Field of the Invention

The invention relates to a composite floor construction and in particular composite floor construction including steel, prefabricated panels, and in some embodiments poured concrete. Background of the Invention

Steel-concrete composite construction is used widely. The construction technique is particularly suited to the construction of wide span floors which are required to support heavy loads, such as multi-story carparks, large open plan office buildings and the like, where the absence of vertical support columns is desirable.

A principal goal of a steel-concrete composite construction is to provide a structure that has better performance than either of the two materials have when functioning separately, with the result that self-weight of a composite construction should be less than the two components’ self-weight, were they to be used independently of one another. Steel-concrete composites can therefore allow the construction of wider span floors and/or taller structures.

One type of steel-concrete composite floor construction known as a down stand beam comprises space apart I-beams with steel trays , often referred to as metal decks, placed laterally across the spaced apart I-beams. Concrete is then poured over the steel trays to form a slab. Various different configurations of steel tray have been developed, each providing certain claimed advantages relative to the steel tray designs.

Another type of steel-concrete composite floor construction known as slim floor construction positions the I-beams at least partially within the depth of the poured concrete. Either steel trays are positioned on the upper surface of the lower flange of the I-beam, with concrete poured over the trays and upper flange of the I-beam, or pre-cast concrete panels are seated on the lower flange of the I-beam. In some examples a reinforcement dowel is positioned such that it passes through the web of the I-beam and sits within the cast concrete.

Another type of steel-concrete composite floor structure comprises spaced apart I-beams with a row of studs along the centre line of the I-beam, each stud extending from the upper surface of the upper flange of the I-beam being provided with studs. Precast concrete slabs are seated on the upper surface of the upper flange of the I-beam adjacent the studs. Each precast concrete panel is provided with slots. The slots of the concrete panels rest on the flange of the I- beam to either side of the row of studs and are aligned with the studs. A reinforcement bar is placed in alignment with the slots and under the head of one of the studs. The small space between the ends concrete slabs is filled with poured concrete, the studs and reinforcement bar sitting within the poured concrete.

One commercially available steel-concrete composite floor construction is described in W02006129057. The floor is described as being shallow and ultra-shallow steel floor systems. I- beams are fabricated with openings therein. The lower flange upon which a timber joist may sit is wider than the upper flange.

There is desire within construction to produce shallower floor cross-sections and floors with wider spans between supporting columns.

Summary of the Invention

According to a first aspect of the invention there is provided a composite floor comprising a plurality of spaced apart beams, at least one prefabricated panel situated between and supported by adjacent spaced apart beams, and a layer of concrete cast in-situ, the layer of concrete overlying the at least one prefabricated panel and at least a part of each of the beams supporting the at least one panel.

According to a second aspect of the invention there is provided a composite floor comprising a plurality of spaced apart beams, at least one prefabricated panel situated between and supported by adjacent spaced apart beams, wherein prefabricated panel has an upper surface a lower surface, side surfaces and end surfaces, the panel comprising two spaced apart elongate side members of a first material and a main panel body of a second material therebetween, the second material being concrete, wherein the upper surface the panel is substantially planar and wherein the lower surface includes at least one rib formed in the second material and extending from one side member to the other, and wherein at least one attachment member is fixed to each of the side members and extends into the main panel body.

Preferably, the spaced apart beams are formed of metal, for example steel. Advantageously, the spaced apart beams are C-channels or I-beams. Each beam may include at least one panel support. At least one panel support may be provided to each side of the beam. Such a beam may support panels situated on each side of the beam.

The panel support may comprise a continuous plate fixed to the beam. The panel support may comprise a single continuous plate attached to the underside of a lower flange of the beam, or a pair of continuous plates, spaced apart laterally from one another and attached to the lower flange of the beam. Alternatively, the at least one panel support may comprise a plurality of separate plates, which may be spaced apart in the longitudinal direction of the beam.

In the case of an I-beam the panel support may be attached to the underside of the lower flange of the beam and may extend outwardly of the edges of said flange, thereby , the panel in use being supported by the panel support.

In another embodiment, the at least one panel support may be provided by a lower flange of the beam. Such a beam may be fabricated such that the lower flange is wider than the upper flange. Typically, such beams are fabricated by cutting components to size and welding the components together.

In one embodiment, reinforcing elements extend through openings in at least one of the plurality of beams, the reinforcing elements being embedded in the layer of concrete.

Preferably, a plurality of reinforcing elements is provided for each beam, each reinforcing element being spaced apart along the longitudinal axis of the beam.

Advantageously, at least one reinforcing element extending through a beam extends beyond a face of at least one prefabricated panel supported by said beam, the face being adjacent the said beam. Preferably, the reinforcing element extends beyond the faces of prefabricated panels supported by said beam to each side of the said beam.

According to a third aspect of the invention there is provided a prefabricated panel having an upper surface, a lower surface, side surfaces and end surfaces, the panel comprising two spaced apart elongate side members of a first material and a main panel body of a second material therebetween, the second material being concrete, wherein the upper surface of the panel is substantially planar and wherein the lower surface includes at least one rib formed in the main panel body and extending from one side member to the other, and wherein at least one attachment member is fixed to each of the side members and extends into the main panel body.

Preferably, at least one attachment member is in the form of a stud, which stud may include a stud shaft and a stud head, the stud head being wider in crop section that the stud shaft.

Advantageously, at least one attachment member is in the form a rod, the rod extending from one side member to the other and being attached to both said side members. The panel may include at least one attachment member is in the form of a stud and at least one attachment member in the form of a rod, the rod extending from one side member to the other and being attached to both said side members.

The panel may include a plurality of attachment members in the form of a studs and a plurality of attachment members in the form of rods, the rods extending from one side member to the other and being attached to both said side members.

In the longitudinal direction of the panel a rod may be situated next to a stud and/or a rod may be situated next to a rod and/or a stud may be situated next to a stud.

Advantageously, the side members are formed of metal, preferably of steel.

The side members may be formed such that the concrete of the main panel body extends into the side members. For example, the side members may comprise C-section channel members. Preferably, the C-section of the channel members is continuous in the longitudinal direction of the side members.

It is preferred that the upper and lower surfaces of the of the side members lie in substantially the same plane as upper and lower surfaces of the main panel body extending between the side members.

The panel may comprise elongate edge regions formed in the main panel body, the at least one rib extending between the edge regions, wherein each elongate edge region abuts a respective one of the elongate side members.

The depth of the panel from the upper surface of the panel to the lower surface, measured at each edge region, may be greater than the depth of the panel from the upper surface of the panel to the lower surface, measured at the at least one rib.

The depth of the panel from the upper surface of the panel to the lower surface, measured at each edge region, may be greater than the depth of the panel from the upper surface of the panel to the lower surface, measured between the at least one rib and the edge regions.

Advantageously, the prefabricated panel includes a plurality of reinforcing members, the reinforcement members being encapsulated by the concrete.

The plurality of reinforcement members may include a plurality of different types of reinforcement members. The different types of reinforcement member may include: an open stirrup; a closed stirrup; reinforcement mesh; and reinforcement bars. In one embodiment, a plurality of closed stirrups spaced apart from one another are arranged within the edge regions of the panel. At least one reinforcement bar may be provided to connect the closed stirrups together. For example, one or more reinforcement bars extending in the longitudinal direction of the panel may be provided, the reinforcement bars attached to the closed stirrups. The reinforcement bars may be situated within the closed stirrups. The reinforcement bars may be attached to a lower part of the closed stirrups may be of a different diameter to the reinforcement bars attached to an upper part of the closed stirrups. For example, the reinforcement bars attached to the lower part of the closed stirrups may be 18mm in diameter, whereas the reinforcement bars attached to the upper part of the closed stirrups may be 8mm in diameter. The number of reinforcement bars attached to the upper and lower parts of the closed stirrups may be the same or different. For example, three reinforcement bars may be attached to the lower part of the closed stirrups, whereas two reinforcement bars may be attached to the upper part of the closed stirrups.

Advantageously, the panel includes a plurality of open stirrups spaced apart from one another. It is preferred that a part of each open stirrup is arranged within the at least one rib of the panel. At least one reinforcement bar extending in the longitudinal direction of the at least one rib may be provided, the at least one reinforcement bar attached to the open stirrups, preferably in the lower part of the open stirrups. Advantageously, the at least one reinforcement bar extending through the open stirrups extends over or under the at least one reinforcement bar extending through the closed stirrups, and preferably the said reinforcement bars are attached together.

Reinforcement bars may be attached to other reinforcement components, such as stirrups or mesh with mechanical fixings, such as wire ties or other suitable fasteners, or by welding.

Preferably, the upper part of the closed stirrups and the upper parts of the open stirrup lie in substantially the same plane.

A reinforcement mesh may lie over and sit on the upper parts of the closed and open stirrups and may be attached thereto.

According to a fourth aspect of the invention there is provided a method of constructing a floor comprising the steps of: a) providing a plurality of beams; b) providing at least one prefabricated panel; c) positioning individual beams in a spaced apart relationship to one another; d) positioning the at least one prefabricated panel such that said at least one panel is supported by adjacent spaced apart beams.

The method of construction may include the further steps of: e) inserting at least one reinforcing element through at least one of the spaced apart beams such that the at least one reinforcing element extends over and is situated above the at least one panel; e) pouring concrete over said at least one prefabricated panel, the beams supporting the said at least one prefabricated panel and reinforcing elements; f) allowing the poured concrete to cure.

Step (b) may include positioning a plurality of prefabricated panels such that each panel is supported by the adjacent spaced apart beams and such that adjacent prefabricated panels abut one another.

The prefabricated panel may be a prefabricated panel according to the second aspect of the invention.

Preferably, the reinforcing elements are positioned such that each reinforcing element extends over and is situated above the at least one panel situated to each side of the beam through which the reinforcing element extends. It is preferred that the ends of at least one reinforcing element distal from the beam through which the reinforcing element extends are spaced apart from the adjacent beam.

Brief Summary of the Drawings

In the Drawings, which illustrate preferred embodiments a composite floor according to the invention, and which are by way of example:

Figure 1 is schematic representation of components of a composite floor of the invention;

Figure 2 is a cross-section of the composite floor of the invention;

Figure 3 is a schematic representation of a first type of prefabricated panel of the composite floor;

Figure 4a is a schematic representation of a second type of prefabricated panel of the composite floor; Figure 4b is a cross-section on axis A-A of the prefabricated panel illustrated in Figure 4a; Figure 4c is a cross-section on axis B-B of the prefabricated panel illustrated in Figure 4a; Figure 5a is a schematic plan view of the prefabricated panel illustrated in Figure 3;

Figure 5b is an end view of the prefabricated panel illustrated in Figures 3 and 5a;

Figure 6a is a schematic plan view of the prefabricated panel illustrated in Figure 4;

Figure 6b is an end view of the prefabricated panel illustrated in Figures 4 and 6a;

Figure 7 is an end view of the prefabricated panel illustrated in Figures 4a to 4c;

Figure 8 is a schematic representation of a part of the prefabricated panel illustrated in Figure 7;

Figure 9 is a schematic representation of a part of the prefabricated panel illustrated in Figure 7 and 8.

Detailed Description of the Preferred Embodiments

Figures 1 and 2 illustrate a composite floor 1 , the floor 1 comprising spaced apart beams 2 and prefabricated concrete panels 3 extending between the spaced apart beams 2. In the illustrated example, each beam 2 is an I-beam, formed of metal and comprising spaced apart flanges 2a, 2b joined by a web 2c. The lower flange 2b has a support plate 2d attached thereto. The support plate 2d provides a flat surface 2d’ upon which the panels 3 rest. An alternative approach is to fabricate an asymmetric flange in which the bottom flange 2b is wider than the top flange 2a, the concrete panels being supported on the bottom flange.

In the illustrated example, the support plate 2d is welded to the bottom flange 2b and extends the length of the beam 2. Alternatively, the support plate 2d could be replaced with a series of spaced apart support plates, or two continuous plates, separate from one another, could be provided, a respective one attached to each side of the bottom flange 2b.

As can be seen from Figure 2 in particular, the upper surface 3’ of the concrete panels 3 sits below the upper surface of the flange 2a of beam 2. The composite floor 1 includes reinforcement members which are inserted through holes 2e in beam 2. The reinforcement members are metal (typically steel) rods 4. As can be seen from Figure 2, the rods 4 extend over the panels 3 but are spaced above the upper surface 3’ of said panels 3. The space between the upper surface 3’ of the panels 3 and the space between the end faces 3” of the panels and the beam 2 is filled with concrete 5 to the level of the upper surface of flange 2a.

The composite floor 1 may be formed simply by placing the prefabricated panels 3 onto the support plate 2d. They may be held securely in position by their self-weight and by virtue of butting up against each other, without the need for further fasteners or a concrete screed. In such a case, the dimension of the beam 2 will be selected such that the upper surface of the flange 2a sits substantially flush with the upper surface of the prefabricated panel 3, and in general the dimensions of the flange will be selected such that any expansion of contraction of the flange due to changes in environmental conditions does not reduce the width of the bearing surface below a pre-defined minimum, which will depend on the application, but may for example be in the region of 50mm.

Figures 3 to 6a illustrate the panels 3 in greater detail. Each panel 3 comprises spaced apart channel members 3a, each channel member 3a having a plurality of spaced apart studs 3b extending from the channel to which they are attached (for example, by welding) towards the channel member 3a on the opposing side of the panel 3.

Each panel 3 includes a part that is cast from concrete. The concrete fills the space provided by the channel members 3a and extends between the spaced apart channel members. A former is used during the casting process. The shape of the former is such that the panel 3 has edges 3e which fill the channel members 3a and extend inwardly of the channel members 3a, which edges are deeper than the major part of the panel 3. The shape of the concrete former also results in the panel 3 comprising spaced apart ribs 3f which extend across the panel 3.

In order to strengthen the panel 3 various forms of reinforcement are used. The ribs 3f are reinforced by metal II shaped open stirrups 3g. The open stirrups 3g are tied to a metal reinforcement mesh 3h.

In the embodiment illustrated in Figure 4a reinforcing dowels 3c extend between and are attached to the channels 3a. Typically, the dowels are welded to the channels 3a. The embodiment illustrated in Figure 3 does not utilise the reinforcing dowel.

Figures 5a and 5b illustrate the channels 3a of Figure 3. The skilled person will understand that as concrete is poured the space within the channels 3a will be filled, encasing the shear studs 3b. The stud heads 3b’ are of greater diameter than the stud shafts 3b” providing for any force pulling the channels 3a apart to be resisted. The spacing between adjacent shear studs is designed according to the requirements of the particular composited floor.

Figures 6 and 6b illustrate the channels of the embodiment illustrated in Figure 4a to 4c. As can be seen, shear dowels 3c extend between the channels 3a. A shear stud 3b is situated between adjacent shear dowels 3c. The ratio of shear studs to shear dowels and the spacing therebetween is designed according to the requirements of the particular composited floor.

In order to construct a composite floor according to the invention spaced apart beams are positioned. Panels 3 are then placed such that they extend between adjacent spaced apart beams 2 and rest of a beam support flange 2d of the beam 2. Adjacent panels 3 between two spaced apart beams 2 about each other edge to edge.

The next step involves inserting reinforcement dowels 4 through openings 2e in the web 2c of the I-beam 2.

Finally, concrete 5 is poured to fill the space shown in cross-hatched lines in Figure 2. In this embodiment, the upper surface of concrete 5 lies in substantially the same plane as the upper surface of the upper flange 2a of the beam 2. The upper surface of the concrete 5 may lie in a plane above the upper surface of the upper flange 2a of beam 2.

The number, dimensions and material of the reinforcing dowels 4 will depend on the design parameters of a particular composite floor. However, what is important where at least one reinforcing dowels extending through the web is used is that the rod extends over at least one of the panels 3. In Figure 2 the reinforcing dowel extends above the panels 3 located on both sides of beam 2. However, in another embodiment, alternated reinforcing dowels may extend of one or other of the panels 3 supported by beam 2.

Figures 7 to 9 illustrate the reinforcement of the panel 3. Each panel 3 has a series of spaced apart sets of open stirrups 3g. Within each set of stirrups, adjacent open stirrups 3g are spaced apart from one another across the width of the panel and are attached to each other by bars 3i, which lie parallel with one another and against the respective bottom corners of the open stirrups 3g. The bars 3i may be tied to the stirrups with wires, other suitable ties or mechanical fixings or by welding.

Figures 7 and 8 illustrate closed stirrups 3j, which extend along each long side of the panel

3 within the edges 3e thereof. As can be seen from Figure 8, the closed stirrups 3j are spaced apart along the length of the panel and are tied to bottom bars 3k, by wires, other suitable ties or mechanical fixings, or by welding.

The closed stirrups 3j are also fastened by top anchor bars 3I. These top anchor bars are attached to the closed stirrups using one of the methods described with reference the bottom bars 3 k.

The reinforcement mesh 3h extends over and are attached, using one of the methods described above, to the closed stirrups 3j and top anchor bars 3I, and the bars 3i extend over the bottom bars 3k and are attached thereto, again, using one of the methods described above. In this way, all the reinforcement members are tie together.

The reinforcement members are typically formed of metal, such steel.

Figure 7 also illustrates the shear studs 3b and reinforcing dowels 3c, both of which are fastened to the channel members 3a.

It has been found that by fabricating the panels 3 in the manner described above, they can be formed to much tighter tolerances than is possible with ordinarily cast concrete, whether such concrete is cast on or off site. The metal members extending along the long sides of the panels are of particular importance in facilitating the manufacture of the panels 3 to tight tolerances.

In floor construction methods of the prior art additional steps following the placement of concrete panels is necessary to finish the floor. For example, grouting may be placed where adjacent panels butt up against one another, or, a full screed may be applied over the panels. The panels of the invention can be placed between beams with no additional steps needed to form the floor. The space between adjacent panels is so small that there is no need to grout the joint. Further, the metal of the side members of the panel protects the edge of the panel against damage, whereas unprotected concrete may chip and then fracture from an unprotected edge. The panels may be fastened to a supporting beam, or they may be held in place simply by their self-weight and abutment with adjacent panels, or other components of the floor structure. Alternatively, a screed and reinforcement bars may be utilised as described herein.