Experimental and numerical investigations on the similitude effect of scaled lead rubber bearings for shaking table test

Small scaled lead rubber bearings (SLRBs) are widely used for shaking table tests in isolated tall buildings. Notably, research on the similitude effect of such bearings has rarely been conducted at the component and overall structural levels. Thus, two types of SLRBs with a diameter of 95 mm were designed according to the post-yield stiffness (i.e., SLRB95-A) and equivalent stiffness (i.e., SLRB95-B) to evaluate the existing design principle for the SLRB in the shaking table tests. At the component level, the mechanical characteristics of the two types of SLRBs were evaluated through vertical compression tests and compression-shear tests, and the effects of critical factors on the mechanical parameters were identified. A more desirable and stable performance was realized for SLRB95-B than for SLRB95-A. At the overall structural level, the seismic performance of the prototype structure and scaled structure using the two types of SLRBs were compared. A better agreement was observed between the distributions of the maximum inter-story drift ratio of the prototype structure and scaled structure using SLRB95-B compared to SLRB95-A. Based on these results, the SLRB is recommended to be designed based on the equivalent stiffness. The research outcome will provide a useful reference for the design of scaled lead rubber bearings for shaking table tests.