WO2025189267A1 - Mixed triangular tower - Google Patents

Abstract

The present invention relates to towers for supporting loads, such as towers for telecommunications, lighting, power transmission, wind energy, and other applications. More particularly, the invention is directed to a modular mixed triangular tower for supporting loads, characterized in that it comprises at least one first module at the base of the tower formed by: a) three tubular metal columns arranged in a triangular configuration around the vertical axis of the hybrid triangular tower; and b) a plurality of bracing members interconnecting the ends of the metal columns, wherein said members include horizontal gusseted tubular crossbeams rigidly interconnecting the upper ends of the columns of the module, and diagonal gusseted tie rods rigidly interconnecting and securing the upper ends to the lower ends of the metal columns; c) the metal columns having a diameter-to-thickness ratio (D/t) of between 20 and 150 and being filled with a composite material.

Description

MIXED TRIANGULAR TOWER

TECHNICAL FIELD

[001] The present invention belongs to the technical field of load-bearing towers, such as towers for telecommunications, lighting, power transmission, wind power and other applications.

STATE OF THE TECHNIQUE

[002] The state of the art presents various configurations of towers or posts that seek to use profiles suitable for aerodynamic performance, structural resistance with the optimized level of tension and adequate thickness of the sheet, or even that allow greater production savings, reduction of transportation and storage costs.

[003] An alternative proposed in the prior art consists of filling the tower columns with a composite material, for example concrete. The filling of tubular elements with concrete, commonly called “Concrete-Filled Steel Tubular (CFST)”, is well known in the prior art and described in depth, for example, in the book “Theory of Concrete-Filled Steel Tubular Structures” (HAN, Lin-Hai; Springer Singapore, 2023, https://doi.org/10.1007/978-981-99-2170-6), including some examples of applications in load-bearing towers.

[004] The possibility of filling the columns of a tower with some composite material, such as concrete, is also presented by this applicant; for example, in patents US9,926,717B2, BR1120130074060B1 (W02012042309A1) and BR1120170256665B1 (W02018049490A1).

[005] Other prior art patent documents also describe solutions involving tower columns filled with composite materials, such as W02004/016882A1 (US6938392(B2)), KR478325Y1 (Application No. KR20154354U) and W02006/090048 (US8201332(B2)).

Technical problem

[006] The existing solutions in the art, however, do not solve the technical problem of obtaining a tower that reaches higher heights, for example above 40 meters, or more particularly above 80 meters, maintaining an excellent balance between the use of a metal structure and the filling of the columns with a composite material. This ultimately leads to material waste and high costs. More specifically, the higher the tower, the greater the number of elements in each module from base to top, making the tower's fabrication, transportation, assembly, and maintenance expensive and complex. TECHNICAL SOLUTION

[007] To overcome the disadvantages and problems described above and other disadvantages not mentioned herein, in accordance with the purposes of the invention as described hereinafter, a basic aspect of the present invention is directed to a modular mixed triangular tower for supporting loads characterized by comprising at least a first module at the base of the tower being formed by: a) three tubular metal columns arranged in a triangular configuration around the vertical axis of the hybrid triangular tower; b) a plurality of bracing members interconnecting the ends of the metal columns, in which said members include bi-clamped horizontal tubular crossbars rigidly interconnecting the upper ends of the columns of the module and bi-clamped diagonal ties interconnecting and rigidly fixing the upper ends to the lower ends of the metal columns; c) in which the metal columns have a diameter to thickness ratio (D/t) between 20 and 150 and are filled with a composite material.

ADVANTAGEOUS EFFECTS

[008] The present invention has several advantages over the prior art.

[009] The main advantage arises from the combination of the adoption of a modular system, in which at least a first module at the base of the tower is composed of three tubular metal columns arranged in a triangular configuration around the vertical axis of the hybrid triangular tower in which the metal columns have a diameter to thickness ratio (D/t) between 20 and 150 and are filled with a composite material, with bracing members interconnecting the ends of the steel columns, in which said members include double-clamped horizontal tubular crossbars rigidly interconnecting the upper ends of the module columns and double-clamped diagonal ties interconnecting and rigidly securing the upper ends to the lower ends of the steel columns. This is because by combining steel columns with a specific diameter-to-thickness (D/t) ratio, internally filled with confined composite material, into a module, whose ends are rigidly interconnected by double-clamped horizontal tubular crossbars and double-clamped diagonal ties, there is a special aerodynamic optimization of the tower module with a very low wind-exposed area. This low wind-exposed area, in turn, is associated with a surprising gain in yield stress by 40% and a corresponding proportional increase in deformation, increasing capacity through latent resistance equal to or greater than 100%. Furthermore, the structure becomes more economical because, with confinement, the concrete provides an increase of more than 50% in the load supported by the steel tube, while concrete costs 8% of the price of steel. It is important to note that, unlike conventional prior-art solutions, the horizontal tubular crossbars and diagonal ties are double-clamped at the ends of the columns, rigidly interconnecting them so that the module behaves as an integrated structural element. The rigid double-clamped connection is essential because it allows for a 50% reduction in buckling length and a 300% increase in load capacity, given the structural behavior following the elastic stability formulas of the bars. Prior-art solutions neither anticipate nor suggest a base module with these specific characteristics.

BRIEF DESCRIPTION OF THE FIGURES

[010] Fig. 1 shows an example of application of a tower according to the present invention, including a hybrid triangular tower at the bottom and a triangular tower latticework at the top.

[011] Fig. 2 shows an example of a base module of the hybrid triangular tower according to the present invention.

[012] Fig. 3 shows an example of two upper modules of the hybrid triangular tower according to the present invention.

[013] Fig. 4 shows an example of a base module of the triangular lattice tower that adopts conventional technology.

[014] Fig. 5 shows an example of an upper module of the triangular lattice tower that adopts conventional technology.

[015] Fig. 6 shows an example of two lower modules of the hybrid triangular connected to each other according to the present invention.

[016] Fig. 7 shows the detail of an example of a column top flange.

[017] Fig. 8 shows the detail of an example of a bi-clamped connection according to the present invention.

[018] Fig. 9 shows a comparison between the lower module (hybrid triangular tower) and the upper module (lattice triangular tower) of the mixed triangular tower. DETAILED DESCRIPTION

[019] Fig. 1 shows an example of application of a mixed triangular tower (101) according to the present invention, in which in this example of application the lower part of the mixed tower adopts modules (102, 103) with composite material confined in the columns, forming a hybrid triangular tower; and the upper part adopts lattice modules (104, 105) according to the state of the art technology, forming an exceptionally advantageous set.

[020] Fig. 2 presents an example of a tower base module (102) including three tubular metal columns (106A, 106B, 106C) arranged in a triangular configuration around the vertical axis of the hybrid triangular tower; a plurality of bracing members interconnecting the ends of the metal columns (106A, 106B, 106C), wherein said members include bi-clamped horizontal tubular crossbars (107), interconnecting and rigidly fixing the upper ends of the module columns; and diagonally bi-clamped tie rods (108A, 108B) interconnecting and rigidly fixing the upper ends to the lower ends of the metal columns (106A, 106B, 106C); in which the metal columns (106A, 106B, 106C) have a diameter to thickness ratio (D/t) between 20 and 150 and are filled with a composite material.

[021] The metal columns (106A, 106B, 106C) can preferably be made of hot-dip galvanized steel or even stainless steel with geometries, or other metallic materials. The tubular metal columns (106A, 106B, 106C) can have a frusto-conical, cylindrical or polygonal geometry with a sufficient number of sides, preferably at least six, to behave as if they were substantially circular taking into account the adopted diameter-thickness ratio. Preferably, the metal columns (106A, 106B, 106C) must be of weathering steel with a strength of 350 MPa, and with protection against corrosion. The cross-section of the shell must have the sinusoidal circular effect, in order to increase the yield stress by 40%, and the corresponding proportional in the deformation; it can be polygonal as long as the number of sides has the RMS of the circle. However, other materials can be adopted for the columns such as aluminum, galvanized steel, stainless steel or a combination thereof.

[022] The composite material used for the interior filling of the columns may be, for example, concrete with a minimum compressive strength of 20 MPa or more, preferably above 30 MPa. Other composite materials may be used depending on the application, for example, grout. It is also possible to use prestressed concrete, as well as other similar systems.

[023] The bi-clamped horizontal tubular crossbars (107) that rigidly interconnect the upper ends of the metal columns (106A, 106B, 106C) of the module (102) may also have different geometries, as long as they ensure a rigid connection between the ends. upper ends of the metal columns (106A, 106B, 106C) of module (102). The rigid double-clamped connection is essential because it allows for a 50% reduction in buckling length and a 300% increase in load capacity, given the structural behavior following the elastic stability formulas of the bars. The diagonal ties (108A, 108B) connecting the upper ends to the lower ends of the metal columns (106A, 106B, 106C) can be made of steel strands, preferably double galvanized, and/or, for example, high-strength, extra-high-strength, or ultra-high-strength steel strands. Other materials, such as textile fibers or composite materials, such as Kevlar, carbon fiber, or other suitable corrosion-resistant material that also ensures protection, can also be used.

[024] The metal columns (106A, 106B, 106C) of the base module (102) must have a diameter to thickness ratio (D/t) between 20 and 150, according to each application.

[025] Fig. 6 shows an example of two lower modules of the hybrid triangular tower connected together according to the present invention. Fig. 7 shows the detail of an example of a column top flange. Fig. 8 shows the detail of an example of a connection between the column top flange and the column base flange, including the connection of the bi-clamped tubular crossbars and bi-clamped tie rods according to the present invention. The connection of the bi-clamped tubular crossbars and bi-clamped tie rods to the flange according to this example provides a rigid fixation between the upper ends of the metal columns (106A, 106B, 106C) of the module (102), and of the modules connected together according to Fig. 6, which is essential to provide a 50% reduction in the buckling length and a 300% increase in the load capacity, given the structural behavior following the elastic stability formulas of the bars.

[026] In one embodiment of the present invention, the mixed triangular tower (101) has at least one-third of the height of the tower from the base formed by modules such as the base module (102), sequentially interconnected. In the example in Fig. 1, the hybrid triangular tower that is at the bottom of the mixed triangular tower has 10 modules that follow this pattern, including the last two modules (103) shown in Fig. 3.

[027] The execution mode of the mixed triangular tower (101) represented in Fig. 1 includes a remaining upper part called a lattice triangular tower with hollow tubular metal columns with a diameter to thickness ratio (D/t) between 20 and 150. The two initial modules (104) represented in Fig. 4 follow a pyramidal configuration followed by a series of interconnected modules up to the final top section in which the modules (105) follow a prismatic configuration.

[028] The tower Fig.1 designed according to the present invention is extremely advantageous, as there is an optimization of the materials along the height of the tower. According to Table I below, it can be seen that even though the base module (102) has a distance between columns approximately 7 times greater than that of the top modules (105), the index of area exposed to the wind is one third smaller.

Table I

[029] Fig. 9 and Table II below show a comparison of the lower and upper parts of the tower. For the purpose of simplifying understanding, the upper part of the tower was designed as if it were a conventional 54-meter lattice tower, more specifically in this example the technology described in patent BR PI960177-4. In the hybrid lower part, modules with confined composite material, horizontal crossbars and tie rods are adopted. according to the present invention.

Table H

[030] According to the above data, it is found that the lower part of the tower is exceptionally advantageous, supporting a load 1033% greater than the upper part, thus allowing the conventional tower itself to be supported at the top to reach a height of 100 meters at a much lower cost than if the tower were entirely designed with the same method and shape as the conventional tower. In addition, the hybrid triangular tower designed according to the present invention has a higher natural frequency, fewer parts, a smaller index of area exposed to the wind, and lower manufacturing, transportation, assembly, and maintenance costs.

[031] For several reasons, the upper, taller part of the composite tower must be light, especially to facilitate assembly and increase the natural frequency, thus eliminating the need for bi-clamped connections and concrete confinement. The lower part of the composite tower, in the case of towers with greater loads, consists of larger shells that allow for concreting with substantial advantages, and the double-clamping between the connections improves the entire structural behavior of the tower.

Claims

01. A modular triangular mixed load-bearing tower, characterized by comprising at least a first module at the base of the tower formed by a) three tubular metal columns arranged in a triangular configuration around the vertical axis of the hybrid triangular tower; b) a plurality of bracing members interconnecting the ends of the metal columns, in which said members include bi-clamped horizontal tubular crossbars interconnecting and rigidly fixing the upper ends of the module columns and bi-clamped diagonal ties interconnecting and rigidly fixing the upper ends to the lower ends of the metal columns; c) in which the metal columns have a diameter-to-thickness ratio (D/t) between 20 and 150 and are filled with a composite material. 02. The mixed triangular tower, characterized in that at least one-third of the height of the tower from the base is formed by modules according to claim 1. 03. The mixed triangular tower according to claim 2, characterized in that the remaining upper part of the hollow tubular metal columns has a diameter to thickness ratio (D/t) between 20 and 150. 04. The mixed triangular tower according to claim 01, characterized in that the tubular metal columns are cylindrical, frusto-conical, or even polygonal with at least six sides, or a combination thereof. 05. The mixed triangular tower according to claim 01, characterized in that the metal columns are formed by aluminum, steel, weathering steel, galvanized steel, stainless steel or a combination thereof. 06. The mixed triangular tower according to claim 01, characterized in that the composite material filling the columns is concrete, grout, prestressed concrete, or a combination thereof. 07. The mixed triangular tower according to claim 01, characterized in that the upper modules are made of steel, stainless steel, aluminum or a composite material, or a combination thereof. 08. The mixed triangular tower (01) according to claim 01, characterized in that the bracing members are metallic, or composite material, or high-strength textile fibers, or a combination thereof. 09. The mixed triangular tower (01) according to claim 01, characterized in that the tie rods are steel strands made of high-strength, extra-high-strength, or ultra-high-strength steel.