Vibrations of concrete beams under far-field blasts: A comparative study of two continuum-based approaches

Abstract

Existing methods for analysing concrete beams under blast loads are predominantly numerical or simplified analytical models with a single degree of freedom. In this paper, two novel continuum-based approaches are presented to address this gap. The first approach, while analytically elegant, relies on assuming a uniform crack distribution. This unrealistic distribution produced results quite in disagreement with experiment. That limited its application to benchmarking purposes. The second approach, a more sophisticated implicit central difference method, incorporates a more realistic crack pattern approximation. This method was validated against experimental data for far-field and near-field blast scenarios, demonstrating good agreement with experiment. Numerical experimentation revealed the significant impact of the crack distribution on the maximum displacement of the beam. The results given by the first analytical approximation demonstrated that the maximum vibration amplitudes obtained when such unrealistic spatial distributions of cracks are assumed would hover around a tenth of the real ones. However, the second method, with its realistic crack modelling, closely captured the observed experimental behaviour, offering a reliable and efficient tool for the analysis of concrete beams under blast loads.