Define Friction Pendulum Bearing?

In friction pendulum bearings, the lateral displacement is permitted at the interface of the bearing element between the superstructure and the substructure. Lateral movement at a sliding surface is associated with friction forces that oppose movement.

Figure: Friction Pendulum Bearing

The value of the friction force depends on variation factors, including the vertical reaction at the sliding surface, contact pressure, ambient temperature, speed of the movement and the condition of the sliding surface. As shown in Figure, the relative displacement between the sliding interfaces is u₁ - u₂ and the potential energy Vg due to gravity accumulated during the lift-up is

where W is the weight supported by the bearing, R is the radius of curvature of the sliding surface as depicted in Figure. The friction force between the sliding interfaces plays the roll of energy dissipation during the sliding motion.