Experimental Analysis of Beam-to-Column Joints and Column Bases Made of High Strength Steel Tubular Columns Subjected to Earthquake Loading

Although High Strength Steel (HSS) has been primarily employed in mechanical applications, its use is becoming more common in the construction industry too, owing to its excellent structural properties. Circular columns are suitable in structures subjected to loading in multiple directions, like welded steel frames, because of uniform geometrical characteristics along all cross-sectional directions. Therefore, HSS can be conveniently employed in tubular columns of moment resisting frames located in moderate seismic-prone regions. In this respect, the Research Fund for Coal and Steel (RFCS) project called ATTEL was funded to promote the use of HSSS590 members with circular sections in buildings by investigating both seismic and fire behaviour with the aim to show possible benefits with respect to mild steel S355. The present work focuses on the study of innovative solutions both for beam-to-column joints and of column-base joints designed in order to withstand the seismic action. The joints are part of a moment resisting frame designed according to the capacity design and made ofmild steel beams and of HSS columns filled with concrete. Tests on full-scale joints were performed to investigate the actual hysteretic behaviour and the seismic response of the joints and experimental data were used to calibrate numerical models.