Post-Northridge Earthquake Seismic Steel Moment Connections

After the 1994 Northridge earthquake a tremendous amount of research activity was generated in the United States. In this paper on introducing the basic concepts of seismic design, and illustrating a typical pre-Northridge earthquake steel connection, the fundamental reasons of the poor behavior of the connections are discussed. Then the development of the so-called Dog Bone connection is brought in. Experimental results on two connections of this type are discussed in detail. The reasons for good behavior of Dog Bone connections are then explained using three-dimensional von Mises yield criterion. This new analytical demonstration provides solid evidence as to why the Dog Bone connections behave well. The problem of torsional instability of these connections is not considered.