This technology relates generally to structural reinforcement. In particular, aspects of this invention relate to reinforcing round structural members of lattice structures and to reinforcing other structures.
Lattice structures such as guyed towers with a slender mast and guy wires supporting the mast horizontally, as well as self-support towers or free standing towers, are used in the telecommunications industry. In particular, such towers are used to support equipment for wireless phones, broadcast and other communications devices, among other applications.
With the proliferation of cell phones and personal communications devices comes the need for towers to support additional equipment for wireless phone, internet and other communications devices. This increase in equipment can add a significant amount of wind area to a tower or other lattice structure, which can result in an increase in axial and tensile forces to each of the tower's structural elements (tower legs, diagonals, horizontals and subsequent internal bracing). In addition, a tower's structural elements can become weaker due to the passage of time and/or due to environmental conditions.
Related art methods of increasing the strength of these structural elements in order to support additional equipment include reinforcing the weak area of the tower (generally areas under the proposed equipment elevation) by means of welding angle, split-pipe (pipe that has been cute longitudinally to create 180 degree, 120 degree) or some other variation of steel reinforcement, bar stock or flat plate. These related art structural members can be a poor fit, create large eccentric loads based on their individual section modulus proportion and in some cases only minimally increase the strength of round structural members such as tower legs. Additionally, these related art structural members are not continuous and require a significant amount of welding at their terminations to splice plates, adding the risk of fire, rusting and increased installation costs.
According to an exemplary embodiment, a method of reinforcing a round structural member of a lattice structure comprises locating a reinforcement member having at least four facets on the round structural member, wherein at least two of the at least four facets forms a point of contact with the round structural member; and securing the reinforcement member to the round structural member.
In further exemplary embodiments, a first leg and a second leg of the reinforcement member can extend beyond a centroid of the round structural member when the reinforcement member is located at the round structural member. Additionally, in further exemplary embodiments, a centroid of the reinforcement member can be within the round structural member when the reinforcement member is located on the round structural member.
In further exemplary embodiments, at least one of the points of contact is a direct point of contact between the reinforcement member and the round structural member. Additionally, in further exemplary embodiments, at least one of the points of contact is an indirect point of contact between the reinforcement member and the round structural member. In a further exemplary embodiment, the method can further comprise locating an inner tab member between the reinforcement member and the round structural member, wherein the points of contact between the reinforcement member and the round structural member are indirect points of contact via the inner tab member.
In further exemplary embodiments, first leg and a second leg of the reinforcement member can extend beyond a first leg and a second leg of the inner tab member.
In further exemplary embodiments, the reinforcement member can comprise a hot rolled plate. Also, in further exemplary embodiments, the reinforcement member comprises a cold formed plate. Also, in further exemplary embodiments, the reinforcement member can comprise an extruded shape.
In further exemplary embodiments, the method can comprise joining the reinforcement member with a second reinforcement member to extend a length of continuous reinforcement along the round structural member. The method can also comprise joining the reinforcement member and the second reinforcement member comprises joining the reinforcement member and the second reinforcement member around a splice plate of the round structural member.
According to an exemplary embodiment, a method of reinforcing a round structural member of a lattice structure comprises locating first and second reinforcement members on the round structural member, the first and second reinforcement members each comprising first and second tubular members; locating a first threaded bar within the first tubular member of the first and second reinforcement members and locating a second threaded bar within the second tubular member of the first and second reinforcement members; and securing the first threaded bar at the first and second reinforcement members using first and second threaded locking members and securing the second threaded bar at the first and second reinforcement members using third and fourth locking members.
In further exemplary embodiments, the first and second threaded bars can span a segment of the round structural member located between a first and second splice plate of the round structural member. In further exemplary embodiments, the first and second threaded bars can span a splice plate of the round structural member. Additionally, the first and second threaded bars can secure the first reinforcement member to the second reinforcement member during the installation of the first and second reinforcement members.
According to an exemplary embodiment, a reinforcement system for a round structural member of a lattice structure comprises a reinforcement member having at least four facets, wherein the reinforcement member has an open-ended cross sectional shape, the reinforcement member coupled with the round structural member such that at least two of the at least two facets forms a point of contact with the round structural member along a longitudinal span of the round structural member.
In a further exemplary embodiment, in a cross sectional view taken perpendicular to a centroid of the round structural member, a first leg and a second leg of the reinforcement member extend beyond a centroid of the round structural member.
In a further exemplary embodiment, wherein the reinforcement member is a first reinforcement member, wherein the longitudinal span is a first longitudinal span, the reinforcement system further comprises a second reinforcement member having at least four facets, wherein the second reinforcement member has an open-ended cross sectional shape, the second reinforcement member coupled with the round structural member such that each of the at least four facets forms a point of contact with the round structural member along a second longitudinal span of the round structural member; and a coupling assembly spanning the first and second reinforcement members, the coupling assembly coupled to both the first and second reinforcement members, the coupling assembly configured to permit a longitudinal distance between the first and second reinforcement members to be adjusted after the first and second reinforcement members have been coupled to the round structural member.
In a further exemplary embodiment, wherein the reinforcement member is a first reinforcement member, wherein the round structural member is a first round structural member, the reinforcement system further comprises a second reinforcement member having at least four facets, wherein the second reinforcement member has an open-ended cross sectional shape, the second reinforcement member coupled with a second round structural member such that each of the at least four facets forms a point of contact with the second round structural member along a longitudinal span of the second round structural member; a splice connection between the first and second round structural members; and a coupling assembly spanning the first and second reinforcement members, the coupling assembly coupled to both the first and second reinforcement members, the coupling assembly configured to permit a longitudinal distance between the first and second reinforcement members to be adjusted after the first reinforcement member has been coupled to the first round structural member and the second reinforcement member has been coupled to the second round structural member.
These and other aspects and embodiments of the disclosure are illustrated and described below.
Exemplary embodiments are described with reference to the following figures, which are presented for the purpose of illustration only and are not intended to be limiting.
In the Drawings:
a to 3d show cross sectional views of reinforcement members for reinforcing a round structural member according to exemplary embodiments.
a to 5d show cross sectional views of reinforcement members and internal tab members for reinforcing a round structural member according to exemplary embodiments.
a to 6c show cross sectional views illustrating methods of securing a reinforcement member to a round structural member according to exemplary embodiments.
a shows reinforcement members for reinforcing a round structural member of a lattice structure according to an exemplary embodiment and
a shows an exemplary embodiment of reinforcement members for reinforcing a round structural member of a lattice structure joined according to an exemplary embodiment and
a shows an exemplary embodiment of reinforcement members for reinforcing a round structural member of a lattice structure joined according to an exemplary embodiment and
In a further exemplary embodiment, a reinforcement system for a round structural member 1 of a lattice structure comprises a reinforcement member 2 having at least four facets 3, wherein the reinforcement member 2 has an open-ended cross sectional shape. The reinforcement member 2 is coupled with the round structural member 1 such that each of the at least four facets forms a point of contact 4 with the round structural member 1 along a longitudinal span of the round structural member. In a further exemplary embodiment, in a cross sectional view taken perpendicular to a centroid of the round structural member 1, first and second legs 5 of the reinforcement member extend beyond a centroid 6 of the round structural member 1.
In related art systems where reinforcement does not extend beyond the centroid 6 of round structural members 1, large eccentric moments can be created that require welding longitudinally to resist this coupling moment and in some cases, add a significant increase in wind loads further overstressing the structural members below. Additionally, with the offset of related art reinforcements, their corresponding splice can also become offset, requiring further welding and/or bracing to correct this issue. By contrast, in exemplary embodiments, by extending the legs 5 of the reinforcement members 2 well beyond the centroid 6 of the round structural member 1, the eccentricities can be minimized and splices can be installed radially, e.g., 180 degrees apart, through the centroid 6 of the round structural members 1.
a to 3d show cross sectional views of reinforcement members 2 for reinforcing a round structural member 1 according to exemplary embodiments. The reinforcement members 2 can, for example, be made with multiple bends such as 4-facets or 7-facets so as to fit snug on small round members or larger round members.
In exemplary embodiments, the reinforcement members 2 can, for example, be formed from a hot rolled plate or a cold formed plate. The hot rolled or cold formed plate can, for example, be made from steel through extrusion and/or by bending a plate longitudinally in a brake press. In exemplary embodiments, the extruded member can be round or sided with multiple facets. In exemplary embodiments, the hot rolled or cold formed plate can have at least three bends and four facets and can increase the number of bends to maintain a tighter fit on larger round structural members 1. The hot rolled or cold formed plate can be made from any length with any number of facets. For example, the plate can be formed from a length from 1 foot to 40 feet.
a to 5c show cross sectional views of reinforcement members 2 and internal tab members 8 for reinforcing a round structural member 1 according to exemplary embodiments. The points of contact 4 are indirect points of contact between the reinforcement member 2 and the round structural member 1. Stated differently, the reinforcement member 2 includes the inner tab member 8 which contacts the round structural member 1 at points of contact 4. In particular, the inner tab member 8 is located between the reinforcement member 2 and the round structural member 1, such that the points of contact 4 between the reinforcement member 2 and the round structural member 1 are indirect points of contact via the inner tab member 8.
a to 6c show cross-sectional views illustrating methods of securing a reinforcement member 2 to a round structural member 1 according to exemplary embodiments.
In exemplary embodiments, reinforcement members 2 can be used to strengthen round structural members 1 of various sizes. The overall length and inner diameter of the reinforcement members 2 is selected based on the geometry of the round structural member 1 being reinforced. The thickness of the reinforcement members 2 is selected based on the amount of steel area appropriate to strengthen the round structural member. The quantity and spacing of U-bolts with backing plates 10 and/or stitch welds 11 can be selected to ensure a minimum unbraced length of the reinforcement members 2 with respect to the round structural member 1. If multiple tower sections require reinforcement, the reinforcement members 2 can be spliced as illustrated in
In exemplary embodiments, U-bolts with tapered backing plates 10 can be used to pinch or compress the legs 5 of the reinforcing members 2 around the backside of the round structural member 1. Locating U-bolts with tapered backing plates 10 near tubular member 16 can help prevent reinforcing members 2 from opening up in tension or compression due the offset in load from threaded bars 17, shown below in
In exemplary embodiments, the reinforcement members 2 can span through multiple tower sections or around antenna mounts, guy attachments or any other obstruction.
In an exemplary embodiment, the threaded bars 17 can secure the reinforcement members 2 together during the installation of the reinforcement members 2 by tightening the threaded bolts 18. As such, the reinforcement members 2 can be joined to provide continuous reinforcement without waiting for the structure to settle. Adjustment of the distance separating the upper reinforcement member 2 from the lower reinforcement member 2 may be achieved by loosening or tightening the nuts 18; this may be performed in real time as the reinforcement members 2 are being installed. This saves time and cost over traditional welded solutions, and also permits the aforementioned distance separating the two reinforcement members 2 to be adjusted at a later time, which saves time and cost over traditional “bolt-in-place” solutions for spanning two sections of a member or a splice between two members. This adjustment in the distance between the lower reinforcement member 2 and the upper reinforcement member 2 may also permit a customized or selected amount of tensional force on the round structural member 1 to be applied at the time of installation and/or at a later time.
In a further exemplary embodiment, reinforcement member 2 is a first reinforcement member 2, and the longitudinal span of the round structural member 1 is a first longitudinal span. The reinforcement system further comprises a second reinforcement member 2 having at least four facets 3, wherein the second reinforcement member 2 has an open-ended cross sectional shape. The second reinforcement member 2 is coupled with the round structural member 1 such that each of the at least four facets 3 forms a point of contact 4 with the round structural member 1 along a second longitudinal span of the round structural member 1. A coupling assembly 20 spanning the first and second reinforcement members is coupled to both the first and second reinforcement members 2. The coupling assembly is configured to permit a longitudinal distance between the first and second reinforcement members 2 to be adjusted after the first and second reinforcement members 2 have been coupled to the round structural member 1.
In a further exemplary embodiment, where the reinforcement member 2 is a first reinforcement member and the round structural member 1 is a first round structural member, the reinforcement system further comprises a second reinforcement member 2 having at least four facets 3. The second reinforcement member 2 has an open-ended cross sectional shape and the second reinforcement member 2 is coupled with a second round structural member 1 such that each of the at least four facets 3 forms a point of contact with the second round structural member 1 along a longitudinal span of the second round structural member 1. The reinforcement system further comprises a splice connection between the first and second round structural members 1. Additionally, the reinforcement system comprises a coupling assembly 20 spanning the first and second reinforcement members 1. The coupling assembly is coupled to both the first and second reinforcement members 2, and the coupling assembly is configured to permit a longitudinal distance between the first and second reinforcement members 2 to be adjusted after the first reinforcement member 2 has been coupled to the first round structural member 1 and the second reinforcement member 2 has been coupled to the second round structural member 1.
Additionally, in an exemplary embodiment, by “jacking” the splice apart, the coupling assembly 20 will create upward and downward forces on the existing flange plates (e.g., vertical flange plate 13 and/or horizontal flange plate 14), and in turn, remove axial loads or residual stresses from the existing tower leg such as round structural member 1. These residual stresses will be transferred to the new leg reinforcement member 2 allowing both the existing and new leg reinforcement members 2 to work compositely, sharing any new axial or tension forces from the addition of antennas, mounts and other equipment and transmission lines added to a tower.
It will be appreciated that while a particular sequence of steps has been shown and described for purposes of explanation, the sequence may be varied in certain respects, or the steps may be combined, while still obtaining the desired configuration. Additionally, modifications to the disclosed embodiment and the invention as claimed are possible and within the scope of this disclosed invention.
The present application claims the benefit of U.S. Patent Application No. 62/045,310, filed on Sep. 3, 2014, the content of which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | |
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62045310 | Sep 2014 | US |