TECHNICAL FIELD

[0001] The present disclosure broadly relates to the field of building construction, and in particular, to a joint structure, to a method of forming at least a part of a joint structure, and to a structural member obtained by such method.

BACKGROUND

[0002] In building construction, and in particular in steel and steel composite structures, load bearing constructions are often created using elongate structural members which are interconnected with each other as well as to other parts of the construction to safely transfer loads to the supports, e.g. to the foundations. Such elongate structural members are, depending on their statical function in the load bearing structure, sometimes referred to as columns, beams, girders, diagonals, etc., or, when summarised in larger assemblies, as portal frames, trusses, orthotropic plates, etc.. In steel structures, the elongate structural members may typically be formed as hot-rolled, welded, and/or cold-formed profiles.

[0003] The manufacturing of hot-rolled profiles involves forming steel from its molten state into the desired shape and requires a proper production line for each type of profile, e.g. I, T, U, or L-shaped cross-section, and size, which is why this type of profile is only available in a limited number of standard configurations. As a result, it is not always possible to achieve a minimum weight in a structure that is solely constructed using hot-rolled profiles. Also, since hot-rolled profiles are designed to cover a broad market of typical applications in the industry in order to amortise the manufacturing costs, they may not always provide a feasible solution in unconventional designs. Finally, hot-rolled profiles are typically not available as tapered beams, i.e. sections that comprise variable cross-sections along their longitudinal axis.

[0004] Profiles with welded cross-sections provide an alternative in cases when hot- rolled profiles are deemed less suitable or not flexible enough. Notably, welded crosssections can be made in a wide range of open and closed cross-sections with constant or varying dimensions along the longitudinal axis of the profile. Because they may be tailor- made, welded profiles usually offer good opportunities to optimise a construction in terms of weight and material effort. However, their manufacture is complex and costly. This aspect relates to, for example, the requirement of employing highly skilled staff to effect the welding as well as the supervision and quality assurance thereof. In the typical case where fusion welding is applied, additional considerations may be necessary in relation to detrimental effects of the heat input in more complex materials like high-strength steel, and potential problems related to fatigue (notch effect of the welding seam).

[0005] Some of the above issues can be avoided when cold-formed profiles are applied, which may be formed from a single sheet blank under plastic deformation thereof (“folding”) along the longitudinal axis of the profile. When compared to hot-rolling or welding, the technical effort required for cold-forming sheet blanks is relatively low, which in combination with the possibility to produce custom- designed profiles allows for cost-efficient solutions. However, cold-forming can become challenging with increasing material thickness and higher steel grades due to increasing resistance to deformation. Therefore, flange and web thicknesses of cold-formed profiles cannot be designed with the same freedom as when welded profiles are used. To compensate for the lower material thickness and to avoid cross-sectional deformations and warping under load, stiffeners may be used along the longitudinal axis of the profile, and/or cross-sections that have almost closed cells may be designed.

[0006] However, joining of such profiles with closed or semi-closed cells, for example in a frame corner or apex configuration, is usually challenging. Because welding is not desirable in cold-formed profiles due to the heat introduction in the plastically deformed regions of the profiles, which may have detrimental effects on material strength and durability, bolted connections are often the designer’s first choice. However, in cases where the cross-section offers limited access on-site for the application of threaded nuts, bolted connections are not always a feasible solution, which is why self-tapping screws are often used as an alternative. These in turn do not offer the same level of strength and robustness as bolted or welded connections, and tend to introduce a rather brittle failure mode of the joint (“unbuttoning”), especially under cyclic loading or large movements of the joint.

[0007] For the above reasons, there seems to be a prejudice in the art that the application of cold-formed sections is limited to small structures and/or structures exposed to low loads, and that joints of cold-formed profiles are limited to lower force levels and/or are not as robust under cyclic loading as joints of hot-rolled or welded profiles.

[0008] It is an object of the present invention to provide an improved joint structure, a method to form at least a part of a joint structure, and a structural member obtained from such method, or to overcome the above shortcomings or address the above desiderata, or to at least provide the public with a useful choice.

SUMMARY [0009] In a first aspect the present disclosure may provide a joint structure comprising: a first and a second structural member, each structural member comprising a cross-section defining an inner surface of the respective structural member; at least a first fixing plate extending along at least a part of the first and second structural members; at least two threaded bolts extending through corresponding apertures in the first fixing plate and corresponding apertures in each of the first and second structural members, each of the bolts thread-wise engaging a corresponding threaded nut secured to the respective inner surface of the respective structural member.

[0010] In a another aspect the present disclosure may provide a joint structure comprising: a first and a second structural member, each structural member comprising a hollow cross-section defining at least a first wall, and an inner surface and an outer surface of the respective structural member; at least a first fixing plate extending along at least a part of a respective end portion of each of the first and second structural members, and adjacent the respective outer surfaces thereof; a plurality of threaded bolts, each one of the plurality of threaded bolts extending through a corresponding one of a plurality of apertures in the first fixing plate and a corresponding one of a plurality of apertures in the respective first wall of each of the first and second structural members, each one of the plurality of threaded bolts thread-wise engaging a corresponding one of a plurality of threaded nuts secured to the respective inner surface of the respective structural member at a location corresponding to the respective aperture in the respective first walls.

[0011] In a another aspect the present disclosure may provide a joint structure comprising: a first and a second structural member, each structural member comprising a hollow cross-section defining at least a first wall, and an inner surface and an outer surface of the respective structural member; at least a first fixing plate extending along at least a part of a respective end portion of each of the first and second structural members, and adjacent the respective outer surfaces thereof; a plurality of threaded bolts, each one of the plurality of threaded bolts extending through a corresponding one of a plurality of apertures in the first fixing plate and a corresponding one of a plurality of apertures in the respective first wall of each of the first and second structural members, each one of the plurality of threaded bolts thread-wise engaging a corresponding one of a plurality of threaded nuts secured to the respective inner surface of the respective structural member at a location corresponding to the respective aperture in the respective first wall, such that the first fixing plate holds the first and second structural members in a pre-determined position relative to each other and transfers forces and moments between the first and second structural members.

[0012] In another aspect, the present disclosure may provide a method of forming at least a part of a joint structure, comprising the steps of: S1 . Providing at least a first and a second sheet blank to create flat projections of corresponding first and second profiles;

52. In a pre-determined pattern, forming a plurality of apertures at end portions of the respective first and second sheet blanks;

53. Cold-forming the first and second sheet blanks to create the first and second profiles, each of the first and second profiles having an open cross-section;

54. Securing a plurality of threaded nuts to a first surface of each of the first and second profiles, such that each one of the plurality of nuts protrudes from the first surface at a location of a corresponding one of the plurality of apertures, and is configured to receive a corresponding threaded bolt inserted through the respective one of the plurality of apertures;

55. Nesting the first and second profiles into each other to create a first structural member comprising a hollow cross-section defining at least a first wall, an inner surface, and an outer surface of the first structural member, wherein the nesting is performed such that the plurality of threaded nuts is located at the inner surface and within the hollow cross-section of the first structural member.

[0013] In another aspect, the present disclosure may provide a method of forming a structural member, comprising the steps of:

51 . Providing at least a first and a second sheet blank to create flat projections of corresponding first and second profiles;

52. In a pre-determined pattern, forming a plurality of apertures at end portions of the respective first and second sheet blanks;

53. Cold-forming the first and second sheet blanks to create the first and second profiles, each of the first and second profiles having an open cross-section;

54. Securing a plurality of threaded nuts to a first surface of each of the first and second profiles, such that each one of the plurality of nuts protrudes from the first surface at a location of a corresponding one of the plurality of apertures, and is configured to receive a corresponding threaded bolt inserted through the respective one of the plurality of apertures;

55. Nesting the first and second profiles into each other to create a first structural member comprising a hollow cross-section defining at least a first wall, an inner surface, and an outer surface of the first structural member, wherein the nesting is performed such that the plurality of threaded nuts is located at the inner surface and within the hollow cross-section of the first structural member.

[0014] The following configurations may relate to any of the above aspects.

[0015] In one configuration, each of the first and second structural members comprises cold-formed first and second profiles, the respective first and second profiles nested into each other to define the respective hollow cross-section.

[0016] In one configuration, each of the first and second profiles comprises a C-shaped cross-section.

[0017] In one configuration, each of the first profiles is secured to the respective second profile along at least a part of a length thereof by at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, submerged arc (SAW) welding, tungsten inert gas (TIG) welding, laser welding, brazing, soldering, and/or using an adhesive.

[0018] In one configuration, the plurality of threaded nuts is secured to the respective inner surface of the respective first and second structural member by at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, tungsten inert gas (TIG) welding, friction welding, laser welding, brazing, soldering, diffusion bonding, and/or using an adhesive.

[0019] In one configuration, each of the first and second structural members comprises a second wall, wherein a second fixing plate is attached to the first and second structural members by a plurality of threaded bolts extending through a corresponding one of a plurality of apertures in the second fixing plate and a corresponding one of a plurality of apertures in the respective second wall of each of the first and second structural members, each one of the plurality of bolts thread-wise engaging a corresponding one of a plurality of threaded nuts secured to the respective inner surface of the respective structural member at a location corresponding to the respective aperture in the respective second wall.

[0020] In one configuration, the first and second fixing plates extend in parallel at opposing sides of each of the first and second structural members, such that the first and second fixing plates hold the first and second structural members between them.

[0021] In one configuration, the hollow cross-sections of each of the first and second structural members have a first height parallel to a main load-bearing direction of the first and second structural members, wherein the first fixing plate, and any second fixing plate, is attached to each of the first and second structural members across substantially the whole of the first height thereof.

[0022] In one configuration, the plurality of bolts comprises an identical or at least similar number of bolts assigned to each of the first and second structural members, arranged in a bolt pattern suitable for transferring bending moments, torsional moments, sheer forces, and normal forces between the first and second structural member.

[0023] In one configuration, each of the first and second structural members comprises an end plate welded or otherwise connected to an end section of the respective structural member at a portion thereof where a joint with the respective other of the first and second structural members is formed.

[0024] In one configuration, each end plate has a shape substantially identical to the respective hollow cross-section at the end section, and is continuously welded to the corresponding one of the first and second structural members along a periphery of its crosssection.

[0025] In one configuration, the hollow cross-section of each structural member comprises a maximum clearance dimension h _ma x wherein the plurality of bolts is distributed along a major axis of each of the first and second structural members along a distance d parallel to a main bearing direction of each of the first and second structural members, a relationship between the maximum clearance dimension h _ma x and the distance d being defined by hmax < d < 10-h max, and preferably by 2 ■ hmax — d — 5‘ hmax-

[0026] In one configuration, the first and second structural components are arranged in one of an apex joint or frame corner configuration, wherein respective major axes of the first and second structural members are arranged in a common plane and at an angle to each other.

[0027] In one configuration, the step S4 of securing the plurality of threaded nuts to the first surface of each of the first and second profiles comprises applying at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, tungsten inert gas (TIG) welding, friction welding, laser welding, brazing, soldering, diffusion bonding, and/or using an adhesive.

[0028] One configuration comprises the step S6 of securing the first and second profiles to each other at adjacent surfaces and along a length-wise direction thereof.

[0029] In one configuration, the step S6 of securing the first and second profiles to each other comprises applying at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, tungsten inert gas (TIG) welding, friction welding, laser welding, brazing, soldering, diffusion bonding, and/or using an adhesive.

[0030] One configuration comprises the step S7 of securing, preferably by welding, a corresponding end plate to at least one end of the hollow cross-section of the first structural member, to form a closed end of the first structural member.

[0031] One configuration comprises the steps of:

58 Performing at least steps S1 to S5 and, preferably, steps S6 to S7, to thereby form a second structural member;

59 Positioning the first and second structural members in a desired position relative to each other;

510 Providing at least a first fixing plate extending along at least a part of a respective end portion of each of the first and second structural members, and adjacent their respective outer surfaces, the at least first fixing plate comprising a plurality of apertures corresponding to the plurality of apertures in the first and second structural members;

511 Inserting a plurality of bolts through the plurality of apertures in the at least one fixing plate and the corresponding apertures in the at least first wall of each of the first and second structural members, such that each one of the plurality of bolts engages with and is threadwise secured to a respective one of the plurality of threaded nuts.

[0032] In one configuration, step S10 comprises providing a second fixing plate parallel to the first fixing plate such that the first and second structural members are held between the first and second fixing plates, the second fixing plate comprising a plurality of apertures corresponding to a plurality of apertures in the first and second structural members; and step 11 comprises inserting a plurality of bolts through the plurality of apertures in the second fixing plate and the corresponding apertures in the at least first wall of the first and second structural members, such that each one of the plurality of bolts engages with and is thread-wise secured to a respective one of the plurality of threaded nuts.

[0033] In one configuration, step S9 of positioning the first and second structural members in a desired position relative to each other comprises positioning the first and second structural members in one of an apex joint or frame corner configuration, wherein respective major axes of the first and second structural members are arranged in a common plane and at an angle to each other. [0034] The term “comprising” as used in the specification and claims means “consisting at least in part of.” When interpreting each statement in this specification that includes the term “comprising,” features other than that or those prefaced by the term may also be present. Related terms “comprise” and “comprises” are to be interpreted in the same manner.

[0035] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 shows a joint structure according to an embodiment of the invention.

[0037] Figures 2 to 7 show the manufacturing of a structural member and, respectively, of a joint structure according to an embodiment of the invention.

DETAILED DESCRIPTION

[0038] Described is a joint structure 1 comprising: a first 100 and a second structural member 200, each structural member 100, 200 comprising a cross-section defining an inner surface of the respective structural member; at least a first fixing plate extending along at least a part of the first and second structural members; at least two threaded bolts extending through corresponding apertures in the first fixing plate and corresponding apertures in each of the first and second structural members, each of the bolts thread-wise engaging a corresponding threaded nut secured to the respective inner surface of the respective structural member.

[0039] Embodiments of a joint structure will now be described with reference to Figures 1 through 7.

[0040] Figure 1 shows a joint structure 1 which in this embodiment is a corner of a portal frame. The joint structure 1 comprises a first 100 and a second structural member 200. In the portal frame corner configuration shown in the figure, the first structural member 100 would typically be referred to as a frame column while the second member 200 would be called a rafter. Each structural member 100, 200 comprises a hollow cross-section 105, 205, which in the present case is variable along a respective notional major axis 101 , 201 of the respective structural member 100, 200. As is apparent from the figure, the height of each of the cross-sections 105, 205 changes in a linear fashion along the respective major axis 101 , 201 , and the overall shape of each of the structural members 100, 200 is sometimes referred to as tapered.

[0041] The major axes 101 , 201 of the first 100 and second 200 structural members together define a notional plane P as indicated in Figure 1 . Typically, the joint structure 1 is designed to transfer forces and moments acting in the plane P as well as perpendicular thereto.

[0042] Each hollow cross-section 105, 205 defines a first wall 110, 210 and a second wall 1 10’, 21 O’, as well as an inner surface 107, 207 and an outer surface 109, 209 of the respective structural member 100, 200. While the embodiments shown in the figures comprise first walls 110, 210 as well as second walls 1 10’, 21 O’, embodiments exist with less as well as with more walls and surfaces. For example, in embodiments in which the first 100 and second 200 structural members have circular cross-sections 105, 205, only one first wall 110, 120 in each of the structural members 100, 200 may be identified. Similarly, the skilled person will appreciate that in other embodiments a cross-section of a structural member may define several distinct webs and/or flanges forming distinct walls and/or inner and outer surfaces.

[0043] Joint structure 1 further comprises first 300 and second 400 fixing plates extending along at least a part of a respective end portion 140, 240 of each of the first 100 and second 200 structural members, and adjacent the respective outer surfaces 109, 209 thereof. The first 300 and second 400 fixing plates extend in parallel at opposing sides of each of the first 100 and second 200 structural members in the figure, such that the first 300 and second 400 fixing plates hold the first 100 and second 200 structural members between them. This configuration is advantageous in that each of the webs of the structural members, which in Figure 1 are the parts of structural members 100, 200 which extend in notional planes parallel to the notional plane P, is supported by and can transfer forces through one of the first 300 and second 400 fixing plates. However, it will be appreciated that in some embodiments only one fixing plate 300 may be necessary to transfer the forces between the first 100 and second 200 structural members.

[0044] The first 300 and second 400 fixing plates are designed to hold the first 100 and second 200 structural members in a pre-determined position relative to each other and transfers forces and moments between the first 100 and second 200 structural members. To this end, a plurality of threaded bolts 500 is provided each one of which extends through a corresponding one of a plurality of apertures 320, 420 (not shown in Figure 1 ) in the first 300 and second 400 fixing plates and a corresponding one of a plurality of apertures 120, 220 in the respective first 110, 210 and second 110’, 210’ wall of each of the first 100 and second 200 structural members. Each one of the plurality of threaded bolts 500 thread-wise engages a corresponding one of a plurality of threaded nuts 600 secured to the respective inner surface 107, 207 of the respective structural member 100, 200 at a location corresponding to the respective aperture 320, 420 in the respective first 110, 210 and second 110’, 210’ wall. This design, which will be explained in more detail in relation to figures 2 to 7, provides not only a fast and effective way of securing the first 300 and second 400 fixing plates to the first 100 and second 200 structural members, it also provides advantageous effect with a view to the local stability of the first 110, 210 and second 110’, 210’ walls. In particular, since the plurality of threaded nuts 600 is secured to the inner surface 107, 207 of the respective structural member 100, 200, the plurality of threaded bolts 500 effectively connects the first 300 and second 400 fixing plates directly to the respective first 110, 210 and second 110’, 210’ wall. In statical terms, this effectively increases the thickness of the respective first 110, 210 and second 110’, 210’ wall in the area of the respective first 300 and second 400 fixing plates, which helps restricting a phenomenon known as local plate buckling which must always be considered in corners of portal frames.

[0045] Turning to Figures 2 to 7, a method of forming the structural member 100 for use in the joint structure 1 , as well as a method of forming the joint structure 1 will now be described. The method comprises the step S1 of providing at least a first 12 and a second 22 sheet blank to create flat projections of corresponding first 10 and second 20 profiles. The first 12 and second 22 sheet blanks may be fabricated using a computer numerical control (CNC) process like CNC cutting, or any other suitable process.

[0046] Step S2 comprises forming the plurality of apertures 120, 220 at respective end portions 141 , 241 of the respective first 12 and second 22 sheet blanks for example by drilling and/or by using a CNC process. The pattern in which the plurality of apertures 120, 220 is applied is typically determined dependent on the forces and moments which have to be transferred by the joint structure 1 . As the plurality of apertures 120, 220 is applied in the flat first 12 and second 22 sheet blanks, the method disclosed herein provides the designer with a high degree of freedom in the arrangement of the plurality of apertures 120, 220.

[0047] Turning to Figure 3, in a step S3, the first 12 and second 22 sheet blanks are turned into the first 10 and second 20 profiles by a cold-forming process, for example by folding or rolling. As shown in Figure 3, each of the first 10 and second 20 profiles has an open cross-section which in the Figure is a basically C-shaped cross-section. Other cross- sectional shapes may be chosen, for example U- of L-shaped cross-sections, or semicircular cross-sections. In the example shown in Figure 3, the first 10 and second 20 sections are tapered, with a height H at one end of the section 10, 20 being greater than a corresponding height h at the opposite end. This configuration may be chosen when in the finished structure under loading, the internal forces on one end of the section 10, 20 are greater than on the other end. Providing a taper in the first 10 and second 20 sections thus helps to efficiently use the resistance of the cross-sections on each end, which as a result yields material savings. The freedom to design the first 10 and second 20 profiles with such considerations in mind, while keeping manufacturing costs at a low level, is one of the advantages of cold-forming.

[0048] It is noted that, while Figure 3 shows first 12 and second 22 sections which are rather compact, these sections may be much more slender, wherein a ratio between a length L and a height H as indicated in Figure 3 may typically be in the range of 5 < L/H < 50, depending on statical requirements.

[0049] With reference to Figure 4, a step S4 of the method described herein comprises securing the plurality of threaded nuts 600 to a respective first surface 14, 24 of the first profile 10 and, respectively, the second profile 20. The plurality of threaded nuts 600 is secured to the first surfaces 14, 24 such that each one of the plurality of nuts 600 protrudes from the respective first surface 14, 24 at a location of a corresponding one of the plurality of apertures 120, 220, and is configured to receive a corresponding one of the plurality of threaded bolts 500 inserted through the respective one of the plurality of apertures 120, 220. In other words, an inner aperture of each one of the plurality of threaded nuts 600 forms an extension of a corresponding one of the plurality of apertures 120, 220. While in Figure 4 only one end region of the first profile 10 is shown, step S4 is carried out for all of the plurality of apertures 120, 200 created in the first 10 and the second 20 profiles in step S2. Step S4 is, in some embodiments, preformed subsequent to step 3.

[0050] As has been discussed in relation to Figure 1 above, each of the plurality of threaded nuts 600 receives and engages with one of the plurality of threaded bolts 500 in an assembled state of the joint structure 1 , in order to transfer loads between one of the first 100 and second 200 structural members, one or both of the first 300 and second 400 fixing plates, and the respective other one of the first 100 and second 200 structural members. Therefore, and as the skilled person will appreciate, it is crucial that each one the plurality of threaded bolts 500 engages the respective one of the plurality of threaded nuts 600 with a particular prescribed torque. For this prescribed torque to be established, however, it is necessary that a bond between the plurality of threaded nuts 600 and the respective first surface 14, 24 is sufficiently strong to withstand that torque as well. Therefore, in some embodiments, the step S4 of securing the plurality of threaded nuts 600 to the first surface 14, 24 of each of the first 10 and second 20 profiles comprises applying at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, tungsten inert gas (TIG) welding, friction welding, laser welding, brazing, soldering, diffusion bonding, and/or using an adhesive at an interface between the first surfacel 14, 24 and each of the plurality of threaded nuts 600.

[0051] The method disclosed herein comprises a step S5 of nesting the first 10 and second 20 profiles into each other to thereby create the first structural member 100. Step S5, which is represented in the cross-sectional view of the first structural member 100 in Figure 5, is preferably performed subsequent to step S4. As described in some detail above with reference to Figure 1 , the first structural member 100 comprises the hollow cross-section 105, which in Figure 5 is parallel to the drawing plane, and defines the first wall 110, the second wall 110’, an inner surface 107, and an outer surface 109 of the first structural member 100. The nesting is performed such that the plurality of threaded nuts 600 is located at the inner surface 107 and within the hollow cross-section 105 of the first structural member 100. In other words, the cold-forming and nesting are coordinated such that the first surfaces 14, 24 of the first 10 and second 20 profiles becomes the inner surface 107 of the first structural member 100.

[0052] As will be clear in the light of the above explanation, the method as defined by steps S1 to S5 may be used to create a structural member 100. In order to provide the structural member 100 with more stiffness and robustness, the method may further comprise step S6 of securing the first 10 and second 20 profiles to each other at adjacent surfaces and along a length-wise direction. The length-wise direction is depicted in Figure 2 as dotted line x runs parallel to the major axis of the structural member 100. In Detail A of Figure 5, which shows an enlarged area of the upper left corner of the cross-section of the first structural member 100, a welding seam 30 fulfils the function of securing the first 10 and second 20 profiles to each other.

[0053] The welding seam 30 may run continuously along the length-wise direction or may be an intermittent weld. It should also be noted that while a fillet weld is shown in the figure, other variations of welding seams may be applied, e.g. a keyhole weld through the upper surface of the second profile 20 and through the first profile 10 as indicated by line Lw in Detail A. In more general terms, the step S6 of securing the first and second profiles to each other comprises applying at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, tungsten inert gas (TIG) welding, laser welding, friction welding, brazing, soldering, diffusion bonding, and/or using an adhesive.

[0054] As can be seen in Figure 6, first 160 and second 170 end plates may be welded to end portions 140 and 150 of the structural member 100 to prevent the open cross-section from deforming under load and provide it with additional stiffness in a step S7. The step S7 may comprise applying at least one of the processes of welding, metal inert gas (MIG) welding, metal active gas (MAG) welding, stick welding, tungsten inert gas (TIG) welding, laser welding, friction welding, brazing, soldering, diffusion bonding, and/or using an adhesive.

[0055] As the skilled person will be aware, and as will be described in some more detail in the following under reference to Figure 7, the method disclosed above can also be applied for forming a joint structure 1 . To this end, steps S1 to S5 and, preferably, steps S6 to S7, are performed to form another structural member, in the following example the second structural member 200, which may be referred to as another step S8. In order to form the joint structure 1 , the first 100 and second 200 structural members may be positioned in a desired position relative to each other. This step is herein referred to as step S9. In Figure 7 the first 100 and second structural 200 members are positioned to form an apex joint.

[0056] In step 10, the first 300 and second 400 fixing plates are provided. As also explained with reference to the joint structure 1 shown in Figure 1 above, the first 300 and second 400 fixing plates transfer forces and moments between the first 100 and second 200 structural members and extend along at least a part of a respective end portion 140, 240 of the first 100 or, respectively, second 200 structural members. To this end, the first 300 and second 400 fixing plates exhibit a plurality of apertures 320, 420 corresponding to the plurality of apertures 120, 220 in the first 100 and second 200 structural members, as shown in Figure 7.

[0057] In step 11 , the plurality of bolts 500 is inserted through the plurality of apertures 320, 420 in the first 300 and second 400 fixing plates and the corresponding apertures 120, 220 in the first 110, 210 and second 110’, 210’ walls of each of the first 100 and second 200 structural members. As can be seen in Figure 7, each one of the plurality of bolts 500 is relatively short as it is configured to engage with and be thread-wise secured to a respective one of the plurality of threaded nuts 600 pre-installed to the inner surfaces 107, 207 of the first 100 and second 200 structural members. There is hence no need to feed each single one of the plurality of bolts 500 through the whole width of each of the first 100 and second 200 structural members as is the case in some prior art solutions, which is beneficial with a view to a simpler assembly. In addition thereto, each one of the plurality of bolts 500 clamps the respective fixing plate 300, 400 to the respective first 110, 210 or second 110’, 210’ wall, thereby creating an effectively thicker wall thickness of the first 100 and second 200 structural members in the area of the joint structure 1 . This is advantageous in relation to local buckling phenomena which is less likely to occur in the present joint structure 1 than in some comparable prior art solutions. [0058] It will be understood that the configuration of the joint structure 1 in which the plurality of nuts 600 is arranged inside the hollow cross-section 105, 205 of the respective structural member 100, 200 allows for a very convenient assembly of the joint structure 1 because there is no requirement for the assembly staff to reach the inside of the structural members 100, 200 to secure the plurality of bolts 500. According to an aspect related thereto, the joint structure 1 according to the present disclosure provides for a high degree of freedom in the design of a suitable bolt pattern in which the plurality of bolts 500 is arranged. While there is basically no limitation in relation to how far from any open end of the structural members 100, 200 a nut may be arranged inside the respective hollow cross-sections 105, 205, an exemplary bolt pattern will now be described in more detail with reference to Figure 7.

[0059] Assuming that the cross-section of each of the structural members 100, 200 comprises a maximum clearance dimension h _ma x in the area of the joint structure 1 . With reference to Figure 3, this maximum clearance dimension h _ma x corresponds substantially to one of the heights H or, respectively, h. As can be taken from Figure 7, the plurality of bolts 500 is distributed along a major axis of each of the first 100 and second 200 structural members along a distance d parallel to a main bearing direction of each of the first 100 and second 200 structural members. In the joint structure 1 disclosed herein, a relationship between the maximum clearance dimension h _max and the distance d may have values of, for example, in the range of h _max < d < 10-h _max , and preferably by 2 ■hmax — d — 5‘hmax-

[0060] In absolute values, the distance d may be in the range of, for example, 500 mm, 1000 mm, 1500 mm, 2000 mm, or 3000 mm without requiring awkward assembly tools and/or techniques.

[0061] Similarly, as it is not required during assembly to reach the inside of one of the first 100 and second 200 structural members, first 160 and second 170 end plates as shown in Figure 6 may be used and pre-assembled to the first 100 and second 200 structural members before assembly of the joint structure 1 , without any implications or restrictions in relation to the ease of assembly of the joint structure 1 .

[0062] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

[0063] Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention as herein described with reference to the accompanying drawings.