A deformation limit state for single plate shear connections subjected to seismic loading

This dissertation focuses on the response of single plate shear connections to seismic loading. Three full size specimens were tested. Each test specimen consisted of a beam to column connection utilizing a single plate shear connection with 3/4 in. (19 mm) diameter A325N high strength bolts. A W398 x 14 column was used for all specimens. The assemblies tested included: a W18 x 55 beam and a three-bolt connection, a W18 x 55 beam and a four-bolt connection, and a W24 x 84 beam and a six-bolt connection. The specimens were each mounted in the load frame at University of Utah Structures Laboratory and subjected to increasing cyclic loads resulting in connection rotations of 0.06 radians. The corresponding connection rotation simulated the rotation demand a single plate shear connection experiences when the frame of which it is a part undergoes lateral displacement during seismic events. The specimens were instrumented to allow the recording of imposed loads, resulting global displacements, and the associated displacements and deformations of the connection components.; When subjected to loading the connections exhibited a rotational stiffness and survivability that was dependent upon connection size. During testing a deformation limit state was observed. The deformation limit state occurred at the fastener located most extreme from the neutral axis of the connection and was associated with the rotation demand imposed upon the connection. The deformation limits for the connections were found to be significantly less than predicted by current theory, and in some cases more critical to connection survivability than the connection limit states associated with gravity loads.; The limit state observed is dependent upon connection size and detailing. Criteria is proposed for the definition of this deformation limit state. An analysis method is developed to predict the resistance of single plate shear connections subjected to rotation demands using the proposed criteria. The dependence of the development of secondary connection strength upon this limit state and the design consequences are discussed.; It is recommended that the proposed deformation limit state criteria and analysis method be used to check the resistance of single plate shear connections in frames when it is anticipated that the frames will undergo lateral deformations resulting in connection rotations. Recommendations are included for the refinement of design details to improve connection performance during seismic events.