Patent Publication Number: US-11021865-B2

Title: Gusset plate connection of braced beam to column

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Ser. No. 14/729,995, filed Jun. 3, 2015, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to a moment resisting, beam-to-column joint connection structure, and more particularly to an all field-bolted dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure, and including an optional adjustable beam seat to facilitate alignment of bolt holes during erection of a moment resisting, beam-to-column joint connection structure. 
     BACKGROUND OF THE INVENTION 
     It has been found in a moment-resisting building having a structural steel framework, that most of the energy of an earthquake, or other extreme loading condition, is absorbed and dissipated, in or near the beam-to-column joints of the building. Braced structural connection systems including a brace-to-column and brace-to-beam joint connection must also be capable of withstanding loads generated during an earthquake, or other extreme loading condition. 
     In the structural steel construction of moment-resisting buildings, towers, and similar structures, most commonly in the past, the flanges of beams were welded to the face of columns by full-penetration, single bevel, groove welds. Thus, the joint connection was comprised of highly-restrained welds connecting a beam between successive columns. Vertical loads, that is, the weight of the floors and loads superimposed on the floors, were and still are assumed by many to be carried by vertical shear tabs or pairs of vertical, structural angle irons arranged back-to-back, bolted or welded to the web of the beam and bolted or welded to the face of the column. 
     The greater part of the vertical load placed upon a beam was commonly assumed to be carried by a shear tab bolted or welded to the web of the beam and bolted or welded to the face of the flange of the column at each end of the beam. Through the use of parallel face-to-face gusset plates welded to the column, the entire vertical load is carried by the gusset plates. 
     Experience has shown that the practice of welding the beam&#39;s flanges directly to the column flange using full penetration, single bevel groove welds is uncertain and/or unsuitable for resistance to earthquakes, explosions, tornadoes and other disastrous events, and must rely on highly experience welders which severely limits its application to being used in only certain regions of the world where pre-qualified welding capability is readily available and/or is the preferred construction means of that region or particular industry. Such connection means and welding practice has resulted in sudden, fractured welds, the pulling of divots from the face of the column flange, cracks in the column flange and column web, and various other failures. Such highly-restrained welds do not provide a reliable mechanism for dissipation of earthquake energy, or other large forces, and can lead to brittle fracture of the weld and the column, particularly the flange of the column and the web of the column in the locality of the beam-to-column joint, (known as the “panel zone”). 
     It is desirable to achieve greater strength, ductility and joint rotational capacity in beam-to-column connections in order to make buildings less vulnerable to disastrous events. Greater connection strength, ductility and joint rotational capacity are particularly desirable in resisting sizeable moments. That is, the beam-to-column moment-resisting connections in a steel frame building can be subjected to large rotational demands due to interstory lateral building drift. Engineering analysis, design and full-scale specimen testing have determined that prior steel frame connection techniques can be substantially improved by strengthening the beam-to-column connection in a way which better resists and withstands the sizeable beam-to-column, joint rotations which are placed upon the beam and the column. That is, the beam-to-column connection must be a strong and ductile, moment-resisting connection. 
     The parallel gusset plates may also be configured to receive diagonal braces. Thus, wherein the brace, column, and beam are connected by parallel gusset plates, the system is a “dual” system because it uses gusset plates to attach both beams and diagonal braces to columns, thereby combining, interactively, a structurally braced, highly ductile lateral load resisting connection system with a highly ductile structural moment resisting frame connection system to form a redundant structural lateral load resisting system. 
     Reference is made to co-assigned U.S. Pat. Nos. 5,660,017, 6,138,427, 6,516,583, and 8,205,408 (Houghton et al.) for further discussion of prior practice and the improvement of the structural connection between beams and columns through the use of gusset plates. These patents illustrate the improvements that have been manifested commercially in the construction industry by Houghton and others in side plate technology. Initially, side plate construction was introduced to greatly improve the quality of the beam-to-column connection. Further improvements included the provision of side plate technology using full length beams to achieve greater economy and to facilitate more conventional erection techniques. 
     SUMMARY 
     In one aspect, a joint connection structure of a building framework generally comprises a column assembly including a column and a pair of gusset plates connected to the column on opposite sides of the column and extending laterally outward from the column. A full-length beam assembly includes a full-length beam having upper and lower flanges and an end portion received between the gusset plates. The full-length beam is bolted to the gusset plates of the column assembly to connect the full-length beam assembly to the column assembly. A brace has an end portion received between the gusset plates and makes an angle with the beam and with the column. The brace is bolted to the gusset plates at the end portion of the brace. 
     In another aspect, a joint connection structure of a building framework generally comprises a column assembly including a column and a pair of gusset plates connected to the column on opposite sides of the column and extending laterally outward from the column. A full-length beam assembly includes a full-length beam having upper and lower flanges and an end portion received between the gusset plates. An adjustable beam seat is attached to the column and supports the full-length beam assembly at least partially between the gusset plates. The adjustable beam seat is configured to move the full-length beam assembly relative to the gusset plates prior to permanent attachment of the full-length beam assembly to the column assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a fragmentary perspective of a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a first embodiment; 
         FIG. 1A  is a diagrammatic elevation of a building framework; 
         FIG. 2  is a front view of the dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of  FIG. 1 ; 
         FIG. 3  is a section taken in the plane including line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a fragmentary perspective of a full-length beam assembly of the dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of  FIG. 1 ; 
         FIG. 5  is a front view of the full-length beam assembly in  FIG. 4 ; 
         FIG. 6  is a top view of the full-length beam assembly in  FIG. 4 ; 
         FIG. 7  is a section taken in the plane including line  7 - 7  of  FIG. 5 ; 
         FIG. 8  is a front view of a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a second embodiment with all bolts removed to show the openings they extend through; 
         FIG. 9  is a section taken in the plane including line  9 - 9  of  FIG. 8 , but illustrating the bolts removed from  FIG. 8 ; 
         FIG. 10  is a front view of a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a third embodiment with bolts connecting a gusset plate to the beam assembly and to a brace removed to illustrate the openings they would extend through; 
         FIG. 11  is a section taken in the plane including line  11 - 11  of  FIG. 10  with the bolts connecting the gusset plates to the beam assembly and the brace illustrated and bolts connecting angle irons to vertical shear plates removed to show openings through which they would extend; 
         FIG. 12  is a fragmentary front view of a full-length beam assembly of the dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure in  FIG. 10 ; 
         FIG. 13  is a section taken in the plane including line  13 - 13  of  FIG. 12  but with bolts removed; 
         FIG. 13A  is an enlarged fragmentary elevation of a portion of  FIG. 13 ; 
         FIG. 14  is an end view of the full-length beam assembly of  FIG. 12  but with bolts removed; 
         FIG. 15  is a section taken in the plane including line  15 - 15  of  FIG. 12 ; 
         FIG. 16  is a front view of a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a fourth embodiment with bolts connecting gusset plates to a beam assembly and a brace removed to show the openings through which they would extend; 
         FIG. 17  is a front view of a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a fifth embodiment with bolts removed to show openings through which they would extend; 
         FIG. 18  is a section taken in the plane including line  18 - 18  of  FIG. 17 ; 
         FIG. 19  is an enlarged fragmentary elevation of an adjustable beam seat in  FIG. 17 ; 
         FIG. 20  is a front view of a beam-to-column joint connection structure of a sixth embodiment; 
         FIG. 21  is a top view of the beam-to-column joint connection structure of  FIG. 20 ; 
         FIG. 21A  is a fragmentary perspective of a full-length beam assembly of the beam-to-column joint connection structure of  FIG. 20 ; 
         FIG. 22  is a front view of a beam-to-column joint connection structure of a seventh embodiment; 
         FIG. 23  is a top view of the beam-to-column joint connection structure of  FIG. 22 ; and 
         FIG. 24  is an enlarged fragmentary elevation of an adjustable beam seat in in  FIG. 22 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1-7 , an all field-bolted dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a first embodiment is generally indicated at  11 . The joint connection structure may be used in the construction of a building framework  1  (see  FIG. 1A ). In the illustrated embodiment, the joint connection structure joins a column assembly  13  including a column  15  to a full-length beam assembly  17  including a full-length beam  19 , and also a brace  20  to the column assembly. The brace  20  extends between the column  15  and beam  19  at an angle. A full-length beam is a beam that has a length sufficient to extend substantially the full-length between adjacent columns in a structure. Thus, a stub and link beam assembly as shown in FIGS. 5 and 16 of U.S. Pat. No. 6,138,427, herein incorporated by reference, is not a full-length beam. It is understood that the joint connection structure may include a beam-to-column type as shown, or a beam-to-column-to-beam type as shown in U.S. Pat. No. 8,146,322, herein incorporated by reference, depending upon the location of the joint connection structure within a building&#39;s framework. 
     The beam  19 , column  15 , and brace  20  may have any suitable configuration, such as an I-beam, H-beam configuration, or hollow rectangular shape (built up box member or HSS tube section). A spaced apart pair of parallel, vertically and horizontally extending gusset plates  21  sandwich the column  15 , beam  19 , and brace  20 . An extension  22  at an upper portion of the gusset plates  21  receives the brace  20 . Four optional horizontal shear plates  23  (only three are shown in  FIG. 1 ) are arranged in vertically spaced pairs generally aligned at top and bottom edges of the gusset plates  21 . Two angle irons (broadly, “connecting members”)  25 A are disposed on an upper flange of the beam  19  at an end of the beam (see,  FIG. 7 ). The angle irons  25 A are horizontally spaced from one another and extend along a length of an end portion of the beam  19 , and are located on opposite longitudinal edge margins of the beam. The angle irons  25 A connect the gusset plates  21  to the upper flange of the beam  19 . The angle irons  25 A are L-shaped in cross section. Each angle iron  25 A may include a horizontal first leg attached to the upper flange of the beam  19  and a vertical second leg projecting from the first leg perpendicular to the length of the beam. The first leg is attached in a suitable manner such as by a weld  29  between the toe of the first leg and the top surface of the upper flange of the beam  19  and by a weld  29  on the underside of the first leg to the tips of the upper flange. An outer surface of the second leg of each angle iron  25 A is bolted to an inner surface of a respective gusset plate  21  by horizontally spaced bolts  26  extending through aligned bolt holes  26 A in the second leg of the angle iron and respective gusset plate. Instead of two angle irons  25 A for example, a single channel welded to the top flange could be employed. 
     Flanges  27  of the brace  20  are bolted to the inner surface of a respective gusset plate  21  by diagonally spaced bolts  26  extending through aligned bolt holes  26 A in the flange of the brace and the respective gusset plate. In the illustrated embodiment, there are two rows of diagonally spaced bolt holes  26 A in each flange  27  located on opposite sides of a web of the brace  20  that receive the bolts  26  and connect the brace to the respective gusset plate. 
     Vertical shear plates  28  are welded at  29  to a web of the beam  19  and bolted to the gusset plates  21  by way of vertical angle irons  30  attached to the vertical shear plates ( FIG. 7 ). Each of the vertical angle irons  30  is attached in a suitable manner such as by welds  29  at the toe and heel of the leg of the vertical angle iron  30  abutting the vertical shear plate  28 . The vertical angle irons  30  are L-shaped in vertical plan view. Each vertical angle iron  30  may include a vertically extending first leg welded to a corresponding vertical shear plate  28  and a second vertically extending leg projecting perpendicular to the first leg along the length of the beam. An outer surface of the second leg of each angle iron  30  is bolted to an inner surface of a respective gusset plate  21  by vertically spaced bolts  26  extending through aligned bolt holes  26 A in the second leg of the angle iron  30  and respective gusset plate to connect the web of the beam  19  to the gusset plate. The vertical shear plates  28  and angle irons  30  are optional. 
     Two angle irons (broadly, “connecting members”)  25 B are disposed on a lower flange of the beam  19  at an end of the beam (see,  FIG. 7 ). The angle irons  25 B are horizontally spaced from one another, extend along a length of an end portion of the beam, and are located along opposite longitudinal edge margins of the beam  19 . The angle irons  25 B connect the gusset plates  21  to the lower flange of the beam  19 . The angle irons  25 B are L-shaped in cross section. Each angle iron  25 B may include a horizontal first leg attached to the lower flange of the beam  19  and a vertical second leg projecting from the first leg perpendicular to the length of the beam. The first leg is attached in a suitable manner to the bottom face of the lower flange of the beam  19  such as by a weld  29  between a toe of the first leg and the bottom surface of the lower flange of the beam  19  and a weld  29  between a top surface of the first leg and a tip of the lower flange. An outer surface of the second leg of each angle iron  25 B is bolted to an inner surface of a respective gusset plate  21  by horizontally spaced bolts  26  extending through aligned bolt holes  26 A in the second leg of the angle iron and respective gusset plate. Instead of two angle irons  25 B a single channel welded to the lower flange could be employed. Moreover, different combinations of connecting structure could be used. For example, one flange of the beam  19  might use two angle irons, while the other flange of the beam uses a channel. 
     The bolt holes  26 A in the gusset plates  21  may be larger than the bolt holes  26 A in the angle irons  25 A,  25 B,  30  to facilitate placement of one or more of the bolts  26  through slightly misaligned holes  26 A. In particular, the bolt holes  26 A in the angle irons  25 A,  25 B could be standard size and the bolt holes  26 A in the gusset plates  21  associated with the bolt holes in the angle irons  25 A,  25 B could be vertically slotted (as shown) such that a first dimension of the bolt holes that extends generally parallel to a longitudinal axis of the column  15  is greater than a second dimension of the bolt holes that extends generally perpendicular to the longitudinal axis of the column. The bolts  26  are inserted first through the standard sized holes in the angle irons  25 A,  25 B and then into the associated slotted bolt holes  26 A of the gusset plates  21 . Similarly, the bolt holes  26 A in the angle irons  30  could be standard size and the bolt holes  26 A in the gusset plates  21  associated with the bolt holes in the angle irons  30  could be horizontally slotted (as shown) such that a first dimension of the bolt holes that extends generally parallel to a longitudinal axis of the beam  19  is greater than a second dimension of the bolt holes that extends generally perpendicular to the longitudinal axis of the beam. The bolts  26  are inserted first through the standard sized holes in the angle irons  30  and then into the associated slotted bolt holes  26 A of the gusset plates  21 . The bolt holes  26 A in the gusset plates  21  associated with the bolt holes in the brace  20  may have a different configuration than the bolt holes in the brace. In particular, the bolt holes  26 A in the brace could be standard size and the bolt holes  26 A in the gusset plates  21  associated with the bolt holes in the brace could be diagonally slotted (as shown) such that a first dimension of the bolt holes that extends generally perpendicular to a longitudinal axis of the brace  20  is greater than a second dimension of the bolt holes that extends generally parallel to the longitudinal axis of the brace. The bolts  26  are inserted first through the standard sized holes in the brace  20  and then into associated bolt holes  26 A in the gusset plates  21 . It will be appreciated that similar slotting of one of two mating holes may be used to facilitate bolting the components together in all the disclosed embodiments. Moreover, the holes  26 A in the angle irons  25 A,  25 B may be slotted and the holes  26 A in the gusset plates  21  may be standard within the scope of the present invention. Similarly, the bolt holes in the brace  20  may be slotted and the holes  26 A in the gusset plates  21  may be standard. The bolt connection structure of this invention allows workers in the field to draw the gusset plates  21  into flush engagement with the angle irons  25 A,  25 B,  30  even with an initial gap between the gusset plates and full-length beam assembly  17 , without the need of an external clamping structure. 
     Referring to  FIGS. 4-7 , the full-length beam assembly  17  may be fabricated at a fabrication shop prior to being transported to the construction site. To fabricate the full-length beam assembly  17 , the angle irons  25 A,  25 B are welded at  29  or otherwise attached to the upper and lower flanges of the beam  19 . Additionally, the vertical shear plates  28  and angle irons  30  are welded or otherwise attached to the web of the beam  19 . Any welds on the beam assembly needed to form the joint connection structure can be made at the shop so no welding is required at the work site. The angle irons  25 A,  25 B, and  30  may have other configurations than those illustrated in the current embodiment. 
     Referring to  FIGS. 1-3 , the column assembly  13  may also be fabricated at a fabrication shop and later transported to the construction site. To fabricate the column assembly  13 , the gusset plates  21  are welded at  29  to optional horizontal shear plates  23 , and also welded to the flanges of column  15  along longitudinal edge margins of the column. The optional horizontal shear plates  23  are welded at  29  or otherwise attached to the web of the column and to the top and bottom edges of the gusset plates. Any welds on the column assembly  13  needed to form the braced beam-to-column moment-resisting joint may be carried out at the shop. The horizontal shear plates  23  can be omitted from the column assembly  13 . The gusset plates  21  can have other configurations than those illustrated in the current embodiment. 
     At the construction site, the column assembly  13  is joined to the full-length beam assembly  17  and the brace  20  is joined to the column assembly and full-length beam assembly. The column assembly  13  is first erected in a vertical orientation and the end of the full-length beam assembly  17  is positioned horizontally and adjacent to the column assembly, over the gusset plates  21 . The full-length beam assembly  17  is then lowered between the gusset plates  21  so that the gusset plates are disposed on opposite sides of the beam  19  and angle irons  25 A,  25 B of the full-length beam assembly  17 . To fixedly secure the two assemblies  13 ,  17 , horizontally spaced bolts  26  are used to attach the gusset plates  21  to the angle irons  25 A,  25 B through aligned bolt holes in the respective components. Vertically spaced bolts  26  are used to attach the gusset plates  21  to the angles irons  30  welded to the web of the beam  19 . The brace  20  is then lowered between the extensions  22  of the gusset plates  21  so that the extensions are disposed on opposite sides of the brace. Diagonally spaced bolts  26  are used to attach the gusset plates  21  to the brace  20 . Thus, at the construction site, the dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure  11  is completed exclusively through bolt connections. In the field, the dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure  11  is constructed without the use of welds. The joint connection structure  11  can be used if the building frame is dimensionally close to the exterior curtain wall of the building because the angle irons  25 A,  25 B are on the inside of the gusset plates  21 . 
     The joint connection structure  11  outlined above is a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure. It will be understood by a person having ordinary skill in the art that a braced beam-to-column-to-beam type structure may have additional analogous components. Most preferably, each of the components of the joint connection structure  11 , as well as the beam  19 , column  15 , and brace  20 , are made of structural steel. Some of the components of the joint connection structure  11  are united by welding and some by bolting. The welding may be initially performed at a fabrication shop. The bolting may be performed at the construction site, which is the preferred option in many regions of the world. 
     The bolted joint connection structure of the present invention also increases construction tolerance for misalignment of components during field steel frame erection because of the novel slotting orientation of the bolt holes  26 A in which some are elongated in a vertical direction and others are elongated in a horizontal direction that is transverse to the longitudinal axis of the beam  19 . 
     Unlike oversized holes requiring the use of slip-critical bolts, the slotted bolt holes  26 A are larger than standard bolt holes in only one direction. Also, the slot direction of the bolt holes  26 A associated with angle irons  25 A,  25 B is perpendicular to the direction of load, that is, does not extend along the longitudinal axis of the beam  19 . Instead, the slots of the bolt holes  26 A associated with the angle irons  25 A,  26 B extend perpendicular (broadly, “transverse”) to the longitudinal axis of the beam  19  so that when the joint connection structure  11  is loaded, and in particular when the beam is loaded axially along its length or about its major axis in bending, a gap is not formed between the bolts  26  and their respective bolt holes  26 A (i.e., no slip of bolt occurs because bolts  26  are already loaded by direct bearing in shear). As used herein “transverse” to the longitudinal axis of the beam  19  means any direction that crosses over the longitudinal axis of the beam and is not parallel to the longitudinal axis of the beam. In some embodiments, the bolt holes  26 A have a slotted dimension that is up to about 2.5 times the diameter of the bolt  26 . In some embodiments, the bolt holes  26 A have a slotted dimension that is from about 3/16 in. up to about 2¾ in. larger than the diameter of the bolt  26 . In a preferred embodiment, the bolt holes  26 A have a slotted dimension that is about ¾ in. larger than the diameter of the bolt  26 . 
     The unique geometry and stiffness of this all shop fillet-welded and all field-bolted dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure  11  maximizes its performance and the broadness of its design applications, including both extreme wind and moderate-to-severe seismic conditions. In particular, the all field-bolted joint connection structure  11  preserves the physical separation (or gap) between the end of a full-length beam  19  and the flange face of the column  15  made possible by the use of vertically and horizontally extended parallel gusset plates  21  that sandwich the column and the beam similar to prior designs which feature an all field fillet-welded joint connection structure; thus eliminating all of the uncertainty of bending moment load transfer between a rigidly attached steel moment frame beam and column used in the past. 
     Further, by including the vertically and horizontally extending parallel gusset plates  21  that sandwich both the column  15 , beam  19 , and brace  20 , this current all field-bolted dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure  11  preserves the advantage of increased beam-to-column joint stiffness, with a corresponding increase in overall steel moment frame stiffness. The dual system joint connection structure  11  combines a brace frame connection system and a beam frame connection system. The brace frame connection system and the beam frame connection system share the applied lateral load on the basis of relative system stiffnesses. This dual system stiffness joint connection structure  11  can result in smaller beam and brace sizes when the building design is controlled by lateral story drift (not member strength), and hence reduced material costs. The joint connection structure  11  results in reduced load demand on the braced frame lateral load resisting system, with corresponding smaller beam and brace sizes. When the building design is controlled by member strength (not lateral story drift), this all field-bolted dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure  11  also permits reducing the beam size and column size, and hence material quantities and fabrication cost, at least in part because its connection geometry has no net section reduction in either the beam or the column (i.e., no bolt holes through either the beam or column), thereby maintaining the full strength of the beam and column. 
     In one aspect of the present disclosure, a full-length beam is connected to gusset plates by bolts so that the full-length beam and gusset plates are substantially free of welded connection. Additionally, a brace is connected to the gusset plates by bolts so that the brace and gusset plates are substantially free of welded connection. It will be understood that welding the column assembly  13  to the full-length beam assembly  17  and/or brace  20  is within the scope of that aspect of the disclosure. 
     Referring to  FIGS. 8 and 9 , a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a second embodiment is generally indicated at  111 . In the illustrated embodiment, the joint connection joins a column assembly  113  including a column  115  to a full-length beam assembly  117  including a full-length beam  119 , and a brace  120  to the column assembly. The joint connection structure  111  of the second embodiment is substantially identical to the joint connection structure  11  of the first embodiment. The only differences between the two embodiments is gusset plates  121  have two rows of horizontally spaced bolt holes  126 A associated with angle iron  125 A, and two rows of horizontally spaced bolt holes  126 A associated with angle iron  1258  for receiving bolts  126  to connect the gusset plates  121  to the beam assembly  117 . It will be understood that vertical second legs of the angle irons  125 A,  1258  may have a larger vertical dimension to accommodate for the two rows of bolt holes  126 A. The bolt holes  126 A in both rows may be slotted as described for bolt holes  26 A. 
     Referring to  FIGS. 10-15 , a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a third embodiment is generally indicated at  211 . In the illustrated embodiment, the joint connection joins a column assembly  213  including a column  215  to a full-length beam assembly  217  including a full-length beam  219 , and a brace  220  to the column assembly. The joint connection structure  211  of the third embodiment is substantially identical to the joint connection structure  11  of the first embodiment. The only difference between the two embodiments is that vertical angle iron  230  is bolted to vertical shear plate  228  ( FIG. 11 ). The vertical angle irons  230  are L-shaped in vertical plan view. Each vertical angle iron  230  may include a vertically extending first leg bolted to a corresponding vertical shear plate  228  by vertically spaced bolts  226  extending through aligned bolt holes  226 A in the first leg of the angle iron  230  and respective vertical shear plate  228  to connect the angle iron to the vertical shear plate. The bolt holes  226 A in the first leg of the angle iron  230  may be slotted in a vertical direction and the bolt holes  226 A in the vertical shear plate  228  may be slotted in a horizontal direction ( FIG. 13A ). The horizontal slotting of the bolt holes  226 A in the vertical shear plate  228  and the vertical slotting of the holes  226 A in the angle iron  230  allow the position of the angle iron  230  to be adjusted to a final position. Once the final position is achieved, a weld  229  secures the angle iron  230  in place relative to the vertical shear plate  228  and the beam  219  ( FIG. 14 ). The bolts  226  extending through the slotted holes  226 A in the vertical shear plate  228  and the angle iron  230  remain in place after the weld  229  for cooperating with the weld to fix the angle iron with respect to the vertical shear plate and beam  219 . A second vertically extending leg projects perpendicular to the first leg along the length of the beam  219 . An outer surface of the second leg of each angle iron  230  is bolted to an inner surface of a respective gusset plate  221  by vertically spaced bolts  226  extending through aligned bolt holes  226 A in the second leg of the angle iron  30  and respective gusset plate to connect the web of the beam  219  to the gusset plate. 
     Referring to  FIGS. 1A and 16 , a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a fourth embodiment is generally indicated at  311 . In the illustrated embodiment, the joint connection joins a column assembly  313  including a column  315  to a full-length beam assembly  317  including a full-length beam  319 , and upper and lower braces  320 A,  320 B to the column assembly. The joint connection structure  311  of the fourth embodiment is substantially identical to the joint connection structure  11  of the first embodiment. The only differences between the two embodiments is gusset plates  321  have upper and lower extensions  322  for receiving the upper and lower braces  320 A,  320 B. It is to be understood that the gusset plates can be configured to receive more than two braces between them. For example with reference to  FIG. 1A , it may be seen that at one location (designated  11 ′), four braces are received between two gusset plates attached to one of the columns  15  and projecting to both sides of the column. Although not illustrated, in that situation the gusset plate may have four extensions, one for each of the four braces. 
     Referring to  FIGS. 17-19 , a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure of a fifth embodiment is generally indicated at  411 . In the illustrated embodiment, the joint connection joins a column assembly  413  including a column  415  to a full-length beam assembly  417  including a full-length beam  419 , and a brace  420  to the column assembly. The joint connection structure  411  of the fifth embodiment is similar to the joint connection structure  11  of the first embodiment. The difference between the two embodiments is that the vertical shear plate  28  and vertical angle iron  30 , and associated bolt holes in the gusset plates, of the first embodiment are removed. Additionally, an adjustable beam seat  440  is attached to the column  415  in the fifth embodiment for temporarily supporting the full-length beam assembly  417  before being bolted to the column assembly  413 . The adjustable beam seat  440  comprises an angle iron  442 . The angle iron  442  may include a vertical first leg attached to a flange of the column  415  and a horizontal second leg projecting from the first leg away from the column perpendicular to a length of the column. The first leg is attached to the column  415  in a suitable manner such as by a weld  429  ( FIG. 19 ). A reinforcement plate  444  is disposed generally at a middle of the angle iron  442  and defines a web connecting the first and second legs. The reinforcement plate  444  provides additional structural rigidity to the angle iron  442  so that the angle iron is able to support the weight of the full-length beam assembly  417 . It will be understood that the reinforcement plate  444  may be omitted within the scope of the present invention. 
     A pair of threaded studs  446  extend through respective holes in the second leg of the angle iron  442 . Each stud  446  is attached in the respective hole by a pair of nuts  448  threaded on the stud above and below the second leg of the angle iron  442 . The top ends of the threaded studs  446  engage a bottom surface of a lower flange of the beam  419  to temporarily support the full-length beam assembly  417  before the full-length beam assembly is bolted to the column assembly  413 . In the illustrated embodiment, the top end of each stud  446  is attached by weld  447  to the bottom surface of the lower flange of the beam  419 . Typically, the threaded studs  446  are welded to the lower flange of the beam  419  in the shop during fabrication of the beam assembly. However, a stud or bolt (not shown) could be separate from the beam  419  (i.e., not welded to the beam) and selectively engageable with the beam. 
     The adjustable beam seat  440  is attached to the column  415 , such that a top surface of a second leg of angle iron  442  is generally below a final design height of the lower flange of the beam  419  after the full-length beam assembly  417  is bolted to the column assembly. The nuts  448  can be selectively turned to move studs  446  and hence the full-length beam assembly  417  to the final beam height. In order to provide physical clearance between the angle iron  442  attached to column  413  and angle irons  425 B, as well as to provide adequate worker access for adjusting the leveling nuts  448  of threaded studs  446  to raise or lower the full-length beam assembly  417  for fine tuning the alignment of bolt holes between gusset plates  421  and angle irons  425 A,  425 B during erection, the ends of angle irons  425 B nearest the face of column  415  are located increased distances away from face of column  415  as compared to its location shown in  FIG. 2 . For reasons of design symmetry, angle irons  425 A are located the same increased distance way from face of column  415 . 
     In use, the full-length beam assembly  417  can be lowered down between the gusset plates  421  and engaged with the adjustable beam seat  440 . The threaded studs  446  are received into respective holes in the angle iron  442  as the beam assembly  417  is lowered between the gusset plates until the upper nuts  448  engage the horizontal second legs of the beam seat  440 . The lower nuts  448  are then threaded onto the lower ends of the threaded studs  446 . To adjust the height of the full-length beam assembly  417  while being supported by the adjustable beam seat  440 , the nuts  448  are rotated causing the beam assembly to either be raised when the nuts are rotated in a first direction or lowered when the nuts are rotated in a second direction opposite the first direction. Typically, this is done to achieve alignment of bolt holes in the gusset plates with bolt holes associated with the beam assembly  417  and/or brace  420 . Once the full-length beam assembly  417  is in the selected position, the beam assembly can be bolted to the column assembly  413 . Therefore, the adjustable beam seat  440  both supports the weight of the full-length beam assembly  417  and facilitates a fine tune adjustment of the height of the beam assembly for locating the beam assembly in a position for being bolted to the column assembly  413 . The beam seat  440  allows the beam assembly  417  to be stabilized prior to any fixed connection to the column assembly  413 . 
     Referring to  FIGS. 20-21A , a beam-to-column moment-resisting joint connection structure of a sixth embodiment is generally indicated at  511 . In the illustrated embodiment, the joint connection joins a column assembly  513  including a column  515  to a full-length beam assembly  517  including a full-length beam  519 . The joint connection structure  511  of the sixth embodiment is similar to the joint connection structure  11  of the first embodiment. The differences between the two embodiments is that the first embodiment is a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure which includes a brace  20  and modified gusset plates  21  for receiving an end portion of the brace. The joint connection structure  511  of the sixth embodiment is not a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure and thus omits the brace and incorporates rectangular gusset plates  521 . However, as disclosed in the first embodiment, vertical shear plates  528  are welded at  529  to a web of the beam  519  and bolted to the gusset plates  521  by way of vertical angle irons  530  attached to the vertical shear plates. 
     Referring to  FIGS. 22-24 , a beam-to-column moment-resisting joint connection structure of a seventh embodiment is generally indicated at  611 . In the illustrated embodiment, the joint connection joins a column assembly  613  including a column  615  to a full-length beam assembly  617  including a full-length beam  619 . The joint connection structure  611  of the seventh embodiment is similar to the joint connection structure  411  of the fifth embodiment. The differences between the two embodiments is that the fifth embodiment is a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure and includes a brace  420  and modified gusset plates  421  for receiving an end portion of the brace. The joint connection structure  611  of the seventh embodiment is not a dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structure and thus omits the brace and incorporates rectangular gusset plates  621 . 
     It will be understood that the specific connections described in each of the embodiments are interchangeable. 
     When introducing elements of the present invention or the preferred embodiments(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. 
     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 
     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. 
     Moment resisting column-to-beam joint connection structures, column assemblies and beam assemblies that are constructed according to the principles of the present invention provide numerous unique features, benefits and advantages. Reference is made to the figures illustrating one of the embodiments to which the advantages and benefits apply. All field-bolted dual braced/moment resisting frame, beam-to-column-to-diagonal brace joint connection structures, column assemblies, and full-length beam assemblies that are constructed according to the principles of the present invention provide numerous unique features and advantages. At least one embodiment has the advantage of reducing material quantities and associated cost. In at least one embodiment, the present invention provides ease and predictability of fabrication. At least one other embodiment may have the advantage of faster frame erection due to purposeful mitigation of erection alignment and milled, rolled section tolerance uncertainties. Still in other embodiments the present invention may provide maximum steel frame stiffness for controlling lateral drift of the structural frame system. In at least one embodiment, the present invention provides overall optimum performance when subjected to severe load application and system ductility demand on the joint connection structure.