Beam-To-Column Connection Assemblies with Erection Support

Abstract

A beam-to-column connection assembly for a building, including a column having a fixture assembly mounted on a side face of the column, and a beam having a fixture assembly on an end portion of the beam. The fixture assemblies are engaged, forming a connection structure joining the column to the beam at a ninety degree angle. The connection structure provides a moment connection between the column and the beam when being assembled with additional beams and columns, and provides a simple connection between the column and beam when the building is fully constructed.

Description

BACKGROUND

Steel frame building construction requires connection of beams and columns, and typically uses a combination of shear connections and moment resisting connections or other moment resisting structures. Pre-fabricated beam connection systems such as collars offer a valuable improvement over on-site welding techniques. Welding can be done off site in controlled conditions, and frame members are seated in the proper spatial orientation when connected by the system.

Pre-fabricated moment resisting connections such as full moment collars offer advantages in speed and ease of building frame erection, but may not be desirable for all building designs. “Simple” or “standard” shear connections are generally lighter, less expensive, and applicable to a wide range of building designs. However, standard shear connections are not self-supporting during erection and require support cables, early installation of braced frames, or other support provisions, adding cost and additional erection time to a construction project.

A simple and cost effective pre-fabricated connection system that can be used in place of a standard shear connection in building designs, while providing the self-supporting frame advantages of full moment connections during erection, would be highly desirable.

SUMMARY

The present disclosure provides systems, apparatus, and methods relating to connecting beams and columns in a building frame. In some examples, a beam-to-column connection assembly for a building may include a column having a fixture assembly mounted on a side face of the column, and a beam having a fixture assembly on an end portion of the beam. The fixture assemblies may be engaged, forming a connection structure joining the column to the beam at a ninety degree angle. The connection structure may provide a moment connection between the column and the beam when being assembled with additional beams and columns, and provide a simple connection between the column and beam when the building is fully constructed.

In some examples, construction assembly may include a steel beam and a column. The beam may have a first end portion including a web portion, a top flange portion, and a bottom flange portion, and the column may have a side face with a beam engagement structure mounted on the side face of the column. A first brace fixture may be mounted on the top flange portion, and a second brace fixture may be mounted on the bottom flange portion. Each of the first and second brace fixtures may be connected to the beam engagement structure of the column, providing a moment connection between the beam and the column.

In some examples, a beam-to-column connection assembly for a building may include a column having a fixture assembly mounted on a side face of the column, and a beam having a fixture assembly on an end portion of the beam. The fixture assemblies may be engaged to form a connection structure joining the column to the beam at a ninety degree angle. The connection structure may include means for providing a moment connection when the column and beam are being assembled with additional beams and columns, and to provide a simple connection between the column and beam when the building is fully constructed.

Features, functions, and advantages may be achieved independently in various examples of the present disclosure, or may be combined in yet other examples, further details of which can be seen with reference to the following description and drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a beam and two columns of a steel building frame bay, in a default position.

FIG. 2 is a schematic diagram of the beam and columns of FIG. 1, racked in response to horizontal loading.

FIG. 3 is a schematic diagram of the beam and columns of FIG. 1, with the beam deflected under vertical loading.

FIG. 4A is a schematic graph of moment-rotation curves for a standard full moment connection, a standard shear connection, and an illustrative erection support shear connection (ESSC) as described herein.

FIG. 4B is a schematic graph of slopes of the moment-rotation curves of FIG. 4A.

FIG. 5A is an isometric view of a standard single-plate shear connection as known in the prior art.

FIG. 5B is a schematic diagram of the connection of FIG. 5A.

FIG. 6A is a schematic diagram of an illustrative ESSC as described herein, in an erection phase configuration.

FIG. 6B is a schematic diagram of the ESSC of FIG. 6A, in a service phase configuration.

FIG. 7 is a schematic diagram of a section of a steel building frame plan, including ESSC's.

FIG. 8 is an isometric view of a column and a beam, connected by an illustrative ESSC as described herein, in a service phase configuration.

FIG. 9 is an isometric view of the ESSC of FIG. 8, in an un-connected configuration.

FIG. 10 is a side elevation view of the ESSC of FIG. 8, in an un-connected configuration.

FIG. 11 is a side elevation view of the ESSC of FIG. 8, in an erection phase configuration.

FIG. 12 is a side elevation view of the ESSC of FIG. 8, in the service phase configuration.

FIG. 13 is a top plan view of the ESSC of FIG. 8, in the service phase configuration.

FIG. 14 is a rear plan view of the ESSC of FIG. 8, in the service phase configuration.

FIG. 15 is an isometric view of another illustrative ESSC as described herein, in an un-connected configuration.

FIG. 16 is a side elevation view of the ESSC of FIG. 15, in a service phase configuration.

FIG. 17 is a top plan view of the ESSC of FIG. 16.

FIG. 18 is an isometric view of another illustrative ESSC as described herein, in an un-connected configuration.

FIG. 19 is a side elevation view of the ESSC of FIG. 18, in a service phase configuration.

FIG. 20 is a top plan sectional view of the ESSC of FIG. 19, along line 20-20 in FIG. 19.

FIG. 21 is an isometric view of another illustrative ESSC as described herein, in an un-connected configuration, with one channel plate depicted as transparent.

FIG. 22 is a side elevation view of the ESSC of FIG. 21, in an erection phase configuration.

FIG. 23 is a detail view of a web cleat received in a channel plate of the ESSC of FIG. 21, in isolation.

FIG. 24 is an isometric side view of another illustrative ESSC connecting a column and four beams.

FIG. 25 is a top plan view of the ESSC, column, and beams of FIG. 24.

FIG. 26 is an isometric side view of a corner assembly of the ESSC of FIG. 24.

FIG. 27 is an isometric side view of a flange assembly of the ESSC of FIG. 24.

DETAILED DESCRIPTION

Various aspects and examples of a beam-to-column connection assembly, as well as related systems and methods, are described below and illustrated in the associated drawings. Unless otherwise specified, a connection assembly in accordance with the present teachings, and/or its various components may, but are not required to, contain at least one of the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein. Furthermore, unless specifically excluded, the process steps, structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein in connection with the present teachings may be included in other similar devices and methods, including being interchangeable between disclosed examples. The following description of various examples is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. Additionally, the advantages provided by the examples described below are illustrative in nature and not all examples provide the same advantages or the same degree of advantages.

This Detailed Description includes the following sections, which follow immediately below: (1) Definitions; (2) Overview; (3) Examples, Components, and Alternatives; (4) Illustrative Combinations and Additional Examples; (5) Advantages, Features, and Benefits; and (6) Conclusion. The Examples, Components, and Alternatives section is further divided into subsections A through E, each of which is labeled accordingly.

Definitions

The following definitions apply herein, unless otherwise indicated.

“Substantially” means to be predominantly conforming to the particular dimension, range, shape, concept, or other aspect modified by the term, such that a feature or component need not conform exactly, so long as it is suitable for its intended purpose or function. For example, a “substantially cylindrical” object means that the object resembles a cylinder, but may have one or more deviations from a true cylinder.

“Comprising,” “including,” and “having” (and conjugations thereof) are used interchangeably to mean including but not necessarily limited to, and are open-ended terms not intended to exclude additional, unrecited elements or method steps.

Terms such as “first”, “second”, and “third” are used to distinguish or identify various members of a group, or the like, in the order they are introduced in a particular context and are not intended to show serial or numerical limitation, or be fixed identifiers for the group members.

“And/or” is used to mean all combinations of the listed elements. For example, a list with two elements “A and/or B” covers three possibilities: only A, only B, or both A and B. Similarly, a list with three elements “A, B, and/or C” covers seven possibilities: only A, only B, only C, both A and B, both A and C, both B and C, or all three (A, B, and C). The extension to four or more elements follows the same pattern.

“Coupled” means to be in such relation that the performance of one influences the performance of the other, may include being connected, either permanently or releasably, whether directly or indirectly through intervening components, and is not necessarily limited to physical connection(s).

The term “about” as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of +/10% or less, preferably +/−5% or less, more preferably +/−1% or less, and still more preferably +/−0.1% or less of the specified value, insofar such variations are appropriate to perform in the disclosure. It is to be understood that the value to which the modifier “about” refers is itself also specifically, and preferably, disclosed.

The terms “beam”, “column”, “simple connection”, “moment connection”, “fully restrained connection”, and “partially restrained connection” as used herein are to be understood as defined in the American Institute of Steel Construction (AISC) and American National Standards Institute (ANSI) code: ANSI/AISC 360-16 Specification for Structural Steel Buildings.

In particular: a beam is a nominally horizontal structural member that has the primary function of resisting bending moments. A column is a nominally vertical structural member that has the primary function of resisting axial compressive force.

A simple connection is a connection that transmits negligible bending moment between connected members. There are two types of moment connection: a fully restrained moment connection or fully restrained connection, which is a connection capable of transferring moment with negligible rotation between connected members; and a partially restrained moment connection or partially restrained connection, which is a connection capable of transferring moment with rotation between connected members that is not negligible.

The secant stiffness K_s, at service loads is taken as an index property of connection stiffness. Specifically, K_s=M_s/θ_s where M_s is moment at service loads, θ_s is rotation at service loads. Where L and EI are the length and bending rigidity of the beam, if K_s L/EI≥20, it is acceptable to consider the connection to be fully restrained (in other words, able to maintain the angles between members). If K_s L/EI≤2, it is acceptable to consider the connection to be simple (in other words, it rotates without developing moment). Connections with stiffnesses between these two limits are partially restrained and the stiffness, strength and ductility of the connection must be considered in the design.

In the disclosure, the terms “simple connection”, “pinned connection”, and “shear connection” may be used interchangeably unless otherwise specifically stated. Similarly, the terms “fully restrained connection” and “full moment connection” may be used interchangeably, and the terms “partially restrained connection” and “flexible moment connection” may be used interchangeably unless otherwise specifically stated.

Overview

In general, a beam-to-column connection assembly with erection support may include a column, a beam, and a connection structure. A fixture assembly mounted on a side face of the column and a fixture assembly on an end portion of the beam may engage to form the connection structure, joining the beam to the column such that the connection structure provides a moment connection between the column and beam when being assembled with additional beams and columns, and provides a simple connection between the column and beam in a fully constructed building. In other words, the formed connection structure transfers a useful amount of moment under conditions and loads associated with building frame erection, but does not transfer a significant amount of moment under conditions and loads associated with a constructed building in service. Such a connection structure may also be referred to as an erection support shear connection (ESSC).

In a steel building frame, an ESSC may be used to connect one end of a beam to a column. For instance, the beam may be an I-beam and the column may be a W-flange, HSS, or box column. Often, each end of the beam will be connected to a column by an ESSC. In some examples, one end of the beam may be connected by an ESSC while the opposite end is connected by another connection type such as a standard shear connection.

An ESSC may be designed to transfer minimal or negligible moment through some initial range of beam rotation, and transfer significant moment beyond that range. The ESSC may suddenly increase in rotational stiffness, or gradually increase in rotational stiffness. The increase in rotational stiffness may be associated with changes in engagement between elements of the connection, characteristics of materials of the connection, and/or any relevant factors.

An ESSC may include a variety of structures to achieve the appropriate transfer of forces. According to the structures included, an ESSC may also be referred to as a delayed moment connection, a variable moment connection, a limited moment connection, and/or a hybrid shear connection.

In some examples, there may be one or more gaps between components of an ESSC. Such an ESSC may be referred to as a delayed moment connection (DMC). The beam-side structure may be free to rotate relative to the column-side structure until a gap is closed by the rotation, and corresponding surfaces on the column-side and beam-side structures contact one another. The size and shape of the gaps may be selected and/or designed such that the corresponding surfaces engage at a desired degree of rotation, and/or a desired area of the corresponding surfaces makes contact. The area of contact, the shape of the corresponding surfaces, the position and/or structural role of the components on which the surfaces are located may affect the amount of moment transferred by the DMC.

In some examples, an ESSC may qualify as a flexible moment connection or partially restrained connection under building code or standards. Such an ESSC may be referred to as a limited moment connection (LMC). The LMC may be configured according to the properties of a beam connected, in order that the increase in rotational stiffness results in transfer of minimal moment in a range of rotation associated with building service conditions, but transfer of sufficient moment outside that range to provide effective erection support.

FIGS. 1-3 are schematic depictions of a beam 102 and two columns 104, 105 of one bay of a steel building frame. Beam 102 is connected to columns 104, 105 respectively by shear connections 106, 107 of some type. The sizes and angles of the components are not depicted to scale. The bay may further include any number of other floors, formed by other beams (not depicted) connected between columns 104, 105.

A connected beam and column may form a relative angle, such as angle 108 between beam 102 and column 104. The nominal or building plan design value may often be a ninety degree angle, or right angle, as shown in FIG. 1. Connections 106, 107 may be described as joining the beam to the columns at a 90 degree angle, or in a perpendicular orientation.

The beam and column may also be referred to as having an angle of relative rotation, measured as a deviation of angle 108 from a building plan design value or the absolute value thereof. Angle 108 and the angle of relative rotation may vary as the beam and column experience loads.

During erection, the bay may experience horizontal loading such as wind, as indicated by arrow 110 in FIG. 2. Horizontal loading may cause the bay to rack, with the columns each deviating from vertical while the beam remains substantially horizontal. Angle 108 may decrease as a result. If connections 106, 107 are standard shear connections, then the racking motion may continue unimpeded until the bay collapses, unless restrained by other structures such as support cables.

In contrast, if connections 106, 107 are ESSC, then the connections may increase in rotational stiffness and/or begin to resist rotation at some point. Elements of the connection may contact or engage, causing moment transfer between the beam and columns. The connections may be stiff enough to develop sufficient moment to resist racking of the bay, and prevent collapse. Support structures such as cables may therefore not be needed, simplifying construction.

Once construction of the building is complete, the bay may experience primarily vertical loading such as the weight of floors and walls, as indicated by arrow 112 in FIG. 3. Horizontal loading may be handled by other structures in the completed building such as braced frames or shear walls. However, the vertical loading may be sufficient that the beam deflects, or curves, as schematically depicted.

Beam deflection may also cause rotation of the end of beam 102 relative to column 104 at connection 106, resulting in a change of angle 108. To meet building codes, beam 102 may be sufficiently stiff to support building loads without deflecting more than a predetermined amount. For example, there may be a beam-end rotation angle that results from a maximum allowable mid-span deflection and the length of beam 102.

As mentioned above, a standard shear connection may not substantially resist rotation of beam 102. An ESSC may also not substantially resist rotation of beam 102 within the range of rotation corresponding to the maximum deflection for the beam's length. Therefore, for all rotation the beam can be expected to experience during service of the building, the ESSC may be considered and/or act as a simple connection, with zero moments considered.

FIG. 4A is a schematic version of a graph of moment rotation curves of three connection types for a selected arbitrary beam. A curve 202 of a full moment or fully restrained connection, a curve 204 of a shear or simple connection, a curve 206 of a first illustrative ESSC, and a curve 207 of a second illustrative ESSC are shown.

The rotational range is divided into a service range 208, an erection range 210, and an out of standard range 205. Service range 208 includes all angles of relative rotation allowed under building code for a completed building and associated loads. Range 208 may have an upper bound at an angle 209. Angle 209 may be a maximum allowable angle of relative rotation for a connected beam and column in an in-service building. Range 210 includes all angles of relative rotation greater than angle 209 that are seen during building frame erection under building site safety regulations and/or standard practice.

Angle 209 and/or range 210 may be determined according to a relevant building code and/or safer standard. The relevant code or standard may depend on the type, size, and/or location of the building as well as the size, shape, and/or material of the connected beam and column, and/or other beams and columns of the building. For example, angle 209 may be the beam-end rotation angle that results from the length of a steel beam and a maximum allowable mid-span deflection as defined by the AISC.

As shown, curve 206 changes slope and overall shape at an angle 211 in erection range 210. In the depicted example the change is sharp, but for other ESSC connections the change may be gradual and/or the moment-rotation curve may be smooth throughout. For relative rotation up to angle 211, ESSC curve 206 is similar to shear connection curve 204. At angle 211 and above, ESSC curve 206 is steeper in slope and may be described as between a full moment and shear connection.

The change in shape of curve 206 at angle 211 reflects a change in the rotational stiffness of a DMC at that angle of relative rotation. Whereas, curve 207 maintains a consistent shape reflecting the gradual increase of rotational stiffness of an LMC. The first illustrative ESSC may be a DMC and the second illustrative ESSC may be a LMC, as described above.

FIG. 4B is a schematic graph of the slopes of the moment rotation curves of FIG. 4A. The slopes may also be referred to as the secant stiffness K, which the AISC specification commentary takes as an index property of connection stiffness at service loads. That is, the moment rotation curve slope or secant stiffness in range 208 may be considered as indexing the connection stiffness.

Depicted in FIG. 4B are ranges 208 and 210 as described above, slope 202S of moment curve 202 of the illustrative full moment connection, slope 204S of moment curve 204 of the illustrative shear connection, slope 206S of moment curve 206 of the first illustrative ESSC connection, and slope 207S of moment curve 207 of the second illustrative ESSC connection. Also depicted are boundaries 212 and 214.

Above boundary 212 are moment-rotation curve slopes characteristic of a full moment connection, and below boundary 214 are moment-rotation curve slopes characteristic of a shear connection. The boundaries may be defined under a building code or standard, or otherwise established. For example, under AISC specification commentary, boundary 212 may be given by the formula K=(20*E*I)/L, where E is Young's modulus for the beam material of a connected beam, I is the area moment of inertia of the beam, and L is the length of the beam. Similarly, as outlined in the AISC specification commentary, boundary 214 may be given by the formula K=(2*E*I)/L.

As shown, moment curve slopes 206S and 207S each cross boundary 214. The slopes of the curves 206, 207 are less than the boundary value until angle 211. This may indicate that each of the first and second illustrative ESSC's acts as a shear connection until a connected beam has rotated to angle 211. Since angle 211 is in erection range 210 and greater than the angles of service range 208, each ESSC may qualify as a shear connection for building design purposes. That is, each ESSC may be used in a building design with zero moments considered.

At angle 211, moment curve 206 is discontinuous and jumps up to a higher slope, while moment curve 207 continues a linear increase in slope. This may indicate that the first illustrative ESSC exhibits a sudden or significant change in rotational stiffness at angle 211, while the second illustrative ESSC exhibits a gradual increase in rotational stiffness through ranges 208, 210.

These characteristics of the rotational stiffness of the illustrative ESSC's may be achieved by any appropriate connection structures and/or mechanisms. For example, the first illustrative ESSC may include one or more gaps between components, which may close and the components contact at angle 211. For another example, the second illustrative ESSC may include a standard shear connection modified to have overall increased rotational stiffness.

In the depicted example, each ESSC transfers more moment than a standard shear connection as represented by curve 204, even in service range 208. In some examples, an ESSC may transfer essentially no moment at low ranges of rotation and may have a smaller slope than shear connection curve 204 in the service range. In some examples, an ESSC may transfer slightly more moment than a code definition of a shear connection, and have a slope slightly above boundary 214 for some or all of service range 208. In such examples, structural analysis may be done or other provisions made to ensure that the ESSC can be appropriately used in place of a standard shear connection. Alternatively, in such examples, the ESSC may be used in a building design created specifically for the capabilities of the ESSC.

In the depicted example, slopes 206S, 207S of the ESSC's do not cross boundary 212, and neither ESSC has rotational stiffness comparable to a full moment connection at any angle of relative rotation. In some examples, an ESSC may transfer as much moment as a full moment connection for some range of rotation. In some examples, the slope of an ESSC's moment-rotation curve may not cross boundary 214, but the ESSC may have sufficient rotational stiffness, at least for some subset of angles in range 210, to provide effective erection support.

As stated above, FIGS. 4A and 4B are depicted for a selected arbitrary beam. In general, curves 202, 204, 206, and 207 may vary depending on properties of a given beam. An ESSC may be designed to have a desired moment-rotation curve for a selected range of beam lengths and/or other relevant beam properties. A particular ESSC may not provide sufficient or appropriate erection support for all beams. Delayed moment connections such as the first illustrative ESSC with curve 206 may be useful for a broader range of beam sizes, and may be appropriate for use as a standard part across many building designs. Whereas, as the second illustrative ESSC with curve 207 may be better configured for a small range of beam sizes, and may be appropriate for use as a custom designed part for a specific building design.

FIG. 5A is an isometric view of a standard single-plate or single-clip shear connection 300, as known in the prior art. A beam 302 is connected to a column 304, by a plate 310. The plate is welded to one face of column 304, and may be referred to as a shear plate or shear clip. Plate 310 is fastened to a web of beam 302, by a pair of bolts 308 through aligned apertures in the plate and beam web. To connect beam 302 to column 304 with connection 300, the beam may be lifted into position next to the plate by a crane. Bolts 308 may be installed while the crane supports the beam. Even after the connection is completed, column 304 may need support from cables until moment-resisting structures of the building frame are erected.

A double-plate or double-clip shear connection may be similar, but include a second plate welded to the column face parallel to plate 310 but spaced from the plate. The web of beam 302 may be received between the two plates. The beam may include a bottom cope, or a cutaway of the lower flange at the beam end to allow the web to pass between the two shear plates without interference from the beam flange.

FIG. 5B is a schematic diagram of shear connection 300. The connected beam 302 includes web holes 312, and the column 304 includes a shear clip 310. The web holes are connected to the shear clip by fasteners 308, such as bolts. This connection may function equivalently throughout both erection and service phases of a building.

FIGS. 6A and 6B are schematic diagrams of an illustrative ESSC 400, as connected in a configuration appropriate for the frame erection phase of a building and a configuration appropriate to the service phase of the building, respectively. ESSC 400 may be described as incorporating a standard shear connection with other, erection-support connection structures. Specifically, ESSC connects a beam 402 to a column 404. The standard shear connection includes one or more shear clips 410 fixed to column 404, and corresponding web holes 412 in beam 402.

In addition, ESSC 400 includes a positioning structure formed by engagement of a beam-end fixture assembly 414B and a column-side fixture assembly 414C. Similarly, the ESSC includes a retention structure of beam-end and column-side fixture assemblies 424B, 424C; a moment structure of beam-end and column-side fixture assemblies 424B, 424C; and a shear structure of beam-end and column-side fixture assemblies 416B, 416C.

In the erection phase configuration, shown in FIG. 6A, the double-plate shear connection is not bolted or otherwise fastened. The beam-end and column-side fixtures of each additional connection structure engage in the erection phase configuration of the ESSC. Some or all of the corresponding beam-end and column-side fixtures may engage to form the respected connection structure when the beam is lowered into position relative to the column.

Each of these additional structures may play a role in providing effective erection support, and improving speed and ease of building frame erection. In general, additional structures of an ESSC may be configured to engage and transfer moment, have a desired stiffness, and/or provide erection support in any effective manner.

The additional connection structures may be separate from and/or integrated with standard shear connection structures. For instance, structures may cooperate to connect one or both flanges of the beam to the column. For instance, structures may cooperate to connect the web of the beam to the column independently of the shear plates. For instance, structures may be mounted to and/or engage with the shear plates.

In some examples, one structure may perform two or more functions. For instance, a structure may provide both positioning and retention functionality. In some examples, an ESSC may include separate load paths for moment and shear loads. In some examples, an ESSC may include a load path along which both moment and shear loads are transferred.

Shear structure 416 may support the beam prior to fastening of beam-end components of the connection to column-side components of the connection. While vertical loading from sources such as the weight of the beam itself may be negligible for most shear connection types, the weight of the beam must still be supported either by the connection or external supports until the connection is fastened.

An ESSC may include any structures appropriate to support the weight of the beam, in cooperation with the connection at the opposite end of the beam. For instance, an ESSC may include a gravity catch structure, a protrusion such as a ledge, or a pair of corresponding structures such as a hook or post and an aperture. The support structures of the ESSC may engage as a beam is lowered into position, without separate installation or manual positioning by workers. The ESSC may provide sufficient support to allow the beam to remain in place without external supports, prior to the installation of any fasteners.

Moment structure 422 may resist racking of the frame past a desired range of rotation, as described above with reference to FIGS. 1-4B.

Positioning structure 414 may facilitate correct alignment of the connected beam and column. Correct alignment may include alignment of corresponding apertures in beam-end components and column-side components for installation of fasteners, relative angle between beam and column, and/or any relevant spatial relationship between beam, column, and/or connection components. For instance, an ESSC may include corresponding structures such as a post and a slot or a tapered protrusion and an aperture. The alignment structures of the ESSC may engage and guide a beam into position as the beam is lowered, without separate installation or manual positioning by workers.

Retention structure 424 may hold the beam in place prior to fastening of the beam web to the shear plates. Such a feature may be described as a retention and/or lock mechanism. Such a feature may include a beam-end fixture and a column-side fixture which engage as a beam is lowered into position, but resist disengagement if a beam is lifted or otherwise moved. For instance, an ESSC may include a snap-fit or latch element. The retention structures of the ESSC may engage as a beam is lowered into position, without separate installation or manual positioning by workers.

In the service phase configuration, shown in FIG. 6B, web holes 412 of beam 402 are connected to shear clips 410 of column 404 by fasteners 408, such as bolts or pins. The additional connection structures 414, 416, 422, 424 remain engaged, but are no longer relevant to the loads experienced by the ESSC. The ESSC may act effectively as a standard shear connection.

FIG. 7 depicts a section of a plan for a steel building frame 120, including ESSC's 130. The frame includes columns 104 and beams 102. The frame elements are connected by ESSC's 130, pinned connections 136, and bracing 138.

Frame 120 includes a group of four columns 104A, which may be described as a tower assembly, or support tower 142. Each of the four columns 104A are connected to adjacent beams by ESSC's 130, and the columns are interconnected by four beams 102A. Tower 142 may be self-supporting.

Frame 120 also includes columns 104B, to which beams are connected only by a pinned or simple connection. Some beams 102A have ESSC components fixed at both ends. Some beams 102B may have ESSC components fixed at only one end, and a pinned connection at the other end. Some beams 102C are connected to adjacent columns only by pinned connections. Some beams 102D are part of a braced frame, or braced bay with bracing 138.

During erection of building frame 120, tower 142 may be erected first, and provide support to columns 104B which are connected to adjacent columns only through pinned connections. That is, ESSC's 130 may resist the moment loads associated with erection of connected columns. Once all columns of the supported section of building frame 120 are erected, bracing 138 may be installed. Such a method may avoid the need for bracing to be installed first, or for supports such as cables or cranes to be used to keep columns upright while bracing is installed.

Once building frame 120 is completed, and the full building constructed, ESSC's 130 may act similarly or equivalently to pinned connections 136. Resistance to lateral loading may be provided by other elements of the building frame, such as bracing 138. The bracing may be designed and positioned as though ESSC's 130 were simple connections. Other moment resisting frame elements may additionally or alternatively be used. For example, braced frames may be selected where seismic loading is expected, while shear walls may be used instead where seismic tolerance is not needed. Such moment resisting elements may be used according to standard design principles, without need to account for ESSC's 130 in the completed building design.

For another example, ESSC's 130 may be used to replace simple connections in an existing building design. Such a design change may simplify and reduce construction time, without requiring overall redesign of the building.

In general, a beam-to-column connection assembly with erection support may include a column-side fixture and a beam-end fixture, which engage to form a connection structure joining the beam to the column. The column-side fixture may include a clip structure which couples to first and/or second brace structures of the beam-end fixtures, where the first brace structure is on an upper flange of the beam and the second brace structure is on a lower flange of the beam.

The clip structure may include a shear plate or shear clip such as shear plate 310 of standard shear connection 300, described above. The clip structure may further include tabs, reinforcements, vertical or horizontal plates, and/or any elements suitable to desired transfer of loads.

The first and/or second brace structure may include a plate, angle iron, bracket, and/or any elements suitable to desired transfer of loads. In some examples, the clip structure may couple directly to the upper or lower flange of the beam in place of a brace structure.

The clip structure and brace structure(s) may be coupled and/or lockingly engaged by one or more pins. Each pin may be a separate structure or may be integrated with either the clip structure or one of the brace structures. Each separate pin may be received through aligned apertures of both the clip structure and one of the brace structures. Each pin integral to the clip structure may be received through an aperture in one of the brace structures, and each pin integral to one of the brace structure may be received through an aperture of the clip structure. Each pin may extend parallel or perpendicular a long axis of the beam.

In some examples, the pin may be smaller than the apertures through which the pin extends. That is, a gap may form between the pin and side of the aperture. The pin may be described as having range of free movement in the aperture. Rotation of the beam relative to the column may bring surface of the pin and the aperture into contact after an initial range of rotation. The contacting surfaces may transfer moment between the beam and column. The contacting surfaces may be referred to as bearing surfaces, and may be configured to provide desired rotational stiffness.

The connection structure may be designed according to the size of a particular beam, class of beams with which the connection structure may be used, type of building in which the connection structure may be used, and/or any relevant factors. For example, a size of the gap between a pin and the side of the aperture may be selected according to a beam size. For another example, a size of the bearing surface may be selected according to the material(s) of the connection structure and expected moment loads.

Examples, Components, and Alternatives

The following sections describe selected aspects of exemplary beam-to-column connection assemblies as well as related systems and/or methods. The examples in these sections are intended for illustration and should not be interpreted as limiting the entire scope of the present disclosure. Each section may include one or more distinct examples, and/or contextual or related information, function, and/or structure.

A. Illustrative Flange Bracket Delayed Moment Connection

As shown in FIGS. 8-14, this section describes an illustrative beam-to-column connection assembly of a steel building frame, including a column 504, a beam 502, and a connection 500. The assembly may also be referred to as a construction assembly. Connection 500 is an example of an erection support shear connection (ESSC) and a delayed moment connection (DMC), as described above.

In the present example, column 504 is a W-flange column, including a web portion 584 connecting first and second flanges 582. Beam 502 is an I-beam, also having a web portion 554 connecting upper and lower flanges 552. Connection 500 joins an end portion of the beam to an outer side of one of flanges 582 of the column, at a ninety degree angle. The beam and column are depicted in isolation, but may form part of a bay and/or a building frame.

In some examples, column 504 may be an HSS or box column. Beam 502 may be any appropriate weight or size of I-beam. A plurality of beams may be connected to either of flanges 584 and/or web 554 of the column. Up to four beams may connect at a single node, or vertical location on the column, and/or beams may connect at a plurality of nodes spaced along the vertical extent of the column.

Connection structure 500 may be described as formed by engagement between a first fixture assembly mounted to beam 502 and a second fixture assembly mounted to column 504. In FIGS. 9 and 10, the connection is depicted in an un-connected configuration, with the fixture assemblies not engaged. In FIGS. 8 and 11-14 the fixture assemblies are engaged, with connection 500 shown in an erection phase configuration in FIG. 11, and in a service phase configuration in FIGS. 8 and 12-14.

As shown in FIGS. 9-10, the fixture assembly of beam 502 includes an upper bracket and a lower bracket. In the present example, the upper bracket comprises a pair of angle irons 518, and the lower bracket comprises a pair of angle irons 520. Each angle iron 518, 520 may be described as having a horizontal flange and a vertical flange. A portion of the horizontal flange of each angle iron 518 is fixed to an upper surface of the upper flange 552 of beam 502, extending out over an upper cope 593 in web 554 of the beam. Similarly, a portion of the horizontal flange of each angle iron 520 is fixed to a lower surface of the lower flange 552 of beam 502, extending out under a lower cope 592 in web 554 of the beam.

The vertical flange of each angle iron 518 includes a bracket hole 519, and the vertical flange of each angle iron 520 includes a bracket hole 521. Bracket holes 519 are aligned to receive a first pin 514, and bracket holes 521 are aligned to receive a second pin 514.

In some examples, the upper and/or lower bracket may include additional and/or alternative components, and may be secured to a flange of the beam in any effective way. For example, the bracket may include a pair of vertical plates instead of angle irons, or may include only the vertical flange of the angle irons as depicted in the present example. For example, plates, angle irons, and/or other bracket components may be welded or fastened to the beam flange, and may be secured to an exterior surface of the beam flange as depicted or may be secured to a side or inner surface of the flange.

The fixture assembly of column 504 includes a pair of shear plates 510. Each shear plate has a vertical series of holes 511 in a center section. At a top end of each shear plate is a first doubler plate 512, and at a bottom end of each shear plate is a second doubler plate 516. An upper clip hole 513 extends through both doubler plates 512 and shear plates 510, and a lower clip hole 517 extends through both doubler plates 516 and shear plates 510.

In the present example, a bar 515 is fixed between shear plates 510, below holes 511 and above doubler plates 516. In some examples, a fastener such as a bolt or snap-fit pin may be installed through a lowermost hole 511 of the vertical series, prior to positioning of the beam and engagement between the fixture assemblies of the beam and the column. In some examples, the fixture assembly may include a separate support structure below shear plates 510, and integrated with or separate from a lower structure including lower clip hole 517.

The upper bracket of angle irons 518 and the lower bracket of angle irons 520 are each examples of a brace structure or a brace fixture as described above. Shear plates 510, doubler plates 512, 516, and bar 515 together are an example of a clip structure, as described above. First and second pins 514 may be described as coupling the brackets to the shear plates, or as connecting the fixture assemblies via locking engagement.

In the present example, pins 514 are cylindrical and may also be described as dowels. In some examples, the pins may include features such as a head and/or a snap-fit portion and/or the pins may be part of a fastener assembly. Each pin has an elongate axis 594. When positioned to couple the brackets to the shear plates, as in FIGS. 11-14, elongate axis 594 may be perpendicular an elongate axis of beam 502 (FIG. 10).

Web 554 of beam 502 includes a plurality of vertically aligned holes 557, corresponding to holes 511 of shear plates 510. At lower cope 562, the web further includes a notch 525, positioned and shaped to correspond to bar 515.

To engage the beam and column fixtures of connection 500, an end portion of beam 502 may be brought adjacent to column 504, and lowered with web 554 received between shear plates 510 until notch 525 receives bar 515. The notch and bar may position the beam such that beam web holes 557 are aligned with shear plate holes 511, upper bracket holes 519 are aligned with upper clip hole 513, and lower bracket holes 521 are aligned with lower clip hole 517. A bevel at a top end of each doubler plate 512, 516 may help to prevent catching or binding of angle irons 518, 520 as the beam is lowered.

Pins 514 may be inserted through the aligned bracket and clip holes 513, 519 and 517, 521, once the beam is lowered into position. Notch 525 may rest on bar 515, transferring sufficient shear loads from the beam to the column to support the weight of the beam in the erection phase configuration. The pins may retain beam 502 in position, and may provide delayed transmission of bending moment as described above.

As shown in FIG. 10, clip holes 513, 517 are each larger than pins 514. Each hole may be described as an elongate aperture or slot, and has an extent or long axis 596. Long axis 596 of the clip holes is perpendicular to both long axis 592 of beam 502 and axis 594 of pins 514 (FIG. 9). Each hole 513, 517 has an extent 572 along axis 596. Each pin 514 is circular with a diameter 574, and extent 572 of holes 518, 517 is greater than diameter 574 of pins 517.

This difference in size may form a gap between adjacent surfaces of the pins and holes. The position and size of the gap may change as the beam moves and/or rotates relative to the column. The gap may also provide the delay in moment transfer. That is, as described above, connection 500 may not transfer moment through an initial range of rotation of the beam. In this example, moment may not be transferred until one of pins 514 contacts shear plates 510 and either doubler plates 512 or 516 at an outer edge of the respective clip hole 513, 517.

Doubler plates 512, 516 may be described as stiffening the top and bottom ends of shear plates 510. That is, the doubler plates may increase a bearing surface where pins 514 contact the shear plates after the gap is closed and the beam has rotated through the initial rotation range. The increased area may reduce the pressure created by the rotational loads transferred through the pins.

In FIG. 14, connection 500 is shown in the service phase configuration. Once beam 502 and column 504 have been assembled with additional beams and columns of the building frame, fastener assemblies 508 may be installed to provide the full shear capacity of the connection. In the depicted example, each fastener assembly 508 includes a bolt and a nut. Each bolt is installed through one of holes 511 of each shear plate 510 and one of holes 557 of web 554.

B. Illustrative Horizontal Plate Delayed Moment Connection

As shown in FIGS. 15-17, this section describes an illustrative beam-to-column connection assembly of a steel building frame, including a column 604, a beam 602, and a connection 600. Connection 600 is an example of an erection support shear connection (ESSC) and a delayed moment connection (DMC), as described above.

A pair of shear plates 610 with a plurality of vertically aligned holes 611 are mounted to a side face of column 604. The size of the shear plates and the number of holes may depend on the size of the beam. A pair of lugs 612 are mounted above the shear plates, each lug having an upwardly projecting tapered pin or tooth 614. A horizontal plate 616 is mounted below shear plates 610, extending out past the shear plates to support a further pair of tapered teeth 614.

Each tooth has an elongate axis 694. The elongate axis of teeth 614 may be described as oriented vertically, and/or as oriented perpendicular to a long axis 692 of beam 602 (see FIG. 17).

Beam 602 is an I-beam, with a web 654 between upper and lower flanges 652. Web 654 of beam 602 includes a plurality of vertically aligned holes 657, corresponding to holes 611 of shear plates 610. The beam also has a lower cope 662 and upper cope 663, to allow the web of the beam to engage the column-side fixture of the connection without interference from the beam flanges.

An upper beam plate 618 is mounted to the top flange of the beam, and a lower beam plate 620 is mounted to the bottom flange of the beam. Upper beam plate 618 includes a pair of apertures 619 and lower beam plate 620 includes a pair of apertures 621. The lower beam plate extends out less than beam web 654, such that the plate does not obstruct passage of the web between shear plates 610.

Apertures 619 and 621 are each larger than teeth 614, as best shown in FIG. 17. In the present example, teeth 614 are all of the same size, and apertures 619 match apertures 621. In some examples, the size of teeth and/or apertures may differ between the upper and lower portions of the connection.

As shown in FIG. 17, teeth 614 may be described as forming both a lateral gap and a longitudinal gap 622 with the respective apertures. The gaps may allow tolerance for installation, while tapering of teeth 614 may help guide the beam into alignment. The position and size of the gaps may change as the beam moves and/or rotates relative to the column.

Each aperture 619 has a lateral axis 698 and a longitudinal axis 696. Lateral axis is perpendicular to an extent or long axis 692 of beam 602. In the present example, each aperture is laterally elongate, perpendicular to the beam. However, the apertures are larger than the teeth as measured along both the lateral and longitudinal axes. Specifically, each aperture 619 has a lateral extent 676 and a longitudinal extent 672. Each tooth 614 is circular, so both a lateral extent 678 and a longitudinal extent 674 are equal to the diameter of the tooth. Both lateral extent 676 and longitudinal extent 672 of apertures 619 are greater than the diameter of the tooth.

Gap 622 may provide a delay in moment transfer. That is, as described above, connection 600 may not transfer moment through an initial range of rotation of the beam. In this example, moment may not be transferred until gap 622 is closed and upper beam plate 618 contacts teeth 614 of lugs 612 and/or lower beam plate 620 contacts teeth 614 of horizontal plate 616.

In FIG. 15, connection 600 is shown in an un-connected configuration. To engage the beam and column fixtures of the connection, an end portion of beam 602 may be brought adjacent to column 604, and lowered with web 654 received between shear plates 610 until plate 618 contacts lugs 612, and plate 620 contacts or approaches plate 616.

Also on horizontal plate 616 and mounted to the column face, is a latch 624. In the present example, latch 624 is a gate-latch style mechanism with a central gusset sandwiched between two rotatable latch plates. As lower beam plate 620 lowers onto horizontal plate 616 and engages lower teeth 614, the beam plate may push down on both latch plates, rotating a projecting portion out of the way. Once beam plate 620 is seated on horizontal plate 616, the latch may return to an original position in which the projecting portion blocks removal of the beam plate.

In general, any effective latch or lock mechanism may be used in place of latch 624. Such a latch may serve to retain a beam in alignment, and prevent accidental disconnection of the beam from the column. A latch may not need sufficient capacity to resist lifting of the beam by a construction crane, but may provide sufficient resistance to such lifting as to create enough deterrent or delay in disconnection of the beam to ensure safe building site conditions.

In FIG. 17, connection 600 is shown in an erection phase configuration. In this configuration, upper beam plate 618 may rest on lugs 612, with a tooth 614 extending through each aperture 619. Lower beam plate 620 may rest on horizontal plate 616 and/or proximate but spaced from the horizontal plate, also with a tooth 614 extending through each aperture 621.

In this position, the beam may be supported by lugs 612 and horizontal plate 616 prior to installation of fasteners through shear plates 610. That is, connection 600 may be described as including a standard dual-plate shear connection, and additional structures. The additional structures may provide sufficient shear resistance to support the weight of the beam.

In FIG. 16, connection 600 is shown in a service phase configuration. Fasteners 608 may be installed to provide the full shear capacity of the connection. Each fastener may be installed through a hole 611 of each shear plate 610 and a hole 857 of web 854. Shear plates 610 may be fastened to the beam web by any effective fasteners. For instance, bolts such as bolts 308 of standard shear connection 300 may be used. For instance, a threaded rod may be used with two nuts. For instance, a pin with snap-fit or retaining features such as a collet may be used.

Beam 602, column 604, and connection 600 are an example of a beam-to-column connection assembly as described above. Upper beam plate 618 and lower beam plate 620 are examples of brace structures, as described above. Teeth 614 are examples of integral pins, as described above.

C. Illustrative Y-Clip Delayed Moment Connection

As shown in FIGS. 18-20, this section describes an illustrative beam-to-column connection assembly of a steel building frame, including a column 704, a beam 702, and a connection 700. Connection 700 is an example of an erection support shear connection (ESSC) and a delayed moment connection (DMC), as described above.

A Y-clip or pair of modified shear plates 710, each having a number of vertically aligned holes 711, are mounted to column 704. At a top end, each plate turns outward, away from a centerline of the column, to form a horizontal tab 709 with an aperture 719. Each aperture 719 is fitted with a retaining ring clip 724 on an underside of the respective horizontal tab portion 709.

In the present example, column 704 is a W-flange column, and a vertical panel 707 extends between flanges of the column for mounting the column-side fixture assembly of connection 700. In some examples, the fixture may be mounted to an outer side of one of the flanges of a W-flange column. In some examples, the fixture may be mounted to one side of an HSS or box column. In general, plates and structures of an ESSC mounted on a column may be mounted in an effective manner. For example, an assembly of plates and/or braces may be welded to a web, flange, face, and/or corner of a column.

A horizontal plate 716 is mounted below shear plates 710 at a bottom edge of vertical panel 707. Horizontal plate 716 extends between the flanges of column 704 to attach to the flanges and web of the column. The horizontal plate also extends out past shear plates 710 to support a pair of sharply tapered teeth 714. In some examples, plate 716 may be mounted to the face of a flange of the column and supported by a brace.

Beam 702 is an I-beam, with a web 754 symmetrically connecting upper and lower flanges 752. The beam has a lower cut-out or cope 762, to allow the web of the beam to be received between shear plates 710 without interference from the bottom flange of the beam. Web 754 of beam 702 also includes a plurality of vertically aligned holes 757, corresponding to holes 711 of shear plates 710.

A pair of apertures 721 extend through the bottom flange of the beam, proximate lower cope 762 (see FIG. 20), corresponding to teeth 714 on horizontal plate 716. A ring clip 724 is positioned over each aperture. In the depicted example, an upper flange bar 718 is mounted to top flange 852 of beam 702. Another pair of tapered teeth 714 are mounted to the flange bar, extending downward. Such a bar may be appropriate on smaller beams, with narrower flanges. In examples of connections on larger beams, the flange bar may be omitted and teeth 714 may be mounted directly to the flange of the beam.

In the depicted example, plates 710 of connection 700 extend down to contact and are fixed to horizontal plate 716. Such connection may reduce positioning error in manufacturing of the column-side connection elements, but require more material. In some examples, plates 710 may be spaced from and not directly connected to horizontal plate 716.

Each plate 710 further includes a tapered cut-out 720 above vertically aligned holes 711. A shape of the cut-out can be seen best in FIG. 19. A correspondingly sized dowel bar 723 is fixed in the web of each beam. In some examples, a pin or dowel bar may be fixed to the column and the beam may include a cut-out. For instance, dowel bar 723 may extend through shear plates 710 below holes 711, and beam web 754 may include a cut-out tapering up from lower cope 762.

In the depicted example, cut-out 720 extends around the curve of the plate, but not into horizontal tab 709. In general, an extent of each cut-out may be determined by a lateral extent of dowel bar 723. That is, cut-outs 720 may extend sufficiently away from each other in a lateral direction to accommodate the dowel bar.

Apertures 719 and 721 are each larger than teeth 714, as best shown in FIG. 20. In the present example, teeth 714 are all of the same size, and apertures 719 match apertures 721. In some examples, the size of teeth and/or apertures may differ between the upper and lower portions of the connection.

As shown in FIG. 20, aperture 721 is elongate perpendicular an extent or long axis of the beam. However, the aperture may also be described as having a width greater than tooth 714 as measured parallel a long axis of the beam. That is, aperture 721 has an extent 772 in a direction parallel the beam and tooth 714 is circular with a diameter 774, where extent 772 of aperture 721 is greater than diameter 774 of tooth 714. This difference in size forms a gap 722 between adjacent surfaces of the tooth and aperture.

The position and size of gap 722 may change as the beam moves and/or rotates relative to the column. Gap 722 may also provide a delay in moment transfer. That is, as described above, connection 700 may not transfer moment through an initial range of rotation of the beam. In this example, moment may not be transferred until gap 722 is closed and tooth 714 contacts lower beam flange 752 (or tab 709 of shear plate 710) at the edge of aperture 721 (or 719).

In FIG. 18, connection 700 is shown in an un-connected configuration. To engage the beam and column fixtures of the connection, an end portion of beam 702 may be brought adjacent to column 704, and lowered into position. As beam 702 is lowered, beam web 754 may be received between shear plates 710, and dowel bar 723 may be received in cut-out 720 of each plate. Teeth 714 may be received into the corresponding apertures of plates 710 or beam flange 852. The tapered shapes of cut-outs 720 and teeth 714 may help to guide the beam into the correct position.

In FIG. 20, connection 700 is shown in an erection phase configuration. Once positioned, dowel bar 723 may contact a bottom of cut-out 720 in each shear clip 710. Upper flange bar 718 may rest on horizontal tabs 709 of plates 710, with a tooth 714 extending down through aperture 719 in each tab. Bottom flange 752 of beam 702 may rest on horizontal plate 716 and/or proximate but spaced from the horizontal plate, also with a tooth 714 extending up through each aperture 721 of the bottom flange of the beam. The dowel bar, upper flange, and/or lower flange of the beam may engage the shear plates and/or horizontal plate, transferring sufficient shear loads from the beam to the column to support the weight of the beam.

Where included, retaining ring clips 724 may snap-fit into a groove in each tooth 714 to hold the teeth in engagement with the plates and retain connection 700 in the erection phase configuration. The ring clips may be sufficiently yielding to allow each tooth 714 to move to any position in the respective aperture 719, 721, despite the different in shape between the ring clips and apertures.

In this configuration, the beam may be supported by plates 710 and horizontal plate 716 prior to installation of fasteners through plates 710. That is, connection 700 may be described as including a standard dual-plate shear connection, and additional structures. The additional structures may provide sufficient shear resistance to support the weight of the beam. The additional structures may also provide a desired degree of rotational stiffness past a certain degree of racking. Gaps between elements of the connection may be closed by such racking, and contact between corresponding surfaces may create the rotational stiffness.

In FIG. 22, connection 700 is shown in a service phase configuration. Fasteners 708 may be installed to provide the full shear capacity of the connection. Each fastener may be installed through a hole 711 of each shear plate 710 and a hole 757 of web 854. Shear plates 710 may be fastened to the beam web by any effective fasteners, extending through the aligned apertures.

Beam 702, column 704, and connection 700 are an example of a beam-to-column connection assembly as described above. The Y-clip of shear plates 710 with horizontal tabs 709 and horizontal plate 716 together are an example of a clip structure as described above. The vertical portion of shear plates 710 may be described as a shear connection portion of the clip structure. Horizontal tabs 709 and horizontal plate 716 may be described as a moment connection portion of the clip structure.

Upper flange bar 718 is an example of a brace structure, as described above. Lower flange 752 is an example of a flange coupled to a clip structure without a brace structure, as described above. Teeth 714 are examples of integral pins, as described above.

D. Illustrative Web Cleat Delayed Moment Connection

As shown in FIGS. 21-23, this section describes an illustrative beam-to-column connection assembly of a steel building frame, including a column 804, a beam 802, and a connection 800. Connection 800 is an example of an erection support shear connection (ESSC) and a delayed moment connection (DMC), as described above.

A pair of shear plates 810 with a number of vertically aligned holes 711 is mounted to a side face of column 804. A channel 814 is formed by a pair of channel plates 820, each one of the pair fixed to an inner surface of a corresponding one of shear plates 810. In the depicted example, channel plates are a separate plate welded to shear plates 810. In some examples, channel plates 820 may be formed with shear plates 810 as part of a single structure.

Beam 802 is an I-beam, with a web 854 extending perpendicularly between upper and lower flanges 852. The beam has a lower cut-out or cope 862, to allow the web of the beam to be received between the shear plates without interference from the bottom flange of the beam.

Web 854 of beam 802 also includes a plurality of vertically aligned holes 857, corresponding to holes 811 of shear plates 810. Fixed to each side of web 854 of the beam, over holes 857, is a cleat 812. Only one cleat is shown in FIG. 21, but a substantially identical cleat may be similarly positioned on the other side of web 854. Each cleat 812 is shaped to correspond to channel 814 between shear plates 810, as shown more clearly in FIG. 23.

Cleat 812 includes an upper tapered section and a lower tapered section, joined by a central straight section. A size of the tapered section may remain the same across beam sizes, while the central section may have a length corresponding to the beam size. Each tapered section includes an aperture 816 matching and aligned with either the uppermost or the lowermost of holes 857 in the beam web.

In the present example, the central section of cleat 812 includes a cut-out 818 over the remaining holes 857. Depending on the size of the central section and the number of apertures in the beam web, the central section may include two or more cut-outs over the remaining apertures in the beam web, or if web 854 includes only two holes 857 the cut-out may be omitted.

In FIG. 23, one of cleats 812 is depicted as received in channel 814. Only one of each of channel plates 820 and shear plates 810 is shown. Channel plate 820 may be described as generally U-shaped, or as having a central, vertically extending cutout. Channel 814 may be larger than cleat 812, forming a gap 822. Specifically, based on the position of cleat 812 in channel 814, there is a gap between an inner surface of channel plate 820 and one or both side surfaces of each of the upper and lower tapered sections of cleat 812. The position and size of the gap may change as the beam moves and/or rotates relative to the column.

Gap 822 may allow tolerance for installation, while tapering of the channel and cleat may help guide the beam into alignment. Gap 822 may also provide a delay in moment transfer. That is, as described above, connection 800 may not transfer moment through an initial range of rotation of the beam. In this example, moment may not be transferred until gap 822 is closed and cleat 812 contacts the inner surface of channel 820 distal from the column.

In the depicted example, corresponding surfaces of cleat 812 and channel plate 820 are shown as matching or parallel. In some examples, a shape of the surfaces may be selected to achieve a desired area or angle of contact under beam rotation. Gap 822 may be sized and/or shaped to delay moment transfer until a desired degree of beam rotation is reached.

In FIG. 21, connection 800 is shown in an un-connected configuration. To engage the beam and column fixtures of the connection, an end portion of beam 802 may be brought adjacent to column 804, and lowered into position. As beam 802 is lowered, beam web 854 and cleats 812 may be received in channel 814, between shear plates 810. The tapered sections of cleats 812 may help to correctly position the beam and avoiding catching or hangups, as the cleats are received into channel 814.

In FIG. 23, connection 800 is shown in an erection phase configuration. Once positioned, cleat 812 contacts a bottom of channel 814, transferring sufficient shear loads from the beam to the column to support the weight of the beam. Cleats 812 and channel 814 may be long enough to effectively retain connection 800 in the erection phase configuration.

In FIG. 22, connection 800 is shown in a service phase configuration. Once erection of the building frame, or an appropriate sub-set of the building such as a tower assembly, is complete bolts 808 may be installed to provide the full shear capacity of the connection. Each bolt may be installed through a hole 811 of each shear plate 810, hole 857 of web 854, and either hole 816 or cut-out 818 of each cleat 812.

Beam 802, column 804, and connection 800 are an example of a beam-to-column connection assembly as described above. Shear plates 810 and channel plates 820 together are an example of a clip structure as described above. Shear plates 710 may be described as a shear connection portion of the clip structure. Channel plates 820 may be described as a moment connection portion of the clip structure.

E. Illustrative Collar Flexible Moment Connection

FIGS. 24-27 show a flexible moment collar 900, which is an example of an erection support shear connection (ESSC) and a limited moment connection (LMC), as described above. Collar 900 may also be described as a combination of four ESSC's, a cooperative assembly of ESSC's, partially restrained connection, and/or a flexible moment connection.

Column 904 includes four faces and four corners. Each beam 902 is mounted proximate a corresponding face of the column. Each beam 902 includes a web 954 spanning between upper and lower beam flanges 952. The collar includes four flange assemblies 910, and four corner assemblies 912. Flange assemblies 910 and corner assemblies 912 alternate, such that each corner assembly engages two flange assemblies, and similarly each flange assembly engages two corner assemblies.

As shown in FIG. 25, each corner assembly 912 is welded to one of the corners of column 904. In the present example, each flange assembly 910 is welded to one of beams 902. In some examples, fewer than four beams may be connected to the column and up to three flange assemblies may remain un-welded to a beam.

Flange assemblies 910 and corner assemblies 912 are fastened together by horizontal pins 908 extending through corresponding holes in the assemblies. Each pin 908 extends through two flange assemblies and a corner assembly. Each corner assembly is fastened by only four pins, and collar 900 is fastened by a total of only sixteen pins.

As shown in FIG. 26, corner assembly 912 includes two feet 930. The feet extend the length of the assembly and define an interior angle at their intersection, which corresponds to the geometry of column 904. In the present example the column has a square cross-section, and the interior angle defined by feet 930 is a right angle.

Each foot 930 is configured for mounting on a face of the column, such that the corner assembly spans a corner of the column. A standoff 932 extends from the intersection of the feet, oriented generally parallel to a bisector of the interior angle. Standoff 932 also includes a perpendicular retaining structure 933, distal from feet 930. Standoff 932 and retaining structure 933 may be described as a T-shaped structure.

Four holes 936 extend through standoff 932, to receive pins 908. The holes are divided into upper and lower pairs, corresponding to the upper and lower flanges of flange assemblies 910. All four holes 936 are stacked, or vertically aligned.

In some examples, one or more of corner assemblies 912 may include a gravity stop and/or vertical alignment structure. For instance, a horizontal plate may be disposed on a bottom face of standoff 932, extending beyond the standoff in a direction generally parallel retaining structure 933.

As shown in FIG. 27, the flange assembly includes a top flange 936 and a bottom flange 938, connected by an insert 940. The top and bottom flanges may be identical, mirrored only in their position for attachment to the I-beam. Insert 940 is symmetrical about both horizontal and vertical axes. Insert 940 is attached to corresponding inner surfaces of top flange 936 and bottom flange 938 by bevel welds 942.

Each of the top and bottom flanges may be manufactured by cutting or stamping a rectangular shape out of sheet or plate metal. The ends of the rectangle may be bent to form wings 946 at left and right ends of the flange. Two holes 944 extend through each wing. Holes 944 may align with holes 934 of corner assemblies 912 to receive pins 908.

Each flange has a thickness 950. Each pair of holes 944 has a vertical spacing 953. Thickness 950 and vertical spacing 953 may each be selected to achieve appropriate moment load resistance or other structural properties of flange assembly 910, while limiting material and cost. In some examples, a length or width of the flange, and/or a horizontal spacing between holes may be similarly selected.

The insert may be manufactured by cutting or stamping sheet or plate metal. The insert is elongate, with a central elongate portion 948 and trapezoidal end portions 956 for connection to the flanges of the assembly. The insert may also be described as flaring at the ends. Such a flared shape may minimize material used by allowing weld length and insert width to be separately optimized, in order that the connection of the insert to the flanges is sufficiently strong without unnecessary strength in the insert.

The upper and lower ends of insert 940 are beveled, for welding to the flanges 936, 936. In some examples, the ends of the insert may have other shapes appropriate to other weld types and/or include other connection features. Each end has a width 955, which may also be referred to as a weld length. In the present example, weld length 955 is approximately 7 inches in order to transfer 200 kip (kilopound, 7000 pounds of force) between the insert and connected flange. Depending on the required safety margin and the anticipated loads, weld length 955 may also be 5.5 inches or 3.8 inches.

Flange assembly 910 may be sized to match a depth and weight of an I-beam. Dimensions or other properties of the flange assembly may also be tuned according to properties of the I-beam such as stiffness, and/or expected erection phase or in-service loads. For example, flange thickness 950, hole spacing 953, and weld length 955 may be varied to achieve appropriate stiffness and/or moment load capacity of flange assembly 910 while minimizing material and/or manufacturing cost.

Illustrative Combinations and Additional Examples

This section describes additional aspects and features of beam-to-column connection assemblies, presented without limitation as a series of paragraphs, some or all of which may be alphanumerically designated for clarity and efficiency. Each of these paragraphs can be combined with one or more other paragraphs, and/or with disclosure from elsewhere in this application, including the materials incorporated by reference in the Cross-References, in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing without limitation examples of some of the suitable combinations.

• • A0. A beam-to-column connection assembly for a building, comprising: a column having a fixture assembly mounted on a side face of the column, and a beam having a fixture assembly on an end portion of the beam, wherein the fixture assemblies are engaged forming a connection structure joining the column to the beam at a ninety degree angle, and wherein the connection structure provides a moment connection between the column and beam when being assembled with additional beams and columns, and provides a simple connection between the column and beam when the building is fully constructed.
  • A1. The assembly of A0, wherein the connection structure is a flexible moment connection.
  • A2. The assembly of A0 or A1, wherein the rotational stiffness of the connection structure is delayed over an initial rotational range.
  • A3. The assembly of any of A0-A2, wherein transmission of bending moment between the column and beam is delayed for an initial rotational range.
  • A4. The assembly of any of A0-A3, wherein the rotational stiffness of the connection structure is negligible over an initial rotational range, then increases after the initial rotational range.
  • A5. The assembly of A4, wherein the initial rotational range is less than about 0.5 degrees, 1 degree, 1.5 degrees, or 2 degrees.
  • A6. The assembly of any of A0-A5, wherein the rotational stiffness of the connection structure is negligible over an initial rotational range, then providing a flexible moment connection after the initial rotational range.
  • A7. The assembly of any of A0-A6, wherein the beam is an I-beam having a web portion connecting a top flange to a bottom flange, the connection structure transferring shear and rotational loads through the beam web and at least one of the flanges.
  • A8. The assembly of any of A0-A7, wherein the fixture assembly on the column includes a clip structure, the beam is an I-beam having a web portion between an upper flange portion and a lower flange portion, a first brace structure mounted on the upper flange portion, the first brace structure being coupled to the clip structure.
  • A9. The assembly of A8, wherein each of the first brace structure and the clip structure has at least one aperture, the first brace structure and clip structure being coupled via a pin extending through the apertures.
  • A10. The assembly of A8 or A9, wherein the first brace structure and clip structure are connected by a pin extending through a hole defined in the first brace structure or the clip structure.
  • A11. The assembly of A10, wherein an elongate axis of the pin is oriented horizontally.
  • A12. The assembly of A10 or A11, wherein an elongate axis of the pin is oriented at least substantially perpendicular to a long axis of the column.
  • A13. The assembly of any of A10-A12, wherein an elongate axis of the pin is oriented vertically.
  • A14. The assembly of any of A10-A13, wherein an elongate axis of the pin is oriented at least substantially parallel to a long axis of the column.
  • A15. The assembly of any of A9-A14, wherein one of the apertures is elongated along an axis parallel to a long axis of the beam.
  • A16. The assembly of any of A9-A15, wherein one of the apertures has a greater width than the pin, as measured parallel to a long axis of the beam.
  • A17. The assembly of any of A9-A16, wherein the first brace structure includes two plate members mounted on the upper flange portion, each of the plate members having an aperture for receiving a pin for locking engagement between the first brace structure and the clip structure.
  • A18. The assembly of any of A9-A17, wherein the first brace structure extends over a cope beyond an end edge of the upper flange portion.
  • A19. The assembly of any of A9-A18, a second brace structure being mounted on the lower flange portion, the second brace structure being coupled to the clip structure.
  • A20. The assembly of A19, wherein the second brace structure extends under a cope beyond an end edge of the lower flange portion.
  • A21. The assembly of any of A0-A20, wherein the column further includes an additional fixture assembly mounted on the side face of the column at a distance along a long axis of the column corresponding to a floor-to-floor spacing in the building, the additional fixture assembly being configured to engage a fixture assembly of one of the additional beams.
  • A22. The assembly of any of A0-A21, wherein the column further includes an additional side face and an additional fixture assembly mounted on the additional side face, the additional fixture assembly being configured to engage a fixture assembly of one of the additional beams.
  • A23. The assembly of any of A0-A22, wherein the beam has a second fixture assembly on an opposite end of the beam for engaging a fixture assembly on another column.
  • A24. The assembly of any of A0-A23, wherein the fixture assemblies are at least partially welded to the column and beam, respectively.
  • A25. The assembly of any of A0-A24, wherein the columns and beams form a self-supporting structure while being assembled.
  • A26. The assembly of A10, wherein the first brace structure and clip structure are connected by two or more pins extending through corresponding holes defined in the first brace structure or the clip structure.
  • A27. The assembly of A17, wherein the two plate members are angle irons.
  • A28. The assembly of A17, wherein the two plate members are planar vertical plates.
  • B0. A construction assembly, comprising: a steel beam having a first end portion including a web portion, a top flange portion, and a bottom flange portion, a column having a side face, a beam engagement structure mounted on the side face of the column, a first brace fixture mounted on an outer side of the top flange portion, and a second brace fixture mounted on an outer side of the bottom flange portion, wherein each of the first and second brace fixtures is connected to the beam engagement structure of the column, providing a moment connection between the beam and the column.
  • B1. The assembly of B0, wherein the beam engagement structure includes a clip structure configured for fastening the column to the web portion of the beam.
  • B2. The assembly of B1, wherein the clip structure has a shear connection portion and a flexible moment connection portion.
  • B3. The assembly of B1 or B2, wherein the clip structure has a shear connection portion and a delayed moment connection portion.
  • B4. The assembly of any of B1-B3, wherein each of the first and second brace fixtures has a fixture hole, the clip structure having an upper clip hole and a lower clip hole, each of the brace fixture holes being aligned with and pinned to one of the clip holes.
  • B5. The assembly of B4, wherein at least one of the fixture and clip holes is elongate parallel to a long axis of the beam.
  • B6. The assembly of B5, wherein each of the fixture holes is elongate parallel to the long axis of the beam.
  • B7. The assembly of B5 or B6, wherein each of the clip holes is elongate parallel to the long axis of the beam.
  • B8. The assembly of any of B5-B7, wherein each of the first and second brace fixtures includes a pair of angle iron members mounted on the outer side of the top flange portion, each of the angle iron members having a hole for receiving a pin, locking engagement of the brace fixture to the clip structure.
  • B9. The assembly of any of B0-B8, wherein the beam is an I-beam, H-beam, or W-flange beam.
  • C0. A construction assembly, comprising: a column having a side face, and a beam-end engagement structure mounted on the side face of the column, wherein the beam-end engagement structure has a shear connection portion configured for coupling to a web portion of an I-beam, and a moment connection portion configured for coupling to a flange portion of the I-beam.
  • C1. The construction assembly of C0, wherein the beam-end engagement structure includes a pair of clip portions mounted on the side face of the column.
  • C2. The construction assembly of C1, wherein each clip portion has an upper portion for engaging an upper flange of the beam, a lower portion for engaging a lower flange of the beam, and a middle portion for engaging a web portion of the beam.
  • D0. A construction assembly, comprising: an I-beam having a web portion between an upper flange portion and a lower flange portion, and an upper brace fixture mounted on the upper flange portion configured for coupling to a column via a pin-in-hole engagement device, providing a moment connection between the beam and the column.
  • D1. The construction assembly of D0, wherein the web portion has a series of holes for bolting to a column to provide a simple shear connection.
  • D2. The construction assembly of D0 or D1, wherein the pin-in-hole engagement device has an elongate hole providing delayed rotational restraint over an initial rotational range.
  • D3. The construction assembly of any of D0-D2, further including a lower brace fixture mounted on the lower flange portion providing the moment connection between the beam and the column.
  • D4. The construction assembly of D3, wherein the lower brace fixture is configured for coupling to the column via a pin-in-hole engagement device having an elongate hole providing delayed rotational restraint over an initial rotational range.
  • E0. A construction assembly, comprising: a column, and a beam connected to the column by a connection assembly, wherein the connection assembly allows relative rotation between the beam and the column over a first rotational range and a second rotational range, providing a simple connection over the first rotational range and a moment connection over the second rotational range.
  • E1. The assembly of E0, wherein the connection assembly provides a flexible moment connection over the second rotational range.
  • E2. The assembly of E0, wherein the connection assembly provides a full moment connection over the second rotational range.
  • F0. A tower assembly for a building, comprising: four columns, and four beams, each beam spanning two of the columns and each column being connected to two of the beams via beam-to-column connection structures, each beam-to-column connection structure providing a moment connection when the column and beam are being assembled with additional beams and columns, and providing a simple connection between the column and beam when the building is fully constructed.
  • F1. The tower assembly of F0, wherein the moment connection is delayed through an initial range of rotation between the respective beam and column.
  • F2. The tower assembly of F0 or F1, including more than four beams.
  • G0. A beam-to-column connection assembly for a building, comprising: a column having a fixture assembly mounted on a side face of the column, and a beam having a fixture assembly on an end portion of the beam, wherein the fixture assemblies are engaged forming a connection structure joining the column to the beam at a ninety degree angle, wherein the connection structure includes means for providing a moment connection when the column and beam are being assembled with additional beams and columns, and providing a simple connection between the column and beam when the building is fully constructed.
  • H0. A method of connecting a beam and column, comprising: mounting a first fixture structure on a side face of a column, mounting a second fixture structure on an end portion of a beam, erecting the column into a vertical orientation, and engaging the first and second fixture structures to form a connection structure providing a moment connection when the column and beam are being assembled with additional beams and columns, and providing a simple connection between the column and beam when a building including the column and beam is fully constructed.
  • H1. The method of H0, wherein the engaging step includes lowering the end portion of the beam into engagement with the first fixture structure.
  • H2. The method of H0 or H1, further comprising aligning holes defined in the first and second fixture structures.
  • H3. The method of H2, further comprising locking engagement of the first and second fixture structures by inserting a pin through the aligned holes.
  • H4. The method of any of H0-H3, further comprising bolting the first fixture structure to the second fixture structure.
  • J0. A beam-to-column connection assembly for a building, comprising: a column, a beam, and means for joining an end of the beam to the column at a ninety-degree angle, wherein the means provide a moment connection when the beam and column are being assembled with additional beams and columns and a simple connection between the beam and column when the building is fully constructed.
  • J1. The beam-to-column connection assembly of J0, wherein the means for joining include means for abruptly increasing a resistance to rotation of the beam relative to the column above a critical degree of rotation.
  • J2. The beam-to-column connection assembly of J1, wherein the critical degree of rotation is greater than zero degrees and less than one degree.
  • K0. A construction assembly, comprising: a column, a beam, and means for coupling the column to an end of the beam at a ninety-degree angle such that the coupling acts like a simple shear connection for small angles of rotation away from the ninety-degree angle and acts like a moment connection for larger angles of rotation away from the ninety-degree angle.
  • L0. A beam to column connection system, comprising: a collar surrounding the column, including components fixed to the column and a component fixed to a beam; wherein the collar is a partially restrained connection.
  • L1. The system of L0, wherein the collar is configured to satisfy the relationship: 2<(Ks/L)/EI<20, where Ks=Ms/θs, Ms is the moment at in-service loads, θs is the rotation at in-service loads, EI is bending rigidity of the beam, and L is the length of the beam.
  • L2. The system of L0 or L1, wherein: the component fixed to the beam is a flange assembly including an upper transverse element, a lower transverse element, and a bridging component connecting the upper and lower transverse elements, and the components fixed to the column are each a corner assembly including first and second expanses defining a corner and a T-shaped portion extending from the corner.
  • L3. The system of L2, wherein the collar includes exactly four flange assemblies and four corner assemblies, each pair of adjacent flange assemblies being fastened together through an intervening corner assembly.
  • L4. The system of L3, wherein flange assemblies fastened together are not in compression.
  • L5. The system of L3 or L4, wherein the flange assemblies are fastened together by collet pins.
  • L6. The system of any of L3-L5, wherein the flange assemblies are fastened together by snap-fit fasteners.
  • L7. The system of any of L0-L6, wherein the collar is configured to act as a fully restrained connection during an erection phase of a steel frame of a building, and to act as a simple connection during service of the building.
  • M0. A steel frame building, comprising: a plurality of columns, a plurality of beams, at least one simple connection between a one of the columns and one or more of the beams, at least one moment-resisting structure, and a self-supporting frame portion including four of the columns and four of the beams, the four columns being interconnected by the four beams, and each column being connected to two of the beams by a erection support shear connection.
  • M1. The building of M0, wherein the moment-resisting structure is a braced frame, diagonal bracing, cross bracing, or v-bracing.
  • M2. The building of M0 or M1, wherein the moment-resisting structure is a shear wall.
  • N0. A method of constructing the building of M0, including: first erecting the self-supporting frame portion, then erecting the remaining columns and beams, including the at least one simple connection, and finally installing the moment-resisting structure.
  • N1. The method of N0, wherein the installation of the moment-resisting structure is performed without use of additional supports for the columns.
  • P0. A beam-to-column connection, comprising: a column including a column-side structure; and a beam including a beam-side structure; wherein the column-side structure and the beam-side structure engage, and the engaged structures transfer shear loads from the beam to the column.
  • P1. The connection of P0, wherein the column-side structure and the beam-side structure include corresponding features which guide the beam into alignment with the column as the column-side structure and the beam-side structure are brought into engagement.
  • P2. The connection of P1, wherein the corresponding features are engaged by lowering the beam into position.
  • P3. The connection of P1 or P2, wherein the corresponding features include a tapered pin and an aperture.
  • P4. The connection of any of P1-P3, wherein the corresponding features include a horizontal post and a vertically narrowing channel.
  • P5. The connection of any of P0-P4, wherein the column-side structure and the beam-side structure include corresponding features which retain the column-side structure and the beam-side structure in engagement.
  • P6. The connection of P5, wherein the corresponding features are engaged by lowering the beam into position.
  • P7. The connection of P5 or P6, wherein the corresponding features include a latch.
  • P8. The connection of any of P5-P7, wherein the corresponding features include a snap-fit element.
  • P9. The connection of any of P0-P8, wherein the engaged structures transfer shear loads from the beam to the column without fasteners.
  • P10. The connection of P9, wherein the engaged structures permit some range of relative rotation between the beam and the column.
  • P11. The connection of P10, wherein the engaged structures limit the range of relative rotation between the beam and the column.
  • P12. The connection of any of P0-P11, further including a plurality of fasteners.
  • P13. The connection of P12, wherein the column-side structure and the beam-side structure are configured to be fastened together in a completed building frame.
  • P14. The connection of P12 or P13, wherein the column-side structure and the beam-side structure are configured to engage without fasteners during erection.
  • P15. The connection of any of P12-P14, wherein: the connected beam and column are part of a bay in a building frame, and when the column-side structure and the beam-side structure are engaged without fasteners, the connection resists lateral loads sufficiently for the bay to be self-supporting.
  • P16. The connection of any of P12-P14, wherein: the connected beam and column are part of a bay in a building frame, and when the column-side structure and the beam-side structure are engaged without fasteners, the connection resists shear loads sufficiently for the bay to be self-supporting.
  • Q0. A beam-to-column connection, comprising: a column including a column-side structure; and a beam including a beam-side structure; wherein: the column-side structure and the beam-side structure engage, and the engaged structures transfer shear loads from the beam to the column, the beam and the column have an angle of relative rotation which is zero when the beam and column are perpendicular, for angles of relative rotation between zero and an angle θ, the connection has a rotational stiffness of less than approximately (α*E*I)/L, where E is Young's modulus for the beam material, I is the area moment of inertia of the beam, and L is the length of the beam, for angles of relative rotation greater than 0, the connection has a rotational stiffness of greater than approximately α*EI/L, and a has a value between approximately 2 and 10.
  • R0. A connection between a beam and a column in a bay of a steel frame of a building, comprising: a beam-side structure; and a column-side structure, including a shear clip; wherein the connection has an erection mode in which the beam-side structure engages the column-side structure, and a service mode in which a web of the beam is bolted to the shear clip of the column-side structure; and wherein, in the erection mode, the connection allows racking in response to lateral loads through an initial range of rotation, and the connection resists lateral loads past the initial range of rotation sufficiently for the bay to be self-supporting.
  • S0. A beam-to-column connection, comprising: a column including a column-side structure having a moment-transfer surface; and a beam including a beam-side structure having a moment-transfer surface; wherein: the column-side and beam-side structures transfer shear loads from the beam to the column when engaged, the beam and the column have an angle of relative rotation which is zero when the beam and column are perpendicular; and the connection acts a shear connection for relative angles of rotation from zero through and angle α, where a is greater than an angle of relative rotation which would result from a maximum acceptable midspan deflection of the beam, and the moment-transfer surfaces of the column-side structure and the beam-side structure are in contact only for relative angles of rotation greater than a.
  • S1. The connection of S0, wherein the maximum acceptable midspan deflection of the beam is defined under a building code, regulation, or guideline.
  • S2. The connection of S0 or S1, wherein: there is an angle of relative rotation y corresponding to maximum acceptable racking of the beam and column as determined by building site safety guidelines, and a is less than or equal to y.
  • S3. The connection of S2, wherein, for relative angles of rotation greater than a, the connection has greater rotational stiffness than a shear connection.
  • S4. The connection of any of S0-S3, wherein a moment rotation curve of the connection is non-differentiable at a.
  • T0. A beam-to-column connection, comprising: a column including a column-side structure; and a beam including a beam-side structure; wherein: the column-side structure and the beam-side structure engage, and the engaged structures transfer shear loads from the beam to the column, and the beam can rotate through a first angle before significant moment is transferred from the beam through the connection to the column.
  • T1. The connection of T0, wherein significant moment is defined under a building code, regulation, or guideline.
  • T2. The connection of T1, wherein significant moment is defined in AISC specification commentary.
  • U0. A beam-to-column connection, comprising: a column including a column-side structure; and a beam including a beam-side structure; wherein: the column-side structure and the beam-side structure engage, the engaged structures transfer shear loads and some moment from the beam to the column, and zero moments are considered for the connection in a structural analysis of a building frame.

CONCLUSION

The disclosure set forth above may encompass multiple distinct examples with independent utility. Although each of these has been disclosed in its preferred form(s), the specific examples thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. To the extent that section headings are used within this disclosure, such headings are for organizational purposes only. The subject matter of the disclosure includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. Other combinations and subcombinations of features, functions, elements, and/or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.

Claims

1. A beam-to-column connection assembly for a building, comprising: a column having a fixture assembly mounted on a side face of the column, anda beam having a fixture assembly on an end portion of the beam,wherein the fixture assemblies are engaged forming a connection structure joining the column to the beam at a ninety degree angle, andwherein the connection structure provides a moment connection between the column and beam when being assembled with additional beams and columns, and provides a simple connection between the column and beam when the building is fully constructed.

2. The assembly of claim 1, wherein the connection structure is a flexible moment connection.

3. The assembly of claim 1, wherein transmission of bending moment between the column and beam is delayed for an initial rotational range.

4. The assembly of claim 1, wherein a rotational stiffness of the connection structure is negligible over an initial rotational range, then increases after the initial rotational range.

5. The assembly of claim 1, wherein the beam is an I-beam having a web portion connecting an upper flange to a lower flange, the connection structure transferring shear and rotational loads through the beam web and at least one of the flanges.

6. The assembly of claim 5, wherein the fixture assembly on the column includes a clip structure and the fixture assembly on the beam includes a first brace structure mounted on the upper flange, the first brace structure being coupled to the clip structure.

7. The assembly of claim 6, wherein each of the first brace structure and the clip structure has at least one aperture, the first brace structure and clip structure being coupled via a pin extending through the apertures.

8. The assembly of claim 7, wherein an elongate axis of the pin is oriented horizontally.

9. The assembly of claim 7, wherein one of the apertures is elongated along an axis parallel to a long axis of the beam.

10. The assembly of claim 6, wherein the first brace structure and clip structure are connected by a pin extending through a hole defined in the first brace structure or the clip structure.

11. The assembly of claim 10, wherein an elongate axis of the pin is oriented vertically.

12. The assembly of claim 10, wherein the hole has a greater width than the pin, as measured parallel to a long axis of the beam.

13. The assembly of claim 7, wherein the first brace structure includes two angle iron members mounted on the upper flange, each of the angle iron members having an aperture for receiving a pin for locking engagement between the first brace structure and the clip structure.

14. The assembly of claim 7, a second brace structure being mounted on the lower flange portion, the second brace structure being coupled to the clip structure.

15. A construction assembly, comprising a steel beam having a first end portion including a web portion, a top flange portion, and a bottom flange portion,a column having a side face, a beam engagement structure mounted on the side face of the column,a first brace fixture mounted on the top flange portion, anda second brace fixture mounted on the bottom flange portion,wherein each of the first and second brace fixtures is connected to the beam engagement structure of the column, providing a moment connection between the beam and the column.

16. The construction assembly of claim 15, wherein the beam engagement structure includes a clip structure configured for fastening the column to the web portion of the beam.

17. The assembly of claim 16, wherein the clip structure has a shear connection portion and a moment connection portion.

18. The assembly of claim 16, wherein each of the first and second brace fixtures has a fixture hole, the clip structure having an upper clip hole and a lower clip hole, each of the brace fixture holes being aligned with and pinned to one of the clip holes.

19. The assembly of claim 16, wherein each of the first and second brace fixtures includes a pair of angle iron members mounted on an upper surface of the top flange portion, each of the angle iron members having a hole for receiving a pin to lock engagement of the brace fixture to the clip structure.

20. A beam-to-column connection assembly for a building, comprising: a column having a fixture assembly mounted on a side face of the column, anda beam having a fixture assembly on an end portion of the beam,wherein the fixture assemblies are engaged forming a connection structure joining the column to the beam at a ninety degree angle, wherein the connection structure includes means for providing a moment connection when the column and beam are being assembled with additional beams and columns, and providing a simple connection between the column and beam when the building is fully constructed.