МУ англ ПГС
.pdfoccur. The foundation is a reinforced casing. On it there stands a three-storey building together with a metal tower 360 m high.
TEXT B. THE USE OF PYRAMIDAL PILES IN BUILDING
Pyramidal piles are a progressive design of piles used in building. These piles have the shape of an enlarged pyramid; they are rammed into the ground, acute end first. Unlike prismatic piles, pyramidal piles pack the soil along the sides while sinking into it, thus enhancing the mechanical quality of the soil, and subsequently conveying the load of the whole side surface upon the packed basis.
Such distinctive feature of the work of prismatic and pyramidal piles in the basis soils ensures the possibility to enhance the bearing capacity of pyramidal piles with respect to prismatic piles by 1.5-2 times.
Pyramidal piles are used in the basis of buildings and constructions for various purposes and designs. They are especially effective when packed soil lies on the upper part of the basis from 3 to 5 deep, while loose soil can lie underneath.
In this case pyramidal piles must work as single piles. When pyramidal piles are arranged in groups and joined by a low foundation raft, the depth of the loose soil should be taken into consideration as well as the number of piles in the group. If the basis is made up of cocked soil along the whole depth, the number of piles in the group is not limited.
The structural design of pyramidal piles is carried out in accordance with the deformations, proceeding from the equality of the work of external and internal forces with due regard for obligatory requirements. The volume of the stabilization zone should not exceed the volume of the consolidation zone while conveying the load to the pile.
TEXT C. GRILLAGE FOUNDATION
Grillage, foundation bed, reinforced concrete footing, as a means of protection, tier, to be encased, to resist, bending, shearing, bond, stress.
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In order to distribute a column load over the foundation bed, steel grillage is occasionally used instead of a reinforced concrete footing. This usually consists of two layers of beams. The beams are encased in concrete not less than 4 in thick as a means of protection, and the lower tier rests upon a bed of concrete to distribute the column load to the foundation bed. Since the grillage beams must be completely encased in concrete, the bearing areas of the grillage foundation and a reinforced concrete footing are practically the same. Therefore, it is usually expedient to use the reinforced concrete footing. In this case the concrete resists lending, shearing, and bond stresses instead of merely being a protecting material for the steel grillage beams.
TEXT D. THE FOUNDATION OF THE OSTANKINO TV TOWER
The reinforced concrete tower of the TV center in Moscow was built latter the design of Nokolai Nikitin. The tower is 535 m high. The 32-thousand- ton tower rests upon a monolithic hoped reinforced concrete foundation 9.5 m wide, 3 m high and 74 m in diameter. In the 10-angled reinforced concrete band of the foundation prestressing was created by means of a system of stressed hooping.
The depth of the foundation is 4.65. It is assumed that it will settle from 3 to 3.5 cm. The stability of the tower has a six fold margin of safety.
The 8th International Soil Mechanics and Foundations Congress recognized N. Nikitin’s idea of building the foundation at the depth of 4.65 m to be a brilliant one.
While the foundation was being built, specialists expressed their concern that the depth was insufficient for such a high tower. Relying on the experience of putting up high-rise structures, specialists suggested a hypothesis stressing the necessity to plant the base of the TV tower on supports resting upon a rock.
Scientists were of the opinion that because of the insignificant depth of the foundation, ground work in its vicinity (the building of collectors, tunnels, metro lines etc.) could result in the loss of earth from under the foundation. The
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specialists who shared this opinion recommended a 40-metre foundation. But N. Nikitin turned down that opinion and proved that his designed tower could stand even without having a foundation. Nikitin’s calculations have been confirmed by life.
The reinforced concrete support of the whole structure is a conical casing which rests upon bankets of the foundation with 10 reinforced concrete “legs”.
The diameter of the lower base of the casing is 60.0 m, being 18 m at the height of 63 m. The upper part of the reinforced concrete bole, beginning at the height of 321 m, is made in the form of a cylinder with an exterior diameter of 8.1 m. The base walls of the tower are 500 mm thick.
In the center of the conical base, resting upon an independent foundation (a round reinforced concrete slab 12 m in diameter and 1 m thick), a reinforced concrete “pocket” 63 m high and 7.5 m in diameter was erected through which run means of communication”. The beam ends of 15 interstorey floors rest upon the “pockets”. The construction (a separate foundations for the two independent structures – the tower and the “pockets” – allows to exert upon the ground different pressure when uneven setting occurs.
Notes
1.monolithic hooped reinforced concrete foundation – монолитный кольцевой железобетонный фундамент.
2.a 10-angled reinforced concrete band of the foundation – десятиугольная железобетонная лента фундамента.
3.a system of stressed hooping – система кольцевой напряженной арматуры.
4.a sixfold margin of safety – шестикратный запас на опрокидывание.
5.to rest upon a rock – опираться на скалу.
6.to result in the loss of earth from under the foundation – приводить к выводу грунта из-под фундамента.
7.to turn down an opinion – отвергать мнение.
8.to be confirmed by life – быть подтвержденным жизнью.
9.a conical casing – коническая оболочка
10.banket (banquette) – насыпь, берма
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11.a leg – опора, стойка
12.a reinforced concrete bole – железобетонный ствол
13.pocket – гнездо, «стакан»
14.to run – зд.: проходить
15.means of communication – средства коммуникации
16.interstorey floors – междуэтажные перекрытия
17.uneven settling – неравномерная осадка
18.to occur – происходить, иметь место
1.Find answers in the text to the following questions:
1.What does the durability of a structure depend on? 2. How were foundations built prior to the beginning of the last century? 3. Can you tell us what kind of foundations is used in the northern regions of our country? 4. Were piles used in ancient times? 5. Do you know anything about the foundation on which Ivan the Great’s bell tower in the Kremlin stands? 6. When was ferro-concrete discovered? 7. Pile boring has found wide application, right? 8. Can piles be made without using building materials? 9. Why is the foundation of the AlmaAta TV tower considered to be quite original?
2.Find in the text nouns corresponding to the following words and translate them into Russian:
to apply, to destroy, durable , to burn, wooden, to begin, to bake, stability, firmness, peculiarity, to shorten, widely, dependent, service, appearance, useful, binding, protection, discovery, filling, development, drill, hard, erection.
3.a) Find in the text the antonyms of the following words and translate them into Russian: the end, to disappear, stable, young, long, the present, down.
b)Find in the text the English equivalents of the following words and word-combinations:
прочность сооружения; до начала прошлого века; устойчивый грунт; ленты из камня и обожженного кирпича; известковый раствор; наши
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предки; топи; свайные фундаменты; в давние времена; круглые бревна; забивать сваи; огромная каменная плита; погружать; оберегать от разрушения; уйти в прошлое; без применения строительных материалов; горелка; затвердевать; землетрясение; железобетонная коробка; буронабивная свая.
4.Render the following sentences in English:
1.Пирамидальные сваи имеют форму усеченной пирамиды, забиваемые в грунт острым концом. 2. Пирамидальные сваи при погружении в грунт производят уплотнение грунта вдоль боковой поверхности, повышая тем самым механические свойства грунта. 3. Отличительные особенности работы пирамидальных свай в грунтах основания обеспечивают возможность повышения несущей способности пирамидальных свай по отношению к призматическим в 1,5-2 раза. 4. Пирамидальные сваи применяются в основании зданий и сооружений различного назначения и конструкции. 5. Особенно эффективно их применять в том случае, когда в верхней части основания на глубине 3-5 м залегают плотные грунты.
6.При кустовом расположении пирамидальных свай, объединенных низким ростверком, учитывается глубина расположения слабого слоя и количество свай в кусте. 7. Если же основание сложено на всю глубину плотными грунтами, то количество свай в кусте не ограничивается.
5.Discussion: Your ideas about the material.
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UNIT 8
TEXT A. FROM THE HISTORY OF WATER SUPPLY.
Water is power not only in the hydraulic sense, but in relation to progress and culture; campaigns as well as fortresses have been lost, projects rendered impracticable and communities have decayed for want of water.
Nature has provided prototypes for most of man’s devices and, just as the streams and rivers anticipated water distribution systems, so tanks, cisterns and reservoirs have their natural counterparts in water-holes and natural pools.
Long after man had found ways and means to organize water supplies, find them where they were hidden and lead them to where he wanted them, streams and pools in their natural state have served as communal water supplies, even in more or less civilized Europe.
Many of the so-called “wells” of medieval Britain, for example, were untouched pools or gushing springs. The same applies of course to a great many “wells of the East” and in old writings the term “well” may not mean a dug well at all but a surface pool adopted as a communal or regular water supply.
The history of conduits or public fountains as communal water supplies starts at least as far back as the 13th century. In the “conduit age” – the centuries immediately following the Middle Ages a water carrier was a common sight.
The 17th century marks the beginning of the new order in communal organization and in relation to water supply, the beginning of large-scale schemes.
All through London’s history until modem times, the question of water supply continued to be a problem. In the 18th century even with the appearance of larger water companies the water supply was far from being satisfactory. It was a usual practice at the time to lay on water for two hours every second day.
At York, before the formation of the present water company in 1846 one half of the city was supplied for 2 hours on Mondays, Wednesdays and Fridays and the other half on Tuesdays, Thursday s and Saturday s, no supply being given on Sundays.
Water drawn from the river Thames was in a state that was offensive to the sight as the intake was found to be only three yards from the outlet of a
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great sewer. As a matter of fact it took 2 outbreaks of cholera to pass a Bill for an improved water supply in the middle of the 19th century.
In spite of the progress made in the field of water supply in many countries, there is much to be done yet. In Asia, Africa, Central and South America outside the great cities, methods are primitive as ever they were; village ponds are still used in Africa and Asia for drinking, washing and bathing and as watering places for cattle, in Madagascar in recent years people have had to carry their water bottles several miles and, as some of them can only do the journey twice a week, they have trained themselves to do with the minimum of water, drinking only on alternate days and never washing during a drought.
In Japan, running water is still a luxury, even in the great cities: the average household has to carry water from a central source, while the villages rely on springs and streams.
The speedy industrialization of our country has also made the problem of water very acute.
TEXT B. PURIFICATION OF WATER SUPPLY.
Water taken from its natural source – the ground lakes of rivers – contains many objectionable elements. It may possess gases of an obnoxious nature, bacteria, mineral elements, mud, and suspended vegetable growths which render it unpalatable. Some of these objectionable materials may be eliminated readily, others require complex treatment.
The obnoxious gases are removed by aerating the water. Some of the mineral elements, such as certain forms of iron, also are removed by this means. The suspended materials require coagulation and settling process, and bacteria are eliminated with the addition of chemicals and sand filtration. The mineral elements which render the water hard must be separated by a chemical process in which the objectionable element is replaced by one that is favorable. A filtration plant may use one or a combination of all of these processes, the water undergoing a complete change as it passes through the plant.
The processes generally employed in making water safe for water supply include coagulation, filtration, and disinfection. Water from some sources must
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be treated also for the removal of color, taste, and odor. Coagulation is commonly effected by adding to the water a salt of aluminum (usually aluminum sulphate) or ferric iron. A precipitate forms and causes a clumping of the bacteria and other foreign particles which then settle out during the several hours of sedimentation; in this way 85% or more of the bacteria and suspended particles can be removed. Activated carbon is sometimes added before sedimentation to remove tastes and odors. In the process of filtration the water is allowed to pass through layers of fine sand to remove remaining germs and particles. Chlorine is commonly used to destroy harmful bacteria persisting in a municipal water supply after the other treatments? Chlorine dioxide has more recently been found effective as a destroyer of bacteria as well as means of removing unwanted tastes and odors. Other means of destroying germs include the use of ozone and of ultraviolet light. Some water supplies are aerated, i.e., exposed to the action of air and sunlight either through sprays or by running over coarse gravel; taste and odor are improved and some germs are destroyed.
TEXT C. WATER SUPPLY.
Water is an important part of nature which surrounds us and of those natural conditions we are changing constantly and ever more intensively: the flora, the soil, the mountains, mineral resources, the deserts, the marshes, the steppes and the taiga.
Water passes through a very interesting natural cycle. The atmosphere which surrounds the earth’s surface contains water which varies in amount in direct proportion to the temperature of its gases.. Water is also evaporated into atmosphere. Atmosphere which has become saturated with water precipitates its moisture when the temperature lowers. This phenomenon is termed rainfall. The moisture falls to the earth and finds its way into a number of reservoirs provided by nature.
Vast depressions in the earth are filled with water through the medium of natural water sources such as rivers, lakes, etc. over the earth’s surface. These bodies of water are classified as inland lakes and are excellent sources of water.
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Sometimes the rainfall finds its way into the soil and forms water bodies at various levels because of the impervious nature of the under soil. Often a water body deep in the soil consists of a sand or gravel stratum which connects or empties into the basin of an inland lake and provides a splendid source of water supply through the medium of a drilled well.
Man uses water for domestic and sanitary purposes and returns it to the source through sewage disposal system. Industry likewise replaces water diverted to its use. Hence the cycle is completed but it is of prime importance that the supply be protected against pollution, for if it fouls no one can predict how disastrous may be the results.
An adequate supply of pure, wholesome and palatable water is essential to the maintenance of high standards of health and to provide the convenience modern society demands. In some localities water is available in unlimited quantities and converting it to use is not a difficult problem. This is especially true of towns situated on large inland lakes or rivers. On the other hand there are cities where geographical location requires elaborate systems of water supply, and to provide a satisfactory supply of water in these localities becomes a large engineering task.
The importance of a sufficient supply of water for domestic and industrial purpose has long been a deciding factor in the location cities. The earliest settlers realized this need and took advantage of natural water sources by establishing colonies in close proximity to them
Water may be taken from any sources of water for human consumption after it has undergone a preliminary treatment to assure its purity. As man’s communities grew in population, the demand for water increased and the need for protection of the source of water supply against the possibility of contamination became evident. Progress and civilization have called for elaborate and various systems and methods of water treatment.
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TEXT D. THE CONTINUOUS COUNTERCURRENT FILTRATION
SYSTEM
The continuous countercurrent filtration system includes chemical precipitation and coagulation directly followed by filtration through a filter bed. The basic principle involved is continuous countercurrent filtration through a moving sand bed.
Chemicals are added directly to the influent wastewater line. Precipitation and coagulation occur in the head tank. The dosage of chemicals can be varied depending on the nature of the waste to be treated and the quality of effluent desired.
The filter medium, which could be other than sand, is contained in a tubular shell (called a bed) and is driven in one direction while the wastewater being treated passes through the filter bed in the opposite direction. The filtering action occurs through the depth of the bed as well as at its face. Filtered water flows out of the bed through discharge screens located on the side of the bed. The sand and solids filtered out of the water are pushed by a hydraulic diaphragm toward the head tank countercurrent to the flow of water. The solids are removed from the face of the filter bed by a mechanical face cutter. After the diaphragm pushes the bed forward, it relaxes, thus allowing clean sand to fall into the space vacated by the relaxing diaphragm. The frequency with which the sand push-face cutting cycle occurs is varied to optimize flow rate and effluent quality and is controlled automatically by the level in the head tank.
The sludge-sand mixture mechanically removed from the filtering face falls down into the hopper bottom of the head tank. This mixture is transferred to a washing column for cleaning. The clean sand is then returned by gravity to the hopper. The removal and washing of the sand may be intermittent or continuous. Final washing of the sand is accomplished by means of filtered effluent. Because the sand is removed, cleaned, and then returned to the system, the filtration process is not interrupted for backwashing as it is in conventional practice. The waste wash water flows into a settling tank where the sludge is
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