Dissipative joints in robustness-related scenarios – Experimental and numerical investigations

This paper presents the findings of an experimental and numerical study on the full-range behaviour of FREEDAM (FREE from DAMage) beam-to-column joints, with particular focus on their response under column loss scenarios. Two full-scale experimental tests were carried out to evaluate the joint performance under (i) bending moment and (ii) combined bending moment and axial force. The experimental results demonstrated that the sliding resistance and overall response are strongly influenced by the initial bolt preload and by preload loss occurring during the slippage phase, leading to an average reduction of approximately 30% in friction resistance. The tests also showed that the shear failure of the damper bolts governs the ultimate capacity of the joint after damper stroke exhaustion. A simplified component-based spring model was validated against the experimental response, proving capable of reproducing the joint behaviour with satisfactory accuracy when preload loss is properly accounted for. Advanced finite element models were further validated and used to investigate local joint mechanisms and to perform parametric studies on bolt preload effects. These results confirm the suitability of FREEDAM joints for robustness-oriented design and provide validated modelling tools for their implementation in global structural analyses.