Expansion Joint

Concrete is not an elastic substance and therefore it does not bend or stretch without failure. However, concrete moves during expansion and shrinkage, due to which the structural elements shift slightly.

Expansion joints are structural components designed to provide smooth passage over the gap between adjacent sides of a deck joint, while also permitting relative translation and/or rotation of the two sides of a bridge deck (deck movement joint).

Generally speaking, a deck movement joint is a structural discontinuity between two elements, at least one of which is a deck element. It is intended to permit relative translations and rotations as a result of the following: elastic shortening from pre-stressing, displacement of the structure under load, thermal expansion and contraction of the superstructure, concrete shrinkage or creep, or any other action the desk is subjected to.