This thesis aims to deepen the comprehension of shear failure of impact-loaded reinforced concrete beams, by performing further numerical studies to complement previous research in the area. The study was conducted in cooperation with KTH Royal Institute of Technology and AFRY. The study was conducted to address the existing knowledge gap concerning shear failure modes of concrete structures subjected to impact loads. Initially, a literature study was performed regarding dynamic shear failure and dynamic material response during impact loading, as well as basic theoretical concepts for non-linear finite element modeling of concrete and steel.

Primarily,the thesis built upon and utilised the results from a previously executed experimental study at KTH, performed by Abdalnour and Saliba (2023) and Peterson et al. (2024). The experiment evaluated drop-weight impact tests on reinforced concrete beams where the striker transferred an impulse to the beam at impact. These experimental results were used to validate a numerical dynamic model developed in the finite element software ABAQUS.

The dynamic model ultimately functioned as a fundamental base when proceeding to the main goal of this thesis,which was to perform a parameter study regarding interesting parameters that could affect the outcome of the results. The analysis investigated three different impulse rates, three different impulse magnitudes, and two different boundary conditions, corresponding to a simply supported and a fixed beam. The study included an evaluation of how the impulse rate, impulse magnitude, and boundary conditions influenced the shear failure modes of the beam.The obtained results were further presented and discussed focusing on the support reaction forces, mid-point deflection, crack propagation and damage modes. Further, a comparative analysis regarding the damage modes was performed, in addition to a concluding strain rate analysis.

Finally, stemming from the parameter study, several conclusions could be drawn. Firstly, both an increased impulse rate and impulse magnitude, regardless of boundary conditions, result in a higher mid-point deflection and support reaction forces. Secondly, an increased impulse rate showed to change the failure mode, whereas an increased impulse magnitude only increases the severity of the damage, without changing the mode. Lastly, it was stated that fixed beams are mainly governed by shear-dominated damage, whilst simply supported beams are governed by a combination of dominating shear and flexural damage.