Ikenaga 2006
In this paper, self-centering column bases are presented to show that reduction occurs in their residual deformation. Self-centering system joints can reduce the residual deformation; however, if column bases sustain large plastic deformation, it is likely that residual deformation will not be suppressed adequately. Therefore, self-centering column bases are developed using a PC bar and steel damper.
System Concept
Self-centering column bases are composed of a PC bar, steel damper and grade beam. The wide flange steel column is placed on the top of grade beam, with a pair of PC bars connecting the column and beam. The ends of the PC bars were supported by the bottom flange of the grade beam at the bottom and the horizontal stiffener of column at the top. These supporting locations of the column and beam were reinforced by stiffeners. The column base begins to rotate when one flange is decompressed by bending. This causes the system to behave as a pin. Since the damper is attached to the column base the system possesses additional strength, stiffness and energy-dissipating capabilities after decompression.
Analytical Study, Results, and Discussion
A static pushover analysis and dynamic analysis were performed to confirm the theory that energy dissipation and increased stiffness and strength will result from the use of PC bars at the base of columns. The static analysis yielded behavior of the structure that was stable for both positive and negative deformation and several repetitions. The stiffness and moment from the dynamic analysis were similar to those predicted by the static analysis.
Reference
Ikenaga, M. (2006). “Self-Centering Column Base Analysis,” Disaster Prevention Research Institute, Kyoto University, Kyoto, Japan.