Self-centering compact damper unit applicable to structures for seismic energy dissipation

Abstract

The damper unit 10 is applicable to structures for seismic energy dissipation. The damper unit 10 comprises, a lower beam 11, an upper beam 12, a left column 21, a right column 22, axially yielding dampers 41, 42 functioning as an energy dissipating means, a left post-tensioned steel bar 31, and a right post-tensioned steel bar 32. The left and right post-tensioned steel bars 31 and 32 are inserted in the left and right columns 21 and 22, respectively. Upper ends of the steel bars 31 and 32 are connected with the upper beam 12. Lower ends of the steel bars 31 and 32 are connected with the lower beam 11. The columns 31 and 32 are semi-rigid connected with the upper beam 12 and the lower beam 11 by compressive forces generated from the steel bars 31 and 32. Therefore, the damper unit 10 possesses both self-centering and seismic energy dissipation characteristics.

1 . A self-centering compact damper unit applicable to structures for seismic energy dissipation comprising:
 a lower beam;   an upper beam disposed in parallel with and opposing to said lower beam at a position apart from said lower beam;   a left column interposed between said lower beam and said upper beam at a left side of said lower beam and said upper beam so as to support said upper beam;   a right column interposed between said lower beam and said upper beam at a right side of said lower beam and said upper beam so as to support said upper beam;   energy dissipating means, disposed in a frame configured by said lower beam, said upper beam, said left column, and said right column, for dissipating seismic energy applied to said frame;   at least a left post-tensioned steel bar, an upper end of said left post-tensioned steel bar being connected with said upper beam at a position close to said left column, and a lower end of said left post-tensioned steel bar being connected with said lower beam at a position close to said left column; and   at least a right post-tensioned steel bar, an upper end of said right post-tensioned steel bar being connected with said upper beam at a position close to said right column, and a lower end of said right post-tensioned steel bar is connected with said lower beam at a position close to said right column.   
     
     
         2 . A self-centering compact damper unit according to  claim 1 , wherein,
 said left column is semi-rigid connected with said upper beam and said lower beam by a compressive force generated by said left post-tensioned steel bar; and   said right column is semi-rigid connected with said upper beam and said lower beam by a compressive force generated by said right post-tensioned steel bar.   
     
     
         3 . A self-centering compact damper unit according to  claim 2 , wherein, said left post-tensioned steel bar is inserted in said left column, and said right post-tensioned steel bar is inserted in said right column. 
     
     
         4 . A self-centering compact damper unit according to  claim 2 , comprising:
 at least a pair of said left post-tensioned steel bars which are apart from said left column at a same distance so as not to interfere with said energy dissipating means during a movement of said energy dissipating means; and   at least a pair of said right post-tensioned steel bars which are apart from said right column at a same distance so as not to interfere with said energy dissipating means during a movement of said energy dissipating means.   
     
     
         5 . A self-centering compact damper unit according to  claim 2 , wherein,
 at least one end portion of an upper end portion of said left column, a lower end portion of said left column, an upper end portion of said right column, and a lower end portion of said right column has a rounded convex shape, and   at least one contact portion of a left upper contact portion of said upper beam, a left lower contact portion of said lower beam, a right upper contact portion of said upper beam, and a right lower contact portion of said lower beam, said at least one contact portion contacting with said at least one end portion, has a rounded concave shape.   
     
     
         6 . A self-centering compact damper unit according to  claim 5 , wherein,
 said rounded convex shape is substantially a part of a hemispherical shape having a first predetermined radius; and   said rounded concave shape is substantially a part of a hemispherical shape having a second predetermined radius larger than said first predetermined radius.   
     
     
         7 . A self-centering compact damper unit according to  claim 5 , wherein,
 said rounded convex shape is substantially a part of a sidewall of a cylinder having a third predetermined radius; and   said rounded concave shape is substantially a part of a sidewall of a cylinder having a fourth predetermined radius larger than said third predetermined radius.   
     
     
         8 . A self-centering compact damper unit according to  claim 2 , wherein,
 at least one end portion of an upper end portion of said left column, a lower end portion of said left column, an upper end portion of said right column, and a lower end portion of said right column is flat, and   at least one contact portion of said left upper contact portion of said upper beam, said left lower contact portion of said lower beam, said right upper contact portion of said upper beam, and said right lower contact portion of said lower beam, said at least one contact portion contacting with said at least one end portion, has a concave shape substantially having a part of a rectangular parallelepiped.   
     
     
         9 . A self-centering compact damper unit according to  claim 1 , wherein,
 said energy dissipating means comprises a first axially yielding damper and a second axially yielding damper,   one end of said first axially yielding damper is connected with either said upper beam at said left side or said left column at a position close to an upper end of said left column;   the other end of said first axially yielding damper is connected with either said lower beam at said right side or said right column at a position close to a lower end of said right column;   one end of said second axially yielding damper is connected with either said upper beam at said right side or said right column at a position close to an upper end of said right column; and   the other end of said second axially yielding damper is connected with either said lower beam at said left side or said left column at a position close to a lower end of said left column.   
     
     
         10 . A self-centering compact damper unit according to  claim 1 , wherein,
 said energy dissipating means comprises a shear panel which is supported by said frame in such a manner that said shear panel is deformed when said frame is deformed by said seismic energy.   
     
     
         11 . A self-centering compact damper unit according to  claim 10 , wherein,
 said shear panel has a planar shape being substantially the same rectangular shape as a shape defined by an inside portion of said frame, and four corners of said shear panel are cut out.   
     
     
         12 . A self-centering compact damper unit according to  claim 2 , wherein
 said left column comprises an upper end portion having a rounded convex shape and a lower end portion having a rounded convex shape;   said right column comprises an upper end portion having a rounded convex shape and a lower end portion having a rounded convex shape;   said lower beam comprises a left lower contact portion having a rounded concave shape on an upper surface of said lower beam at said left side, and a right lower contact portion having a rounded concave shape on said upper surface of said lower beam at said right side, said left lower contact portion contacting with said lower end portion of said left column, and said right lower contact portion contacting with said lower end portion of said right column; and   said upper beam comprises a left upper contact portion having a rounded concave shape on a lower surface of said upper beam at said left side, and a right upper contact portion having a rounded concave shape on said lower surface of said upper beam at said right side, said left upper contact portion contacting with said upper end portion of said left column, and said right upper contact portion contacting with said upper end portion of said right column.   
     
     
         13 . A self-centering compact damper unit according to  claim 12 , wherein,
 said rounded shape of said upper end portion of said left column is a part of a substantially hemispherical shape having a first radius;   said rounded shape of said lower end portion of said left column is a part of a substantially hemispherical shape having a second radius;   said rounded shape of said upper end portion of said right column is a part of a substantially hemispherical shape having a third radius;   said rounded shape of said lower end portion of said right column is a part of a substantially hemispherical shape having a fourth radius;   said rounded concave shape of said left upper contact portion of said upper beam is a part of a substantially hemispherical shape having a radius larger than said first radius;   said rounded concave shape of said left lower contact portion of said lower beam is a part of a substantially hemispherical shape having a radius larger than said second radius;   said rounded concave shape of said right upper contact portion of said upper beam is a part of a substantially hemispherical shape having a radius larger than said third radius; and   said rounded concave shape of said right lower contact portion of said lower beam is a part of a substantially hemispherical shape having a radius larger than said fourth radius.