Cyclic Loading of Steel Beams and Connections

During a seismic disturbance structural members and their joints are subjected to cyclic excitations. These cyclic excitations may be of such great magnitude that some regions of the members and connections are forced to behave inelastically. In this manner the input energy is absorbed and dissipated. In this paper some experimental work on the effect of cyclic loadings on the behavior of large structural steel cantilevers and their connections is described, and the results are evaluated. One of the important comparisons pursued in the study is between all-welded beam-to-column connections and connections with welded flanges and bolted webs. In addition, the paper proposes a simple bilinear moment-curvature relationship for beams under cyclic loading. This relationship should prove useful in dynamic analysis of structural steel frames subjected to earthquake loadings.