Continuous beam

When a beam runs across several supports it is said to be "continuous". Such a beam can be of smaller dimensions than one supported at the ends only since the effective span is less. If the beam is discontinuous, there is no bending effect at the supports, and the ends are free to move. Each part, therefore, is not helped by its neighbours.
In choosing whether to make a beam continuous or not the designer takes several factors into account. For example, savings on beam section have to be balanced against the costs of the supports. A very long continuous beam may involve large changes in overall length with variations in temperature.