Embedded Steel Bars Simulation in Reinforced Concrete Using Three-Dimensional Finite Elements

Three methods exist to represent the reinforcement bars namely discrete representation, layered (or distributed) representation, and embedded representation. The main aim of this paper is to develop a simulation for the reinforcing steel bars in reinforced concrete using three-dimensional finite elements. The weighted residual method is used to formulate the finite element equations. Eight nodes isoparametric brick element (linear brick elements or Q8) are used to represent the concrete structures. The contribution of steel reinforcement to the stiffness matrix is achieved directly by using bar stiffness matrix, without undertaking numerical integrations that used in other methods. Since isoparametric brick elements are used in this model, the nodes of the truss element of the steel bar can be located using the global coordinates of the brick element nodes. The nodes of the truss element that represent the steel bars can be located in any location within or on the boundary of the brick element. According to that, embedded truss elements that represent the steel bars can be located in any location in the brick element, can be in any size and can be in any orientation. Moreover, the proposed method overcomes the difficulties of the numerical integrations and the computer programming.