| Title | Mechanical Characteristics of Base Isolation Bearings for a Bridge Deck Model Test |
| Authors | Kelly, James M.; Buckle, Ian; Koh, Chan-Ghee |
| Publication | Earthquake Engineering Research Center Report No. UCB/EERC-86/11, November 1987 |
| Objectives | To establish the mechanical properties of natural rubber and lead rubber bearings by single-bearing and shake-table tests, and compare these properties with theoretical predictions. |
| Abstract | This report describes the mechanical characteristics of rubber bearings designed for a base isolated bridge deck model which represents a typical highway bridge superstructure. Two different forms of isolation system were used in the test program. The first set of isolators were elastomeric bearings made from natural rubber layers and reinforced with steel plates. The second set of isolators were also elastomeric bearings of the same construction as the first set but with a lead plug on a vertical axis to enhance damping. To satisfy the dynamic similitude laws for the model, the bearings were unusually slender by current code specifications and outside the range of height-to-width ratios commonly accepted for stability of elastomeric bearings in the United States. Static compression and shear tests, cyclic shear tests at different compression loads, and a series of shaking table tests were undertaken at the Earthquake Engineering Research Center of the University of California at Berkeley to establish fundamental stiffnesses, buckling loads and dynamic performance of the bearings. Of particular interest is the confirmation of theoretical predictions of the static stiffnesses, the buckling load, and the limiting shear displacement defining the onset of overturning instablity. |
