Damage modes and mechanism of steel box arch ribs under contact explosion

Abstract

Field blast experiments were conducted on two single-span steel box arch ribs, aiming to understand their damage modes and mechanisms under contact explosions. A finite element model was developed to predict the local deformation of the steel box arch ribs, which was then used for parametric studies. These studies considered factors such as explosive type, rise-span ratio (f), cross-section size, arch plate slenderness ratio (w/t₁), and the depth-to-width ratio (b/t₂) of internal stiffener. The results revealed a localized damage pattern near the detonation point, with the steel box arch ribs absorbing the majority of the energy and exhibiting no global response. Damage modes were categorized as slight, moderate, severe, and localized collapse types, with repair options ranging from welding plates and stiffeners to replacing segments of the steel box arch ribs. A formula for calculating the damage size of a steel box arch rib subjected to contact explosions was also provided. It was also observed that internal and kinetic energy were significantly affected by the explosion type, cross-section size, rise-span ratio, and arch plate slenderness ratio (w/t₁), while being less influenced by the depth-to-width ratio (b/t₂) of the internal stiffener. The steel box arch rib exhibited significantly lower effective stress and maximum principal stress compared to the steel beam, owing to the arch effect. The present research work underscores the importance of understanding how various factors interact to mitigate explosion-induced damage to steel box arch ribs.