Abstract :
[en] The wide majority of reinforced concrete structures are made of structural 1D or 2D elements such as beams, columns, slabs or walls, for which design methods are well known since decades, largely detailed in the literature such as EC2 or FIB Model Code [1, 2], and based on the fact that the knowledge of internal forces (moments, axial and shear forces) naturally lead to the values of the reinforcement.
However, a minority of structures is characterized by a more or less complex three-dimensional geometry, for which a FEM analysis with 3D finite elements must be done, giving, as a result of the computation, the values of stresses inside de volume and not any more the values of internal forces. Those structures can be dams, underground foundations stabilizing structures highly subjected to wind, but also others, such as support structures for windturbine towers.
This approach does not allow the application of usual rules of the organic calculation based on the knowledge of the internal forces. Some models are available in the literature, but they require some attention concerning the compatibility of the numerical solutions with the way reinforcement is practically placed. For instance, existing models assume that one can place variable percentage of reinforcements everywhere inside the volume, which is practically hard to perform, as reinforcement is generally placed along the faces of the volumes and transversely.
The paper enumerates and summarizes the existing methods allowing calculating the reinforcement inside 3D massive structures using stress analysis, and then investigates how restrictions linked to the practically compatible position of the reinforcement inside the volumes can be taken into account.
