Ductile details for welded unreinforced moment connections subject to inelastic cyclic loading

The results of a 3-D finite element study of welded unreinforced flange beam-to-column moment connections in steel special moment resisting frames are presented. Computer models of connection subassemblies were developed using the general-purpose nonlinear finite element program abaqus. Several issues were addressed in the study: (1) geometry and size of the weld access hole; (2) benefit of a welded beam web; (3) control of inelastic panel zone deformations; and (4) effectiveness of continuity plates in reducing local demand on the connection. The analytical results provided information related to basic performance and the effects that these connection parameters have on inelastic cyclic performance, thereby furthering the current understanding of welded moment connection behavior under seismic loading conditions and leading to improved design criteria. Based on the results of the analytical study, recommendations for the seismic design of connections are given. The incorporation of the recommendations into an experimental test program showed good connection ductility in the test specimens.