STEEL - Materials for Civil and Construction Engineers - page 86

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STEEL
The use of iron dates back to about 1500 B.C. when primitive furnaces were
used to heat the ore in a charcoal fire. Ferrous metals were produced on a
relatively small scale until the blast furnace was developed in the 18th cen-
tury. Iron products were widely used in the latter half of the 18th century
and the early part of the 19th century. Steel production started in mid-1800s
when the Bessemer converter was invented. In the second half of the 19th
century, steel technology advanced rapidly due to the development of the
basic oxygen furnace and continuous casting methods. More recently,
computer-controlled manufacturing has increased the efficiency and re-
duced the cost of steel production.
Currently, steel and steel alloys are used widely in civil engineering ap-
plications. In addition, wrought iron is still used on a smaller scale for
pipes, as well as for general blacksmith work. Cast iron is used for pipes,
hardware, and machine parts not subjected to tensile or dynamic loading.
Steel products used in construction can be classified as follows:
1. structural steel for use in plates, bars, pipes, structural shapes, etc.
(Figure 3.1)
2. fastening products used for structural connections, including bolts,
nuts and washers
3. reinforcing steel (rebars) for use in concrete reinforcement (Figure 3.2)
4. miscellaneous products for use in such applications as forms and pans
Civil and construction engineers rarely have the opportunity to formu-
late steel with specific properties. Rather, they must select existing prod-
ucts from suppliers. Even the shapes for structural elements are generally
restricted to those readily available from manufacturers. While specific
shapes can be made to order, the cost to fabricate low-volume members is
generally prohibitive. Therefore, the majority of civil engineering projects
are designed using standard steel types and structural shapes.
Even though civil and construction engineers are not responsible for for-
mulating steel products, they still must understand how steel is manufactured