Ductility. Steel can undergo large plastic deformation before failure, thus providing a large reserve strength. This property is referred to as ductility. Properly designed steel structures can have high ductility, which is an important characteristic for resisting shock loading such as blasts (взрыв) or earthquakes. A ductile structure has energy-absorbing capacity and it will not be suddenly collapsed. It usually shows large visible deflections (прогиб, отклонение) before failure or collapse.

Properties of steel can be predicted with a high degree of certainty. Steel in fact shows elastic behavior up to a relatively high and usually well-defined stress level. Steel properties do not change considerably with time.

Advantages of steel.

Steel structures can be erected quite rapidly.

Steelstructuresingeneralcanberepairedquicklyandeasily.

Steel is highly suitable for prefabrication and mass production.

Steel can be reused after a structure is disassembled.

Steel buildings can be easily expanded by adding new bays or wings. Steel bridges may be widened.

Steel structures have relatively good fatigue(усталость) strength.

Disadvantages of steel in certain cases.

Steel structures may be more costly than other types of structures.

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The strength of steel is reduced when heated at temperatures commonly observed in building fires. Also, steel conducts and transmits heat from a burning part of the building quite fast. Consequently, steel frames in buildings must have adequate fireproofing.

Steel structures are subjected to air, water and corrosion and shouldbepaintedregularly. Applicationof weathering and corrosion-resistantsteelmayeliminatethisproblem.

Steel members are in general more subjected to deformation than reinforced concrete compression members.

TIMBER

The building industry is increasingly recognising the potential results available from working with environmentally focused products i.e. timber, that combine clean aesthetics and structural properties.

Advantages of timber.

Timber is an excellent insulator: brick-built houses are also known to have outstanding insulating properties, but timber surpasses them.

Timber is an elastic material: in comparison with brick or concrete walls, timber walls don’t have to be very thick. A20 cmwall, for example, is strongenough to protect against the winter cold, if it has a proper treatment.

Timber houses are very attractive; they don’t need special decorative finishes.

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Disadvantages of timber.

Timber is vulnerable (уязвимый) to vital forces like termites (термиты), woodworms (личинки древоточца) or wood ants (муравьи).

Natural forces like the sun, fire, water and etc. can have unfavorable effect on timber.

Timber is subjected to shrinking (усадка) and swelling (набухание, вспучивание). Timber has a natural ability to absorb water which is also known as hygroscopy.

CONCRETE

Concrete is an artificial stone-like material used for various structural purposes. It is made by mixing a binding material as cement and various aggregates i.e. inert materials, such as sand, crushed stone, pebbles (галька, мелкий булыжник), gravel, shale, etc with water and allowing the mixture to harden by hydration (гидратация – присоединение воды к ...).

Advantages of concrete.

Concrete is economical when ingredients are readily available.

Long life of concrete and relatively low maintenance requirements increase its economic benefits.

It is not subjected to corrosion or decay as other building materials.

Concrete has the ability to be moulded or cast into almost any desired shape.

Concrete is non-combustible material which makes it fire-safe and able to withstand high temperatures.

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It is resistant to wind, water, and insects. Therefore, concrete is often used for storm shelters.

Disadvantages of concrete.

Concrete has a relatively low tensile strength compared to other building materials.

Low ductility.

Low strength-to-weight ratio.

Concrete is subjected to cracking (трещинообразованию).

FOR SELF EXAMINATION

TEST (part II)

1.The properties of building materials

a)aren’t very important when designing a structure

b)should be always taken into consideration

2Cement, brick and concrete are the examples of

a)artificial building materials

b)natural building materials

3.High cost and low fire-resistance are

a)advantages of main building materials

b)disadvantages of main building materials

4.The only renewable natural building material is

a)wood

b)clay

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5.Durability, strengthandheat-insulationaretheproperties of

a)stone

b)timber

6.The drier is the cut wood

a)the greater is its strength

b)the less is its strength

7.Hardwoods are usually used for

a)bearing structures

b)decoration and veneering

8.In cut trees water content is

a)constantly increasing

b)constantly decreasing

9.Aluminium is

a)a poor conductor of electricity

b)a great conductor of electricity

10.Russia is

a)extremely rich in timber, clay, metals and rock

b)very poor in these resources

11.The components for producing bricks are

a)sand and water

b)clay and mortar

12.The building material used for foundations is

a)stone

b)laminate

13.Plastics are

a.modern building material

b.ancient building material

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14.In modern construction the variants of plastics are

a)extremely wide

b)very limited

15.Cement and lime are referred to

a)binding building material

b)secondary building material

16.The most popular type of cement nowadays is

a)Pozzolanic cement

b)Portland cement

17.When concrete is compressed it becomes

a)weaker

b)stronger

18.The kind of concrete chiefly used in severe climate is

a)high-early-strength concrete

b)foam concrete

19.The famous Eiffel Tower in Paris was constructed of

a)wrought iron

b)cast iron

20.Corrosion is the prime enemy of

a)metals

b)bricks

21.The best material for reinforcing concrete is

a)steel

b)iron

22.Aluminium wasn’t popular in construction till the middle of the 20-th century because of

a)its lightness

b)its high cost

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23.A kiln is used when producing

a)glass

b)plastics

24.The building material derived from petrochemicals is

a)cement

b)plastics

25.Marble, granite, limestone are the examples of

a)dimension stone

b)crushed stone

26.Themostattractive andthehighestqualitybrickiscalled

a)refractory bricks

b)face bricks

27.The auxiliary building material made of sand, water and cementing mixtures, applied for interior and exterior finishes is

a)clay

b)stucco

28.In ancient times bricks were made by

a)burning in a kiln

b)drying in the sun

29.Iron and steel belong to

a)ferrous metals

b)non-ferrous metals

30.The building material never used for fireproof structures is

a)artificial stone

b)timber

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PART III

PARTS AND ELEMENTS OF A BUILDING

Words to be remembered: girder – ферма, главная балка

truss – ферма, стержневая несущая конструкция slab – плита

beam – балка

pillar – столб, колонна

span – пролет, расстояние между опорами foundation – фундамент

basement – цоколь, подвальное помещение floor – межэтажное перекрытие, этаж exterior wall – внешняя стена

roof – крыша

partition – перегородка, ненесущая внутренняя стена ceiling – потолок

support – опора, несущая конструкция column – колонна

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shape – форма, вид formwork – опалубка

substructure – подземная часть сооружения superstructure – надземная часть сооружения, надстройка premises – помещение

flexibility – гибкость, упругость, эластичность plasticity – пластичность

cladding – облицовка, наружная обшивка joist – прогон

arrangement – размещение, расстановка crack – трещина, раскол

damage – повреждение, разрушение failure – разрушение

skyscraper – небоскреб

bar – стержень, арматурный пруток

dead load – постоянная нагрузка (собственный вес) live load – временная нагрузка

gravity load – нагрузка от собственного веса settlement of foundation – оседание фундамента

heaving – вспучивание, выталкивание пласта породы или конструкции из грунта

freezing – промерзание thawing – оттаивание pitch – скат, уклон

to bend – изгибать, гнуть

to transmit – передавать (нагрузку)

to increase – увеличивать(ся), повышать to reduce – уменьшать, понижать

to separate – разделять

to cover – накрывать, покрывать

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Task. Read and translate the text, do the exercises given below.

TEXT 1. TYPES OF STRUCTURES

In structural engineering structures are classified by the way they resist loads:

masonry structures* – load bearingwalls resistloads transmitted to themby floor slabs;

framed structures* – a steel or concrete skeleton collects loads from plate elements and delivers them to the foundation;

shell structures*– a curved surface* covers space and сarries loads;

tension structures* – cables are stretched between anchor structures* membranes;

pneumatic structures* – a membrane tightened to the ground is supported by internal air pressure.

by the material used: concrete and reinforced concrete structures, steel structures, masonry structures, wooden/timber structures.

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