The present invention relates to making and installing pre-fabricated assemblies of threaded bars for intimate contact with aggregate structural material, such as concrete.
The present invention relates to building construction technologies. In particular, the present invention relates to the fabrication and installation of reinforcing bars for members of concrete structures, such as columns and walls, among other things. The present invention provides a method and apparatus for the safe, efficient and economical pre-fabrication and erection of assemblies of reinforcing bars used in the construction of concrete structures.
In multi-level concrete construction, it is a common practice to place longitudinal steel reinforcement rods individually. Pre-fabrication of assemblies of longitudinal reinforcing bars is sometimes employed to limit the on-site labor associated with the placement of individual bars. These assemblies generally utilize wire ties or other common bar ties to form an assembly, or module, of typically four or more reinforcing bars. Such assemblies are also often provided with some or all of the transverse reinforcement installed.
Recent advances in concrete reinforcement technology have led to the increased use of threaded reinforcing bars. So-called threadbar reinforcement has continuous thread-like deformations along the length of the bar, and are typically provided with compatible hardware with complimentary internal threading, such as nuts, couplers, anchors, etc. Threadbar reinforcement has been used for many decades and is available from domestic and international suppliers such as Dywidag Systems International, Williams Form Engineering and SAS Stressteel, to name a few.
Threaded reinforcing bars are typically connected with internally threaded couplers. Coupling of the bars generally requires rotating, or spinning, of the couplers along the bars, as well as rotating, or torquing, one or both of the so connected bars for full engagement of the coupler. This requires that one or both of the threaded bars being connected be free to rotate. The use of conventional prefabricated cages, or modules, is generally not suited for this purpose, because in creating a rigid cage for installation, the free rotation of the bars is typically impeded. This represents a significant disadvantage of conventional prefabrication techniques. Another disadvantage of conventional pre-fabricated reinforcement cages is that during their installation the rigging is attached to the permanent cage at the top, thus requiring a worker to climb up the cage to release the hoisting leads.
Alternatively, the prior art patents of Ferrer (U.S. Pat. No. 8,375,678) and Ferrer (U.S. Pat. No. 8,381,479) teach a method and apparatus for the prefabrication of modular reinforcement cages for concrete structures, wherein longitudinal threaded reinforcing bars are held in formation by a set of flat, two dimensional templates with apertures cut at the location and corresponding diameter to the reinforcing bars that are subsequently charged through the apertures. The flat planar templates of Ferrer '678 and Ferrer '479 are provided perpendicular to the axis of the reinforced bars, impeding aggregate material concrete flow therethrough. The apertures are provided with enough clearance from the reinforcing bars to permit free movement of the bars with respect to the template. The reinforcing bars are then locked in place against the template by use of opposing internally threaded lock nuts. Standard set screws are then installed into the lock nuts to provide a temporary locking mechanism to prevent inadvertent rotation, or spinning, of lock nuts during fabrication, transportation and erection. Such locking mechanisms must obviously be removed in order to rotate the bars. The use of internally threaded lock nuts is intended to permit the free rotation of the threaded reinforcing bars through the template and lock nuts, thus allowing the bars to be rotated in the field during installation. The flat, two dimensional templates of Ferrer '678 and Ferrer '479 are intended to provide accurate spatial relation of the longitudinal bars, as well as rigidity for the module when being lifted.
Although the prior art patents of Ferrer '678 and Ferrer '479 are intended to overcome one of the primary disadvantages of conventional pre-fabricated reinforcement cages, they possess certain additional shortcoming and disadvantages, including, but not necessarily limited to:
There is a need for a safe, efficient and economical means of fabricating and erecting reinforcement assemblies using threaded reinforcing bars that overcomes the limitations, shortcomings and disadvantages of the prior art. The present invention overcomes these limitations, shortcomings and disadvantages.
Other objects will become apparent from the following description of the present invention.
In keeping with these objects and others which may become apparent, the three dimensional (3D) prefabricated assemblies of threaded bars of the present invention are provided for intimate contact with poured concrete or other aggregate material, wherein the reinforced bars are held in place by cage frames with axially extending frame plates having axially extending threaded sleeves, with minimal interference with the concrete poured from above.
The pre-fabricated reinforcement cages of the present invention are constructed of at least two cage frames spaced apart from each other holding a plurality of longitudinally extending, axially parallel, reinforcing bars over which concrete aggregate material is poured in intimate contact. The cage frames are preferably made of axially extending steel plates and aligned extending longitudinal internally threaded sleeves which extend axially parallel to the parallel axes of the respective reinforcing bars. Preferably the internally threaded sleeves have an internal threading pattern that is complimentary to the external threading pattern of the horizontally or vertically extending longitudinal reinforcing bars. The cage frames are also optionally provided with a means for installing a lifting apparatus, such as lifting bar guide collars, to lift the prefabricated three dimensional assemblies in place prior to pouring of concrete aggregate material in intimate contact with the reinforced bars.
The locations of the internal threading along the longitudinal axis of the internally threaded sleeves are preferably aligned with those of adjacent internally threaded sleeves, to minimize binding between the reinforcing bars and the sleeves during installation of the reinforcing bars into the sleeves.
While the cage frames are preferably a plurality of axially extending plates forming a rectangle, it is known to those skilled in the art that the axially extending plates may have other geometric configurations, such as having circular, oval, square or other polygonal crossectional shapes. In the case of cylindrical or oval shaped cage frames, at least one axially aligned plate forms a complete circle or oval in crossection, wherein said at least one circular or oval plate of said cage frames extends parallel to the axes of the plurality of reinforcing bars. In the case of rectangular, square or polygonal shaped cage frames, there are a plurality of axially aligned plates connected edgewise to each other by common joints, forming square, rectangular or other polygonal shaped cage frames, wherein said plates of said cage frames extend parallel to the axes of the plurality of reinforcing bars.
The longitudinal reinforcing bars have continuous thread-like deformations along their exterior length, so that they can be installed into the internally threaded sleeves during the fabrication.
For definition purposes, in connection with the words “axially extending” with respect to the directional positioning of the cage frame plates of the cage frame, the term “axially extending” means “vertically extending” if the axis of the reinforcing bars is vertical in installation before pouring of concrete. Likewise, the term “axially extending” means “horizontally extending” if the axis of the reinforcing bars are horizontal in installation before pouring of concrete.
Each three dimensional cage frame functions as a rigid structural frame defining the dimensions of the pre-fabricated reinforcement cage and the locations of the longitudinal reinforcing bars, while providing great strength and rigidity to the pre-fabricated reinforcement cage. The dimensions of the pre-fabricated reinforcement cage and the quantity and locations and of the internally threaded sleeves and longitudinal reinforcing bars is determined by design. The spatial geometry of the cage frame, the thickness of cage frame plates and internally threaded sleeves, as well as the welds and fasteners, as the case may be, are also determined by design, based upon the weight of the pre-fabricated reinforcement cage and the transportation and erection forces, among other things.
Preferably, where the pre-fabricated reinforcement cage is installed in a vertical, or substantially vertical, orientation, the pre-fabricated reinforcement cage is provided with lifting apparatus, such as at least one, and preferably two, lifting bars inserted through the lifting bar guide collars on the cage frame. The lifting bars are comprised preferably of steel bars with external threading at one end to accept a fastener, such as a nut having complimentary internal threading. The nut is preferably provided with a temporary holding means comprised preferably of a spring clamp, but alternatively may be provided with a standard set screw. The opposite end of the lifting bar is provided with a preferably cylindrical steel lifting collar onto which a preferably steel lifting ring, or hook eye, is attached, either directly or with the use of sleeves and bearing plates, to prevent movement of the lifting bars.
The aforementioned lifting apparatus may be adapted for use with other prefabricated bar assemblies, such as conventionally used bar cages and that of Ferrer '678 and Ferrer '479.
Reinforcement members, such as beam stirrups, column ties and wall ties are installed around erection wires for pre-fabrication of the reinforcement cages.
The pre-fabricated reinforcement cage may be constructed in a shop or at the site by first assembling the three dimensional cage frames and setting them into position with the use of gigs, bracing and other fabrication aids utilized in common practice.
The longitudinal reinforcing bars are installed with mechanical rotating tools into the thus assembled three dimensional cage frames, preferably by rotating the bars through the respective internally threaded sleeves of the three dimensional cage frames to the desired position along the length of the pre-fabricated reinforcement cage.
At any time before, during or after installation of the longitudinal reinforcing bars to their intended position in the pre-fabricated reinforcement cage, the lifting bars are installed through the lifting bar guide collars to their intended position in the pre-fabricated reinforcement cage, and fastened in place, preferably with temporary holding means such as clamps, to prevent movement of the lifting bar through the lifting bar collar.
After the longitudinal reinforcing bars are installed to their intended position in the pre-fabricated reinforcement cage, temporary holding means, such as a spring clamp, may be installed on opposite sides of the internally threaded sleeves to prevent unintended rotation of the longitudinal reinforcing bars (3) relative to the threaded sleeves.
After the pre-fabricated reinforcement cage(s) are constructed, they are transported to the construction site. Where the pre-fabricated reinforcement cage will be installed in a vertical or substantially vertical orientation, the hoisting rigging is attached to the lifting collars of the lifting bars. For horizontal, or substantially horizontal applications, the pre-fabricated reinforcement cage(s) can be rigged in a typical manner. The pre-fabricated reinforcement cage(s) are then lifted to their intended locations and in alignment with any adjacent reinforcement to which it is intended to be connected. Prior to making such connection, any temporary holding means installed during the fabrication are to be removed, thus allowing the longitudinal reinforcing bars to rotate freely within the internally threaded sleeves. The longitudinal reinforcing bars may then be connected, or coupled, together my typical methods. Once a sufficient number of longitudinal reinforcing bar connections have been made to ensure that the pre-fabricated reinforcement cage is stable, the lifting bars are free to be extracted from the pre-fabricated reinforcement cage and reused for subsequent or future pre-fabricated reinforcement cages.
The internally threaded sleeves may be cylindrical or alternatively be of polygonal shape, such as hexagonal for example, and may be provided integral, or may be split sleeves. They can be welded directly to the cage frame plates or may be connected to the cage frame plates by first welding the internally threaded sleeves to steel flange plates and then bolting the thus prepared sleeve assembly to the cage frame plates with standard threaded fasteners. Optional flanged nuts prevent unintentional rotation of flanged nuts with respect to the lifting bar. It is also noted that the threaded sleeves may be placed over and rotated over the externally threaded reinforcing bars, or the threaded reinforcing bars may be rotated into the threaded sleeves, and then welded or otherwise fastened to the axially aligned cage frame plates.
In an alternative embodiment, smooth bore sleeves may be used in place of the internally threaded sleeves, and holding means such as locking nuts threaded onto the reinforcing bars are secured against the smooth bore sleeves thereby holding the cage frame in a fixed position along the length of the pre-fabricated reinforcement cage, while still allowing the longitudinal reinforcing bar to rotate within the smooth bore sleeve.
In another alternative embodiment, internally threaded sleeves and smooth bore sleeves with holding means such as locking nuts are used in combination.
The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which:
FIGS. 6A and 6A1 are sectional views of alternate shapes of the internally threaded sleeves of the prefabricated reinforcement cage.
FIGS. 6B and 6B1 are sectional views of alternate embodiments for the attachment of the internally threaded sleeves of the prefabricated reinforcement cage to the cage frame.
FIGS. 6C and 6C1 are sectional views of alternate embodiments for split sleeve embodiments for the internally threaded sleeves.
For illustrative purposes only, a preferred mode for carrying out the invention is described herein, wherein the following reference numerals are non-limiting examples.
The subject of the present invention will now be described, with reference to the accompanying drawings shown in
Referring to
The cage frame plates (7), internally threaded sleeves (9) and lifting bar guide collars (15) are fastened together, preferably by welding as shown by weld (7a) in
Each cage frame (5) functions as a rigid structural frame defining the dimensions of the pre-fabricated reinforcement cage (1) and the locations of the longitudinal reinforcing bars (3), while providing great strength and rigidity to the pre-fabricated reinforcement cage (1). The dimensions of the pre-fabricated reinforcement cage (1) and the quantity and locations and of the internally threaded, axially extending sleeves (9) and longitudinal reinforcing bars (3) is determined by design. The spatial geometry of the three dimensional cage frame (5), the thickness of the axially extending cage frame plates (7) and axially extending internally threaded sleeves (9), as well as the welds and fasteners, as the case may be, are also determined by design, based upon the weight of the pre-fabricated reinforcement cage and the transportation and erection forces, among other things.
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The aforementioned lifting apparatus may be adapted for use with other prefabricated bar assemblies, such as conventionally used bar cages and that of Ferrer '678 and Ferrer '479.
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The longitudinal reinforcing bars (3) are installed into the thus assembled cage frames preferably by rotating the bars through the respective axially aligned, internally threaded, axially extending sleeves (9) of the cage frames (5) to the desired position along the length of the pre-fabricated reinforcement cage (1). Mechanical rotating tools are preferably used to facilitate the installation. Such rotating tools are commonly used in the construction industry, for example to spin or rotate pipes. The rotating tools can be applied along the side of the bars as shown in
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The foregoing description of one or more embodiments of the present invention has been presented for the purposes of illustration and description. While the foregoing detailed description of the invention enables one of ordinary skill to make and use the invention, those skilled in the art will understand and appreciate the existence of variations, modifications, combinations and equivalents of the specific embodiments and methods presented. It is understood that changes in the specific embodiments and methods shown and described may be made within the scope of the description without departing from the spirit of the invention. For example, the pre-fabricated reinforcement cage of the present may be used in any application utilizing threaded rod materials, and is not limited to concrete reinforcement applications. As another example, the cage frame plates of the present invention may be combined with an open lattice type framework, such as shown in
This application is based upon provisional patent application 61/930,461 filed Jan. 22, 2014, provisional patent application 61/992,254 filed May 13, 2014 and provisional patent application 62/066,945 filed Oct. 22, 2014, and claims priority under 35 USC §119 (e) therefrom. These applications are incorporated by reference herein.
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62066945 | Oct 2014 | US |