Effect of transverse circular and helical reinforcements on the performance of circular RC column under high explosive loading

Abstract

Columns are primary load-carrying members of the framed structure which transfer external lateral loads and gravity load of the structure to the foundation. Columns under extreme loadings such as blast may become a local hazard, failure of which can lead to the disproportionate or progressive collapse of the building. Not only the subversive reasons but accidental explosions may also cause the failure of the column(s) or building, resulting in a huge loss of economy and human lives. Blast resistance of the columns in the building is of serious concern under explosive loadings. Following the validation of 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, equivalent circular columns to the experimentally tested one having seismic circular transverse reinforcement, and column with helical transverse reinforcement carrying the same axial load under the blast are considered. Additional transverse reinforcement of CFRP is also considered over confining regions. Additional wrappings of CFRP and mild steel sheets are also used to study their effect on the blast performance of the columns. Blast performance in terms of maximum displacement, stresses, and damage to the columns are compared and discussed. The present research provides insight into the blast performance of the circular RC columns and provisions to reduce the explosive-induced failure risk.