Axial expansion joints are designed to accept movements of extension and compression in the axis direction. The length of expansion joint in neutral position is called free length. The longest service life is achieved by exploiting the axial shift in both directions as extension (+Δax) and compression (-Δax). When it is known that movement will be in one direction, to utilize the complete all available movement we propose to install expansion joint under “prestress”. The expansion joint service life depends on correct installation.