The prevalence of worldwide terrorist activity has created a large demand for engineers capable of performing blast effects analyses for threat assessments, designing to mitigate threats to new and existing buildings and systems, and blast effects testing. To meet this demand, many companies tout their blast engineering capabilities and claim to possess expertise in what has, until recently, been a very specialized and highly technical field.
Indeed, much information is available from published manuals which can be obtained and utilized by engineers. Yet, many realistic blast-effects situations violate the simplifying assumptions of design manual methods-often in ways that may lead to a violation of the constraints governing their application. Understanding and applying published blast effects design information is not comparable to following the building code for conventional construction. Actual bomb scenarios often require more sophisticated analytical methods than are readily available in the literature or in the simplified software tools provided by the Government.
When selecting an engineering consultant to perform blast effects analysis or provide blast-resistant designs, it is important that Government agencies, institutions, corporations, and A&E firms ask the following questions to distinguish the novices and those with a narrow set of skills from those who can provide proven and broad-base expertise that is based upon engineering skills gleaned from years as a practicing blast effects expert.
Does the consultant have an extensive and broad-base history of blast effects engineering studies and designs?
Blast effects engineering involves numerous subtleties that are often not appreciated by a novice and that are best acquired over the course of many projects in diverse sub-areas: explosive safety, terrorist-resistant retrofit and new design, blast effects testing, and weapon effects analysis. Experience is needed for the proper use of engineering models that predict blast effects and their consequences, particularly as these models are typically poorly documented and in a perpetual state of flux. Experience is also essential for addressing all aspects of a problem (e.g., shear, bending, and membrane response of a flexural member), or the varied ways in which the size and shape of a building affects the reflected pressure and impulse loads. Such experience cannot be acquired in a one-week course or simply by reading a reference.Does the consultant have access to a broad range of analytical methods?
Often, simple look-up curves are inadequate for a particular situation and must be augmented by more complex models. The consultant should have access to and expertise in the utilization of a wide range of engineering models to perform such tasks as blast load computation, structural response assessment, and damage and casualty estimation. Should the situation warrant, first-principles codes (e.g., nonlinear finite element codes for structural response or hydrocodes for blast propagation) can be used to analyze more complex geometries or to reduce the level of conservatism inherent in the engineering models. The blast consultant must be experienced in all types of models and understand the appropriate scenario in which each is to be utilized.
top