Structural foamed glass block are designed to fill ceilings, and for making interior partitions in buildings and rooms, to ensure heat and sound insulation.
Concrete is perhaps the most widely spread building material used nowadays. Concrete is an artificial stone, made by thoroughly mixing such natural ingredients or aggregates as cement, sand and gravel or broken stone together with sufficient water to produce a mixture of the proper consistency. It has many valuable properties. It sets under water, can be poured into moulds so as to get almost any desirable form, and together with steel in reinforced concrete it has very high strength, and also resists fire. Prestressed concrete is most widely used at present while prefabricated blocks are employed on vast scale for skeleton structures.
2. Прочитайте и переведите выделенные в тексте слова и выражения. 3. Прочитайте и определите, какие предложения относятся к а) дереву, б) кирпичу, в) пластику г) бетону. Предложения переведите на русский язык.
1. This material is provided by different kinds of trees.
Synthetic resins are the main raw material for production of this material.
In can be hollow, porous and lightweight.
It is employed as a building material in the form of boards.
It is lighter and not subject to corrosion.
It is made of cement, sand and gravel or broken stone together with water.
It sets under the water.
It can be used for decorative purposes.
It can be easier machined.
10. It may be made of clay by moulding and baking in kilns.
11. Together with steel it has very high strength.
12. It is laid in place with the help of mortar.
13. It possesses a high resistance to chemical action.
14. Prefabricated blocks are made of it and they are employed for skeleton structures.
4. Закончите предложения о металле, слоистом пластике и пеностекле в соответствии с текстом. Предложения переведите.
1. Aluminum in the form of various alloys is highly valued for …
2. Steel finds its use in…
3. Laminate is a strong material manufacture from…
4. It resists severe weather conditions for more than ten years …
5. It is used for …
6. Foamed glass is made of …
7. It is widely use in prefabricated house building for …
1. Прочитайте и переведите данный текст. Вспомните, как переводятся выделенные слова и выражения.
TEXT 2. THE PROPERTIES OF CONCRETE
Concrete must be hard, strong, durable, dense, non-porous, fire-resisting and economical.
Concrete has proved to be durable when made of good materials, well mixed, and properly cured. Failures can be found in concrete work, but the trouble is usually caused by poor material, faulty foundations, and lack of knowledge of the properties or poor workmanship. For example some cements will give better results in sea water than others. This fact had to be established by experience and experiments.
It is more difficult to secure durable reinforced concrete than mass concrete. This is due to the reinforcing steel and the additional water required to make the concrete flow around the steel bars. When moisture reaches the steel, it will rust and expansion caused by the rust will crack the concrete, resulting in unsightly structure and necessary repairs. In all structures exposed to the weather the reinforcing steel must be carefully placed and well secured so that it cannot be displaced while concreting. Small wires will soon cause rust spots on the surface of the concrete if they are exposed.
Concrete, to be durable, must be made of good materials, uniform in quality, mixed with a minimum of water, and properly placed and protected while curing. Concrete exposed to sea water and the rise and fall of water levels, especially in cold climates where ice forms on the structures, requires special attention in the selection of the cement, aggregates, mixing, placing and curing.
With the use of dense aggregates the proportions which will produce the densest products are generally those which contain the maximum amount of coarse aggregate and still contain enough fine aggregate to produce a smooth surface. With porous aggregates used in the production of light weight units, the amount of material in the mix passing a 50-mesh sieve is generally limited and in addition more of the coarse aggregate is used to produce a unit of less density and lower weight. This is generally desirable for light weight units except where fire resistance or watertightness are important.
The strength of plain concrete depends upon the quality of the cement, the strength and character of the aggregate, the quantity of cement in a unit of volume, and the density of the concrete. Other things being equal the strongest concrete is that containing the largest amount of cement in a given volume of concrete, the strength of the concrete varying directly as the amount of cement. The strength of concrete also depends upon the methods used in mixing, upon the care taken in measuring the ingredients, and in the mixing and placing the concrete. Concrete exposed to the air hardens more rapidly than protected concrete. The setting of cement is a chemical change brought about by the addition of water to the cement, the strength increasing very rapidly the first few days, after which the mixture slowly hardens and increases in strength.
Concrete has poor elastic and tensional properties, but it strong in compression. Its tensile strength is only one-tenth of its compressive strength. The compressive strength of plain concrete varies between wide limits, depending upon the cement, the proportions of cement and aggregates, and the methods of mixing, and placing and the age.
2. Закончите следующие предложения в соответствии с текстом.
Переведите полученные предложения.
1. Concrete must be …
2. Failure in concrete work are caused by …
3. It is more difficult to protect reinforced concrete than mass concrete because:
a) it will …
the expansion caused by the rust will ….
the result of this is …
4. In all structures exposed to the weather the reinforcing steel must be …
5. Concrete to be durable must be made …
6. More of the coarse aggregate is used to produce …
7. Light weight units can’t be used where fire resistance and …
8. The strength of plain concrete depends upon …
Concrete exposed to the air hardens more rapidly than …
Concrete has poor … but it is strong in …
3. Переведите предложения, обращая внимание на выделенные грамматические формы.
Concrete has proved to be durable when made of good materials.
This fact has to be established by experience and experiments.
Reinforcing steel in concrete can rust resulting in an unsightly structure and necessary repairs.
Concrete to be durable must be protected while curing.
The densest products are those, which contain maximum amount of coarse aggregate and still contain enough fine aggregate to produce a smooth surface.
The strongest concrete is thatcontaining the largest amount of cement in a given volume of concrete, the strength of concrete varying directly as the amount of cement.
The setting of cement is a chemical change, the strength increasing very rapidly the first few days.
The compressive strength of plain concrete varies depending upon the cement.
IX. MY SPECIALITY I am a second year student of the Building Institute of the Tyumen State University of Architecture and Civil Engineering. It is one of the largest higher educational establishments in our town. The Civil Engineering Institute was founded in 1971. Our Institute trains civil engineers in the following specialities: “Industrial and Civil Construction”, “Manufacture of the Building Structures”, “Management of Real Estate”, “Heating and Gas Supply”, “Road Engineering”, "City Construction” and “Water Supply”. During the years of activity the Institute has trained many highly-qualified engineers. Such specialists are in great demand nowadays. There are the day-time, and extra-mural departments. Those who combine studies with their work are trained at the extra-mural departments. The whole process of studying deals with mastering new construction methods and progressive technology of production of building structures and materials. The junior students are taught mathematics, physics, a foreign language (English/German/French), chemistry, philosophy, computer processing of information. We attend lectures, do laboratory work and tests. We have quite a number of well-equipped laboratories at our disposal. Mastering one of the foreign languages enables us to read foreign literature and learn about the latest scientific and technical achievements abroad. The senior students study special engineering subjects such as Strength of Materials, Theoretical Mechanics, Building Materials, Geodesy, Architecture, etc. The fourth-year students combine their studies with their research work. We write course papers and graduation theses on the scientific problems of our research work. Many highly - qualified teachers work at the departments of our Institute, some of them have candidate's degrees and scientific ranks. In summer the students of our faculty, besides vacation, have their practical hours in order to have a clear idea of what our speciality means. According to the academic plan the fourth -year students are sent to work at different plants and construction sites, where they learn to employ in practice the knowledge they gained at the University. During practice the students master the job of a civil engineer and at the same time collect materials for their diploma papers. The final and most important period in the students’ life is the defence of the graduation work in the presence of the State Examining Board. All the graduates get work according to their speciality. We shall work at building material factories, on construction sites, at design and research institutions and laboratories. Besides, we are provided with everything necessary for a scientific career entering a post-graduate course. In a word we have a wide range of job opportunities.
1. Ответьте на следующие вопросы, используя выражения:
I suppose... I think... It seems to me... As far as I know (remember)...
I believe... As a rule... Usually... Besides...
1 What University do you study at? 2 What Institute do you belong to? 3 When was it founded? 4 Are you a second-year student? 5 What specialists does the Building Institute train? 6. Why do you want to become a civil engineer ? 7 What subjects is the academic program composed of? 8 Why do our students study foreign languages ? 9 What does the course of studies end with? 10 What problems do the students deal with in their course papers and graduation theses? 11 Where do our graduates work ? 12 In what way can graduates continue their study?
2. Вставьте предлоги (with, at, in, on).
1 The process of studying deals ......... mastering new construction methods. 2 Such specialists are ......... great demand now. 3 We have quite a number ......... well-equipped laboratories ......... our disposal. 4 We write graduation theses .........the scientific problems of our research work. 5 We are provided ......... everything necessary for a scientific career.
3. Составьте предложения, используя следующие слова и выражения.
1) their speciality, get work, all the graduates, according to; 2) a wide range of, we, job opportunities, have; 3) our Institute, work, at the department of, highly-qualified teachers, many; 4) is, in our town, it, higher educational establishments, one of the largest; 5) their studies, students, their research work, the fourth-year, with, combine.
4. Найдите в тексте эквиваленты следующих русских выражений:
1) процесс обучения; 2) технология производства; 3) второкурсник; 4) дипломная работа; 5) информатика; 6) ВУЗ; 7) новейшие научные достижения; 8) высококвалифицированные преподаватели; 9) в нашем распоряжении; 10) строительная площадка; 11) ученая степень.
5.Заполните пропуски словами, данными ниже: 1 We write ...... and graduation theses on the scientific problems of our ......... work. 2 In summer the students of out faculty, besides ......... , have their practical hours. 3 We have quite a number of......... laboratories at our disposal. 4 The whole process of studying ......... with mastering new ......... methods. 5 The final and most important period in students' life is ...... of graduation work. 6 During the years of ......... the faculty has trained many highly qualified engineers.
-if he is a second-year student; -if there are the day-time, evening-time and extra-mural departments; -if the fourth-year students combine their studies with their research work; -if during practice the students master the job of a civil engineer; -if those who combine studies with their work are trained at the evening-time department.
7. Прочитайте диалог, дополнив недостающие реплики, и инсценируйте его.
An Excursion to a construction site
A group of students is asking a civil engineer questions Student: What is under construction here ?
S.: By the way, how long does it take the builders to complete it ?
C. E.: ......... S.: What materials do you use here ? C. E.: .........
S.: We see a tower-crane here. What other building machinery and lifting equipment has this team of builders ?
S.: And what about construction methods ? Which of them are used here ?
S.: Thank you for your answers. Good-bye.
8. Представьте, что вы являетесь участником международной выставки, организованной в вашем Университете. Инсценируйте данный диалог. At an Industrial Exhibition Boris Antonov is an engineer from a Tyumen Plant of Building Structures, which is taking part in an industrial exhibition at the Tyumen State University of Architecture and Civil Engineering.
Mr. Blake, a businessman from Canada, is talking to Antonov, who is working at the exhibition as a guide.
Blake: Have you seen our new model, Boris?
Antonov: Yes, and I must say it is a very up-to-date design.
B: I'm happy to hear that!
A: We are interested in buying some of these machines for our factories.
B: Are you ? How many would you like to buy?
A: I can't give you a definite answer now, I think it may be a big order. Would you like to visit the factory and talk to the Director General?
B: I'd love to if you could arrange it soon, because I am leaving Orenburg next Saturday.
A: No problem, Mr. Blake.
B: Good. Thank you ever so much.
9. Разыграйте следующие ситуации: -You have met your former classmate, who is a student of the Medical Academy now. Exchange your opinions on the process of studying.
-Your acquaintance is going to enter our University this year. Prove him/her to apply for your faculty.
-A group of American students is visiting our University . They are interested in each faculty. Tell them about the Civil Engineering Faculty.
a second-year student; to be founded; to train engineers; departments; new construction methods; to be taught; to master foreign language; graduation thesis; according to the academic plan; job opportunities
X. ADDITIONAL MATERIAL
1.Прочитайте текст и ответьте на вопросы. TEXT 1. WOOD
Wood has been a highly used building material since prehistoric times. Among other highly used construction materials there are concrete, steel, brick, stone, and plastics. They all differ in their properties and in the methods of usage. Construction materials are known to differ in strength, hardness, fire- and corrosion-resistance durability, and, naturally, cost.
Being the oldest building material, wood is also known to be the only naturally growing organic material. Is wood strong? Hardly so, because wood always contains some water which decreases its strength. But after thewood is cut, the water content starts to evaporate and as the water content decreases the strength of the cut wood and its hardness start to increase. It is a well-known fact that the drier is the cut wood the greater is its strength and hardness.
Trees are known to grow naturally, which makes wood a constantly renewable natural resource. Among other advantages of wood there are its low cost, low weight, and high workability. But, as any other construction material, wood has its disadvantages. The main ones are the following — it is not fire-resistant, it easily burns. Besides, it easily decays.
What building materials are used in construction and what are their main properties?
What decreases the strength of wood and what is necessary to do to increase the strength of wood?
What are advantages and disadvantages of wood?
TEXT 2. 1. Прочитайте текст и ответьте на вопросы. TEXT 2. WOOD PRODUCTS
Wood used for construction purposes is usually changed into laminated wood or wood panel products. Large structural wooden members are produced by glueing small strips of wood together.
Wood in panel form is more advantageous for many building purposes than boards. Why is it so? First of all, because wood panels are much easier to install than boards. They require much less labour for the process of installation. Besides, swelling (набухание) and splitting (расщепление) in panels are greatly decreased compared with boards. As to plywood panels, they are made up of thin wooden veneers glued together. It is of great importance to note that when wooden structures are designed the future stresses of their structural members must be predetermined.
Does wood as a structural material have only advantages? If not, what are its disadvantages?
Is wood a strong building material? If not, why?
3. Does the water content in the cut wood increase or decrease?
What forms is wood changed into? And for what purposes? Compare wood in panel forms with boards. What do they differ in?
What elements are plywood panels made up of?
2. Запомните и выучите следующие слова (работа в парах).
3. Вставьте соответствующие глаголы и переведите все слова (работа в парах). Model: predetermination — to predetermine — заранее определять
(a) requirement —to —
installation — to —
lamination - to -
determination - to -
evaporation - to -
(b) glue — клей — to glue — клеить
change — - to —
form — — to —
strip — - to -
decrease — — to —
veneer — — to —
board — — to —
Kinds of Wood
д. мягких пород
д. твердых пород
4.a) Прочитайте словосочетания и переведите их а русский язык.
glued board ------
laminated glass —
veneering plywood —
wood veneers ----
strip of land------
strips of wood glued together ------
б) Дайте английские эквиваленты русским словам.
1. Small (полосы) of wood are (склеены)
2. Wood in panel form is more (предпочтителен) for
some construction (цели) than (доски) .
3. (фанерные) panels are made up of (тонкие)
TEXT 3. 1. Прочитайте текст и ответьте на вопросы.
FROM THE HISTORY OF METALS
Metals began to be widely used as construction materials not so long iigo. Before the beginning of the nineteenth century metals played little structural role in the process of building. Mostly they served for joining parts of buildings. The ancient Greeks and Romans are known to use bronze for joining slabs of stone.
It was only in the eighteenth century when the first all-metal structure was built in Europe. It was a cast-iron bridge across the river Severn in England. The strength of the bridge turned out to be so great that now, more than two centuries after its construction, it still carries heavy modern traffic across the Severn.
In the first half of the nineteenth century cast iron and wrought iron were introduced and used for industrial construction in Europe and North America. Steel was not widely used, being considered a rare and expensive building material. Inexpensive steel first began to be produced and used only with the invention of the Bessemer process, in the 1850s. From that period on, metal started to be used as rather popular and useful building material. The famous Eiffel Tower of Paris was constructed of wrought iron in 1889. By that period several steel frame skyscrapers had already been built in the United States. That was the beginning of the new era; a new highly useful and popular construction material had been born and introduced into building industry.
For what purposes were metals mostly used before the beginning of the nineteenth century?
What did ancient Greeks and Romans use bronze for?
When and where was the first all-metal structure built? What can you say about its present-day condition?
What kinds of iron were introduced in the first half of the nineteenth century?
Why was steel as a building material unpopular for a long period?
What is the essence of the Bessemer process?
What was the global result of its invention?
What material is the famous Eiffel Tower constructed of?
In what country were the first skyscrapers built?
10. Are they good to live in? Would you like to live in a skyscraper?
2. Переведите отрывок письменно, пользуясь словарём при необходимости.
The Empire State Building was built in 1931 in the United States of America. Its construction took about two years. The exterior of the skyscraper is supported by a framework produced of steel. It should be noted that 60,000 tons of steel were used for its production. The Empire State Building is considered to be one of the tallest and spacious construction of the world. It can be attended by 80,000 people simultaneously.
TEXT 4. 1. Прочитайте текст и ответьте на вопросы.
What is steel as a construction material? Steel may be classified as iron with the controlled amount of carbon. The amount of carbon in steel is generally less than 1.7 per cent. Ordinary structural steel should contain less than three tenth of one per cent carbon. This kind of steel also contains small amounts of phosphorus, sulfur, oxygen, nitrogen and silicon. Like iron and its alloys, steel belongs to ferrous metals. It is a hard substance. Accordingly, it can be pulled, forged, and melted. Generally, steel, this strong metal, like other metals, is a good conductor of electricity. Alloyed steel and stainless steel are corrosion-resistant kinds of steel. Corrosion-resistant materials are known lo be widely used for plant equipment, furnaces, valves, etc.
It should be noted that steel frames as a whole and their separate parts should be carefully designed: their function is to be able to carry the loads imposed on them and supported by them.
What group of metals does steel belong to?
What substances can steel contain?
What amount of carbon does steel generally contain?
What materials can be used for producing plant equipment?
What is the construction purpose of steel frames? For what reason must they be carefully designed?
Прочитайте текст и ответьте на вопросы.
FERROUS AND NON-FERROUS METALS
All metals, with the exception of mercury (ртуть), are hard- and fire-resistant. The common properties of metals being hardness and high fire-resistance, they are widely used in modern construction.
Metals are divided into two main groups: ferrous and non-ferrous. Iron, steel and their various alloys belong to the group of ferrous metals, while the main component of non-ferrous metals is not iron.
All metals have some common properties: they can be pulled, forged, and melted. They are also good conductors of electricity.
Ferrous metals are commonly used for construction of supporting members. Steel and other ferrous metals serve as reinforcement in ferroconcrete constructions.
As to non-ferrous metals, their advantage is their being light. They are also good conductors of electricity, copper being the best one. Metals possess high resistance.
What are the properties of metals?
What metals are called ferrous and what metals are non-ferrous?
What are the properties of ferrous metals?
Where are they used in construction?
What are the properties of non-ferrous metals?
TEXT 6. 1.Прочитайте текст и ответьте на вопросы. ALUMINUM. ALUMINA
Aluminum is a considerably new structural material. For a long period it was considered to be rather expensive since its production required the use of electric power. Because of its relatively high cost, aluminum was not very popular as a construction material till the middle of the twentieth century. But now the situation is absolutely different.
Aluminum and aluminum-based alloys are extremely popular and are widely used in various forms for construction purposes.
The advantages of aluminum, compared with other popular metals, are its high strength combined with lightness. High-purity aluminum (about 99% pure) is soft and ductile but its great disadvantage is that it is not strong enough. At the same time it has high corrosion resistance and is used in construction of buildings as bright foil for heat insulation, roofing, exterior and interior architectural ornamentation.
And what about aluminum alloys? They are much more advantageous than pure substance, Aluminum alloys are much harder and stronger than pure aluminum. Besides, pure aluminum is rather difficult to cast while many of its alloys are extremely easily cast. Pure aluminum is easily alloyed with other metals. And these combinations possess a great variety of usage. For example, when alloyed with copper, aluminum possesses additional strength. Unfortunately, it is much less corrosion resistive than alloys with manganese, chromium, or magnesium and silicon.
One more advantage of aluminum is that it can be easily remelted over and over again.
Aluminum combined with oxygen forms a new oxide. Its name is alumina. Alumina is a colourless crystallic substance. It is glass hard, solid and extremely durable.
It should be also noted that being an excellent conductor aluminum is widely used in power engineering. It serves for long-distance transfer of electric power.
Why was aluminum unpopular for a long period?
What good qualities does aluminum possess?
Where is aluminum in the form of bright foil used?
What are the advantages of aluminum alloys?
Can aluminum be remelted?
In what way is alumina produced?
What are its properties?
What does aluminum serve in power engineering for?
Какие качества из перечисленных ниже могу классифицироваться как преимущества и недостатки материалов используемых для строительных целей?
ductability, poor conductance, low durability, high corrosion resistance, high purity, low strength, high cost, low cost, excellent conductance, hardness, workability, poor purity, high strength
Прочитайте текст и выполните задание.
Air, water, sand, salt, coal, petroleum are familiar elements in the everyday life, but these form the basic sources of the world's fastest growing (расти) industry -plastics.
From a purely engineering viewpoint the following characteristics of plastics explain their increasing acceptance by industries and consumers alike. These characteristics are usually shared by all plastics, but there are variations between individual materials: lightweight (sometimes high strength to weight ratio); corrosion resistance; electrical and thermal insulation; ease of fabrication; transparency in some materials; ease of the increasingly successful application of plastics which take advantage of these characteristics have meant that plastics materials are now manufacturing materials in their own rights and not substitutes. The high strength to weight ratio of some plastics offers big field in the coming age of space travels and rockets.
The same benefits of light weight with good strength and absence of corrosion offer tremendous potential as alternatives to traditional building materials. New shapes in building are absorbing the attention of the architects. Plastics offer many of properties for these designs and their application in exotic structures is an example.
2.The characteristics of plastics, which increase its use in industry and by consumers, are …
3. It will be used in this age of space travels and rockets because of …
4.Plastics offer new shapes in building and application in exotic structures because of combination of …
Прочитайте текст и выполните задание после текста.
FROM THE HISTORY OF CONCRETE Mass or plain concrete dates from very early days. It was employed in ancient times by the Egyptians, Romans and Greeks in the construction of aqueducts and bridges, in the construction of roads and town walls. Romans used it even in under-water structures some of which have survived till our time. They also employed concrete as a filling between the brick and stone ribs of the vaults and arches. A large part of the Great Chinese Wall (the 3rd century before our era) was also built of concrete.
The concrete remains of the foundations of buildings built several thousands years ago have been found in Mexico. As cement was not known in those times, concrete was made of clay and later of gypsum and lime. The knowledge of the concrete use seems to have been lost during the Middle Ages, and it was not until the eighteenth century that its value was rediscovered. Nowadays concrete is made in up-to-date machinery with very careful regulation of the proportion of the mix.
The idea of strengthening concrete by a network of small iron rods was developed in the 19th century, and ferro-concrete was introduced into engineering practice. Since that time the development of reinforced concrete work has made great progress. And the reasons of this progress were evident. Between 1880-1890 several reinforced concrete buildings were erected in the United States, and since 1896 the increase in the amount of construction with this material has been remarkable.
2. Закончите предложения в соответствии с содержанием текста. Полученные предложения переведите на русский язык.
1. Mass or plain concrete was employed in ancient times in …
2. Romans also used concrete as a filling…
3. As cement was not known in ancient times concrete was made of …
4. The knowledge of the concrete use … in the Middle Ages.
5. Nowadays concrete is made …
6. The idea of strengthening concrete by … was developed in the 19th century.
7. Between 1880-1890 … were built in the United States.
3. Прочитайте снова дополнительные тексты и составьте резюме, используя следующие выражения: The text is about …
At the beginning of the text the author stresses (underlines, points out) that …
Then the author describes smth (suggests, states that) …
After that the author passes on to (description of, statement of, analysis of …}
At the end of the text the author comes to the conclusion (pays attention to the fact) that…
Прочитайте тексты и переведите их.
Напишите резюме, используя выражении после тестов. Text 1. Building Construction
The construction of the homes and buildings in which people live and work has been a major industry ever since early human beings first made huts of sticks, mud, or rocks. Methods of building construction have been constantly improved since those first crude structures. Modern skyscrapers can be built within a year or two. Prefabricated buildings, with their various parts made in factories by assembly-line methods, can be built in a day or two, but are rarely as durable as traditionally made buildings. A building has two main parts, the substructure (the part below ground) and the superstructure (the part above ground). The substructure is usually called the foundation. It includes the basement walls, even though these may extend above the ground. Both the substructure and the superstructure help to support the load (weight) of the building. The dead load of a building is the total weight of all its parts. The live load is the weight of the furniture, equipment, stored material, and occupants of a building. In some regions, the wind load of a building is important if the structure is to withstand storms. The snow load may also be an important factor. In some areas, buildings have to be constructed to withstand earthquake shocks. Foundations are the chief means of supporting a building. They carry both the dead and live loads. There are three main types of foundations: (1) spread, (2) pier, and (3) pile. Spread foundations are long slabs of reinforced concrete that extend beyond the outer edges of the building. Such foundations are not so firm as those based on solid rock. The footing areas in contact with the soil must be of sufficient size to spread the load safely over the soil and to avoid excessive or uneven settlement. Any such settlement would cause walls to crack or doors to bind. Pier foundations are heavy columns of concrete that go down through the loose topsoil to a bed of firm rock. This bed may also be sand, gravel, or firm clay. If the bed consists of firm clay, the pier is usually enlarged at the base, to increase the bearing area. Pile foundations are long, slender columns of steel, concrete, or wood. Machines, called pile drivers hammer them down as deep as 60 metres to a layer of solid soil or rock. Workers can tell when the columns reach their proper depth by the number of blows the pile driver needs to drive the columns a few centimetres deeper. These columns transmit the building load to the supporting soil. Most skyscrapers are supported by rock foundations
Text 2. Types of construction
In load-bearing-wall construction the walls transmit the load to the foundation. In skeleton construction, all loads are transmitted to the foundation by a rigidly constructed framework made up of beans, girders and columns. This skeleton carries the roof, walls, and floors, together with their loads. Load-bearing-wall construction is usually most economical for buildings less than four storeys high, but skeleton construction is better for taller buildings. All buildings in the skyscraper class are of skeleton construction. The first building to have skeleton construction was the 10- storey Home Insurance Building in Chicago. Completed in 1885, this building was the world's first skyscraper. Many parts of a building have no structural function. Partition walls and curtain walls carry only their own weight and serve to divide the interior of a building or to keep out the elements. Other nonload-bearing parts include windows, doors, stairs, and lifts. In one method of construction, called tilt-up construction, concrete wall panels are formed at ground level. Cranes or derricks then lift them into position. Lift-slab construction may be used for positioning roof and floor slabs. These slabs are formed with concrete at ground level, within the framework of the building. They are then lifted into place using hydraulic jacks. Beams, girders, and columns support a building much like bones support the body. They form the skeleton of the superstructure, and bear the weight of the walls and each floor of the building. Beams and girders run horizontally. Girders are usually larger than beams. Closely spaced beams are called joists, especially in wooden buildings. Purlins are small beams that brace rafters or girders and help provide the structure to support roofs. Beams above window and door openings are called lintels. Slabs are beams whose width is greater than their depth. Columns are heavy vertical supports that carry the load of beams and girders. Trusses consist of many wood or steel supports that are connected in triangular patterns. They provide the strength and rigidity to span large distances with relatively small amounts of material. Arches are curved supports that usually extend over openings.
Text 3. Prefabricated Construction
Prefabrication has become an important part of most types of building construction. Prefabricated sections of a building are produced in large quantities in a factory and then shipped to various construction sites. This procedure may allow work to continue despite poor weather conditions and should reduce any waste in time and material at the site. As a result, costs are lowered and construction time decreases. Many types of building sections can be prefabricated. For example, entire walls may be prefabricated for a wooden-frame house. Huge wooden arches are prefabricated for use as supports in churches, gymnasiums, and other buildings.
Concrete beams, floors, roofs, and wall panels may be precast for many types of structures. Entire buildings may be constructed in a factory and then transported to the desired location. Prefabricated structures are sometimes made by a process called modular construction, first used in Japan. Modular construction refers to the use of a standard measurement as the basis for all building materials. The size of the module may vary considerably from country to country. In the United States, the basic module is 10 centimetres. All building parts are designed so that each dimension equals this measurement. Modular parts are also used in buildings that are not prefabricated.
Text 4. Building Stone
Building stone ranks in importance with steel as a construction material. Stone is used for the foundations, walls, and steps of buildings, for the support of piers and bridges, and for finishing and decorating all types of structures. Crushed stone accounts for most building stone used in construction. Crushed stone is quarried stone crushed into small pieces suitable for such uses as the surfacing of roads and industrial construction. Dimension stone is stone in natural blocks or slabs cut in definite shapes and sizes. Builders expect good dimension stone to last at least a hundred years. The best dimension stone has the fewest pores or air cells, making it able to resist the wearing effects of weather. Stone with large, open pores will chip off if water freezes and expands in the pores. Dimension stone includes granite, limestone, sandstone, marble and slate. Granite is one of the strongest of all the building stones. However, it is difficult to cut and handle because it is extremely hard. It is used extensively in the construction of public buildings. Granite can be polished to a glossy finish, and is an excellent background for carvings and lettering. Limestone is a hard and lasting building stone that can be cut easily and shaped with saws, planes, and even lathes. These buff or gray stones are sometimes placed over the rough stonework of a building to make an attractive surface. Limestone is also used to tile floors, and for sills, steps and trimming. Marble is the most elegant building stone. Pure marble is white, streaked with veins of black, gray, green, pink, red, and yellow. Builders use marble to make monuments and tombstones, and to decorate stairways, hearths, floors, and panelling. Slate is fine-grained rock that can be split easily into thin slabs and used for roofing shingles and flagstone flooring.
Text 5. Constructing a skyscraper
New methods in the design and construction of skyscrapers have been closely related to the development of computers. Engineers use computers to solve the complex mathematical problems involved in such construction projects. Computers do this work quickly by breaking the design down into a limited number of precalculated elements. Before construction begins, engineers determine the strength of the soils that will lie underneath the new building. With this information, they can design the proper foundation. After the building site is cleared, levelled and drained of water, excavation (digging) begins. Mobile diggers usually excavate the foundation. Ground made of rock may be excavated by blasting. After the excavation is finished, the footings (base) and the superstructure are built. Most steel used in the superstructure, such as beams, girders, and columns, comes prefabricated. Each piece of steel should have a number indicating the exact place where it should be used. When the steel is raised into place, workers fasten the pieces together temporarily with bolts. Later, welders and riveters join these pieces together permanently. Many kinds of cranes and derricks are used in the construction of skyscrapers. The two main kinds are mobile cranes and tower cranes. Mobile cranes are mounted on trucks or special vehicles and can manoeuvre around the outside of the building to hoist materials and equipment from various locations. Tower cranes are supported on a steel tower erected next to or inside a building's framework. After workers complete the superstructure and outside walls, the building is ready to be finished, decorated and furnished.