GB2167098A - Floor of settable material - Google Patents

Abstract

A method of constructing a floor comprises the steps of arranging a plurality of joists 10 in parallel but spaced-apart relationship, each joist having a pair of projections 11, one at each side, arranging shuttering 12 between the joists, supported by the projections, pouring a settable composition 14 onto the shuttering, to occupy the space between the joists, and allowing or causing the composition to set to provide infill members between the joists, the shuttering being such that the infill members have a depth which increases adjacent to the joists which are stronger than conventional rectangular infill blocks. <IMAGE>

Description

SPECIFICATION Floors and method of construction floors The invention relates to floors and to methods of constructing floors. In particular the invention is concerned with a relatively modern method of constructing floors, in which a plurality of joists, for example of reinforced or prestressed concrete, are arranged in parallel but spaced-apart relationship, each joist having a pair of projections, for example flanges, one at each side, and a plurality of conventional infill blocks, for example walling blocks of concrete or breezeblock, are then laid between each pair of parallel joists, resting on the flanges of the joists.

The invention seeks to provide a method which is cheaper than the known method, by effectively forming the infill blocks in situ.

Accordingly the invention provides a method of constructing a floor, comprising the steps of arranging a plurality of joists in parallel but spacedapart relationship, each joist having a pair of projections, one at each side, arranging shuttering between the joists, supported by the projections, pouring a settable composition on to the shuttering, to occupy the space between the joists, and allowing or causing the composition to set to provide infill members between the joists, the shuttering being such that the infill members have a depth which increases adjacent to the joists.

We have discovered that this can lead to infill members being formed which are stronger than conventional rectangular infill blocks.

Preferably the shuttering has an upper surface which is curved upwardly so that the infull blocks take the form of an arch.

The shuttering may be made from any material which has sufficient strength and/or rigidity to withstand the load of the composition as it is poured on to the shuttering, for example cardboard or other sheeting material, polystyrene or other plastics material, timber or timber substitute.

Preferably the shuttering comprises flexible sheet material, for example cardboard, which is bent under stress to provide the desired shape and is then restrained in the bent position, for example by the joists. We have found that this considerably increases the capacity of thin material to carry the relatively heavy load of settable material such as a load of wet concrete.

Preferably retaining means are provided to maintain the joists in position, against the sideways load applied by the unset material, at least until the material has set.

The retaining means may comprise tie rods.

Each end of each tie rod may extend downwardly so that one end of each rod can hook over one joist and the other end of the tie rod can hook over an adjacent joist.

It is not essential for the shuttering to contribute to the load bearing capacity of the finished floor.

On the other hand, the invention includes the use of shuttering which would contribute to the load bearing capacity of the finished floor, for example shuttering which itself consists of thin, appropriately shaped, polystyrene or concrete blocks.

It is not essential that the method according to the invention be used to construct an entire floor.

For example the method according to the invention may be used only in selected areas, for example at the edge of a floor where blocks of conventional dimensions would not fit without being specially cut, the remainder of the floor being constructed by a conventional method.

Additionally upwardly extending shuttering may be used to prevent the composition from flowing in the direction of the longitudinal axis of the joists before the composition has set.

The additional shuttering may have a profile arranged to fill the space between two adjacent joists, from the uppermost part of the joist to the lowermost part. Where the joists are generally rectangular and the projections on the joists are in the form of generally rectangular flanges for example, the additional shuttering may have a T-shape.

Preferably the joists are of reinforced or prestressed concrete.

Preferably the settable composition comprises concrete.

The invention includes a floor when constructed by the method according to the invention.

By way of example, specific embodiments of the invention will now be described, with reference to the accompanying drawings, in which: Figure 1 illustrates three different embodiments of floor according to the invention, looking in the direction of the longitudinal axes of the floor joists; Figure 2 is a side view of one form of additional shuttering; and Figure 3 is a perspective view illustrating in more detail one of the embodiments shown in Figure 1.

In order to construct a floor according to the invention, a plurality of elongate reinforced or prestressed concrete joists 10 are arranged in parallel but spaced-apart relationship, extending between the supporting walls 9 (see Figure 3) of a building.

The lower part of each joist has a pair of projecting flanges 11, one at each side. Shuttering is then positioned between each pair of adjacent joists, supported by the flanges. The left-hand portion of Figure 1 shows the use of one form of shuttering 12, the central portion of Figure 1 shows the use of another form of shuttering 13a, and the right-hand portion of Figure 1 shows the use of yet another form of shuttering 13b.

The shuttering 12 comprises lengths of cardboard. The width of each length of cardboard is greater than the distance between two adjacent joists and when the cardboard is placed in position it presents an upper surface which is curved upwardly as shown in Figure 1. By bending the cardboard under stress and restraining it in the bent condition, it is given sufficient strength to support wet concrete until it has set.

Once the cardboard has been placed in position, liquid concrete 14 is carefully poured on to the cardboard shuttering to fill the spaces between the joists as shown in Figure 1. The concrete is then left to set.

To prevent the joists from being forced apart by the restrained shuttering and the sideways load applied by the wet concrete, tie rods 18 having downturned ends 19 are hooked over the ends of the joists.

Once the concrete has set, it provides a series of arched infill blocks which have been formed in situ and which, because of their shape, and the fact that they are restrained by their solid contact with the sides of the joists, are stronger than conventional rectangular blocks.

The only function of the cardboard is to support the concrete until it sets. Once the concrete has set, it is quite capable of bearing all normal loads which may be applied to the floor and the cardboard need contribute nothing to the load bearing capacity of the finished floor.

In order to prevent the liquid concrete from flowing in the longitudinal direction of the joists, before the concrete has set, additional upwardly extending shuttering is placed at the ends of the joists.

For example a precast block 15 as shown in Figure 3 may be positioned at each end of a pair of joists, abutting the curved shuttering 12. Alternatively, a vertically extending piece of cardboard or other sheet material, of appropriate shape, may be used.

The shuttering 13a shown at the centre of Figure 1 comprises thin blocks or plates of polystyrene, concrete or breezeblock. These are placed in position as shown in Figure 1 and, as in the method already described, liquid concrete 14 is poured on to the plates or blocks. In this embodiment the plates or blocks 13a may contribute something to the load bearing capacity of the finished floor. Appropriately shaped shuttering may be used to contain the liquid cement at the ends of the joists. The plates or blocks have a curved upper surface to give the desired arched shape to the set concrete.

The shuttering 13b also provides infill members which are deeper adjacent to the joists, and hence stronger than a rectangular block, but the upper face of the shuttering 13b is chamfered rather than curved.

In some circumstances it may be desirable to use shuttering which fills the entire space between a pair of adjacent joists, from the upper surface of the joists to the lower surface of the joists, and an example of suitable shuttering is shown at 16 in Figure 2.

Where joists are supported by an internal wall for example, the joists of one room may not be precisely in register with the joists of another room. There may be a gap between the two floors extending along the internal wall. Concrete poured into the gap to fill it will flow down the gap, strike the top of the internal wall, and then flow sideways through the space 17 shown in Figures 1 and 3. To prevent concrete from being lost in this way it may be necessary to position adjacent to an internal wall the T-shaped shuttering 16 which will prevent any flow sideways from the internal wall into the space 17. One such piece of shuttering 16 is shown in position in Figure 3.

When a floor of given dimensions is to be constructed by the conventional method of placing standard size walling blocks between joists such as those shown at 10, it is very rare for an exact number of standard size blocks to be capable of making up the desired room dimensions. Usually it will be necessary, when using the conventional method, to use specially cut blocks along two sides of a room. Cutting blocks on site to precise dimensions can be lengthy and therefore expensive. The methods according to the invention described above can very conveniently be used in combination with the known method to manufacture infill blocks of any desired dimensions in situ.For example a floor may be largely constructed using conventional blocks of standard dimensions, as shown in Figure 3, the method according to the invention being used to fill the remaining spaces which cannot be filled by standard dimension blocks.

Of course the method according to the invention can be used to construct an entire floor if desired.

Once the wet concrete has set, the tie bars 18 can be removed for re-use and the joists are subsequently retained in position by building up the brickwork or blockwork as shown at 20 in Figure 3.

When the method according to the invention is used to fill a non-standard space between two blocks, for example as shown at 21 in Figure 3, there is a further advantage. The in situ concrete tends to key itself, frictionally at least if not me- chanically, to the adjacent blocks, thus deriving some support from the adjacent blocks. This advantage applies particularly where the gap to be filled is a gap of just a few centimetres. If the gap were to be filled by cutting a thin strip from a block, the strip would be very brittle and would derive no support from adjacent blocks.

The invention is not restricted to the details of the foregoing embodiments. For example the curved shuttering 12 may be constructed from any desired flexible material which can be bent to the desired shape, or any desired rigid material preformed to the desired shape. The plates or blocks 13 may also be constructed from any desired material.

The joists 10 need not have the profile shown and may have any other suitable profile which will provide adequate support for the shuttering.

Claims (14)

1. A method of constructing a floor, comprising the steps of arranging a plurality of joists in parallel but spaced- apart relationship, each joist having a pair of projections, one at each side, arranging shuttering between the joists, supported by the projections, pouring a settable composition on to the shuttering, to occupy the space between the joists, and allowing or causing the composition to set to provide infill members between the joists, the shuttering being such that the infill members have a depth which increases adjacent to the joists.

2. A method as claimed in claim 1, in which the shuttering has an upper surface which is curved upwardly so that the infill blocks take the form of an arch.

3. A method as claimed in claim 2, in which the shuttering comprises cardboard or other sheeting material, polystyrene or other plastics material, timber or timber substitute.

4. A method as claimed in claim 2, in which the shuttering comprises flexible sheet material which is bent under stress to provide the desired shape and is then restrained in the bent position.

5. A method as claimed in any one of the preceding claims, in which retaining means are provided to maintain the joists in position, against the sideways load applied by the unset material, at least until the material has set.

6. A method as claimed in claim 5, in which the retaining means comprises tie rods.

7. A method as claimed in claim 6, in which each end of each tie rod extends downwardly so that one end of each rod can hook over one joist and the other end of the tie rod can hook over an adjacent joist.

8. A method as claimed in any one of the preceding claims, in which additional upwardly extending shuttering is used to prevent the composition from flowing in the direction of the longitudinal axis of the joists before the composition has set.

9. A method as claimed in claim 8, in which the additional shuttering has a profile arranged to fill the space between two adjacent joists.

10. A method as claimed in claim 9, in which the joists are generally rectangular and the projections on the joists are in the form of generally rectangular flanges, the additional shuttering having a T-shape.

11. A method as claimed in any one of the preceding claims, in which the joists are of reinforced or prestressed concrete.

12. A method as claimed in any one of the preceding claims, in which the settable composition comprises concrete.

13. A method of construction a floor; constructed and arranged substantially as herein described, with reference to the accompanying drawings.

14. A floor when constructed by the method claimed in any one of the preceding claims.