VI. Enumerate all the factors, which must be considered in foundation design.

Structural Elements of the building

Foundations

I. Memorize the following words:

a footing - основание

a pier - устой

to distort - искажаться

to extend - простираться, распространяться

to heave - вздыматься

to swell - набухать, увеличиваться

to shrink - сокращаться, давать усадку

to penetrate- проникать

to transmit - передавать

to thaw - оттаивать

uneven - неравномерный

II. Read the text

Foundations

The loads that a structure imposes, on the ground normally reach the ground through walls,

piers, or columns. Ideally, if the ground surface is a firm stratum of natural rock, able to take the loads directly without noticeable settlement, the walls, piers, or columns can simply be ended when they reach it. They can also be built up directly from it after some preliminary leveling. Unfortunately, such strata have rarely been found in the places where men have wanted to build. Therefore, some means have to be provided to spread the loads more widely to carry them down to rock or firmer ground at a lower level.

A foundation is Structure that transmits loads from a building or road to the underlying ground. A footing is a slab element that acts as the foundation, transferring loads from the superstructure to the ground.

Most foundations extend underground, and the foundations of large buildings often penetrate to the bedrock. One common type of foundations consists of walls that extend below the frost line and transfer the weight to wider footings. Other kinds of foundations include Slab-on grade foundations, pier and beam foundations and piles.

The primary dangers to a foundation are movement and uneven support. Change in ground water table is a common cause of foundation failure. Also flowing water can remove supporting soil from underneath a bridge foundation and freezing water can heave the supporting soil in one direction and then in the other direction when it thaws.

Changes in soil moisture can cause 'reactive' clay soil to swell and shrink. This swelling can vary across the footing due to seasonal changes or the effects of vegetation removing moisture. The variation in swell can cause a footing sitting on the reactive foundation soil to distort, cracking the structure over it. This is a particular problem for house footings semi-arid climates such as South Australia, Southwestern USA, Israel, and South Africa where wet winters are followed by hot dry summers. Raft slabs with inherent stiffness have been developed in Australia with capabilities to resist this movement.

When heavy structures are built in arctic areas where the ground is permanently frozen, special refrigeration units must be used to keep the pressure of the structure from melting the supporting soil.

III. Answer the following questions:

1. What is the function of foundations?

2. What types of foundations do you know?

3. What are the main clangers to foundations?

4. What factors can cause the failure of the foundations?

5. How do climatic conditions influence the choice of the foundation design?

6. How do the structural loads reach the stratum?

IV. Make cause/effect statements according to the text

cause	effect
1. The soil moisture changes	The construction	collapses
2. The level of ground water changes	The cracks occur

V. Are these statements true or false? Correct the wrong statements.

1. The loads of the structure normally reach the ground through walls, piers, or columns.

2. Only one type of foundations is used in structural design.

3. Uneven support and movement are not dangerous for foundations.

4. Changes in soil moisture can cause cracks in the construction.

5. House footings don't suffer from soil swelling in semi-arid climates.

6. When heavy structures are built in Arctic areas special refrigeration units are used.

VI. Enumerate all the factors, which must be considered in foundation design.

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