Patent Publication Number: US-2021189716-A1

Title: Girder tie

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional App. No. 62/950,455, filed Dec. 19, 2019, the entirety of which is hereby incorporated by reference. 
    
    
     FIELD 
     The present disclosure generally relates to girder ties used to resist uplift loads in buildings and other structures. 
     BACKGROUND 
     Girder ties are used to resist uplift loads of building components, such as joists, beams, trusses, etc. Girder ties are commonly used in buildings located in high wind areas (e.g., hurricane or tornado areas) to resist the uplift forces applied to building components by winds blowing into, over, and/or around the building. One conventional type of girder tie connects the building component to a rigid rod that is anchored to a part of the building such as a foundation or a wall. When an uplift force is applied to the building component, the connection between the rigid rod and the girder tie resists the uplift force, holding the building component in position. 
     SUMMARY 
     In one aspect, a girder tie for connecting a building component to a rigid rod to resist uplift forces applied to the building component comprises a connector. The connector includes a building component connector and a rigid rod connector coupled to the building component connector. The rigid rod connector is configured to attach to the rigid rod. The building component connector includes first and second back flanges free of direct connection to one another. The first and second back flanges are each configured to attach to the building component. A washer is configured to be disposed between the rigid rod connector and a nut on the rigid rod that secures the rigid rod to the girder tie. The washer includes at least one back flange brace configured to inhibit the first and second back flanges from moving relative to one another when the building component experiences the uplift forces. 
     In another aspect, a girder tie for connecting a building component to a rigid rod to resist uplift forces applied to the building component comprises a connector. The connector includes a building component connector configured to attach to the building component and a rigid rod connector coupled to the building component connector. The rigid rod connector is configured to attach to the rigid rod. The rigid rod connector is configured to form a moment couple with the rigid rod to resist the uplift forces applied to the building component when the building component experiences the uplift forces. A nut is configured to be threaded onto the rigid rod to secure the rigid rod to the girder tie. 
     Other objects and features of the present disclosure will be in part apparent and in part pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective of a fragmentary portion of a building showing a girder tiedown assembly according to one embodiment of the present disclosure tying a roof truss of the building to a column or stud(s) of the building; 
         FIG. 2  is a perspective of a girder tie of the girder tiedown assembly; 
         FIG. 3  is a perspective of a connector of the girder tie; 
         FIG. 4  is a back side perspective of a washer of the girder tie; 
         FIG. 5  is a top view of a connector blank for forming the connector; 
         FIG. 6  is a top view of a washer blank for forming the washer; 
         FIG. 7  is a front perspective of a fragmentary portion of a building showing a first girder tiedown assembly according to another embodiment of the present disclosure tying a truss of the building to a column or stud(s) of the building; 
         FIG. 8  is a rear perspective the fragmentary portion of the building shown in  FIG. 7  showing a second girder tiedown assembly according to another embodiment of the present disclosure tying the truss to the column or stud(s); and 
         FIG. 9  is a perspective of a girder tie of the second girder tiedown assembly. 
     
    
    
     Corresponding reference characters indicated corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Referring to  FIG. 1 , one embodiment of a girder tiedown assembly constructed according to the teachings of the present disclosure is indicated generally at reference numeral  10 . As shown in  FIG. 1 , the girder tiedown assembly  10  is used to tie or anchor one building component to a supporting member in order to resist any uplift forces that are applied to the building component. In the illustrated embodiment, the girder tiedown assembly  10  is used to tie a roof truss T (e.g., building component) to a stud(s) C of a wall (e.g., supporting member) of the building to counteract any uplift forces that may lift the roof truss generally upward and away from the stud(s). However, it is understood that the girder tiedown assembly  10  can be used to tie generally any type of building component down such as a joist, a beam, another type of truss, a column, etc. It is also understood that the girder tiedown assembly  10  can be used to tie a building component T to support members besides studs C such as columns and concrete walls (e.g., foundation walls). 
     The girder tiedown assembly  10  includes a holdown or anchor  12 , a rigid rod  14  and a girder tie  100 . The holdown  12  is secured to the stud C and the girder tie  100  is secured to the truss T (broadly, building component), with the rigid rod  14  interconnecting the holdown and girder tie to prevent the truss from being lifted relative to the wall. One example of a suitable holdown is the PHD/DTB Holdowns available from MiTek USA, Inc., St. Louis, Mo. Nuts  16  are used to secure the rigid rod to the holdown  12  and girder tie  100 —i.e., the rigid rod is at least partially threaded. The girder tie  100  connects the truss T to the rigid rod  14  to resist the uplift forces applied to the truss. In the illustrated embodiment, the girder tiedown assembly  10  is used with wood frame construction with the rigid rod  14  extending through a top plate B of the wall to interconnect the holdown  12  and the girder tie  100 . The girder tiedown assembly  10  can be used with other types of construction. For example, the girder tiedown assembly  10  can be used to tie the truss T a concrete wall (e.g., supporting member). In that embodiment, the girder tiedown assembly  10  may not include the holdown  12 . Instead, the rigid rod  14  can be embedded in the concrete wall (not shown). 
     Referring to  FIGS. 2-4 , the girder tie  100  includes a connector  102  and a washer  150 . The connector  102  is configured to be attached to the truss T and the rigid rod  14 . The connector  102  includes a building component connector  104  and a rigid rod connector  106 . The building component connector  104  and rigid rod connector  106  are coupled to one another and, more preferably, fixed to one another. The building component connector  104  is configured to attach to the truss T. The building component connector  104  includes first and second back flanges  108  (broadly, at least two back flanges). The first and second back flanges  108  are each configured to attach to the truss T. In one embodiment, the back flanges  108  are sized and shaped to attach to a 2×6 or larger piece of dimensioned lumber. In the illustrated embodiment, each back flange  108  includes a plurality of fastener holes 110 sized and shaped to receive fasteners  18  ( FIG. 1 ), such as screws, bolts, nails, etc., to secure the back flanges and the building component connector  104  to the truss T. The first and second back flanges  108  are free of direct connection to one another. In one embodiment, the first and second back flanges  108  are spaced apart by about 1/16 inch (1.6 mm). However, the first and second back flanges  108  could be touching one another within the scope of the present invention. The first and second back flanges  108  are generally planar, with planar rear surfaces that engage the truss T when the building component connector  104  is secured to the truss T. The back flanges  108  can have generally any shape. Each back flange  108  may also include a notch or opening  118  configured to receive a portion of the washer  150 , as described in more detail below. In the illustrated embodiment, each back flange  108  includes a notch  118  extending from a lower edge margin of the back flange. 
     The orientation of the girder tie  100  in  FIG. 2  provides the point of reference for the terms defining relative locations and positions of structures and components of the girder tie, including but not limited to the terms “upper,” “lower,” “left,” “right,” “back,” “rear,” “front,” as used throughout the present disclosure. 
     The connector  102  includes a flange or rib  112  extending forward from each back flange  108 . In the illustrated embodiment, each rib  112  extends from an inner edge margin (e.g., the edge margin closest to the other back flange) of a corresponding back flange  108 . Each rib  112  interconnects the back flanges  108  and the rigid rod connector  106 . Accordingly, the ribs  112  extend from the back flange  108  to the rigid rod connector  106 . The ribs  112  are generally vertical, when the connector  102  is secured to the truss T. The ribs  112  are generally perpendicular to the back flanges  108 . In the illustrated embodiment, the ribs  112  generally extend along the entire height of the back flanges  108 . The ribs  112  are adjacent to and generally parallel to one another for reasons that will become apparent. In one embodiment, a distance between the ribs  112  is less than or equal to 1/16 inch (1.6 mm). As described in more detail below, the ribs  112  facilitate the bracing of first and second back flanges  108  to inhibit the movement of the first and second back flanges relative to one another when the truss T experiences the uplift forces. The ribs  112  also generally stiffen and strengthen the back flanges  108 . 
     The rigid rod connector  106  is configured to attach to the rigid rod  14 . The rigid rod connector  106  defines a central passage  114  sized and shaped to receive the rigid rod  14 . The rigid rod connector  106  includes a generally cylindrical wall or tube  116  that defines the central passage  114 . The ribs  112  extend from the cylindrical wall  116 . In the illustrated embodiment, the ribs  112  extend from opposite side edge margins of the generally cylindrical wall  116 . Accordingly, in the illustrated embodiment, the cylindrical wall  116  is circumferentially discontinuous. As will become apparent, this discontinuity in the cylindrical wall  116  allows the connector  102  to be stamped from a single sheet of material, as described in more detail below. The rigid rod connector  106  has a height extending from a lower end to an upper end. In one embodiment, the height of the rigid rod connector  106  is about 2⅜ inches (6 cm). In one embodiment, the height of the rigid rod connector  106  is about half of the height of the back flanges  108 . Other configurations of the rigid rod connector  106  are within the scope of the present disclosure. 
     The rigid rod connector  106  is configured to form a moment couple with the rigid rod  14  to resist the uplift forces applied to the truss T when the truss experiences the uplift forces. The rigid rod connector  106  is configured to engage the rigid rod  14  at a minimum of least two longitudinally spaced apart locations on the rigid rod when the truss T experiences the uplift forces to form the moment coupled with the rigid rod. Specifically, upper and lower ends of the rigid rod connector  106  engage the rigid rod  14  to form the moment couple as described in more detail below. 
     By forming a moment couple with the rigid rod  14 , the girder tie  100  is able to resist larger uplift forces than conventional girder ties. Conventional girder ties do not form a moment couple with the rigid rod  14  because conventional girder ties engage the rigid rod at only one longitudinal location. In fact, some conventional girder ties permit the girder tie and rigid rod to pivot relative to one another, which completely prevents any moment couple from forming. 
     When the girder tie  100  is subjected to loads (e.g., uplift forces), the failure mode for the girder tie is being pulled from the truss T. Specifically, the fasteners  18  securing the girder tie  100  to the truss T are pulled out from (e.g., withdraw from) the truss when a sufficient amount of force is applied. When subject to uplift loads capable of causing failure, the nut  16  securing the rod  14  to the girder tie  100  is, in effect, driven down against the top of the cylindrical wall  116  of the rigid rod connector  106 . The force applied to the rigid rod connector  106  is spaced from the back flanges  108  and therefore urges the girder tie  100  generally to pivot or rotate about its lowest most point (or thereabout) that engages the truss T. This movement tends to pry the fasteners  18  out from the truss T. The fasteners  18  resist this withdrawal movement, and the girder tie  100  is constructed to provide substantial additional resistance to pivoting and withdrawal. As the girder tie  100  begins to bend and pivot, the rigid rod connector  106  engages the rigid rod  14  at generally two spaced apart locations, one generally at the upper end of the rigid rod connector and another at the lower end of the rigid rod connector. This forms the moment couple between the rigid rod connector  106  and the rigid rod  14 . Because of the moment couple, in order for the girder tie  100  to continue to pivot and move away from the truss T (e.g., in order for the girder tie to completely fail), the girder tie must bend the rigid rod  14 . Accordingly, the resistance to bending provided by employing the stiffness of the rigid rod  14  increases the amount of the uplift force the girder tie  100  can support over conventional girder ties by reducing the widthdrawal forces applied to the fasteners  18 . 
     The loads applied during uplift can also have a tendency to separate the back flanges  108  from each other in a horizontal direction, which would apply a horizontal shear load to the fasteners  18 , in addition to the vertical shear already being applied. However, the construction of the building component connector  104  inhibits this as well. The position of the force of the rigid rod  14  in relation to the location of the fasteners  18  extending through the back flanges  108  causes the back flanges to move apart. Additionally, the force of the rigid rod  14  against the interior of the cylindrical wall  116  of the rigid rod connector  106  because of the moment couple, also acts to force the back flanges apart. However, referring to  FIGS. 2 and 4 , the washer  150  is configured to be disposed between the rigid rod connector  106  of the connector  102  and the nut  16  on the rigid rod  14  that secures the rigid rod to the girder tie  100 . The washer  150  serves two functions. First, the washer  150  generally distributes the load applied by the nut  16  over the rigid rod connector  106 , like a conventional washer. Second, the washer  150  captures the ribs  112  to inhibit or prevent the first and second back flanges  108  from moving horizontally apart from each other when the truss T experiences the uplift forces, as described in more detail below. 
     As shown in  FIG. 4 , the washer  150  includes an upper flange  152 , a lower flange  154  and a connecting element  156 . The connecting element  156  interconnects the upper and lower flanges  152 ,  154 . The upper flange  152 , lower flange  154  and connecting element  156  are all generally planar. The upper and lower flanges  152 ,  154  are generally parallel with one another and extend rearward from upper and lower edge margins, respectively, of the connecting element  156  to free ends thereof. The upper and lower flanges  152 ,  154  are generally perpendicular to the connecting element  156 . The upper and lower flanges  152 ,  154  each define an aperture or opening  158  sized and shaped to receive the rigid rod  14  through the flange. The openings  158  are aligned (e.g., vertically aligned) with one another and are configured to align with the central passage  114  of the rigid rod connector  106  when the washer is positioned on the rigid rod connector  106 . Accordingly, the upper flange  152  is disposed between the nut  16  and the rigid rod connector  106  when the washer  150  and connector  102  are attached to the rigid rod  14 . 
     The washer  150  includes a back flange brace, generally indicated at  160 , configured to brace the ribs  112  to inhibit the first and second back flanges  108  from moving relative to one another when the truss T experiences the uplift forces. Specifically, the back flange brace  160  inhibits the first and second back flanges  108  from rotating relative to one another, as explained in more detail below. In the illustrated embodiment, the washer includes two back flange braces  160  (e.g., upper and lower back flange braces). Each back flange brace  160  is configured to engage the ribs  112  to prevent the ribs, and therefore the back flanges  108 , from moving apart from one another. Specifically, each back flange brace  160  is configured to inhibit the ribs  112  from moving away from one another (e.g., inhibit the back flanges  108  from moving away from one another). In the illustrated embodiment, the upper and lower flanges  152 ,  154  each define one back flange brace  160 . Each back flange brace  160  includes an open ended slot  162  (e.g., a slot extending from an edge margin of the upper or lower flange  152 ,  154 ). The slots  162  are sized and shaped to receive the ribs  112  therein. Accordingly, the slots  162  are generally aligned (e.g., vertically aligned) with one another. Opposite sides of each slot  162  are defined by bracing tabs  164  (e.g., portions of either the upper or lower flanges  152 ,  154 ). Each bracing tab  164  engages a respective one of the ribs  112  when the ribs are disposed in the slot  162  to prevent the back flanges  108  from moving horizontally apart. 
     In the illustrated embodiment, each bracing tab  164  on the lower back flange brace  160  includes a projection  166  sized and shaped to mate with one of the notches  118  of a corresponding back flange  108 . The projections  166  extend rearward from a rear edge margin of the lower flange  154 . The mating of the projections  166  with the notches  118  facilitates the positioning of the washer  150  relative to the connector  102 , and further prevents the back flanges  108  from moving (e.g., toward or away) relative to one another and helps hold the washer in place relative to the connector when the girder tie  100  is subject to the uplift forces. 
     In operation, the washer  150  is placed on the connector  102  such that the openings  158  of the washer are aligned with the central passage  114  of the connector. In this position, the upper flange  152  of the washer  150  overlies the upper end of the rigid rod connector  106  and the lower flange  154  lies under the lower end of the rigid rod connector. Accordingly, the distance between the upper and lower flanges  152 ,  154  is generally the same as the height of the rigid rod connector  106 . When the washer  150  is positioned on the connector  102 , the projections  166  are inserted into the corresponding notches  118 . This facilitates the alignment of the openings  158  and central passage  114 . Moreover, when the washer  150  is positioned on the connector  102 , the ribs  112  are captured in the slots  162 . The washer  150  may be placed on the connector  102  before or after the connector is secured to the truss T with the fasteners  18 . Once positioned, the rigid rod  14  can be inserted into and extend through the openings  158  and central passage  114 . The nut  16  is then threaded onto the end of the rigid rod  14  until the nut engages the washer  150 , thereby securing the girder tie  100  to the rigid rod. Preferably, the girder tie  100  is secured to the truss T before the nut  16  is tightened down against the washer  150 . 
     When the girder tie  100  is subject to the uplift forces, the first and second back flanges  108  are urged to move relative to one another (e.g., generally away from one another). Specifically, the first and second back flanges want to generally pivot and rotate relative to one another. This movement of the back flanges  108  is caused, at least in part, by the moment couple formed between the rigid rod connector  106  and the rigid rod  14  in conjunction with the force of the rigid rod being offset from the location of the resisting force provided by the fastener  18 . Below the point of level of the engagement of the nut  16  with the washer  150  at the top of the rigid rod connector  106 , the bottoms of the back flanges  108  are urged to pivot away from each other about a separation axis perpendicular to the back flanges and passing through the center of engagement of the nut with the washer at the top of the rigid rod connector. The back flange braces  160  inhibit this movement (e.g., lateral and/or rotational movement about the longitudinal axis of the rigid rod connector  106 ) of the back flanges  108 . As the back flanges  108  try to move away from one another due to the uplift forces, the bracing tabs  164  of the back flange braces  160  engage the ribs  112 , preventing the ribs and therefore the back flanges from moving apart and causing the back flanges  108  to act as a single piece of material. Moreover, because the back flange braces  160  restrict the movement (e.g., generally horizontal movement) of the back flanges  108 , any load (e.g., horizontal load) that would have been imposed on the fasteners  18  because of the movement of the back flanges is eliminated (e.g., all this horizontal load is contained and carried by the back flange braces). This eliminates placing any additional load on the fasteners  18  and generally keeps the load on the fasteners to generally only vertical shear and withdrawal. It is understood that by subjecting the fasteners  18  to less load (e.g., the horizontal load), the fasteners can carry or withstand a large amount of vertical shear load and withdrawal load. Thus, the back flange braces  160  help strengthen the connection of the building component connector  104  to the truss T. In addition, because the back flanges  108  pivot relative to another, a portion of the back flanges above the separation axis may move toward one another as the back flanges pivot. As a result, portions of the ribs  112  are brought into engagement with and push against one another, cancelling out a portion of the load (e.g., horizontal load). 
     The connector  102  and washer  150  are preferably made from metal. In one embodiment, the connector  102  and washer  150  are each formed as one piece (e.g., the connector and washer are each integral one-piece components) from metal blanks  200  and  300 , respectively, ( FIGS. 5 and 6 ) that are stamped from a sheet of material (e.g., metal) and bent into shape. As a result, the first and second back flanges  108  are indirectly connected to each other by way of the rigid rod connector  106 . However, there is no direct connection between the first and second back flanges in the plane of the first and second back flanges. A direct connection could be made between the first and second back flanges  108  in their common plane, but is not necessary because of the functionality of the washer  150 . In one embodiment, the connector  102  and washer  150  are each stamped from 10 gauge steel, although other suitable materials are within the scope of the present disclosure. In other embodiments, the connector  102  and the washer  150  are made from multiple pieces joined together, such as by welding. 
     Referring to  FIG. 7 , another embodiment of a girder tie according to the present disclosure is generally indicated by reference numeral  400 . Girder tie  400  is generally analogous to girder tie  100  and, thus, for ease of comprehension, where similar, analogous or identical parts are used, reference numerals “ 300 ” units higher are employed. Accordingly, unless clearly stated or indicated otherwise, the above descriptions regarding girder tie  100  also apply to girder tie  400 . 
     The girder tie  400  is a first or left oriented girder tie configured to be attached to the left side of a building component, such as a truss T′ or a column. In this embodiment, the right or second back flange  408  has a straight outer edge margin. As a result, the width of the right back flange  408  is reduced (compared to back flange  108 ), thereby reducing the overall width of the connector  402  (e.g., building component connector  404 ). The back flanges  408  of the girder tie  400  have different shapes. The straight edge of the second back flange  408  allows the connector  402  to be attached to smaller building elements, such as 2×4 piece of dimensioned lumber. 
     Referring to  FIGS. 8 and 9 , another embodiment of a girder tie according to the present disclosure is generally indicated by reference numeral  500 . Girder tie  500  is generally analogous to girder tie  100  and, thus, for ease of comprehension, where similar, analogous or identical parts are used, reference numerals “400” units higher are employed. Accordingly, unless clearly stated or indicated otherwise, the above descriptions regarding girder tie  100  also apply to girder tie  500 . 
     The girder tie  500  is a second or right oriented girder tie configured to be attached to the left side of a building component, such as a truss T′ or a column. In this embodiment, the left or first back flange  508  has a straight outer edge margin. As a result, the width of the left back flange  508  is reduced (compared to back flange  108 ), thereby reducing the overall width of the connector  502  (e.g., building component connector  504 ). This allows the connector  502  to be attached to smaller building elements, such as 2×4 piece of dimensioned lumber.  FIGS. 7 and 8  illustrate the left oriented girder tie  400  attached to the left side of the truss T′ and the right oriented girder tie  500  attached to the right side of the truss T′. 
     Modifications and variations of the disclosed embodiments are possible without departing from the scope of the invention defined in the appended claims. 
     When introducing elements of the present invention or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.