Ответьте на вопросы к тексту.

1. How strong is toughened glass?

2. Why is it so strong?

3. How is toughened glass made?

4. What is an important reason for its selection?

5. Why does toughened glass not crack due to temperature dif­ferences?

6. What are the disadvantages of toughened glass?

7. Where is toughened glass used in buildings?

Лексические упражнения

Упражнение 1. Переведите на русский язык приведенные ниже слова:

buckling (n.), shape (v.), support (n.), hang (v.), ordinary (adj.), elevation (n.), drill (v.), selection (n.), finish (v.), fact (n ).

Если Вы не знаете слово, найдите его в словаре. Выпишите из словаря то значение слова, в котором оно использовано в тексте.

Упражнение 2. Найдите перевод слов списка А в списке В.

A закалённый раз сжатие преднапряжение изгиб избегать опора резать происходить растрескиваться

B accept significant strong crack way break compression prestress apply bending

A принимать важный случай недостаток разбиваться потеря быстро прочный прилагать образ, способ

B time toughened avoid case cut disadvantage loss rapidly take place support

Упражнение 3. Напишите предложения с каждым из перечисленных ниже слов:

compare - compared to - comparable

select - selection

Текст C

FABRIC

Fabric structures have been in use for a very long time as temporary forms of construction. The important characteristics of fabric structures are their flexibility in bending, although the forces that are developed in supports and foundations by fabric structures can be very large. Fabrics require different methods of design compared to the large majority of building structures which are rigid and cannot change shape when the loads change.

Fabrics may be made of mineral fibres, such as glass, organic fibres such as cotton, metal fibres such as stainless steel, or synthetic fibres. A film or coating is usually applied to a fabric so as to improve its properties. A mesh may be used as reinforcement to plastic film. In the latter case the mesh is usually sandwiched between two layers of film and is then known as a reinforced film. Important general characteristics of fabrics and fabric structures compared to other building materials and structures are as follows:

Fabric has moderate to high tensile strength but no effective compressive strength. The strength of the fabric depends mainly on the fibre which is used.

Fabric has a low or zero shear modulus, that is, the material can be made that shears with little or no effort. A fabric which does possess shear stiffness is less tolerant of errors in the design of a structure that is made from it and less easily adapts its shape to changes in load.

Fabric has low weight and a very high strength to weight ratio.

Fabric which is made from synthetic materials loses strength when it is loaded over a period of time. An increase in temperature also causes a loss of strength. A problem with some fabrics, especially fabrics that are made from synthetic fibres, is creep, that is, the constant increase in length of the fabric, under a constant load. Temperature and humidity can increase the creep of some materials.

Fabrics are generally elastic materials. At high load they show some plasticity, that is, they have a permanent extension even after the load is removed. The plasticity is influenced by the rate of loading.

Fabrics can be made reasonably durable, that is reasonably resistant to tears. Tears can exist in a fabric under stress for a long period of time.

Fabric structures may be erected in low temperature conditions. They may also be designed for very quick erection.

The dimensional stability of a coated fabric, that is, the degree to which it changes its dimensions over time and under different conditions depends mainly on the fibre. On the other hand the light transmission, fire resistance, permeability, weathering and durability will depend mainly on the coating in use.

High temperatures decrease the strength and increase the stretch of fabric. On the other hand, low temperatures decrease stretch of the fabric but make it easier for tears to develop. The qualities of most fabrics will not become worse to any significant extent in the range of temperatures from at least - 40°C (- 40°F) to + 60°C (+ 140°F).

Notes:

cotton n. хлопок

dimensional stability стабильность размеров

film n. плёнка

majority n. большинство

mineral fibre минеральное волокно

organic fibre органическое волокно

shear modulus модуль упругости при сдвиге

shear stiffness жёсткость при сдвиге

synthetic adj. синтетический

tear n. разрыв, разрез

zero adj. нулевой