Experimental study of sliding isolated structures with uplift restraint

An experimental study, performed to evaluate the feasibility of using a sliding isolation system with uplift restraint devices for medium-rise buildings subject to column uplift, is presented. A Teflon-disc sliding bearing with built-in uplift restraint devices is described. A quarter-scale, 52-kip (231-kN) model of a six-story structure was isolated using the sliding isolation system with uplift restraint devices. The model had a slender configuration with ratio of height to width of 4.5. The slender configuration was chosen to ensure column uplift. Shake-table tests, involving strong motions with different frequency contents and peak table accelerations as high as 0.6 g, were performed. The shake-table test results show that the sliding isolation system is effective in reducing the structural response and uplift forces, by reducing the lateral floor accelerations and overturning moments, and that the uplift restraint system is effective in resisting uplift forces. An analytical model for predicting the response is developed. Comparisons between the predicted and observed responses are presented.