15.10: Probabilistic analysis of steel columns under blast induced loads

Abstract

ABSTRACTA growing interest for the design of structures to sustain blast induced loads has been observed in recent years due to the worldwide rise of terrorist bombing attacks. The blast parameters that are essential for design can be located in various publically available blast design manuals, where the proposed graphs and equations are based on a large experimental database established several decades ago. The degree of uncertainty in the determination of these parameters is significant, as a result of the unstable nature of explosives, the efficiency of the measuring equipment and the large pressure and impulse values involved in the blast phenomena.These uncertainties have been identified in the current study which focuses on the response of steel open sections under blast induced loads and addresses the influence of such uncertainties on the flexural response of axially loaded structural members. The variation of structural and load parameters was considered in the design procedure by utilizing a reliability‐based assessment methodology. A probabilistic approach was followed and the reliability of the column was defined with respect to limit states proposed in various blast design manuals. Probability curves are constructed, by using single‐degree‐of‐freedom models, showing the cumulative probability distribution of reaching a certain capacity with respect to a selected limit state. This way instead of a deterministic safe‐unsafe criterion in design, the probability of damage is introduced in relation to the applied axial load, which provides a valuable insight to the behaviour of structural members subjected to an explosion.