Robustness analysis of steel frames subjected to vehicle collisions

Among the accidental loading scenarios, the vehicle collision in the ground column of a building is surely one of the most common. When a building is subjected to such an action, the beam-to-column connections are responsible for the transfer of the actions through an alternative path, thus, playing an important role in the robustness of the building. This paper presents the results of a numerical study carried out on a steel frame subjected to a vehicle collision. Two different parameters are studied: i) the influence of the type of analysis, using alternative load path approaches (column loss scenario) or by explicitly considering the action deriving from the vehicle collision in a dynamic framework and ii) the influence of the beam-to-column connection typology, considering a connection with a reduced beam cross section and an innovative type of a slide-hinge joint. The type of analysis highlighted that the use of alternative-load path method can lead to a different structural response than that coming from the impact analyses, especially if high collision velocities are considered. Concerning the adoption of different connection typologies, the results showed that the main difference of using the slide-hinge joint rather than the connection with the reduced beam cross-section is in the delay of the yielding of beam and columns due to the slip mechanism of these connections.