ABSTRACT
The basic constituent of structural steel is iron, an element widely and liberally available over the world's surface but with rare exceptions found only in combination with other elements. The main deposits of iron are in the form of ores of various kinds which are distinguished by the amount of metallic iron in the combination and the nature of the other elements present. Iron ore is charged into the furnace with coke and limestone. To the structural designer, certain properties of steel merit special consideration. Elasticity is also exhibited by higher strength steels which do not have a defined yield point. Automatic or semi-automatic fabricating methods are applied to the production of welded plate girders which consist of two plate flanges welded to a plate web. The early forms of fire protection involved the use of a heavy encasement in concrete or brickwork, and concrete is still traditionally thought of as 'fire protection'.
