LOW CYCLE FATIGUE BEHAVIOUR OF STRUCTURAL STEEL MEMBERS AND CONNECTIONS

— An experimental study was carried out to investigate the low‐cycle fatigue behaviour of steel beam and beam‐column members, as well as of steel connections, with particular emphasis on beam‐to‐column joints. Several full‐scale specimens were tested, in a multi‐specimen testing program, using constant‐amplitude displacement histories, to develop a cumulative‐damage model. Variable amplitude tests were carried out in order to verify the validity of the proposed model. It is shown that the S‐N curves given by codes for high‐cycle fatigue can be used to interpret the low‐cycle fatigue behaviour of steel members and connections. Miner's rule can be used, together with the previously defined S‐N curves and with a cycle counting method to define a unified cumulative damage model valid for both high and low cycle fatigue. A general failure criterion is proposed which considers the actual energy dissipation through plastic deformation.