ABSTRACT
With the publication of the second generation of EN1992-1-1, many changes are introduced in the shear design of concrete elements. Among those, the implementation of prestress in the shear resistance in the cracked regions of prestressed elements without transverse reinforcement has changed, since this is now calculated according to the Critical Shear Crack Theory. To verify the new design proposals, a series of prestressed beams are tested, complemented by a virtual simulation of the experiments. In this work, the shear resistance of one prestressed beam is simulated numerically and compared with the experimental outcome. The beam is modelled using the Lattice Discrete Particle Model, an advanced non-linear discrete element method that explicitly models the aggregates and the cement-mortar matrix. This makes it particularly well-suited for applications where the material heterogeneity and cracking behaviour play a dominant role, such as in shear failure.
Because of the heterogeneous modelling, the model is a mesoscale model and needs thorough calibration. To this extent, experimental characterisation tests are carried out to quantify the key mechanical properties of the concrete. These properties include the bending and splitting tensile strength, compressive strength, Young’s modulus and fracture energy. These characterisation tests are also simulated virtually to perform the calibration of the mesoscale parameters.
Finally, a large-scale beam test is modelled and the load-displacement diagram is compared with the virtually obtained diagram. Together with the global behaviour, the local cracking behaviour is compared by experimental measurements and the final numerical and experimental cracking pattern is compared. Additionally, the obtained shear resistance is compared with the analytically obtained resistance predicted by the CSCT. These results contribute to the validation of the design provisions of Eurocode 2 and showcase the ability of LDPM to simulate experimental outcomes.
