This paper describes the blast loading trials on steel tubular members with and without concrete infill. The standoff distances considered in this trial were selected to demonstrate the response of these steel sections to contact and very close-range detonations of high explosive (HE). The main objective of the trials was to investigate the effects of contact and near-field explosions on steel square tubular members and to demonstrate the effect of standoff variations on the mode of response and failure of steel square sections. The experimental data collected during these trials can be used for verification of theoretical and numerical models of response of steel tubular columns subjected to contact and close-range blasts. Due to difficulties with collecting quantitative data (displacements, blast pressures, etc.) in the close proximity of a detonating HE charge, analysis of the steel tubes in this paper is confined mostly to qualitative assessment based on visual observations of the structural damage and limited numerical simulations of the blast-structure interaction using LS-DYNA aimed at clarifying some important phenomena that were not available to be obtained directly from the explosive tests. A new simplified approach to predicting the dynamic response of square tubular steel members subjected to the near-field airblast loading is proposed. The comparison of the analytically predicted dynamic response parameters of the concrete-filled steel tubular members with the experimental data shows very good agreement with the predicted failure mechanism and level of damage of the structural element.