Experimental Investigation of Hysteretic Performance of Self-Centering Glulam Beam-to-Column Joint with Friction Dampers

Abstract

In this study, friction dampers (FDs) were placed at the top and bottom of a post-tensioned (PT) self-centering glulam (SCG) beam-to-column joint to dissipate earthquake energy. PT tendons were installed in two externally elongated slots at the centroid of the beam to provide the system with self-centering capacity so that the system can return to its original position after an earthquake. Theoretical and experimental analyses of the beam-to-column joint were performed to investigate the effects of various design parameters, such as the total clamping forces applied to the FDs and initial forces of the PT tendons, on the hysteretic performance of the FD-SCG joint under cyclic loading. During the tests, the backbone members (glulam beam and column) and main connecting members (PT tendons and FDs) were measured to always be within the elastic limit range. Both the theoretical and experimental results indicated that under low initial PT forces and clamping forces, the energy is dissipated primarily by FDs; in contrast, under high PT forces and clamping forces, some energy is dissipated by the glulam materials, owing to the occurrence of minor local damage in the specimen, in the direction perpendicular to the grain. Moreover, the FD-SCG joint can be suitably designed to achieve the desired stiffness, load capacity, self-centering ability, energy dissipation capability, and expected overall system response.