Ricardo Daniel AMBROSINI
Evaluation of the dynamic response of structures and soils subjected to blast loading using hydrocodes
Abstract: Due to different accidental or intentional events, related to important structures all over the world, explosive loads have received considerable attention in recent years. The design and construction of public buildings to provide life safety in the face of explosions is receiving renewed attention from structural engineers. For many urban settings, the proximity to unregulated traffic brings the terrorist threat to or within the perimeter of the building. For these structures, blast protection has the modest goal of containing damage in the immediate vicinity of the explosion and the prevention of progressive collapse. In this sense, computer programs simulations could be very valuable in testing a wide range of building types and structural details over a broad range of hypothetical events. This lecture is concerned about the dynamic loading and associated damage produced by the detonation of high explosives materials in urban environments, a situation likely to be expected in most terrorist attacks. Historically, the analysis of explosions effects either has predominantly involved simplified analytical methods or has required the use of supercomputers for detailed numerical simulations. With the rapid development of computer hardware over the last decades, it has become possible to make detailed numerical simulations of explosive events on personal computers, significantly increasing the availability of these methods. On the other hand, new developments in integrated computer hydrocodes complete the tools necessary to carry out the numerical analysis successfully. Important effects such as multiple blast wave reflections, the mach effect, rarefactions, and the negative phase of the blast wave can be readily modeled in computational fluid dynamics (CFD) codes. Simplified analytical and semiempirical techniques many times ignore such phenomena. Thus, modeling modern building sets in congested urban centers usually requires the use of sophisticated CFD numerical calculations. As an application, a new methodology to determine the mass of explosive in terrorist attacks is presented. Considering that, in spite of the tools mentioned previously, the detailed modelation of explosive, soil, urban environment and structures could be computationally prohibitive at present, a strategy based in different stages and scales is proposed. The first stage is the study of crater that is a useful tool to achieve the objective of determines the focus and the mass of the explosive. The second stage is the analysis of the damage in near constructions. This stage is performed at different scales: urban, buildings and structures.
Ricardo Daniel Ambrosini received his Ph.D. in Structural Engineering from the Structures Institute of the National University of Tucuman. He is currently a professor in the structural engineering program at the National University of Cuyo (Argentina). Dr. Ambrosini’s research interests are structural dynamics with applications to earthquake, wind and blast engineering.