GB2268764A - Roof structure with movable support columns - Google Patents

Abstract

A building structure comprises a roof frame of peripheral main beams (11) and at least one main cross beam (12). The main beams support a roof-frame structure (36) and are themselves supported on peripherally arranged upright support columns (13). At least one internal support column (15) is provided away from the periphery. Each internal column (15) is carried on a foundation pad (17) and supports a cross beam or beams in a manner which permits detachment therefrom. The foundation pad (17) for each internal column is made capable of supporting the required load of its column over a range of positions and the roof frame is capable of support over a range of internal column positions to accommodate movement of the support column (15), so that its position may be adjusted after the construction of the building has been completed, e.g. movement up to 1.5m may be possible to allow reorganisation of the buildings internal fittings. <IMAGE>

Description

ROOF STRUCTURES The present invention relates to building structures and in particular to support arrangements for roof structures in buildings.

GB-A-2054694 discloses a modular roof structure in the form of a space frame. An advantage of a roof structure of this form is that a large area may be covered with only peripherally positioned upright support columns, so as to provide a large uninterrupted floor space under the roof. Structures of this form typically cover areas up to 27 m by 18 m for commercial or retail buildings, although larger areas could be spanned if cost is not critical.

For larger areas than can be spanned by a given roof structure, it is necessary to incorporate one or more internal support columns within the area covered by the roof. This can be inconvenient as the upright supports within the area covered by the roof may interfere with the desired positioning of partitions or fittings such as retail sales display units within the building. While the roof and the building may be designed with the internal column position or positions specifically for a particular arrangement of interior partitions and/or fittings to avoid such problems, the same column positions may interfere with proposed changes to the layout of the interior of the building.

According to one aspect of the present invention a building structure comprises a roof frame of peripheral main beams and at least one main cross beam, the main beams being adapted to support a roof structure, the main beams being supported on peripherally arranged upright support columns and at least one internal support column being provided away from the periphery, each internal column being carried on a foundation pad and supporting a cross beam or beams in a manner which permits detachment therefrom, the foundation pad for each internal column being capable of supporting the required load of its column over a range of positions and the roof frame being capable of support over a range of internal column positions to accommodate movement of the support column, so that its position may be adjusted after the construction of the building has been completed.

Reference to the periphery of a structure or to peripheral beams or columns is intended to distinguish the periphery of this particular structure from its interior. It would of course be possible to build outward from this periphery, for example with an entrance foyer or an adjacent building in some respects joined to the building under consideration.

Typically an internal column is positioned at an intersection of two cross beams and its position is adjustable in any of four orthogonal directions along a cross beam. Alternatively an internal column could support a single cross beam and be movable along its length.

Preferably, the main beams comprise upper and lower chords interconnected and spaced apart by spacing members.

The invention is now described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a partially constructed building structure in accordance with the present invention; Figure 2 is an enlarged view of a cross beam and its support columns used in the building structure illustrated in Figure 1; and Figure 3 is an enlarged view of the intersection of two cross beams and an internal support column used in the building structure illustrated in Figure 1.

As illustrated in Figure 1, a building structure comprises a main rectangular roof frame formed by four main beams 11 with its area divided into four by means of main cross beams 12. The main beams 11 and 12 are supported by means of peripheral upright support columns 13 which are positioned around but just outside the rectangular frame 10. The columns are mounted on foundation pads 14. An internal support column 15 supports the cross beams 12 at their point of intersection 16. The internal column 15 is mounted on a foundation pad 17. Peripheral columns 13 are double columns braced together to provide lateral stability while internal column 15 is a single column giving vertical support only.

As illustrated in greater detail in Figures 2 and 3, the main beams 11 and 12 are formed from upper and lower chords 20, 21 of "I" section which are secured together in spaced parallel relationship by means of spacing members 22. Brackets 25 are provided adjacent the ends of cross beams 12, the brackets 25 extending laterally and corresponding in position to the upper and lower chords 20, 21 of the main beams 11, to provide means for bolting the main beams 11 to the cross beams 12. At the point of intersection 16 of the cross beams 12, an upper column section 30 has bracket formations 31 corresponding to the upper and lower chords 20, 21 of the cross beams 12, by which the cross beams 12 may be bolted to the column section 30 in orthogonal positions.The main beams 11 and 12 also have brackets 35 which extend laterally from the upper and lower chords 20, 21 at positions corresponding to the positions of the spacing members 22. The brackets 35 provide means for securing a space frame structure 36 (Figure 1) in the areas defined between the main beams 11 and 12. The space frame 36 is preferably formed from upper and lower planar grids 37, 38 with spacing members 39 extending therebetween, the upper and lower grids 37 and 38 lying in the planes of the upper and lower chords 20 and 21 of the main beams 11 and 12. The space frame 36 may be of modular construction, for example as formed in accordance with GB 2054694.

A plate 40 is secured to the lower end of the upper column section 30. The upper end of the internal support column 15 has a similar plate 41 by which the support column 15 may be secured to the plate 40 in a suitable manner, for example by bolting. A similar plate 42 is also provided at the lower end of support column 15 by means of which it may be secured to the foundation pad 17 in suitable manner. The foundation pad 17 is of extended area in comparison to the foundation pads 14, in order to permit variation in the location of the support column 15, as described hereinafter.

The building structure described above is covered by suitable cladding means, the roof cladding being supported by the space frame 36.

With the building structure described above, if the support column 15 interferes with the internal positioning of partitions or fittings of the completed building due to a changed plan for the layout of the interior of the building, it is possible to move this column away from the point of intersection 16 of the cross beams 12 in any orthogonal direction corresponding to the direction of the cross beams 12. In the detail design of the structure of a building of this general layout, it is possible to provide for the roof structure to be supported satisfactorily over a range of positions of the internal column 15 without changes to other parts of the structure. This would require no more than minor strengthening of the original cross beams or when standardised beam depths and cross sections are employed for peripheral beams and cross beams, satisfactory reserves of strength may be available automatically.

Typically movement of the order of 1.5 m may be accommodated in any direction.

In order to provide for the foundation pad 17 to support the column effectively over a range of positions it has to be enlarged compared with a pad intended for a single point load. The fact that the column 15 applies only vertical loads as opposed to the lateral stabilising loads to be accommodated by peripheral columns reduces the enlargement needed as compared with the foundation pads for peripheral columns.

In order to move column 15 it is released by removing the fastening means by which plate 41 is secured to plate 40 and plate 42 is secured to the foundation pad 17. A temporary load bearing prop is installed between the foundation pad 17 and a cross beam 12 at a position which does not interfere with the required movement of the column 15. The prop is extended slightly, for example hydraulically, to take load off the column 15. Of course the prop requires a suitable bearer pad for engagement with the beam 12 to avoid local overstressing. An additional plate corresponding to plate 40 is then installed under a beam 12 at the desired new positions of the column 15. The column 15 is then moved to the desired position, plate 41 is secured to the new plate and plate 42 secured to the foundation pad 17 in its new position.The temporary prop is then retracted so that the load is transferred to the column 15 in its new position. Column movement can thus be effected simply and quickly and only a minor amount of making good of floor coverings and ceiling is required subsequently.

In general it is not necessary to move the upper column section 30 because the column load can be transferred between lower and upper chords at a point offset from the main part of the column. However, if necessary in some cases, depending on loadings involved, an additional upper column section or additional bracing may be provided between lower and upper chords. As an alternative, the upper column section 30 in the original structure may be replaced by additional distributed bracing between lower and upper chords.

While in the above embodiment, the main beams 11 are bolted to the cross beams 12, cross beams 12 are bolted to the upper column section 30 and the space frame 36 is bolted to the main beams 11 and cross beams 12, any suitable means, for example riveting or welding, may alternatively be used.

A more typical building than that illustrated may have several internal columns, partly because of the size of the building and partly because it may not be a simple rectangular shape and the layout may call for more internal columns. All of these columns may be made moveable in the same way as column 15.

Claims (5)

1. A building structure comprising a roof frame of peripheral main beams and at least one main cross beam, the main beams being adapted to support a roof structure, the main beams being supported on peripherally arranged upright support columns and at least one internal support column being provided away from the periphery, each internal column being carried on a foundation pad and supporting a cross beam or beams in a manner which permits detachment therefrom, the foundation pad for each internal column being capable of supporting the required load of its column over a range of positions and the roof frame being capable of support over a range of internal column positions to accommodate movement of the support column, so that its position may be adjusted after the construction of the building has been completed.

2. A building structure as claimed in Claim 1 wherein an internal column is positioned at an intersection of two cross beams and its position is adjustable in any of four orthogonal directions along a cross beam.

3. A building structure as claimed in Claim 1 wherein each main beam comprises upper and lower chords interconnected and spaced apart by spacing members.

4. A building structure as claimed in Claim 3 wherein an upper column section extends between upper and lower chords.

5. A building structure substantially as described with reference to and as illustrated by the accompanying drawings.