Kim and Christopoulos 2008
The paper is proposed a new Self-Centering Friction (SCFR) connection as a new alternative for PT self-centering steel moment frames. The connection eliminates the weld at the beam-to-column interface and provides energy dissipation. Energy dissipation is provided through a bolt-stressed frictional devices consisting of stainless-steel interfaces and new non-asbestos organic break lining pads. PT high strength bars run parallel to the beam which provides the SC capability.
System Concept
The SCRF is assembly is made up of three main pieces. The PT elements (bars) provide the initial force in the connection. They are anchored outside of the flange faces of the exterior columns and run through the interior column flanges. The frictional energy dissipating devices are located on the top and bottom beam flanges. The last component of the assembly is the backbone frame which consists of the beam and column, providing a capacity envelope for the connection.
As moment is applied to the connection, the initial PT force is overcome and a gap opens at the beam-to-column interface. The PT bars elongate with the widening of the gap and axial shortening of the beam. The opening force is countered by the frictional energy dissipating devices at the top and bottom of the connection. Along with the friction force, the PT bars provide the restoring force and SC capabilities.
Experimental Study, Results and Discussion
The SCFR assembly was experimentally tested for both the exterior and interior beam-column loading within the self-centering range. The interior column assembly was also tested beyond the self-centering range to study the behavior. They were examined under cyclic loading for their structural behavior. The connection exhibited good energy dissipation without beam or column inelastic deformations and without residual story drift. At the ultimate stage, the connection can provide a ductile response with the formation of flexural hinges in the beam sections.
Reference
Kim, H. and Christopoulos, C. (2008). ”Friction Damped Posttensioned Self-Centering Steel Moment-Resisting Frames.” Journal of Structural Engineering, 134.11, pp. 1768–1779.