What is composite construction?
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An outstanding feature of efficient, innovative structures is very often an ideal combination of various different building materials. The favourable combination of steel, with its high tensile strength and ductility, and concrete, with its high compressive strength and good resistance to corrosion, has long been recognized in structural concrete construction. With the method of composite construction it is now possible to combine the positive features of steel construction and structural concrete, without having to accept the drawbacks. This means that a steel skeleton structure is combined with concrete parts so that a joint bearing effect is created. The steel beams bear the tensile forces, while the concrete bears the compressive forces and provides fire protection.

Figure 1: Principle of compositebeam (schematic diagram)

 
  Obvious advantages of composite construction with steel and concrete:
· High loading capacity at low construction heights (important for building construction)
· For bridges with spans ranging from abt. 40 to 80 m often the most cost-effective solution
· Wide spans possible, thus allowing large areas free of columns (important e.g. for multi-storey car parks)
· High ductility of the structure, favourable in case of seismic stress
· Simplicity of alteration to installations through clamping connections fitted to the steel beams
· Good fire protection through encased steel beams or beams with concrete cores
· Quick assembly similar to 100 % steel construction; the steel skeleton serves as a working platform
· Easy to dismantie, steel and concrete are easy to separate
· Secure connection between steel and concrete with the help of tested and certified welded-on shear connectors