Air-blast and ground shockwave parameters, shallow underground blasting, on the ground and buried shallow underground blast-resistant shelters: A review

Abstract

Weak political systems and poor governance in certain developing countries are found to have a war-like environment where structures are being targeted by blasts and bombs. Industrial blasts due to frail know-how and mishandlings are also quite common. Recent accidental explosions like that occurred at the Beirut Port, Lebanon (August 2020); ammunition depot in the outskirt of the Ryazan City of Russia (November 2020) are of concern for the safety of adjacent building infrastructure and their users. Such intense loading events cause damage to certain elements of a structure which may result in disproportionate or progressive collapse. It necessitates a clear understanding of the phenomenon of the blast and extreme loads induced out of it, and response of the target structure under such loadings. In this study, the state of research on air-blast and ground shockwave parameters, shallow underground blasting, and on the ground and buried shallow blast-resistant shelters are presented. The phenomenon of the self-Mach-reflection of the explosion, loading parameters and empirical blast models available in the open literature followed by the damage criteria for the buildings subjected to the underground blasting and available peak particle velocity (PPV) prediction models have been discussed. To make the application of advanced materials such as fibrous concrete, ultra-high performance concrete, FRP composites, etc., it is important to comprehend the existing blast/shock-resistant shelters and their response under such loading. The shelters are primarily designed by incorporating features of the materials like high degree of deformability/ductility, use of the shock-isolation panels and the mechanism for controlling crack formations. Finally, conclusions and recommendations for future studies are summarised. This paper presents prospects to engineers, town planners, researchers, policymakers and members of the core drafting sectional committees to understand the phenomenon of the blast and extreme loads induced out of it.

Evaluation of critical damage location of contact blast on conventionally reinforced one-way square concrete slab applying CEL-FEM blast modeling technique

“…Explosions, whether accidental or man-made, can cause severe damage to the building infrastructure resulting in fatalities to occupants of the buildings in close proximity to the center of the explosion (Anas et al, 2021b, 2021d; Anas and Alam, 2021b; Kyei and Braimah, 2017). Explosive-induced incidents are occurring more frequently (Anas et al, 2021b), therefore, blast performance of building infrastructures conventionally designed for strength and economy is of serious concern to the engineers (Anas et al, 2021b; Kyei and Braimah, 2017).…”

“…Explosive-induced incidents are occurring more frequently (Anas et al, 2021b), therefore, blast performance of building infrastructures conventionally designed for strength and economy is of serious concern to the engineers (Anas et al, 2021b; Kyei and Braimah, 2017). Past devastating man-made explosion incidents such as those that occurred in Oklahoma and New York City and many more across the globe expose the degree of vulnerability of buildings not designed to withstand such extreme blast-induced loadings (Anas et al, 2021d; Myers et al, 2004). It is worth mentioning that how much blast resistance the building or its vulnerable key elements should be provided to control the damage from some acceptable pressure produced by explosions (Anas et al, 2021b).…”

“…Explosives that may be considered in the structural design include improvised explosive devices (IEDs), military weapons (aerial bombs), and non-nuclear chemical explosives (TNT/TATP/PETN/RDX/Semtex/Aziroazide azide), which are being highly endorsed and deployed to trigger blasts across the globe (Anas et al, 2021d; IS 4991, 1968; Kingery and Bulmash, 1984; TM 5-1300, 1990; UFC 3-340-02, 2008). The misuse of these explosives to incur blasts in the buildings is extremely catastrophic leading to huge damages to the building infrastructure as well as to the lives and assets of the people present there, causing them to encounter grave injuries, which can sometimes turn out to be fatal as well (Anas et al, 2021b).…”

“…The explosives and the blasts caused using them are classified in a few categories as per the weight of the explosive used. The categories are small (W TNT ≤ 5.0), medium (5.0 < W TNT ≤ 20.0), large (20.0 < W TNT ≤ 100.0), and very large (W TNT > > 100.0), where W TNT is the weight of explosive in “kg-TNT” (Anas et al, 2021b, 2021d). The structural response/damage caused by blast-induced impulsive load takes place for a quite shorter period of time, generally micro- to milli-seconds, and has a very high magnitude as compared to other quasi-static and lower intensity dynamic loads, that can be instigated by pressures of wind, wave, or earthquake (Anas et al, 2021f).…”

“…Additionally, the responses received from a structure and its materials under such extreme loadings do not certainly lead to the reliable prediction of the structural response/damage. Rather, they are overtly non-linear with complex stress states and are time-dependent delivering available design practices in the current design standards/manuals (Anas and Alam, 2021a, 2021b, 2022a; Anas et al, 2020a, 2020b, 2020c, 2021a, 2021b, 2021c, 2021d, 2021e, 2021f; DOE/TIC-11268, 1992; TM 5-1300, 1990; UFC 3-340-02, 2008). Under blast engineering, which is considered to be a specialized field of structural engineering, the majority of the structural engineers have little to no awareness of the concept of blasts, loadings induced out of it, and dynamic response of the protective or target structures under such extreme short-duration/high-magnitude loading (Anas et al, 2021b).…”