Patent Issued for Gusset Plate Connection of Beam to Column

By a News Reporter-Staff News Editor at Journal of Engineering -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Tran, Andy Thao (Irvine, CA); Houghton, David L. (Laguna Hills, CA); Adams, Jared J (Mission Veijo, CA); Karns, Jesse (Mission Veijo, CA), filed on November 27, 2013, was published online on July 28, 2015.

The assignee for this patent, patent number 9091065, is Columbia Insurance Company (Omaha, NE).

Reporters obtained the following quote from the background information supplied by the inventors: "It has been found in a moment-resisting building having a structural steel framework, that most of the energy of an earthquake, or other extreme loading condition, is absorbed and dissipated, in or near the beam-to-column joints of the building.

"In the structural steel construction of moment-resisting buildings, towers, and similar structures, most commonly in the past, the flanges of beams were welded to the face of columns by full-penetration, single bevel, groove welds. Thus, the joint connection was comprised of highly-restrained welds connecting a beam between successive columns. Vertical loads, that is, the weight of the floors and loads superimposed on the floors, were and still are assumed by many to be carried by vertical shear tabs or pairs of vertical, structural angle irons arranged back-to-back, bolted or welded to the web of the beam and bolted or welded to the face of the column.

"The greater part of the vertical load placed upon a beam was commonly assumed to be carried by a shear tab bolted or welded to the web of the beam and bolted or welded to the face of the flange of the column at each end of the beam. Through the use of face-to-face gusset plates welded to the column, the greater part of the vertical load is carried by the gusset plates.

"Experience has shown that the practice of welding the beam's flanges directly to the column is uncertain and/or unsuitable for resistance to earthquakes, explosions, tornadoes and other disastrous events. Such connection means and welding practice has resulted in sudden, fractured welds, the pulling of divots from the face of the column flange, cracks in the column flange and column web, and various other failures. Such highly-restrained welds do not provide a reliable mechanism for dissipation of earthquake energy, or other large forces, and can lead to brittle fracture of the weld and the column, particularly the flange of the column and the web of the column in the locality of the beam-to-column joint, (known as the 'panel zone').

"It is desirable to achieve greater strength, ductility and joint rotational capacity in beam-to-column connections in order to make buildings less vulnerable to disastrous events. Greater connection strength, ductility and joint rotational capacity are particularly desirable in resisting sizeable moments in both the lateral and the vertical plane. That is, the beam-to-column moment-resisting connections in a steel frame building can be subjected to large rotational demands in the vertical plane due to interstory lateral building drift. Engineering analysis, design and full-scale specimen testing have determined that prior steel frame connection techniques can be substantially improved by strengthening the beam-to-column connection in a way which better resists and withstands the sizeable beam-to-column, joint rotations which are placed upon the beam and the column. That is, the beam-to-column connection must be a strong and ductile, moment-resisting connection.

"Reference is made to co-assigned U.S. Pat. Nos. 5,660,017, 6,138,427, 6,516,583, and 8,205,408 (Houghton et al.) for further discussion of prior practice and the improvement of the structural connection between beams and columns through the use of gusset plates. These patents illustrate the improvements that have been manifested commercially in the construction industry by Houghton and others in side plate technology. Initially, side plate construction was introduced to greatly improve the quality of the beam-to-column connection. Further improvements included the provision of side plate technology using full length beams to achieve greater economy and to facilitate more conventional erection techniques."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "In one aspect, a joint connection structure of a building framework generally comprises a column assembly including a column and a pair of gusset plates connected to the column on opposite sides of the column and extending laterally outward from the column. A full-length beam assembly includes a full-length beam having upper and lower flanges and an end portion received between the gusset plates. A connecting member is operatively attached by welding to at least one of said flanges of the full-length beam. The connecting member is bolted to at least one of the gusset plates of the column assembly to connect the full-length beam assembly to the column assembly.

"In another aspect, a prefabricated column assembly generally comprises a column. A pair of gusset plates are connected to the column on opposite sides of the column and extend laterally outward from the column. A connecting member is welded to an outer surface of at least one of the gusset plates. Bolt holes are associated with the gusset plates and connecting member for receiving bolts to connect the prefabricated column assembly to a prefabricated beam assembly generally between the pair of gusset plates during erection of a building framework.

"In still another aspect, a prefabricated column assembly generally comprises a column. Gusset plates are connected to the column on opposite sides of the column and extend laterally outward from the column. A connecting member is attached to one of the gusset plates. A first plurality of bolt holes are disposed in the connecting member and a second plurality of bolt holes are disposed in said one gusset plate. Each of the first bolt holes has a bolt receiving axis extending generally along a length of the column and each of the second bolt holes has a bolt receiving axis extending transverse to the length of the column. The bolt holes are configured to connect the prefabricated column assembly to a beam assembly.

"In yet another aspect, a prefabricated full-length beam assembly generally comprises a full-length beam including top and bottom flanges. Slotted bolt holes are associated with at least one of the top and bottom flanges of the full-length beam for receiving bolts positioned to connect the prefabricated full-length beam assembly to gusset plates of a prefabricated column assembly during erection of a building framework. The slotted bolt holes are slotted generally perpendicular to a longitudinal axis of the full-length beam such that a dimension of each bolt hole extending generally perpendicular to the longitudinal axis of the full-length beam is greater than a dimension of each bolt hole extending parallel to the longitudinal axis of the full-length beam. The prefabricated full-length beam assembly is free of connection to a column prior to erection of the building framework.

"In still yet another aspect, a joint connection structure of a building framework generally comprises a column assembly including a column and a pair of gusset plates connected to the column on opposite sides of the column and extending laterally outward from the column. A beam assembly includes a beam having upper and lower flanges and an end portion received between the gusset plates. A first plurality of bolts connects the upper flange of the beam to the column assembly and a second plurality of bolts connects the lower flange of the beam to the column assembly. Each of the first bolts have a bolt receiving axis extending transverse to a length of the beam member and generally along a length of the column and each of the second bolts have a bolt receiving axis extending transverse to the length of the beam and transverse to the length of the column.

"In yet still another aspect, a joint connection structure of a building framework generally comprises a column assembly including a column and a gusset plate assembly including a pair of gusset plates connected to the column on opposite sides of the column and extending laterally outward from the column. A full-length beam assembly includes a full-length beam having an end portion. A connecting member is operatively attached by welding to an axially facing end of the full-length beam. The connecting member is bolted to the gusset plate assembly of the column assembly to connect the full-length beam assembly to the column assembly.

"In another aspect, a prefabricated column assembly generally comprises a column. A pair of gusset plates extend laterally outward from the column. Bolts attach the gusset plates to the column on opposite sides of the column."

For more information, see this patent: Tran, Andy Thao; Houghton, David L.; Adams, Jared J; Karns, Jesse. Gusset Plate Connection of Beam to Column. U.S. Patent Number 9091065, filed November 27, 2013, and published online on July 28, 2015. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=9091065.PN.&OS=PN/9091065RS=PN/9091065

Keywords for this news article include: Technology, Legal Issues.

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