Dynamic Response Analysis of Slab Subjected to Central Contact Blast: Exploring Effects of Blast Placement on Compression and Tension Faces

Abstract

The fortification of military and civilian infrastructures against explosive events has garnered heightened consideration among structural engineers, owing to the surge in subversive detonations and inadvertent blasts witnessed in recent times. Notable examples include the Beirut port explosion in 2020 and the Kabul airport attack in 2021, which underscore the critical need for enhanced protective measures in structural design. In the domain of structural engineering, safeguarding slender structural elements, notably slabs, emerges as a pivotal concern. Slabs, integral constituents within architectural constructs, bear significant responsibility in upholding structural integrity and providing support. Nonetheless, their slender configuration exposes them to heightened vulnerability in the face of detonations, particularly those initiated by direct contact. In contrast to sturdier structural components like columns or walls, slabs exhibit diminished mass and intrinsic resilience, rendering them predisposed to deformation, fracturing, and ultimate failure when subjected to explosive forces. This research employs an Integrated Eulerian Lagrangian formulation within the framework of the FEM, utilizing the dynamic computational tool Abaqus/Explicit. Its objective is to scrutinize the behavior and efficacy of a mono-reinforced one-way concrete slab when subjected to a central contact explosion. The computational model undergoes validation through comparison with experimental findings readily available in the public domain. Subsequently, the validated model is applied to explore the response of the slab in two distinct scenarios: in the initial configuration, the TNT charge is positioned on the upper surface, designated as the compression face, while in an alternate configuration, it is situated on the lower surface, known as the tension face. The damages incurred by the slab for the two distinct blast scenarios are compared to gain better insight into the structural response under differing blast conditions. Results showed that the placement of TNT explosives at the lower surface (tension face) of the slab (Scenario: II) led to increased upward deformation and tensile stress in reinforcement bars compared to Scenario I. Specifically, Scenario II exhibited a 1.27-fold increase in deformation and heightened stress intensity, indicating greater severity in terms of damage and structural failure potential.