Analysis of Blast Resistant Building

Abstract

Blast loads generated by accidental industrial explosions or intentional explosive attacks can cause severe damage to structures and pose significant risks to human life. Conventional reinforced concrete (RCC) buildings are generally designed to resist gravity, wind, and seismic loads; however, they may not possess adequate resistance against the high-intensity, short-duration forces associated with blast events. Therefore, the development of blast-resistant structural systems has become an important area of research in structural engineering. The present study investigates the behavior of a three-storey reinforced concrete building subjected to blast loading using advanced nonlinear finite element analysis. The blast pressures are generated using the CONWEP (Conventional Weapons Effects Program) approach based on TNT equivalent charge weight and stand-off distance. A detailed three-dimensional numerical model of the RCC building is developed in ABAQUS/CAE, and the dynamic response is evaluated using ABAQUS. The analysis focuses on evaluating key structural response parameters such as displacement, stress distribution, concrete damage, and overall structural performance under various blast scenarios. The influence of blast intensity and stand-off distance on the structural response is examined to identify critical conditions that may lead to excessive deformation or damage. The results demonstrate that blast effects decrease significantly with increasing stand-off distance, while higher explosive charge weights produce greater structural stresses and displacements. The study further highlights the effectiveness of nonlinear dynamic analysis in predicting damage mechanisms and assessing the blast resistance of reinforced concrete buildings. The findings of this research contribute to the understanding of blast-resistant structural design and provide practical recommendations for improving the safety and resilience of RCC buildings located in industrial, strategic, and high-risk zones.

Introduction

This study investigates the blast-resistant design of reinforced concrete (RCC) buildings subjected to accidental industrial explosions and other blast hazards. Industrial facilities handling hazardous materials pose significant risks due to explosions from process equipment, storage tanks, or flammable gas releases, which generate high-pressure, short-duration loads capable of causing severe structural damage. Unlike conventional loads such as gravity, wind, and earthquakes, blast loads require specialized dynamic analysis and structural detailing focused on energy absorption and ductility. The research aims to develop practical and code-compliant blast-resistant design methodologies for mid-rise RCC buildings using advanced numerical simulation tools.

The primary objectives are to estimate blast load parameters using TNT equivalency and CONWEP (Conventional Weapons Effects Program) formulations, develop a three-storey RCC building model in ABAQUS, perform explicit nonlinear dynamic analyses, optimize member sizing for improved blast resistance, and establish a comprehensive design methodology suitable for blast-prone industrial environments. The study addresses the gap between conventional structural design practices and the increasing need for blast-resistant construction near hazardous facilities and high-risk zones.

The literature review shows that blast loading causes complex structural responses including cracking, spalling, scabbing, excessive deflection, and progressive collapse. Previous studies have identified critical factors affecting blast performance, including explosive charge weight, standoff distance, concrete strength, reinforcement detailing, and structural configuration. While software such as ETABS, STAAD Pro, LS-DYNA, and AUTODYN has been widely applied, relatively few studies have investigated complete RCC buildings using advanced nonlinear finite element analysis with ABAQUS, Concrete Damage Plasticity (CDP), and CONWEP blast modeling. This represents the primary research gap addressed by the present study.

The proposed methodology begins by defining representative blast scenarios based on explosive charge weight, location, and standoff distance. Blast pressure-time histories are generated using the CONWEP empirical model and applied to the finite element model as external dynamic loads. Nonlinear time-history analyses are then performed to evaluate global structural behavior, including inter-storey drift and floor accelerations, as well as local damage such as hinge formation, slab punching, and material failure. The findings are subsequently used to recommend blast-resistant design improvements.

The study employs ABAQUS/Explicit, which is specifically designed for high-speed dynamic events such as explosions and impacts. The reinforced concrete structure is modeled using three-dimensional finite elements, while the nonlinear behavior of concrete is represented through the Concrete Damage Plasticity (CDP) model, enabling simulation of tensile cracking, compressive crushing, stiffness degradation, and progressive damage. Steel reinforcement is modeled using the Johnson–Cook constitutive model, which accounts for strain hardening, strain-rate sensitivity, thermal softening, and damage evolution under high-rate loading conditions.

The paper also discusses different categories of explosions, including unconfined explosions (air bursts and surface bursts), confined explosions occurring within enclosed structures where reflected pressure waves amplify loading, and contact explosions, where explosives are attached directly to structural members, producing extremely localized stresses and crushing effects.

ABAQUS serves as the primary computational platform throughout the research. It integrates finite element modeling, nonlinear material behavior, CONWEP blast loading, realistic boundary conditions, and explicit dynamic analysis to generate displacement histories, stress and strain distributions, reaction forces, damage contours, and energy absorption characteristics. Compared with full fluid–structure interaction simulations, the CONWEP approach provides an efficient balance between computational cost and engineering accuracy by eliminating the need to explicitly model the surrounding air domain.

For validation, the study models a three-storey RCC residential building with dimensions of 3.2 m × 3.2 m × 7.2 m, incorporating reinforced concrete beams, columns, and slabs designed according to Indian Standards. Material properties for both concrete and reinforcing steel are defined using CDP parameters for tensile and compressive damage and Johnson–Cook parameters for steel behavior under blast loading.

Conclusion

A detailed three-dimensional finite element model of the RCC building was successfully developed in ABAQUS/CAE and analyzed using the ABAQUS/Explicit solver. The nonlinear dynamic time-history analysis enabled accurate assessment of the transient response of the structure under blast loading. Parameters such as displacement, stress distribution, and structural damage were evaluated to understand the behavior of the building during and after the blast event. The analysis results showed that the structural response increased with increasing TNT charge weight. The maximum displacement increased from 40.3727 mm for the 20 kg TNT charge to 63.123 mm for the 40 kg TNT charge, while the maximum Von Mises stress increased from 2.50 MPa to 7.185 MPa. The increase in stress and displacement values confirmed the direct influence of blast intensity on structural behavior. However, the structure remained stable under all loading cases considered in the study. Overall, the results confirm that the selected three-storey RCC building possesses adequate blast-resistant characteristics for the loading conditions considered in this investigation. The use of ABAQUS together with the CONWEP blast loading model proved to be an efficient and reliable approach for evaluating structural performance under explosive loading. The findings of this study contribute to the understanding of blast-resistant design and provide useful guidance for the planning, analysis, and design of structures in blast high-risk zones.

References

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Copyright

Copyright © 2026 Mr. Gaurav S. Diware, Prof. Hemant B. Dahake. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.