There are some notes the student made after reading the text "Foundations". Did he remember everything right? Read his notes and correct them if necessary.
The loads that a structure imposes on the ground normally reach the ground through walls, piers, or columns.
Foundations are strong bases of buildings, usually lying below ground level, on which they are built up.
According to the old classification, foundations can be divided into spread (shallow) and deep.
Box footings provide foundations equal to the whole area of the substructure.
Deep excavation is necessary for piling.
For tall buildings grillages of timber beams were used.
Buoyancy principle means creating open basements below ground level of sufficient volume to displace a weight of earth.
Match the beginnings of the sentences (1 – 4) to their ends (a – d) using the information from the text.
An ideal stratum have rarely been found ... .
Shallow foundations spread the load fairly near the surface… .
These piles, hammered into the ground, acted as ... .
The heaviest reinforced-concrete piles. ... .
The new requirements for tall buildings were mainly met... .
columns, transmitting part of the load to firmer ground at the foot;
simply by providing each wall, pier, or column with a substantially wider base;
are nowadays cast in situ in prebored holes;
in the places where men have wanted to build;
by the substitution of grillages of steel beams for the less efficient earlier spread footing.
Define the type of the given foundations.
Now you have learnt some more facts about foundations. Can you answer the following questions?
1. How do the loads reach the ground?
2. What is an ideal stratum for a building?
3. What are the types of foundations according to the current classification?
4. What was used for deep underwater foundations?
5. What is used instead of spread footing?
6. How can you describe the buoyancy principle?
Your friend is revising for his examination. He asks you to help because he doesn't know the meaning of some terms. Explain these terms.
The strip footing, pile foundation, mat foundation, the buoyancy principle.
Read and translate text 2 using a dictionary if necessary.
Caissons
The word "caisson" is derived from the French word meaning "case". In civil engineering a caisson may be defined as a large watertight box used to excavations of foundations and the construction of substructures. It is an integral part of the structure. This box or caisson may be "open", without a bottom or may be excluded by air pressure, and the box becomes a pneumatic caisson. This was a development of the earlier cofferdam — a wall within which, after pumping out the water, it was possible to excavate and then build the base of the pier in the dry. The ordinary open caisson consists of a box with cross walls. Sometimes the caisson is constructed of reinforced concrete or a steel cylinder.
Say if its true or false. Use the following expressions: "That's right" or "That's true", "That's wrong" or "According to the text…".
The word "caisson" isn't of English origin.
In construction engineering a caisson is defined as a small watertight box applied to exclude water during the assembly work.
This box may be with or without a bottom.
If the box is inverted, the water may be excluded by water pump.
The common open caisson has usually a box with cross walls.