Introduction
A beam is defined as an element that is structural in nature and one that can resist load primarily by bending. Historically speaking, beams were the squared timbers, however, over the time we have witnessed beams made of a number of materials.
How Does A Beam Work?
As mentioned already, beams tackle loads by allowing themselves to bend. The bending force that is generated on a beam is due to the external loads that are being applied on the beam, beam’s own weight, span and the external reactions to the loads known as bending moment. Beams work by transferring loads to their supports and subsequently to columns, walls or girders.
Types of Beam 
- Simply supported
- Fixed
- Over hanging
- Double overhanging.
- Continuous
- Cantilever
- Trussed
Applications of Beam
- Roofs
- Frame Structures
- Tie Beam
- Bridges
Precautionary Measures 
- Make sure that the beam doesn’t crack.
- If cracks do appear they should be attended to.
- If the beam is bent permanently then it is about to fail.
- Never load a beam with more weight than what is has been designed for.
awesome explaination about of beam
Superbb
This series on basic construction topics is a good one. Short and simple intros to what these different things are.