Performance of composite and tubular columns under close-in blast loading: A comparative numerical study

Abstract

In the present scenario, rapid industrialization and political conflicts across the globe result rise in malicious terrorist activities in the form of blasts and explosions targeting specific civil engineering structures. Damage caused by such blast loading may be of serious consequences in terms of huge material loss and fatalities. Therefore, investigations on construction and strengthening technique to improve the blast resistance of the critical components of the structure are of considerable interest. In the present study, an experimentally tested square RC column with seismic lateral reinforcement carrying axial load subjected to an explosive charge of 100 kg ANFO (82 kg-TNT equivalent) at a scaled distance of 1.00 m/kg1/3 with 10 mm mesh size using ABAQUS/CAE software equipped with concrete damage plasticity model is considered for validation. To have the superior performance of the RC column, efforts have been made by considering eight equivalent RC columns including composite, CFST, CFST with in-plane cross reinforcement, and CFDST to the experimentally tested one under close-in blast are analyzed. The numerical models have been developed by considering equivalent peak pressure of 8.71 MPa under the close-in blast. Parameters such as maximum transverse displacement, stresses, crack depth, and damage to the columns are studied and compared. It has been found that the CFST column with in-plane cross reinforcement and the composite column with seismic reinforcement give superior blast performance under the close-in blast loading. The two superior columns are strengthened with C-FRP wrapping over the mid-height region and analyzed under the same loading. Improved performance of the columns is discussed and compared and the column giving the best performance is identified.