Simulation of shear-type cracking and failure with non-linear finite-element method

Today, the non-linear finite-element (FE) method is commonly used by practising engineers. Simulating the shear behaviour and shear failure of reinforced concrete structures, using three-dimensional non-linear finite-element methods, has shown higher load-carrying capacity due to favourable load distribution, compared to conventional analyses. However, the modelling method for reinforced and prestressed concrete members subjected to shear and torsion has not been generally verified. Therefore, the method needs to be investigated further and confirmed to be practically reliable. The aim of this project is to develop, improve and verify a method to simulate the shear response of reinforced and prestressed concrete members. The method should be applicable for large structures, for example box-girder bridges, subjected to various load actions. Experiments with panels loaded in shear and beams loaded in bending, shear and torsion are simulated by using non-linear FE analysis. The results showed that four-node curved shell elements with embedded reinforcement could simulate the shear response. It is well known that the shear sliding capacity is larger than that which can be explained by the reinforcement contribution determined from a truss model. This increase is due to dowel action and aggregate interlock, and has been accounted for in the past by modifying the concrete tension response in models—for example, according to the modified compression field theory (MCFT). Results from the analyses show that without any modification, the capacity was underestimated and the average strains—that is, the crack widths—were overestimated. On the other hand, if the concrete contribution to the shear capacity was considered with the expression from MCFT, the capacity was in many cases overestimated and the average strains underestimated.