Yielding link, particularly for eccentrically braced frames

Abstract

A structural yielding link, particularly for use in an eccentrically braced frame arrangement or in a linked column frame arrangement having a first end having a means for connecting to a face of a first beam and a second end having a means for connecting to a face of a second beam; a first variable cross-section portion and a second variable cross-section portion extending from the first end and from the second end, respectively; and a constant cross-section portion joining the first variable cross-section portion and the second variable cross-section portion.

What is claimed is: 
     
         1 . A structural yielding link comprising:
 a first end having a means for connecting to a face of a first beam or column and a second end having a means for connecting to a face of a second beam or column;   a first variable cross-section portion and a second variable cross-section portion extending from said first end and from said second end, respectively;   a constant cross-section portion joining said first variable cross-section portion and said second variable cross-section portion.   
     
     
         2 . The structural yielding link according to  claim 1  for use in an eccentrically braced frame arrangement or in a linked column frame arrangement. 
     
     
         3 . The structural yielding link according to  claim 1 , wherein said first and said second variable cross-section portions are hollow along at least a portion of lengths thereof. 
     
     
         4 . The structural yielding link according to  claim 1 , wherein said first variable cross-section portion and said second variable cross-section portion have a cross-section tapering from said respective first and second end portions towards said constant cross-section portion such that a width of said first and second variable cross-section portions at said respective first and second end portions is greater than a width at said constant cross-section portion. 
     
     
         5 . The structural yielding link according to  claim 4 , wherein said first and said second variable cross-section portions are hollow and have an interior wall thickness which is greater at said first and second end portions, respectively than proximate said constant-cross section portion. 
     
     
         6 . The structural yielding link according to  claim 1 , wherein said variable cross-section portions are designed, sized and otherwise dimensioned to promote near simultaneous yielding along a substantial portion of the yielding link when subjected to a linearly varying bending moment diagram. 
     
     
         7 . The structural yielding link according to  claim 1 , wherein said first and said second variable cross-section portions have a width defined by a higher-order function; whereby said higher-order function promotes yielding of the link when the link is subjected to load(s) causing a linearly varying bending moment diagram. 
     
     
         8 . A structural link according to  claim 1 , wherein said first and said second variable cross-section portions are defined such that the cross sectional area along the length of the link is constant; whereby said constant cross sectional area promotes a constant axial strain along the length of the link when the link is subjected to any axial load. 
     
     
         9 . A structural link according to  claim 8 , wherein said constant cross sectional area is achieved by a flange located at the flexural neutral axis of the cross section. 
     
     
         10 . The structural yielding link according to  claim 1 , further comprising a transition region between said first and second ends and said first and second variable cross-section portions, respectively; where said transition region includes a thickened material portion for limiting stress and strain occurring during yielding of the link from propagating to said means for connecting to said end faces of said first and second beams. 
     
     
         11 . The structural yielding link according to  claim 1 , wherein said variable cross-section portions are designed, sized and otherwise dimensioned to promote yielding along a substantial portion of the yielding link. 
     
     
         12 . The structural yielding link according to  claim 4 , wherein said first and said second variable cross-section portions are hollow and have an interior wall thickness which is constant throughout said first and second variable cross-section portions. 
     
     
         13 . The structural yielding link according to  claim 1 , wherein said first variable cross-section portion and said second variable cross-section portion have a cross-section tapering from said respective first and second end portions towards said constant cross-section portion such that a depth of said first and second variable cross-section portions at said respective first and second end portions is greater than a depth at said constant cross-section portion. 
     
     
         14 . An eccentrically braced frame arrangement comprising
 a first column and a second column;   a beam connecting said first column and said second column; said beam having a first portion connected to said first column, a second portion connected to said second column and a yielding link connecting said first portion and said second portion;   at least one brace having a node end connected proximate an end of said first column and another end connected to an end of said first portion proximate said yielding link;
 wherein said yielding link comprises
 a first end having a means for connecting to an end face of said first portion and a second end having a means for connecting to an end face of said second portion; 
 a first variable cross-section portion and a second variable cross-section portion extending from said first end and from said second end, respectively; 
 a constant cross-section portion joining said first variable cross-section portion and said second variable cross-section portion. 
 
   
     
     
         15 . The eccentrically braced frame arrangement according to  claim 14 , wherein said first and said second variable cross-section portions are hollow along at least a portion of lengths thereof. 
     
     
         16 . The eccentrically braced frame arrangement according to  claim 14 , wherein said first variable cross-section portion and said second variable cross-section portion have a cross-section tapering from said respective first and second end portions towards said constant cross-section portion such that a width of said first and second variable cross-section portions at said respective first and second end portions is greater than a width at said constant cross-section portion. 
     
     
         17 . The eccentrically braced frame arrangement according to  claim 16 , wherein said first and said second variable cross-section portions are hollow and have an interior wall thickness which is greater at said first and second end portions, respectively than proximate said constant-cross section portion. 
     
     
         18 . The eccentrically braced frame arrangement according to  claim 14 , wherein said variable cross-section portions are designed, sized and otherwise dimensioned to promote yielding along a substantial portion of the yielding link. 
     
     
         19 . The eccentrically braced frame arrangement according to  claim 14 , wherein said first and said second variable cross-section portions have a width defined by a higher-order function; whereby said higher-order function promotes yielding of the link when the link is subjected to load(s) causing a linearly varying bending moment diagram. 
     
     
         20 . An eccentrically braced frame arrangement according to  claim 14 , wherein said first and said second variable cross-section portions are defined such that the cross sectional area along the length of the link is constant; whereby said constant cross sectional area promotes a constant axial strain along the length of the link when the link is subjected to any axial load. 
     
     
         21 . An eccentrically braced frame arrangement according to  claim 20 , wherein said constant cross sectional area is achieved by a flange located at the flexural neutral axis of the cross section. 
     
     
         22 . The eccentrically braced frame arrangement according to  claim 14 , further comprising a transition region between said first and second ends and said first and second variable cross-section portions, respectively; where said transition region includes a thickened material portion for limiting stress and strain occurring during yielding of the link from propagating to said means for connecting to said end faces of said first and second beams. 
     
     
         23 . The eccentrically braced frame arrangement according to  claim 14 , wherein said variable cross-section portions are designed, sized and otherwise dimensioned to promote yielding along a substantial portion of the yielding link. 
     
     
         24 . The eccentrically braced frame arrangement according to  claim 16 , wherein said first and said second variable cross-section portions are hollow and have an interior wall thickness which is constant throughout said first and second variable cross-section portions. 
     
     
         25 . The eccentrically braced frame arrangement according to  claim 14 , wherein said first variable cross-section portion and said second variable cross-section portion have a cross-section tapering from said respective first and second end portions towards said constant cross-section portion such that a depth of said first and second variable cross-section portions at said respective first and second end portions is greater than a depth at said constant cross-section portion.