PSI - Issue 82

Addisu Bonger et al. / Procedia Structural Integrity 82 (2026) 30–36 Addisu et al. / Structural Integrity Procedia 00 (2026) 000–000

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these boundaries may have further intensified the concrete fracture. Similar fracture patterns were observed experimentally (Fig. 4a, pink lines), Wada et al. (2021). Fig. 4c presents the initiation of pressurized gas, its expansion, and subsequent release through fracture pathways. The simulation results reveal a coupled interaction between gas pressure-induced crack propagation and the resulting pressure decline as gas escapes through the formed cracks. Pressure release predominantly occurs along the lateral surfaces of the specimen, attributed to extensive concrete damage in these regions compared to the relatively intact upper surface. The deformation of the stud dowels and reinforcement is shown in Fig. 4d. The stud dowel located at the specimen's edge experienced a maximum deformation of about 5.2 mm in the x-direction as shown in Fig. 3d. After the release of the pressurized gas, this deformation reduced to 3 mm. Additionally, the top rebar at the center of the specimen exhibited a deformation of approximately 6.7 mm in the z-direction, as seen in the graph in Fig. 3d. These deformations in the stud dowels and rebars contribute to concrete crushing and the spread of cracks. To determine whether the steel girder and stud dowels could be reused, strain was analyzed at points of maximum deformation identified in the simulation. As illustrated in Fig. 4e, the residual strain levels stayed below the yield limit, indicating that yielding did not take place. Experimental findings by Wada et al. (2021) further validated this observation, reinforcing the feasibility of reuse. 4. Conclusions The results of this study demonstrate that the numerical simulation successfully reproduces the kinetics of the experiments, confirming its effectiveness in modeling the dynamic fracture behavior of concrete. Computational analyses reveal that reduced dowel spacing causes high pore pressure rise due to a strong confinement against crack propagation. The accumulation of gas pressure in the vicinity of reinforcing bars and stud dowels induced their deformation and caused displacement of the surrounding concrete, thereby promoting local concrete crushing and further crack extension. The numerical analysis shows that a coupled interaction between gas pressure-induced crack propagation and the resulting pressure decline as gas escapes through the formed cracks. The configuration of the stud dowels and the number of cartridges influence the concrete fracture process in practice. Furthermore, both the stud dowels and the steel girder remained undeformed post-explosion, indicating their suitability for reuse in future Biot, M.A., 1941. General Theory of Three-Dimensional Consolidation. Journal of Applied Physics. 12, 155–164. Biot, M.A., 1963. Theory of Stability and Consolidation of a Porous Medium Under Initial Stress. Journal of Mathematics and Mechanics 12, 521– 541. Maekawa, K., Ishida, T., Kishi, T., 2008. Multi-scale Modeling of Structural Concrete. Oxford: Taylor & Francis. Maekawa, K., Pimanmas, A., Okamura, H., 2003. Nonlinear Mechanics of Reinforced Concrete. Oxford: Taylor & Francis. Sasaki, K., Sakamoto, R., Tanaka, M., Hidani, K., Iizuka, S., 2011. Development of an Electric Discharge Impulse Crushing System, 6 th EFEE World Conference on Explosives and Blasting, vol. 6, Lisbon, Portugal, pp. 379–400. Tanaka, S., Bataev, I., Inao, D., Hokamoto, K., 2020. Initiation of Nitromethane Deflagration Promoted by the Oxidation Reaction of Vaporized Metal Wire, Applications in Energy and Combustion Science, vol. 1-4. Uenishi, K., Wada, K., Yamachi, H., Nakamori, J., 2023. Precisely Controlled Dynamic Disintegration of Steel-Concrete Composite Structures, 5 th International Conference on Structural Integrity and Durability, Procedia Structural Integrity 46, 136–142. Wada, K., Uenishi, K., Yamachi, H., Nakamori, J., 2021. On Wave-Controlled Dynamic Disintegration of Steel-Concrete Composite Structures, Proceedings of the 15 th National Symposium on Rock Mechanics, vol. 89, pp. 505–508. Yamanoi, Y., Maekawa, K., 2022. Disintegration of Low and Normal Strength Concrete in Shear Localized Bands and Its Constitutive Modeling. Engineering Structures, vol. 266. Zažirej, S., Maekawa, K., Hosoda, A., 2024. Poromechanical Approach to Blast-Induced Dynamic Fracture in Concrete. Structural Concrete, 1–21. renovation. References