Patent Application
20250116105
The present invention relates to a moment frame connector system designed to connect a beam to a column in constructions, and in particular to a high strength moment frame connector system effective in resisting high winds and other lateral loads.
Lateral loads due to natural phenomena such as high winds can have devastating effects on the structural integrity of buildings, bridges and other constructions. Lateral forces generated during such natural phenomena may cause the top portion of a wall to move laterally with respect to the bottom portion of the wall, which movement can result in damage or structural failure of the wall and, in some instances, collapse of the building. One of the critical components in the structural framework of buildings is the connection between beams and columns. In conventional construction, this connection is achieved through various methods such as welding, bolting, or adhesive bonding. While these methods are effective in moderate conditions, they often fall short in high wind areas, where the large forces acting on the structure can lead to joint failure, compromising the structural integrity of the entire building. The stiffness of these connections are also important to the behavior of the lateral system and in protecting architectural components.
One method of providing a high-strength connection effective at resisting lateral loads is to increase the size of the beam; that is, to increase the height of the web section between the upper and lower flanges. However, increasing the size of beams is problematic as the vertical space available for such beams is at a premium, and structural engineers designing such constructions would prefer to work with standard sized beams and columns.
It is also known to provide T-shaped connectors including vertical sections affixed to the column and horizontal sections affixed to the top and bottom flanges of the beam.
Another consideration unrelated to loading of structures is the ease and effectiveness with which such structures may be erected by crews at a worksite. One task which adds to the time, complexity and cost of constructions is having to weld components together at the worksite. Bolted connections are typically preferred, in that they may be accomplished more quickly, effectively and without the additional equipment and labor costs associated with welding.
The present technology relates to a high strength moment frame connector system which operates with beams and columns of standard dimensions. The moment frame connector system includes a shear tab connected between the column and beam, and a pair of T-shaped connectors connected between the column and beam. Each T-shaped connector, referred to herein as a T-plate, includes a vertical section affixed to the column and a horizontal section affixed to upper and lower flanges of the beam. In accordance with aspects of the present technology, the vertical and/or horizontal sections of each T-plate may be made long and thick to withstand high winds and other large lateral loads. In order to allow the vertical section of each T-plate to be made long and thick without impinging on the space used for the shear tab, a notch may be provided within the vertical sections of one or both T-plates. The bolts connecting the beam to the column are also important to the strength and stiffness of the connection. In order to fit larger bolts to a T-plate connection, the vertical sections would need to be long and thick. The notches in accordance with the present technology also allow for the use of larger bolts, without impinging on the space used for the shear tab.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.
The present technology will now be described with reference to the figures, which in embodiments relate to a high strength moment frame connection system which works with beams and columns of standard dimensions. In embodiments, the moment frame includes a beam having a central web affixed to top and bottom flanges, and a column having a central web affixed to inner and outer flanges. The moment frame connector includes a shear tab affixed to the inner flange of the column as by welding, and to the central web of the beam as by bolts. The moment frame connector further includes a pair of T-shaped connectors, referred to herein as T-plates, each having a vertical plate integrally formed or otherwise connected to a horizontal plate. An upper T-plate has its vertical plate affixed to the inner flange of the column as by bolts, and has its horizontal plate affixed to the upper flange of the beam as by bolts. A lower T-plate has its vertical plate affixed to the inner flange of the column as by bolts, and has its horizontal plate affixed to the lower flange of the beam as by bolts.
In certain applications, it is desirable to increase the strength of the moment frame connector by increasing the size of the shear tab. T-plates and/or the bolts for those components. In accordance with the present technology, this may be accomplished by forming a notch in the vertical plates of the upper and lower T-plates. This allows the size of the shear tab, T-plates and/or bolts to be increased without interfering with the position of the shear tab. These notches also allow different T-plates to be used as needed for a particular project, while working with standard beams, columns and shear tabs.
It is understood that the present technology may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the technology to those skilled in the art. Indeed, the technology is intended to cover alternatives, modifications and equivalents of these embodiments, which are included within the scope and spirit of the technology as defined by the appended claims. Furthermore, in the following detailed description of the present technology, numerous specific details are set forth in order to provide a thorough understanding of the present technology. However, it will be clear to those of ordinary skill in the art that the present technology may be practiced without such specific details.
The terms “top” and “bottom,” “upper” and “lower” and “vertical” and “horizontal,” and forms thereof, as may be used herein are by way of example and illustrative purposes only, and are not meant to limit the description of the technology inasmuch as the referenced item can be exchanged in position and orientation. Also, as used herein, the terms “substantially” and/or “about” mean that the specified dimension or parameter may be varied within an acceptable manufacturing tolerance for a given application. In one embodiment, the acceptable manufacturing tolerance is ±0.15 mm, or alternatively, ±2.5% of a given dimension.
For purposes of this disclosure, a connection may be a direct connection or an indirect connection (e.g., via one or more other parts). In some cases, when a first element is referred to as being connected, affixed, mounted or coupled to a second element, the first and second elements may be directly connected, affixed, mounted or coupled to each other or indirectly connected, affixed, mounted or coupled to each other. When a first element is referred to as being directly connected, affixed, mounted or coupled to a second element, then there are no intervening elements between the first and second elements (other than possibly an adhesive or melted metal used to connect, affix, mount or couple the first and second elements).
In one example, each of the webs 102a, 104a of the beam and column may have a thickness of 1 inch, ¾ inch or ½ inch, though the thicknesses of the webs 102a. 104a may vary in further embodiments and need not be the same as each other. In one example, each of the flanges 102b, 102c. 104b, 104c of the beam and column may have a thickness of 1 inch, though the thicknesses of the flanges may vary in further embodiments and need not be the same as each other. Embodiments herein describe the column and beam as having an I-shaped cross-section. However, in further embodiments, at least the column may be hollow structural sections (HSS) tube steel with a square, rectangular or circular cross-section. Moreover, in embodiments, the column 102 and beam 104 are both monolithic structures. However, in further embodiments, the column 102 and/or beam 104 may be built up of discrete sections that are bolted, welded or otherwise affixed to each other.
The moment frame connector system 100 includes top and bottom T-plates 106 and a shear tab 108. The T-plates 106 are explained hereinafter. Shear tab 108 may be shipped to the construction site welded to inner flange 102b of column 102. Once at the construction site, the shear tab 108 may be bolted to the web 104a of beam 104. The shear tab 108 may be affixed to the column 102 and/or beam 104 by other methods in further embodiments. The dimensions of the shear tab 108 may vary, but in one example, the shear tab may have a length (between the flanges of the beam 104) of 10 inches to 18 inches, a width of 5 inches to 14 inches, and a thickness of ½ inch to 1 inch. Each of these dimensions may vary in further embodiments. The illustrated examples include three bolts to affix the shear tab 108 to the web 104a of beam 104, but there may be other numbers of bolts in further embodiments.
The top and bottom T-plates 106 will now be described with respect to the various views of
In embodiments, the vertical and horizontal plates 106a. 106b may be formed integrally with each other, and may for example be cut from a single section of I-beam or W-beam. The vertical and horizontal plates 106a, 106b may be formed separately and affixed to each other as by welding in further embodiments. The vertical plate 106a may be affixed to inner flange 102b of column 102, as for example by bolts fitting through bolt holes 112. The horizontal plate 106b of the top T-plate 106 may be affixed to the upper flange 104b of beam 104, as for example by bolts fitting through bolt holes 114. The horizontal plate 106b of the bottom T-plate 106 may be affixed to the lower flange 104c of beam 104, as for example by bolts fitting through bolt holes 114. Assembly of the T-plates 106 between the column 102 and beam 104 is explained in greater detail below with respect to
In accordance with aspects of the present technology, a notch 110 may be formed in the vertical plates 106a of the top and bottom T-plates 106. The notch 110 may be centered in the vertical plate 106a (left to right from the perspective of
In embodiments, the sections of the vertical plate 106a extending above and below the horizontal plate are of equal length. However, in further embodiments, it is possible that one of these sections be longer than the other. In such embodiments, the notch 110 may be formed in the longer section or the shorter section.
As seen for example in
Thereafter, as shown in
Thereafter, as shown in
It has been determined through finite element analysis (FEA) that the notches 110 may be formed in the vertical plates 106a of the T-plates 106 without sacrificing the strength or thickness of the T-plates 106.
The length and width of the notches 110 may vary depending at least in part on the dimensions of the T-plates 106, shear tab 108 and nut and bolt fasteners 120. In one example, the T-plate 106 may have a width of 8 inches, and the vertical plate 106a may extend 4 inches above and below the horizontal plate 106b. The bolt holes 112 in the vertical plate 106a in this example may be centered across the width of the T-plate and spaced apart from each other 5 inches. In this example, the notch 110 may have a width (between the bolt holes 112) of 2 inches and a height of 2 inches. It is understood that these dimensions are by of example only and may vary in further embodiments, proportionately and disproportionately to the dimensions of the vertical plate 106a of T-plate 106.
The T-plates 106 having the notches 110 according to embodiments of the present technology provide a few advantages. For example, the notches 110 allow T-plates 106 with vertical plates 106a that are thick and/or long, shear tabs 108 which are thick and/long and nut and bolt fasteners 120 of large diameter, all of which without interference between the T-plate, shear tab and nut and bolt fasteners. Enlarging some or all of these components allows the moment frame connector system of the present technology to be sufficiently strong and stiff to be used in constructions in high wind areas or for structures otherwise requiring strong resistance to large lateral loads. This may also be accomplished using standard sized columns and beams.
Another advantage of the present technology is that the notches 110 allow a variety of different sized components (including the T-plates 106, shear tabs 108 and/or nut and bolt fasteners 120) to be used with standard sized columns and beams so that the moment frame connector 100 may be adapted for use in a variety of different lateral load scenarios.
A further advantage of the present technology is that the notches 110 allow a single size T-plate to be used with different sizes and types of shear tabs 108 and/or nut and bolt fasteners 120, based for example on varied lateral load requirements of the moment frame connector. This increases the flexibility of the structural engineer when designing a moment frame connector for different lateral loads. Another example is that the notches act as guides when assembling the beam 104 to the column 106, thereby making assembly quicker and easier at the construction site.
In addition to allowing for longer, thicker T-plates and/or shear tabs, the notches also allow for larger nut and bolt fasteners 120 to be used. With typical moment connectors, the diameter of bolt used to connect each of the upper and lower connectors to the column is limited by the space required for shear tab connections. This in turn limits the capacity that can be achieved for a particular beam depth. The notches 110 allow for larger diameter bolts to be used in the connection without intruding on the space needed to attach the shear tab 108 to the column 102. Higher capacities and stiffnesses can therefore be achieved using the present technology. This also eliminates the need to cope the beam which can be costly and labor intensive.
In embodiments described above, the T-plates have a constant cross-sectional width making them strong and stiff, and ideal to resist yielding in the lateral loads encountered in high wind areas. In further embodiments, the T-plates may alternatively be provided with a mechanical fuse designed to yield to provide hysteretic damping in the lateral loads encountered in seismic activity areas. Such an embodiment will now be described with reference to the hysteretic damping T-plate 126 shown in the perspective view of
The vertical plates 126a and horizontal plates 126b of T-plates 126 may be affixed to the column 102 and beam 104 using nut and bolt fasteners 120 as described above. As is known, buckling restraint plates 130 may be bolted to the upper and lower flanges 104b, 104c of beam 104 using nut and bolt fasteners 132 to sandwich the horizontal plates 126b between the buckling restraint plates and the beam flanges. The hysteretic damping T-plates 126 may be used in any of the embodiments described above and below with respect to T-plates 106.
The edge views of
As noted above, the notches 110 may be shaped to receive a variety of different shear tabs 108.
In embodiments described above, the T-plates 106 are bolted to the column 102 and beam 104. As noted, this provides advantages in minimizing welding in the field. However, it is understood that the T-plates 106 may be welded to the column and/or beam in further embodiments.
In
In
In summary, embodiments of the present technology relate to a structural connector for a moment frame, comprising: a shear tab configured to mount to a first portion of the moment frame; a first plate configured to mount to a second portion of the moment frame; a second plate configured to mount to a third portion of the moment frame, the second plate extending from a portion of the first plate to divide the first plate into a first section and a second section; and a notch formed in the first or second sections of the first plate, the notch configured to receive an edge of the shear tab.
In another example, embodiments of the present technology relate to a structural connector for a moment frame including a column and a beam, the structural connector comprising: a shear tab configured to mount to the column and the beam; a first plate configured to mount to the column; bolt fasteners configured to mount the first plate to the column; a second plate configured to mount to the beam, the second plate extending from a portion of the first plate to divide the first plate into a first section and a second section; and a notch formed in the first or second sections of the first plate, the notch configured to prevent interference between one or more of the shear tab, the first plate and the bolt fasteners.
In a further example, embodiments of the present technology relate to a moment frame, comprising: a column; a beam comprising an upper flange and a lower flange; a structural connector configured to attach the beam to the column, the structural connector comprising: a shear tab configured to mount to the column and the beam; a first plate mounted to the column above the shear tab; a second plate mounted to the upper flange of the beam, the second plate extending from a portion of the first plate to divide the first plate into a first section and a second section, the first section facing downward toward the shear tab; and a notch formed in the first section of the first plate, the notch configured to prevent interference between the first plate and the shear tab.
The foregoing detailed description of the technology has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the technology to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the technology and its practical application to thereby enable others skilled in the art to best utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the technology be defined by the claims appended hereto.
