Simplified Numerical Model Reproducing the Nonlinear Behavior of a Knee Bracing System Equipped with a Dissipative Fuse

Seismic-resistant structures can dissipate energy during earthquakes through the yielding of localized and pre-designed members, while other elements of the structure remain in elastic field. In this work, the structural behavior of a dissipative knee bracing system that relies on the yielding of a fuse, is numerically investigated by means of a developed simplified numerical model capable of reproducing the fuse response. The model is calibrated on experimental tests performed on different typologies of the fuse and its accuracy is confirmed by the comparison with experimental results in terms of dissipated energy and failure mode. The model is able to reproduce the effect of the bending moment, shear and axial force simultaneously acting on the fuse and it can be adopted to assess the structural response of earthquake resistant steel structures where the dissipation of energy relies on knee bracing systems equipped with this dissipative device.