Single-degree-of-freedom approach to incorporate axial load effects on pressure impulse curves for steel columns

© 2014 American Society of Civil Engineers. In this paper, the moment-curvature behavior of a steel column under constant axial loading is implemented into a computationally efficient one-dimensional finite-element approach, utilizing Timoshenko beam theory, to determine the dynamic response of steel columns subjected to blasts. Then, a new single-degree-of-freedom (SDOF) approach is provided for determining pressure impulse curves for steel columns under constant axial loading. This SDOF approach relies on the newly defined concept of the reduced resistance-deflection function to accurately simulate the PΔ effects and the global instability failure mechanism, which are both caused by the axial load. The aforementioned finite-element approach is then used to thoroughly validate the newly proposed SDOF approach for deriving pressure impulse curves. It is shown that, despite the inherent simplicity of the approach, the newly proposed SDOF approach provides accurate and reliable results