NEAR-FIELD BLAST-RESISTANT TEST OF REACTIVE POWDER CONCRETE FILLED STEEL TUBULAR COLUMN AFTER EXPOSURE TO STANDARD FIRE

Near-field blast-resistant tests of four large-scale Reactive Powder Concrete Filled Steel Tubular (RPC-FST) Columns after exposure to standard fire were performed at a test site. The influences of scale standoff distance and fire duration on dynamic responses and failure modes of RPC-FST column specimens under constant axial forces were discussed. It was indicated that the RPC core columns could be effectively confined by outer steel tubes when exposure to standard fire and the high temperature bursts of RPC were restricted. A good fire-resistant capacity of RPC-FST was experimentally verified. The relative displacements of RPC-FST column after exposure to standard fire under blast loading were all exceed 2.0%. This means that they were satisfied the yielding state. The deformations of a RPC-FST column were transferred from bending types to bending-shear types with scale standoff distances decreased from 0.58 m/kg^1/3 to 0.48 m/kg^1/3. Obvious plastic deformations could be observed at the mid-span section of a RPC-FST column as fire duration large enough, the maximum displacement and residual displacement were increased greatly, resulting in a typical bending failure. The blast-resistant capacities of RPC-FST columns were more sensitive to fire durations than scale standoff distances. Experimental data were simulated by using LS-DYNA codes, and the numerical results were in a good agreement with the experimental data.