Cyclic behavior of composite truss beam-to-RC column joints in MRFS

In the present paper, the cyclic behavior of beam-to-column joints made up of Hybrid Steel Trussed Concrete Beams (HSTCBs) connected to Reinforced Concrete (RC) piers is investigated. HSTCBs are a typology of composite beam generally constituted by a steel truss with end zone added rebars embedded within a block of concrete cast in place. HSTCBs represent a structural solution for light industrialization in the civil constructions; the main advantages in their use are the higher construction speed with the minimum site labor, the possibility of covering wide spans with low depths and a final economical convenience. For these reasons, they are also increasingly adopted within seismic framed structures. In the present study, the examined joints are representative of framed RC structures subjected to seismic actions and designed according to the current Italian standard code. Cyclic tests are performed and interpreted by means of analytical and numerical models with the aim of verifying the strength capacity and ductility of the system, focusing on both the global behavior and the force transmission between steel truss and concrete in the joint region.