Robustness of Full Scale CFDST Columns in filled with UHPC Under Blast Loading

Abstract

When the concrete structure exposed to attack of terrorist blasts, the exterior columns are most susceptible to damage. Concrete-filled double-skin tubes (CFDST) columns and ultra-high performance concrete (UHPC) columns, both have been increasingly popular in the field of engineering in recent years. A number of recent research works proved the superior performance of CFDST and UHPC columns under different loading conditions. The current paper, combines the advantages of both concerning blast-resistance. However, very limited knowledge is known about the robustness and residual axial capacity of ultra-high performance concrete filled double-skin tubular (UHPCFDST) columns after blast loading. The available international codes lack substantial design considerations to prevent or minimize the impact caused by realistic explosion events. So before the design, it is required to understand the blast behavior of UHPCFDST columns. However, there is a paucity of literature on the response of CFDST members when used as structural columns subjected to a combination of lateral impact of blasting and axial load induced by the live and dead loads of building slabs or bridge decks. Till now, there are no full scale UHPCFDST columns exposed to blasting tests are found experimentally and nearly impossible because of security restrictions and costly in terms of both preparation and measurements. To address this gap and understanding the real blast behavior of full scale UHPCFDST columns, a nonlinear dynamic finite element (FE) models were used. Accurate nonlinear dynamic finite element models were initially calibrated with the experimental ones to ensure the actual and reliable perform of the dynamic responses and residual capacity of UHPCFDST columns subjected to different detonation scenarios. Then, a wide range of influencing factors were considered in the parametric study as charge weight, thickness of tubes and concrete compressive strength. The results obtained in terms of displacements and propagation of damage show that the above parameters influence considerably the nonlinear dynamic behavior of full UHPCFDST columns under blasting.