Grout tube system for precast wall panel installation

Abstract

A grout tube system for precast wall panel installation is disclosed, comprising a tubular section, a flared base at one end, and an inlet section at the other. The grout tube is cast into the wall panel to guide starter bars from a floor slab into the tube during installation. The flared base defines a funnel-shaped opening to accommodate misalignment, enhancing safety and installation efficiency. Grout is injected via the inlet section to encapsulate the starter bars, securing the panel to the slab. The funnel may have an elongate cross-section, and the inlet rim lies flush with formwork to prevent concrete ingress.

Description

Grout Tube System for Precast Wall Panel InstallationField of the Invention

[0001] This invention relates generally to construction components for precast concrete structures. More particularly, the invention relates to grout tube systems for use in tilt-up or precast panel installation, to facilitate alignment with starter bars and secure structural interconnection with a floor slab.Background of the Invention

[0002] A grout tube is a component designed for use in precast concrete construction. These tubes are hollow and can be made from plastic or thin sheet metals. They are cast into precast elements to create voids for locating and connecting these elements with starter or dowel bars. After placement, grout tubes are filled with grouting material to lock the elements in position, enhancing the strength and durability of the construction.

[0003] In the use of grout tubes for tilt-up precast panels, the tubular sections are strategically precast within the panels and numbered to align with corresponding starter or dowel bars for precise connection. These elements are spaced accurately to ensure that, once the panel is hoisted into place by a crane, each grout tube aligns with its respective starter or dowel bar. This method ensures structural integrity and simplifies the process of aligning and securing the panels to the foundation or to each other.

[0004] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.Summary of the Disclosure

[0005] The present disclosure relates to a system for aligning and securing precast wall panels to a floor slab using grout tubes. The system is particularly advantageous in tilt-up panel construction, where precise placement of panels over embedded starter bars is critical for structural integrity and safety.

[0006] The system comprises a grout tube embedded in a precast wall panel that is installed perpendicularly on a floor slab. The grout tube comprises a tubular section, a flared base at a first end of the tubular section, and an inlet section at a second, opposite end. The flared base defines a funnel-shaped opening leading into the tubular section. The grout tube is precast into the wall panel during horizontal formation, such that, upon erection of the panel, the funnel-shaped opening is presented at the base of the panel for receiving starter bars embedded in the floor slab. The starter bars may be spaced in correspondence with the spacing of the grout tubes.

[0007] Upon installation, the panel is hoisted over the starter bars, which are received into the tubular sections via the funnel-shaped openings. This geometry avoids the need for precise coaxial alignment and enables the wall panel to be lowered into place without visual inspection from underneath. The inlet sections of the grout tubes define openings for grout injection. Grout is introduced through these inlets to fill the tubes from the bottom up, encapsulating the starter bars and thereby securing the wall panel to the floor slab.

[0008] In a preferred embodiment, the flared base defines a funnel-shaped opening having an elongate cross-section defining a longitudinal axis and a transverse axis, and wherein the inlet section is aligned along the transverse axis. This arrangement maximises the cross-sectional area of the funnel-shaped opening within the limited transverse dimension of the wall panel, thereby improving tolerance for longitudinal misalignment between the wall panel and the row of starter bars embedded in the floor slab. As a result, the installer is afforded greater margin for positioning error along the length of the panel, facilitating faster and safer alignment without requiring precise coaxial placement. Additionally, this configuration increases the interior volume of the flared base at the critical panel-to-slab interface, enhancing the quantity of grout in this region and thereby improving mechanical interlock and structural strength, particularly at the lowermost point where bending and shear forces are most significant.

[0009] Preferably, the tubular section is cylindrical, which advantageously resists bending stresses from all directions and enhances load distribution through the grout.

[0010] In further preferred embodiments, the tubular section defines a smooth internal bore, facilitating smooth insertion of starter bars and preventing snagging during placement.

[0011] In some embodiments, the flared base defines a rectangular entrance. The rectangular entrance may taper to a circular cross-section at the tubular section, optimising the grout volume at the base of the panel and improving interlock with the slab and providing a smooth interface transitioning into the tubular section.

[0012] In embodiments, the inlet section defines a rim that is coplanar with a plane intersected perpendicularly by the transverse axis and parallel to the longitudinal axis. This configuration enables the rim to lie flat on a horizontal formwork surface, thereby forming a concrete-resistant seal during panel casting.

[0013] In a preferred form, the inlet section defines a coaxial axis perpendicular to both the longitudinal axis of the flared base and the longitudinal axis of the tubular section. This perpendicular orientation reduces the length of the inlet section required to reach the surface of the wall panel and allows the inlet opening to remain flush with the panel surface.

[0014] In certain embodiments, the system includes formwork comprising a base formwork panel and side panels, wherein the grout tube is installed with the tubular section parallel to the surface of the base panel, and the rim of the inlet section lies flat against the base panel. This orientation prevents concrete ingress into the tube during casting.

[0015] The flared base may further define a long edge parallel to the longitudinal axis, with the inlet section extending beyond the long edge. This allows the flared base to be centrally located in the wall panel, with the inlet extending to the edge of the panel.

[0016] In a particularly preferred embodiment, the inlet section extends from the central axis of the tubular section exactly half the width of the wall panel, so that the inlet opening reaches the surface of the wall panel without protrusion.

[0017] The inlet section may be integrally formed with the tubular section and fixed in orientation, simplifying installation and ensuring a rigid geometry during panel fabrication.

[0018] In some embodiments, the inlet section has a cross-sectional area that matches the cross-sectional area of the tubular section, allowing for unobstructed grout flow and reliable filling of the tube.

[0019] Preferably, the flared base defines a peripheral flange, which may include fixation apertures for securing the grout tube to formwork prior to casting. In certain embodiments, the grout tube may be affixed perpendicularly from a formwork panel by way of these fixation apertures, thereby maintaining precise positioning during casting.

[0020] The system may further include side brace flanges that extend between the peripheral flange and the sides of the flared base. These brace flanges may extend to the exterior sides of the tubular section, providing additional rigidity and bending resistance. These side brace flanges may define edge recesses, enabling reinforcement bar to be positioned closer to the flared base while maintaining clearance from the concrete panel surfaces.

[0021] The exterior of the tubular section may define spaced-apart rib sets, which may include reinforcing ribs to promote mechanical keying with the surrounding concrete. Smooth sections may be formed between the rib sets to simplify manufacture. These rib sets may also include recesses aligned with the transverse axis, which assist in locating and holding reinforcement bar in place during casting.

[0022] In preferred embodiments, the grout tube is formed entirely of plastic, which may be moulded in a single monolithic piece. Alternatively, the tubular section may comprise bifurcated interconnecting portions, such as male and female connectors, that form a contiguous smooth bore when connected and which allow for additional tubular sections to be installed therebetween to extend the length of the tubular section.

[0023] These connectors may include rotational keying to ensure that the inlet section remains aligned along the transverse axis, maintaining consistent geometry across multiple grout tubes.

[0024] The present disclosure also provides a method of installing a precast wall panel using the above system. The method comprises positioning the wall panel above a floor slab having protruding starter bars, lowering the wall panel such that the starter bars are received into the tubular sections of the grout tubes via the funnel- shaped openings, and injecting grout into the inlet sections to fill the grout tubes and encapsulate the starter bars. In a preferred form of the method, the rim of the inlet section lies flat on a base formwork panel during the casting of the wall panel, preventing concrete from entering the grout tube and simplifying post-cure preparation.

[0025] Other aspects of the invention are also disclosed.Brief Description of the Drawings

[0026] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0027] Figure 1 shows a cross-sectional view of a grout tube system for precast wall panel installation;

[0028] Figure 2 shows a top perspective view of a grout tube of the system in accordance with a preferred embodiment;

[0029] Figure 3 shows a bottom perspective view of the grout tube to be:

[0030] Figure 4 shows a side elevation view of the grout tube;

[0031] Figure 5 shows a front elevation view of the grout tube; excellent Figure 6 shows a bottom plan view of the grout tube; and

[0032] Figure 7 shows a top view of the grout tube.Description of Embodiments

[0033] Figure 1 shows a cross-sectional view of a system 101 comprising a grout tube 102 embedded in a precast wall panel 103, which is installed perpendicularly on afloor slab 104. With reference to Figures 2 to 7, the grout tube 102 defines a tubular section 105, a flared base 106 at a first end of the tubular section 105, and an inlet section 107 at a second, opposite end of the tubular section 105.

[0034] The flared base 106 defines a funnel-shaped opening leading into the tubular section 105. As shown in Figure 2, the grout tube 102 is precast into the wall panel 103 while the panel is formed horizontally. Once set, the flared base 106 defines the funnel-shaped opening 109 at the base of the wall panel 103. Typically, multiple grout tubes 102 are spaced along the length of the wall panel 103 at predetermined intervals, such as at 1 m centres.

[0035] The floor slab 104 is cast with a row of embedded starter bars 108 protruding from its upper surface. The starter bars 108 may be spaced to match the spacing of the grout tubes 102.

[0036] The wall panel 103 is then hoisted into place over the starter bars 108 using a crane or similar equipment. The funnel-shaped openings 109 guide the ends of the starter bars 108 smoothly into the tubular sections 105 without requiring precise coaxial alignment, allowing easier and safer installation. This avoids the need to visually inspect the alignment from beneath the panel, which is often hazardous. The funnel-shaped openings may also accommodate minor misalignment or bending of the starter bars 108.

[0037] The inlet sections 107 define openings through which grout is injected, thereby filling the interior of the grout tubes 102 from the bottom up. Once set, the grout encapsulates the starter bars 108 and secures the wall panel 103 to the floor slab 104.

[0038] In a preferred embodiment, shown in Figure 6, the funnel-shaped opening 109 has an elongate cross-section that defines a longitudinal axis 1 10 and a transverse axis 111. The inlet section 107 is aligned with the transverse axis 1 11. This arrangement maximises the funnel-shaped opening 109 across the limited transverse width of the wall panel 103, thereby accommodating longitudinal misalignment of the wall panel 103 relative to the row of starter bars 108. It also increases the volume of grout at the interface between the wall panel 103 and floor slab 104, therebyimproving the structural connection at the lowermost point where bending forces are greatest.

[0039] In a preferred embodiment, the tubular section 105 is cylindrical to provide uniform resistance to bending forces in all directions. The tubular section 105 preferably has a smooth internal bore, free from snag points that might catch on the tips of the starter bars 108.

[0040] Referring to Figure 6, the flared base 106 preferably defines a rectangular entrance 1 12, which provides a greater cross-sectional area than other elongate or oblong configurations such as ovals. The flared base 106 may taper from the rectangular entrance 1 12 to a circular cross-section at the tubular section 105. In the embodiment shown, the flared base 106 is somewhat frustopyramidal, with long side walls and short end walls with rounded corners, which converge to the circular crosssection at the tubular section 105.

[0041] With reference to Figures 4 and 5, the inlet section 107 may define a coaxial axis 113 that is perpendicular to both the longitudinal axis 110 of the flared base 106 and a longitudinal axis 1 14 of the tubular section 105. That is, the inlet section 107 may be orthogonal to the tubular section 105. This orientation minimises the required length of the inlet section 107 to reach the surface of the wall panel 103, minimises the cross-sectional area of the opening (as compared to an angled opening), and provides a rim that may be coplanar with the surface of the wall panel 103, thereby reducing or eliminating the need for post-installation trimming.

[0042] Further, with reference to Figures 6 and 7, the inlet section 107 preferably defines a rim 1 19 that is coplanar with a plane 128, which is perpendicular to the transverse axis 1 11 and parallel with the longitudinal axis 1 10 of the flared base 106. This allows the rim 119 to lie flat on a horizontal formwork panel during casting. Specifically, during formation of the wall panel 103, the formwork may comprise a horizontal base panel and vertical side panels into which concrete is poured to encapsulate the grout tube 102. The grout tube 102 is installed with the tubular section 105 parallel to the base panel and the rim 1 19 of the inlet section 107 lyingflat on its upper surface. This prevents ingress of concrete into the inlet section 107 during casting.

[0043] As shown in Figures 6 and 7, the flared base 106 may define a long edge 1 15 parallel to the longitudinal axis 1 10, and the inlet section 107 may extend beyond this long edge 1 15. This enables the flared base 106 to be centrally positioned within the width of the wall panel 103 (as shown in Figure 1 ), with the rim of the inlet section 107 reaching the adjacent surface of the wall panel 103.

[0044] Preferably, the length of the inlet section 107 is configured to match the width of the wall panel 103 so that its rim lies flush with the surface of the wall panel 103 when the flared base 106 is centrally located. In this respect, the width of the flared base 106 may be narrower than the width of the wall panel 103, with the inlet section 107 extending from a central axis 1 16 of the tubular section 105 by half the wall panel's width.

[0045] The inlet section 107 is preferably integrally formed with the tubular section 105 and fixed in orientation, such that it is not adjustable or bendable relative to the tubular section 105. This enables the system to be installed orthogonally, as illustrated in Figure 1 , without needing to reposition or realign the inlet section 107.

[0046] The cross-sectional area of the inlet section 107 preferably matches that of the tubular section 105, ensuring an unconstricted passage for grout and for displacement of air and water during grouting.

[0047] The flared base 106 preferably defines a peripheral flange 1 17, which may include fixation apertures 1 18 at its corners. During horizontal casting of the wall panel 103, the grout tube 102 may be affixed perpendicularly to a vertical side formwork panel using these apertures. As noted above, the inlet section 107 lies flat on the base formwork panel. After concrete is poured and has set, the formwork panels are removed, leaving the funnel-shaped opening at the position of the vertical formwork panel and the inlet opening at the position of the horizontal formwork panel. The rim 1 19 seals against the base panel, preventing concrete ingress and minimising the need to expose the inlet after curing.

[0048] The grout tube 102 may include side brace flanges 120 aligned with the transverse axis 1 1 1 and extending between the peripheral flange 1 17 and the sides of the flared base 106. These flanges 120 may extend to the sides of the tubular section 105 to provide additional reinforcement against bending. The brace flanges 120 resist transverse deformation of the flared base 106, while the elongate shape of the flared base inherently resists longitudinal deformation.

[0049] The side brace flanges 120 may also define edge recesses 126 that allow transverse reinforcement bars to be positioned close to the sides of the flared base 106 and away from the outer surfaces of the wall panel 103. These recesses may assist in locating reinforcement bars before concrete is poured.

[0050] As shown in Figure 5, the exterior of the tubular section 105 may include spaced-apart rib sets 122 comprising a series of ribs 123 to reinforce the tubular section 105 and provide mechanical keying into the surrounding concrete. The rib sets 122 may be separated by smooth sections 124, which simplify the manufacturing process. The rib sets may further define recesses 127 aligned with the transverse axis 1 1 1 to position and retain reinforcement bars close to the sides of the tubular section 105 prior to pouring.

[0051] The grout tube 102 is preferably made entirely from plastic, such as by injection moulding. In one embodiment, the grout tube 102 is formed monolithically as a single piece.

[0052] However, as shown in Figure 4, the tubular section 105 may be formed from bifurcated interconnecting portions 121 . These portions 121 may include male and female connectors 125 that engage with each other while maintaining a smooth interior bore. These connectors 125 may include rotational keying features such as slots or tabs to preserve alignment of the inlet section 107 along the transverse axis 1 1 1. The grout tube 102 may comprise additional extension tubular sections (not shown) which can be fitted between the portions 121 to extend the overall length of the tubular section 105. These extension tubular sections may comprise conforming connectors 125 which seamlessly connect with those of the bifurcated sections 121.

[0053] An example method of use of the system 101 will now be described. Initially, a formwork assembly is prepared comprising a horizontal base formwork panel and a plurality of vertical side formwork panels arranged around the periphery of the base panel to define the intended shape of the wall panel 103. The grout tube 102 is installed into the formwork prior to pouring, such that the tubular section 105 lies horizontally along the upper surface of the base formwork panel and the inlet section 107 lies flat on that surface. The flared base 106 is affixed perpendicularly to an interior face of one of the side formwork panels by way of the fixation apertures 1 18 formed in the peripheral flange 1 17.

[0054] During installation, the rim 1 19 of the inlet section 107 is pressed flush against the upper surface of the base formwork panel so as to create a seal that resists ingress of concrete during pouring. The flared base 106 is thereby oriented orthogonally relative to the inlet section 107 and tubular section 105, and the grout tube 102 as a whole is fixed in its intended orientation, ready for embedding.

[0055] Concrete is then poured into the formwork assembly, flowing around the grout tube 102 and encapsulating the tubular section 105, the flared base 106, and the inlet section 107 without entering the internal bore of the grout tube 102 due to the rim 1 19 lying flush against the base formwork panel. The peripheral flange 1 17, along with the side brace flanges 120, ensures that the grout tube 102 remains stable and properly aligned during the pour.

[0056] Once the concrete has cured, the formwork panels are stripped. The removal of the side formwork panel to which the flared base 106 was affixed reveals the funnel-shaped opening 109 at the base of the now-hardened wall panel 103. Similarly, the removal of the base formwork panel reveals the inlet section 107 at the rear face of the wall panel 103, with the rim 1 19 of the inlet section 107 having prevented concrete ingress into the grout tube 102.

[0057] Separately, the floor slab 104 is cast with a row of starter bars 108 embedded therein and protruding vertically from its upper surface. The spacing of the starter bars 108 corresponds to the spacing of the grout tubes 102 within the wall panel 103, such that alignment during installation is facilitated.

[0058] The wall panel 103 is then hoisted using a crane or lifting rig and positioned onto the floor slab 104 such that the protruding starter bars 108 are received within the grout tubes 102. The funnel-shaped openings 109 of the flared bases 106 assist in guiding the starter bars 108 into the tubular sections 105, even if the starter bars 108 are slightly out of alignment. This reduces the need for precision placement and avoids the need to manually inspect alignment beneath the panel, which may present safety risks.

[0059] With the wall panel 103 in position and the starter bars 108 received within the grout tubes 102, grout is poured into the inlet sections 107. The grout flows through the tubular sections 105 and fills the space around the starter bars 108, ultimately filling the interior volume defined by the flared bases 106. This process ensures full encapsulation of the starter bars 108 and promotes a strong mechanical interlock between the wall panel 103 and floor slab 104.

[0060] The preferable rectangular entrance 1 12 defined by the flared base 106 maximises the grout volume at the interface between the panel and slab, and the enlarged funnel shape ensures that any air or residual water within the grout tube 102 is displaced as grout is introduced. The matched cross-sectional areas of the inlet sections 107 and tubular sections 105 avoid constriction and enable consistent grout flow.

[0061] Once the grout has set, the starter bars 108 are fixed within the wall panel 103 by way of the keyed grout column, completing the structural integration of the wall panel 103 with the floor slab 104. The interlocking geometry of the flared base 106, including its preferable elongate and frustopyramidal shape, enhances the interface strength, particularly at the lowermost point where shear and bending forces are most concentrated. The optional rib sets 122 on the exterior of the tubular section 105 further assist in mechanical keying with the surrounding concrete, and the side brace flanges 120 provide transverse stability throughout the panel’s service life.

[0062] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order topractise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

Claims

Claims1 . A system comprising a grout tube having a tubular section, a flared base at a first end of the tubular section, and an inlet section at a second, opposite end of the tubular section, wherein the flared base defines a funnel-shaped opening leading into the tubular section, the funnel-shaped opening having an elongate cross-section that defines a longitudinal axis and a transverse axis, and wherein the inlet section is orientated along the transverse axis.

2. The system of claim 1 , wherein the tubular section is cylindrical.

3. The system of claim 2, wherein the tubular section defines a smooth internal bore.

4. The system of claim 1 , wherein the flared base defines a rectangular entrance.

5. The system of claim 4, wherein the flared base funnels from the rectangular entrance to a circular cross-section at the tubular section.

6. The system of claim 1 , wherein the inlet section defines a rim being coplanar with a plane intersected perpendicularly by the transverse axis and parallel with the longitudinal axis.

7. The system of claim 1 , wherein a coaxial axis defined by the inlet section is perpendicular to both the longitudinal axis and a longitudinal axis defined by the tubular section.

8. The system of claim 6, further comprising formwork including a base formwork panel and side formwork panels, wherein the grout tube is installed with the tubular section parallel with a surface of the base formwork panel and the rim lying flat on the surface of the base formwork panel.

9. The system of claim 1 , wherein the flared base defines a long edge parallel with the longitudinal axis, and wherein the inlet section extends beyond the long edge.

10. The system of claim 9, further comprising a wall panel, wherein the flared base is centrally located across the width of the wall panel, wherein a width of the flared base is less than the width of the wall panel, and wherein the inlet section extends from a central axis defined by the tubular section at least half the width of the wall panel.1 1 . The system of claim 10, wherein the inlet section extends from the central axis defined by the tubular section exactly half the width of the wall panel.

12. The system of claim 1 , wherein the inlet section is integrally formed with the tubular section and maintains a fixed orientation relative to the tubular section.

13. The system of claim 1 , wherein a cross-sectional area of the inlet section matches a cross-sectional area of the tubular section.

14. The system of claim 1 , wherein the flared base defines a peripheral flange.

15. The system of claim 14, wherein the peripheral flange defines fixation apertures.

16. The system of claim 15, further comprising a formwork panel, wherein the grout tube is affixed perpendicularly from the formwork panel by the fixation apertures.

17. The system of claim 14, further comprising side brace flanges coplanar with the transverse axis and extending between the peripheral flange and sides of the flared base.

18. The system of claim 17, wherein the side brace flanges extend beyond the flared base to exterior sides of the tubular section.

19. The system of claim 17, wherein the side brace flanges define edge recesses.

20. The system of claim 1 , wherein an exterior of the tubular section defines spaced apart rib sets.21 . The system of claim 20, wherein the exterior of the tubular section defines smooth sections between the spaced apart rib sets.

22. The system of claim 20, wherein the rib sets define recesses orientated along the transverse axis.

23. The system of claim 1 , wherein the grout tube is made entirely of plastic.

24. The system of claim 23, wherein the grout tube is monolithically formed as one piece of plastic.

25. The system of claim 1 , wherein the tubular section comprises interconnecting portions.

26. The system of claim 25, wherein the interconnecting portions define male and female insertion connectors.

27. The system of claim 26, wherein the connectors comprise rotational keying to align the inlet section along the transverse axis.

28. A method of installing a precast wall panel using the system of claim 1 , the method comprising: positioning the precast wall panel above a floor slab having a row of protruding starter bars; andlowering the wall panel such that the starter bars insert into the tubular sections of respective grout tubes via the funnel-shaped openings defined by the flared bases; and injecting grout into the inlet sections to fill the grout tubes from the bottom up and encapsulate the starter bars within the tubular sections.

29. The method of claim 28, wherein the inlet section defines a rim being coplanar with a plane intersected perpendicularly by the transverse axis and parallel with the longitudinal axis and wherein the rim is laid flat on a surface of a base formwork panel during casting of the wall panel.

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