STRUCTURAL TOWER SUPPORT LEG

TECHNICAL FIELD

[001] The present invention relates generally to structural tower support legs and, more particularly, to an apparatus and method for strengthening a tower support leg without requiring welding in the field.

BACKGROUND ART

[002] Structural steel lattice towers are widely used in the communications industry and in other technology areas. Towers of this type are generally guyed or self-supporting and include three or four round or angular legs with a structural lattice spanning between the legs. From time to time remedial operations may become necessary on the tower legs to increase the load capacity or to repair damage resulting from corrosion, for example.

[003] Current methods for strengthening or reinforcing a steel structural tower leg to increase the load capacity or repair a damaged area generally involve increasing the cross- sectional area of one or more of the legs by welding split pipe to the existing legs in the field. Field welding is undesirable for several reasons. First, safety becomes an issue since welding creates a risk of fire. Second, field welding adds significant cost to a project by requiring additional labor and inspection by a third party. As such, current methods and apparatus for strengthening existing tower legs are both time consuming and involve significant costs.

[004] A need remains for an improved apparatus and method for strengthening the structural capacity of existing steel tower legs without requiring welding in the field.

SUMMARY OF THE INVENTION

[005] This summary is provided merely to introduce certain concepts and not to identify any key or essential features of the claimed subject matter. The present invention provides an improved apparatus and method designed to take both horizontal and vertical loads for reinforcing or strengthening an existing guyed or self-supporting steel tower leg. An apparatus of the invention provides easy adjustments to the length of the apparatus without requiring welding in the field, which substantially reduces costs, eliminates fire hazards, and avoids the need for additional inspections in the field.

[006] In one embodiment, the invention provides an apparatus for reinforcing one or more leg sections of an existing steel tower, the apparatus designed to carry vertical and horizontal loads through the existing structure, and comprising a plurality of split pipe sections, one or more transition stiffeners for interconnecting the split pipe sections and allowing easy length adjustments in the field. An apparatus of the invention also includes a plurality of fasteners including mechanical fasteners and optionally an adhesive for securing the split pipe sections to an existing steel tower leg.

[007] In another embodiment, the invention provides an apparatus for reinforcing one or more support leg sections of an existing steel tower, the apparatus comprising a plurality of split pipe sections, one or more transition stiffeners for interconnecting the split pipe sections, and a plurality of U-bolt connections and optionally an adhesive for mounting the split pipe sections to an existing steel tower leg wherein the transition stiffeners are threaded rod stiffeners.

[008] In another embodiment, the invention provides an apparatus for reinforcing one or more support leg sections of an existing steel tower, the apparatus comprising a plurality of split pipe sections, a plurality of flange stiffeners, one or more transition stiffeners for interconnecting the split pipe sections, and a plurality of U-bolt connectors and optionally an adhesive for mounting the split pipe sections to an existing steel tower leg wherein the transition stiffeners are plate stiffeners.

[009] In another embodiment, the invention provides an apparatus for reinforcing one or more support leg sections of an existing steel tower designed to carry vertical and horizontal loads through the existing structure, the apparatus comprising a plurality of split pipe sections, one or more transition stiffeners for interconnecting the split pipe sections, and a plurality of U-bolt connections and optionally an adhesive for mounting the split pipe sections to an existing steel tower leg further comprising one or more flange bypass stiffeners.

[010] In another embodiment, the invention relates to a method for strengthening or reinforcing one or more support legs or sections thereof on an existing guyed or self- supporting steel lattice tower designed to carry vertical and horizontal loads through the existing structure, the method comprising the steps of: 1) cutting a split pipe into two or more sections, 2) welding a plurality of flange stiffeners and/or flange bypass stiffeners onto a first end of the split pipe, 3) welding one or more transition stiffeners onto a second end of each split pipe section(s), 4) coupling the split pipe sections by engaging the transition stiffeners on each split pipe section, and 5) securing the coupled split pipe sections to the existing tower leg needing to be strengthened using a plurality of mechanical fasteners and optionally an adhesive wherein the apparatus is secured to the tower leg without requiring welding in the field.

[Oil] In another embodiment, the invention relates to a tower leg strengthened by a process of the present invention.

[012] These and other features of the invention will become apparent from the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[013] Fig. 1A provides a front view of a section of a steel lattice tower having an embodiment of a single split pipe assembly apparatus of the invention secured to a leg portion of the tower.

[014] Fig. IB provides a front view of a section of a steel tower with another embodiment of an apparatus of the invention, a multiple split pipe assembly, secured to a leg portion of the tower.

[015] Fig. 1 C shows the embodiment depicted in Fig. IB with the apparatus separated from the tower leg portion.

[016] Fig. 2A shows a perspective view of an embodiment of a flange stiffener of an apparatus of the invention.

[017] Fig. 2B shows a side view of a portion of a section of half split pipe of an apparatus of the invention having flange stiffeners welded at one end of the half split pipe section and resting against the surface of a leg flange.

[018] Fig. 3A provides an exploded view of a portion of an apparatus of the invention depicting a flange bypass component.

[019] Fig. 3B shows the embodiment of Fig. 3 A after assembly of the flange bypass component.

[020] Fig. 4A provides a perspective view of an embodiment of a plate stiffener of the invention.

[021] Fig. 4B shows two half pipe sections having the plate stiffener shown in Fig. 4A welded to the ends thereof.

[022] Fig. 4C shows assembly of the two half pipe sections of Fig. 4B after the plate stiffeners have been aligned and bolted.

[023] Fig. 5 provides a partial perspective view of an embodiment of an apparatus of the invention including a threaded rod transition stiffener for coupling the ends of two half pipe sections. [024] Fig. 6 shows a perspective view of an embodiment of an apparatus of the invention having angle pipe sections coupled by multiple threaded rod transition stiffeners.

[025] Fig. 7 provides an enlarged view of the indicated portion in Fig. 6.

[026] Fig. 8 shows a perspective view of an embodiment of a single split pipe assembly apparatus of the invention prior to being secured to a tower leg displaying regions on the underside of the apparatus and outer surface of the tower leg to which adhesive is applied.

DETAILED DESCRIPTION OF THE INVENTION

[027] This present application claims priority to U.S. Provisional Patent Application No. 62/481,897, filed on April 5, 2017, the disclosure of which is incorporated herein by reference.

[028] While the following description details preferred embodiments of the invention, and other aspects thereof, it is to be understood that the invention is not limited to the details of construction and arrangement of the parts illustrated in the accompanying drawings and description, since the invention is capable of other embodiments, and of being practiced in various ways. In each of the figures depicted in the description, like numerals are used to refer to the same or similar parts.

[029] As used herein, the term "close proximity" is used as a relative term to indicate that two components are located near each other, for example, but without intending limitation within about one inch to about 12 inches; or from about 2 inches to about 8 inches.

[030] As used herein, the term "split pipe assembly" refers to an embodiment of an apparatus of the present invention that may refer to a single split pipe assembly or a multiple split pipe assembly.

[031] As used herein, the term "single split pipe assembly" refers to an embodiment of an apparatus of the invention which is adaptable to span a region between two flange joints on an existing tower leg to reinforce or strengthen the leg. A "single split pipe assembly" preferably includes two or more half split pipe sections of equal or unequal length that are joined by one or more transition stiffeners.

[032] As used herein, the term "multiple split pipe assembly" refers to at least two single split pipe assemblies joined end-to-end by a flange bypass stiffener mounted between each coupled single split pipe assembly. Unlike a single split pipe assembly, a multiple split pipe assembly allows an apparatus of the invention to span a section of a tower leg in excess of two adjacent or consecutive flange joints up to the entire length of a leg. [033] As used herein the term "pipe" includes round, rectangular, square, angle, or other shaped steel or other metal pipe commonly used in constructing support legs of guyed or self- supporting communication towers.

[034] As used herein the term "split pipe" refers to round pipe, or alternatively other shaped pipe that has been cut in half along a longitudinal axis. Split pipe may be cut crosswise into sections of any length desired, for example, halves, thirds, quarters, etc.

[035] As used herein, the term "half split pipe" refers to split pipe that has been cut in half crosswise to produce two equal half-length segments from the original split pipe section.

[036] As used herein the term "transition stiffener" refers to an aspect of an apparatus of the present invention that allows two or more sections of split pipe to be joined to form a single or multiple split pipe assembly. One or more transition stiffeners, for example, from one to six, are generally welded onto the ends of split pipe sections that are to be coupled.

Preferably, a transition stiffener is a threaded rod or a plate transition stiffener.

Advantageously, a transition stiffener allows easy adjustments to be made to the length of an apparatus in the field without welding.

[037] As used herein, the term "flange bypass stiffener" refers to a special type of transition stiffener which allows two or more single split pipe assemblies to be coupled through an existing flange joint on a tower leg.

[038] In one aspect, the invention provides an apparatus for reinforcing or strengthening an existing steel tower leg by securing thereto a single split pipe assembly or multiple split pipe assembly, to the section of leg needing to be strengthened without requiring welding in the field. The invention can be applied to any type of guyed or self-supporting tower having three or more round pipe or angle legs to reinforce or strengthen a tower leg. The apparatus is designed to carry vertical and horizontal loads through the existing tower structural system.

[039] In one aspect, split pipe sections of an apparatus of the invention include a plurality of flange stiffeners attached at one end for contacting the upper and/or lower surface of a flange on the tower leg. When multiple split pipe assemblies are needed to strengthen a tower leg, that is, when the tower leg section to be strengthened extends beyond two adjacent flange joints, the apparatus includes a flange bypass stiffener that allows two or more single split pipe assemblies to be coupled through a flange joint.

[040] In another aspect, an apparatus of the invention includes one or more threaded rod or plate transition stiffeners that are attached to an end of half pipe sections to be coupled together. All steps involving welding of components when fabricating an apparatus of the invention are carried out in a metal fabrication shop. An apparatus of the invention is secured to an existing tower leg by means of a plurality of mechanical fasteners, such as U-bolt connectors, and optionally an adhesive, preferably epoxy, applied between the tower leg and both end regions of the half pipe section of the apparatus.

[041] Referring now to the Figures, Fig. 1 A shows a section of a typical lattice steel tower 10 known in the art depicting portions of two support legs 20 on one face of the tower. Tower 10 includes horizontal 14 and angled 16 support cross members. Leg sections 20 include a plurality of intervaled flange joints 32 at which adjacent flanges 28 contact each other. An embodiment of an apparatus 40 of the invention is depicted after being secured to one leg section 20 to strengthen the leg. Apparatus 40 includes a single split pipe assembly 46 that spans between two flange joints 32. Single split pipe assembly 46 includes two half split pipe sections 42 each having a plurality of flange stiffeners 56 welded to one end of each half split pipe section 42. As depicted, the flange stiffeners 56 abut against the surfaces of two flanges 28 when the apparatus is secured on leg 20. Apparatus 40 further includes a plate transition stiffener 62 by which the two half split pipe sections 42 are coupled end-to-end in

longitudinally close proximity. A plurality of U-bolt connectors 68 and optionally an adhesive are provided for securing apparatus 40 to leg 20.

[042] Figs. IB and 1C show another embodiment of an apparatus 40 of the invention which provides a multiple split pipe assembly 48. Fig. IB shows apparatus 40 secured to tower leg 20 while Fig. 1C shows apparatus 40 displaced from the tower leg 20. In this embodiment, a multiple split pipe assembly spans three consecutive flange joints 32 on tower leg 20. The multiple split pipe assembly depicted in this embodiment includes two single split pipe assemblies 46 each of which includes two half split pipe sections 42 coupled by threaded rod transition stiffeners 82, 86 and 90 (best viewed in Figs. 5-7, discussed below). The two single split pipe assemblies 46 are joined via a flange bypass transition stiffener 60 which allows continuous transition of the apparatus through the middle intervening flange joint 32 along the section of the leg being strengthened. It should be understood that a multiple split pipe assembly of an apparatus of the invention is not limited to two coupled single split pipe assemblies (as illustrated in Figs. IB and 1C), but rather can include any number of coupled single split pipe assemblies as necessary to span any segment or the entirety of a tower leg.

[043] Figs. 2A-2B depict an additional aspect of an apparatus of the invention, namely a flange stiffener 56 having a notch 58 at one end to accommodate welds 30 at existing flanges. Flange stiffener 56 includes a top surface or edge 52, a bottom surface or edge 54 and flange end 59 which is adaptable to rest against or in close proximity to the top or bottom surface of a flange 28 on a tower leg 20. As depicted in Fig. 2B, a plurality of flange stiffeners 56, from two to six, are welded to one end of a half split pipe 42 such that the longitudinal axis of the flange stiffeners is parallel with the longitudinal axis of the half split pipe 42. Top surface 52 on flange stiffener 56 extends out to or near outer perimeter edge 34 of flange 28. Flange end 59 extends beyond end 43 of half split pipe 42 with vertical face 57 of notch 58 being approximately flush with end 43. In a preferred embodiment, three flange stiffeners 56 are distributed approximately evenly around the end of half split pipe 42 (only two flange stiffeners are visible in Fig. 2B). Flange stiffener 56 can have any desired shape and dimensions commensurate with the requirements of the leg and flanges to which the apparatus is to be applied; preferably a flange stiffener has a generally rectangular shape.

[044] With reference now to Figs. 3A and 3B, another aspect of an apparatus of the invention enables single or multiple split pipe assemblies to be coupled through an existing flange joint by providing a flange bypass stiffener assembly. Also depicted are a plurality of U-bolt connectors 68, plates 72, and lock nuts 70 by which an apparatus can be secured to a tower leg. A flange bypass stiffener assembly includes flange bypass stiffener 60 having a plurality of bolt holes 64. A flange bypass stiffener 60 is welded to each end of two half split pipe sections 42 to be coupled. In the embodiment depicted, a flange bypass stiffener 60 replaces one of the flange stiffeners 56 on each half split pipe section that is to be coupled, with the flange bypass stiffener 60 being welded along the central longitudinal axis of the split pipe sections, and with flange stiffeners 56 on either side of the flange bypass stiffeners.

[045] To assemble an apparatus of the invention through a flange j oint, the flange bypass stiffeners on two half split pipe sections 42 are aligned end-to-end, and two bypass stiffener plates 100 are positioned on both sides of the aligned flange bypass stiffeners in order to couple the half pipe sections across the flange joint. Bypass stiffener plate 100 includes a plurality of bolt holes 104 that align with bolt holes 64 on the flange bypass stiffeners, and bolts 102 for securing the two flange bypass stiffeners together.

[046] Unlike flange stiffeners 56, which have a height that preferably terminates at or near the outer perimeter edge 34 of a flange, the height of a flange bypass stiffener 60 extends beyond the flange outer perimeter edge 34 which allows adjacent flange bypass stiffeners 60 on both sides of a flange joint to be coupled by bolting with the two bypass stiffener plates 100 on each side of the adjoining flange bypass stiffeners. Bypass stiffener plate 100 preferably has a length that corresponds to the distance between the outer ends 61 of adjacent flange bypass stiffeners 60, and a height corresponding to the height of the flange bypass stiffener 60 less the distance to the outer perimeter edge 34 on flange 28 (Fig. 3B). [047] In another aspect, an apparatus of the invention includes one or more transition stiffeners for coupling two half split pipe sections. Generally, one or more transition stiffeners are welded to the ends that are to be coupled. A transition stiffener may be welded along the longitudinal center line of the half split pipe sections, or at any angle up to 90° in either direction from the center line. After coupling the split pipe sections with a transition stiffener, a coupling gap of about 2 to 6 inches remains between the coupled ends; preferably the coupling gap is from about 4 to 6 inches. A transition stiffener allows easy adjustments to be made to the length of an apparatus in the field, a distinct advantage when inaccuracies in measurement might otherwise complicate and delay installation of the apparatus on a tower leg.

[048] Referring now to Figs. 4A - 4C, in another aspect an embodiment of an apparatus of the invention provides a plate transition stiffener 62. Plate transition stiffener 62 includes two back-to-back half sections 62a and 62b, each of which is welded to an end of two half split pipe sections 42 that are to be coupled. Plate transition stiffener 62 can have any shape, preferably a U-shape, such that a portion of the stiffener extends beyond the end of a half split pipe section 42 to which it is welded. Half sections 62a and 62b are overlapped and bolted together to couple the half split pipe sections 42 such that a coupling gap 80 of about 2 to 6 inches remains therebetween. In the preferred embodiment, a plate transition stiffener 62 has an elongated central region 65 defining outwardly depending legs 67 on each end and arch 75 beneath central region 65, with holes 63 on each end for receiving bolts 66. When assembled, arch 75 spans coupling gap 80 between the two coupled half split pipe sections. Preferably, one of depending legs 67 on each plate transition stiffener 62 is welded to one end of each half split pipe section such that the other depending leg extends away from that end (Fig. 4B). The non-welded end of one half section of the plate transition stiffener is aligned with the welded end of the other half section, and the two plate transition half sections are bolted together thereby coupling the two half split pipe sections. While a single plate transition stiffener is depicted, with mounting along the central axis of half split pipe sections 42, it should be understood that the invention contemplates attaching more than one plate transition stiffener, for example, from two to six, and also placement of the one or more plate transition stiffeners at positions around the end of half split pipe 42 other than the center axis line.

[049] Referring now to Fig. 5, in another embodiment, a transition stiffener of an apparatus of the invention includes a threaded rod transition stiffener 78 for coupling two half split pipe sections 42. While Fig. 5 depicts a single threaded rod stiffener, it should be understood that the invention contemplates use of more than one threaded rod stiffener to couple half split pipe sections, for example, from two to six to achieve the desired structural effect for the apparatus. Preferably, there are from one to four threaded rod transition stiffeners used for coupling two pipe sections. A threaded rod transition stiffener 78 includes a threaded rod mounting plate 92, welded at its bottom edge 93 to each end of the two half split pipe sections 42 to be coupled. As depicted, mounting plate 92 is welded along the longitudinal central axis of the half pipe sections, but it should be understood that the invention contemplates placement of the mounting plate off the center line, for example, at any position up to 90°, clockwise or counter-clockwise, from the center line position. A threaded rod transition stiffener tube 90 is welded to the top edge 94 of each mounting plate 92, and a threaded rod 82 is passed through each tube 90, with locking nuts 86 and washers 84 included at each end of the rod stiffener tubes 90 for adjusting the separation between the half split pipe sections. After coupling two half split pipe sections 42 with a threaded rod transition stiffener, a gap 80 of about 2 to 6 inches, preferably about 4 to 6 inches, remains between the ends of the coupled pipe sections. The threaded rod transition stiffener is adaptable for adjusting the length of the apparatus by twisting the lock nuts to urge the ends of the apparatus against the flange surfaces.

[050] Figs. 6-7 illustrate another embodiment of an apparatus of the invention having a plurality of threaded rod transition stiffeners 78 welded to angle pipe half sections 44 for application to angle support legs. In this embodiment, a threaded rod transition stiffener 78 is welded on each face of the angle pipe near one end. Each threaded rod transition stiffener 78 includes mounting plates 92, threaded rod 82, tubes 90, locking nuts 86, and washers 84. Also included with this embodiment is a plurality, preferably four, flange stiffeners 56 welded to the ends opposite the transition stiffeners, with two flange stiffeners on each face of the angle.

[051] Another aspect of an apparatus of the invention relates to securing the apparatus to a tower leg. For this purpose, mechanical fasteners and an optional adhesive are provided. Referring now to Fig. 8, depicted is a single split pipe assembly 46 and a section of tower leg 20. In this aspect, a plurality of suitable mechanical fasteners, known to the skilled artisan, are distributed along the length of half split pipe sections 42. In the preferred embodiment, a plurality of U-bolt connectors 68 are used for securing the apparatus to a tower leg. Securing an apparatus of the invention to a tower leg may optionally also include application of an adhesive 108. If an adhesive is applied, an epoxy adhesive is preferred with application to the inner surface of a split pipe assembly covering a region approximately 12 inches to 18 inches in from the flange stiffener ends 43, and with application to a corresponding region on the tower leg surface adjacent to a flange, or as directed by an engineer. Any suitable epoxy known to the skilled artisan can be used for this purpose including, for example, DP420 (3M Company) or equivalent.

[052] An apparatus of the invention and component parts thereof can have any dimensions necessary to achieve the desired structural enhancement to accommodate the particular dimensions of a tower leg to be strengthened. The half pipe sections should have an inner diameter that corresponds with the outer diameter of the section of tower leg to be strengthened. In addition, the length of half pipe used in fabricating an apparatus of the invention will generally correspond to the length of the leg section to be strengthened less the amount of the coupling gap between coupled pipe sections of a single split pipe assembly, and/or the gap introduced by flange bypass stiffeners in a multiple split pipe assembly. Any suitable material can be used to fabricate the component parts of the apparatus including metal or metal alloy, preferably galvanized steel or any other metal capable of providing the requisite support.

[053] It should be understood that additional stiffeners, nuts, and bolts can be added to increase strength, and that the spacing and alignment of the individual components such as, for example, the length of the cut split pipe can be adjusted to accommodate any particular structural and/or electronic fixture(s) that may obstruct attachment of an apparatus to a leg section needing to be strengthened. As an example, if a section of tower leg to be strengthened spans a distance of 20 feet between two adjacent flange joints, and there are no obstructing structural and/or electronic fixtures intervening therebetween, then a single split pipe assembly may comprise two approximately equal half pipe sections joined by one or more transition stiffeners. On the other hand, if there is/are impeding structural or electronic fixtures(s) along the 20-foot section of tower leg to which an apparatus of the invention is to be attached, it may be desirable or necessary to cut the half pipe sections in other than half sections in order to accommodate or bypass the impeding structure(s) or fixtures.

[054] In practicing the invention, generally a structural engineer would determine the appropriate size and structural capacity required of the individual components and welds to achieve the structural objectives, and detail how to fabricate the parts and install them. The apparatus would generally be fabricated in a metal fabrication shop. Measurements may be verified in the field, for example, by climbing a tower structure and obtaining accurate size and distance measurements for existing structural components including distances between flanges, flange bolt spacing, flange bolt sizes, and existing pipe leg sizes. The component parts of an apparatus of the invention would then be fabricated in a shop with final assembly and attachment to a tower leg in the field.

[055] In another aspect, the present invention relates to a process or method for reinforcing or strengthening a tower leg or section thereof. A method of the invention includes steps of fabricating and/or assembling the components parts of a single split pipe assembly apparatus of the invention in a fabrication shop, and steps to secure the apparatus to a tower leg in the field. Unlike prior methods, a method of the invention does not require any welding steps in the field.

[056] A method of the invention comprises initial steps that are carried out in a fabrication shop: 1) cutting a traditional split pipe into two or more sections, 2) welding one or more transition stiffeners onto ends of each split pipe section that are to be coupled to form a single split pipe assembly, 3) welding a plurality of flange stiffeners onto the end of the split pipe sections opposite the one or more transition stiffeners; and 4) galvanizing pipe sections after welding (if needed). After transporting the split pipe apparatus fabricated in the shop to the field, the method further comprising: 5 ) positioning the split pipe assembly adjacent to the section of existing tower leg needing to be strengthened such that the flange stiffeners at the top and bottom of each split pipe assembly rest against the existing flange joints, 6) if threaded rod stiffeners are used, the bolts are tightened to urge the two parts of the split pipe assembly into the top and bottom existing flanges, 7) if plate stiffeners are used, the plates are overlapped, drilled, and bolted together, and 8) securing the apparatus to the tower leg with a plurality of mechanical fasteners such as U-bolt connectors, and optionally applying an adhesive on all split pipe assemblies between the split pipe and tower leg surfaces, over a region of about 12 to 18 inches from the flange end toward the center of the leg.

[057] In another aspect, a process or method of the invention relates to strengthening a tower leg or section thereof by securing thereto a multiple split pipe assembly apparatus of the present invention comprising the steps of: 1) cutting a traditional split pipe into two or more sections, 2) welding one or more transition stiffeners onto ends of each split pipe section that are to be coupled into a multiple split pipe assembly, 3) welding a plurality of flange stiffeners onto the end of the split pipe sections opposite the one or more transition stiffeners; and 4) galvanizing pipe sections after welding (if needed); after transporting the split pipe apparatus to the field: 5 ) positioning the split pipe assembly to the existing tower leg needing to be strengthened such that the flange stiffeners at the top and bottom of each split pipe assembly rest against the existing flange joints, 6) if threaded rod stiffeners are used, tightening the bolts to urge the two parts of the split pipe assembly into the top and bottom existing flanges, 7) if plate stiffeners are used, the plates are overlapped, drilled, and bolted together, 8) securing the apparatus to the tower leg with a plurality of mechanical fasteners such as U-bolt connectors, and optionally applying an adhesive on all split pipe assemblies between the split pipe and tower leg surfaces, over a region of about 12 to 18 inches from the flange toward the center of the leg, and 9) applying one or more flange bypass stiffeners to assemble the multiple split pipe assembly.

[058] A method of the invention allows for easy adjustments to be made in the field to the length of the apparatus to achieve the desired result. When split pipe assemblies are needed above and/or below a flange joint, a flange bypass stiff ener is used. If an adhesive is used, an epoxy can be applied with a brush on all split pipe assemblies between the split pipe and tower leg surfaces, from the flange toward the center of the leg 12- 18 inches or as directed by an engineer.

[059] In another embodiment, the invention relates to a tower leg or section thereof having an apparatus of the invention that has been secured thereto by a process or method disclosed herein.

EXAMPLE 1

Apparatus of Invention

[060] A 100-foot self-supporting lattice tower having 3 support legs includes a 20-foot section on one leg between two flange joints that is to be strengthened. The leg section has an outer diameter of 4 inches and is free of any intervening or obstructing structural or electronic fixtures. A single split pipe assembly apparatus of the invention is prepared for the purpose of strengthening the section. The split pipe assembly includes two galvanized steel half pipe sections, each having an inner diameter of 4 inches and length of approximately 9 ¾ feet. The half pipe sections are joined by a single threaded rod transition stiffener welded to an end of each pipe section and three flange stiffeners are welded to the other end of each pipe section. The assembled apparatus leaves a gap of about 4 inches between the coupled ends of split pipe. The apparatus is transported to the site of the tower, hoisted into position, and secured to the leg section with a plurality of U-bolt connectors and epoxy adhesive. EXAMPLE 2

Tower Leg Strengthened by an Apparatus of the Invention

[061] A 200-foot self-supporting steel lattice tower includes flange joints at 20-foot intervals. A section of one leg that is to be strengthened spans three successive flange joints (i.e. 40 feet) with no obstructions on the leg section other than the flange joints. The leg has an outer diameter of 5 inches. An apparatus of the invention is fabricated in a metal fabrication shop. Steel split pipe having an inner diameter of 5 inches is cut into 4 segments each approximately 9 ¾ feet in length to prepare two single split pipe assemblies. Three flange stiffeners are welded to one end of each of the 4 segments. For each single split pipe assembly, 2 of the 4 segments are coupled together by welding two threaded rod stiffeners to the ends opposite the flange stiffeners. The apparatus components are galvanized after the welding steps. The apparatus is transported to the field and one of the single split pipe assemblies is positioned between the top two flange joints, and the other single split pipe assembly is positioned between the bottom two flange joints. The flange stiffeners are lined up to avoid contact with the flange bolts and epoxy DP420 is applied to the inner surface of each of the 4 segments covering a 12-18 inch section at the ends adjacent to the flanges and to corresponding regions of the tower leg. The threaded rod transition stiffeners are then nutted down to apply pressure on the flange stiffeners against the flanges. The two half split pipe assemblies are then clamped in place on both sides of the middle flange using a plurality of appropriately-sized U-bolt connectors. Finally, the two half split pipe assemblies are secured together by a flange bypass stiffener to complete the assembly.

[062] The foregoing discussion along with the Figures discloses and describes various exemplary implementations. These implementations are not meant to limit the scope of coverage, but, instead, to assist in understanding the context of the language used in this specification and in the claims. Upon study of this disclosure and the exemplary

implementations herein, one of ordinary skill in the art may readily recognize that various changes, modifications and variations can be made thereto without departing from the spirit and scope of the inventions as defined in the claims.