Mechanics of Rubber Bearings for Seismic and Vibration Isolation

James M Kelly & Dimitrios A Konstantinidis, University of California at Berkeley, USAJames M Kelly is a Professor in the Graduate School, Department of Civil and Environmental Engineering, Division of Structural Engineering Mechanics and Materials at the University of California at Berkeley, and a Participating Faculty Member at the Earthquake Engineering Research Center, University of California at Berkeley. He has authored over 300 refereed journal papers and 2 books, Earthquake-Resistant Design with Rubber 2nd ed 1996 (Springer Verlag) and Design of Seismic Isolated Structures, 1999, Wiley. He has led the way in experimental investigations of elastomeric seismic isolation bearings by conducting many pioneering studies of seismically isolated structures and structures with energy dissipators. In testing hundreds of bearings he achieved numerous advances, including the application of high-damping rubber for seismic isolation bearings - used in the first U.S. isolated building and in more than 100 structures around the world and the understanding of the dynamic and ultimate behavior of elastomeric seismic isolation at large deformation. Dimitrios A Konstantinidis is a Postdoctoral Researcher on health monitoring at University of California, Berkeley, working on the development and testing of a reliable scheme for monitoring the health of fluid viscous dampers in bridges via wireless communication.

• About the Authors ix Preface xiii1 History of Multilayer Rubber Bearings 12 Behavior of Multilayer Rubber Bearings under Compression 192.1 Introduction 192.2 Pure Compression of Bearing Pads with Incompressible Rubber 192.2.1 Infinite Strip Pad 242.2.2 Circular Pad 252.2.3 Rectangular Pad (with Transition to Square or Strip) 262.2.4 Annular Pad 272.3 Shear Stresses Produced by Compression 302.4 Pure Compression of Single Pads with Compressible Rubber 332.4.1 Infinite Strip Pad 332.4.2 Circular Pad 362.4.3 Rectangular Pad 392.4.4 Annular Pad 403 Behavior of Multilayer Rubber Bearings under Bending 453.1 Bending Stiffness of Single Pad with Incompressible Rubber 453.1.1 Infinite Strip Pad 473.1.2 Circular Pad 483.1.3 Rectangular Pad 493.1.4 Annular Pad 513.2 Bending Stiffness of Single Pads with Compressible Rubber 523.2.1 Infinite Strip Pad 523.2.2 Circular Pad 543.2.3 Rectangular Pad 573.2.4 Annular Pad 584 Steel Stress in Multilayer Rubber Bearings under Compression and Bending 634.1 Review of the Compression and Bending of a Pad 644.2 Steel Stresses in Circular Bearings with Incompressible Rubber 654.2.1 Stress Function Solution for Pure Compression 684.2.2 Stress Function Solution for Pure Bending 714.3 Steel Stresses in Circular Bearings with Compressible Rubber 734.3.1 Stress Function Solution for Pure Compression 734.3.2 Stress Function Solution for Pure Bending 764.4 Yielding of Steel Shims under Compression 784.4.1 Yielding of Steel Shims for the Case of Incompressible Rubber 784.4.2 Yielding of Steel Shims for the Case of Compressible Rubber 795 Buckling Behavior of Multilayer Rubber Isolators 835.1 Stability Analysis of Bearings 835.2 Stability Analysis of Annular Bearings 905.3 Influence of Vertical Load on Horizontal Stiffness 915.4 Downward Displacement of the Top of a Bearing 955.5 A Simple Mechanical Model for Bearing Buckling 1005.5.1 Postbuckling Behavior 1045.5.2 Influence of Compressive Load on Bearing Damping Properties 1065.6 Rollout Stability 1085.7 Effect of Rubber Compressibility on Buckling 1106 Buckling of Multilayer Rubber Isolators in Tension 1136.1 Introduction 1136.2 Influence of a Tensile Vertical Load on the Horizontal Stiffness 1156.3 Vertical Displacement under Lateral Load 1176.4 Numerical Modelling of Buckling in Tension 1206.4.1 Modelling Details 1206.4.2 Critical Buckling Load in Compression and Tension 1227 Influence of Plate Flexibility on the Buckling Load of MultilayerRubber Isolators 1297.1 Introduction 1297.2 Shearing Deformations of Short Beams 1307.3 Buckling of Short Beams with Warping Included 1397.4 Buckling Analysis for Bearing 1467.5 Computation of Buckling Loads 1538 Frictional Restraint on Unbonded Rubber Pads 1598.1 Introduction 1598.2 Compression of Long Strip Pad with Frictional Restraint 1608.3 The Effect of Surface Slip on the Vertical Stiffness of an Infinite Strip Pad 1638.4 The Effect of Surface Slip on the Vertical Stiffness of a Circular Pad 1699 Effect of Friction on Unbonded Rubber Bearings 1779.1 Introduction 1789.2 Bearing Designs and Rubber Properties 1809.3 Ultimate Displacement of Unbonded Bearings 1809.4 Vertical Stiffness of Unbonded Rubber Bearings with Slip on their Top and Bottom Supports 184Appendix: Elastic Connection Device for One or More Degrees of Freedom 193References 209Photograph Credits 213Author Index 215Subject Index 217