GB2212185A

GB2212185A - Structural frames and structures incorporating such frames

Info

Publication number: GB2212185A
Application number: GB8826053A
Authority: GB
Inventors: Richard Mortimere Sewell; Peter Stephen Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-11-07
Filing date: 1988-11-07
Publication date: 1989-07-19
Anticipated expiration: 2008-11-07
Also published as: GB2212185B; GB8726135D0; GB8826053D0

Abstract

A structural frame for bridging a space between supports is assembled from a plurality of modules each of which comprises an upright member 12 having a number of co-planar structural members 10 extending from its lower end, the members 10 of adjacent modules being joined together end-to-end. The spaces between the upper ends of the upright members 12 are bridged by temporary connectors (15 Fig 2) which are used to support shuttering on which a slab (17 Fig 2) of concrete is cast, such that upper ends of the upright members 12 are embedded in the slab 17. <IMAGE>

Description

TITLE: STRUCTURAL FRAMES AND STRUCTURES INCORPORATING SUCH FRAMES This invention relates to structural frames, structures incorporating such frames and a method of erecting such a structure.

In UK patent no. 2054694 there is described a structural space frame for bridging a space between supports which comprises a multiplicity of modules bolted together to form upper and lower planar grids interconnected by substantially orthogonal spacing members. This structural frame is particularly easy to construct, but has not been widely used for multi-storey structures because the cost and weight of the metal involved do not give rise to sufficient advantages over other methods of producing multi-storey buildings.

It is an object of the present invention to provide a structural frame which, while still being relatively simple to construct, is capable of being used for multi-storey constructions.

According to a first aspect of the present invention, a structural frame comprises a generally planar grid forming a bottom of the frame and composed of a plurality of substantially co-planar structural members which meet at nodal points, and upright structural members extending upwardly from the nodal points, each upright member having at least one attachment point at or adjacent its upper end to which a connector can be attached to support shuttering for casting a slab of material, the connector spanning the space between an adjacent pair of said upright members.

Advantageously, each connector is adjustable in length.

Conveniently, the nodal points in each adjacent pair are interconnected by two structural members which are connected together at a location intermediate those points, preferably substantially half-way between thuse points.

Desirably, each upright member has keying means (which may be in the form of at least one lateral projection) at or adjacent its upper end, the keying means being incorporated into the cast slab of material. Preferably, said at least one projection is formed by a plate-like element which advantageously surmounts the upright member.

The structural frame is preferably assembled from a plurality of modules each of which comprises one of the upright members having a number of said structural members extending from its lower end.

According to a second aspect of the present invention, there is provided a structure comprising a structural frame as defined in any of the last five preceding paragraphs, and a slab of material cast across and incorporating the upper ends of the upright members, there being no substantial structural members other than the slab itself interconnecting the upper ends of the upright members (other than possible reinforcement elements in the slab).

According to a third aspect of the present invention, there is provided a method of erecting a structure, comprising constructing a structural frame composed of a generally planar grid of structural members which meet at nodal points and upright structural members extending upwardly from the nodal points, attaching connectors to points at or adjacent the upper ends of the upright members so that each connector spans the space between an adjacent pair of said members, using the connectors to support shuttering, and casting a slab of material upon the shuttering such that the slab has embedded therein the upper ends of the upright members. The connectors can be removed after casting of the slab, preferably for re-use elsewhere in the structure.

The invention will now be further described, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a perspective view of part of a structural frame according to a first aspect of the present invention; and Figure 2 is a schematic sectional view of part of a structure incorporating the frame shown in Figure 1.

Referring first to Figure 1, the structural frame has a bottom part which is in the form of a generally planar grid and which is composed of a purality of substantially co-planar structural members 10. These members meet at nodal points, with each pair of adjacent points being interconnected by two of the members 10 which are bolted together by means of bolting plates 11 half-way between the nodal points. An upright structural member 12 extends upwardly from each nodal point perpendicularly to the general plane of the members 10, and is provided with attachment eye plates 13 adjacent its upper end, the purpose of which will be described later. Each member 12 is surmounted by a flat plate 14. The structural frame is thus composed of a series of modules, each of which comprises one member 12 having four members 10 radiating in cruciform disposition from its base.

If desired, a stiffening plate 14' (shown in broken line) can be provided around the upright member 12 and secured to the members 10.

In use, the structural frame is used as a space frame for bridging a space between supports (not shown). Referring now also to Figure 2, once the structural frame has been assembled, connector bars 15 are attached to the eye plates 13 such that each connector spans the space between a pair of adjacent members 12. These bars 15 provide a temporary stablisation for the frame and are used to support decking or shuttering 16 upon which a slab 17 of material (e.g.

concrete) is cast, the slab 17 preferably incorporating coventional reinforcement elements. Once the concrete has set, the connector bars 15 can be removed for re-use elsewhere during the construction process. Thereafter, additional storeys can be added above the structure thus produced by repeating the above-described constructional steps, to-create further space frames bridging the aforesaid supports.

In order to facilitate re-use of the connector bars 15, they may be adjustable in length so that variations in the distance between adjacent members 12 can readily be accommodated.

In the finished structure, it will be manifest that the slab 17 extends across and has embedded therein the upper ends of the upright members. 12. No structural members other than the slab 17 itself inter-connect the upper ends of the members 12. The structure is thus a composite one, with some loads being taken by the structural members 10 and 12, whilst other loads are taken by the slab 17.

By utilising such a construction particularly in a multi-storey building, the overall amount of metal employed can be considerably reduced as compared with the structural frame described in the aforementioned UK patent no.

2054694. Moreover, the method of construction is more convenient than that conventionally used to build multi-storey structures since each module can be produced on a jig in a relatively small area and then moved on-site for assembly with other modules. Furthermore, problems associated with conventional fire protection techniques are solved, since it is no longer necessary to spray the joints between the structural members with fireproofing materials on site with the attendant mess. Instead, components e.g. in square or box shapes can be preformed in fireproofing material and simply secured to the structure, or alternatively a spraying technique can still be employed but on each module individually prior to incorporation into the structure at a location where splashing of the fireproofing material can be confined.

In the structural frame described above, the members 10 comprise steel I-section girders, whilst the members 12 comprise steel girders of box section. However, the cross-sectional profile of these components need not be limited to those shapes and can be varied to suit requirements. Furthermore, the members 10 are depicted in Figure 1 as forming a rectangular grid: again, the form of the grid can be altered to suit requirements and may for example include triangular and/or hexagonal arrangements of members 10. Also, the modules depicted in Figure 1 are intended for use within the body of the structural frame.

However, these can be adapted for use along the sides of the frame by omitting one of the members 10 so that the remaining members form a T-shaped array. Equally, the modules can also be adapted for use at corners of the frame by omitting two adjacent ones of the members 10, so that the remaining members form an L shape.

Claims

1. A structural frame comprising a generally planar grid forming a bottom of the frame and composed of a plurality of substantially co-planar structural members which meet at nodal points, and upright structural members extending upwardly from the nodal points, each upright member having at least one attachment point at or adjacent its upper end to which a connector can be attached to support shuttering for casting a slab of material, the connector spanning the space between an adjacent pair of said upright members.

2. A structural frame as claimed in claim 1, wherein each connector is adjustable in length.

3. A structural frame as claimed in claim 1 or 2, wherein the nodal points in each adjacent pair are interconnected by two structural members which are connected together at a location intermediate those points.

4. A structural frame as claimed in claim 3, wherein said structural members are connected together substantially half-way between said nodal points.

5. A structural frame as claimed in any preceding claim, wherein each upright member has keying means at or adjacent its upper end, which is incorporated into the cast slab of material.

6. A structural frame as claimed in claim 5, wherein the keying means comprises at least one lateral projection on the upright member.

7. A structural frame as claimed in claim 6, wherein said at least one projection is formed by a plate-like element.

8. A structural frame as claimed in claim 7, wherein the plate-like element surmounts the upright member.

9. A structural frame as claimed in any preceding claim, assembled from a plurality of modules each of which comprises one of the upright members having a number of said structural members extending from its lower end.

10. A structure comprising a structural frame as claimed in any one of claims 1 to 9, and a slab of material cast across and incorporating the upper ends of the upright members, there being no substantial structural members other than the slab itself interconnecting the upper ends of the upright members.

11. A method of erecting a structure, comprising constructing a structural frame composed of a generally planar grid of structural members which meet at nodal points and upright structural members extending upwardly from the nodal points, attaching connectors to points at or adjacent the upper ends of the upright members so that each connector spans the space between an adjacent pair of said members, using the connectors to support shuttering, and casting a slab of material upon the shuttering such that the slab has embedded therein the upper ends of the upright members.

12. A method as claimed in claim 11, wherein the connectors are removed after casting of the slab.

13. A method as claimed in claim 11 or 12, wherein the structural frame is assembled from a plurality of modules each of which comprises one of the upright members having a number of said structural members extending from its lower end.

14. A structural frame substantially as hereinbefore described with reference to the accompanying drawings.

15. A structure as claimed in claim 10 and substantially as hereinbefore described with reference to the accompanying drawings.

16. A method of erecting a structure, substantially as hereinbefore described with reference to the accompanying drawings.