FIELD
The present disclosure is directed to bolted beam to column connections in buildings, particularly where one or both of the beam and column are box or hollow structures.
BACKGROUND
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.
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 face-to-face side plates welded to the column, the greater part of the vertical load is carried by the side plates.
Side plate connections require parallel juxtaposed reinforcing plates that extend across the column depth. For HSS (hollow structural section) columns and beams, there are restrictions for bolting the side plates to the column/beam depending on the length, size, and location of the side plates. Some conventional methods involve the use of ‘blind’ bolts which include a steel pin, collar, and sleeve. The blind bolts are inserted through pre-drilled holes and the pressure on the collar creates a solid connection as an expander deforms to hold the blind side firm while the collar creates a seal on the side where the tool is applied. Conventional methods also use welded threaded studs on the side of the of the HSS section. However, there are many fabrication tolerance issues related with these methods. The present disclosure provides structure that allows for typical fabrication accesses in the placement and usage of standard bolting techniques for connecting side plates to columns and beams.
SUMMARY
In one aspect, a joint connection structure of a building framework generally comprises a column assembly including a column and a pair of side plates attached to the column on opposite sides of the column and extending laterally outward from the column. A beam assembly includes a beam having an end portion proximate the side plates. At least one of the column and the beam has an opening in an area between the side plates to provide access for bolting at least one of the side plates to one of the column and the beam. The opening is free of a fastener extending through the opening when the column assembly is attached to the beam assembly.
In another aspect, a column assembly generally comprises a column and a pair of side plates bolted to the column on opposite sides of the column and extending laterally outward from the column. The column defines an opening disposed between the side plates providing access to an interior of the column for bolting the side plates to the column. The opening is free of a fastener for attaching one of the side plates to the column.
In yet another aspect, a beam for attachment to a column assembly generally comprises a beam including a top surface, a bottom surface, and a pair of side surfaces extending between the top and bottom surfaces. A plurality of bolt holes are in each of the side surfaces for receiving bolts to attach side plates of the column assembly to the beam. An opening is disposed in one of the top surface and bottom surface. The opening is free of a fastener when the side plates are attached to the beam.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a beam-to-column-to-beam joint connection structure of the present disclosure;
FIG. 2 is a right side view of the beam-to-column-to-beam joint connection structure of FIG. 1;
FIG. 3 is a top view of the beam-to-column-to-beam joint connection structure of FIG. 1;
FIG. 4 is a front view of a column assembly of the beam-to-column-to-beam joint connection structure of FIG. 1;
FIG. 5 is a right side view of the column assembly of FIG. 4;
FIG. 6 is a left side view of the column assembly of FIG. 4;
FIG. 7 is a perspective of a column of the column assembly of FIG. 4;
FIG. 7A is a front view of the column assembly of the beam-to-column-to-beam joint connection structure of FIG. 1 showing an alternative opening configuration;
FIG. 8 is a fragmentary perspective of a beam on the right side of the beam-to-column-to-beam joint connection structure of FIG. 1;
FIG. 9 is an end view of the beam of FIG. 8;
FIG. 10 is a top view of the beam similar to the beam of FIG. 8;
FIG. 11 is a front view of the beam of FIG. 10;
FIG. 11A is a front view of the beam of FIG. 10 showing an alternative opening configuration;
FIG. 12 is a front view of a beam assembly on the left side of the beam-to column-to-beam joint connection structure of FIG. 1;
FIG. 13 is a top view of the beam assembly of FIG. 12;
FIG. 14 is an end view of the beam assembly of FIG. 12;
FIG. 15 is a perspective of another embodiment of a column assembly;
FIG. 16 is a perspective of another embodiment of a beam-to-column joint connection structure;
FIG. 17 is a top view of the beam-to-column joint connection structure of FIG. 16; and
FIG. 18 is a side view of the beam-to-column joint connection structure of FIG. 16.
Corresponding reference characters indicate corresponding parts throughout the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1-3, a beam-to-column-to-beam moment-resisting joint connection structure of the present disclosure is shown generally at 11. The joint connection structure may be used in the construction of a building framework. In the illustrated embodiment, the joint connection joins a column assembly 13 including a column 15 to full-length beams 19 and 20 extending laterally outward from the column 15 in opposite directions and generally along a common longitudinal axis. A full-length beam is a beam that has a length sufficient to extend substantially the full length between adjacent columns in a structure. It will be understood that the joint connection structure may include a single column and a single beam, or additional beams and columns suitably connected without departing from the scope of the disclosure. Beams that extend less that the full length between adjacent columns may also be used within the scope of the present invention.
In the illustrated embodiment, the column 15 is an HSS (hollow structural support) column, beam 19 is a HSS beam, and beam 20 is an I-beam. However, the column 15 and beams 19, 20 could have other configurations without departing from the scope of the disclosure. A spaced apart pair of parallel, vertically and horizontally extending side plates 21 sandwich the column 15 and beams 19, 20. The side plates 21 have a length L (FIG. 3) extending horizontally across the side plates, and a height H (FIG. 2) extending vertically along the side plates. The side plates 21 are bolted to column 15 and to the beams 19, 20 using bolts 26. As will be explained in greater detail below, the construction of the column 15 is configured to provide access to fabricators for bolting the side plates 21 to the column and the beams 19, 20. Additionally, the construction of the HSS beam 19 is also configured to provide access for bolting the side plates to the HSS beam. To this effect, standard bolts 26 may be used to bolt the side plates 21 to the column 15 and to the beams 19, 20.
Referring to FIGS. 4-7, the column 15 comprises a hollow column having open longitudinal end. The column 15 could also have a closed end without departing from the scope of the disclosure. In the illustrated embodiment, the column 15 has a rectangular cross sectional shape defined by four side walls extending along a length of the column. A first pair of opposing side walls 31 extend across a major (i.e., larger) dimension of the column 15. The first pair of side walls 31 are configured for engagement with respective side plates 21 when the side plates are bolted to the column 15. In one embodiment, the side plates 21 extend along substantially an entire width of the first side walls 31. A second pair of opposing side walls 33 extend between the first pair of side walls 31 and define the smaller lateral dimension of the column 15. The second pair of side walls 33 are positioned to oppose ends of respective beams 19, 20 when the beams are bolted to the column assembly 13. It will be understood that the column 15 could have a square cross-sectional shape such that the first side walls 31 and second side walls 33 have the same lateral dimension. Additionally, the second side walls 33 could have a larger lateral dimension that the first side walls 31.
Referring back to FIGS. 1-3, the side plates 21 reinforce the column 15 and beams 19, 20, and reduce the stresses normally found across the second pair of side walls 33 when the column and beams are attached in other ways such as by directly welding or bolting the beams to the beam facing surfaces (i.e., side walls 33) of the column. In particular, the side plates 21 cause the stresses on the joint connection to be transferred to the sides of the joint along the side plates 21 away from the beam facing surfaces 33 of the column 15. Thus, the areas of the side walls 33 the column 15 between the side plates 21 constitute areas of relatively low stress within the joint connection.
Referring to FIGS. 2 and 5-7, at least one of the second pair of side walls 33 includes an opening 35. In the illustrated embodiment, openings 35 are formed in both of the second pair of side walls 33. However, only one of the side walls 33 may have an opening 35. The openings 35 have a generally rectangular shape with rounded corners. The openings 35 extend along the length of the column 15 such that a longitudinal axis of the openings extends generally parallel to the length of the column. However, the openings 35 could have other shapes and orientations without departing from the scope of the disclosure. For example, the openings 35 may have square corners or may be square shaped or the opening may be circular in shape. Additionally, the openings 35 may extend in other directions along the surface of the side walls 33. Bolt holes 26A (FIG. 7) in the first side walls 31 provide holes to receive the bolts 26 for attaching the side plates 21 to the column 15. The openings 35 in the side walls 33 are disposed between a top and bottom perimeter boundary of the bolt holes 26A in the column 15. Thus, the openings 35 provide access to fabricators to the interior of the column 15 at the location where the side plates 21 are bolted to the column so that standard bolts 26 can be used to attach the side plates to the column. In particular, bolts 26 that require a separate nut 27 (FIGS. 1-3) on the interior or exterior of the column 15 to thread over the bolt 26 to attach the side plate 21 to the column can be used because fabricators can access both ends of the bolts to insert the bolts into the bolt holes 26A and thread the nuts on to the bolts. In the illustrated embodiment, the nuts 27 are disposed on the exterior of the joint connection. However, the nuts could be threaded onto the bolts on the interior of the column 15. In conventional hollow column constructions, specialized bolts (e.g., blind blots) must be used because only the exterior of the column is readily accessible to the fabricators. Therefore, the configuration of the current joint connection facilities the use of standard bolts 26 to connect the gusset plates 21 to the column 15.
Referring to FIGS. 2, 5, and 6, the openings 35 are located at a location on the column 15 that is disposed between the side plates 21 when the side plates are bolted to the column 15. The side plates 21 transfer loads from the beam 19 directly to the first side walls 31. Therefore, the openings 35 located in the second side walls 33 are within the areas of relatively low stress in the joint connection. Thus, the openings 35 will provide access to the interior of the column 15 by removing material of the column without materially degrading the strength of the joint connection. In one embodiment, a center C (FIGS. 5 and 6) of the openings 35 is located at mid height of the opposing side plates 21. Alternatively, the opening 35 can be centered at other locations depending on the load path across the side walls 33 of the column 15.
In the illustrated embodiment, the openings 35 remain open after the side plates 21 are bolted to the column 15. However, the openings 35 can be closed after the side plates 21 are attached to the column using the material of the column 15 removed to form the openings. Alternatively, a separate piece of material may be used to cover the opening 35 after the side plate plates 21 are attached. Additionally or alternatively, a gravity framing member (not shown) may frame into or across the opening 35. It will be understood that closing the openings 35 is not always structurally required for adequate joint connection performance. Thus, one or both of the openings 35 may remain open.
While the illustrated embodiment shows the openings 35 being formed in the beam facing side walls 33, it is further envisioned that openings 36 could additionally or alternatively be formed in one or both of the side walls 31 that engage the side plates 21 (FIG. 7A). In this embodiment, the openings 36 can be located at about mid-height of the side plates 21. In particular, the openings 36 could be in the space within the bolt holes 26A in the side walls 31 of the column 15. Additionally or alternatively, an opening 37 (FIG. 1) can be formed within the confines of beam 20 (i.e., between the upper and lower flanges of beam 20) when the side plates 21 are positioned for attachment to the column 15 and beam 20. In these instances, it is understood that the openings 36, 37 will be located in areas of relatively high stress within the joint connection. Therefore, the openings 36, 37 will be uniquely sized, positioned, and oriented to account for the load path across the side plates 21 and side walls 31 of the column 15. Moreover, the column 15 and/or side plates 21 can be sized and shaped to withstand the stress. The openings 36, 37 may remain open or be closed after the side plates 21 are attached.
Referring to FIGS. 3 and 8-11, the HSS beam 19 includes a hollow beam having open longitudinal ends. However, the longitudinal ends could be closed. In the illustrated embodiment, the beam 19 has a rectangular cross sectional shape defined by four side walls extending along a length of the beam, but could also be other shapes. A first pair of opposing side walls 41 extend across the major (i.e., larger) dimension of the beam 19. The first pair of side walls 41 are configured for engagement with respective side plates 21 when the side plates are bolted to the beam 19. In one embodiment, the side plates 21 extend along substantially an entire height of the first side walls 41. A second pair of opposing side walls 43 extend between the first pair or side walls 41 and define the minor (i.e., smaller) dimension of the beam. The second pair of side walls 43 define the top and bottom of the beam 19 when the beam is bolted to the column assembly 13. It will be understood that the beam 19 could have a square cross-sectional shape such that the first side walls 41 and second side walls 43 have the same lateral dimension. Additionally, the second side walls 43 could have a larger lateral dimension than the first side walls 41.
As discussed above, the side plates 21 reinforce the column 15 and beams 19, 20. With respect to the beams 19, 20, the side plates 21 cause the stresses on the joint connection to be transferred to sides of the joint along the side plates 21 away from the column facing end and top and bottom of the beams 19, 20. Thus, the ends, top and bottom of the beams 19, 20 between the side plates 21 also constitute areas of relatively low stress within the joint connection.
Referring to FIGS. 8 and 9, at least one of the second pair of side walls 43 includes an opening or cut out 45. In the illustrated embodiment, openings 45 are formed in both of the second pair of side walls 43. However, only one of the side walls 43 may have the opening 45, or the openings can be omitted. The openings 45 extend from a longitudinal end of the beam 19 such that they have an open end adjacent the column 15 and a closed end opposite the open end. The openings 45 have a generally rectangular shape with the closed end having rounded corners. The openings 45 extend along the length of the beam 19 such that a longitudinal axis of each opening extends generally parallel to the length of the beam. However, the openings 45 could have other shapes and orientations without departing from the scope of the disclosure. For example, the closed end of the openings 45 may have square corners or the openings may be square or circular in shape. Additionally, the openings 45 may extend in other directions along the surface of the side walls 43 and/or may be located at other positions on the side walls. For instance, the openings 45 may be inset from the end of the beam 19 such that both ends of the opening are closed. The openings 45 provide access to fabricators to the interior of the beam 19 so that standard bolts 26 can be used to attach the side plates 21 to the beam. In particular, bolts 26 that require a separate nut 27 (FIGS. 1-3) on the interior or exterior of the beam 19 to thread over the bolt 26 to attach the side plate 21 to the beam can be used because fabricators can access both ends the bolts to thread the nuts on to the bolts. In conventional hollow beam constructions, specialized bolts (e.g., blind bolts) must be used because only the exterior of the beam is readily accessible to the fabricators. Therefore, the configuration of the current joint connection facilities the use of standard bolts 26 to connect the gusset plates 21 to the beam 19.
Referring to FIG. 3, the openings 45 are located at a position on the beam 19 that is disposed between the side plates 21 when the side plates are bolted to the beam. Therefore, the openings 45 are located within the areas of relatively low stress in the joint connection. Thus, the openings 45 will provide access to the interior of the beam 19 by removing material of the beam without materially degrading the strength of the joint connection. In one embodiment, a center C (FIG. 10) of the openings 45 is located midway between the opposing side plates 21 when the side plates are attached to the beam 19. Alternatively, the openings 45 can be centered at other locations depending on the load path across the side walls 43 of the beam 19.
In the illustrated embodiment, the openings 45 remain open after the side plates 21 are bolted to the beam 19. However, the openings 45 can be closed after the side plates 21 are attached to the beam 19 using the material of the beam removed to form the openings. Alternatively, a separate piece of material may be used to cover the openings 45 after the side plates 21 are attached. Additionally, openings 37 in the side plates 21 can be closed after the side plates are attached to beam 20. It will be understood that closing the openings 37, 45 is not always structurally required for adequate joint connection performance. Thus, some or all of the openings 37, 45 may remain open.
While the illustrated embodiment shows the openings 45 being formed in the top and bottom side walls 43, it is further envisioned that the openings could additionally or alternatively be formed in one or both of the side walls 41 that engage the side plates 21 (FIG. 11A). In this embodiment, the openings 45 can be located at about mid-height of the side plates 21. In this instance, it is understood that the openings 45 will be located in areas of relatively high stress within the joint connection. Therefore, the openings 45 will be uniquely sized, positioned, and oriented to account for the load path across the side walls 41 of the beams 19, 20. The beams 19, 20 and side plates 21 may also be sized and shaped to withstand the additional stress. The openings 45 in the side walls 41 may remain open or be closed after the side plates 21 are attached. Additionally, openings 47 (FIG. 7A) could be formed in the side plates 21 that align or at least partially align with the openings 45 in the side walls 41 of the beam 19 or as needed for beam 20.
Referring to FIGS. 1, 3, and 12-14, beam 20 on the opposite side of the column 15 is bolted to the side plates 21 using angle irons. Upper angle irons 51 are attached to a bottom surface of the top flange of the full-length beam 20. The upper angle irons 51 may comprise elongate L-shaped members including a horizontal first leg attached to the bottom surface of the top flange of the beam 20 at opposite side portions of the beam and extending horizontally along the side portions. The first leg of each upper angle iron 51 is attached in a suitable manner such as by bolts 26 to the bottom surface of the top flange of the beam 20. Each upper angle iron 51 may also include a second leg projecting from the first leg of the upper angle iron and downward, toward the bottom flange of the beam 20. In the illustrated embodiment, the first and second legs of each upper angle iron 51 are disposed at substantially a right angle to each other. An outer surface of the vertical second leg of each upper angle iron 51 is bolted to an inner surface of a respective side plate 21 by horizontally spaced bolts 26 extending through aligned bolt holes 26A in the second leg of the upper angle iron and the side plate 21. In the illustrated embodiment, the upper angle irons 51 are configured such that the horizontal first legs extend laterally past the lateral edges of the top flange of the beam 20 so the outer surfaces of the vertical second legs are disposed laterally away from the flange tips of the top flange of the beam 20. The upper angle irons 51 may be otherwise configured and/or arranged within the scope of the present invention. Additionally, although angle irons 51 are illustrated, other forms of connecting members may be used.
Lower angle irons 53 are attached to a top surface of the bottom flange of the full-length beam 20. The lower angle irons 53 may comprise elongate L-shaped members including a horizontal first leg attached to the top surface of the bottom flange of the beam 20 at opposite side portions of the beam and extending horizontally along the side portions. The first leg of each lower angle iron 53 is attached in a suitable manner such as by bolts 26 to the top surface of the bottom flange of the beam 20. Each lower angle iron 53 may also include a second leg projecting from the first leg of the lower angle iron and upwards, toward the upper flange of the beam 20. In the illustrated embodiment, the first and second legs of each lower angle iron 53 are disposed at substantially a right angle to each other. An outer surface of the vertical second leg of each lower angle iron 53 is bolted to an inner surface of a respective side plate 21 by horizontally spaced bolts 26 extending through aligned bolt holes 26A in the second leg of the lower angle iron and the side plate 21. In the illustrated embodiment, the lower angle irons 53 are configured such that the horizontal first legs extend laterally past the lateral edges of the bottom flange of the beam 20 so the outer surfaces of the vertical second legs are disposed laterally away from the flange tips of the bottom flange of the beam 20. The lower angle irons 53 may be otherwise configured and/or arranged within the scope of the present invention. Additionally, although angle irons 53 are illustrated, other forms of connecting members may be used.
The joint connection structure 11 described above is a beam-to-column-to-beam type structure. It will be understood by a person having ordinary skill in the art that a beam-to-column type structure will have analogous components. Most preferably, each of the components of the joint connection structure 11, as well as the beams 19, 20 and column 15, are made of structural steel. Some of the components of the joint connection structure 11 may be united by welding and some by bolting. The welding may be initially performed at a fabrication shop. The bolting may be performed at the fabrication shop and/or at the construction site, or a combination of the two, which may be a preferred option in many regions of the world.
Referring to FIG. 15 a column assembly of another embodiment is generally indicated at 113. The column assembly 113 includes a column 115 and a pair of side plates 121 bolted to the column. The column assembly 113 is substantially similar to a portion of the column assembly 13 of first embodiment except the side plates 121 comprise channel-shaped plates and extend laterally from only one side of the column 115.
Referring to FIGS. 16-18 a beam-to-column moment-resisting joint connection structure of another embodiment is generally indicated at 211. The joint connection structure may be used in the construction of a building framework. In the illustrated embodiment, the joint connection joins a column assembly 213, including a column 215 and side plates 221, to a full-length beam assembly 217 including a pair of full-length beam channels 219 attached together by a beam tie 223. It will be understood that more than one beam tie (not shown) may be used within the scope of the present invention. In the illustrated embodiment, the column 215 is a hollow rectangular column. However, the column could have other configurations, such an I-beam, H-beam, or circular shape, without departing from the scope of the disclosure. The joint connection structure is substantially similar to a portion of the first embodiment except beam 19 is replaced with the beam channels 219 and tie 223. A gap 245 between the beam channels 219 provides access for bolting the side plates 221 to the beam channels.
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 some of the embodiments to which the advantages and benefits apply.
OTHER STATEMENTS OF THE INVENTION
A1. A method of constructing a column assembly comprising:
- providing a column including a first pair of opposing side walls and a second pair of opposing side walls extending between the first pair of opposing side walls;
- forming a plurality of bolt holes in the first pair of opposing side walls;
- forming an opening separate from the bolt holes in one of the first and second pairs of opposing side walls;
- bolting side plates to the first pair of opposing side walls by accessing bolts extending through the bolt holes through the opening in one of the first and second pairs of opposing side walls.
A2. The method of claim A1, further comprising covering the opening in one of the first and second pairs of opposing side walls after the side plates are attached to the column.
A3. The method of claim A1, further comprising forming a second opening separate from the bolt holes in another of the first and second pairs of opposing side walls.
A4. The method of claim A1, further comprising attaching a beam assembly to the column assembly.
A5. The method of claim A4, wherein attaching the beam assembly comprises:
- providing a beam including a top surface, a bottom surface, and a pair of side surfaces extending between the top and bottom surfaces;
- forming a plurality of bolt holes in each of the side surfaces;
- forming an opening separate from the plurality of bolt holes in the side surfaces in one of the top surface and bottom surface; and
- bolting the side plates to the side surfaces by accessing bolts extending through the bolt holes in the side surfaces through the opening in one of the top surface and bottom surface.
A6. The method of claim A5, further comprising covering the opening in one of the top surface and bottom surface after the side plates are attached to the beam.
Patent Application
20210140168
