Failure Assessment of Beam-to-Column Steel Joints Via Low-Cycle Fatigue Approaches

Publisher Summary Beam-to-column joints remarkably influence the overall response of the frame and, as a consequence, the possibility to take into account accurately their behavior is of great importance for structural design. This chapter presents some approaches to monitor the damage and to assess the failure of beam-to-column steel joints under seismic loading, via low-cycle fatigue approaches, which have been recently proposed and validated with reference to steel components (members and joints) under cyclic loading. The considered approaches are based on the selection of a suitable parameter (S) capable to represent the global joint behavior and require the experimental definition of S-N (number of cycles at collapse) fatigue resistance curves on the basis of cyclic loading histories, which have to be suitably selected. Design analysis of frames in seismic zones is allowed by means of two alternative methods: nonlinear dynamic analysis under real or synthetic accelerograms, and linear dynamic analysis to verify the safety of the structure based on its response to a design spectrum.