Shaking table tests on a scaled multi-story and high-rise glulam frame-concrete core tube hybrid structure

In this study, shaking table tests were performed on a one-sixth-scale eight-story glulam frame-concrete core tube hybrid structure, which consisted of the glulam frame and the concrete core tube with coupling beams. The hybrid structure was subjected to several representative earthquake ground motions with peak ground accelerations (PGA) ranging from 0.07 g to 1.24 g. The seismic responses of the hybrid structure, including acceleration, story displacement, inter-story drift ratio and base shear force distribution, were measured using various types of sensors. The test results revealed that the primary structural damage occurred at the coupling beams, while the glulam frame remained undamaged. The maximum natural frequency was recorded as 3.36 Hz, with a corresponding damping ratio of 11.66%. The acceleration amplification factors of each story ranged from 0.78 to 3.90 and were observed to decrease significantly as the PGA of the seismic excitation increased. The peak inter-story drift ratios under various seismic excitations were observed at the 4th–6th stories, indicating a coupling interaction between the glulam frame and the concrete core tube. The average of peak frame contribution ratio of the model base shear force and base overturning moment under extreme seismic excitations was determined to be 17.50% and 32.08% respectively, suggesting that the seismic loads were predominantly resisted by the concrete core tube. The test findings demonstrated that such a hybrid structure exhibited good seismic performance, providing references for the practical applicability of high-rise timber structures.