A joint assembly for controlling fractures along a fracture axis in a monolithic pour concrete structure is provided. The concrete structure is defined by a first edge form section and a generally opposed second edge form section. The joint assembly is characterized by a suspension line extending between the first edge form section and the second edge form section, and a fracture inducing sheath suspended therefrom within the concrete structure. The sheath may define an elongate slit that exposes an internal channel that the suspension line traverses. Additionally, a method for forming a control joint in a monolithic pour concrete structure via the joint assembly is provided.