State which of the given sentences denote the description of the cement and which of them denote concrete.

1. This material is most widely used for the purpose of binding together masonry units such as stone and brick. 2. This materials is also known to be the most important component of concrete. 3. This kind of material may be considered an artificial conglomerate of crushed stone, gravel or similar inert material with a mortar. 4. The material which contains alumina has an extremely high rate of strength increase. 5. The fundamental object in proportioning this material is the production of a durable material of requisite strength, water tightness and other essential properties. 6. The most accurate method of measuring proportions is to weigh the required quantities of each material.

 

Choose the correct answers.

1. What influences the choice of building materials?

a) The choice of building materials is governed by the type and the function of a building. b) Availability, cost and physical properties are the main considerations for an engineer in selecting materials for construction. c) The techniques and methods of construction are the main factors influencing the choice of building materials.

2. What are lime, gypsum and cement most widely used for?

a) These three materials are not widely used for the purpose of binding together masonry units. b) They are used as components to produce concrete. c) With the large-scale construction, lime, gypsum and cement may be considered to be the most important binding materials.

 

Text 7

THE PROBLEM OF DURABILITY IN BUILDING

Durability is a very elusive property. If the problem is regarded critically the question may be asked: What is the degree of durability required?

The durability of any material or method of construction (if we regard walls) depends upon the conditions of exposure. External weathering with rapid alteration of temperature and moisture content results in deterioration of structure and materials which would be unaffected over very long periods if used inside. It is quite unnecessary to apply the same standards to materials to be used under cover as to those for external use. The severity of the conditions of exposure depends not only on site and aspect but also on the design of a building as a whole. The shelter afforded by projecting eaves, cornices, throatings and hood moulds-very much simplifies the problem of rain exclusion and deterioration of surface finished generally. So it is necessary to take into account the increased severity of exposure to the weather.

In selection materials the practice of experience is not enough.

Experience of previous behavior is the most unreliable guide when a material is used in a novel manner. Many disastrous failures have resulted from the supposition that. An unfamiliar combination of familiar can be used with complete freedom. The technique of scientific testing of materials is more reliable. It has accumulated definite principles on which of appraisal of durability may be made.

The durability of a walling material in service depends upon its chemical composition, pore structure and to a great extent upon its mechanical strength. Materials vary in the extent to which their pores will be filled with water.

In some materials nearly the whole of the pore space may be filled, in others the water may only occupy 70 or 80 per cent of the pore space.

In certain cases the effects of frost may be rendered more severe by the presence in a material of certain salts in solution. Chemical attack and pore structure are interrelated.

Thus, it is the technique of scientific testing that should be used when the problem of reliance is concerned in the sphere of building materials.

 

VOCABULARY NOTES

 

1) elusive property –ухильна властивість

2) degree of durability – ступень міцності

3) moisture content – зміст вологи

4) eaves – карнизи

5) cornice – карниз

6) to simplify – спрощувати

7) deterioration – погіршення

8) previous – попередній

9) behavior – поведінка

10) to a great extent – значною мірою

11) appraisal –оцінка

12) hood mould – частина каналізаційного люка

13) throating – жолобок

 

EXERCISES

 

1) Find the English equivalents to the following word combinations:

потрібна міцність; залежати від умов; швидка зміна температури; для зовнішнього застосування; проект будівлі; у цілому; братии до уваги; вибір матеріалу; наукове випробування.

 

2) Answer the following questions:

1) What does the durability of any material depend upon?

2) What does external weathering and moisture content result in?

3) What have many failures resulted from?

4) What technique is more reliable?

5) What does the durability of a walling material depend upon?

6) How may the effects of frost be rendered?

7) What technique should be used when the problem of reliance is concerned?

 

 

Text 8

 

FOOTINGS AND FOUNDATIONS

 

The more common types of foundation structure are: isolated spread footings (one to each column); combined footings (one to two columns); and mat, or raft, foundations (all columns resting upon a heavy slab).

These forms may sometimes rest directly on the bearing soil or they may rest on the heads of piling. Sometimes the columns are set on large cylinders of plain concrete, from 4or 8 ft. in diameter and extend to rock or other hard stratum at depth. This form is called “pier” or “caisson” foundation.

Spread footings may be used under either walls or columns and may be of timber, steel, plain masonry, or reinforced concrete.

The problem is to enlarge the base sufficiently to secure bearing area to carry loads.

Wall Footings – the footings in this case act as a cantilever beam with the load acting upward and the support at the middle. It is commonly assumed that the bearing is uniformly distributed over the bearing area, although the bearing may be somewhat greater at the middle that at the edges.

Continuous footings under columns – when footing are built continuously under columns, the footing takes a beam carrying concentrated loads at column points acting downwards and distributed load acting upward. The distribution of the pressure cannot be calculated directly, but the problem is to proportion the width of the footing stab so that the slab as a continuous beam under a distributed load upward will have upward reactions at column points not less than the column loadings.

Floating foundations is a term applied to practically monolithic footings built under an entire structure which have been used widely for construction on soils of more or less plastic nature. Floating foundations have been constructed as slabs or mats, a combination of beams and slabs, inverted barrel arches and slabs, and inverted groined arches.

The obvious advantage of floating foundations is that if uneven settlement occurs, serious injury to the structure does not result.

Pile foundations are used in the areas where the other kinds of foundation cannot be constructed. By driving bearing piles, the support of structure is transferred in an irregular manner to the earth stratum. The proportions of the load carried down by the piles and by the intervening soil depend on the nature of the soil – the stiffer the soil, the greater proportion is carried thereby.

Timber piles. - Timber piles have been used almost exclusively in the past in foundation work; but with the growing scarcity of timber, and the development of concrete, reinforced concrete piles are coming to be extensively used.

Pile driving. – Pile may be driven by means of a pile driver or a water jet. Pile drivers may be classed as drop hammers and steam hammers.

The steam pile driver has many advantages over the drop hammer. Drop hammers operate at about 5 or 6 blows per minute, while steam hammers strike about 60blows per minute for a single-acting and 120 per minute for a double-acting. After piles are driven, they are sawed off at a given elevation, and the foundation footings are placed directly thereon, the heads of the piles projecting into the concrete from 6 to 12 in.

The engineer in charge of pile driving should carefully inspect the piles previous to driving so that they meet the specifications and, after they are driven, to discover injured piles.

Some other kinds of foundation work. – Pier foundations are used where a stratum of high supporting capacity is under soil strata.

Cofferdams are enclosures constructed to exclude water from the area of operation during construction.

Caissons – the word “caisson” is derived from the French word meaning “case”.

As applied to engineering construction, a caisson may be defined as a large watertight box used to exclude water or other fluid and semi fluid materials during excavating of foundations and the construction of substructures and ultimately becoming an integral part of the structure. This box or caisson, may be “open”, without a bottom, the water being allowed to rise naturally inside; or may have a bottom and be carried down by building the masonry pier inside. If the box is inverted, the water may be excluded by air pressure, and the box becomes a pneumatic caisson consists of a box with cross walls. Sometimes the caisson is constructed of reinforced concrete or a steel cylinder.

EXERCISES

 

1. Read and translate the text.

2. Make a detailed plan of the text.

3. State the main idea of the text, and make an essay.

Text 9

WALLS

 

Wall are constructed to enclose areas and to support the weight of floors, roofs, earth or water. They are classified as follows:

a) walls to resist vertical pressures,

b) walls to resist oblique thrusts.

The first section of heading includes all house walls, solid or hollow, supporting single floors, and couple close raftered roofs. The second section includes all walls carrying the trusses of framed roofs. Inside walls serve as partitions or divisions for several rooms inside the dwelling. Inside walls may or may not support other parts of the structure.

An outside wall rests directly on the foundation wall forming a bearing unit for the upper floors and the roof and an enclosure for inner construction. Outside walls are made of wood, steel (for retaining walls), brick, stone, concrete blocks or concrete, or combination of two or three of the foregoing materials, cane and adobe.

Classification of Stone Walling. – This is classified as follows:

1) Rubble.

2) Block-in-Course.

3) Ashlars.

Rubble walls are those built of thinly-bedded stone, generally under 9 inches in depth, of irregular shapes as in common or random rubble, or squared as in coursed rubble.

Block-in-Course is composed of squared stones usually larger than coursed rubble, and under 12 inches in depth.

Ashlars is the stone 12 to 18 inches deep, dressed with a scrabbling hammer, or sawn to blocks of given dimensions and carefully worked to obtain fine joints. The length of soft stone for resisting pressure should not exceed three times its depth; the length in harder stones, four to five times its depth; the breadth, from one-and-a-half to twice its depth and breadth in harder stones, three times its depth.

Reinforced Brickwork – It is brickwork which has been strengthened by the introduction of steel or wrought iron in the form of either flat or rod bars, woven wire or expanded metal. Such brickwork is capable of resisting tensile and shear stresses, in addition to compressive stress. Reinforcement of brickwork also improves the longitudinal bond of thick walls. The brick walls are reinforced at every third course with steel meshed strips.

Cavity Walls – This type of construction is now very common and is generally preferred to solid wall construction for many types of building, especial houses.

A cavity wall is usually an external wall. It consists of two separate walls of brickwork, having a cavity between, and connected together by metal ties. This double wall is generally 11-in. thick, consisting of 4.5 in. inner and outer leaves and 2-in. cavity. Such a wall is adequate for a two-storied building of the domestic type. The chief merits of cavity walls are:

1) they prevent rain from penetrating to the internal face,

2) they have a high insulating value,

3) they are economical.

VOCABULARY NOTES

1) dwelling – житловий будинок

2) rubble walls – бутові стіни

3) brickwork – цегельна кладка

4) cavity wall – проміжна стіна

5) dimension – величина

6) to strengthen – підсилювати

7) insulating value – ізоляційна цінність

8) reinforcement – підкріплення; арматура

EXERCISES

 

1) Find the English equivalents to the following word combinations:

огороджувати; балка; зовнішні стіни; фундаментальна стіна; металеві затиски ; тривалий зв’язок; неправильна форма; перевага; запобігати дощу; арматура.

2) Answer the questions:

1) Why are walls constructed?

2) What kinds of walls do you know?

3) Where does an outside wall rest?

4) What materials are rubble walls built of?

5) What is ashlars and what is its depth?

6) What materials strengthen reinforced brickwork?

7) What does cavity wall consist of?

8) What is the merit of cavity wall?

 

3) Translate into English:

1) Стіни використовуються для огородження територій та підтримки ваги поверхів, шиферу, землі чи води.

2) Зовнішні стіни розташовані на фундаментальній стіні, формуючи несущий елемент для верхніх поверхів та шиферу та огородження для всієї внутрішньої конструкції.

3) Бутові стіни зроблені з тонкого-каміня, що знаходиться на глибині 9 дюймів.

4) Блочні стіни вироблені з квадратних каменів, що звичайно більше ніж бутові та знаходяться на глибині 12 дюймів.

5) Проміжна стіна підходить для двохповерхової будівлі домашнього типу.

6) Проміжна стіна складається з двох окремих стін, між якими є прохід та які пов’язені металевими затисками 

Text 10

WALL UNITS

 

Wall-slabs – Wall-slabs are mostly used for the construction of partitions or walls which carry no load but serve only the purpose of enclosing space. In some cases, precast wall units are also used to form load-carrying walls. In the construction of external walls for houses and multi-storied flats the tendency has been towards a steady increase in the size and weights of the precast units. Whole walls with windows and door incorporated are precast as single units. It appears that the optimum size and shape of precast units for wall construction is a slab of such size as can be safely transported from a permanent factory to the building sites. It is advantage if the shape of the units is similar all walls and floors. This slab structure possesses properties which are generally desirable in house construction: flat walls and ceilings without the usual breaks in the surfaces due to beams and columns; low weight, and good heat and sound insulation; small quantities of mortar, and simple erection; short time and low costs of construction.

Sections Assembled from Block. – like floor-slabs, wall sections are frequently assembled from precast hollow blocks of light-weight concrete.

Interlocking Blocks – a type of walling quickly and easily erected makes use of wall-blocks consisting of slabs with enlargements at both ends over half the weight of the unit. These enlargements have centre holes. The weight of each block is designed so that two men can carry it quite easily.

To erect the wall, strip foundations or foundation blocks are prepared in-situ, with reinforcing rods projecting vertically at centers equal to the spacing of the holes. The blocks are set in mortal so that the holes register and form hollow cylinder. As soon as the first live rows are laid, reinforcing bar is placed in each hole overlapping the vertical bar of the foundation and leaving lap for the next lift. All holes are now grouted in carefully, and the next lift is erected by repeating the same process. In lintels over doors and windows the nominal reinforcement of the block has to be replaced by a working reinforcement in accordance with the load to be carried. Precast eaves may be shaped to the architect’s requirements. They have similar 5-in. holes to provide a solid anchorage into the wall piers.

With labour reasonably well organized, such a house of 22 ft. by 15 ft. high, may easily be erected in two days after the foundations are ready, counting one day the erection of walls and another day for the precast roof.

Tilt-up Construction – Tilt-up walls are cast on the ground in one or more sections, then lifted upright and attached to each other. Sometimes these panels are made with glass or other insulating material inside. In the structure, the panels may be connected to the floor, to partitions, to columns, and to each other by welding steel details together, by bolting, by mortaring, or by any other suitable and possible means. Precast wall panels can also be used in a large multistory structure. When made with an insulating material in the middle, they are often called “sandwich” walls.

Sandwich Construction – one of the principal properties required for external wall is a satisfactory value of thermal insulation. Prefabrication offers good possibilities of improving the thermal insulation properties of concrete walls by the inclusion of layers of high-grade insulating materials. The precast units are made of storey-height and of the full length of each house. Prefabricated near the site, they consist of an inner and outer facing of reinforced concrete and a core of cellular-glass insulating blocks. These walls have an over-all coefficient of heat transmission of 0.20. Inner and outer facings tied together with expanded metal shear-ties, and edges of the panels are tongued and grooved, for water-tightness. Inserts for anchoring panels to structural steel framing are welded to the inside wire mesh, which holds them in proper position during the casting operation.

Retaining Walls – A retaining wall, usually built of stone, plain concrete, or reinforced concrete, is a wall built to sustain the lateral pressure of the earth or other material possessing more or less frictional stability. Such walls depend for their stability either on their own weight or on their own weight and additional weight of the laterally supported material. Retaining walls are most commonly used for lateral supports of earth.

EXERCISES

 

1) Read and translate the text.

2) Make a detailed plan of the text.

3) State the main idea of the text and make the annotation.

Text 11

PARTITIONS

 

Partitions are walls which are used to divide building into rooms, corridors and cubicles. They also often act as deep trusses to support the joists of floors, purling and ceiling joists of roofs, etc. Partitions may be classified under following: timber, clay and terra-cotta, concrete, sawdust concrete, plaster, wood-wool cement, asbestos-cement, and metal.

Timber Partitions. – they consist of vertical members called studs, which are secured to two horizontal lengths of timber, the upper being the head and the lower, the sill. One or booth may be either lathed and plastered or covered with boarding, plywood sheets, wall boards, etc.

This class of partition is in common use. Because of its lightness, it is usefully employed when there is no supporting wall below. A disadvantage is its deficient fire-resisting quality.

Clay and Terra-Cotta Brick and Block Partitions – the commonest type of clay partition is the ordinary solid brick.

Wall of 4 ½ in. or more in thickness. Such walls are relatively strong and fire-resisting, but their weight precludes their use for partitions on upper floors unless provision in the form of girders or lower wall is made for their support. Holly clay units, either bricks or blocks, are comparatively light and yet are sufficiently strong for the construction of non-load bearing partition. In general, the blocks are built in cement mortar and are bonded in the usual way with staggered vertical joints. The following are the merits of this blocks: satisfactory mechanical strength, lightness in weight, good head and sound insulation, fireproof, non-shrinkage and vermin proof.

Precast Concrete Block Partition – both solid and hollow blocks are made. There are three of precast concrete blocks, namely:

1) Concrete blocks used for load bearing walls and made of dense aggregate such as broken stone, heavy blast furnace slag and crushed bricks.

2) Concrete blocks used for load bearing wall and made of lighter aggregates including foamed slag, clinker, expanded state and pumice.

3) Concrete blocks used for load bearing partitions and made of aggregates similar to those for type 2.

Sawdust Concrete Blocks Partitions – Sawdust concrete (so called because it is a mixture of cement and sawdust) is used in the production of building and partition blocks. They are composed of cement, fine aggregate and chemically treated sawdust. They are light in weight and have satisfactory heat insulation and fire-resisting values.

Plaster Slab Partitions – these are made of calcium sulphate. This is mixed with water, and sand may be added to the mix. The slabs are made by casting the material in wood or metal moulds. They set quickly. In order to decrease their weight many thicker slabs are cellular. The slabs are bedded and jointed in lime mortar; plaster of Paris may be added.

Plaster boarded Partitions – plasterboard consists of gypsum plaster compressed between two sheets of stout paper. The boards are made in various sizes and are used chiefly for forming ceilings and covering internal partitions.

Wood-Wool Cement Partitions – this material consists of a mixture of wood-wool (wood shavings) and Portland cement: gypsum may be added. Long shavings from 1/8 to 1/4 in.

Wide boards are coated with liquid cement consolidated into slabs by means of a machine press and then stored to mature. These slabs are very light they have good heat and sound insulating qualities, are fire-resistant, can be easily fixed and sawn and provide a good key for the plaster which is applied to the surface after fixing

Asbestos-Cement Partitions – they consist of two flat sheets of asbestos-cement, each approximately 5/12 in. thick, attached to an inner corrugated sheet (1/5 in thick) of similar material. The sheets are jointed in cement mortar and painted or distempered as required. This forms a light, durable, fire-resisting and wall insulated partition.

Metal Partitions – Mild steel and bronze are two of several metals which are used in the manufacture of partitions. These may be designer to consist of a series of panels. The Panels vary from l 1/2 in. Thick.

Steel or 1/8 to 1/4 in. thick bronze. Partitions may also be constructed of bronze or nickel alloys extruded over wood panels or cores.

 

VOCABULARY NOTES

 

1) Partition – перекриття

2) Fire-resistant quality – вогнестійка якість

3) sawdust – тирса

4) precast concrete – збірний бетон  

5) plaster of Paris – гіпс

6) clay and terra-cotta brick and block partitions – глиняні, теракотоцегельні та блочні перекриття

7) Precast concrete block partitions – блочні перекриття зі збірного бетону

8) sawdust concrete blocks partitions – блочні перекриття з тирсового бетону

9) plaster boarded partitions – штукатурно – плиточні перекриття

10) mortar – розчин

11) expanded state - розширенні плити.

12) moulds - багети.

13) to mature –довести до зрілості

 

EXERCISES

 

1) Find the English equivalents to the following word combinations:

Недолік; тверда цегла; бетоні блоки; розширені плити; легкість; наповнювач; фанера; рідкий цемент; несучі стіни; досить міцний; механічна міцність.

 

2) Find the Ukrainian equivalents of the following word – combinations, given below:

1) panels                                         відбирати

2) thickness                                    складатись

3) plaster                                        штукатурка

4) boarded partitions                      дерево

5) bronze                                        опорна стіна

6) to consist of                            бронза

7) wood                                       покриття

8) supporting wall                      товщина

9) to cast                                     панелі

10) covering                                дощаті перекриття          

 

3) Answer the questions:

1) What are partitions?

2) What kinds of partitions are known to you?

3) What it the advantage and disadvantage of timber partitions?

4) What’s the сcommonest type of clay partitions?

5) What’s the sickness of solid brick walls?

6) How many types of precast concrete do you know and what are they?

7) Where’s sawdust concrete used?

8) How are the slabs made?

9) What do plaster boarded partitions consist of?

10) What metals are used in the manufacture of metal partitions?

11) What are panels and what’s their size?

 

4) Translate into English:

1) Перекриттями називаються стіни, що розподіляють будинок на кімнати, коридори та кабінеті.

2) Через свою легкість дерев’яні перекриття використовуються, коли знизу нема опорної стіни.

3) Найбільш поширений тин глиняного перекриття – це звичайна стіна з твердою цегли, що складає 4 1/2 дюйма в товщину.

4) Тирсовій бетон використовується для будування будівлі та блочних перекриттів.

5) Плити виготовляються шляхом відбору матеріалу для дерев’яних або металевих багетів.

6) Вошки можуть бути різних розмірів та використовуються для виготовлення стель та покриття внутрішніх перекриттів.

 

Text 12

 

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