Abstract:
A damper brace for use in a rectangular structural building frame pane which pane is defined by interconnecting beams and columns includes a formed rigid triangle having an apex, and a force-adjustable, relative-motion braking structure operatively interposed the rigid-triangle apex and one of the frame beams forming the pane.

Description:
RELATED APPLICATION 
       [0001]    This Application is related to and claims priority from U.S. Provisional Patent Application Ser. No. 60/932,487, filed May 30, 2007, for Frame Damper Bracing, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Plural-story building frames formed with nodally interconnected columns and beams, which define generally rectangular frame planes, experience in such frame planes parallelogram relative-motion distortion as columns bend and beams shift laterally and elastically, i.e., within their respective design limits, relative to one another in the event of a frame-experienced load-force, which is created by ground movement triggered by, for example, an earthquake. Full-moment nodal connections functionable to handle the usually expected earthquake event which creates such frame distortion and resulting swaying movement, and which are designed normally to exert appropriate restoring forces that act to return a frame to its undistorted condition following a natural condition of progressive diminishing oscillating, elastic sway are not particularly effective to dissipate the energy associated with distortional forces within a building frame. This same energy-dissipation limitation is also true of conventional, generally triangular anti-earthquake structures provided for, and extending between, the horizontally disposed beams of a building frame. 
       SUMMARY OF THE INVENTION 
       [0003]    A damper brace for use in a rectangular structural building frame pane which pane is defined by interconnecting beams and columns includes a formed rigid triangle having an apex, and a force-adjustable, relative-motion braking structure operatively interposed the rigid-triangle apex and one of the frame beams forming the pane. 
         [0004]    It is an object of the invention to provide an energy-dissipative bracing structure which dampens distortional forces generated as the result of an earth movement event. 
         [0005]    This summary and object of the invention are provided to enable quick comprehension of the nature of the invention. A more thorough understanding of the invention may be obtained by reference to the following detailed description of the preferred embodiment of the invention in connection with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a side elevation of a dampening structure of the invention incorporated into a building frame, with portions broken away to show detail, and with conventional structural components represented in a somewhat schematic form. 
           [0007]      FIG. 2  is an end-view of a portion of the dampening structure of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0008]    The instant invention augments nodal column/beam connections in a building frame, adding additional bracing, and introducing friction-based, relative-motion, energy-dissipation, by including, within a particular rectangle (or particular rectangles) of a design-selected building-frame pane, a rigid triangular brace which is formed by a pair of upwardly and inwardly inclined rigid legs, whose lower ends are anchored effectively to, and near, the opposites ends of a lower beam in such a pane, and whose upper ends effectively define an upper apex in the brace. The brace is upper-apex-connected to the underside of the relevant overhead beam through a clamping style, clamping-force-adjustable, friction-based, brake-shoe structure, which creates a relative-motion energy-damping connection. 
         [0009]    Referring now to the drawings, a building frame is depicted generally at  10 , and includes spaced columns and I-beams, such as left column  12 , right column  14 , upper beam  16  and lower beam  18 , which pane columns and pane beams form a building frame pane  20 . The corners of the pane include full-moment nodal connections  22 ,  24 ,  26   28  between the respective columns and beams for each pane, wherein the columns and beams are anchored to one another at the nodal connections. 
         [0010]    Within each pane  20  of a building constructed according to the invention, a damper brace  30  is formed. The damper brace includes a pair of elongate, upwardly and inwardly (relative to the pane&#39;s lateral sides) inclined legs  32 ,  34 . The lower end  32   a,    34   a  of each leg is anchored to an anchor or attachment point  36 ,  38 , respectively, to lower beam  18  of pane  20 , adjacent the nodal points  26 ,  28  of connection between lower beam  18  and columns  12 ,  14  for the pane. An upper end  32   b,    34   b  of each leg forms a rigid triangle apex  30   a  of rigid triangle  30  which is located generally centrally below upper beam  16  of each pane, and is attached by suitable fasteners to a brake mechanism  40 , and specifically to a lower brake plate  42  thereof. 
         [0011]    Brake mechanism  40 , seen in detail in  FIGS. 2 , includes the aforementioned lower brake plate  42 , an upper brake plate  44  fixed to a flange  16 a of upper beam  16 , and planarly disposed generally above lower brake plate  42 , a pair of brake shoes  46 ,  48  disposed on opposing sides of brake plates  42 ,  44 , and a pair of clamping plates  50 ,  52  disposed on either side of the brake shoes. Two adjustable nut-and-bolt assemblies  54  extend through clamping plates  50 ,  52 , intermediate brake shoes  46 , 48 , providing force-adjustable clamping for adjusting the damping characteristics of the damper brace and the brake mechanism. Brake shoes  46 ,  48  have cut-outs therein to facilitate insertion of nut-and-bolt assemblies  54 . 
         [0012]    Clamping-force adjustments, which may be screw-thread implemented, are made, per predetermined design parameters, at the time of building frame construction by torque adjustments to nut-and-bolt assemblies  54 . 
         [0013]    With respect to whatever design-tolerance lateral forces, such as seismic forces, may readily be handled without frame damage by the particular column/beam nodal connections in existence in frame  10 , as assisted by the additional bracing provided by the rigid-triangle structure of this invention, those forces will also be appropriately managed without any relative-motion disturbance occurring in mechanism  40 . 
         [0014]    However, in the event of a sufficiently large, frame-experienced load-force, as from an especially strong seismic event, such as the large seismic-induced force illustrated schematically at  56  in  FIG. 1 , a parallelogram-type pane-distortion-displacement  58  takes place which is large enough to overcome frictional resistance furnished within brake mechanism  40 . When this happens, relative motion, to the extent dictated by the level of the seismic force involved, then takes place between lower brake plate  42  and upper brake plate  44 , and heating and resulting energy dissipation occur within mechanism  40  further to resist and tame the strong bending moments then present in pane  20 . With appropriate engineering design in the structure of mechanism  40 , and preferably, initial overall displacement motion of this character, accompanied by frictional energy dissipation within mechanism  40 , the components in frame pane  20  remain within their elastic limits, in other words, to experience only elastic parallelogram distortion. This design consideration is, of course, acted upon with the best knowledge available regarding the expected maximum force and deflection which is anticipated will happen in a particular building-frame location. In the practice of the invention, the particular frame panes wherein the structure of the invention is to be used is entirely a matter of designer choice. 
         [0015]    When a building frame utilizing this invention undergoes such elastic, parallelogram distortion, their occurs a resulting oscillating sway in the frame which is quickly dampened by the relative-motion, energy-consuming, frictional clamping-brake forces that are exerted at the apices of the involved, pane-installed triangular braces—ultimately allowing the building frame pane to return to its original configuration undamaged. 
         [0016]    Thus, a unique frame damper brace for a building frame has been disclosed. It will be appreciated that further variations and modifications thereof may be made within the scope of the invention as defined in the appended claims.