Energy dissipation at PR frames under seismic loading

The major sources of energy dissipation, lateral deformation, and base shear in steel frames with partially restrained (PR) connections subjected to seismic loading are analytically studied. The analytical study confirms, in general, the behavior observed during experimental investigation: PR connections reduce the overall stiffness of frames, but add a major source of energy dissipation. It is observed, in general, that the maximum total base shear may significantly increase as the connection stiffness increases. The maximum top lateral displacement does not always increase with a decrease in the connection stiffness. The response under earthquake loading largely depends on the dynamic characteristics of both the structure and the earthquake excitation. Proper consideration of the stiffness of the PR connections and other dynamic properties is essential to predict the dynamic behavior, no matter how difficult the analysis procedure becomes.