BLAST LOAD ANALYSIS OF A CONCRETE COLUMN EMBEDDED WITH PRETWISTED BARS

This study investigates the behaviour of a concrete column embedded with pretwisted bars subjected to blast loading. Pretwisted bars are those that are twisted along its central axis. It has been found out that the buckling capacity of the steel bars increases as the angle of twist increases. As a preliminary step, we find the optimum angle of twist for the steel bar by the buckling analysis of the bar over a set of twist angles. The steel bar twisted at this optimum angle is embedded in the concrete column. The column is of size 250 mm ANSYS Workbench 16.0. Later on, it was subjected to Blast Loading. The Blast analysis of the concrete column was done in ANSYS AUTODYN. The explosive was placed at a stand-off distance of 1500 mm. The blast analysis was carried out for 5000 kg, 3000 kg, 300 kg and 10 kg of TNT air box around the column to act as a medium for the blast. In order to reduce the large time consumption of the blast analysis, a one dimensional wedge which is filled with AIR and TNT materials was created in AUTODYN and it was remapped into the 3 D Air box. The blast analysis of the column is continued till the column failure or the kinetic energy absorbed in the column diminishes. The results from blast analysis shows that the column failed when subjected to can withstand with minute damages when subjected to 300 kg and 10 kg. The current study includes only blast analysis of columns that are unloaded