Adjustable cross-frame assembly and method of use thereof

Abstract

An adjustable cross-frame assembly includes a first elongate flexible line, a second elongate flexible line, and an adjustable-length jack assembly. The first elongate flexible line is coupled in tension to a first portion of a first girder and to a second portion of a second girder. The first elongate flexible line extends concurrently with a plane that intersects both of the first and second girders. The second elongate flexible line is coupled in tension to a second portion of the first girder and to a second portion of the second girder. The second elongate flexible line extends concurrently with the plane. The adjustable-length jack assembly is coupled to the first portion of the first girder and to the second portion of the second girder. The adjustable-length jack assembly extends concurrently with the plane.

What is claimed is: 
     
         1 . An adjustable cross-frame assembly for installing cross-frames between girders, the adjustable cross-frame assembly comprising:
 a first elongate flexible line coupled in tension to a first portion of a first girder and to a first portion of a second girder, the first elongate flexible line extending in a direction approximately parallel with a plane intersecting the first and second girders;   a second elongate flexible line coupled in tension to a second portion of the first girder and to a second portion of the second girder, the second elongate flexible line extending in a direction approximately parallel with the plane; and   an adjustable-length jack assembly coupled to the first portion of the first girder and to the second portion of the second girder, the adjustable-length jack assembly extending in a direction approximately parallel with the plane.   
     
     
         2 . The adjustable cross-frame assembly of  claim 1 , further comprising a first chain fall including the first elongate flexible line and a second chain fall including the second elongate flexible line. 
     
     
         3 . The adjustable cross-frame assembly of  claim 2 , wherein the adjustable-length jack assembly includes a hydraulic jack. 
     
     
         4 . The adjustable cross-frame assembly of  claim 3 , wherein the hydraulic jack includes a double-acting hydraulic cylinder. 
     
     
         5 . The adjustable cross-frame assembly of  claim 4 , wherein the adjustable-length jack assembly includes a variable-length pipe strut. 
     
     
         6 . The adjustable cross-frame assembly of  claim 1 , wherein each of the first elongate flexible line and the second elongate flexible line includes a cable. 
     
     
         7 . The adjustable cross-frame assembly of  claim 1 , wherein each of the first elongate flexible line, the second elongate flexible line, and the adjustable-length jack assembly is bolted to both of the first and second girders. 
     
     
         8 . The adjustable cross-frame assembly of  claim 7 , wherein
 each of the first and second girders includes plates coupled thereto, and   each of the first elongate flexible line, the second elongate flexible line, and the adjustable-length jack assembly is coupled to one or more of the plates.   
     
     
         9 . The adjustable cross-frame assembly of  claim 1 , further comprising a plurality of clamp brackets configured to removably couple each of the first elongate flexible line, the second elongate flexible line, and the adjustable-length jack assembly to the first and second girders. 
     
     
         10 . An adjustable cross-frame assembly for installing cross-frames between girders, the adjustable cross-frame assembly comprising:
 a first elongate rigid beam coupled to a first portion of a first girder and to a first portion of a second girder, the first elongate rigid beam extending in a direction approximately parallel with a plane intersecting the first and second girders;   a second elongate rigid beam coupled to a second portion of the first girder and to a second portion of the second girder, the second elongate rigid beam extending in a direction approximately parallel with the plane; and   an adjustable-length jack assembly coupled to the first portion of the first girder and to the second portion of the second girder, the adjustable-length jack assembly extending in a direction approximately parallel with the plane.   
     
     
         11 . The adjustable cross-frame assembly of  claim 10 , wherein each of the first elongate rigid beam and the second elongate rigid beam includes a threaded rod. 
     
     
         12 . The adjustable cross-frame assembly of  claim 11 , wherein the adjustable-length jack assembly includes a hydraulic jack. 
     
     
         13 . The adjustable cross-frame assembly of  claim 12 , wherein the hydraulic jack includes a double-acting hydraulic cylinder. 
     
     
         14 . The adjustable cross-frame assembly of  claim 13 , wherein the adjustable-length jack assembly includes a variable-length pipe strut. 
     
     
         15 . The adjustable cross-frame assembly of  claim 10 , further comprising a plurality of clamp brackets configured to removably couple each of the first elongate rigid beam, the second elongate rigid beam, and the adjustable-length jack assembly to the first and second girders. 
     
     
         16 . The adjustable cross-frame assembly of  claim 10 , wherein
 each of the first and second girders includes plates coupled thereto, and   each of the first elongate rigid beam, the second elongate rigid beam, and the adjustable-length jack assembly is coupled to one or more of the plates.   
     
     
         17 . The adjustable cross-frame assembly of  claim 10 , wherein the first portion of the first girder includes an upper third of the first girder, the first portion of the second girder includes an upper third of the second girder, the second portion of the first girder includes the lower third of the first girder, and the second portion of the second girder includes the lower third of the second girder. 
     
     
         18 . A method of installing cross-frames between girders, the method comprising:
 coupling a first elongate member of a fixed length to a first portion of a first girder and to a first portion of a second girder, such that the first elongate member extends in a direction approximately parallel with a first plane intersecting both of the first and second girders;   coupling a second elongate member of a fixed length to a second portion of the first girder and to a second portion of the second girder, such that the second elongate member extends in a direction approximately parallel with the first plane;   coupling an adjustable-length jack assembly to the first portion of the first girder and to the second portion of the second girder, such that the adjustable-length jack assembly extends in a direction approximately parallel with the first plane, the adjustable-length jack assembly including a variable-length strut and a jack;   adjusting a length of the adjustable-length jack assembly by actuating the jack, thereby rotating at least one of the first and second girders to make the first and second girders locally approximately parallel with each other;   installing a cross-frame coupling the first and second girders together; and   removing the first elongate member, the second elongate member, and the adjustable-length jack assembly from the first and second girders.   
     
     
         19 . The method of  claim 18 , further comprising
 coupling the first elongate member to a first portion of the first girder and to a first portion of the second girder, such that the first elongate member extends in a direction approximately parallel with a second plane intersecting both of the first and second girders at another position along a length of the first and second girders;   coupling the second elongate member to a second portion of the first girder and to a second portion of the second girder, such that the second elongate member extends in a direction approximately parallel with the second plane;   coupling the adjustable-length jack assembly to the first portion of the first girder and to the second portion of the second girder, such that the adjustable-length jack assembly extends in a direction approximately parallel with the second plane;   adjusting a length of the adjustable-length jack assembly by actuating the double-acting hydraulic jack;   installing another cross-frame coupling the first and second girders together; and   removing the first elongate member, the second elongate member, and the adjustable-length jack assembly from the first and second girders.   
     
     
         20 . The method of  claim 18 , wherein
 the first plane intersects both of the first and second girders at a location where at least one of a differential vertical deflection and a differential rotation of the first and second girders is greatest under a steel dead load with the first and second girders supported in a manner substantially identical to a cross-frame installation condition.   
     
     
         21 . The method of  claim 18 , wherein
 the cross-frame is designated as a first cross-frame,   the first cross-frame is installed on a first side of the first plane, and   a second cross-frame is installed on a second side of the first plane opposite the first side.   
     
     
         22 . The method of  claim 18 , wherein
 the first plane intersects both of the first and second girders at a location, and   the first cross-frame is installed between the first plane and a boundary condition.