NUMERICAL INVESTIGATION OF THE FIRE BEHAVIOUR OF CIRCULAR HOLLOW COLUMNS MADE OF HIGH-STRENGTH STEEL

This paper presents the results of a comprehensive numerical analysis on the behaviour of Circular Hollow Sections (CHS) columns made of High Strength Steel (HSS) at elevated temperature. In details, three full-scale HSS CHS columns with measured yield strength of about 820 MPa were tested under the standard ISO 834 fire with constant slightly eccentric compression applied load. The applied loads during the tests were respectively equal to 10%, 14% and 19% of the axial capacity of the columns at ambient temperature. Then, a fully coupled thermomechanical analysis was performed in ABAQUS. The calibration of the numerical model was carried out against experimental data by exploiting the thermal and the mechanical properties of steel provided in EN1993-1-2. A sensitivity analysis was successively performed to highlight the main parameters that affect the simulation results. The calibration process showed good agreement between the numerical results and the experimental outcomes both in terms of critical temperature and of failure mode hinting that the steel properties provided in EN1993-1-2 were capable of well reproducing the fire behaviour of the CHS columns made of HSS tested in the European project called ATTEL.