Pall Friction Dampers
Pall Friction Dampers are simple and foolproof in construction. Basically, these consist of series of steel plates, which are specially treated to develop very reliable friction. These plates are clamped together and allowed to slip at a predetermined load. Decades of research and testing have led to perfecting the art of friction. Their performance is reliable, repeatable and they possess large rectangular hysteresis loops with negligible fade. Pall Friction Dampers are passive energy dissipation devices and, therefore, need no energy source other than earthquakes to operate it. They do not require any repair or replacement after the earthquake and are always ready to do their job.

Pall Friction Dampers are available for long slender tension-only cross bracing, single diagonal tension-compression bracing and chevron bracing. The damper for cross bracing is a unique mechanism. When the brace in tension forces the damper to slip, the damper mechanism forces the other brace to shorten and thus avoid buckling. In this manner, the other brace is immediately ready to slip the damper on reversal of cycle. These dampers have been used in 65 feet (22 m) long slender bracing. To avoid pounding at the expansion joints, Pall Friction Connectors are custom made to accommodate bi-directional movements.

Salient features
  • Their performance is independent of velocity and hence exerts constant force for all future earthquakes, design-based earthquake (DBE) or maximum credible earthquake (MCE).
  • A much greater quantity of energy can be dissipated in friction than any other method involving the yielding of steel plates, viscous or viscoelastic dampers. Therefore, fewer Pall Friction Dampers are required to provide the required amount of energy dissipation.
  • In a typical un-damped structure, the inherent damping is merely 1-5% of critical. With the introduction of Pall Friction Dampers, structural damping of 20-50% of critical can be easily achieved.
  • Pall Friction Dampers are customized to suit site conditions and allow greater adaptability than is possible with other systems. These dampers can be bolted or welded into place.
  • Pall Friction Dampers provide a practical, economical and effective approach for the design of structures to resist major earthquakes. Low cost of Pall Friction Dampers suggests wide application for all sectors of society - public, private and developer.
Quality Control

Pall Friction Dampers meet a high standard of quality control. Throughout the entire production process, stringent quality control procedures ensure that the materials as well as the finished product are of the highest order. Once assembled, every Pall Friction Damper is load tested and its performance reviewed by an engineer before shipment.


  1. Introduction of high damping results in reduction of forces and deflections.

  2. Added safety to building, contents and occupants.

  3. Performance based design at low cost.

  4. Saving in cost of new construction (1-2%) and retrofit of existing buildings (30-60%).

  5. Saving in life cycle cost as damage is minimized.

  6. Saving in insurance premiums.