Blast Loads in and Urban Environment

The prediction of casualties and building damage, as well as the development of structural retrofits and blast mitigation methods, for blast in an urban environment depends heavily on the ability to accurately model propagation of air blast in such an environment. The Technical Support Working Group (TSWG) of the Combating Terrorism Technology Support Office (CTTSO) of the Office of the Secretary of Defense and the United States (U.S.) Department of Homeland Security (DHS) Science and Technology Directorate (S&T) have decided to address this issue through large-scale blast tests of simulated urban environments, as well as through the application of state-of-the-art numerical modeling, to assess how accurately the complicated reflection, diffraction, and diffusion of the blast wave can be predicted. The use of large-scale test specimens within a range of typical urban scenarios will provide a very large and realistic data-base. The ongoing, multi-year test effort is being performed by the Energetic Materials Research and Test Center (EMRTC) at their Simulated Urban Environment facility. Protection Engineering Consultants (PEC) is managing and directing the numerical modeling component of this program using a team of highly capable and well qualified organizations, which develop and apply their own computational fluid dynamics (CFD) codes and fast running models (FRMs). The experimental data collected by EMRTC will serve as a key benchmark for current numerical model assessment and for future code development and modification. Special care is being taken to ensure these tests yield the highest quality data possible, given the available resources. The breadth of the collected data will be more than sufficient to assess the current state of the art in numerical modeling. Numerous tests have been conducted to date. Two urban environment scenario layouts, with multiple charge configurations, have been tested at EMRTC. PEC is developing and populating a database of experimental and numerical results, defining the data analysis procedures, and statistically assessing the database to quantify the performance of each CFD code.