The present invention further relates to apparatus and methods for producing concrete articles.

Conventional support apparatus for use in raising and supporting part of a structure is hydraulically operated to supply the tonnage force. However, conventional apparatus does not provide a"setting" fluid to provide a permanent support and also has the disadvantage that if a leak occurs in the apparatus, then failure of the support apparatus can occur. Conventional apparatus therefore does not

provide a permanent or semi-permanent support as the seals may leak causing failure of the apparatus.

This results in conventional apparatus only being suitable for a limited number of generally short- term applications.

Conventional apparatus and methods of producing concrete articles are based on pouring liquid concrete into a mould and allowing it to set.

The present invention, in one aspect, provides a method of producing a concrete structure in which fluid concrete is placed within a closed volume, pressure is applied to the concrete, and the pressure is maintained while the concrete cures.

The first aspect of the invention also provides apparatus for producing a concrete structure, comprising one or more members defining a closed volume for receiving fluid concrete, and means for applying pressure to the concrete within said closed volume while the concrete cures.

Preferably, the closed volume is defined by first and second members which interfit telescopically.

The second aspect of the invention also provides a method of supporting a structure, comprising providing support apparatus as defined in the preceding paragraph, pumping a settable fluid into said working volume to cause the first and second members to move to said extended position, and

allowing the settable fluid to set therein to maintain the first and second members in the extended position.

The settable fluid is preferably concrete, and more preferably self-compacting concrete.

Preferred features and advantages of the invention will be apparent from the following description and the claims.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig 1 is a schematic side view of support apparatus including the pump means; Figs 2A and 2B are cross-sectional front and side views of part of the support apparatus; Fig. 2C is a cross-sectional view of part of the support apparatus, detailing various parts and an upper and lower foot; Figs 3A to 3C are sequential perspective views of the operation of a valve which forms part of the apparatus of Figs 1; Figs 4A and 4B are schematic elevational views of the support apparatus being used in the forming of a bridge structure;

Figs 5A to 5C are schematic elevational views of the support apparatus being used in the forming of an alternative bridge structure.

Fig. 6 is a schematic side view of alternative support apparatus having pressurised concrete supplied by the pump; Fig. 7 is a schematic side view of the support apparatus of Fig. 6 having concrete supplied under gravity, which is then pressurised by ram means or any other form of pressurising or compaction; Figs. 8a and 8b are schematic side views of a further embodiment before and after pumping of concrete; and Figs. 9a and 9b are schematic side views of a final embodiment before and after placement of concrete.

Referring to Figs. 1 to 3, there is shown a support apparatus 10 which includes a pump 12 which has an inlet 14 and an outlet 16. The inlet 14 supplies fluid concrete to the pump 12 which then pumps the fluid concrete under pressure through an opening 17 and a valve 19 to a working volume 15 defined by first and second members 18 and 20 respectively.

The first and second members 18 and 20 are in the form of two telescopically arranged hollow cylinders and may be made of steel or plastics material such as polypropylene. The first member 18 is connected generally orthogonally at one end to the pump 12 through the opening 17 and valve 19, and is open at the other end. The second member 20 slidably fits telescopically within the opening in the first member 18.

The second member 20 is open at one end 22 and is closed at the other end 24. Closable exhaust vents 26 are located at the other end 24 of the second member 20.

A seal 21 is provided between the first and second members 18 and 20 to prevent concrete from leaking between the first and second members 18 and 20. The seal 21 is in the form of a bitumen bandage 21A which is taped to the outside of the second member 20. The bitumen bandage 21A is then wrapped in a PTFE plastics tape 21B or the like. The drawings schematically show a part of the seal 21, but it will be appreciated that the seal 21 may cover a portion or all of the outside surface of the second member 20. The PTFE tape 21B acts as a lubricant to allow the first and second members 18 and 20 to slide relative to one another.

The bitumen 21A deforms to adopt the shape of the gap between the first and second members 18 and 20, thus forming a seal.

As is best seen in Figs. 3A to 3C, the valve 19 is in the form of a gate valve and has a valve member 30 having a generally circular aperture 32. The aperture 32 is generally of similar dimension to the cross-sectional dimension of the hollow interior of the first and second members 18 and 20. The similarity of dimensions assists in transferring all of the tonnage force from the pump 12 to the first and second members 18 and 20.

The valve 19 has a slot 40 into which the valve member 30 is slidably inserted when the gate valve is open. The valve 19 is capable of being closed to retain the fluid under tonnage pressure within the first and second members 18 and 20. The valve 19 is closed by sliding a gate 42 across the opening 17 by way of a handle 38.

When the gate 42 slides to the closed position, the gate 42 abuts the valve member 30 and causes the valve member 30 to be pushed out of the slot 40.

The handle 38 is pushed or screwed to cause the gate 42 of the gate valve to close over opening 17. The closing of the gate 42 also causes the valve member 30 to slide out of the slot 40.

The first member 18 is provided with a guide 28 which serves to guide the fluid into the first member 18 and also assists in transferring the tonnage force from the pump 12 to the first and

second members 18 and 20. The guide 28 is moulded integrally with an inside surface of the first member 18. Alternatively, the guide 28 is a separate piece which is inserted into the first member 18. The guide 28 may be made of concrete.

As is best seen in Fig. 2C, the apparatus 10 may also be provided with an upper foot 50 and a lower foot 52. These feet 50,52 are attached at either end of the apparatus 10 to allow the apparatus 10 to more easily connect to surrounding surfaces.

In use, before pumping, the first and second members 18 and 20 are in a retracted position, wherein the second member 20 is generally fully within the first member 18 and the hollow space within the first and second members 18 and 20 defines the working volume 15. The first and second members 18 and 20 are placed under a structure to be lifted and supported.

The exhaust vents 26 are open to allow air to be expelled from the working volume 15 and the valve 19 is open.

Fluid concrete, preferably in the form of self- compacting concrete, is supplied to the pump 12 and is subsequently pumped under tonnage pressure through the opening 17 and valve 19 into the working volume 15. The guide 28 assists in directing the fluid concrete into the working volume 15. In one embodiment, the pump supplies a pressure of 1100 PSI and can lift 10 to 15 tonnes with an ultimate load bearing capacity in excess of 50 tonnes.

The working volume 15 fills with fluid concrete, the air in the working volume 15 being expelled from the air vents 26.

When the fluid concrete completely fills the working volume 15 with the first and second members 18 and 20 in the retracted position, the air vents 26 then close and the tonnage pressure supplied by the pump 12 causes the first and second members 18 and 20 to move from the retracted position towards an extended position wherein the second member 20 telescopically extends out of the first member 18.

This extension together with an adequate tonnage force supplied by the pump 12 is capable of lifting a structure.

When the structure has been raised to the required height, or the second member 20 is fully extended from the first member 18, the valve 19 is closed and the pumping stopped. The fluid concrete within the working volume 15 is held under tonnage pressure in the working volume 15 and then sets within the working volume 15, thus providing a permanent or semi-permanent support.

In a modification of the forgoing embodiment, the members 18 and 20 are interconnected by a helical connection such as studs on one engaging with a helical track on the other. In this way, the second member 20 will rotate as it is extended from the

first member 18. The end of the second member 20 may be provided with angled cutting vanes which can be used to bore into subsoil or the like, allowing the apparatus to be used to create its own foundation or pile.

Illustrated in Figs. 4A & 4B is an example of how a bridge is erected using the apparatus of the present invention. The base 112 of a bridge 110 is positioned to the required level and the apparatus 10 is inserted at either end of the base 112. The second member 20 is extended into a river bank 114 and the liquid concrete mixture deployed and set after closure of the valve 19. This is repeated at each end of the base 112. A support frame 116 and road 118 is lowered to span the width of the base 112. In a similar method as described above, the apparatus 10 is inserted at either end of the road 118. The second member 20 of the apparatus 10 is extended into the river bank 114 and the liquid concrete mixture deployed and set after closure of the gate valve 19.

Illustrated in Figs. 5A to 5C is an example of a how an alternative bridge (bowframe bridge) is erected using the apparatus of the present invention. The extension of the second members 20 causes a tensioning element 210 to tighten which causes surface 220 to arch into position.

It has been found that concrete which is contained under pressure while setting and curing is stronger

than conventionally placed concrete. This allows supporting members to be of smaller dimensions than would be required with poured concrete. This factor is also utilised in the following embodiments of the invention.

Fig. 6 shows an apparatus 300 where fluid concrete is pumped by the pump 12, through the valve 19 into a working volume 315 defined by a container member or mould 310.

The fluid concrete is pumped under pressure into the working volume 315, where any air therein is expelled through air valves 312 located at appropriate points around the mould 310 where there is likely to be trapped air.

Once all the air is expelled, the air valves 312 will close and the pump 12 will pressurise the fluid concrete within the working volume 315.

When pressurised, closure of the valve 19 will retain the pressurised fluid concrete within the working volume 315 where curing of the pressurised fluid concrete will take place over a duration of time.

If desired, the mould 310 may be removed after the pressurised fluid concrete has cured.

Alternative apparatus 350, as shown in Fig. 7, has the fluid concrete being gravity fed into the working volume 315 by gravity feeding means 360.

The gravity feeding means 360 comprises ram means 362 which may be of the form of a hydraulic ram, jack, gearing, or other means such as compaction within the mould itself, to apply a pressure to, and thus pressurising, the fluid concrete within the working volume 315. In this way the fluid concrete can be thought of as being post-pressurised concrete.

In use, the fluid concrete is gravity fed into the working volume 315 by the gravity feeding means 360.

When a suitable volume of fluid concrete is within the working volume 315, the ram means 362 is selectively operated to extend and push the fluid concrete into the working volume 315. Any air within the mould 310 will be expelled through air valves 312 located at appropriate points around the mould 310 where there is likely to be trapped air.

Once all the air is expelled, the air valves 312 will close, and the ram means 362 will continue to extend and push the fluid concrete into the working volume 315, thus pressurising the fluid concrete within said volume 315.

Closure of the valve 19 will retain the pressurised fluid concrete within the working volume 315 where

curing of the pressurised fluid concrete will take place over a duration of time.

If desired, the mould 310 may be removed after the pressurised fluid concrete has cured.

The pressurised concrete, as described in Figs. 6 and 7, can be further strengthened by the use of pre-stressed or post-stressed steel fixings within the concrete. Fig. 8 shows such an arrangement.

First and second members 410 and 412 interfit telescopically to define a working volume 414.

Steel reinforcing rods or cables 416 are attached at one end to the first member 410 and at the other end to the second member 412, and have a length such they are not initially under tension. Concrete is supplied under pressure via an entry port 418 causing the first and second members to undergo extension. It will be understood that air release valves (not shown) may be provided as before. The concrete is pumped until the rods or cables 416 are under a desired tension, at which point the entry port is closed by a closure plate indicated at 420 and the concrete is allowed to cure while under pressure.

The fluid can also be pressurised or compacted by sealing the fluid into the mould and then reducing the working volume of the mould. In Fig. 9 first and second members 510 and 512 interfit telescopically to define a working volume 514. Steel reinforcing rods 516 pass at one end through the

first member 510 and at the other end through the second member 512, with either end being threaded and provided with a nut 522 bearing on the respective first or second member.

Concrete is supplied by gravity via an entry port 518. It will b understood that air release valves (not shown) may be provided as before. The concrete is supplied until the working volume 514 is full, at which point the entry port 518 is closed by a closure plate indicated at 520 to seal the working volume 514. The nuts 522 at either or both ends are then tightened, causing the first and second members to retract and subjecting the trapped concrete to pressure. The tightening is continued until a desired pressure is achieved, and the concrete is allowed to cure while under pressure.

Modifications and improvements may be made to the foregoing without departing from the scope of the present invention. For example, the pump 12 may not be connected orthogonally to the first member 18 but alternatively could be connected at any angle. The second member 20 may fit telescopically on the outside of the first member 18. Whilst a gate valve 19 is shown in the embodiment, the valve 19 may be of a different type, for example a one way valve.

The support apparatus may be used in conjunction with concrete pylons, ties, struts, steel fixings, H-beams or similar. The apparatus can be used alone or a number of working volumes may be defined which

work together to create foundations of buildings (in particular quick assembly bridges), supports or fixings for bridges, mining supports and other underground applications or for stabilisation of earth (for example, where subsidence has occurred).

The apparatus can also be used in applications such as securing roads to the sides of hills, creating roof structures or used to raise floors of buildings during construction, i. e. where the floor is produced at ground level then each new floor raised pushes the upper floors higher.

The apparatus can also be used in rescue operations from damaged or collapsed buildings such as after an earthquake, or as a support in a mine during a mining rescue, by raising rubble or securing supports.

Alternative setting materials may be used other than concrete, such as epoxy resins, resins, clay or slip. Also, the setting material may include additives which assist in the setting of the material in a confined space under a tonnage force.

Other additives such as pulverised fuel ash, sand, slip, clay or the like can be added to assist flow under pressure and to increase the strength of the material when set. Other viscous additives may be added to reduce the amount of water required in the fluid and to aid flow into the working volume 15 and to minimise shrinkage within the working volume 15 and to control the setting rate of the fluid.

The first and second members 18 and 20 may alternatively be formed of any plastics material such as polymer plastics or may be formed of alloy, ferrous or non ferrous metal, carbon, concrete or any other like material.

The apparatus may be attached to another member, such as a tubular section, and this other member is allowed to fill before the fluid concrete fills the working volume 15. This creates a one piece solid cast concrete structure, such as a bridge.

The apparatus may be linked together or double ended. Also, whilst two members 18 and 20 are described to act telescopically, it is to be understood that multiple members could also be used which act telescopically.

A number of apparatus may be tied, secured or braced together in any form or configuration and may include an internal steel fixing framework to further strengthen the support.

The first and second members 18 and 20 may be made any length, shape or size and may operate vertically, horizontally, or at an angle. For example, the first and second members 18, 20 may be of square, hexagonal or triangular cross-section.

Whilst the embodiments describe an air filled working volume 15, alternatively, the working volume

15 may be water filled or filled with any other suitable fluid.

In an alternative seal, the inside surface of the first member 18 is coated, by spraying PTFE plastics material or similar. The second member 20 is then inserted into the inside of the first member 18, and the gap between the first and the second members 18 and 20 is filled with molten bitumen which then solidifies to form the seal. The first and second members 18 and 20 can move relative to one another by way of the PTFE or similar acting as a lubricant.

Also, whilst bitumen is described in the embodiments, similar materials could be used.

Further seals may be of the form of caulking cotton to prevent leakage into the first member 18.

Steel can be incorporated into the moulds to provide reinforced concrete and pressurised concrete.

The mould can be of any shape, for example could be shaped to form bricks, paving, lintels, struts, beams, supports, pillars, columns and also other shapes, for example garden furniture or street furniture such as chairs, benches and street lights or other ornamentation.