Compressive Stiffness Verification of Stirrup Rubber Bearing

In recent years, there has been an immense amount of interest in utilizing the rubber bearing system as a practical approach to seismic-resistant design. The stirrup rubber bearing is confined and bonded by stirrup equipments so as to restrict the lateral expansion of the rubbers due to axial load and increase the compression stiffness. Based on two kinematics assumptions that the horizontal plane parallel to the stirrup equipments or rigid bounding steel plates remains plane and the vertical lines become parabolic after loading, the pressure function and compression stiffness for the stirrup rubber bearing are derived. A good agreement between experimental results by the component tests and computational results by the proposed formulae has been obtained.