Materials that are used for structu

Materials that are used for structural purposes should meet several requirements. In most cases it is important that they should be hard, durable, fire-resistant and easily fastened together.
The most commonly used materials are steel, concrete, stone, wood and brick. They differ in hardness, durability and fire-resistance.
Wood is the most ancient structural material. It is light, cheap and easy to work. But wood has certain disadvantages: it burns and decays.
Stone belongs to one of the oldest building materials used by man. It is characteristic of many properties. They are mechanical strength, compactness, porosity, sound and heat insulation and fire-resistance.
Bricks were known many thousands of years ago. They are examples of artificial building materials.
Concrete is referred to as one of the most important building materials. Concrete is a mixture of cement, sand, crushed stone and water.
Steel has come into general use with the development of industry. Its manufacture requires special equipment and skilled labor.
Plastics combine all the fine characteristics of a building material with good insulating properties. It is no wonder that architects and engineers have turned to them to add beauty to modern homes and offices.
All building materials are divided into three main groups:
1. Main building materials such as rocks and artificial stones, timber and metals.
2. Binding materials such as lime, gypsum and cement.
3. Secondary or auxiliary materials which are used for the interior parts of the buildings.
We use many building materials for bearing structures. Binding materials are used for making artificial stone and for joining different planes. For the interior finish of the buildings we use secondary materials.
Natural building materials are stone, sand, lime and timber. Cement, clay products and concrete are examples of artificial building materials.
2 Timber
Timber is the most ancient structural material. In comparison with steel timber is lighter, cheaper, easier to work and its mechanical properties are good. On the other hand, timber has certain disadvantages. First, it burns and is therefore unsuitable for fireproof buildings. Second, it decays.
At present an enormous amount of timber is employed for a vast number of purposes. In building timber is used too.
Timber is a name applied to the cut material derived from trees. Timber used for building purposes is divided into two groups: softwoods and hardwoods. Hardwoods are chiefly used for decorative purposes, as for paneling, veneering in furniture and some of them are selected for structural use because of their high strength and durability. In modern construction timber is often used for window and door frames, flooring, fences and gates, wall plates, for temporary buildings and unpainted internal woodwork.
Timber cannot be used for either carpenters' or joiners' work immediately it has been felled because of the large amount of sap which it contains. Elimination of this moisture increases the strength, durability and resilience of timber.
3 Stone
Stone has been used as a structural material since the earliest days.
Almost all famous buildings of classic times, of the medieval and
Renaissance periods and of the 18th and early 19th centuries were erected of stone masonry. In some places stone was used because of the scarcity of timber but in other places stone was preferred because of its durability.
The stones which are usually used for masonry work are as follows:
1. Granite is very hard, strong and durable. It is used particularly for basements, base courses, columns and steps and for the entire facades. Its colour may be grey, yellow, pink or deep red.
2. Sandstone is composed of grains of sand or quarts cemented together. Sandstones form one of the most valuable materials. The durability of sandstones depends very largely upon the cementing material. Thus, there are different kinds of sandstones. Many sandstones are exceptionally hard and are selected for steps, sills, etc. It is an excellent material for concrete aggregate.
3. Marble is a crystalline stone chiefly used for decorative purposes. White and black marbles are used for ornamental decoration where the beauty of the marble is shown to its best advantage.
4 Metals and concrete
All metals are divided into ferrous metals and non-ferrous metals. Ferrous metals include iron, steel and its alloys. Non-ferrous metals are metals and alloys the main component of which is not iron but some other good element. Metals, in general, and especially ferrous metals are of good importance in variations.
Metals possess the following properties:
1. All metals have specific metallic lustre.
2. They can be forged.
3. Metals can be pulled.
4. All metals except mercury are hard substances.
5. They can be melted.
6. In general, metals are good conductors of electricity.
These characteristics are possessed by all metals but the metals themselves differ from one another. Steel and cast iron are referred to the group of ferrous metals. Cast iron is the cheapest of the ferrous metals. It is chiefly used in building for compressed members of construction, as the supporting members. When an engineer designs a steelwork he must carefully consider that the steel frame and every part of it should safely carry all the loads imposed upon it. The steel framework must be carefully hidden in walls, floors and partitions. It is steel and metal that is employed as reinforcement in modern ferroconcrete structures. In the curriculum of the Institute there is a special course on metal structures.
Steel. There are different kinds of steel. Alloyed steel or special steel
is corrosion-resistant steel. This kind of steel is widely used in building. Stainless steel is also corrosion-resistant steel. It is used for cutlery, furnace parts, chemical plant equipment, valves, ball-bearings, etc.
Non-ferrous metals. Non-ferrous metals have the following characteristics: high electric and heat conductivity, high corrosion resistance, non-magnetic qualities, light weight.
Alumunium. This is the oldest and best known light metal. It is used in aircraft, automobile, chemical and some other industries.
Copper. Copper is the best conductor of electricity. There are different alloys with copper. An alloy of copper and tin is called bronze. This metal is often used for making various ornaments.
Buildings of reinforced concrete may be constructed with load-bearing walls or with a skeleton frame. According to the first method, the exterior walls are designed of sufficient strength to carry the loads of the girders, beams, floors and roofs which rest on them. The interior supports may consist also of load-bearing walls or of columns, but this method does not utilize the full potentialities of concrete. By the second method, the floors and roofs rest directly on exterior and interior columns or are carried on beams and girders which, in turn, rest on the columns. The walls and partitions are simple enclosures of brick or reinforced concrete supported by the beams and girders. Most concrete buildings of any size are now designed according to this second or skeleton frame method.
5 Cement: man's miracle mix
One of man's oldest building materials is finding its way into a lot of new places these days. Concrete, first discovered by the Romans, is now more widely used in construction than all other materials together.
The magic ingredient that makes concrete possible is cement, about which according to one expert more has been learnt in the past three decades than in the preceding 2000 years. Concrete is a synthetic stone which can be formed while soft into practically any shape the builder wants. Portland cement mixed with water is the paste that binds sand, gravel, clinker into an artificial rock that becomes harder as the years pass. Portland cement does not come from a place of that name; it was called Portland because Joseph Aspdin, the English builder who invented the first dependable, scientifically made cement about 1824, thought it resembled the rock excavated on the Isle of Portland on the Dorset Coast.
What's so new about cement after all these years? Several things. One item is "squeezed" concrete known technically as pre-stressed concrete. By giving concrete a big squeeze after it has hardened, builders can increase its elasticity ten times, so that it will bend under a heavy load without breaking. This is important in building bridges, viaducts and floors of large buildings.
The simplest way to pre-stress concrete is to put steel wires or rods in the concrete when it is poured.
An unusual American use of reinforced concrete is the floating highway bridge across Lake Washington. The depth of the lake made piers too expensive, so engineers built the bridge on hollow concrete pontoons anchored in place by steel cables. It is the longest pontoon bridge structure on Earth.
Until recently the aim of engineers was to make concrete with as few bubbles as possible. Now they have come up with a new concrete that has millions microscopic bubbles per cubic foot. It is made by adding an agent which foams to form the bubbles when the concrete is mixed. This concrete doesn't crack when freezing. The first "air bubble" roads were built many years ago. They have stood up under winter freezes so well that today this concrete is used for new road construction.
Another discovery is "soil cement". Several years ago road builders lacking funds found that they could mix cement with soil on the site of the road, wet it and compact it, then cover it with bitumen. The first road they built is still carrying traffic. There are miles of soil-cement secondary roads and streets today. Construction goes so fast that with modern equipment a road builder can complete a mile of soil cement road in one day.
Scientists are working on research into the behavior of cement and concrete under all kinds of conditions. Collaborating with engineers they are developing new ways

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материалы, которые используются для структурных целей должны отвечать ряду требований.в большинстве случаев, важно, что они должны быть жесткий, прочный, огнеупорных и легко скреплены вместе.наиболее часто используемые материалы стали, бетон, камень, дерево и кирпича.они отличаются твердостью, долговечности и огнестойкости.древесина является самой древней конструкционного материала.он легкий, дешево и легко работать.но дерево имеет определенные недостатки: оно горит и тлеет.камень принадлежит одному из старейших строительных материалов, используемых человеком.это характерно для многих свойств.они механическую прочность, компактность, пористость, звуко - и теплоизоляции и огнестойкости.кирпичи были известны многие тысячи лет назад.они являются примерами искусственных материалов.конкретные называют одним из наиболее важных строительных материалов.конкретные представляет собой смесь цемент, песок, щебень, и вода.стали вступать в общее пользование с развитием промышленности.производство требует специального оборудования и квалифицированной рабочей силы.пластмассовые объединить все прекрасно особенности строительного материала, с хорошими теплоизоляционными свойствами.неудивительно, что архитекторы и инженеры превратили их добавить красоты для современных домов и офисов.все строительные материалы, подразделяются на три основные группы:1.основных строительных материалов, таких, как камни и искусственные камни, древесины и металла.2.обязательный материалов, таких, как лайма, гипса и цемент.3.среднее или вспомогательные материалы, которые используются для внутренней части здания.мы используем много строительных материалов на несущие конструкции.обязательный материалы используются для искусственного камня и за участие в разных плоскостях.для отделки из здания мы использования вторичных материалов.природные строительные материалы - это камень, песок, известь и древесины.цемент, клэй продуктов и конкретные примеры искусственного строительных материалов.2 древесиныдревесина является самым древним конструкционного материала.по сравнению со стальными древесины легче, дешевле, легче работать и механические свойства хорошие.с другой стороны, древесина имеет определенные недостатки.во - первых, он горит, и поэтому пригоден для огнеупорные зданий.во - вторых, она разлагается.в настоящее время огромное количество древесины используется для огромного числа целей.в здании лесоматериалов используется тоже.лес - это имя применяется к вырезать материала, полученного из деревьев.лесоматериалы, используемые для строительных целей разделен на две группы: древесина хвойных пород и пород.древесина лиственных пород в основном используются в декоративных целях, как на обшивку veneering в мебели, и некоторые из них выбираются на структурные, поскольку их высокая прочность и долговечность.в современной строительной древесины, часто используется для окон и дверей, полов, заборы и шлагбаумы, настенные тарелки, для временных зданий и некрашеные внутренний свет.лес не может использоваться либо плотников "или участников работы сразу же он был сбит из - за большого количества SAP в нем.ликвидация этой влаги, повышает прочность, прочность и устойчивость древесины.3 камнякамень был использован в качестве конструкционного материала с первых дней.почти все известные здания классической время, в средневековье иренессанс периоды и 18 - м и в начале 19 века были возведены каменные каменщик.в некоторых местах камень используется с учетом дефицита лесоматериалов, но в других местах, камень был более предпочтительным в силу своей прочности.камни, которые обычно используются для строительных работ, являются следующими:1.гранит, очень сложно, прочных и надежных.он используется, особенно в подвалах, базовых курсов, колонны и шаги, и за весь фасад.цвет может быть серой, желтый, розовый или темно - красным.2.песчаник входят песчинки, или других сюда вместе.открыто являются одним из наиболее ценных материалов.прочность песчаника, зависит во многом от закрепления материала.таким образом, существуют различные виды песчаника.многие открыто необычайно трудно, и выбираются на шаги, порогов и т.д. это прекрасный материал для конкретного агрегата.3.мрамор кристаллический камень в основном используются в декоративных целях.белые и черные шарики используются декоративные украшения, где красота мраморных показывают все преимущества.4 металлов и конкретныхвсе металлы, делятся на черных металлов и цветных металлов.черных металлов включают чугуна, стали и сплавов.металлов и сплавов цветных металлов являются основным компонентом которого является не железный, но некоторые другие хорошие элемент.металлы, в целом, и особенно черных металлов имеют хорошее значение в вариации.металлы обладать следующими свойствами:1.все металлы, есть конкретные металлический блеск.2.они могут быть поддельными.3.металлы могут быть вытащили.4.все металлы, за исключением ртути трудно веществ.5.они могут быть растаял.6.в целом, металлы являются хорошими проводников электричества.эти характеристики которых обладают все металлы, но сами металлы отличаются друг от друга.стали и чугуна, называют