What the bearing consists of
A slider with an anti-friction coating moves along the concave spherical surface of a steel plate. An articulation transfers the load from the building and allows rotation.
The period is set by the radius, not the mass
In shear, the slider rises along the spherical surface, and the building's weight creates a restoring force — as in a pendulum. The vibration period is determined by the radius of curvature of the surface: T = 2π√(R/g), and does not depend on building mass.
Energy is dissipated by friction on the sliding surface. Because the horizontal stiffness of the bearing is proportional to the load on it, the centre of stiffness of the system coincides with the centre of mass — this reduces torsion of the building.
Where FPS bearings are used
Buildings with uneven mass distribution
The centre of stiffness follows the centre of mass — less torsion.
Hospitals
Buildings that must remain operational after an earthquake.
Bridges and infrastructure
Isolation bearings for bridge superstructures — based on a separate analysis.
Strengthening and reconstruction
Seismic isolation or dampers in existing buildings based on a separate analysis.
Advantages
Limitations and considerations
Key bearing parameters
Values are determined for the specific building from the structural model and the input data. There is no universal selection table.
| Parameter | Symbol | Unit | Value |
|---|---|---|---|
| Design vertical load | P | kN | per project |
| Radius of curvature of the surface | R | mm | per project |
| Friction coefficient | μ | — | per project |
| Design displacement | D | mm | per project |
| Plan dimensions × height | L × H | mm | per catalogue |
Certificates and technical materials
The Safetyinside FPS catalogue, certificates and test reports are available on request — we will send documents for your project.
Request documentsFrequently asked questions about FPS bearings
How does a pendulum bearing differ from a laminated rubber bearing?
In laminated rubber bearings (LRB, LNR, HDRB) flexibility comes from the rubber; in FPS bearings, from sliding on a spherical surface. In an FPS bearing the period is set by the radius of curvature and does not depend on building mass.
Will the building return to its original position?
The building's weight and the surface curvature create a restoring force, but friction may leave a small residual displacement. Its magnitude is estimated by analysis.
What data is needed for preliminary selection?
General information about the building, architectural and structural drawings, geotechnical data, loads and, if available, an ETABS or LIRA-SAPR model.
How much do FPS bearings cost?
The cost depends on the number and parameters of the devices and is determined after preliminary selection. We do not publish fixed prices.
Request a preliminary selection of FPS bearings
Specify the building type, number of storeys and project stage and attach your materials — an engineer will prepare a preliminary solution.