Blast wave propagation in city streets—an overview

摘要

This paper presents an overview of research conducted by the authors and others both experimentally and analytically in the area of blast wave interactions with buildings and structures in an urban landscape. Empirical tools for the assessment of blast wave resultants for simple-geometry situations are first presented before the confining effects of buildings along a street are discussed. Street layouts such a T-junctions and crossroads are then introduced and the way that blast wave characteristics are affected by street width and the height of buildings along the street is assessed. The influence of the location of the explosive charge within the street layout on the blast load experienced by buildings is also reviewed. It is likely that building facades closest to the explosion will fail and the effect on the loading experienced further from the detonation is therefore assessed. A complementary study of the loads developed inside a building whose facade has failed is also discussed. Apart from the blast loads on buildings in a street in which there is an explosion, buildings in adjacent streets will also experience blast loading. Studies concerned with the phenomena of 'channelling' and 'shielding' are presented and the extent to which both processes occur in any given situation discussed. The various studies reported throughout the paper indicate that simple tools are often inappropriate and the development of empirical rules for more complex geometries may not be reliable. This view is supported by studying blast wave propagation in a realistic cityscape comprising streets of different widths with several layout features all bounded by buildings of different size, shape and height. Such studies conclude that computational fluid dynamics analyses may sometimes be the only satisfactory approach for the engineer seeking a reliable assessment of blast loads experienced by buildings in an urban landscape.