Dissipative connections of rc frames with prefabricated steel-trussed-concrete beams

In the last thirty years, Hybrid Steel-Trussed Concrete Beams (HSTCBs) have been widely used in civil and industrial constructions and, therefore, their mechanical performance must be evaluated with the aim of guaranteeing adequate dissipation of the seismic energy particularly in the beam-to-column joints. However, one of the most frequent peculiarities of HSTCBs is that of using their own steel joist to cover large spans with reduced depth and, in the case of traditional beam-to-column connections, this requires large amount of steel reinforcement inside the panel zone, often made with large diameter rebars. These characteristics make both the panel zone and the beam end potentially vulnerable to the effects of the cyclic actions induced by the earthquake and dramatically reduce the dissipative capacity of the entire structure. For this purpose, this study investigates the possibility of introducing friction damper devices in the HSTCB-to-column joint of framed structures in seismic areas. The use of friction dampers prevents damage to the structural elements, improves the expected performance and limits damage to the panel zone. The feasibility study is conducted through the development of design criteria for the dimensioning of the device and numerical validation of the proposed solution.