A fractional derivative model to include effect of ambient temperature on HDR bearings

Based on a previous application of the fractional derivative Kelvin model to the seismic response prediction of high damping rubber (HDR) bearings, the effect of ambient temperature is incorporated into the formulation of the model in this study, considering the variation of ambient temperature may significantly influence the mechanical characteristics of the bearings. Shaking table tests are conducted for a test structure composed of a steel deck isolated by four HDR bearings. The bearings were tested at various temperatures ranging from 0 to 28°C. Identified from the results of sinusoidal tests, the effective shear modulus is expressed in terms of maximum shear strain and temperature of the bearing. The numerical constants involved in the fractional derivative Kelvin model are represented by functions of ambient temperature. The extended model is validated by comparing the predicted seismic responses of the test structure with those measured from the earthquake tests conducted at various temperatures.