SPACE FRAME AND MODULE FOR ITS CONSTRUCTION

Abstract: A space frame comprises an upper rectangular grid of horizontal structural members (21B to 24B) and a corresponding lower grid of horizontal structural members (21A to 24A). Upper and lower grids are interconnected by upright members (25A, 25B) at intersections. The structure is built up from prefabricated modules (A, B, etc.) each of which comprises one upright member and four orthogonally arranged horizontal members (21 to 24). Alternate modules (B) are inverted and the outer ends of horizontal members (21A, 21B) are fixed to the free ends (31B, 31A) of the upright members (25).

Description: SPACE FRAME AND MODULE FOR ITS CONSTRUCTION The invention relates to space frames, particularly but not exclusively for use as horizontal structures bridging spaces between supports. A space frame is especially suitable for covering a substantial space with support only at the edges, the structure being otherwise self-supporting, with no need for intervening upright supports. A space frame commonly comprises upper and lower grids of structural members, joined by interconnecting members to form a rigid three dimensional structure. A space frame is used, for example, for a roof structure where a large space unencumbered by upright supports is important. It can also be used for the floors and roof of a multi-storey office block. A space frame can also be used as a temporary structure such as a temporary floor covering a swimming pool or as an out-door stage or roof for such a stage. One form of space frame is described in our own earlier Patent GB-B-2054694. This structure has upper and lower grids of horizontal structural members interconnected by upright structural members at intersections of the upper and lower grid members. The complete space frame is built up from a series of modules each comprising one upright member and horizontal upper and lower structural members. Modular construction is attractive because much of the assembly work can be carried out in factory conditions and the modules merely require joining together on site. Each module is normally constructed by welding the various elements together in a jig. When the required depth between the upper and lower layers is comparatively small, for example less than one metre, full access to the joints with welding equipment becomes difficult, due to the presence of horizontal members at the other end of the upright member and due to the presence of the jig. An object of the present invention is to overcome this difficulty. According to the present invention a space frame comprising an upper grid of horizontal structural members joined together at upper intersections, a lower grid of horizontal structural members joined together at lower intersections and upright structural members interconnecting the grids at their intersections, the structure being formed from prefabricated modules, is characterised in that each module comprises one of the upright members and horizontal structural members joined to one end only of the upright member, alternate modules being assembled into the space frame in relatively inverted positions with the free ends of horizontal members of one module each joined to the free end of the upright member of an adjacent module. In addition to simplifying the access to joints for welding during manufacture, these modules can be stacked together more compactly for transportation than the modules of our earlier patent. This facility can make it more attractive to serve a wider geographical area from a single module manufacturing facility. Preferably the upright and horizontal members forming a module are welded together. The invention is particularly useful with a welded construction because good access is available for welding equipment. The horizontal structural members may be I-section steel members. Preferably the horizontal members of one module are joined to adjacent modules by bolts. Each end of a horizontal structural member for joining to another module may incorporate a connector plate secured thereto and extending beyond the end thereof. The free end of the upright member of each module may incorporate a connector comprising vertical plates for joining to the connector plates of horizontal members. The upper and lower grids of horizontal structural members may each be in an orthogonal pattern provided by modules each incorporating four horizontal structural members. Diagonal braces may be provided, extending from at least some of the horizontal members to the upright member of the same module. The invention also extends to a module for use in construction of a space frame as set out above, the module being formed as a welded together assembly of an upright structural member and horizontal structural members, characterised in that all the horizontal structural members are welded or otherwise permanently connected to and extend out from one end of the upright member. An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a diagrammatic perspective view representing a space frame in accordance with the invention; Figure 2 is a perspective view of two modules in appropriate orientations for joining together and with other modules to form a space frame; Figures 3 and 4 are corresponding views of modules employed at edges and corners of the space frame; Figure 5 shows a typical connection of modules with one another; Figure 6 illustrates modi ications to the arrangement of Figure 5; and Figure 7 is a view corresponding to one of the modules of Figure 2, showing a modification. Figure 1 is a diagrammatic representation of a space frame constructed from modules as shown in Figures 2 to 4. The basic structure incorporates an upper orthogonal grid of horizontal structural members 11 which in this example are of equal lengths so that they form a square pattern. There is a corresponding lower grid of horizontal structural members 12 spaced from the upper members 11 by upright structural members 13. An optional feature is the provision of diagonal braces 14. To illustrate the modular construction, those structural members which are joined as a module prior to assembly of the structure are shown as being joined together while in contrast those structural members of one module which in use are joined to structural members of another module are shown separated by small gaps between the members. For example, intersection 15 is a joint in the upper grid between structural members of the same module and intersection 16 is a corresponding lower joint. Similarly, intersection 17 is a connection of several modules in the upper grid and intersection 18 is a corresponding lower connection. Figure 2 illustrates two typical modules A and B. In the following description, suffixes A, B etc refer to the module of which an item is a part. Module A is in what will be referred to as a regular orientation with four horizontal structural members 21A to 24A at its lower end and an upwardly extending vertical structural member 25A. Members 21A to 24A are I-section steel members and member 25A is a square section hollow steel member. Members 21A to 24A have square cut ends and are welded directly to the four faces of the square section member 25A. Member 25A may be closed off by an end plate 26A welded thereto. A reinforcing plate 27A (best seen as 27B in module B) may be a square flat plate with diagonally offset square aperture so that it fits over member 25A (or 25B) and has a corner in contact with each horizontal member. It is then secured by welding both to the vertical member and to the horizontal members. Plate 27 is optional . The free end of each horizontal member, that is the end remote from the welded joint to the upright member, incorporates a connector plate 28 which will be described subsequently in greater detail. The free end of the upright member 25, that is the end remote from the welded joint with its horizontal members incorporates a connector 31 for joining with connector plates 28 of other modules. Details of connector 31 are best illustrated in module B. The end of upright member 25B is closed off by a square plate 32. A cruciform structure of four small vertical plates 33 is formed by welding the plates to one another and to the end plate 32. Each of the four plates making up the cruciform arrangement is adapted to receive and to be joined to a plate 28 from another module. For example, as illustrated, each plate may be provided with a bolt hole so that the components can be bolted together. Module B is shown in the opposite orientation from module A in that the upright member 25 projects downward instead of upward from the four horizontal members 21B to 24B. When joining modules together, horizontal member 24A of module A is joined to connector 31B of module B and similarly horizontal member 22B of module B is joined to connector 31A of module A. It is clear from Figure 1 that modules along the edges of the structure should have only three horizontal members and that modules at the corners should have only two horizontal members. Suitable modules to meet these requirements are illustrated in Figures 3 and 4. Figure 5 shows the connection together of several modules and illustrates in greater detail the connector plates 28 and the connectors 31 on the ends of the upright members. In addition to module A and inverted module B, three other modules C, D and E in the same regular orientations as module A each have a horizontal member joined to this connection. A typical horizontal member 24A from a module A incorporates a connector plate 28A welded to the web of the I-section horizontal member. Plate 28A extends out beyond the end of member 24A and has a central bolt hole 34A. Corresponding parts 22C, 28C, 34C and 23D, 28D, 34D are shown in different orientations for the modules C and D. Corresponding parts 21E, 28E and 34E for a further module E are not illustrated in Figure 5. The horizontal members 24A, 22C, 23D and 21E are secured to end connector 31B of upright member 25B. This connector is shown to comprise an end plate 32B carrying a cruciform arrangement of connector plates 33B, not all of which are shown. Each plate 33B incorporates a bolt hole through which a bolt (not shown) is passed to join the respective horizontal member to the upright member 25. Figure 6 shows two possible modifications for joining connector plates 28 to horizontal structural members where greater strength is required. Plate 28F of Figure 6 is slightly longer than the corresponding plate 28A of Figure 5 and in addition to being welded to horizontal member 21F is bolted to it by a single bolt (not shown). In a further modification the plate 28H is still longer than plate 28F and is bolted to horizontal member 23H by two bolts (not shown) . Figure 7 shows a single module G similar to module A of Figure 1 but also incorporating diagonal braces. Each diagonal brace is a steel member 35 welded to the top surface of its associated horizontal structural member near the outer end thereof and to the corresponding face of the square section upright member 25G near the top thereof. These braces 35 are optional and as illustrated in Figure 1 it may be convenient to provide them at certain locations around the edge of the complete structure, omitting them from other parts of the structure. Thus some modules may have less diagonal braces than they have horizontal members. The resulting structure is relatively strong and light and is easy to assemble on site. It may be assembled by starting from one corner or edge with a module fixed to an appropriate support for the structure and then adding one module at a time. Alternatively some assemblies of groups of modules may be pre-assembled together and then moved into position for connection to other such sub-assemblies. Each module is manufactured in a jig which holds the structural members in their required relative positions. Because the horizontal structural members are provided at only one end of the upright member, good access is available to the joint in all required directions to establish an effective weld. The diagonal braces 35 if required are added subsequently. For rationalisation purposes it is convenient for all modules other than corner and edge modules to be identical to each other and for the corner and edge modules merely to omit one or two horizontal members and incorporate correspondingly modified connectors 31 and reinforcing plates 27. However, in some structures, there may be a requirement for greater strength in the horizontal members in either tjhe. upper grid or the lower grid. For example, the space frame could be used in a composite steel and concrete structure as described in our co-pending European Patent Application No. 90300221.0. With that arrangement, the upper horizontal members may have a smaller cross sectional area than the lower members because the strength of the upper members is supplemented by embedding in concrete. In such a case, two different module designs are required, one for standard orientation and the other for inverted orientation. For some structures, it may be desirable to use a greater spacing between horizontal members in one direction along the length of the structure than in another direction across its width. To achieve such a structure, each module should have unequal length horizontal member. If the structure is to be a cambered or pitched roof, typically with up to a few degrees of pitch or camber for drainage purposes, small variations in angles between members or between lengths of members may be required to achieve the pitch or camber. Such small variations from true vertical and horizontal as occur for the components and the structure as a whole do not affect the fundamental nature of the structure and are intended to be comprehended within general references to vertical and horizontal directions. The cross section and material of the structural members may be varied. For example the uprights could be round tubes. Similarly, horizontal members could be T sections or I sections with unequal flanges. Horizontal members for one direction may differ in section from those in the other direction. Aluminium or some other material could replace steel for specialist applications where weight is critical. In assembly of a module from its components, other forms of permanent attachment besides welding may be used. For example, developments in adhesive technology could allow the use of adhesives in place of welding. It may be desirable with some structures to use some modules which are stronger than other modules. For example, with a square space frame supported only at its corners, it may be desirable for all the edge modules and corner modules to incorporate horizontal members of increased cross section in addition to or in place of providing these modules with braces 35.

Claims: CLAIMS 1. A space frame comprising an upper grid (11) of horizontal structural members (21B, 22B, 23B, 24B) joined together at upper intersections (15), a lower grid (12) of horizontal structural members (21A, 22A, 23A, 24A) joined together at lower intersections (16) and upright structural members (13 or 25) interconnecting the grids at their intersections, the structure being formed from prefabricated modules (A, B etc), characterised in that each module comprises one of the upright members (25) and horizontal structural members (21, 22, 23, 24) joined to one end only of the upright member, alternate modules (A and B etc) being assembled into the space frame in relatively inverted positions with the free ends of horizontal members of one module each joined to the free end of the upright member of an adjacent module. 2. A space frame as claimed in Claim 1 characterised in that the upright (25) and horizontal (21 to 24) members forming a module are welded together. 3. A space frame as claimed in claim 1 or 2 characterised in that the horizontal structural members (21 to 24) are I-section steel members. 4. A space frame as claimed in any one of the preceding claims characterised in that the horizontal members (21A, 22B) of one module are joined to adjacent modules by bolts (bolt holes 34A, 34B) . 5. A space frame as claimed in any one of the preceding claims characterised in that each end of a horizontal member for joining to another module incorporates a connector plate (28) secured thereto and extending beyond the end thereof. 6. A space frame as claimed in claim 5 characterised in that the free end of the upright member of each module incorporates a connector (31) comprising vertical plates (33) for joining to the connector plates (28) of horizontal members. 7. A space frame as claimed in any one of preceding claims characterised in that the upper and lower structural members are each arranged in an orthogonal pattern produced by modules each incorporating four horizontal structural members. 8. A space frame as claimed in any one of preceding claims further comprising diagonal braces (35) extending from at least some of the horizontal members to the upright inember of the same module. 9. A module (A or B) for a space frame as claimed in any one of the preceding claims formed as a welded together assembly of an upright structural member (25) and horizontal structural members (21 to 24) characterised in that all the horizontal structural members are welded or otherwise permanently connected to and extend out from one end of the upright member (25).

Inventors: KUBIK LESZEK ALEKSANDER, KUBIK MARIAN LESZEK, KUBIK, LESZEK, ALEKSANDER, KUBIK, MARIAN, LESZEK
Applicants: KUBIK LESZEK A, KUBIK MARIAN L, KUBIK, LESZEK, ALEKSANDER, KUBIK, MARIAN, LESZEK
Application year: 1990
Main classification: E04B1
IPC codes: E04B1, E04B7, E04C3