Dynamic Responses of RPC-Filled Steel Tubular Columns Post Fire Under Blast Loading
Blast-resistant capacities of 4 large scale circular Reactive Powder Concrete Filled Steel Tubular (RPC-FST) columns after exposure to fire are experimentally examined. The overpressures of shock wave, the deflections and strains of RPC-FST column specimens are recorded by advanced gauges. The influences of fire durations and scaled standoff distances of explosive charge on the dynamic behaviors and failure modes are discussed. It is shown that the RPC-FST columns remain excellent blast-resistant capacities after exposure to fire. RPC core column can be effectively confined by steel tube, but the blast-resistant capacities of RPC-FST columns are decreased as explosive charge or fire duration increased. The failure modes are transited from bending types to bendingshear types as explosive charge increased, and an obvious plastic hinge at mid-span section can be observed in the RPC-FST column with fire duration of 105min. It is also indicated that the maximum displacements of RPC-FST columns are more sensitive to fire duration than to explosive charge weight.
Response of Foam- and Concrete-Filled Square Steel Tubes under Low-Velocity Impact Loading
This paper presents the results of experimental and numerical studies of the comparative behavior of square hollow section (SHS) tubes filled with rigid polyurethane foam (RPF) and concrete undergoing transverse impact loading. A series of instrumented drop hammer tests were performed on mild steel and stainless steel SHSs for both filled and unfilled constructions. The concrete-filled tubes had the highest impact resistance and energy absorption capacity, followed by the steel tubes filled with RPF, and then the hollow tubes. The results also show that RPFs can be used as an effective infill material in structural steel hollow columns when expedient enhancement of the energy absorption capacity is required, e.g., to increase blast and impact resistance of hollow structural elements. Nonlinear dynamic finite-element analyses were carried out to simulate drop hammer test conditions. The predicted impact forces, deformation histories, and failure modes were found to be in good agreement with the experimenta...
A Theoretical Study of the Lateral Impact of Fully Clamped Pipelines
A theoretical rigid-plastic procedure is developed in order to predict the quasi-static response of a ductile pipeline which is fully clamped across a span and struck laterally by a rigid mass. This theoretical study allows the local or denting deformations to continue during the global deformation phase which has been considered only semi-empirically in previous work. In addition, it is valid for a mass striking at any position on the span, except very close to a support. Good agreement is obtained with the maximum permanent transverse displacements recorded in the experimental tests which are reported in a companion paper (the preceding paper in this issue) on steel pipelines having 11 ≤ D/H ≤ 62.3 and 2L/D ≅ 10 and struck at the mid span and one-quarter span positions.