This study deals with structural behavior of reinforced concrete pipes under various loading and support conditions by using nonlinear three-dimensional isoparametric 20-node brick elements. the computer program of three dimensional nonlinear finite element analysis of reinforced concrete structures, written by Al- Shaarbaf is utilized. The behavior of concrete is investigated by using twenty-node brick elements. The reinforcement bars are idealized as axial members embedded within the brick elements with perfect bond between the concrete and the steel curved bars in a brick element were...