scope:

A test program consisting of 12 full size specimens was recently completed which had as its objective the investigation of various welded andlor bolted symmetrically-loaded moment-resisting beam-to-column connections. These connections are of importance in the design and construction of steel multi-story frames. All specimens were fabricated of ASTM A572, Grade 55 steel. This report discusses the results of tests on four specimens of moment resisting bolted connections. All bolts were high strength bolts. In three specimens bolts were designed to be in bearing and in one specimen bolts were designed to make the connection slip resistant (friction). Test results show that the bearing type bolted connections initially behave similarly to fully-welded connections of previous tests. However, at a certain "slip" load, the bolted connections exhibit a distinct difference from the welded connections in overall behavior. The "slip" load at which this occurs can be predicted for the specimens tested in this study. The maximum load-carrying capacity of bolted connections is found considerably higher than that of welded connections. Against the background of these results, new design procedures for shear plate, moment plate, column web stiffners and their welding requirements to column web are suggested. These new procedures provide good correlation with the test results