Investigation of Vulnerability of Concrete Filled Steel Column Connections under Different Blast Scenarios

Considering the increasing hostile and terroristic threats in the country, it is important to consider the passive defecncecriteria in structures. The desirable properties of steel and concrete cab be used simultaneously to increase the strength of structural members. Concrete-filled steel tube columns (CFSTs) have been proposed as an efficient system in the previous years. The main problem with using this type of column is how to connect the beam to such a column and extensive researches has been done for seismic load scenarios. Despite the excellent resistance of these types of columns to the blast load, no comprehensive investigation has yet been conducted on the performance of beam-to-column joints under blast load. In this paper, the behavior of three types of beam-to-column connections under 5 blast scenarios is investigated. ABAQUS software was used to conduct the research. Verification was first performed using the results of an experimental study and a good agreement was observed. The behavior of beam-to-column blast-loaded connections was investigated using 16 different models using explicit nonlinear dynamic analysis. The results were compared in terms of stress, strain and damage contour as well as force, energy absorption, displacement, rotation and torsion diagrams. It was observed that when the connection was carried out as an extension of the beam inside the column, all parts of the column contributed in the load carrying and energy absorption and very good behavior was observed. In this case, the plastic joint in the beam is formed away from the column face.