NEHRP Clearinghouse
- Title
- Earthquake Simulator Testing of a Combined Sliding Bearing and Rubber Bearing Isolation System.
- File
- PB92192962.pdf
- Author(s)
- Kelly, J. M.; Chalhoub, M. S.
- Source
- National Science Foundation, Washington, DC., December 1990, 186 p.
- Identifying Number(s)
- UCB/EERC-87/04
- Abstract
- Essential requirements of a base isolation system include wind restraint, stability, and fail-safe capacity. The report contains a new base isolation system combining sliders and rubber bearings that inherently satisfies all three requirements, and possesses other advantages. The system was tested on the Earthquake Simulator at the University of California at Berkeley by installing it under the base of a one-fourth scale nine-story steel structure and subjecting it to different earthquake inputs. The base behaves as fixed for low magnitude inputs. When sliding starts the rubber bearings provide additional stiffness and recentering. Under very severe inputs the tension devices reach their locking limit and cause a large increase in the stiffness of the system. Areas of base shear hysteresis loops are drastically enlarged by the addition of sliders. The fail-safe capacity is provided by the tension restrainers and by the constant contact of the sliders with the base. The sliders were also tested separately on a static rig. The friction coefficient for teflon-stainless steel increases with sliding velocity and decreases with pressure. Teflon sustains high pressures without remarkable changes in its properties. The main aspect of its wearing is delamination.
- Keywords
- ; Dynamic loads; Seismic waves; Steel structures; Shear stress; Displacement; Hysteresis; Bearings; Rubber; Vibration damping; Vibration isolators; Earthquake resistant structures; Structural vibration; Tetrafluoroethylene resins; Sliding; Simulators; Earthquake resistance; Model tests; Dynamic response; Earthquake engineering