Weak axis response of steel I-sections subjected to close-in detonations

The response of I-shaped, or wide-flange, sections subjected to close-in detonations has been evaluated through numerical simulations. A simulation approach for close-in detonation, which includes two stages, is suggested. The first stage includes the modelling of the detonation process through computational fluid dynamics (CFD) and the second stage includes only the free vibrations of the structural member. The suggested approach is validated by a comparison with two experimental results for close-in detonations. Then, a parametric study for I-sections with their weak axis subjected to close-in detonations has been performed. Various spherical charges and standoff distances have been studied, with scaled distances in the range of 0.15–0.29 m/kg^1/3. Bare members and members strengthened with stiffeners have been simulated. The influence of charge and standoff distance, and the addition of stiffeners on several parameters affecting deformation and folding angles, has been studied. The effect of localized pressure confined between the flanges and the stiffeners at the midspan, which can lead to increased total and local deformations, is illustrated. Finally, an alternative strengthening method, in which the flanges are connected with bars, is presented as an optional stiffening technique.