BRPI0902183A2 - lattice beam - Google Patents

Abstract

TRELIED BEAM The present invention relates to a truss beam configuration, comprising pre-drilling the flanges, with two or more (parallel) tandem holes (14) for each half knot, conveniently spaced apart (dl, d2), to producing diagonals (12) according to a predetermined distance between the flanges, with only one hole, or pair of spindle holes, for fixing on the flanges (11) at each end thereof; mounting the truss with two or more diagonals (12) parallel at the same angle interspersed with two or more diagonals at opposite angles at a given step (P) defined for the beam (from the original predefined step for the banzo) , resulting in a simpler assembly process because standardized parts allow the composition and installation of beams in a shorter time and with much less complexity.

Description

TRAINED BEAM

Summary of the Invention

The present invention relates to a main truss beam configuration, and additional configurations in alternative truss beam embodiments.

Background of the Invention

The present invention relates to the difficulties inherent to the lattice beams production process, depending on the prior knowledge of the requests (s) and load (s) to which the beams will be subjected.

The present invention also relates to the difficulties inherent in the installation and assembly of surveillance structures.

In the current technique, lattice beams have to be produced according to the previously determined desired span and load, making it impossible to store prefabricated material and determining higher cost and time of beam preparation.

Although normally lighter than solid structures, lattice beams end up being neglected because of the slow and expensive process of custom production, and projects of greater detail and complexity typically have a greater possibility of problems during execution.

Truss beams are therefore effectively used only in specific situations where there is no doubt about their benefits compared to solid beams.

The present invention provides a novel and inventive solution to the limitations in the state of the art, as it includes a new wireframe connection configuration and manufacturing process, which allows the easy industrialization, storage and assembly of parts that make beams, in different configurations and shapes. , without height limitations and spans and loads, making it more attractive to use, allowing substantial cost savings and lead times, ensuring finished beam compliance with design, and allowing easy replacement of parts and pieces of the beam with ease, speed and smaller. costs.

In addition, the parts that make up the beam resulting from the present invention have the same structural integrity and load carrying capacity currently verified for existing reinforcement, with the obvious advantage of being produced in series and stored prior to their use in a defined design for their application.

Description of the Figures

The present invention is illustrated by the attached figures 2 to 9, wherein: Figure 1 and IA comprise prior art representations; Figures 2, 2A, 2B, 3 and 3A comprise representations of one embodiment of the present invention; Figures 4, 4A, 4B, 5, 5A and 5B comprise representations of a second embodiment of the present invention comprising a "Z" flange; Figures β, 6A and 6B comprise representations of the "Z" banzo; Figure 7 comprises a representation of one embodiment of the present invention; Figures 8 and 8A comprise a representation of another embodiment of the present invention; and Figure 9 represents another embodiment of the present invention.

Detailed Description of the Figures

Figure 1 and IA comprise previous datatechnical representations showing a banzo (10 and diagonals (2). The current technique is evidenced in detail IA, comprising the fixation of the diagonals through two holes arranged (β) in the banzo, referred to Figure 1 and also showing the step (P) between the nodes;

Figures 2, 2A, 2B, 3 and 3A comprise representations of one embodiment of the present invention, and Figure 2 illustrates the use of two parallel diagonals, with horizontally arranged fixing holes relative to the flange, showing step (P); The

Figure 2A details the assemblies of diagonals (12) fixed at the knots to the flange (11), at fixing points or holes (14); and Figure 2B details the x-x cut, showing the fixation elements in relation to the flanges (11) and diagonals (12);

Figures 3 and 3A (detail) schematically represent the advantages of the present invention in relation to the possibility of different heights and spans using the same drilling arrangements and distance between holes in the flange.

Figures 4, 4A, 4B, 5, 5A and 5B comprise representations of a second embodiment of the present invention comprising a "Z" banzo, and Figures 4, 4A, 4B show a first embodiment of the "Z" banzo; and Figures 5, 5A and 5B a second "Z" flange mode. Figures 4A, 4B show a metal structure with upper and lower flanges (21) and diagonals (26) with fixing holes (25), said flange having upper (22) and lower flaps (23), and an intermediate body (24 ), as shown in Figure 4A, and in Figure 4B the fixing of the flange (21) and diagonals (26) by means of the fixing element (25A) is shown.

Figures 5, 5A and 5B show a second modality of the "Z" flange, in a metal frame upper and lower combos (31) and diagonals (36) with fixing holes (35), said flange having upper flaps (32) and lower (33), and a two-part partitioned body (34 and 34a) and as shown in Figure 5A, in which figure 5B shows the attachment of the flange (31) and diagonals (36) by means of a fastener (35A).

Figures 6, 6A and 6B comprise representations of the "Z" flange, and Figure 6 shows that once rotated and inverted, said banzo can be nested therein, thus enabling its storage and improved additional use, such as for extension, connection or structural reinforcement (Figures 6A and 6B);

Figure 7 comprises a representation of one embodiment of the present invention;

Figures 8 and 8A comprise a representation of another embodiment of the present invention, with diagonally set holes in the flange vertically disposed relative to said flange, Figure 8 further comprising applying an additional structural element between the diagonals; and

Figure 9 represents a further embodiment of the present invention, with nobano diagonal fixing holes arranged vertically with respect to said flange, with only two holes per knot.

DETAILED DESCRIPTION OF THE INVENTION The traditional lattice beams are basically made up of two main pieces: the flanges (1), long-length longitudinal pieces, and the diagonals (2), shortest transverse pieces, usually positioned between two flanges, with their ends each connected to one another. flange by conventional bolts and nuts, and may further comprise one or more plumbs vertically positioned between the flanges.

The constructive shape of the beams is determined by the length of the diagonals (2) and the pitch (P - internode distance or connection points between the flange and the diagonal) required to obtain span, height and load bearing capacity.

In conventional process, the detailing or determination of holes in the flanges and size of the diagonals can only be started after determining the requests, loads and spans to which the beam will be submitted, and the beam height allowed by the project.

The detail therefore consists in defining the sections of the pieces, flanges and diagonals, the step (or distance) between the nodes and the shape of the connections, which in turn define the diagonal length and the height of the beam.

As already mentioned, conventional lattice beams are manufactured on demand according to specific requirements for spans and engineered loads, and precast and stocking of the main component parts is impossible because the specifications for spans and loads determine the holes in the flanges, the length of the diagonals and, mainly, the angle (β) of the diagonals (2) in relation to the flanges (1).

In situations where it is necessary to transfer strength to the connecting elements by means of two or more fixing holes, in line and in the longitudinal direction dadiagonal (2), an angle (β) is defined for this with respect to the bushing (1) and, for a height of the beam, the step (P) for arranging said fixing holes.

The most obvious advantages of the present invention over the prior art are:

a) pre-drilling the flanges, with two or more tandem holes (14) for each half knot, conveniently spaced apart (dl, d2), enables a wide angle range for the diagonals to a desired step (P);

b) the production of diagonals (12) according to a predetermined distance between the flanges, with only one hole, or pair of spindle holes, for fixing on the flanges (11), at each of its ends;

c) mounting the truss with two or more diagonals (12) parallel at the same angle interspersed with two or more diagonals at opposite angles, at a step (P) defined for the beam (from the original preset step for the banzo) define a height, allowing to meet wide range of spans and load with the same configuration of flanges (11), varying only the length and, therefore, the angle of the diagonals, for the definition of the height;

d) the immediate availability of more complex parts, such as flanges (11), and the supply of less complex parts, the diagonals (12), in definite or almost immediate demand, allows a much shorter term supply of structural elements; and

e) The simpler assembly process and standardized parts allow the composition and installation of beams in a shorter time and with much less complexity.

Due to the configuration represented by the present invention, the larger and more worked main part, which is the banzo (11), can be prefabricated and subsequently stored for later use; and the diagonals (12), simpler and quicker and more easily produced parts, can also be prefabricated and stocked, with only one spindle hole (14) at each end, and in varying lengths.

The present invention comprises lattice beams which may be constructed in different ways, the configuration being following the preferred mode, not restrictive to the concept for which protection is sought.

In the configuration of the present invention, in order to meet the efforts to be transferred by the diagonals to the loops, two diagonals (12) are used in parallel in beam registration, each capable of meeting the desired half request, fixed to the flange by a screw at each end, allowing the height to be variable, making the trellis competent to handle different requests.

This configuration allows for standardization of production, facilitates administration and maintenance of stocks for prompt delivery, reducing to almost zero the normal lead time of such a supply.

In the embodiment of the present invention, a banzo (11) may be manufactured and stored for use at any lattice height, which height will be defined as required demand.

Flanges (11) and diagonals (12) may be calculated taking into account material thickness constraints, maximizing, with one axis, the capacity of the joints and intervening parts.

The present invention therefore provides a case comprising a longitudinal main part, or flange (21,31), with a characteristic "Z" profile, according to Figures 4 to 5B, comprising spaced-apart holes (25, 35) located at points such specific points comprising at least four holes, two holes for each pair being diagonal (26, 36), such diagonals (26, 36) being attached to the bracket (21, 31) by fasteners (25A, 35A), most commonly shaft fixing screws at their ends, the diagonal (26, 36) in double being angled according to the design specifications.

Said "Z" piece, as shown in Figures 4 to 5B, comprises a two-flap upper (22, 32) and lower (23, 33) profiled steel plate disposed at the vertical ends of the neck. further comprising an intermediate surface or body (24, 34) between the two tabs, said surface comprising four or more fixing holes (25, 35) of the diagonals (26, 36), said holes being disposed in the central, upper and / or lower part intermediate body.

In the second embodiment illustrated by FIGS. 5 to 6B, said "Z" shaped piece comprises a two-flange upper (32) and lower (33) profiled steel plate disposed at the vertical ends of the bank (31), further comprising a section upper section 34a, an intermediate section 34b and a lower section 34c between the two flaps, the upper section 34a being between the upper flap 32 and the intermediate section 34b and the lower section 34c being comprised between the lower flap (33) and the intermediate section (34b). In this configuration, the middle section (34b), comprised between the upper (34a) and lower (34c) sections, has a characteristic angle in relation to both upper and lower sections, said angle being sufficient to confer greater resistance to the joint, and conferring greater structural resistance to the part. . Further, said upper (34a) and lower (34c) surfaces comprise four or more diagonals fixing holes (35).

The truss beam resulting from the present invention comprises two parallel flanges (11, 21, 31) connected by diagonals (12, 22, 32), said diagonals being fixed to the flanges by fasteners (14, 25A, 35A) at their ends. The fixing holes (14, 25, 35) of the diagonals of the present invention are arranged side by side sufficiently spaced to allow the angulation of the diagonals.

In an alternative embodiment, each set of fixing holes of each node comprises an additional hole centrally positioned between the other holes, fixing of additional structural element vertically disposed and fixed by a fixing element to the flanges at their ends.

At this point it is noteworthy that the "Z" or banzo profile piece (31) can be a structural reinforcement element (Fig. 6B) or a splicing element (Fig. 6A) in the knot section.

As a reinforcement element, a section of said beaker (31), containing all or part of the holes (35), is superimposed over an existing flange (31) and bolted to the same, together with the diagonals (36), thus constituting an element of knot reinforcement.

In the splice mode, two flanges (31) may be interconnected to their holes (35) or knots and fixed by overlapping a section of said flange (31), containing all or part of the holes.

The possibility of using the overlapping banzo is due to the fact that said banzo (21, 31) has characteristic geometry that allows its conformation, overlapping and after rotation, to another banzo, as illustrated in Fig. 6

Furthermore, the present invention provides, in alternative mode, the arrangement of vertical-hole drilling, as illustrated by figures 8, 8A and 9, and one of these alternative embodiments is the diagonally deflected hole shared by two opposite diagonals, as illustrated by Figure 9, such a configuration being in accordance with the scope of the present invention the banzo / diagonal relationship.

Furthermore, the present invention provides a process for the fabrication of lattice beam structures comprising, in its basic configuration:

(a) the manufacture of profiled flanges with specified longitudinal spacing and spaced from one another;

b) determining the distance between the flanges and the angle required for the diagonals;

c) the manufacture of diagonals in specific size and thickness;

d) the fixing of at least two diagonals, parallel and at predetermined angulation, in one of the beam sections and between the flanges, by the use of fastening elements; and

e) the fixing, in the section of the beam adjacent to the section of the first diagonal fixation, of at least two diagonals between the flanges, parallel and in predetermined angle and opposed to the angle of the immediately preceding section, by means of truss, by means of the fixing elements. ; and

f) repeating the previous steps d) and e), as often as necessary to form the desired lattice beam.

In the present invention, depending on the load and are determined for the beam, only one diagonal can be fixed per section of the truss beam.

The present invention is characterized in that it permits the anticipated production of the main profile (flanges) for stocking and immediate delivery since the profile is perforated such that they can be connected with cross-strips (diagonals, or plumbs, etc.) of different lengths, forming trusses and resembling different heights and load capacities, their own different spans and loads, regardless of the gap and the requirements to be applied.

The present invention is further characterized by the form of connection at each node of the transverse elements which are joined to the longitudinal elements, each connected by one or a pair of screws (or the like) constituting axes in number of transverse elements compatible with the structural demands of the transverse force. desired.

The above explanation, however broad, does not exclude other embodiments that may possibly arise from the present invention, either by a constructive differentiating model or by novel features contemplated as a result of the practical development of the present invention, and therefore the present invention is not limited to the topics described above.

1. TRAINED BEAM, OF A TYPE OF UPPER AND LOWER FLOWS (11, 21, 31) AND TWO DIAGONAL ASSEMBLIES (12, 22, 32), THE BONDS (12, 22, 32) OF A SET BEING ARRANGED BY THE SAME DIRECTIONALLY DELAYED of the direction of the diagonals of the other set, said diagonals (12, 22, 32) having their upper and lower extremities respectively fixed in denó (N) regions of the flanges, said beam being characterized by the fatode of each of the upper flanges (11, 21, 31) and lower shall be provided with at least one longitudinal alignment of furostransversal (14, 25, 35) separated from each other for each set of diagonals (12, 22, 32) by at least one predetermined distance (dl, d2), each Diagonal (12, 22, 32) comprises at each of its upper and lower ends a single through hole to be aligned with the transverse hole (14, 25, 35) of the upper and lower flanges (11, 21, 31) respectively. , each set of transverse and through holes, aligned between s i by receiving and retaining a securing pin (25A, 35A).

Lattice beam according to Claim 1, characterized in that each of the diagonals (12, 22, 32) comprises at least two closely adjacent parallel diagonals disposed between adjacent diagonals of the other diagonal joint, and having their upper and lower extremities fixed in the same node (N) of the upper upper flanges (11, 21, 31), respectively.

Truss beam according to claim 2, characterized in that the transverse holes provided in each node (N) of each of the upper and lower flanges are spaced apart by a predetermined distance (dl, d2) to allow fixation of diagonals of different lengths in the upper and lower flanges, lattice trusses having different heights.

Lattice beam according to any one of Claims 1 to 3, characterized in that each upper and lower flange comprises a symmetrical profile (21, 31) in approximate "Z" shape, with two upper wings (22, 32) and (23, 33), of the same size, and an intermediate section (24, 34) arranged orthogonally to the tabs, parallel and spaced apart, each being incorporated at one end of the intermediate section end, said profile comprising furostransversal nodes (N) , the upper and lower flanges provided in the middle section.

Lattice beam according to claim 4, characterized in that the symmetrical profile (21, 31) in approximate "Z" shape further comprises a small central portion (34b) disposed in the middle section (34).

Truss beam according to claim 5, characterized in that the transverse holes (25,35) of the nodes (N) of each of the flanges are provided in at least one of the upper (34a) and lower (34c) portions. intermediate section (34) of the respective profile (21, 31).

Lattice beam according to Claim 4, characterized in that one or more regions of the Profile nodes (N) of one or both lower and lower flanges are reinforced by a profile extension (31A) having their end flaps and their intermediate section seated, respectively, on the end flaps laterally against the middle section of the profile node (N) region, at least one of the portions (34a, 34b) of the profile extension provided with the same furostransversal provided in each node (N) of each of the upper and lower flanges for receiving and retaining the respective fixing pins (50).

Truss beam according to any one of claims 4 to 7, characterized in that each profile flange incorporates at its free end a small bias towards the plane of the other flap, but inclined outwards.

Truss beam according to any one of claims 4 to 8, characterized in that each upper and lower flange comprises two "Z" shaped profiles, arranged side by side, with the tabs defining the respective extreme longitudinal edge of the beam. lattice, arranged coplanarly and facing each other, the transverse holes in each node (N) being drilled in the innermost portions of the intermediate section (24, 34) of each pair of profiles, between which the upper and lower extremities are tapered. respectively of the diagonals (26, 36).

Lattice beam according to claim 9, characterized in that each diagonal comprises a "C" shaped profile with its side flaps seated against the innermost mid-section portions of the two forming profiles of each of the upper and lower flanges.

11. TRACKED BEAM, OF A TYPE OF UPPER AND LOWER BLOG (11, 21, 31) AND TWO DIAGONAL ASSEMBLIES (12, 22, 32), THE BONDS (12, 22, 32) OF A SET BEING ARRANGED BY THE SAME DIFFERENTLY DELAYED DIRECTION of the direction of the diagonals of the other set, said diagonals (12, 22, · 32) having their upper and lower extremities respectively fixed in denó (N) regions of the flanges, said beam being characterized by the fatode of each flange (11, 21, 31) The upper and lower sections shall be provided with at least one vertical alignment of separate transverse furostroms for each set of diagonals by at least one predetermined distance, each diagonal comprising in each of its upper and lower extremities a single through hole. to be aligned with a transverse hole of the upper and lower flanges, respectively, each set of transverse and through furostrans aligned with each other, receiving an upright pin (25A, 35A).

Truss beam according to claim 11, characterized in that each of the diagonals sets comprises at least two parallel diagonals, closely adjacent to one another and disposed between adjacent diagonals of the other set of diagonals, with their upper and lower ends fixed. at the same node (N) of the upper and lower flanges, respectively.

Lattice beam according to claim 12, characterized in that the transverse holes provided in each node (N) of each of the upper and lower flanges are spaced apart by a predetermined distance (dl, d2) to allow the attachment of diagonals. different lengths in the upper and lower flanges, latticed trusses with different heights.

14. TRAINED BEAM, of a type comprising an upper and lower flange (11, 21, 31) and two diagonal assemblies (12, 22, 32), the diagonals (12, 22, 32) are arranged in an angularly offset direction relative to another, said diagonals (12, 22, 32) having their upper and lower extremities respectively fixed in regions of knots (N) of the flanges, said beam is characterized by the fact that each of the upper and lower flanges (11, 21, 31) is provided with at least one furotransverse, for each set of angularly-offset diagonals, each diagonal comprising, at each of its upper and lower ends, a single fascia to be aligned with a transverse hole of the upper and lower flanges, respectively, the overlapping and forward diagonals. fixed through the passing transverse holes, aligned with each other, receiving and holding a fixing pin (25A, 35A).

Lattice beam according to claim 14, characterized in that the transverse holes provided in each node (N) of each upper and lower flange are spaced apart by a predetermined distance (d2) to allow the fixing of diagonals of differing lengths. in the upper and lower banks, lattice trusses with different heights.

Claims (15)

1. TRAINED BEAM, OF A TYPE OF UPPER AND LOWER FLOWS (11, 21, 31) AND TWO DIAGONAL ASSEMBLIES (12, 22, 32), THE BONDS (12, 22, 32) OF A SET BEING ARRANGED BY THE SAME DIRECTIONALLY DELAYED of the direction of the diagonals of the other set, said diagonals (12, 22, 32) having their upper and lower extremities respectively fixed in denó (N) regions of the flanges, said beam being characterized by the fatode of each of the upper flanges (11, 21, 31) and lower shall be provided with at least one longitudinal alignment of furostransversal (14, 25, 35) separated from each other for each set of diagonals (12, 22, 32) by at least one predetermined distance (dl, d2), each Diagonal (12, 22, 32) comprises at each of its upper and lower ends a single through hole to be aligned with the transverse hole (14, 25, 35) of the upper and lower flanges (11, 21, 31) respectively. , each set of transverse and through holes, aligned between s i by receiving and retaining a securing pin (25A, 35A). Lattice beam according to Claim 1, characterized in that each of the diagonals (12, 22, 32) comprises at least two closely adjacent parallel diagonals disposed between adjacent diagonals of the other diagonal joint, and having their upper and lower extremities fixed in the same node (N) of the upper upper flanges (11, 21, 31), respectively. Truss beam according to claim 2, characterized in that the transverse holes provided in each node (N) of each of the upper and lower flanges are spaced apart by a predetermined distance (dl, d2) to allow fixation of diagonals of different lengths in the upper and lower flanges, lattice trusses having different heights. Lattice beam according to any one of Claims 1 to 3, characterized in that each upper and lower flange comprises a symmetrical profile (21, 31) in approximate "Z" shape, with two upper wings (22, 32) and (23, 33), of the same size, and an intermediate section (24, 34) arranged orthogonally to the tabs, parallel and spaced apart, each being incorporated at one end of the intermediate section end, said profile comprising furostransversal nodes (N) , the upper and lower flanges provided in the middle section. Lattice beam according to claim 4, characterized in that the symmetrical profile (21, 31) in approximate "Z" shape further comprises a small central portion (34b) disposed in the middle section (34). Truss beam according to claim 5, characterized in that the transverse holes (25,35) of the nodes (N) of each of the flanges are provided in at least one of the upper (34a) and lower (34c) portions. intermediate section (34) of the respective profile (21, 31). Lattice beam according to Claim 4, characterized in that one or more regions of the Profile nodes (N) of one or both lower and lower flanges are reinforced by a profile extension (31A) having their end flaps and their intermediate section seated, respectively, on the end flaps laterally against the middle section of the profile node (N) region, at least one of the portions (34a, 34b) of the profile extension provided with the same furostransversal provided in each node (N) of each of the upper and lower flanges for receiving and retaining the respective fixing pins (50). Truss beam according to any one of claims 4 to 7, characterized in that each profile flange incorporates at its free end a small bias towards the plane of the other flap, but inclined outwards. Truss beam according to any one of claims 4 to 8, characterized in that each upper and lower flange comprises two "Z" shaped profiles, arranged side by side, with the tabs defining the respective extreme longitudinal edge of the beam. lattice, arranged coplanarly and facing each other, the transverse holes in each node (N) being drilled in the innermost portions of the intermediate section (24, 34) of each pair of profiles, between which the upper and lower extremities are tapered. respectively of the diagonals (26, 36). Lattice beam according to claim 9, characterized in that each diagonal comprises a "C" shaped profile with its side flaps seated against the innermost mid-section portions of the two forming profiles of each of the upper and lower flanges. 11. TRACKED BEAM, OF A TYPE OF UPPER AND LOWER BLOG (11, 21, 31) AND TWO DIAGONAL ASSEMBLIES (12, 22, 32), THE BONDS (12, 22, 32) OF A SET BEING ARRANGED BY THE SAME DIFFERENTLY DELAYED DIRECTION of the direction of the diagonals of the other set, said diagonals (12, 22, · 32) having their upper and lower extremities respectively fixed in denó (N) regions of the flanges, said beam being characterized by the fatode of each flange (11, 21, 31) The upper and lower sections shall be provided with at least one vertical alignment of separate transverse furostroms for each set of diagonals by at least one predetermined distance, each diagonal comprising in each of its upper and lower extremities a single through hole. to be aligned with a transverse hole of the upper and lower flanges, respectively, each set of transverse and through furostrans aligned with each other, receiving an upright pin (25A, 35A). Truss beam according to claim 11, characterized in that each of the diagonals sets comprises at least two parallel diagonals, closely adjacent to one another and disposed between adjacent diagonals of the other set of diagonals, with their upper and lower ends fixed. at the same node (N) of the upper and lower flanges, respectively. Lattice beam according to claim 12, characterized in that the transverse holes provided in each node (N) of each of the upper and lower flanges are spaced apart by a predetermined distance (dl, d2) to allow the attachment of diagonals. different lengths in the upper and lower flanges, latticed trusses with different heights. 14. TRAINED BEAM, of a type comprising an upper and lower flange (11, 21, 31) and two diagonal assemblies (12, 22, 32), the diagonals (12, 22, 32) are arranged in an angularly offset direction relative to another, said diagonals (12, 22, 32) having their upper and lower extremities respectively fixed in regions of knots (N) of the flanges, said beam is characterized by the fact that each of the upper and lower flanges (11, 21, 31) is provided with at least one furotransverse, for each set of angularly-offset diagonals, each diagonal comprising, at each of its upper and lower ends, a single fascia to be aligned with a transverse hole of the upper and lower flanges, respectively, the overlapping and forward diagonals. fixed through the passing transverse holes, aligned with each other, receiving and holding a fixing pin (25A, 35A). Lattice beam according to Claim 14, characterized in that the transverse holes provided in each node (N) of each of the upper and lower flanges are spaced from each other by a predetermined distance (d2) to allow the fixing of differing diagonals. lengths in the upper and lower flanges, lattice trusses having different heights.