Expansion joints and building movement joints may be referred to by other names such as expansion joints. Essentially, buildings move, even small buildings have micro movements. But large building construction assemblies such as bridges, in the case of the photo below, and on many other types of structures all all face typical movement. Some of the movement is negligable and has little consequence, other types of typical movement can cause building cracking and even building systems failure. We we install building movement joints so that the building may absorb and move as needed by the laws of physics, without significant damage.
The issue of building movement is often discussed or presented as single source type of problem, People generally focus on building movement issues related to temperature differentials. However, buildings move for a variety of reasons. Other causes of building movement include: earth movements, wind forces, subsoil differential settlement, deterioration of building load path elements.