BREAS - Blast Response Assessment of Structures

The German Federal Armed Forces (Bundeswehr) are currently involved in several globally important deployments abroad. This requires the accommodation of personnel and the necessary infrastructure at the site of deployment. The storage of ammunition onsite constitutes a hazard within the accommodation infrastructure that is to be assessed. The provisioning of ammunition has the same hazard potential in basic operations of the Bundeswehr. In case of ammunition detonation, individuals or objects are considerably at risk.

With its expertise and the development of software solutions, Fraunhofer EMI is part of a board for the assessment of ammunition storage safety. Besides EMI as scientific partner, Bundeswehr departments dealing with this topic are actively participating in this board, e.g. the Technical Center for Protective and Special Technologies (WTD 52), the Federal Office for Infrastructure, Environmental Protection and Public Service, the Bundeswehr Territorial Tasks Command and the Bundeswehr Logistics Command. Thanks to the successful long-term collaboration, the results of EMI’s studies and the resulting tools have meanwhile been integrated in the Bundeswehr guideline for risk management in ammunition storage.

In dependence of troop strength and current regulations, the demands and proper storage can be assessed with the EMI software ASASP (Ammunition Storage and Site Planning Tool). By comparing the simulations with the real spatial situation, it can be examined whether safety distances are complied with.

When the safety distances are deceeded, the EMI tool ESQRA-GE (Explosives Safety Quantitative Risk Assessment Germany) allows the assessment of potential risks, thus offering decision support. Hazards resulting from fragments, debris and shock waves as well as their effects on persons, vehicles and buildings are assessed. Specifically, the expected building damage is merely examined with phenomenological models.

Thus, we were looking for a way to compute the component behavior under blast loading in a pragmatic yet precise manner. The software tool BREAS (Blast Response Assessment of Structures), which completes the Bundeswehr software tool portfolio in terms of ammunition safety, is the result of this research project. BREAS is an expert software developed at EMI that serves the detailed damage assessment of building structures under blast loading.

The BREAS expert software

BREAS is an EMI-developed expert software for damage assessment of building structures during detonation events. In contrast to the majority of finite element methods, BREAS allows a fast and simple assessment of the behavior of structural components under highly dynamic loading. Arbitrary building configurations can be considered and visualized on a graphical interface. The absolute loading capacity is analyzed, and a damage assessment of the infrastructure is carried out using a color scale. The basis of assessment is an engineering model at plane loading assumption, where the critical structure deflection during blast loading is computed and visualized.

Single buildings or building clusters can be analyzed in detail. The user is guided through the configuration and positioning by a three dimensional graphical interface. For an efficient damage analysis, buildings as well as containers are broken down into their elements and assessed individually. For the container types, these attributes are set by default, whereas the buildings can be configured freely. Thus, even longer façade sides can be examined.  

In addition to typical elements found at deployment sites, such as containers and buildings, safety measures by crossbeams and barriers with bulk material or structural reinforcements are also taken into account. Setup and type of the crossbeams and barriers are based on common variables as listed in the guideline for safe storage of ammunition. The calculation of factors that mitigate the detonation effects forms the basis for taking into account the protective effects of crossbeams or barriers with bulk material. Furthermore, the correlation with cost factors facilitates the assessment of the efficiency of various protective measures.

Two different methods are employed to assess the hazard potential: with semi-empirical assumptions, the loading of structural components or buildings can be calculated via the quantity of hazardous substance and the distance.

Via a finite volume scheme, an interface to the APOLLO BlastSimulator software allows the consideration of focusing and shading effects that occur during complex blast wave propagation scenarios in densely built urban environments.

Besides the evaluation of potential damage of ammunition storage, the BREAS software can be used in explosive ordnance clearance in order to assess potential hazards and to offer decision support for explosive ordnance disposal teams.