Hazard evaluation framework for large yield explosions in urban environments: A case study of Beirut explosion

Abstract

The Beirut explosion is one of the largest yield ammonium nitrate explosions in recent years, causing massive destruction and becoming a valuable case for explosion analysis. Compared with general post-disaster evaluation methods, e.g., on-site investigation and high-resolution satellite imagery, the numerical simulation approach can provide decision-makers and rescue workers with intuitive and visualized assessment results. Additionally, it can also serve as an effective tool to guide the architectural planning and blast-resistant design of building structures. However, due to the large dimension of urban numerical models, simulating explosions in complex urban blocks has low efficiency, often costing days to ensure accuracy. At present, based on the finite element analysis software AUTODYN, a framework to evaluate the post-explosion damage in city blocks is proposed, which is composed of the geospatial data, efficient numerical simulation approach, and damage evaluation principles. Subsequently, the detailed process of the numerical simulation approach is given, and it integrates the multi-stage method, symmetrical modelling, optimized graded mesh size, mapping, and mesh un-refinement technique, to reduce the number of mesh cells and increase the computational efficiency. Furthermore, the applicability of the numerical simulation approach in more complex environments is verified through two typical block explosion tests. Finally, the Beirut explosion is reproduced using the geospatial data obtained from OpenStreetMap, and the evaluation results are compared with field survey reports, satellite image analysis, and related numerical simulations. It is found that the proposed framework can quickly and effectively predict and evaluate the actual explosion accidents in the city environment.