US20160356033A1

US20160356033A1 - Gusset plate connection of braced beam to column

Info

Publication number: US20160356033A1
Application number: US14/729,995
Authority: US
Inventors: David L. Houghton; Behzad Rafezy; Jared J Adams
Original assignee: Mitek Holdings Inc
Current assignee: Mitek Holdings Inc
Priority date: 2015-06-03
Filing date: 2015-06-03
Publication date: 2016-12-08
Also published as: WO2016193911A1; US11021865B2; GB201717740D0; GB2554261B; US20190106875A1; GB2554261A

Abstract

A joint connection structure of a building framework includes 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.

Description

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'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'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”) 25A are disposed on an upper flange of the beam 19 at an end of the beam (see, FIG. 7). The angle irons 25A 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 25A connect the gusset plates 21 to the upper flange of the beam 19. The angle irons 25A are L-shaped in cross section. Each angle iron 25A 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 25A is bolted to an inner surface of a respective gusset plate 21 by horizontally spaced bolts 26 extending through aligned bolt holes 26A in the second leg of the angle iron and respective gusset plate. Instead of two angle irons 25A 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 26A in the flange of the brace and the respective gusset plate. In the illustrated embodiment, there are two rows of diagonally spaced bolt holes 26A 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 26A 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”) 25B are disposed on a lower flange of the beam 19 at an end of the beam (see, FIG. 7). The angle irons 25B 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 25B connect the gusset plates 21 to the lower flange of the beam 19. The angle irons 25B are L-shaped in cross section. Each angle iron 25B 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 25B is bolted to an inner surface of a respective gusset plate 21 by horizontally spaced bolts 26 extending through aligned bolt holes 26A in the second leg of the angle iron and respective gusset plate. Instead of two angle irons 25B 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 26A in the gusset plates 21 may be larger than the bolt holes 26A in the angle irons 25A, 25B, 30 to facilitate placement of one or more of the bolts 26 through slightly misaligned holes 26A. In particular, the bolt holes 26A in the angle irons 25A, 25B could be standard size and the bolt holes 26A in the gusset plates 21 associated with the bolt holes in the angle irons 25A, 25B 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 25A, 25B and then into the associated slotted bolt holes 26A of the gusset plates 21. Similarly, the bolt holes 26A in the angle irons 30 could be standard size and the bolt holes 26A 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 26A of the gusset plates 21. The bolt holes 26A 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 26A in the brace could be standard size and the bolt holes 26A 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 26A 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 26A in the angle irons 25A, 25B may be slotted and the holes 26A 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 26A 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 25A, 25B, 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 25A, 25B 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 25A, 25B, 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 25A, 25B 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 25A, 25B 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 25A, 25B 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 26A 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 26A are larger than standard bolt holes in only one direction. Also, the slot direction of the bolt holes 26A associated with angle irons 25A, 25B 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 26A associated with the angle irons 25A, 26B 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 26A (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 26A have a slotted dimension that is up to about 2.5 times the diameter of the bolt 26. In some embodiments, the bolt holes 26A 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 26A 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 126A associated with angle iron 125A, and two rows of horizontally spaced bolt holes 126A associated with angle iron 125B 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 125A, 125B may have a larger vertical dimension to accommodate for the two rows of bolt holes 126A. The bolt holes 126A in both rows may be slotted as described for bolt holes 26A.
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 226A 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 226A in the first leg of the angle iron 230 may be slotted in a vertical direction and the bolt holes 226A in the vertical shear plate 228 may be slotted in a horizontal direction (FIG. 13A). The horizontal slotting of the bolt holes 226A in the vertical shear plate 228 and the vertical slotting of the holes 226A 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 226A 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 226A 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 320A, 320B 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 320A, 320B. 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 425B, 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 425A, 425B during erection, the ends of angle irons 425B 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 425A 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.

Claims

1. A joint connection structure of a building framework comprising:

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 including a full-length beam having upper and lower flanges and an end portion received between the gusset plates, the full-length beam being bolted to the gusset plates of the column assembly to connect the full-length beam assembly to the column assembly; and

a brace having an end portion received between the gusset plates, the brace making an angle with the beam and with the column, the brace being bolted to the gusset plates at the end portion of the brace.

2. The joint connection structure of claim 1 further comprising slotted bolt holes in one of the gusset plates and the brace for receiving bolts to connect the gusset plates to the brace.

3. The joint connection structure of claim 2 wherein the slotted bolt holes are slotted in a direction generally perpendicular to a longitudinal axis of the brace.

4. The joint connection structure of claim 3 wherein the slotted bolt holes are in at least one of the gusset plates.

5. The joint connection structure of claim 1 wherein the beam comprises a web connecting the upper and lower flanges of the beam, the joint connection structure further comprising a vertical shear plate attached to the web of beam, the vertical shear plate being bolted to one of the gusset plates.

6. The joint connection structure of claim 5 further comprising slotted bolt holes in one of said one of the gusset plates and the vertical shear plate for receiving bolts to connect the vertical shear plate to said one of the gusset plates.

7. The joint connection structure of claim 6 wherein the slotted bolt holes are slotted in a direction generally parallel to a longitudinal axis of the beam.

8. The joint connection structure of claim 5 wherein the vertical shear plate comprises a plate portion attached to the beam web and an angle iron attached to the plate portion and bolted to one of the gusset plates.

9. The joint connection structure of claim 8 further comprising slotted bolt holes in one of the angle iron and the plate portion of the vertical shear plate receiving bolts connecting the angle iron to the plate portion.

10. The joint connection structure of claim 9 wherein the slotted bolt holes are slotted in a direction generally perpendicular to a longitudinal axis of the beam.

11. The joint connection structure of claim 9 wherein the slotted holes are in both the plate portion of the vertical shear plate and in the angle iron of the vertical shear plate, the slotted holes in the plate portion being slotted in a direction orthogonal to the slotted holes in the angle iron.

12. The joint connection structure of claim 1 further comprising slotted bolt holes in at least one of the gusset plates.

13. The joint connection structure of claim 12 wherein the slotted bolt holes are slotted in a direction generally parallel to a longitudinal axis of the beam.

14. The joint connection structure of claim 12 wherein the slotted bolt holes are arranged in rows near at least one of a top and bottom edge of said at least one of the gusset plates.

15. The joint connection structure of claim 1 further comprising an adjustable beam seat attached to the column and supporting the full-length beam assembly at least partially between the gusset plates, the beam seat being configured to move the full-length beam assembly relative to the gusset plates prior to bolting the full-length beam assembly to the column assembly.

16. The joint connection structure of claim 1 wherein the full-length beam assembly comprises angle irons attached to the upper flange and angle irons attached to the lower flange, the angle irons being bolted to the gusset plates.

17. A joint connection structure of a building framework comprising:

a full-length beam assembly including a full-length beam having upper and lower flanges and an end portion received between the gusset plates; and

an adjustable beam seat attached to the column and supporting the full-length beam assembly at least partially between the gusset plates, the adjustable beam seat comprising a first portion fixed to the column assembly and a second portion movably attached to the first portion, the second portion does not extend through a hole in the beam assembly or the column assembly for permanent attachment of the full-length beam assembly to the column assembly, the adjustable beam seat being configured to move the full-length beam assembly relative to the gusset plates by movement of the second portion relative to the first portion.

18. The joint connection structure of claim 17 wherein the first portion comprises an angle iron attached to the column and the second portion comprises a stud assembly attached to the angle iron and engaging the full-length beam to adjust a position of the full-length beam assembly.

19. The joint connection structure of claim 18 further comprising a hole in the angle iron, the stud assembly comprising a threaded stud extending through the hole and operatively engaging the full length beam assembly, and at least one nut receiving the threaded stud to secure the threaded stud in the hole, rotation of the nut causing the threaded stud to move relative to the angle iron to adjust the position of the full-length beam assembly.

20. The joint connection structure of claim 19 wherein the angle iron includes a first leg welded to the column and a second leg projecting transversely from the first leg and laterally away from the column, the hole being disposed in the second leg.

21. The joint connection structure of claim 19 wherein the top end of the threaded stud is welded to the lower flange of the full-length beam.

22. The joint connection structure of claim 17 wherein the second portion is configured to engage a bottom of the beam assembly to move the beam assembly relative to the gusset plates.