the load-bearing system or ties;
• ultimate design level of seismic forces on the building, taking into account the possible inelastic behavior and dispersive properties of the ground and load-bearing structure.
The last major characteristic for a building's general earthquake resistance includes design parameters which require clarification by further research. Since the intensity of seismic forces on a building cannot be known in advance, the maximum intensity should be defined by elastic analysis and limited at the ultimate strength in the most stressed member or tie, or by analysis with an arbitrary calculation of inelasticdeformations by means of restricted plastic deformation between the members both in plan and elevation. It is moreover indispensable to construct the members and ties so as to exclude the possibility of failure from lateral forces until they are affected by plastic deformation.
For the strength analysis we recommend that in addition to the accepted safety factors for individual structural elements extra factors be introduced for the safety of the load-bearing system as a whole. They should include the level of static in definability of the system, its capacity to redistribute forces in the case of failure of individual members, the dispersive properties of the ground, the "human factor", weather conditions and possibly other factors.
Each of these factors should be characterized and analyzed separately, and given a qualimetryc assessment in the form of non-dimensional coefficients worked out on the basis of the generalization of design, experimental research and expert survey data. Integrating these coefficients would provide the load-bearing structures with a generalized relative safety characteristic.
For buildings in seismically active regions, this problem cannot be solved without a very close analysis of the soil characteristics. If detailed maps of seismic regions are not available, they should be drawn up from the results of geophysical and geological engineering research. It is also fundamental not to ignore the possible modification of these characteristics because of water-saturation, settling, freezing, etc.
If a building is discovered to be insufficiently earthquake resistant, its load-bearing structure should be reinforced, or the building demolished and rebuilt.
In this case the following steps should be taken:
• increase the earthquake resistance of the building to the required level by applying the most effective structural solutions and carrying out experimental and theoretical research as required;
• assess possible earthquake damage, perform necessary repair work and reinforce insufficiently earthquake resistant structures;
• study the feasibility of rebuilding and modernizing the structure in order to increase its earthquake resistance whilst at the same time improving its aspect and performance, or of demolishing it to replace it with a new structure, according to the requirements and possibilities of the investor.
Computer coding of information on buildings would facilitate the automation of reinforcement design and the cost and feasibility assessment of rebuilding the structure by stating the volume and priority of work to be performed, and would ensure adequate materials selection and control.
In the event of building damage or failure, this would make it easier to track down the author of the faults and thus force the engineers to adopt a more responsible approach and stimulate the professionalism of each participant in the construction process, hence improving the quality of the building and providing safety for its residents.
The fourth problem concerns the protection of buildings under construction from failure in accidents or earthquakes by using more reliable and economical resources.
The problem arises from the fact that neither the designers and builders nor the State authorities take enough interest in achieving high quality standards, safety and cost-effectiveness and have no precise criteria for assessing the safety of a building. Similarly, there is no adequate correlation between the result of the work performed and its remuneration.
By performing expert quality controls on the design and construction of residential buildings in normal and seismic regions of the former Soviet Union, generalizing the results of scientific research and analyzing the consequences of accidents and losses earthquakes, I came to realize that a great many accepted engineering solutions have extremely poor scientific grounds and that there are no serious procedures for independent project expertise and construction supervision. This is likely to be the cause of insufficient earthquake and accident resistance, and brings the threat of particularly disastrous consequences.
In civilized countries with a developed market economy the stimulation to ensure high quality and safety of dwellings is maintained by a system of State and private insurance combined with State control, covering both the client (the resident) and the contractor (the constructor). In Russia it is obvious that until the market economy is in place and functioning properly, State safety control of the load-bearing structures of buildings needs to be reinforced. This requires the participation of highly qualified and conscientious specialists who should be accordingly remunerated for their work - the price of losses from potential accidents and earthquakes is far higher to pay than regular, adequate salaries.
The most expedient way to boost the quality standard of expert reviews and to readjust construction projects to current building codes whilst using the most efficient engineering solutions to their full potential, bearing in mind the monopoly exerted by the large design institutes and construction combines, would be to organize open tenders for all construction projects, which would necessarily involve qualified independent experts.
In the light of the abovementioned, although I see no light in the dark tunnel leading from "developed socialism" to "underdeveloped capitalism" and notwithstanding the fact that such projects are no longer financed by the State, I continue to work out new concepts for load-bearing structures, members and ties and upgrade existing ones not only with the aim of providing increased resistance to accidents and earthquakes, but also better performance and appearance of the buildings, reduced material expenditure and labor costs, whilst using the existing infrastructure of the building industry to its full potential.
To decrease probability of earthquakes and accidents disastrous most effectively into practice (bearing in mind that it should be applied equally to both “the slums” and to “the palaces”, the author as early as 30 years suggests to elaborate the"Universal Architectural-Structural-Technological System" in order to develop the industrial construction of individual and serial types of buildings and ensure protection from failure in the event of accidentsand earthquakes, in the most economical way possible and using to its maximum potential the existing building infrastructure.
The reasons for the expediency of the proposed "Universal System" and some of its architectural concepts are laid out in an article written by the author and published in«Æèëèùíîåñòðîèòåëüñòâî» (“House Building”) Nos. 1&3, 1994. Unfortunately, this article has still notreceived any comments in the press, and no budgetary funds were assigned to the elaboration of the "Universal System", although the idea was approved by the Ministry of Construction of the Russian Federation. Recent attempts in the West to work out unified structural systems focus on "flexible" techniques for manufacturing elements of a single type, or on the standardization of elements within the framework of a single structural system. Our proposed “Universal System", based on the unification of different types of elements, will guarantee their interchangeability and their inter-correspondence. Moreover it will become possible to broaden the diversity of the layout of various purpose buildings and premises and also to create buildings of various shapes (including structures that are non-orthogonal in plan and large-span space structures), thus ensuring increased resistance to accidents and earthquakes. By covering various structural systems, the Universal System will allow the existing industrial construction and equipment infrastructure in Russia to be used with partial alteration of the required equipment.
Meanwhile, powerful though the Russian construction infrastructure may be, it is not being exploited to its full potential and is suffering from old age and "dekulakisation". This is due partly to the lack of State financing of mass construction, and partly to the fact that the industrial structures have beendiscredited as a result of their low operational and aesthetic qualities and tendency to frequent failure in accidents and earthquakes, which is currently increasing in Russia. This article deals precisely with the protection of buildings from failure in accidents and earthquakes, using the concept designs laid out in the “Universal System”, which is a product of the author's theoretical and practical studies.
"Universal System" makes possible the transition from a serial design of "closed" (disparate) structures to a unified "Open Architectural System" for individual and mass construction of various types of residential or office buildings in normal or complex conditions, using various types ofreinforce-concrete unified interchangeable and interconnected standardized modular prefabricated ferroconcrete items, such as linear (frame), plane (panel), and space (large-block) with different combination between them and with brickwork, small blocks and cast-in-place concrete.
The majority of concept designs are based on the most efficient designs (including several of my own), some of structural decisions are certificate of authorships and patents of the USSR und Russia, underwent laboratory and full-scale tests, were approved in experimental and mass construction, and were even tested by real earthquakes.
Optimum unification, interchangeability and interconnect ability of elements irrespective of their sections and position in relation to one another is ensured by standardizing their position in relation to the modular mesh of axial gridlines and modular installation levels on each floor, which is achieved by giving a particular shape to the faces of all elements in order to make them compatible. The degree of stability of the building to various categories of accidents and earthquakes is regulated by means of autonomous reinforcement and weldless joints, and by introducing special stiffness elements. Moreover, the suggested vertical and horizontal butt joints of the load-bearing elements helps avoid displacement across the joints and planes of the elements, which increases both their own stability and the stability of the whole building and reduces the likelihood of progressive failure from accidents and earthquakes. Frame type, panel, block, brick, monolithic and mixed structural systems will possibly be constructed on the basis of the proposed "Universal System" and thus, by virtue of the suggested engineering solutions, possess improved accident and earthquake resistance compared to conventional structures.
Work is currently being performed to enlarge the field of application of the "Universal System" by adding non-orthogonal modular axes to the modular mesh of axial gridlines at any angles (it is desirable multiples of 30 degree), enabling buildings with complex plans to be erected. The plans can be polyhedrons and possess various non-orthogonal fractures if fillers for the floors are introduced in small quantity. Moreover, spatial load-bearing constructions can be created by virtue of the interaction between wall members and floors provided by means of butt joints. They can take the form of enclosures, allowing buildings to be "bridged" with considerable spans without necessarily making the elements thicker or increasing the consumption of metal; they also permit the reconstruction of five-story buildings by adding multistory annexes and superstructures, even without evacuating residents.
Adopting the proposed system would facilitate the automation of building design and instrumentation manufacture. Moreover it would reduce the likelihood of building collapse both in normal and seismic regions in the event of faulty design or construction. It would not exclude further development of individual elements, as the concept design of one element does not entail subsequent modification of all the other elements.
In order to avoid the "posthumous rehabilitation" of precast construction in Russia it is urgent that the government lend support to the development and realization of this "Universal System", since the prefabrication methods for mass urban construction continue to be discredited as a result of the low operational and aesthetic merits of prefabricated buildings and their insufficient protection against accident and earthquake failure.
At the time of unsuccessfully practical realization in the former Soviet Union "Universal System", that promote to increase reliability protection from progressive collapse of buildings by extraordinary situation, the Soviet Union has collapsed progressively himself, as a result of naturally appeared.
However in today’s Russia has remained danger extraordinary situation of buildings progressive collapses and appearance in addition - danger of social progressive collapses, it is disappeared old strong barriers, that over 30 years ego had prevented my immigration to “Historical Native Land”.
Unfortunately, in spite of preservation topicality of my different architectural ideas and structural solutions (including that weren’t published and realized) and conservation creative potential, as well as reservation own strength, it is difficult in my edge (75) to jump over new barriers, appeared in the other side.
But in today’s Russia, like in the former USSSR, in spite of sad experience, “Hinges are right where they started”. As regards to me: - “There's no use crying over spilt milk”.
I thank misses Rachel Vasilchenko and “ABBYY Lingvo 12” for help me translate this article from Russian to English.
I ask your forgiveness for my “Russian English” and numerous grammatical and syntactic mistakes in it.
If more detailed information regarding the "Universal System" or any of its individual concept designs is required for application to concrete building conditions, please contact the author at the following address:
Home: Moscow, 127220, Äîìàøíèé: Ìîñêâà, 127220,
Petrovsko-Razumovskiy proezd, Ïåòðîâñêî-Ðàçóìîâñêèéïðîåçä,
home 8, apt. 14. äîì8, êâ. 14.
Tel.: 8-(495)-613-18-86. Òåë.: 8-(495)-613-18-86.