Investigation of Vertical Stiffness in Laminated Thick Rubber Bearings: Theoretical Derivation and Experimental Evaluation Under Varied Loading Conditions

Addressing vibrations induced by rail transit is essential for maintaining structural integrity and enhancing occupant comfort, which is a critical consideration in the architectural design of buildings proximal to rail systems. Previous research has shown that laminated thick rubber bearings (LTRBs) are highly effective in reducing vertical vibrations. An established method to improve their vibration isolation capabilities is to increase the thickness of the rubber layer, which lowers the vertical stiffness of the bearings. However, detailed studies on the behavior of LTRBs under various conditions, such as different vertical compressive stresses, cyclic loading amplitudes and preloading creep, are still limited. Accordingly, this study initially develops a theoretical model to calculate the vertical stiffness of LTRBs. It conducts experimental evaluations on a custom-designed LTRB with a 600[Formula: see text]mm diameter. These experiments examine the impact of different vertical compressive stresses, cyclic loading amplitudes and the effects of precompression and its duration on the bearing’s vertical compressive properties. The findings indicated that vertical compressive stiffness increases with higher vertical compressive stress but decreases with larger loading amplitude. Preloading enhances vertical compressive stiffness compared to conditions without preloading, underscoring the critical importance of bearing creep in stiffness variation. A comparison of theoretical calculations with experimental results shows that the vertical compressive stiffness of thick-laminated rubber bearings aligns closely at [Formula: see text]% and [Formula: see text]% loading amplitudes with deviations within [Formula: see text]%. This study clarifies the changes in vertical stiffness of LTRBs under diverse loading scenarios and confirms the accuracy of the proposed theoretical stiffness calculation model.