1. Field of the Invention
The present invention is directed to composite column and beam framing members for use in building construction. More particularly, the present invention is directed to a composite column or beam and a method for its manufacture that has superior insulating and fire/heat resistance characteristics.
2. Reference to Related Art
It is well known that the steel beams and columns that are used as the structural framework of modem buildings are not fireproof. Indeed, when exposed to heat and fire, steel beams and columns will expand, warp and rapidly lose strength. To protect against this type of extreme structural damage as well as the ongoing effects of weather, modem building codes often require that a coating of protective material be applied to the exterior surface of a building's steel framework. These protective materials are typically classified as either fire-resistant materials (i.e. mineral wool, fiberglass or the like) or heat sink materials (e.g. gypsum board or cement plasters). However, additional types of thermal or weather insulation may also be thought of as protective materials. Either class of fire-protective material can, for a reasonable period of time (e.g., one to three hours), be designed to delay the heat from a fire from affecting the steel framework.
Reinforced concrete framing systems, either pour-in-place or precast/prefabricated systems, do offer some known advantages over steel framing systems in the area of fire protection. However, columns and beams constructed of reinforced concrete have the notable disadvantage of being larger and heavier than steel framing members with the same capacity. Additionally, reinforced concrete systems necessarily require the builder to use concrete forms as part of the construction process. The erection, installation and removal of those forms can add significant cost (in time and labor) to any construction project.
Composite beam and column framing members that combine steel and concrete represent a compromise between pure steel or concrete building framing systems and are known in the art. One example is U.S. Pat. No. 4,333,285, which discloses a concrete column encased in a unitary steel tube. The column is adapted to support a reinforced concrete beam that is sheathed in a steel shell.
U.S. Pat. No. 4,409,764 discusses the use of steel column and beam forms that include internal metal reinforcing skeletons. The forms are prepared at an off-site factory and subsequently erected at the building site. The steel forms are filled with concrete at the building site and remain in place as a permanent part of the building framework.
Finally, U.S. Pat. No. 5,678,375 discusses a building framework that includes a number of structural steel members that each has a hollow interior. The steel members have openings that permit the hollow interiors to be filled with concrete in conjunction with the construction of the building frame.
Composite columns and beams are generally stronger than concrete framing members of similar size and are lighter than steel framing members. However, composite framing members still suffer from an increased risk of damage as a result of exposure to heat and flame. Therefore, it would be beneficial to provide improved composite column and beam framing members that have superior insulating, thermal and/or fire resistance characteristics.
The present invention is directed to a composite column or beam framing member for use in building construction and a method of manufacturing the column or beam. Preferably, the composite framing member includes a pair of elongated shell members that have a length dimension that is greater than a width dimension. Each shell has one substantially open side that extends along the length of the shell and provides access to an interior channel that is defined by the walls of the shell. The shells are securable to each other along their open sides such that the interior channels of the shells cooperate to define a structural member having an interior volume.
Prior to being secured together, reinforcing bars are positioned throughout the interior channel as required by the user. Spacers or risers may also be positioned along the surface of the interior channel in order to maintain the reinforcing bars a predetermined distance from the interior surface of the channel. Additionally, the interior channel of at least one of the shell members may be coated with protective materials (i.e., insulation). The use of a protective material is most preferred when at least a portion of framing members of the present invention are exposed to the exterior of a building. Under such conditions, the use of a protective material on the internal surface(s) of the framing member (particularly those having exposed external surfaces) provides the framing member with an additional defense against condensation, corrosion, fire and heat.
Preferably, the composite structural member is erected (in the case of a column) or positioned (in the case of a beam) at the work site and filled with concrete according to the needs or requirements of the user.
A preferred method for constructing the composite framing members of the present invention includes a first step of providing a first and a second shell member. Each shell is elongated so as to have a length dimension that is greater than a width dimension and includes one substantially open side extending along the length dimension. The shells are preferably U- or L-shaped such that the walls of each shell define an interior channel.
In a second step, at least one spacing bar (e.g., a steel reinforcing rod) is secured along the interior surface of each shell.
In a third step, a protective material (i.e., thermal/weather insulation) is applied into the interior channel of at least one of the shells following the insertion of the at least one spacing bar into the interior channel of each shell.
In a fourth step, the first and second shells are secured together at least partially along their respective substantially open sides so that the interior channels of the first and second shell members cooperate to define either a hollow column or open beam having an interior volume.
In a fifth step, at least one reinforcing member is installed within the interior volume formed by the shells.
In a sixth step, the interior volume of the column or beam is filled with a filler material (e.g., concrete).
Therefore, the framing members of the present invention include reinforced concrete columns and beams surrounded by steel shells. The shells impart greater structural strength and integrity than the reinforced concrete columns and beams could alone. Furthermore, the concrete core of the framing member, which is aided by the use of a coating of protective material, functions as a heat sink, absorbing heat and allowing the entire framing member a longer structural life than it would have if the steel or concrete were used alone.
The invention will now be described in more detail with reference being made to the accompanying drawings in which:
Referring now to
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Following installation of the spacing bars 27, a coating of protective material 26 is applied to the surface 37 of the interior channel 36 of at least one of the shells 16, 18. The use of a protective material is most preferred when at least a portion of framing members of the present invention are exposed to the exterior of a building. Under such conditions, the use of a protective material on the internal surface(s) of the framing member (particularly those having exposed external surfaces) provides the framing member with an additional defense against condensation, corrosion, fire and heat.
Preferably, the protective material 26 is a known insulation material, such as weather insulation, a fire-resistant material (e.g., mineral wool or fiberglass), a heat sink material (e.g., gypsum board or cement plasters) or other type of thermal insulation material. Notably, coating the surface 37 of the interior channel 36 of at least one of the shells 16, 18 with the protective material 26 during the fabrication of the column 12 removes or limits the need to apply insulation to the column 12 in the field and provides the column 12 with superior insulative or fire/heat resistance characteristics.
Still referring to
Referring now to
Welding of the shells 20, 22 provides an elongated beam 14 framing member having a generally U-shaped appearance having an open interior defining an interior volume 62 that is accessible though an open side 64. Following erection of the beam 14 at a construction site, the interior volume 62 of the beam 14 may be disposed with reinforcing members 24 and then filled with a filler material 23 (as discussed above) that provides increased structural characteristics to the beam 14.
Referring now to
At least one spacing bar 27 is secured to the surface 79 of the base 70 of each shell 20′, 22′. Alternatively, spacers 40 are provided along the surface 79 of at least one shell 20′, 22′ to support the span of the at least one reinforcing member 24 from one shell 20′ to the other shell 22′. Following insertion of the spacing bars 27, a coating of protective material 26 (as discussed above) is applied to the interior surface of at least one of the shells 20′, 22′. The shells 20′, 22′ of the beam 14′ are then preferably secured by welding together the flanges 76 of the sidewalls 74 of the shells 20′, 22′.
Welding of the shells 20′, 22′ provides an elongated beam 14′ framing member having a generally U-shaped appearance having an open interior defining an interior volume 82 that is accessible though an open side 84. Following erection of the beam 14′ at a construction site, the interior volume 82 of the beam 14′ may be disposed with reinforcing members 24 and then filled with a filler material 23 (as discussed above) that provides increased structural characteristics to the beam 14′.
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In a second step 94, at least one spacing bar 27 (e.g., a steel reinforcing rod) is positioned and secured to the interior surface of at least one of the shell members.
In a third step 96, a protective material is applied into the interior channel of each shell. As discussed above, the protective material 26 is preferably a known insulation material, such as weather insulation material, a fire-resistant material (e.g., mineral wool or fiberglass), a heat sink material (e.g., gypsum board or cement plasters) or other type of thermal insulation material.
In a fourth step 98, the first and second shells are secured together at least partially along their respective substantially open sides so that the interior channels of the first and second shell members cooperate to define a hollow column or open beam having an interior volume.
In a fifth step 100, the interior volume of the column or beam is disposed with at least one reinforcing member 24.
In a final step 102, the interior volume of the column or beam is filled with a filler material (e.g., concrete).
Therefore, by the present invention there is provided composite column and beam frame members for use in building structures that combine the characteristics of steel and reinforced concrete with superior fire-resistant qualities. However, having discussed several embodiments of the present invention, various modifications thereof will be apparent to those skilled in the art and, accordingly, the scope of the present invention should be defined only by the appended claims and equivalents thereof.
This application claims priority of U.S. Provisional Patent Application 60/225,337 filed Aug. 15, 2000, and is incorporated herein by reference.
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Number | Date | Country | |
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20020026764 A1 | Mar 2002 | US |
Number | Date | Country | |
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60225337 | Aug 2000 | US |