A tension-relieving apparatus for reducing a level of tension in a structure. The tension-relieving apparatus includes a housing, a piston, a spacer member and a heat source. The housing has a wall member that defines a piston cavity. A rod aperture is formed in a first end of the wall member. The piston assembly has a rod and a piston. The rod extends through the rod aperture. The piston is disposed in the piston cavity and is coupled to an end of the rod. The spacer member is disposed in the piston cavity and is coupled to the piston assembly. The spacer member is transformable between a first condition and a second condition, with the first condition maintaining the piston at a first distance from the first end of the housing. The heat source is coupled to one of the housing, the piston assembly, and or the spacer member and provides heat to selectively cause the spacer member to transform to the second condition wherein the spacer member at least partially melts to permit the rod to advance toward the first end of the housing. Advancement of the piston toward the first end of the housing relieves a predetermined portion of the tension in the structure.