Near-field blast test on reactive powder concrete-filled steel tubular columns after exposure to fire

Abstract

The existing blast tests of concrete-filled steel tubular are mainly on the dynamic behaviors of concrete-filled steel tubular at ambient temperature. ANSYS codes are used to simulate the temperature distribution of reactive powder concrete-filled steel tubular, and subsequently an approximate approach is used to estimate the residual strength of reactive powder concrete. Then blast-resistant capacities of four large-scale reactive powder concrete-filled steel tubular columns after exposure to ISO-834 standard fire are experimentally examined. The overpressures of shock wave, displacements, and strains of reactive powder concrete-filled steel tubular columns are recorded by advanced gauges. Influences of fire durations and scaled stand-off distances of explosive charge on dynamic behaviors and failure modes of reactive powder concrete-filled steel tubular columns are discussed. It is shown that reactive powder concrete-filled steel tubular columns retain excellent blast-resistant capacity after exposure to fire. Reactive powder concrete core column can be effectively confined by steel tube, but its blast-resistant capacity decreases as explosive charge or fire duration increases. Failure modes change from bending types to bending-shear types as explosive charge increases, and obvious plastic deformation at the mid-span section can be observed in the reactive powder concrete-filled steel tubular columns with fire duration of 105 min. It is also indicated that the maximum displacement of reactive powder concrete-filled steel tubular columns is more sensitive to fire duration than to explosive charge weight.