Approach for Reinforcement Design in Reinforced Concrete Structures Based on 3-Dimensional Stress Field

This paper explores an approach for the design of reinforced concrete structures based on 3-dimensional (3-D) stress fields instead of the conventional axial loads, bending moments etc. The reinforcements in 3 mutually perpendicular directions which can adequately and optimally resist the direct stresses and shear stresses are determined. As a first attempt to the problem, the simplest ‘Plasticity (Equilibrium) Truss Model’ is used by which only force equilibrium is considered. Though strain compatibility is not taken into account in the formulation, the approach is compatible with the common reinforced concrete design codes currently adopted worldwide. Furthermore, in the present approach, the stresses provided by concrete and steel are limited to constant ‘design strengths’ and are assumed to be perfectly ‘plastic’, ie stay at the constant design strength values when these values are reached. The proposed method can hence comply with the design codes currently adopted in Hong Kong and other countries.