Deck structure

Abstract

A modular structure for suspended floors or roofs which includes a pair of beams 4 supporting a floor slab 5a/5b which is preferably manufactured at ground level and then lifted into position as a modular unit 1. The beams 4 are preferably made of steel and the floor 5a/5b is preferably made of concrete, which may be precast units or may be concrete poured onto profiled steel decking. In either case, the beams 4 and slab 5a/5b are structurally designed to act compositely.

Description

This invention relates to a modular deck structure for suspended floors and/or roofs, preferably floors and/or roof which include a pair of beams supporting a deck, which deck is preferably manufactured at ground level and then lifted into position as a modular unit.

This invention can be applied to any flat, pitched or curved roof, or to a suspended floor above, at, or below ground level.

Buildings, and in particular new multi-storey buildings, usually have relatively large areas which have regular layouts of floor beams and columns, but these are generally constructed as individual elements comprising of (steel or concrete) support beams and columns onto which is laid a concrete slab, which is usually poured on site (“in situ”) onto profiled steel decking, or may be delivered to site as individual pre-cast slab elements.

Similarly for lightweight roofs, there are usually relatively large areas which have regular layouts of roof support beams (“rafters”) and secondary members (“purlins”), but these are generally constructed as individual elements onto which is fixed on-site a weatherproof covering and/or insulation.

Concrete roofs are usually of similar construction to concrete floors, and therefore reference to concrete floors will be taken as including concrete roofs.

Normal construction practice involves erecting a framework structure consisting of a grid of beams and columns (or walls). At this stage there are very large voids between the grids of beams. These voids create a potential for accidents by any person who needs to carry out any work on these beams (which includes work involved in actually placing the precast concrete slabs or actually fixing the decking etc.). Again, roof construction normally follows a similar sequence and involves personnel working adjacent to large open areas. Therefore there is a potential safety issue in preventing injury to anybody falling from these beams, until such time as either the pre-cast concrete units have been installed, or the decking (for insitu concrete) or roof covering has been fixed, thereby closing off the voids.

It is common knowledge that work on construction sites, and in particular working at heights over 2 m above ground, known as “working at height”, is a major source of accidents and therefore any reduction in this area of work should reduce the potential for accidents land injury to construction personnel.

Steelwork and concrete composite action is utilised widely throughout the construction industry; however this is normally the result of casting concrete floors on site (“insitu”) on top of a steelwork support frame. Also, unless the steel beams are adequately temporarily supported (“propped”) during the construction stage, then the composite strength of the beam and slab would only be fully applicable to resisting the loads that are applied after the concrete had gained it's full design strength. It is not usual to prop the steel beams during the construction of such composite sections because the props would have to remain in place until the concrete had sufficient strength to act compositely with the steel beams. This could be 14 to 28 days, and during this time the props would interfere with any other work below. Furthermore, with second and subsequent floor levels, such temporary props would have to be supported from the floor (below) that has only just been laid.

Large span precast concrete systems are available which utilise off-site manufacture of the concrete element; however these products tend to be heavy and require more work to be undertaken on site to install. Due to different manufacturing tolerances on precast concrete, the pre-manufactured components need to adopt joint systems which provide for more adjustment once the unit is installed on site.

The overall depth of the floor system has a cost effect on a building. The floor to ceiling height of any particular building is usually set by various factors, some of which may be statutory requirements and others which may be perceived comfort factors (e.g. a large open area with a low ceiling height may be perceived as claustrophobic). The overall floor to floor height (“storey height”) is then a summation of the floor to ceiling height plus the “floor zone”, which comprises of the floor depth plus any void depth required for the passage of services etc. Ideally, this floor zone should be as small as possible so that the overall storey height can be as small as possible which then reduces the overall height of the total building and hence reduces the cost of the building. This reduction of storey height becomes more of a factor the greater the number of floors.

Lightweight roof construction usually consists of main rafters in the order of 4.0 m to 8.0 m centres, which in turn support (usually) light gauge steel purlins in the order of 1.5 m to 2.5 m centres. The roof covering is then laid onto these purlins and fixed down using some form of screwed fixing. During all these operations, personnel are working in a potentially unsafe environment. Safety netting should reduce the consequences of any fall and edge protection should help guard against any fall, but these have a cost and time (fixing/dismantling) associated with them. Also, there is quite a long timescale between starting to erect the rafters and actually producing a weatherproof surface because all the individual elements are fixed together in a particular sequence which cannot start until the preceding item has been fixed.

The objectives of this invention are to provide a floor and/or roof system which reduces insitu working, thereby saving time on site, reducing the risk of accidents from working at height, which has a relatively small overall depth and which is cost effective.

According to a first aspect of the present invention, a modular deck section for a building comprises a bed section and at least one support section, which at least one support section is operable to support the bed section.

Preferably, the modular deck section incorporates at least two support sections, located at or close to opposite edges of the bed section.

The support sections are preferably located on a lower face of the bed section. The support sections are preferably inward of outer edges of the bed section, to leave an overhang along each of said opposite edges.

The modular deck sections can be a floor section or a roof section.

Preferably, the support sections are beams, which are preferably substantially straight along an edge of the bed section. The support sections may be curved with the bed section.

The bed section may be made of a base portion, preferably of metal and a body portion, preferably of concrete.

Preferably, the bed section and support sections act compositely to support their own weight and/or an applied load. Preferably, the composite action is achieved by allowing setting of the bed section before loading of the modular deck section, preferably before construction.

Preferably, the modular deck section is adapted to be secured to at least one other modular deck section to form a deck assembly.

The deck section may also/alternatively be a wall section. The invention extends to a deck assembly comprising a plurality of modular deck sections according to the first aspect.

According to a second aspect of the present invention a method of construction comprises forming a plurality of modular deck sections comprising a bed section and at least one support section securing the modular deck sections together to form a deck assembly, said modular deck sections being secured to support beams; and securing said support beams to support columns.

Preferably, the modular deck sections are formed off-site, prior to transportation to a construction site.

The modular deck sections may be partially formed off-site to include the support sections and a base portion of the bed section. In which case a concrete section may be applied to the base portion after erection of a structure formed by the modular deck sections, support beams and support columns.

The support sections of the deck sections are preferably located inwards of edges of the bed section, allowing a cantilever effect for the structure, when the deck sections are supported by the support sections.

Preferably, support beams are arranged in pairs, one either side of their respective support columns. One support beam of said pair preferably has an end of at least one deck section secured thereto, whilst the other of said pair of support beams preferably has at least an end of at least one other deck section secured thereto. The support beams are thereby advantageously continuous passed their support columns.

According to a third aspect of the invention a method of forming a modular deck section comprises:

• • forming at least one support section and a base portion of the bed section into a base deck section.

The base deck section preferably comprises at least two support sections.

The method preferably includes supporting the support sections and optionally the base section whilst forming a body portion of the bed section, which body portion is preferably concrete. The method preferably includes continuing supporting the support sections/base section until the body portion has set.

The support sections may be supported to gi e a camber to the support sections, preferably by elastic deformation thereof. Said deformation may be retained after application of the body section.

The invention extends to a method of calculating values of the size, spacing and or other features of the deck sections and/or elements thereof. The invention further extends to a computer program operable to perform said method of calculating and a recordable medium bearing that computer program.

All of the features described herein may be combined with any of the above aspects, in any combination.

This invention provides a modular structure which is best (although not exclusively) suited to a regular layout of supporting columns or walls, and which is composed of the following basic components:—

• • a) Deck modules manufactured preferably at ground level, comprising of pairs of beams supporting a floor or roof deck. The beams are preferably made of steel. The deck could be either (i) Heavy Duty, or (ii) Lightweight.
    • i) For heavy duty, the deck is preferably made of concrete, which may be precast units or may be concrete poured onto profiled steel decking or preformed shuttering. In either case, the beams and concrete deck are structurally designed to act compositely.
    • ii) For lightweight, the type of decking could be preferably profiled sheeting, steel plate or timber products or la combination of these materials, with or without a separate waterproofing layer (such as tiles, felt etc.). The roof covering is supported by small, lightweight purlins running perpendicular to and supported by the main deck beams (rafters).
  • The deck beams may have holes through the web to facilitate the passage of service ducting.
  • b) “Transfer beams” running perpendicular to and supporting the deck modules. These transfer beams are preferably provided in pairs where the deck-pans are placed end-to-end, and may also be deck modules themselves.
  • c) Columns or walls to support the transfer beams.

The beams are preferably made of steel. The deck could be either (i) Heavy Duty, or (ii) Lightweight.

For heavy duty, the deck is preferably made of concrete, which may be precast units or may be concrete poured onto profiled steel decking. In either case, the beams and concrete deck are structurally designed to act compositely.

For lightweight, the type of decking could be preferably profiled sheeting or steel plate or timber products or a combination of these materials.

A finishing surface (e.g. waterproofing layer for roofs) may be included as required.

The use of a pre-manufactured deck system allows a large amount of the work required in constructing a floor or roof to be undertaken at ground level and off-site. This produces the following benefits:—

• • a) There will be a reduction in the amount of site work, and particularly “working at height”. Any reduction in this area of work should reduce the potential for accidents and injury to construction personnel.
  • b) The overall time on site will be reduced, leading to a reduction in the amount of disruption to any other activity on the site and/or to an earlier completion time, hence an earlier use of the weatherproof or completed building.
  • c) The deck beams for concrete decks can be continuously supported during manufacture, therefore the full composite interaction properties of the concrete deck and the steel beams is available to resist the total load. In the usual method of in-situ cast composite beams the selfweight of the concrete deck (approximately half to a third of the total load on a typical office building) has to be resisted by the steel beam alone (because the concrete has no strength when it is first poured), therefore e continuous support during manufacture provides a stronger solution. The calculations normally used to calculate strength requirements can be modified by removing factors relating to the wet concrete, because of the continuous support provided during manufacture.
  • d) The deck beams for concrete decks can easily be pre-cambered during manufacture, by varying the relative levels of the temporary supports during manufacture; this does not entail “plastic” deformation of the beam as would be the usual case when pre-cambering a steel beam for in situ construction. Pre-cambering allows the amount of deflection to be controlled and reduces the amount of shrinkage cracking of the concrete slab. For off-site manufacture, it is possible to utilise the selfweight of the wet concrete to create the pre-camber, rather than the need to create the pre-camber by force.
  • e) Greater dimensional accuracy of the manufacture of the component parts can be achieved off-site. This allows composite modules of steel and concrete to be delivered to site with the accuracy currently only achieved with structural steel.

There may be circumstances where a particular construction site may not be able to provide access to a crane large enough to lift the complete concrete deck modules. In this case, the concrete would need to be poured insitu, thereby reducing the benefits of the complete system. However, there would still be the benefit that the module would contain the profiled metal deck, which would immediately provide a safe working platform without requiring “working at height”.

This invention also provides a method of manufacturing the modular components of the deck modules.

This invention also provides a method of constructing the modular structure.

The invention also provides for new analysis techniques to be applied which are not applicable to traditional forms of construction.

The deck module system for concrete floors and roofs maintains lower overall floor/roof depth due to the use of composite action whilst bringing the advantage of offsite manufacture of the components.

The deck module system for lightweight floors and roofs provides a system whereby the use of complete modules of floor/roof covering enables a larger area to be weatherproof earlier than traditional methods, whilst bringing the advantage of offsite manufacture of the components.

A preferred embodiment of this invention will be described below by way of example, with particular reference to the accompanying drawings, in which:—

FIG. 1 shows a perspective view of part of a heavy duty floor structure together with part of a lightweight roof structure in a building, in this drawing, the roof structure is curved with a valley condition;

FIG. 2 shows a cross section through a typical deck-pan module based on a pre-cast concrete slab system;

FIG. 3 shows a cross section through a typical deck-pan module based on a concrete slab on profiled metal decking system;

FIG. 4 shows a perspective view of part of a floor structure in a building, with a cut-away area showing beams and shear studs based on a pre-cast concrete slab system;

FIG. 5 shows a perspective view of part of a floor structure in a building, with a cut-away area showing beams and shear studs based on a concrete slab on profiled metal decking system;

FIG. 6 shows a schematic arrangement for supporting the deck-pan modules and providing a pre-camber, during fabrication;

FIG. 7 shows part of a section along typical end-to-end deck-pan modules at a junction between deck pan beams and a pair of transfer beams;

FIG. 8 shows a cross section through a typical deck-pan module at an end condition;

FIG. 9 shows part of a section along a typical deck-pan module at a junction between a pair of transfer beams and a column;

FIG. 10 shows a perspective view of part of a lightweight roof structure in a building, with a cut-away area showing rafters and purlins;

FIG. 11 shows part of a section along typical end-to-end lightweight roof modules at a valley junction between pairs of deck-pan module beams and a single transfer beam; and

FIG. 12 shows a cross section through a pair of typical lightweight roof modules.

A schematic example of a floor and roof structure of the invention is shown in FIG. 1.

The floor and roof areas are produced by combining a number of modular deck-pan units 1 side by side, and further by combining a number of modular deck-pan units 1 end to end. The deck-pan module length and width can be varied to suit the building and column layout, within the limits of transportation dimensions and weight limitations, which typically limit a width to 3.5 m for practical purposes. Each end of each deck-pan is supported by a transfer beam 2. Where deck-pans are provided end to end, then there may be two transfer beams 2, which may also be provided as deck-pans 1a (rather than individual beams). The transfer beams 2 are supported by columns 3.

The roof is shown with a curved profile for this example, with only a single line of transfer beams 2 in the valley, although again, two beams 2 may be more appropriate in certain situations.

FIGS. 2 and 3 show variations of sections through the deck-pan system for different types of concrete slab. FIG. 2 shows a pre-cast concrete slab and FIG. 3 shows an “insitu” concrete slab on profiled metal decking (insitu in this case can be either poured off site or, if necessary, on site).

As shown in FIGS. 2 and 3, the heavy duty deck-pan modules 1 consist of a pair of beams which are preferably made of steel, which are spaced inboard of the module width so that they satisfy the structural design edge distance requirements for composite interaction with the concrete deck 5a or 5b to give a cantilever effect. This allows a gap between the flanges of the beams for access to bolts between the beams 4, and also reduces the span of the concrete deck itself, thereby introducing further economy by enabling the slab thickness to be reduced.

The interaction between the steel beam 4 and the concrete deck 5a/b is achieved by using shear studs 6, although other methods of providing the shear interaction are available, such as brackets welded to the steel parts.

For the pre-cast concrete slab 5a shown in FIG. 2, the shear studs 6 are welded to the steel beams 4 and the concrete slabs 5a are cast with holes 10 at the same spacing as that of the shear studs 6. The concrete slabs 5a are supported on the steel beams 4 with the shear studs 6 protruding into the holes 10 in the slab. The holes in the slab Sa, together with a gap-joint 9 between each concrete slab 5a are then filled with a suitable filler, preferably an epoxy (for rapid, high strength) bonding agent.

For the metal deck solution 5b shown in FIG. 3, the shear studs 6 are welded to the steel beams 4 through metal decking 7. Light gauge metal edge trim 8 is fixed to the metal decking 7 around the perimeter of the deck-pan module 1 to contain the wet concrete 5b which is poured onto the metal deck 7 to the required thickness. The deck-pan units 1 can be bolted together through the edge trim 8 to provide a shear interaction between each unit, thereby creating a continuous diaphragm.

FIG. 4 shows an isometric view of part of the floor, with a cut-away showing the various parts using the pre-cast concrete slab system.

FIG. 5 shows an isometric view of part of the floor, with a cut-away showing the various parts using the concrete slab on profiled metal decking system.

During the above noted manufacture of the heavy duty deck-pan units (either pre-cast or metal deck solutions), the steel beams are suitably supported with supports 15 off the ground (see FIG. 6), in a manner so as to produce the necessary pre-camber and to provide the necessary regularity of support to the steel beams 4 to resist the weight of the concrete slab 5a (without undue stresses and strains in the steel beam alone) until such time that the slab 5a and/or epoxy bonding agent 9 has gained sufficient strength to enable adequate strength interaction with the steel beams 4.

FIGS. 7 and 8 show sections through the end of the deck-pan module 1, being supported by a transfer beam 2.

FIG. 7 shows part of a section along typical end-to-end deck-pan modules 1 at the junction between the deck pan beams 4 and a pair of transfer beams 2 (which is also a deck-pan beam la in this case). This is shown based on a pre-cast concrete slab 5a system, but could also be incorporated with a concrete slab 5b on profiled metal decking system or the lightweight system.

FIG. 8 also shows a section through the end of a deck-pan module 1, which would correspond to, for example, an external edge of the floor. This is shown based on a pre-cast concrete slab 5a system, but could also be incorporated with a concrete slab 5b on profiled metal decking system or the lightweight system. It would be unusual for the depth of the transfer beam 2 to be a restriction at the edge of a building, and the column spacing may be smaller than for internal columns, therefore this transfer beam 2 may be a single, non-composite beam. However, if necessary for any particular circumstance of building layout, then this could also be a pair of beams with its own composite slab (i.e. a deck-pan transfer beam 1a).

In either case, a fabricated bracket 12 welded to the transfer beam 2 preferably has a seating cleat 11 which allows the deck-pan beam to sit down onto this seating cleat 11, thereby making erection easier and safer (than would be the case with just a side fixed connection). The exact detail of these cleats 11 will vary depending upon the relative depths of each of the beams 2.

The endplate of the deck-pan beam is then finally bolted to the end of the fabricated bracket 12 supplied with the transfer beam 2. The aforementioned cleats 11 are intended only to assist with erection of the modules 1, and can either be left in place, or removed (after the endplates 12 are bolted together) for further re-use, although this will also depend on the exact detail of these seating cleats 11, which in turn will depend on the relative beam 2 depths.

FIG. 9 shows part of a section along a typical deck-pan module 1 at the junction between the transfer beam 2 (which is also a deck-pan beam la in this case) and a column 3. This is shown based on a pre-cast concrete slab 5a system, but could also be incorporated with a concrete slab 5b on profiled metal decking system or the lightweight system. Again, the column 3 preferably has a seating cleat 14 which allows the transfer beam 2 to sit down onto this seating cleat 14, thereby making erection easier and safer (than would be the case with just a side fixed connection). The transfer beam 2 is supplied with a fabricated bracket 13 which is then finally bolted to the face of the column 3. The aforementioned cleats are intended only to assist with erection of the modules 1, and can either be left in place, or removed (after the endplates 13 are bolted together) for further re-use, although this will also depend on the exact detail of these seating cleats 14, which in turn will depend on the relative beam depths.

FIGS. 7 and 9 show that the column 3 is received between the pairs of beams 2, which allows for continuity of the beams 2, with consequential structural advantages.

FIG. 10 shows part of the lightweight system used in this example for a curved roof. The deck beams 4 support lightweight purlins 15 which in turn support the decking sections 1. For the roof structure, the decking 1 would fall towards a gutter 17 for drainage purposes.

FIG. 11 shows part of a longitudinal section along a roof deck. In this example the deck beams 4 are only supported by a single transfer beam 2 in the valley (end-to-end condition) and the deck beams 4 also sit directly onto the top flange of the transfer beam 2 rather than having a side bracket connection as shown for the heavy duty modules (FIGS. 7 and 8). If headroom was critical at this point, or maybe for other situations, this valley detail could be similar to those shown in FIGS. 7 and 8, with either a single or double transfer beam 2. To create the curved effect the purlins 15 can be supported by varying heights of brackets 16.

FIG. 12 shows a cross section through a lightweight deck 1, using a profiled steel roofing sheet 5c for this example. The roof sheets 5c overlap at the sides to create a weatherproof surface between one module 1 and the next.

The floor or roof structure according to this invention allows for various layouts to suit the size, shape and spacing arrangement of supporting column 3 in the required building, which is economical to produce and which can be manufactured off-site for increased safety.

The embodiments provide an advantage in that the floor zone height may be reduced by 120 mm compared to a typical construction.

The deck sections may be wall sections having the same advantages as referred to above.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A modular deck section for a building comprises a bed section and at least one support section, which at least one support section support is operable to the bed section.

2. A modular deck section as claimed in claim 1,which incorporates at least two support sections, located at or close to opposite edges of the bed section.

3. A deck section as claimed in claim 1, in which the support sections are located on a lower face of the bed section.

4. A deck section as claimed in claim 1, in which the support sections are inward of outer edges of the bed section, to leave an overhang along each of said outer edges.

5. A deck section as claimed in claim 1, in which the support sections are beams, which are substantially straight along an edge of the bed section.

6. A deck section as claimed in claim 1, in which the bed section and support sections act compositely to support their own weight and/or an applied load.

7. A deck section as claimed in claim 6, in which the composite action is achieved by allowing setting of the bed section before loading of the modular deck section.

8. A deck section as claimed in claim 1, which is adapted to be secured to at least one other modular deck section to form a deck assembly.

9. A deck section as claimed in claim 1, which is also/alternatively a wall section.

10. A deck assembly comprising a plurality of modular deck sections as claimed in claims 1.

11. A method of construction comprises forming a plurality of modular deck sections each comprising a bed section and at least one support section; securing the modular deck sections together to form a deck assembly, said modular deck sections being secured to support beams; and securing said support beams to support columns.

12. A method as claimed in claim 11, in which the modular deck sections are formed off-site, prior to transportation to a construction site.

13. A method as claimed in claim 11, in which the modular deck sections are partially formed off-site to include the support sections and a base portion of the bed section.

14. A method as claimed in claim 13, in which a concrete section is applied to the base portion after erection of a structure formed by the modular deck sections, support beams and support columns.

15. A method as claimed in claim 11, in which the support sections of the deck sections are located inwards of edges of the bed section, allowing a cantilever effect for the structure, when the deck sections are supported by the support sections.

16. A method as claimed in claim 14, in which the support beams are arranged in pairs, one either side of their respective support columns.

17. A method as claimed in claim 16, in which one support beam of said pair has an end of at least one deck section secured thereto.

18. A method as claimed in claim 17, in which another of said pair of support beams has at least an end of at least one other deck section secured thereto.

19. A method of forming a modular deck section comprises:

forming at least one support section and a base portion of the bed section into a base deck section.

20. A method as claimed in claim 19, in which the base deck section comprises at least two support sections.

21. A method as claimed in claim 19, which includes supporting the support sections and optionally the base section whilst forming a body portion of the bed section.

22. A method as claimed in claim 19, in which the support sections are supported to give a camber to the support sections, by elastic deformation of the support sections.

23. A method of calculating values of the size, spacing and/or other features of the deck sections formed according to the method claim 19 and/or elements thereof.

24. A computer program is operable to perform the method of claim 23.

25. A recordable medium bearing a computer program according to claim 24.