Experimental study of friction damping connections for prefabricated self-centering rocking structural elements

Self-centering rocking structural systems provide solutions for prefabricated buildings to achieve better seismic resilience. A well-designed connection of the self-centering rocking structural elements is critical to provide stable supplemental damping to the system. In this study, an innovative friction damping connection was proposed that could better match the gap-opening-closing motion of the rocking elements. Firstly, prototype experiments were carried out to investigate the connection's mechanical behavior. The brake pad-stainless steel interface exhibited smooth sliding without chatter, stick-slip, or damage. The average static and kinetic friction coefficients were 0.30 and 0.28, respectively, showing negligible dependence on surface pressure, amplitude, or frequency. Then, the proposed connections were applied to the prefabricated shear wall-rocking coupling beam subassembly. Quasi-static cyclic loading tests on 5 full-scale specimens of the subassembly showed typical flagshaped hysteresis curves, and the connections performed well as expected. Moreover, the theoretical analysis accurately reflected the hysteretic behavior of the specimen. Adjusting the connection's frictional force changed the initial damping moment ratio (IDMR) of the coupling beam, determining the rocking system's energy dissipation and self-centering capability. A reasonable IDMR value ranged from 0.8 to 0.9.