AU2020223674A1 - A process and apparatus - Google Patents

Abstract

The present invention relates to a method for raising foundations of a building. The method may include a first lifting step of lifting a section of foundation of a building; and injecting a flowable material under the foundation. The flowable material may harden to underpin the section of foundation of the building. The invention also relates to an apparatus. 21 1/5 A)- Assessing the building and determine the section of the foundation to be raised and underpinned. B)- Evaluating the total lift of the section of the foundation required.. C)- Attaching anchors at lifting points spaced atintervals along the section of the foundation identified. D)- Assemblying a first lift including one or more actuator(s) and attach the actuators to the anchors. E)- Conducting a first lifting step by operating the first lift to form a pocket between the section of the foundation and a subsided bed on which the section of foundation sits. F)- Operating a first controller to adjust the first lifting force applied to the lifting points. G)- Estimating the lift of the section of the foundation provided by the first lifting step, which may include estimating the volume of the pocket. H)- Injecting a flowable material into the pocket and allowing the flowable material to harden in the pocket which underpins the section of the foundation. I)- Pressurising the flowable material into pockets in order to apply second lifting force to the section of foundation, thereby lifting the section of the foundation to a second lifted position. J)- Operating a second controller to: Adjust the pressure of the flowable material supplied to the pocket. Adjust the flowrate of the flowable material. Measure the volume of the flowable material. FIGURE 1

Description

1/5

A)- Assessing the building and determine the section of the foundation to be raised and underpinned.

B)- Evaluating the total lift of the section of the foundation required..

C)- Attaching anchors at lifting points spaced atintervals along the section of the foundation identified.

D)- Assemblying a first lift including one or more actuator(s) and attach the actuators to the anchors.

E)- Conducting a first lifting step by operating the first lift to form a pocket between the section of the foundation and a subsided bed on which the section of foundation sits.

F)- Operating a first controller to adjust the first lifting force applied to the lifting points.

G)- Estimating the lift of the section of the foundation provided by the first lifting step, which may include estimating the volume of the pocket.

H)- Injecting a flowable material into the pocket and allowing the flowable material to harden in the pocket which underpins the section of the foundation.

I)- Pressurising the flowable material into pockets in order to apply second lifting force to the section of foundation, thereby lifting the section of the foundation to a second lifted position.

J)- Operating a second controller to:

Adjust the pressure of the flowable material supplied to the pocket. Adjust the flowrate of the flowable material. Measure the volume of the flowable material.

FIGURE 1

A METHOD AND APPARTUS RELATED APPLICATION

[0001] The present application claims priority to Australian provisional application number 2019903106 filed on 26 August 2019, the specification of which is hereby incorporated into the present specification.

FIELD OF THE PRESENT INVENTION

[0002] The present invention relates to a method and apparatus for raising foundations of a building. The method and apparatus may be used for underpinning the foundations of a building. The method and apparatus can be used to underpin a range of buildings including, but are by no means limited to, buildings having concrete foundations, such as concrete trench foundations for external or internal brickwork, and concrete slab foundations.

BACKGROUND OF THE INVENTION

[0003] Buildings may require underpinning when the water content in the ground, either under the building or around the outside of the building changes. For instance, for foundations in the range of 40cm to 100cm in depth, trees planted close to a building or a broken water pipe can significantly change the water content of the ground. In clay soils, drying of the soil usually results in contraction of the ground compared to the regions of the ground having higher water content. When different regions of the ground become dry or wet, sections of the foundation can either drop or rise. This can lead to cracking of walls of the building and an increased risk of structural failure if the cracking is severe enough, and precautions are not taken.

[0004] One approach for rehabilitating subsided foundations is to inject a two-part polymeric mixture beneath the foundations which expands and hardens, thereby having the potential to lift and stabilising the foundation. However, this approach is prone to several difficulties, including variable degrees of expansion, and the direction in which the mixture expands is uncontrollable. This can result in several outcomes, including the ground around the footing swelling or rising without the foundation being restored to its original level.

[0005] It is therefore an object of the present invention to provide an alternative method and assembly.

SUMMARY OF THE PRESENT INVENTION THE METHOD

[0006] The present invention relates to a method of raising a foundation of a building, the method includes the steps of:

a first lifting step of lifting a section of foundation of the building, wherein the first lifting step includes operating an actuator to apply a first lifting force and lift the section of foundation to a first lifted position; and

a second lifting step of lifting the section of foundation from the first lifted position to a second lifted position that is higher than the first lifted position, wherein the second lifting step includes injecting flowable material under the section of the foundation which raises the section of the foundation of the building.

[0007] The first lifting step may form a pocket between the section of foundation and a bed on which the foundation sits.

[0008] The second lifting step may include injecting the flowable material into the pocket and allowing the flowable material to harden which underpins the section of the foundation.

[0009] The second lifting step may include injecting the flowable material into the pocket until the section of foundation has been lifted to the second lifted position.

[0010] The first lifting step may be carried out without excavating a lower segment of the foundation. That is to say the pocket may be formed without excavation of the pocket. The pocket may be formed entirely by lifting the section of foundation.

[0011] The term "pocket" may relate to any spacing formed between the foundation and the bed on which the foundation sits that can receive the flowable material. For example, when the first lifting step lifts the foundation, air, debris, water, mud, silt or other shiftable material may be drawn into and occupy the pocket, or part of the pocket, prior to the step of injecting the flowable material into the pocket. Injecting the flowable material into the pocket may at least partially displace the shiftable material from the pocket.

[0012] However, it is intended that injecting the flowable material may displace most of the shiftable material, thereby maximising the volume of the pocket.

[0013] The first lifting step may include applying a lifting force to multiple lift points to the section of foundation.

[0014] The lift points may be spacing apart along the length of the section of foundation. For example, the spacing between the lift points may be in the range of 150mm to 1000mm apart, suitably in the range of 250 to 700mm apart, ideally in the range of 300 to 500mm apart, and even more ideally approximately 400mm apart.

[0015] The first lifting step may include controlling a first lifting force applied to the section of foundation at the lifting points.

[0016] Controlling the first lifting force may include operating a first controller.

[0017] The first lifting force applied at each lifting point may be up to 15 tonne, and suitably in the range of 6 to 10 tonne, and ideally approximately 8 tonne.

[0018] Controlling the first lifting force may include applying the same lifting force at each of the lifting points.

[0019] Controlling the first lifting force may include adjusting the lifting force for each lifting point individually. The lifting force applied at each lifting point may be different.

[0020] Controlling the first lifting force may include applying different forces at each of the lifting points based load points of the building on the section of foundation.

[0021] Controlling the lifting force may include operating an actuator, such as a jack that applies the first lifting force at each lifting point. The jack may, for example, be a mechanical jack, a hydraulic jack, or a pneumatic jack.

[0022] The first lifting step may lift the foundation by any height. Moreover, it will be appreciated that the height to which the foundation is lifted will depend on the section of foundation being lifted, the downward load on the foundation including the structure of the building and whether the building is single storey or multi-storey, the length of the section of foundation, and spacing between the section of foundation being lifted and adjacent parts of the foundation that are not being lifted. The depth of the pocket formed, and therefore the height to which the foundation is lifted may vary and will be smaller moving toward parts of the foundation that are not being lifted.

[0023] The first lifting step foundation may lift the section of foundation by any amount to a first lifted position. For example, the first lifting step may lift the section of foundation by an amount up to 300 mm, and suitably in the range of 5 to 100 mm.

[0024] The method may also include controlling the height by which the foundation is lifted in the first lifting step. For example, the height to which the foundation is lifted may increase moving away from a section of foundation that is not being lifted.

[0025] The first lifting step may include fitting anchors to the foundation at spacings along the foundation. Each anchor may form one of the lifting points. Fitting the anchors may include boring holes into the foundation for receiving tensile bars. Examples of tensile bars include bars sold under the Tradename TieLock by advanced concrete technologies which have an adjustable block or nut that can be moved along the bars as desired.

[0026] Fitting the anchors may include inserting the tensile bar into each bore and fixing the tensile bar in each bore using an adhesive. The adhesive may be any suitable adhesive including single part adhesives and two-part adhesives.

[0027] The method may include estimating the volume of the pocket as a function of a cross-sectional area of the section of foundation, such as the horizonal cross sectional area, and the first lifted position of the foundation by the first lifting step.

[0028] The second lifting step of lifting the section of foundation to a second lifted position which has a height that is higher than the first lifted position.

[0029] The second lifting step includes pressurising the flowable material that is injected under the foundation to apply a second lifting force.

[0030] The second lifting step includes pressurising the flowable material that is injected under the foundation to apply a second lifting force.

[0031] The second lifting step may include controlling the pressure of the flowable material injected under the foundation to control the second lifted position.

[0032] The second lifting step may increase the pocket to an expanded pocket.

[0033] The second lifting step may lift the section of foundation to a height that restores the height the section of foundation relative to the adjacent segments of the foundation.

[0034] The second lifting step may include controlling a second lifting force applied to the section of foundation.

[0035] The second lifting force may be evenly distributed along the section of foundation.

[0036] The second lifting force may be evenly applied along the section of foundation.

[0037] The second lifting force may be upto 15 tonne per lineal metre, and suitably in the range of 6 to 10 tonne lineal metre, and ideally approximately 8 tonne per lineal metre of the section of foundation.

[0038] The second lifting step may include pressurising a fluid injected under the foundation to apply a second lifting force to the section of foundation.

[0039] The fluid may or may to be used to stabilize the section of foundation. For instance, in one example, the fluid may be the flowable material that hardens in the pocket. In this situation, the steps of injecting the flowable material into the pocket and the second lifting step may be carried out simultaneously, concurrently or disjunctively.

[0040] The second lifting step may include pressurising the flowable material that is injected in the pocket and controlling the pressure of the flowable material in the pocket to control the second lifting force of the second lifting step. The pressure of the flowable material may be controlled prior to the flowable material hardening.

[0041] The second lifting step may include pressurising the flowable material that is injected and controlling the pressure of the flowable material to control the height of the second lifted position.

[0042] For example, the second lifting step may include controlling the pressure in the flowable material in the pocket to a pressure up to 300 psi to adjust the second lifting force. For instance, the controller may control the pressure to a range of 100 to 150 psi to adjust the second lifting force.

[0043] The second lifting step may include operating a pump that pumps the flowable material and/or a valve that regulates the flow of the flowable material, and in turn, controls the pressure of the flowable material.

[0044] The second lifting force applied by the flowable material will be a function of the pressure of the flowable material and the area of the section of foundation that is contacted by the flowable material.

[0045] The second lifted position may be higher than the first lifted position. For example, the second lifting step may lift the section of foundation by any amount above the first lifted position. For example, the second lifting step may lift the section of foundation by an amount in range of 5 to 300mm, and suitably in the range of 10 to 200mm.

[0046] The second lifting step may lift the foundation by an amount required to restore the height of the foundation.

[0047] The step of injecting the flowable material may include injecting the flowable material under the foundation until the section of foundation has been lifted to the second lifted position. Injecting the flowable material under the foundation may include injecting the flowable material into the pocket. Ideally, the section of foundation has been restored to the required height at the second lifted position.

[0048] The step of injecting the flowable material may include measuring the volume of the flowable material injected.

[0049] The method may include estimating the volume of the flowable material to be injected in the injecting step, as a function of a cross-sectional area of the section of the foundation, such as the horizonal cross-sectional area, and the total of first and second lifted positions.

[0050] The method may include monitoring the height of the section of foundation during the injecting step and stopping the injecting when the section of foundation has reached a predetermined height, namely the second lifted position.

[0051] The method may include determining the height of the second lifted position, and monitoring the height of the section of foundation during the second lifting step and stopping the second lifting step when the section of foundation has reached the second lifted position.

[0052] During the second lifting step, the first controller may also be operated so that the first lifting force is either:

i) maintained during the second lifting step, ii) reduced during the second lifting step, or iii) stopped during the second lifting step.

[0053] The flowable material may be any suitable hardenable material, for example, the material hardens in the ground, does not decompose in the ground, and has suitable load bearing properties once hardened to underpin the building. The flowable material may be concrete suitable for use as inground foundations.

[0054] In another example, the second lifting step may include injecting a working fluid into the pocket, and the method may include pressurising the working fluid in the pocket to lift the section of foundation to the second lifted position. The method may include a step of supporting the section of foundation in the second lifted position and withdrawing the working fluid from the pocket. Once the working fluid has been withdrawn from the pocket, the step of injecting the flowable material into the pocket may be carried out and allowed to harden.

[0055] The present invention relates to a method of underpinning a foundation of a building, the method includes the steps of:

a first lifting step of lifting a section of foundation of a building to form a pocket between the section of foundation and a bed on which the section of foundation sits; and

injecting a flowable material into the pocket and allowing the flowable material to harden in the pocket which underpins the section of foundation of the building.

[0056] The present invention relates to a method of underpinning a foundation of a building, the method includes the steps of:

a first lifting step of lifting a section of foundation of a building to form a pocket between the section of foundation and a bed on which the section of foundation sits, wherein the first lifting step includes operating an actuator to apply a first lifting force and lift the section of foundation to a first lifted position;

a second lifting step of lifting the section of foundation from the first lifted position to a second lifted position that is higher than the first lifted position; and injecting a flowable material into the pocket and allowing the flowable material to harden in the pocket which underpins the section of foundation of the building at the second lifted position.

[0057] The present invention relates to an apparatus for raising a foundation of a building, the apparatus includes:

a first lift assembly including at least one actuator that is operable to apply a first lifting force that can lift a section of foundation of the building toa first lifted position; and

a second lift assembly that is operable to apply a second lifting force that can lift the section of foundation from the first lifted position to a second lifted position that is higher than the first lifted position, wherein the second lifting assembly includes an injector that injects a flowable material under the section of the foundation which raises the section of the foundation to the second lifted position.

[0058] The first lifting assembly may form a pocket between the section of foundation and a bed on which the foundation sits at a first lifted position, and the flowable material can harden after being injected into the pocket and thereby underpin the section of foundation of the building.

[0059] The first lift assembly may include multiple lifting points spaced along the length of the foundation at which first lifting forces can be applied to the foundation.

[0060] The lifting points may include an anchor that is embedded in the foundation. The anchor may be any suitable anchor including a screw anchor, a rock bolt, an elongate bar, or a Z-bar that is located in a bore in the foundation. The bar may have retention formations such as ribs or barbs that can be embedded in the bore. The bar may be adhered in the core using any suitable adhesive.

[0061] The bar may be embedded in the section of foundation by any suitable amount, and ideally by an amount in the range of 100 to 500 mm, and ideally by an amount in the range of 100 to 300 mm.

[0062] The first lift assembly may include an actuator that applies the first lifting force to each lifting point. Each lifting point may have an actuator.

[0063] In one embodiment the first lifting forces applied at the lifting points by the actuators may be individually adjusted by a first controller. For instance, the force applied at each lifting point may be a function of the position of the lifting point along the section of the foundation. The first lifting force at each consecutive lifting point may increase moving along the section of foundation in a direction away from adjacent parts of the foundation that do not include underpinning.

[0064] Similarly, the first lift assembly can lift the section of foundation to a first lifted position along the length of the section of foundation that varies along the foundation. The first lifted position may increase moving along the section of foundation in a direction away from adjacent parts of the foundation that are not being underpinned.

[0065] The actuator(s) may have a hydraulically operated ram that is adjusted by a first controller.

[0066] The first lifting force of each actuator may be adjusted by the controller for each actuator.

[0067] In one example, the first controller is operable so that the first lifting force may be the same for each actuator. In another example, the first controller is operable so that the first lifting force can differ for each actuator.

[0068] In one example, the first controller is operable so that the first lifted position of the section of foundation may be same at each actuator. In another example, the first controller is operable so that the first lifted position can differ along the section of foundation.

[0069] Each actuator may be directly connected to one of the anchors.

[0070] The first lift assembly may include a bracket having a first member positioned parallel to a wall on the section of foundation, the anchor(s) may be connected to a second member extending outwardly from the first member, and the actuator(s) may act on the second member to apply to the lifting force to the anchor.

[0071] The apparatus may include a second lift assembly that lifts the section of foundation from the first lifted position to a second lifted position.

[0072] The second lift assembly may be any suitable device including a mechanical lifting device, but suitably includes supplying a fluid to the pocket and pressuring the fluid.

[0073] The injector may be operable as the second lift assembly, whereby the injector supplies the flowable material, at a pressure, into the pocket, and the pressurise of the flowable material acts as a second lifting force on the section of foundation.

[0074] The second lift assembly may include a reservoir of the flowable material, a pump that receives the flowable material from the reservoir, and a conduit for conveying the flowable material from the pump, the conduit has an opening that, when in use, supplies the flowable material into the pocket.

[0075] The second lift assembly may include a plurality of the conduits for supplying the flowable material at internals along the section of foundation.

[0076] Ideally, the pocket extends along the section of foundation.

[0077] The second lift assembly may include multiple conduits for supplying the flowable material at spacings along the section of foundation.

[0078] The injector may include a controller that allows a user to do one or more of the following.

i) Adjust the pressure of the flowable material discharged from the pump, and thus adjust the pressure of the flowable material supplied by the conduit into the pocket. ii) Adjust the flowrate of the flowable material discharged from the conduit. iii) Measure the volume of the flowable material discharged from the conduit. For example, by adjusting a valve that in the conduit. iv) Turn the pump ON and/or OFF.

[0079] The present invention also relates to an apparatus for underpinning a foundation of a building, the apparatus includes: a first lift assembly that lifts a section of foundation of a building to form a pocket between the section of foundation and a bed on which the foundation sits; and

an injector that injects a flowable material into the pocket, where the flowable material can harden and thereby underpin the section of foundation of the building.

[0080] The present invention also relates to an apparatus for underpinning a foundation of a building, the apparatus includes:

a first lift assembly including an actuator that is operable to apply a first lifting force that lifts a section of foundation of the building to form a pocket between the section of foundation and a bed on which the foundation sits at a first lifted position;

a second lift assembly that is operable to apply a second lifting force that lifts the section of foundation from the first lifted position to a second lifted position that is higher than the first lifted position; and

an injector that injects a flowable material into the pocket, where the flowable material can harden and thereby underpin the section of foundation of the building.

[0081] The apparatus described throughout this specification may also include any one or a combination of the features of the method described herein. Similarly, the method described throughout this specification may include any one or a combination of the features of the apparatus described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0082] A preferred embodiment of the present invention will now be described with reference to the accompanying drawings which can be summarised as follows.

[0083] Figure 1 is a block diagram illustrating the method step for underpinning a subsided section of a foundation in accordance with the preferred embodiment.

[0084] Figure 2 is schematic perspective view of a section of foundation, in the form of a trench foundation for brickwork. The foundation is lifted from level A in which the foundation has subsided, to level B by a first lift step, and then from level B to level C in a second lifting step for underpinning the section of foundation.

[0085] Figure 3 is a schematic cross-sectional view of the foundation shown in Figure 2. An apparatus is used to lift the section of foundation in a first lifting step to create a pocket between the section of foundation and a bed on which the foundation sits. The foundation may then be lifted in a second lifting step using hydraulically pressure of a flowable material. The second lifting step may also include a mechanical lifting action for lifting the foundation.

[0086] Figure 4 is a schematic plan view of a foundation in a ninety degree corner, in which the mechanical lifts are controlled by a first central controller, and a hydraulic lift is controlled by a second controller.

[0087] Figure 5 is a schematic cross-sectional view of the foundation in Figure 4 in which a subsided section of the foundation, denoted by level A, is lifted to first lifted position, denoted by line B, and then lifted further to a second lifted position, denoted by C.

DETAILED DESCRIPTION

[0088] A preferred embodiment of the present invention will now be described in the following text which includes reference numerals that correspond to features illustrated in the company figures. To maintain clarity of the figures, however, all of the reference numerals are not included in each figure.

[0089] The method according to a preferred embodiment may include step A), see figure 1, which includes conducting a preliminary assessment of a building for signs that indicate its foundation may have subsided, for example, by looking for superficial or structurally significant cracks, and determining whether a section of foundation 10 should be raised and underpinned. The preliminary assessment may also include step B), see figure 1, which includes evaluating the degree by which the section of foundation 10 has subsided.

[0090] Once a section of foundation 10 has been identified, the method includes step C), see figure 1, which includes installing anchors at lifting points 14 spaced at intervals along the section of foundation 10. Depending on the type of anchors, installing the anchors can include drilling one or more bores up to 400 mm deep into the foundation 10 at spaced intervals and inserting high tensile lifting bars 12 into the bores, as best depicted in figure 4. Ideally the lifting bars 12 have ribs or barbs and an adhesive can be used for securing the bars 12 in position in the bores. As can best be seen in figure 3, the bars 12 extend above ground level and a first lift assembly 11 is erected.

[0091] The method includes step D), see figure 1, which includes installing the first lift assembly 11 by locating a lifting bracket 13 adjacent to the brickwork or wall of the building 20 above the section of foundation 10. The lifting bracket 13 has a first flange extending parallel to the brickwork and a second flange extending laterally to the first flange. Figure 3 illustrates the situation in which two of the lifting bars 12 are inserted into the foundation at a single lifting point 14 and the upper end of the lifting bars 12 extend through the second flange of the lifting bracket 13 and a stop member 16 is fitted to the lifting bars 12, locating the lifting bracket 13 relative to the lifting bars 12. An actuator in the form of a hydraulically driven ram and cylinder jack 15 is arranged beneath and applies a first lifting force, schematically depicted in figure 2 by arrows Fl. The first lifting forces F1 of the jacks 15 may have a magnitude of up to 10 tonne at each lifting point 14.

[0092] The method includes step E), see figure 1, which is a first lifting step in which the section of foundation 10 is lifted from a subsided position, graphically depicted in figures 2, 3 and 5 by the dotted line "A" to a higher level, namely the first lifted position depicted by the dotted line "B". The first lifting step may lift the section of foundation 10 to an desired height, for example, a height in a range up to 200 or 300 mm. Ideally however the first lifting step lifts the section of foundation 10 at a height in the range of 50 to 100 mm, creating a pocket 31 at the base of the section of foundation 10.

[0093] The first lifting step, step E) in figure 1, may include operating a first controller 18 to adjust either one or a combination of: i) the first lifting force F1 applied at each of the lifting points 14, and ii) the height of the first lifted position "B" relative to level "A" at each of the lifting points 14. It will be appreciated that the first lifted position "B" may vary and, for example, increase moving in a direction away from the section of foundation 10 that has not subsided. The first controller 18 may, for example, control the pressure of a hydraulic fluid fed to each of the jacks 15 at the lifting points 14 as depicted in figure 4. First lines 30 supply the hydraulic fluid to the jacks

[0094] One of the purposes of the first lifting step, i.e. step E) in figure 1, is to create a void or pocket 31 between the section of foundation 10 and the subsided bed or earth 29 on which the section of foundation 10 sets. As the section of foundation 10 is lifted during the first lifting step, shiftable material such as water, silt or mud may be drawn into the pocket 31. However, it will be appreciated that the shiftable material may be displaced from the pocket 31 thereafter. In any event, it is envisaged that the method of the present invention would preferably not include excavating the earth 29 about or beneath the section of the foundation 10. By not excavating the pocket 31, the pocket 31 essentially forms a closed chamber at the bottom of the section of foundation 10 for receiving a flowable material. If desired, the method may include estimating the height over which the section of foundation 10 is lifted between the subsided level "A" and the first lifted position "B". It therefore follows that the volume of the pocket 31 may also be estimated.

[0095] The method includes injecting a flowable material into the pocket 31, identified as step H) in figure 1. In the event that the height by which the section of foundation 10 has been raised by the first lifting step, for instance if it was determined that the section of foundation 10 needed to be lifted by a particular height and that the first lifting step substantially achieved that lift, step H) may include allowing the flowable material to harden in the pocket 31 which underpins the section of foundation 10.

[0096] In the event that the first lifted position "A" is lower than the overall lift required, the method may include pressurising the flowable material in the pocket, in accordance with step I) of figure 1 in a second lifting step. By pressurising the flowable material in the pocket 31, the flowable material will apply a second lifting force, denoted by F2 in figure 2, to the section of foundation 10. It will be appreciated that pressurising the flowable material will need to be carried out prior to the flowable material hardening. The magnitude of F2 will be a function of the pressure of the flowable material and the area of the section of foundation 10, for example, in a horizontal plane, that is contacted by the flowable material. For example, pressurising the flowable material to a pressure in the range of up to 200 psi which can generate a lifting force in a range of up to 10 tone per lineal metre of the section of the foundation, assuming the foundation has a consistent cross sectional area. On the advantages of using the flowable material to apply the second lifting force F2, is that the second lifting force will be distributed over the surface of the section of foundation 10, thereby minimising the risk of localised failure points in the section of foundation 10.

[0097] Step J) of the method, as shown in figure 1, includes operating a second controller 25 to achieve any one or a combination of the following:

* Adjusting and controlling the pressure of the flowable material supplied to the pocket 31. * Adjusting and controlling the flow rate of the flowable material supplied to the pocket 31. * Estimating the volume of the flowable material supplied to the pocket 31.

[0098] During the second lifting step, the first controller 18 may also be operated so that the first lifting assembly 11, and in particular the jack 15 remain in contact with the ground. That is to say, the first controller 18 may be operated to extend the jacks 15 so as to either: i) maintain the first lifting force during the second lifting step, ii) reduce the first lifting force during the second lifting step, or iii) stop the first lifting force during the second lifting step.

[0099] The apparatus of the preferred includes multiple lifting points 14, best seen in figure 4, that are located at spaced intervals of approximately 300 to 400 mm apart along the section of foundation 10. Each lifting point 14 includes at least one lifting bar 12 fixed in foundation by an adhesive, such as a two-part expoxy adhesive sold under the brand, Sika@ Anchor 3+by Sika Australia Pty Ltd. The bar 12 may be any Tensile bar such as Tielock rebar available from Actech Australia having a stop member 16 that threads onto or engages the teeth on the bar 12.

[0100] A first lifting assembly 11 may be installed at each lifting point 14. The first lifting assembly 11 also includes a lifting bracket 13, as described above, to which the bar 12 is connected, and a lifting jack 15, suitably a hydraulic jack applies the first lifting force F1, shown in figure 2 to the lifting bracket 13. The jacks 15 at each lifting point 14 may be connected to central first controller 18 which controls the pressure of the hydraulic fluid that powers the jacks via first line 30, and in turn, controls the first lifting forces F1 at the lifting points 14 and travel of each lifting jack 15. The lifting jacks 15 may, for example, be capable of lifts of 10 tonne each. A first lifting step is carried out by operating the jacks to create the pocket by lifting the foundation from subsided point a to level "B".

[0101] The apparatus also includes an injector that injects a flowable material in the form of concrete into the pocket 31. The injector has a reservoir 21 for containing the concrete, a second pump 22 that the receives the concrete and a conduit 24 having an end that the can be locate in the pocket 31 for supplying the flowable material. In addition to conveying the concrete, the second pump 22 can also pressurise the concrete in the pocket 31 and in turn apply a second lifting force F2 to the foundation which can raise the section of foundation to the required height in a second lifting step, i.e., level "C" in figures 2, 3 and 5.

[0102] A second controller 25 can control the second lifting step by either one or a combination of: i) adjusting the pressure of the concrete in the pocket 31, adjusting the flow rate of the concrete in the conduit 24 by adjusting the pump 22 (or valve 23) ; and iii) adjusting the volume of the concrete delivered to the pocket 31.

[0103] Figure 4 is an illustration of a section of foundation 10 in the form of a corner trench foundation having a brick veneer wall or a solid brick wall 20 on top of the foundation 10.

[0104] Figure 5 is a cross-sectional view of a section of foundation 10 in the form of a concrete slab. As can be seen, a peripheral region of the concrete slab has subsided to level "A" and an outer region adjacent to the peripheral region has also subsided. The pocket 31 formed by the first lifting step may be formed under the peripheral region and possibly also under the outer region adjacent to the peripheral region.

[0105] Those skilled in the present invention will appreciate that many variations and modifications can be made to the preferred embodiment without departing from the spirit and scope of the present invention.

Reference Numeral Table

section of the foundation 10 wall of the building 20 first lift assembly 11 reservoir of flowable material 21 lifting bar 12 second pump 22 lifting bracket 13 Valve 23 lifting points 14 conduit 24 lifting jacks 15 second controller 25 stop member 16 pressure sensor 26 first pump 17 flow rate monitor 27 first controller 18 volume monitor 28 source of hydraulic fluid 19 Earth 29 first line 30 Pocket 31 subsided level A first lifted position B second lifted position C

Claims (28)

1. A method of raising a foundation of a building, the method includes the steps of:

a first lifting step of lifting a section of foundation of the building, wherein the first lifting step includes operating an actuator to apply a first lifting force that lifts the section of foundation to a first lifted position; and

a second lifting step of lifting the section of foundation from the first lifted position to a second lifted position that is higher than the first lifted position, wherein the second lifting step includes injecting flowable material under the section of the foundation which raises the section of the foundation of the building.

2. The method according to claim 1, wherein the first lifting step forms a pocket between the section of foundation and a bed on which the foundation sits.

3. The method according to claim 2, wherein the second lifting step includes injecting the flowable material into the pocket and allowing the flowable material to harden which underpins the section of the foundation.

4. The method according to any one of the preceding claims, wherein the second lifting step includes injecting the flowable material into the pocket until the section of foundation has been lifted to the second lifted position.

5. The method according to any one of the preceding claims, wherein the second lifting step includes controlling the pressure of the flowable material injected under the foundation to control the second lifted position.

6. The method according to any one of the preceding claims, wherein the first lifting step includes applying a first lifting force to multiple lift points to the section of foundation.

7. The method according to claim 6, wherein the lift points are spaced in the range of 150mm to 1000mm apart, suitably in the range of 250 to 700mm apart, ideally in the range of 300 to 500mm apart, and even more ideally approximately 400mm apart.

8. The method according to claim 6 or 7, wherein the first lifting force applied at each lifting point is up to 15 tonne, and suitably in the range of 6 to 10 tonne, and ideally approximately 8 tonne.

9. The method according to any one of claims 6 to 8, wherein the first lifting step includes controlling a first lifting force applied to the section of foundation at each of the lifting points.

10. The method according to claim 9, wherein controlling the first lifting force includes applying the same lifting force at the or each of the lifting points.

11. The method according to claim 8 or 9, wherein controlling the first lifting force includes adjusting the lifting force at the or each lifting point individually.

12. The method according to any one of claims 8 to 10, wherein controlling the first lifting force includes operating the actuator that applies the first lifting force at the or each lifting point.

13. The method according to claim 12, wherein the first lifting step includes fitting anchors to the foundation at spacings along the foundation at each lifting point.

14. The method according to any one of the preceding claims, wherein the second lifting step includes lifting the section of foundation to a height that restores the height the section of foundation relative to the adjacent segments of the foundation.

15. The method according to any one of the preceding claims, wherein the second lifting step includes controlling a second lifting force applied to the section of foundation.

16. The method according to any one of the preceding claims, wherein the second lifting force can be up to 15 tonne per lineal metre, and suitably in the range of 6 to tonne lineal metre, and ideally approximately 8 tonne per lineal metre of the section of foundation.

17. The method according to any one of the preceding claims, wherein the second lifting step includes pressurising the flowable material that is injected and controlling the pressure of the flowable material to control the height of the second lifted position.

18. The method according to any one of the preceding claims, wherein the second lifting step includes controlling the pressure in the flowable material to a pressure up to 300 psi.

19. The method according to claim 17, wherein the second lifting step includes operating a pump that pumps the flowable material and/or a valve that regulates the flow of the flowable material, and in turn, controls the pressure of the flowable material.

20. The method according to any one of the preceding claims, wherein the method includes determining the height of the second lifted position, and monitoring the height of the section of foundation during the second lifting step and stopping the second lifting step when the section of foundation has reached the second lifted position.

21. An apparatus for raising a foundation of a building, the apparatus includes:

a first lift assembly including at least one actuator that is operable to apply a first lifting force that can lift a section of foundation of the building toa first lifted position; and

a second lift assembly that is operable to apply a second lifting force that can lift the section of foundation from the first lifted position to a second lifted position that is higher than the first lifted position, wherein the second lifting assembly includes an injector that injects a flowable material under the section of the foundation which raises the section of the foundation to the second lifted position.

22. The apparatus according to claim 20, wherein the first lifting assembly can form a pocket between the section of foundation and a bed on which the foundation sits at a first lifted position, and the flowable material can harden after being injected into the pocket and thereby underpin the section of foundation of the building.

23. The apparatus according to claim 21 or 22, wherein the second lifting assembly pressurises the flowable material that is injected under the foundation to apply the second lifting force.

24. The apparatus according to any one of claims 21 to 23, wherein the second lifting assembly includes a controller that controls pressurisation of the flowable material and thereby controls the height of the second lifted position.

25. The apparatus according to any one of claims 21 to 24, wherein the second lift assembly includes a reservoir of the flowable material, a pump that receives the flowable material from the reservoir, and a conduit for conveying the flowable material from the pump, the conduit has an opening that, when in use, supplies the flowable material under the foundation.

26. The apparatus according to any one of claims 21 to 25, wherein the second lift assembly includes a plurality of the conduits for supplying the flowable material at internals along the section of foundation.

27. The apparatus according to any one of claims 21 to 26, wherein the second lifting assembly includes a controller that is operable to do allow one or more of the following: i) adjust the pressure of the flowable material discharged from the pump, and thus adjust the pressure of the flowable material supplied by the conduit into the pocket. ii) adjust the flowrate of the flowable material discharged from the conduit. iii) measure the volume of the flowable material discharged from the conduit. For example, by adjusting a valve that in the conduit. iv) turn the pump ON and/or OFF.

28. The apparatus according to any one of claims 1 to 27, wherein the first lift assembly includes multiple lifting points spaced along the length of the section of the foundation, and the at least one actuator is operable to apply the first lifting forces to the lifting points, wherein the first lifting forces applied at the lifting points can be individually adjusted.