Design of a Tridirectional Reaction Frame for Comparative Dynamic Testing of BaseIsolation Systems

摘要

This report presents the results of review, analysis, and design work addressingthe development of a reaction frame for tridirectional testing of base isolation assemblies and a detailed program for the comparative testing of base isolation systems. This first phase of a multiphase research program produced documentation of a reaction frame for the three-dimensional dynamic testing of 1/3 to 1/2 scale seismic isolation units. Factors limiting the scale of the isolation units were (1) the capacity of existing servo-hydraulic actuators at the proposed test site and (2) the capacity of the site's hydraulic systems. The proposed testing program would thoroughly investigate the tridirectional behavior of several base isolation systems. Characteristics to be evaluated and compared would include frequency dependence, stiffness as a function of shear strain, energy dissipation as a function of shear and axial strain, and isolator stability as a function of axial force and shear strain. The program would also use a 1,000 kip compression/tension testing machine to investigate the tensile strength of elastomeric isolators and the vertical energy dissipation characteristics of the various isolation systems at high levels of axial strain. The final design of the isolation units will be addressed during the next phase of the research program. Base isolation systems, Reaction frame, Servo-hydraulic actuators, Tridirectional reaction frame earthquake hazard mitigation engineering.