Текст B. High strength connections are much easier made between steel components than between timber and precast concrete ones

High strength connections are much easier made between steel components than between timber and precast concrete ones. Con­nections in steel can be made by welding or bolting. They are a significant proportion of the total cost of a steel structure. Normal jointing methods allow dimensional errors in production or construction of the steelwork. A cheaper and easier connection may be made if the joint is not required to be a fixed one. The experiments showed that high quality of a steel joint resulted both from the strength of steel and from its ductility.

Most jointing methods are improved by use of a material which has such a combination of strength and 'plasticity' and this accounts for the use of steel for connections in wood and precast concrete and, often, for the initial choice of a steel structure.

Convenient connection methods and a high strength to weight ratio make steelwork suitable for prefabrication and fast erection on site. However the size of prefabricated components is limited by the means of transport to site and sometimes the capacity of cranes on site.

Steel is dimensionally stable although it is subject to temperature movements. In general a typical single storey building of simple shape with steel columns would require a movement joint at about 50m (160ft) intervals.

Notes:

ductility n. вязкость, ковкость

jointing n. соединение

prefabrication n. изготовление и/или монтаж сборных конструкций

temperature movement температурное изменение

Ответьте на вопросы к тексту.

1. How can connections in steel be made?

2. What do normal jointing methods allow?

3. What does high quality of a steel joint result from?

4. What do these qualities of a steel joint account for?

5. What is the use of prefabricated components limited by?

6. What do steel structures require?

7. Why do they require it?