SEISMIC RESPONSE PREDICTION OF HDR BEARINGS USING FRACTIONAL DERIVATIVE MAXWELL MODEL

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 s hear strain of approximately 200%. The equivalent linear characteristi cs are determined according to AASHTO specifications based on the stea dy-state responses of sinusoidal tests. An equivalent linear analysis is performed to predict the seismic responses of the test structure an d the results are compared with the measured responses. Besides, the f ractional derivative Maxwell model of the bearing is formulated and an explicit integration scheme is implemented for solving the equation o f motion of the test structure subject to ground motions. Two sets of numerical parameters involved in the fractional derivative Maxwell mod el are identified with respect to the best fit to the dynamic amplific ation function and phase angle determined from the sinusoidal tests. A ccording to the comparison of the predicted and measured seismic respo nses of the test structure, it is found that the parameters should be determined from the best fit to the phase angle rather than the dynami c amplification function. For practical applications, the fractional d erivative Maxwell model is equipped with an iteration procedure. (C) 1 998 Elsevier Science Ltd. All rights reserved.