GB2177435A - Structural frame for buildings - Google Patents

Abstract

The structural frame e.g. consisting of a pitched roof truss 10 supported by vertical stanchions 11 at the ends, comprises principal members e.g. rafters 12 and stanchions, made up of a pair of cold-rolled steel channel sections in back to back spaced parallel relationship linked at intervals by spacing members 13 being like channel sections having their sides attached to the backs of the main member sections and projecting laterally of the latter to mount roof purlins 25 or wall cladding rails 20. <IMAGE>

Description

SPECIFICATION Structural frame for buildings This invention relates to steel structural frames for buildings and particularly to a frame formed from lightweight high duty steel sections with the object of providing ease of transport, handling and erection on site and greater economy in cost of materials and site labour and lifting or other handling equipment for erection.

According to the invention there is provided a structural frame for a building in which at least the main structural members are formed of cold-rolled steel channel sections, at least principal stanchions and principal rafters of the frame being compound members comprising a pair of uniform channel sections disposed in back to back spaced relationship and one or more linking members interconnecting the backs of the pair at longitudinal intervals, each linking member being a cold-rolled steel channel section having parts of opposite sides of the channel attached to said backs for stiffening the compound member and having a portion projecting laterally to serve as mountings for roof purlins or horizontal wall rails of the frame.

The frame may further include bracing or tie members, for example at the eaves and apex of a pitched roof truss, and these are conveniently also cold-rolled steel channel sections attached directly to the pairs of channel sections of the principal members as by bolting them in parallel relationship to the backs thereof.

Heavier duty principal members may be provided by adding a further pair of smaller section channel sections disposed within the main channel sections of the pair so that the compound member comprises four longitudinally extending channel sections.

Preferably holes for bolted attachment of bracing or tie members are pre-punched in the principal member sections at the time of manufacture and are duplicated at selected locations to permit opposite handed assembly, e.g. of the pair of principal rafters making up a pitched roof truss without different left and right hand members having to be provided.

One example of the invention is now more particularly described with reference to the accompanying drawings in which: Figure lisa perspective sketch of framework for a building; Figure 2 is a detailed end elevation of part of said frame and Figure 3 is a plan view on line A-A of Figure 2.

While frameworks for various forms of building may be provided in accordance with the invention the example shown in the drawings is for a single storey pitched roof building, e.g. for industrial use.

Typical roof spans would be seven or twelve metres.

In this example roof trusses 10 (Figure 1) are supported at their ends by principal stanchions 11 which also form the framework of the side walls of the completed building.

Referring to Figure 2 the stanchions 11 and principal rafters 12 of truss 10 are each compound members comprising a pair of cold-rolled steel galvanised channel sections disposed in back to back spaced parallel relationship as best seen in Figure 3 where the two sections 11A, liB making up a stanchion 11 are indicated.

The spacing between the pair of sections accommodates a linking member 13 which is also a coldrolled galvanised steel section of somewhat smaller dimensions than the pair of main sections having its side walls bolted to the backs of the main sections so that it extends laterally of the main sections, one end thereof projecting beyond the latter.

In the case of the linking members 13 used at an intermediate position or positions (depending on the height of the building) along the stanchion members and near the top thereof the projecting portions are directed outwardly and serve for fixing horizontal rails 20 to which sheet metal or other wall cladding 21 of the finished building is attached.

Similarly linking members 13 locating between the pair of members making up the principal rafters 12 project upwardly for the attachment of roof purling 25 to which the roof sheeting 26 of the finished building is attached.

The linking members 13 serve to tie together and stiffen the compound principal members, particularly to resist torsional forces.

Short diagonal stays 30 (Figure 3) may be provided to extend between mounting brackets within the main channel sections 1 1a, 11 b of the stanchions and the rails 20 at some locations for added rigidity.

The bottom ends of the stanchions 11 connect to base plates 31 attached to concrete or other footings or foundations in conventional manner and the tops of the stanchions are connected to the lower ends of rafters 12 by vertical fish plates 32 bolted thereto.

Similar fish plates 33 interconnect the upper ends of the pair of rafters making up the truss.

The roof truss is completed by apex tie members 35 consisting of a pair of cold-rolled channel sections which need not be interconnected for stiffness as they are in tension, each having its back bolted to the back of the associated rafter members.

Eave struts 36 are also provided consisting of a pair of rolled steel channel sections mounted back to back with their sides bolted to the pairs of rafter and stanchion members. These also add to the stiffening of the principal members.

Bolt holes for assembly are readily provided in the members by a punching process at the time of manufacture so that on site drilling is not necessary and, to facilitate assembly, bolt holes are duplicated when necessary so that left and right hand components do not have to be provided, i.e. the components are not "handed" and can be used in assembly of either the left or right hand wing of the truss.

For heavier duty members, e.g. in larger buildings the compound principal stanchions and/or rafters may each be built up from four main longitudinally extending channel sections, for example, for the stanchion, a pair of additional sections of somewhat smaller dimensions than those shown at 1 Ia, 11 b would be nested within the latter with their backs in abutment with the inner faces forming the bottoms of the channel sections.

As the components interfit readily not only is erection speedy and simple but buildings can easily be dismantled for re-location if required.

Claims (11)

1.A structural frame for a building in which at least the main structural members are formed of cold-rolled steel channel sections, at least principal stanchions and principal rafters of the frame being compound members comprising a pair of uniform channel sections disposed in back to back spaced relationship and one or more linking members interconnecting the backs of the pair at longitudinal intervals, each linking member being a cold-rolled steel channel section having parts of opposite sides of the channel attached to said backs for stiffening the compound member and having a portion projecting laterally to serve as a mounting for roof purlins or horizontal wall rails of the frame.

2. frame as in claim 1 including bracing ortie members.

3. Aframe as in claim 2 in the form of a pitched roof truss, having said bracing or tie members at the eaves and apex thereof.

4. A frame as in claim 2 or 3 wherein the bracing or tie members are also cold-rolled steel channel sections attached directly to the backs of the sections forming said principal compound members.

5. A frame as in claim 4 wherein a pair of said bracing or tie member channel sections are attached in parallel relationship to the backs of the principal compound member sections.

6. A frame as in any preceding claim wherein principal members include a further pair of smaller section channel sections disposed within the main channel sections for added strength.

7. A frame as in any preceding claim wherein the principal member sections are formed to include pre-punched holes for bolted attachment of bracing or tie members at predetermined locations.

8. A frame as in claim 7 wherein said holes are duplicated at selected locations on each section to permit opposite handed assembly of identical members.

9. A frame as in any preceding claim in the form of an assembly comprising a pitched roof truss supported at its ends by principal stanchions.

10. A structural frame for a building substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

11. A building including a stuctural frame as in any preceding claim.