Wolski, Ricles, and Sause 2009
There has been extensive research done in past years on SC-MRF. In general a SC-MRF allows for beam-column connects to develop a gap opening under rotational moments, which is countered by a horizontally orientated PT tendon. The connection allows for minimal inelastic deformation in the beam and columns. This paper presents a SC-MRF with a Bottom Flange Friction Device (BFFD).
System Concept
The BFFD is assembled with PT high-strength steel strands running parallel to the beam in order to form a new design for beam-to-column connections. The device is composed of a plate with slotted bolt holes that is shop welded to the beam bottom flange and two other built-up angles that are field bolted to the column. Pressed between both sides of the slotted plate and the two column angles are brass friction plates. Energy dissipation happens during the sliding at the faces of the slotted plate and the brass friction plates.
Two advantages of the proposed system is that it does not interfere with the floor slab and when properly designed would not have to be replaced after an earthquake.
Experimental Study, Results and Discussion
Seven 0.6 scale experimental test were conducted on the SC-MRF with a BFFD. The specimens were subjected to a series of symmetric lateral displacement cyclic cycles. The load was applied to the free end of the beam through an actuator.
The study found that the energy dissipation characteristics were accurately predicted and showed to be reliable. With the PT strands designed to remain elastic and the friction bolts designed to fail in shear after bearing against the ends of the slotted bolt holes, the connection was able to remain damage free under EQ loading.
Reference
Wolski, M., Ricles, J. M., & Sause, R. (2009). "Experimental Study of a Self-centering Beam–Column Connection with Bottom Flange Friction Device." Journal of Structural Engineering, 135(5), 479-488.