Unit 8. Strip foundations
Vocabulary.
Pier – опора
Artificial – искусственный
Rocks – камни, порода
Negligible – несущественный
Compaction – уплотнение
Bed - основание
The foundation of a building is that part of walls, piers and columns in direct contact with and transmitting loads to the ground. The building foundation is sometimes referred to as the artificial, and the ground on which it bears as the natural foundation. Ground is the general term for the earth’s surface, which varies in composition within the two main groups, rocks and soils. Rocks include hard, strongly cemented deposits such as granite and soil; the loose, uncemented deposits such as clay. Rocks suffer negligible compression and soils measurable compression under the load of buildings.
The size and depth of a foundation is determined by the structure and size of the building it supports and the nature and bearing capacity of the ground supporting it.
Strip foundations consist of a continuous strip, usually of concrete, formed centrally under load bearing walls. This continuous strip serves as a level base on which the wall is built and is of such a width as is necessary to spread the load on the foundations to an area of subsoil capable of supporting the load without undue compaction. Concrete is the material principally used today for foundations as it can readily be placed, spread and leveled in foundation trenches, to provide a base for walls, and it develops adequate compressive strength as it hardens to support the load on foundations. Before Portland cement was manufactured, strip foundations of brick were common, the brick foundation being built directly off firm subsoil or built on a bed of natural stones.
The width of a concrete strip foundation depends on the bearing capacity of the subsoil and the load on the foundations. The greater the bearing capacity of the subsoil, the less the width of the foundation for the same load.
Answer the questions:
1. What is meant by “artificial foundation” and “natural foundation”?
2. What do the size and depth of a foundation depend on?
3. What function does a continuous strip of a foundation perform?
4. What building material is used for foundations and why?
5. What is the width of a foundation determined by?
Exercises:
1) Decide whether the following statements are true or false:
1. Soils suffer negligible compression under the loads of building.
2. The structure and size of the building determine the depth of the foundation.
3. A continuous strip is usually made of brick.
4. Strip foundations of brick used to be built on a bed of natural stones.
5. The width of the foundation depends on the size of a building.
2) Match the combinations from the left with their Russian equivalents:
| 6. Strip foundation 7. Bearing capacity 8. Compressive strength 9. Foundation trench 10. Uncemented deposit | f) Несущая способность g) Траншея под фундамент h) Сыпучий слой i) Ленточный фундамент j) Прочность при сжатии |
3) Guess the word by its definition:
1. Small blocks of clay used in building
2. A weight or source of pressure borne by someone or something
3. An artificial building material made by mixing cement and various aggregates
4. A solid support designed to sustain vertical pressure
5. The stratum of earth or earthy material directly under the surface
4) Open the brackets and put the verbs in a correct form:
1. The foundation of a building (transmit) loads to the ground.
2. The ground sometimes (call) the natural foundation.
3. The bearing capacity of the ground (determine) the size and depth of a foundation.
4. Brick foundations (use) before the invention of concrete.
5. The brick foundation (build) directly off firm subsoil.
References:http://civilconstructiontips.blogspot.ru/2011/06/foundation-construction-strip.html