This statement was developed by the Public Health Nursing Definition Document Task Force. under the direction of the leadership of the Public Health Nursing Section of the American. Public Health Association. The statement was adopted by the Public Health Nursing Section.
A Universal Expansion joint is an assembly containing two bellows connected by a centre pipe and equipped with tie rods. Universal Expansion joints are mainly used to absorb any combination of the three basic movements in the piping system. (Axial, Lateral, Angular).
As you stated, they control where the concrete will crack. An expansion joint is done by putting expansion material in before the concrete is poured. the material is usually 1/2 to 1 thick, depending on what is needed and allows the concrete to expand and shrink during warm or cold climate changes.