Huang, Zhao, Eatherton, and Zhu, 2020
The self-centering beam system is a system in which two lateral beams connected by two vertical columns dissipate seismic energy through frictional damping and retain their self-centering capacity through post-tensioning (PT) strands. This paper observes the self-centering beam (SCB) system against systems without post-tensioning and without frictional damping as subjected to a lateral load test.
System Concept
The Self-Centering Beam (SCB) system focuses on opening and closing gaps between the beam-column interface within the system upon impact of seismic forces in order to dampen the forces without any inelastic damage. Within the system, two horizontal beams are aligned vertically with vertical columns at either end. Four symmetrical post-tensioning (PT) strands work to align the two beams, and two frictional damping mechanisms are on either end of each beam. When acted on by seismic forces, one beam pushes the endplate, which causes a gap between the other beam and the endplate, causing it to, in turn, push the end plate and open the gap in the first beam once again. This cyclical pattern continues, while the friction dampers dissipate seismic energy and the PT strands maintain the self-centering of the system.
Experimental Study, Results, and Discussion
Eleven models were prepared to be tested against a lateral load test. Five of the systems were Self- Centering Beam systems (SCB), two did not have post-tensioning (PT0, and four did not have frictional damping (PTB). The tests were performed in order to determine whether the self- centering beam was a viable system to withstand several earthquakes and dissipate seismic energy with little inelastic deformation. Lateral load tests were performed during several trials in order to simulate several earthquakes acting upon the specimen. An actuator was used to determine displacement history, a load cell determined the post-tensioning forces, and global deformation was determined by displacement meters. It was concluded that the SCB system was viable in self-centering and dissipating seismic energy without global deformation throughout several earthquakes, making it an economic and safe option for performance within structures of several stories.
Reference
Huang, X., Zhao, Z., Eatherton, M., and Zhu, D. (2020). “Experimental Investigation of Self-Centering Beams for Moment-Resisting Frames,” Journal of Structural Engineering, 146. 3, pp. 4.