Elastic–plastic response spectra for exponential blast loading

The design of structures subjected to loads due to explosions is often treated by means of elastic–plastic response spectra. Such spectra that are currently available in the literature were computed on the basis of triangular shape of blast pressure with respect to time. In the present paper, response spectra based on an exponential distribution of blast pressure, which is in better agreement to experimental data, are proposed. To that effect, analytical expressions of the solutions of the pertinent equations of motion have been obtained via symbolic manipulation software, and have been used to carry out an extensive parametric study. A comparison of the spectra obtained by the proposed approach to the existing ones, reveals that the commonly used assumption of triangular blast load evolution with time can sometimes be slightly unconservative, particularly for flexible structural systems, but can also be significantly overconservative for stiffer structures.