Steel plate damper for structures

Abstract

Method, apparatus, and systems are disclosed for damping the movements of structures undergoing dynamic forces. The disclosed dampers are a new type of steel plate dampers, intended to reduce the cost and improve the performance of structures subject to severe seismic loading. While in these dampers the metal plates undergo plastic deformation as a method of absorbing and dissipating energy, the disclosed designs do not allow the stress and strain in the metal plates to go above a predetermined design value and; therefore, the new dampers have long lives and do not need repair or replacement after a big earthquake or similar events. These dampers may be used for building and non-building structures. In such applications the required damping capacities are relatively high and different scales of sliding force and stroke are required.

What is claimed is: 
     
         1 . A damper to be attached to members of a building or of a structure that undergoes dynamic loads, the damper comprising:
 a U-shape metal plate (“U-plate”) characterized by a first and a second flat section connected to each other by a curved section of the U-plate, wherein the first and the second flat sections of the U-plate are substantially parallel to each other and wherein a concave side of the curved section of the U-plate faces an area between the first and the second flat sections of the U-plate;   a solid or a hollow cylinder, kept between the first and the second flat sections and longitudinally adjacent to the curved section of the U-plate, wherein a movement of the first and the second flat sections of the U-plate relative to each other causes the U-plate to deform and absorb energy; and   wherein the U-plate is attached to the building or the structure by the first and the second flat sections.   
     
     
         2 . The damper of  claim 1 , wherein the first flat section of the U-plate is attached to a first member of the building or the structure and the second flat section of the U-plate is attached to a second member of the building or the structure and wherein a dynamic movement of the building or the structure causes a substantially parallel movement of the first and the second flat sections of the U-plate relative to each other. 
     
     
         3 . The damper of  claim 1 , wherein the U-plate is made of one metal plate or from layers of metal plates with equal or different thicknesses. 
     
     
         4 . The damper of  claim 1 , wherein the U-plate is made of layers of metal plates from same or different metals. 
     
     
         5 . The damper of  claim 1 , wherein the curved section of the U-plate is a half-hollowcylinder. 
     
     
         6 . The damper of  claim 1 , wherein the attachments of the flat sections of the U-plates to members of the building or structure are fix attachments and/or moveable attachments. 
     
     
         7 . The damper of  claim 6 , wherein members of the building or the structure have slotted holes for movable attachments and wherein attachment pin(s) of some flat sides of some U- plates enter slotted holes of the member of the building or the structure and engage the slotted holes after the members of the building or the structure move relative to each other and wherein lengths of slotted holes determine necessary amount of relative movement of the members of the building or the structure before engagement. 
     
     
         8 . The damper of  claim 1 , wherein multiple dampers are arranged in a line formation between the two members of the building or the structure.