Ultimate Limit State Design of three-dimensional reinforced concrete structures: a numerical approach

Abstract : This contribution is addressing the evaluation of the ultimate bearing capacity of massive reinforced concrete structures. It is based on the finite element implementation of both the lower bound static and upper bound kinematic approaches of yield design, adopting the well-known Rankine criterion for modelling the three-dimensional strength properties of plain concrete, while the reinforcing bars are treated by means of an extended homogenization method. Both yield design approaches lead to optimization problems which are solved by resorting to Semi-Definite Programming (SDP) techniques. The whole computational procedure is finally applied to the design of a bridge pier cap, leading to a fairly narrow bracketing of the exact failure load of this kind of structure.