The widespread use of sliding bearings occurred in the recent years for the base isolation of buildings and structures requires detailed knowledge of their behavior and improved modeling capability under seismic conditions. A major issue affecting the performance of such devices concerns the generation of frictional heat occurring at the sliding surfaces in presence of high speeds and large friction forces, and the effects of the resulting temperature rise on the properties of the bearing materials; typically, high temperature rises promote a decrease in the coefficient of friction and accelerate the wear of the surfaces through the formation of oxides and surface layers and even local melting.

In this contribution a computational approach is developed to investigate the thermal mechanical behavior of curved surface sliding bearings, e.g. friction pendulum bearings. A three-dimensional finite element model of a sliding bearing is formulated that is capable to accommodate relative movements between the surfaces according to prescribed inputs, and the coefficient of friction of the sliding materials is described as an explicit function of the surface temperature, based upon test data. The generation of frictional heat is reproduced by means of a heat source with intensity dependent on the friction coefficient, the relative speed and the contact pressure at the sliding surfaces. The heat flux and the temperature histories are calculated by the software; a custom sub-routine iteratively adjusts the coefficient of friction on the surface temperature, and this value is used to update the heat flux at each calculation step. The resisting force of the isolator is finally predicted step by step based on the current value of friction.

Various analyses are performed under either unidirectional and multidirectional loading histories and variable axial load, and the accuracy of the predictions is validated by comparison with temperature and force–displacement histories determined in experimental tests on full scale prototypes of the isolator.

The numerical study specifically addresses the assessment of the surface temperatures developed in sliding bearings during earthquakes, with regards to both the relevance to the thermal resistance of the surface materials, and the influence on the stiffness and damping characteristics of the isolator.