Experimental study on the dynamic response of steel structure subjected to blast load

Studying the dynamic response of a structure subjected to a blast loading has always been of interest, especially for the army, navy and any defense infrastructure facilities. In the blast resistant design of a structure, failing to incorporate an appropriate material model or neglecting FSI effects can lead to an erroneous prediction of structural responses. Experimental studies in this area have primarily focused on impulse loading and the associated structural responses with minimal work spanning a broad spectrum of the $t_d/t_n$ ratios ($t_d$ is the duration of the blast load, and $t_n$ is the natural period of the structure). International codes and the Single Degree of Freedom (SDOF) procedure on blast resistant design of structures do not account for the FSI effects, thereby resulting in a considerably conservative design. To address the above gaps, shock tube experiments using Blast Wave Simulators (BWS) are conducted across a wide range of $t_d/t_n$ ratios (0.2 to 17), by varying the parameters such as (a) sample thickness, (b) support/boundary conditions and (c) blast load intensity. Experimental observations reveal that less-stiff structures undergo significant deformation, which reduces the load acting on the structure compared to more-stiff structures. Comparing the experimental results with the analytical approach shows that the peak-reflected overpressure is overpredicted in the analytical approach with a maximum difference of 30 %. It is also found that there is a significant difference between the experimental results and the analytical model (or) the existing standard procedure on the blast resistant design of the structure. Overall, this study highlights the importance of incorporating FSI effects and an analytical approach with realistic material modeling in the blast resistant design of structures.