Projects and Case Studies | Product Information | Contact SEP
Seismic Bearings
FAQs
- Can you help with design of isolators?
- Do you have a computer program to help us with our design?
- Do you do your own isolator testing?
- What kind of isolators do you produce?
- How does isolation work?
- Do isolators need to be replaced after an earthquake?
- Do the isolators return to their original position after an earthquake?
SEP will assist you in assessing the feasibility of using seismic isolation on your project, as well as aid you in modeling the isolators in your analysis and detailing the connections to the substructure and superstructure. Alternatively, SEP can review your isolator design and provide input on the most economical isolator configurations, testing requirements and specifications. SEP will also work with you to develop alternative isolator geometry for applications with limited space and/or access.
Do you have a computer program to help us with our design?SEP does not distribute computer program for the design of their isolators because the number of variables affecting the design and configuration of isolators prohibits a "black box" program from offering the full spectrum of possibilities. We encourage you to contact us for individualized service.
Do you do your own isolator testing?SEP maintains three testing fixtures, with a capacity of up to 6,000 kips axially and 1000 kips in shear. SEP's equipment is calibrated annually in accordance with ASTM E4 and has been approved for use by all owners for whom SEP has supplied isolators. SEP does not perform dynamic or real-time testing, as this requires specialized equipment most often found at university laboratories.
What kind of isolators do you produce?SEP designs, fabricates and tests lead rubber, high damping and sliding isolation bearings.
How does isolation work?Isolation works by lengthening the fundamental period of the structure, thereby reducing the acceleration input into the building, bridge or equipment. The damping achieved by the isolation system further reduces the acceleration input and reduces the displacements across the isolation system.
Do isolators need to be replaced after an earthquake?No. The isolators are designed, manufactured and tested to withstand numerous design-level events without the need for replacement and with no degradation of properties. Our standard testing includes several fully reversed cycles to validate the performance of the isolators and to permit each isolator to be inspected.
Do the isolators return to their original position after an earthquake?Yes, the post-elastic stiffness, also called the "restoring force" serves to return the isolators to their undeformed position during an earthquake. Analytical studies and shaking table or earthquake simulation tests have both confirmed this effect.