In this paper, the influence of confinement on tensile forces in Concrete,
using fibers in the form of closed fibers (hoops), is theoretically investigated. In addition
to the resistance of tension, the hoops confine Concrete. Physical analysis is based on the
elongation of Concrete under tension. However, hoops prevent this elongation and
consequently compress the Concrete. Assumptions are made to simplify the complex
analysis of the hoop within the Concrete Structure. The theoretical results indicate that
tensile force and stress within the hoop are not uniform and shear force direction is not
constant. Final formulations depict distribution of tensile force, normal stress and shear
stress in circumference of hoop with respect to the axis of tensile force imposed on the
Concrete. These formulations are capable of including strength and ductility of Concrete
and hoop materials. Theoretical behavior of hoop and fiber within a continuum reveals
that fiber is under shear and bearing stresses while a hoop is under normal tensile stress.
However, due to confinement, the Concrete Structure reinforced with hoop possess higher
strength and ductility than the Concrete Structure reinforced with fiber.