In analysis of reinforced and prestressed concrete shells, the reliable numerical models must include the effects of normal and shear stresses. The sufficiently reliable, simple and practically acceptable numerical model that would include the simultaneous effects of the normal and shear stresses on the failure of concrete shell is still the goal of many researches. In this paper, the previously developed numerical model for the analysis of reinforced and prestressed concrete shells under short-term and long-term loading [1] was improved by including the effects of transverse shear stresses on the shell failure. The 9-node degenerated shell element with enhanced membrane and shear locking, with the layered material model through the thickness of the shell, was used. The reinforcement was modelled as a separate layer of an adequate thickness and the distance from the mid-surface of the shell. For the in-plane shell normal and shear stresses, the concrete yield criterion was defined as a function of the principal normal stresses and the concrete failure criterion as a function of principal normal strains. The fixed orthogonal crack model was used. To include the effect of transverse shear stresses on shell failure, the yielding criterion for concrete and longitudinal reinforcement was defined by relation of transverse shear stresses and normal stresses in two mutually perpendicular vertical planes. Separate failure criterion for concrete and reinforcement was defined as a function of strains, similarly as for the stresses. A linear distribution of shear strain over the shell thickness was used. To calculate the limit strength of shell, the total redistribution of shear stress was assumed. The total transverse shear bearing capacity of the shell cross-section is obtained by summing the concrete and reinforcement contribution. The developed numerical model and appropriate software were verified on the preformed experimental tests. Further verifications of presented model are needed. |