FIELD OF THE INVENTION

The present invention relates generally to telecom towers and more particularly, to a ‘hexagonal -lattice’ structured telecom tower with higher resistance to wind loads, earthquake forces, and natural frequency vibrations.

BACKGROUND OF THE INVENTION

Telecom towers are vertical structures, designed and engineered for supporting telecom equipment such as antennae, remote radio units and other related telecom equipment at various heights and orientations, as per requirements, to work in conjunction with base trans-receiver stations and power supply, as a complete ‘telecom cell site’. Telecom towers structurally constructed in various forms, such as lattice-angular / lattice-tubular / round-monopole / polygonal- monopole and the likes of are used as per the need of particular application cases. The structural specifications and features of the telecom towers so used depend on the technical loading, operational requirements and site conditions.

Generally, lattice-structured towers have been more widely used, owing to their ease of manufacturing, handling, transportation, and manual installations. Historically, lattice towers with segments of square girths and structural members of steel angular sections have been used in the industry. The square girth, angular-sectioned lattice towers are although conventional, now of an antiquated design that utilizes steel-angular sectioned materials for its structural members. The square-girth, angular section tower designs have been in the wide- use as they utilize easily available raw materials, economical manufacturing processes and low-cost resources.

However, these towers pose significant disadvantages such as increased wind load. Angular structural sections make the structure less aerodynamic, and they significantly increase the wind load acting on the tower which leads to: • Use of heavier sections and additional structural reinforcements, resulting in a significant increase in the overall steel weight of the structure.

• Use of heavier RCC foundations and higher soil -bearing capacity sites.

• Cumbersome handling and lengthy installations.

• Higher overall cost of the tower, as also that of the installations, thereby raising the total cost of ownership.

It is to be noted that although as of today more efficient tower designs are available, the above square-segmented angular-sectioned towers are prescribed by many institutions. This is due to an ecosystem that lacks ongoing collaborative evaluation and adoption of newer tower designs to improve their techno-commercial impact on the industry.

However, in recent times, towers with segments of triangular girth and structural members with tubular sections are being preferred, in view of their improved economics. The triangular-tubular lattice towers have a techno-commercially more advanced design, being preferred over the aforementioned square-angular lattice towers. The triangular-tubular towers have resolved some of the latter’s problems such as the need to sustain higher wind loads with comparatively lower steel weight. However, the following areas of improvement are still observed:

• No further scope for reducing steel weight: In general, the triangular-tubular tower, although lower in weight than an equivalent square -angular tower, does not offer any scope for further optimization due to the limitations of its geometrical form and characteristics.

• Need for lighter individual members for ease of handling during installations: Geometrically, a triangular segment structure has a higher ‘un-supported length’ as compared to a square segment structure of equivalent girth. This results in longer and thereby heavier individual bracing members. Furthermore, when the wind is incidental on one face of the tower, the critical compressive loading of the entire structure has to be withstood by only one pillar member on the opposite side, requiring heavier pillar members. As a result, installations of these towers are cumbersome and time -taking.

• Need for lighter civil foundations and lower SBC at the site: Being a triangular structure, the wind forces incidental to the tower body are transferred to the ground either through two foundation contact points in the lowest wind load case, (where the wind is normal to any one vertex of the triangular tower) or through only one foundation contact point in the highest (worst) wind load case, (where the wind is normal to any one face of the triangular tower). In the highest (worst) wind load case, the maximum compressive loads are concentrated on only one pillar member, on the opposite side of the tower face. As this type of wind load can be incident on any of the tower faces, it is necessary that each of the foundation contact points is capable of offering the maximum ground reaction value, required for tower stability. Consequently, a very heavy RCC civil foundation and thereby a higher soil-bearing capacity are required at installation sites.

In conclusion, the existing towers of the prior art have drawbacks such as:

• Higher structural steel weight and therefore a higher tower cost.

• Heavier RCC foundation and thereby higher soil-bearing capacity requirements which results in high costs and long commissioning timelines.

• Cumbersome handling and installation procedures that pose safety issues, require more human resources and, which lead to longer commissioning timelines.

Accordingly, there exists a need to provide an advanced lattice-structured telecom tower that overcomes the above-mentioned drawbacks of the prior art. OBJECTS OF THE INVENTION

An object of the present invention is to provide a new-generation, design- optimized telecom tower structure with unique hexagonal girth (s) for any given case of the tower height, wind speed, seismic conditions, antennae, and equipment payload weights, as also the effective projected area thereof.

Another object of the present invention is to provide a lattice tower structure that requires the least possible steel material content, the lightest possible civil foundation, the lowest possible soil-bearing capacity at the site, and the lowest feasible land space area.

Yet, another object of the present invention is to provide a lattice tower structure that is assembled and installed manually with significant efficiency, ergonomics, and safety.

Yet, another object of the present invention is to provide a lattice tower structure with higher stability and efficiency in sustaining the wind loads as compared to prior art square -angular and triangular-tubular lattice towers.

Yet another object of the present invention is to provide a lattice tower structure with better structural survivability in events of accidents and sabotage as compared to prior art square-angular and triangular-tubular lattice towers.

Yet, another object of the present invention is to provide a lattice tower structure that offers higher resistance to lateral and twisting deflections due to wind loads as compared to prior art square -angular and triangular-tubular lattice towers.

Yet another object of the present invention is to provide a lattice tower structure with a higher natural frequency (first node frequency) of vibration thereby improving the structural performance against the ‘Resonance Design Criteria’ as compared to prior art square-angular and triangular-tubular lattice towers.

Still another object of the present invention is to provide a lattice tower structure with a higher resistance to earthquake loads as compared to prior art square- angular and triangular-tubular lattice towers. SUMMARY OF THE INVENTION

The present disclosure provides a lattice -structured telecom tower configured by a plurality of hexagonal lattice segments connected together to form a single, vertically elongated tower structure anchored to a base structure. The tower further comprises a climbing ladder secured on each of the plurality of lattice segments for enabling a user to ascend the tower structure; a plurality of platforms securely placed on intermittent lattice segments along the height of the tower structure for facilitating secure access, and a stable working area for the users; a fall arrester system configured on each of the lattice segments for ensuring safety to the user while climbing; an antenna mounting structure configured on top most lattice segment for holding antenna payloads; a lightning arrester rod secured on top of the topmost lattice segment and is connected to a conductor cable that is terminated to an earthing pit in the near vicinity of the base structure; and an aviation warning lamp mounting unit on top of the topmost lattice segment.

The plurality of lattice segments is rigidly connected to another lattice segment atop by interfacing means. Each of the plurality of lattice segments has a plurality of pillars arranged at equal space within the lattice structure and a plurality of bracing members, each rigidly connected to the adjacent pillars to form a lattice pattern that provides stability and strength to the tower structure. The plurality of lattice segments is hexagonal modular lattice segments formed by at least six pillars arranged in a hexagonal geometry with a plurality of bracing members connecting the adjacent pillars.

The plurality of the lattice segments in an assembled state ensures a balanced distribution of wind loads, providing added inherent strength and stability to the tower structure that leads to improved survivability against wind loads, better resistance to earthquake and natural frequency vibrations, as also against sabotage and the reduction in the tower deflection values thereby ensuring stable line of sight communications through stable antennae payloads.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein

Figure la illustrates an isometric view of a lattice structured telecom tower in a completely assembled state, in accordance with an embodiment of the present invention;

Figure lb illustrates a top view of the lattice structured telecom tower in the completely assembled state, in accordance with an embodiment of the present invention;

Figure 2 illustrates a pictorial representation of an individual lattice segment in the lattice structured telecom tower that has a constant hexagonal girth, in accordance with an embodiment of the present invention;

Figure 3 a illustrates a pictorial representation of the lattice structured telecom tower having a combination of lattice segments with hexagonal girths in a varying dimension with a topmost segment in triangular cross section, in accordance with an embodiment of the present invention;

Figure 3b shows a pictorial representation of the lattice structured telecom tower having a combination of lattice segments with hexagonal girths in a constant dimension, in accordance with an embodiment of the present invention;

Figure 4 a pictorial view of antennae payload mounting on the lattice structured telecom tower, in accordance with an embodiment of the present invention; and

Figure 5 a pictorial view of the antennae payload mounting arrangements on the hexagonal lattice structured telecom tower, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a lattice-structured telecom tower configured with hexagonal geometry. The tower ensures a balanced distribution of wind loads, and optimization of steel material content provides added inherent strength and stability to the structure that leads to improved survivability against sabotage, better resistance to earthquake and natural frequency vibrations, as also the reduction in the tower deflection values thereby ensuring stable line-of-sight communications.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate the corresponding parts in the various figures. These reference numbers are shown in parentheses (brackets) in the following description and in the table given below.

Referring to figures from 1 to 6, a lattice-structured telecom tower (100) (hereinafter referred to as “the tower (100)”) in accordance with the present invention is shown. The tower (100) broadly comprises of a plurality of lattice segments (1), a climbing ladder (4), a plurality of platforms (5,6), a fall arrester system (not numbered), an antenna mounting structure (7), a lightning arrester rod (8) and a mount for the aviation warning lamp (9). The plurality of lattice segments (1) are connected together to form a single, vertically elongated tower structure anchored to a base structure (300). The tower (100) is a ground-based tower consisting of lattice segments (1) connected one on top of the other, and anchored to a conventional RCC civil foundation that acts as the tower base (300) for stability.

In one of the exemplary embodiments, the tower (100) is engineered as a portable footings-based tower (PFBT). The tower consisting of multiple modular rigid segments (1) with a hexagonal girth structure.

In the embodiment, each of the plurality of lattice segments (1) are modular rigid segments connected one on top of the other, and anchored to a base structure (300). Each of the plurality of lattice segments is rigidly connected to another lattice segment (1) atop by interfacing means. In a preferred embodiment, the base structure (300) is a pre-cast, portable footing.

In the embodiment, each of the plurality of lattice segments (1) is modular rigid hexagonal lattice segments (1) that are rigidly connected together with another lattice segment (1) atop by interfacing means. Each of the plurality of lattice segments (1) contains a plurality of pillar members (2) (“pillar (2)” hereinafter) arranged at equal space within the lattice structure and are arranged in a hexagonal geometry. The pillars (2) are further rigidly connected to a plurality of bracing members (3), to form a lattice pattern that provides stability and strength to the tower structure. Thus a plurality of pillars (2) and the bracing members (3) together forms a hexagonal modular lattice segment (1).

Referring to figures la&lb, a pictorial view of a lattice structured telecom tower in a completely assembled state is shown. The tower (100) includes a plurality of modular segments (la) with a constant hexagonal girth throughout the height thereof and connected to each other with suitable interfaces.

In one of the exemplary embodiments, the plurality of segments (1) are connected to each other by means of overlapping rib joints provided at the ends of each of the pillars (2). Each pillar (2) includes a plurality of rectangular ribs (not numbered) provided at the ends thereof. This plurality of rectangular ribs is perpendicular to the girth of the pillars (2). The length of the rectangular ribs extends outward along an axis of the pillars (2) such that the overhanging portion of each rectangular rib, partially or fully overlaps with that of the corresponding ribs of the consecutive pillars (2) at the time of assembly/installation. These consecutive pillars (2) are rigidly connected to each other at the above overlapping rectangular ribs by means of anyone of welded, bolted and other suitable joints.

In one of the exemplary embodiments, the tower (100) comprises a plurality of lattice segments (1) each having a plurality of pillars (2) connected to the immediate next pillar (1) of the top segment (1) by means of flanged connections.

Referring to figure 2, a pictorial view of an individual lattice segment (1) having a constant hexagonal girth is shown in accordance with an embodiment of the present invention. The lattice segment (1) is formed by at least six pillars (2) with a plurality of bracing members (3) connecting the adjacent pillars (2) arranged in a hexagonal configuration. In the embodiment, each of the plurality of segments further comprises a plurality of cable tray brackets mounted on the plurality of pillars (2).

In an embodiment, the pillars (2) and the bracing members (3) of each segment (1) are fabricated out of round, tubular steel sections also known as circular hollow sections or CHS.

In one of the exemplary embodiments, both the pillars (2) and the bracing members (3) are constructed out of any other sections such as square-tubular (also known as square hollow sections or SHS), angular, round-bar or in a combination thereof from any other materials deemed fit for the design considerations of the tower (100).

In one of the exemplary embodiments, the plurality of pillars (2) and the bracing members (3) are connected to each other by welded joints, riveted joints, chemically-bonded joints such as by using industrial adhesives, inter-lock joints such as by using innovative interface geometries of the mating structural members, pin joints such as by using specially designed pins, having an interference fit, and quick-clamping joints such as by using latched clamps.

In one of the exemplary embodiments, the plurality of pillars (2) and the bracing members (3) are connected to each other at gusset plate joints / overlapping rib joints by fastening means such as bolts and nuts.

Referring to figure 3a, a pictorial view of the lattice -structured telecom tower, in accordance with an embodiment of the present invention is shown. In the embodiment, the tower (100) includes a combination of lattice segments (1) having hexagonal girths, progressively reducing from bottom to top and having a topmost segment with triangular, square and any other cross-sectional geometry, deemed fit as per the design considerations of the structure.

In one of the exemplary embodiments, the tower (100) includes a combination of lattice segments (1) having hexagonal girths, progressively reducing from bottom to top.

In one of the exemplary embodiments, the lattice segments (1) are arranged with progressively reducing hexagonal girths from bottom to top in either a gradually tapered form or a stepped form.

Referring to figure 3b, a pictorial view of the hexagonal lattice -structured telecom tower, in accordance with an embodiment of the present invention is shown. In the embodiment, the tower structure is made by a combination of lattice segments (1) with hexagonal girths, in a constant dimension. In one of the exemplary embodiments, the tower structure is made by a combination of lattice segments (1) with hexagonal girths, in a constant dimension with a topmost segment in a variety of cross-sectional geometry configured. The topmost segment is having a geometry selected from triangular, square and any other cross-sectional shape at the top / higher levels deemed fit as per the design considerations of the structure.

Further, the topmost lattice segments (1) consist of suitable mounting arrangements at the top for mounting the antennae payloads (200). In one of the exemplary embodiments, the antennae payloads (200) are mounted on an antennae mounting structure (7), as well as directly on the pillar (2) of the topmost segment (1). The antennae mounting arrangements are configured on the segments (1) over a range of heights from the bottom to the top of the tower (100) as shown in figures 4 and 5 as per application requirements.

Referring to figure 4, a pictorial representation of an antennae payload mounting arrangement on the hexagonal lattice structured telecom tower is shown in accordance with an embodiment of the present invention. In the embodiment, the antennae payloads (200) are mounted directly on to the plurality of pillars (2) of the topmost segment (1).

Referring to figure 5, a pictorial view of an antennae payload mounting arrangement on the hexagonal lattice structured telecom tower, in accordance with an embodiment of the present invention is shown. In the embodiment, the antennae are mounted on a separate ‘antenna mounting structure (7) provided at the top of the tower (100). The antenna mounting structure (7) includes a plurality of support rings (7a) bolted to the plurality of pillars (2) of the topmost segment (la). The plurality of support rings (7a) is further connected to a plurality of mount poles (7b) to allow for the connection of the antennae/payload components thereon. Each of the plurality of mount poles (7b) is capable of holding the telecom payloads (200), such as RF Antenna, Microwave Antenna, Remote Radio Unit (RRU) and direct current distribution boards (DCDB) and like.

In one of the exemplary embodiments, the climbing ladder (4) is provided on each segment (1) for enabling the riggers/technicians to ascend the tower structure for installation/maintenance of the antennae payload (200). The plurality of rest platforms (5) is provided intermittently along the height of the tower (100) for facilitating fatigue relief to the riggers/technicians, ascending/descending the tower (100). The work platform (6) is provided at the topmost segment (1) to facilitate secure access, and a stable working area for riggers/technicians, while carrying out antennae installation/maintenance activities.

In one of the exemplary embodiments, the lattice segments (1) are also provided with a fall arrester for ensuring the safety of the climbers while ascending the tower (100). The fall arrester system is made in form of a wire rope, a rope-grab, and a hydraulic/pneumatic dampener.

In one of the exemplary embodiments, the lightning arrester rod (8) is provided on the top segment, and connected to a conductor cable that is terminated to an earthing pit in the near vicinity of the tower base. This protects the tower (100) and antenna payload (200) by safely transferring the strong electric currents through the conductor cable and to the ground in the event of a lightning strike. The top segment is provided with a mounting interface for the installation of the aviation warning lamp (9) thereon in compliance with statutory requirements.

Further, a plurality of cable trays/brackets for mounting cable trays (2a) are provided to appropriately and safely route electrical cables from the tower base to the antennae payload (200) as shown in figure 2.

In one of the exemplary embodiments, the tower (100) is a 40 m tall structure capable of supporting antennae payload (200) of three telecom operators, at wind speeds of up to 200 km/hr. However, it is to be understood that the tower (100) may be designed for varying heights, antennae payloads (200), wind speed sustenance, seismic sustenance, ground footprints, base utility payloads and combinations thereof in various configurations, such as ground-based towers (with conventional RCC foundations), portable footing-based towers, and other structural configurations.

In one of the exemplary embodiments, the tower (100) is engineered as a roof- top-based tower (RTTs). The tower (100) comprises of multiple modular rigid segments (1) with hexagonal girth fitted one above the other. The lower segment is mounted on a civil foundation, constructed on a building roof-top that acts as the tower base (300). In one of the exemplary embodiments, the tower (100) is trailer-based / skidbased (also known as a cell on wheels (COWS)). The tower comprising of multiple modular rigid segments with a hexagonal girth based on a trailer-chassis or a steel skid-platform that acts as the tower base (300).

In one of the exemplary embodiments, the tower (100) is a self-supported structure.

In one of the exemplary embodiments, the tower (100) is configured as a ‘guy- supported’ structure.

The advantage of the present invention according to the embodiments are:

The hexagonal geometry of the tower (100) results in a higher and densely distributed number of ‘structural nodes’ as compared to prior art towers. This results in a uniform and effective load-sharing, which drastically reduces the structural material mass and grade requirements, consequently significant tower capex cost. This also results in the most efficient manual installations due to the comparatively smaller and lighter members. Further, the six foundation connection points, help in the distribution of the wind loads on a larger number of the main structural leg members of the tower, reducing the bearing strength requirements of the RCC civil foundations, consequently, the significant reduction in the cost of Footings vis-a-vis the conventional foundations. The major objectives met by the tower are as follows:

Uniform distribution of mass: The Hexagonal Lattice Structure offers a higher section modulus that derives strength of the tower structure while requiring lesser mass due to the unique geometry. Further, the hexagonal geometry uniformly distributes the mass of the structure and offers a more effective structural rigidity as possible for multi-plane loadings comparatively with higher stability and wind load sustenance than existing lattice towers.

Uniform distribution of load: The hexagonal geometry of the lattice segments (1) provides a higher number of nodal, load-sharing and distributing points to sustain and transfer for the eventual reaction from the ground. Furthermore, the hexagonal geometry offers the maximum number of vertical members such as pillars (2) that share the overall load on the tower (100). This reduces the load on each of the individual members in the lattice segments (1) and eventually helps to reduce the mass of each member, the tower-to-foundation connections; and further the mass of the foundation itself.

Reduced land area requirements: With the optimized distribution of the loads on the Tower structure, the loads are also distributed in an optimized manner on the foundation, thus the overall load effectively being shared by a given area of the ground; hence the soil-bearing capacity for the Tower is relatively reduced. Further, the tower (100) requires reduced bearing strength for the RCC civil foundations, and also the soil beneath, by ~ 40 % compared to the triangular towers and ~ 20 % against square towers. This reduces the cost of footings/foundations proportionally. The reduced bearing capacity requirements of the tower lead to reduced land area requirements and thereby reduced landacquisition / land-rental costs.

Cost effectiveness: The optimized distribution of loads on the tower structure, the foundations and the Ground eventually; thus the overall weights of the Steel structures and concrete are reduced, thus lowering the overall costs significantly. The hexagonal geometry of the tower (100) results in a higher and more densely distributed number of ‘structural nodes’ as compared to prior art towers thereby causing efficient load sharing, reduced material mass and grade requirements, the cost and easier manual installations due to smaller and lighter members.

Balanced distribution of wind loads: The hexagonal Lattice Structure offers a higher section modulus while requiring lesser mass due to its unique geometry, wherein the mass of the structure is uniformly distributed thus offering a more effective structural rigidity for the possible multi-plane loadings. Thus the hexagonal geometry of the tower (100) ensures a balanced distribution of wind loads, providing added inherent stability to the structure that leads to improved survivability against sabotage, better resistance to earthquake and natural frequency vibrations and a reduction in the tower deflection values thereby ensuring stable line of sight communications. The tower (100) provides the best trade-off between parameters such as force distribution within the structure, the cross-sectional shape of segments, and steel weight, viz-a-viz cost-effective manufacturability.

Higher resistance to lateral and twisting deflections due to wind loads: The hexagonal lattice in the tower (100) is configured with segments having larger girth at the base and smaller girth at the higher or top level, such that the top segment of the structure is closest to the centre axis and also possesses uniform structural elements that result in a balanced wind force around the axis. This helps to offer a higher resistance to twisting of the top segments. Further, the hexagonal geometry of the lattice structure at the lower segments is uniform in construction and the structural elements of this hexagonal configuration are all nearest to the outermost circumference of the structure, therefore eliminating the possibilities of unbalanced wind force on any uneven projections which is otherwise the primary reason leading to the twisting of a structure around its axis.

Structural survivability in events of accidents and sabotage: The tower consists of multiple modular rigid segments (1) with a hexagonal girth structure. In the embodiment, the multiple modular rigid segments (1) are connected one on top of the other and anchored to a tower base (300). In one of the exemplary embodiments, the tower (100) base is engineered as a pre-cast, portable footing portable footings-based tower (PFBT). Since these portable footings are placed and positioned above the ground level, the Hexagonal Lattice Tower base is elevated and above the ground level. As such, if there is any event of earthmoving equipment or truck accidentally approaching and impacting the base of the Tower, the tower structure shall not directly bear the impact as the vehicle shall hit the elevated footing. The chances of the Footings being affected severely shall be very less as the overall mass of the Footings that are also playing the role of the ‘Counterweight for the Tower’ shall contribute a much higher moment of inertia than the incidental force exerted by the vehicle. Higher natural frequency of vibration: By adopting the unique hexagonal geometry the tower structure is capable of achieving higher resistance to deformation, whereby the natural frequency is lowered in value as compared to prior art to prior art techniques such as the square -angular and triangular-tubular lattice towers. Hence, the tower (100) offers a higher natural frequency (first node frequency) of vibration thereby improving the structural performance against the ‘Resonance Design Criteria’ as compared to the prior art techniques.

Higher resistance to earthquake loads: Compared to the prior art towers, as the hexagonal lattice tower possesses a higher structural rigidity, the tendency of oscillating due to earthquake amplitude can be much more controlled/reduced.

Thus the tower (100) provides the best geometrical configuration to achieve advantages such as, i) better overall strength & stability of the structure, vis-a-vis the optimized tower structural weight and cost; ii) uniform force distribution within the entire structure and effective transfer of the loads finally to the footings, iii) loads being distributed over an optimized area to reduce the soil bearing capacity, iv) reducing the land space requirement, v) providing for cost-effective and productive manufacturability.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the present invention.