2020-05-25
383
The major elements of a building include the following: the foundation, which supports the building and provides stability; the structure, which supports all the imposed loads and transmits them to the foundation; the exterior walls, which may or may not be part of the primary supporting structure; the interior partitions, which also may or may not be part of the primary structure; the environmental-control systems, including the heating, ventilating, air-conditioning, lighting, and acoustical systems; the vertical transportation systems, including elevators, escalators, and stairways; communications, which may include such subsystems as intercommunications, public address, and closed-circuit television, as well as the more usual telephone-wiring systems; and the power, water supply, and waste disposal systems.
The structural design of a building depends greatly on the nature of the soil and underlying geologic conditions and modification by man of either of these factors.
Ground Conditions. Soils that have been modified in some way often perform differently, especially when other soil has been added to or mixed with existing soil, or when the soil has been made wetter or drier than normal, or when cement or chemicals such as lime have been added. Sometimes the soil under a proposed building varies so greatly over the entire site that a building simply cannot be constructed safely or economically.
Soil and geologic analyses are necessary, therefore, to determine whether a proposed building can be supported adequately and what would be the most effective and economical method of support.
Types of Foundations. The most common types of foundation systems are classified as shallow and deep. Shallow foundation systems are several feet below the bottom of the building; examples are spread footings and mats. Deep foundations extend several dozen feet below the building; examples are piles and caissons. The foundation chosen for any particular building depends on the strength of the rock or soil, magnitude of structural loads, and depth of groundwater level.
The most economical foundation is the reinforced-concrete spread footing, which is used for buildings in areas where the subsurface conditions present no unusual difficulties. The foundation consists of concrete slabs located under each structural column and a continuous slab under load-bearing walls.
Mat foundations are typically used when the building loads are so extensive and the soil so weak that individual footings would cover more than half the building area. A mat is a flat concrete slab, heavily reinforced with steel, which carries the downward loads of the individual columns or walls.
Piles are used primarily in areas where near-surface soil conditions are poor. They are made of timber, concrete, or steel and are located in clusters. The piles are driven down to strong soil or rock at a predetermined depth, and each cluster is then covered by a cap of reinforced concrete. A pile may support its load either at the lower end or by skin friction along its entire length. The number of piles in each cluster is determined by the structural load and the average load-carrying capacity of each pile in the cluster.
Caisson foundations are used when soil of adequate bearing strength is found below surface layers of weak materials such as fill or peat. A caisson foundation consists of concrete columns constructed in cylindrical shafts excavated under the proposed structural column locations. The caisson foundations carry the building loads at their lower ends, which are often bell-shaped.
New vocabulary:
Foundation – фундамент structure - здание, сооружение
load – нагрузка to transmit to – передавать
exterior walls - наружные стены interior partition - интерьерная отделка
communication – связь environmental-control system – система контроля
power – энергия состояния окружающей среды
water supply - снабжение водой vertical transportation system - система вертикальной
waste disposal system – канализация транспортировки
soil – почва to propose - предполагать, строить планы
adequately – адекватно shallow - мелкий, поверхностный
deep – глубокий bottom – дно
extensive – обширный pile - свая, столб
caisson – кессон magnitude – величина
depth – глубина groundwater level - уровень почвенных вод
slab – плита subsurface – находящийся, лежащий под поверхностью
load-bearing wall - несущая стена cluster – группа
friction – сцепление peat – торф
cylindrical shaft -цилиндрическая колонна to excavate - копать, выкапывать
Answer the following questions.
1. What elements of building do you know?
_________________________________________________________________________________________________________________________________________
2. What do they include?
_________________________________________________________________________________________________________________________________________
3. What factors does the structural design of a building depend on?
_________________________________________________________________________________________________________________________________________
4. Why is it necessary to determine the nature of the soil?
_________________________________________________________________________________________________________________________________________
5. What are the most common types of foundations?
_________________________________________________________________________________________________________________________________________
6. What is the most economical foundation? What does it consist of? When is it used?
_________________________________________________________________________________________________________________________________________
7. What is the mat foundation? What does it consist of? When is it used?
_________________________________________________________________________________________________________________________________________
8. What is pile? What does it consist of? When is it used?
_________________________________________________________________________________________________________________________________________
9. What is caisson foundation? What does it consist of? When is it used?
_________________________________________________________________________________________________________________________________________
2. Find the English equivalents:
структурный дизайн здания
__________________________________________________________________
характер почвы
__________________________________________________________________
геологическое состояние
__________________________________________________________________
видоизменение
__________________________________________________________________
определить более эффективный и экономичный метод поддержки
__________________________________________________________________
обычный
__________________________________________________________________
опора
__________________________________________________________________
Translate the sentences into English.
1. Фундамент - часть сооружения, преимущественно подземная или подводная, которая служит его опорой, воспринимает действующие на сооружение нагрузки и передает их на основание.
_________________________________________________________________________________________________________________________________________________________________________________________________________
2. В промышленном и гражданском строительстве для стен и колон широко применяются сборные фундаменты из заранее заготовленных бетонных и железобетонных элементов.
_________________________________________________________________________________________________________________________________________________________________________________________________________
3. Различают несколько типов фундаментов.
_____________________________________________________________________
4. Их выбор зависит от характера почвы и ее геологического состояния.
________________________________________________________________
5. Исходя из этих факторов выбирают мелкие или глубокие фундаменты.
________________________________________________________________
