In many buildings and bridges, it is common to have a concrete slab supported by steel beams. If the steel beams are connected to the concrete slab in such a way that the two-act as one unit, the beam is called as composite beams. Composite beams are similar to concrete T-beams where the flange of the T-beam is made of the concrete slab and the web of the T-beam is made of the steel section.

Advantages of composite beams are

1- Increased strength for a given cross-sectional dimension.

2- Concrete and steel are utilized effectively.

3- Good fire resistance in the case of concrete-encased beams.

4- Corrosion protection in encased beams.

5- Significant economic advantages over either pure structural steel or reinforced concrete alternatives.

6- Identical cross-sections with different load and moment resistances can be produced by varying steel thickness, concrete strength, and reinforcement. This allows the outer dimensions of a beam to be held constant, thus simplifying the construction and architectural detailing.

7- Concrete encased steel beams are also stronger in resisting impact loads.

8- More economical steel section is used in composite construction than conventional non-composite construction for the same span and loading.

9- The depth and weight of the steel beam required is reduced. So, the construction depth also reduces increasing the headroom of the building.

10- Composite beams have higher stiffness, thus it has less deflection than steel beams.

11- Composite beams can cover for large space without the need for any intermediate columns.

12- Composite construction is faster because of using rolled steel and pre-fabricated components than cast-in-situ concrete.

13- Encased steel beam have a higher resistance to fire and corrosion.

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