Abstract:
To effectively alleviate the main problems in urban over-track buildings, i.e., the abrupt change of lateral stiffness and discomfort caused by the vertical vibration, laminated thick rubber bearings (TRBs) are gradually used in the earthquake- and subway-induced isolation design of these buildings. Nevertheless, when it comes to multi-story or high-rise over-track buildings, a relatively large vertical loading capacity is required for TRBs, and the tensile stress needs to be examined carefully. Thus, a TRB with the first and second shape factors of 10.3 and 4.0, respectively, was designed, and the compressive and tensile behaviors of this bearing were studied. According to full-scale isolator tests, its mechanical properties in the vertical direction were obtained. The results showed that under a design compressive load each rubber layer bulged evenly and there was no overall lateral buckling. Under tensile loading, even tensile deformation could be found for all rubber layers, and its tensile stress met the code limit. Then, an ABAQUS finite element model for this TRB was built. The Yeoh constitutive relationship was used to simulate the rubber under compression, and it showed that the compressive stiffness of this TRB could be well predicted. To consider the tensile damage of bearings after cavitation into the constitutive relationship of rubber, the UHYPER subroutine was developed. Accordingly, the tensile stiffness and capacity of this isolator could be accurately predicted. Finally, based on experimental and numerical results, the calculation methods for the compressive and tensile stiffnesses and for tensile capacity were developed. The results of this study can provide an experimental and theoretical support for the earthquake- and subway-induced isolation design of TRBs in multi-story or high-rise over-track buildings.