Verification of friction model of teflon bearings under triaxial load

The writers presented in an earlier paper a mathematical model of friction of sliding bearings under conditions of compression and bidirectional motion. The model could account for the dependence of the coefficient of friction on the velocity and direction of sliding. The model was capable of reproducing the behavior observed in experiments with unidirectional motion, however, no experimental validation of the model was provided for bidirectional motion. The present paper presents experimental results on Teflon sliding bearings under simultaneous compression and high velocity bidirectional motion that provide a complete verification of the presented model. Furthermore, the experimental results show the existence of bidirectional interaction between the orthogonal components of the frictional force at the bearing interface. The importance of these effects is studied in the analysis of an isolated structure. The structure is subjected to a number of pairs of horizontal earthquake excitation components that are representative of seismic zone 4, soil type S₂seismic motion. It was found that neglect of these effects leads to underprediction of the isolation system displacement and overprediction of the structural shear.