Seismic response prediction of HDR bearings using fractional derivative Maxwell model

Abstract

Shaking table tests are conducted for one type of high damping rubber (HDR) bearing in this study. The bearing is strained up to a maximum shear strain of approximately 200%. The equivalent linear characteristics are determined according to AASHTO specifications based on the steady-state responses of sinusoidal tests. An equivalent linear analysis is performed to predict the seismic responses of the test structure and the results are compared with the measured responses. Besides, the fractional derivative Maxwell model of the bearing is formulated and an explicit integration scheme is implemented for solving the equation of motion of the test structure subject to ground motions. Two sets of numerical parameters involved in the fractional derivative Maxwell model are identified with respect to the best fit to the dynamic amplification function and phase angle determined from the sinusoidal tests. According to the comparison of the predicted and measured seismic responses of the test structure, it is found that the parameters should be determined from the best fit to the phase angle rather than the dynamic amplification function. For practical applications, the fractional derivative Maxwell model is equipped with an iteration procedure.