That property of a material that returns it to its former shape after distortion. It is quantified by the stress that would be needed to cause a distortion equal to the original dimension. For most materials this is a theoretical figure, as fracture would occur at well below that stress. All materials behave elastically for a limited stress range; plastic distorsion occurs when this is exceeded.
The measure of elasticity, the elastic modulus , for the materials used in a bridge, is of importance in design calculations. Tables of values of the elastic moduli are available for materials commonly used. Usually, the letters E, G and K represent direct, transverse and bulk moduli respectively.