Related Applications

[0001] This application claims the benefit of the priority of US application No. 61/654024 filed 31 May 2012 which is hereby incorporated herein by reference.

Technical Field

[0002] This invention relates to repairing or otherwise lining existing structures using lining structures fabricated from concrete and/or similar curable materials and formed in structure- lining apparatus. In particular, this invention relates to rebar adapters for supporting rebar in structure-lining apparatus used to fabricate lining structure which in turn line existing structures.

Background

[0003] Concrete is used to construct a variety of structures, such as building walls and floors, bridge supports, dams, columns, raised platforms and the like. Typically, concrete structures are formed using embedded reinforcement bars (often referred to as rebar) or similar steel reinforcement material, which provides the resultant structure with increased strength. It is known to provide repair structures (or other lining structures) which may be fabricated from concrete or other curable materials and may be used to repair or otherwise line existing structures. Lining structures may be fabricated using structure-lining apparatus in which the concrete or other curable material may be introduced and permitted to cure to provide the resultant lining structure which lines the existing structure. Examples of structure- lining apparatus and associated lining structures are disclosed in the patent application published as WO2010/078645. A class of structure-lining apparatus, referred to as stay-in-place structure lining apparatus, are at least partially embedded in the lining structure as the lining structure cures, so that the structure- lining apparatus remains in place after curing as part of the resultant lining structure.

[0004] Lining structures represent one type of structure. Stay-in-place structure-lining apparatus may also be used to provide linings on other types of structures or portions thereof. Examples of structure-lining apparatus used to line other types of structures are disclosed in the patent application published as WO2008/119178.

[0005] Some structure-lining apparatus use standoffs to separate a lining surface from a portion of the existing structure to be lined. Some structure-lining apparatus use standoffs for other additional or alternative purposes, such as to connect components of the lining surface, to locate the lining surface, to anchor the lining surface to the resultant structure fabricated using the structure-lining apparatus and/or to locate rebar within the structure-lining apparatus during fabrication. In some structure-lining apparatus, rebar members extend through apertures in standoffs and are also rigidly anchored to other structural components, such to an existing structure, to a structural formwork, to other rebar and/or the like. In these situations, when concrete is introduced into the structure-lining apparatus, the expansive force caused by the weight of the liquid concrete may result in force between the rebar and the standoffs which may damage the standoffs.

[0006] Figures 1 A and IB (together, Figure 1) respectively show a partial plan view and a cross- sectional view (along line IB- IB) of a portion of an example prior art structure-lining apparatus 10 having standoffs 12 and a lining surface 13. Lining surface 13 extends in transverse directions indicated by double-headed arrow 30 and in longitudinal directions indicated by double-headed arrow 32. Standoffs 12 are connected to lining surface 13 at connections 22 and extend in an inward direction (indicated by arrow 36) from lining surface 13 toward existing structure 15. Rebar member 14 extends in transverse direction 30 through apertures 12A in standoffs 12 and is rigidly anchored to existing structure 15 by rebar anchors 16. In the Figure 1 example structure- lining apparatus 10, rebar anchors 16 comprise J-bolts 16 A. Rebar anchors 16 are rigidly anchored to existing structure 15 and comprise rebar receivers 16B (e.g. the hook portions of J- bolts 16A). Rebar receivers 16B receive rebar members 14 and are shaped to prevent rebar members 14 from moving in an outward direction (indicated by arrow 34) away from existing structure 15. [0007] Liquid concrete 17, or other curable material, is introduced into space 17A between lining surface 13 and existing structure 15. Prior to curing, concrete 17 exerts force (shown by arrows 18) against lining surface 13 in outward direction 34. As shown in Figure IB, this outwardly directed force causes lining surface 13 and standoffs 12 (which are coupled to lining surface 13 at connections 22) to be forced in the outward direction 34. However, rebar member 14 experiences relatively little force in outward direction 34 (because of its relatively small surface area) and, as discussed above, rebar member 14 is prevented from outward movement by rebar anchors 16, which are rigidly anchored to existing structure 15. As a result, rebar member 14 exerts considerable force against standoffs 12 at the inward edges of apertures 12A and standoff 12 may be damaged and/or plastically deformed by rebar member 14. Rebar member 14 may even tear through standoffs 12 and become disconnected from structure-lining apparatus 10. When standoffs 12 are damaged or deformed, the resultant structure fabricated using structure- lining apparatus 10 may have non-uniform (e.g. uneven) surfaces and/or weakened structural integrity.

[0008] There is a general desire for improved structure-lining apparatus and improved methods for use of same. There is a general desire for improved coupling between standoffs and rebar members of structure-lining apparatus.

[0009] The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

Summary

[0010] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.

[0011] One aspect of the invention provides a stay-in-place structure-lining apparatus used to fabricate a lining structure which lines an existing structure using concrete or other curable material. The structure-lining apparatus comprises: a plurality of rebar members, each rebar member extendable in a transverse direction; a plurality of rebar anchors rigidly anchorable to the existing structure, each rebar anchor comprising a rebar receiver shaped to receive an associated one of the rebar members and shaped to prevent movement of the associated one of the rebar members in an outward direction away from the existing structure when the rebar anchor is anchored to the existing structure and the associated one of the rebar members is received in the rebar receiver; a lining surface shaped to be extendable in the transverse direction and in a longitudinal direction; a plurality of standoffs coupleable to the lining surface and, when so coupled, shaped to extend in the longitudinal direction and also in an inward direction away from the lining surface and toward the existing structure, each of the standoffs apertured to permit transverse extension of one or more of the rebar members therethrough; and one or more rebar adapters for coupling the rebar members to the standoffs at locations where the rebar members extend through the apertures of the standoffs, each rebar adapter comprising: a standoff connector shaped to be coupleable to a corresponding one of the standoffs; and a rebar support shaped to be coupleable to a corresponding one of the rebar members at a location where the corresponding one of the rebar members extends through an aperture of the corresponding one of the standoffs.

[0012] Another aspect of the invention provides a method for fabricating a lining structure which lines an existing structure using concrete or other curable material, the method comprising: connecting a structure-lining apparatus to the existing structure, wherein connecting the structure-lining apparatus to the existing structure comprises: anchoring a plurality of rebar anchors to the existing structure, the anchored rebar anchors extending in an outward direction away from the existing structure to provide rebar receivers at locations spaced outwardly apart from the existing structure; connecting a plurality of rebar members to the rebar receivers of the rebar anchors, each connected rebar member extending in a transverse direction between the rebar receivers of two or more of the rebar anchors and each connected rebar member prevented from outward movement away from the existing structure by the rebar receivers of the two or more of the rebar anchors; providing a lining surface shaped to extend in the transverse direction and in a longitudinal direction at a location outward from the rebar receivers; coupling a plurality of standoffs to the lining surface to extend in the longitudinal direction and also in an inward direction away from the lining surface and toward the existing structure; extending the rebar members in the transverse direction through apertures in the standoffs; and at each location where one of the rebar members extends in the transverse direction through one of the apertures in one of the standoffs: providing a rebar adapter comprising a standoff connector and a rebar support; coupling the standoff connector to the one of the standoffs; and coupling the rebar support to the one of the rebar members. The method also comprises introducing concrete or other curable material to a space between the existing structure and the lining surface.

[0013] Another aspect of the invention provides a rebar adapter for coupling rebar to a stay-in- place structure-lining apparatus used to line an existing structure with a lining structure fabricated from concrete or other curable material, the structure-lining apparatus comprising a lining surface that extends in longitudinal and transverse directions and one or more

longitudinally extending standoffs that also extend in an inward direction away from the lining surface, the rebar adapter comprising: a transversely extending and outwardly opening rebar support shaped to be coupleable to a transversely extending rebar member by moving the rebar support in the outward direction relative to the rebar member; and a longitudinally extending and inwardly opening standoff connector dimensioned to fit within an aperture of a corresponding one of the one or more standoffs and shaped to be coupleable to the corresponding one of the one or more standoffs by moving the standoff connector in the inward direction relative to the standoff; wherein the longitudinal, transverse and inward directions are at least approximately mutually orthogonal to one another.

[0014] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.

Brief Description of the Drawings

[0015] Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

[0016] Figure 1 A is a partial plan view of a prior art structure-lining apparatus.

[0017] Figure IB is a partial cross-sectional view (along line IB- IB) of the Figure 1 A structure- lining apparatus showing damage to the structure-lining apparatus.

[0018] Figure 2 is a perspective view of a portion of a structure-lining apparatus incorporating rebar adapters according to an example embodiment.

[0019] Figures 3A-3C (together Figure 3) are perspective, front elevation, and side elevation views respectively of a rebar adapter used in the Figure 2 structure- lining apparatus.

[0020] Figures 4A-4D are various views of steps involved in coupling a standoff and rebar adapter of the Figure 2 structure- lining apparatus.

[0021] Figures 5 A-5D are schematic views of various standoff heads according to example embodiments.

[0022] Figures 6A-6D are schematic views of various rebar adapter standoff connectors according to example embodiments.

[0023] Figures 7A, 7B and 7C are schematic views of various rebar adapters and standoffs according to other example embodiments.

[0024] Figure 8A is a perspective view of a rebar adapter coupled to a pair of rebar members according to another example embodiment. Figures 8B-8D are a perspective view, a front elevation view and a side elevation view respectively of the Figure 8A rebar adapter in isolation. [0025] Figure 9 is a partial plan view of a structure-lining apparatus according to another example embodiment.

[0026] Figure 10 is a partial plan view of a structure-lining apparatus according to another example embodiment.

[0027] Figure 11 is a partial plan view of a structure-lining apparatus according to another example embodiment.

Description

[0028] Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

[0029] Aspects of the invention provide rebar adapters for use in structure-lining apparatus which are in turn used for fabricating structures (e.g. lining structures which line existing structures and/or structures generally) made of concrete and/or other curable materials. Aspects of the invention provide structure- lining apparatus incorporating such rebar adapters and methods for use of same. In particular embodiments, rebar adapters are coupled to rebar members and to standoffs to provide interfaces therebetween. Without limiting the generality of the invention, this description presents particular embodiments, where rebar adapters are used with structure-lining apparatus used to fabricate lining structures that line existing structures.

[0030] Figure 2 shows a partial shallow perspective view of a portion of a structure- lining apparatus 100 according to an example embodiment wherein rebar members 14 (only one of which is visible in Figure 2) are supported or otherwise accommodated by way of rebar adapters 200. Figures 3A, 3B and 3C, show various views of rebar adapter 200 in isolation. Structure- lining apparatus 100 of Figure 2 comprises standoffs 120, lining surface 130, rebar members 14 and rebar adapters 200. Lining surface 130 extends in transverse directions indicated by double- headed arrow 30 and in longitudinal directions indicated by double-headed arrow 32. Standoffs 120 are connected to lining surface 130 at connections 121 and extend in an inward direction (indicated by arrow 36) from lining surface 130 toward existing structure 15. Rebar member 14 extends in transverse direction 30 through apertures 124 in standoffs 120 and is rigidly anchored to existing structure 15 by rebar anchors 16.

[0031] A number of directional conventions are used throughout this description and in the accompanying claims. The transverse directions 30 and longitudinal directions 32 shown in Figure 2 may be orthogonal to one another and may be in a plane that is tangential to the outward surface of existing structure 15 at a particular location and/or to lining surface 130 at a particular location. Inward direction 36 may be orthogonal to both transverse direction 30 and longitudinal direction 32 and may be oriented toward existing structure 15. Outward direction 34 may also be orthogonal to both transverse direction 30 and longitudinal direction 32 and may be oriented away from existing structure 15.

[0032] Referring to Figure 2, rebar member 14 extends in transverse direction 30 through apertures 124 in standoffs 120 and is rigidly anchored to existing structure 15 by rebar anchors 16. In the Figure 2 embodiment, rebar anchors 16 comprise J-bolts 16A similar to those described above in connection with Figure 1. Rebar anchors 16 are rigidly anchored to existing structure 15 and comprise rebar receivers 16B (e.g. the hook portions of J-bolts 16A). Rebar receivers 16B receive rebar members 14 and are shaped to prevent rebar members 14 from moving in an outward direction (indicated by arrow 34) away from existing structure 15. In other embodiments, rebar anchors 16 may be implemented by any other suitable mechanism which is capable of being rigidly anchored to existing structure 15 and which comprises a rebar receiver capable of receiving, and preventing outward movement of, rebar member 14. Non-limiting examples include J-bolts, L-bolts (having L-shaped rebar receivers) and eye-bolts (having closed or nearly closed loop rebar receivers).

[0033] In the illustrated Figure 2 embodiment, lining surface 130 comprises a plurality of longitudinally and transversely extending panels 132 disposed in edge-to-edge relationship with one another. In the illustrated embodiment, panels 132 are connected to one another at their transverse edges by way of standoffs 120 and connections 121. In the Figure 2 embodiment, connections 121 are formed between C-shaped female connector components 134 of edge- adjacent panels 132 and a pair of complementary T-shaped male connector components 122 of standoff 120. When standoffs 120 are used in this manner to connect a pair of edge-adjacent panels 132 at connections 121, standoffs 120 may be referred to as connectors 120. It is not necessary that standoffs 120 connect edge-adjacent panels. In some embodiments, standoffs 120 may each be connected to a single panel. In other embodiments, standoffs may be integrally formed with panels. In Figure 2, standoffs 120 are oriented to extend directly inwardly (direction 36) from lining surface 130 and directly longitudinally (direction 32). This is not necessary. In some embodiments, standoffs 120 may extend inwardly from lining surface 130 and

longitudinally, but not directly in these directions (i.e. standoffs 120 may be oriented to have components which are oriented inwardly and longitudinally). Standoffs 120 are coupled through rebar adapters 200 to rebar member 14 (as explained in more detail below) and may: locate lining surface 130 relative to rebar member 14 and/or existing structure 15; space lining surface 130 apart from rebar member 14 and/or existing structure 15; and/or the like.

[0034] In the illustrated embodiment of Figure 2, rebar member 14 extends transversely through apertures 124 of standoffs 120. Apertures 124 are formed in body 126 of standoffs 120 to allow for passage of both rebar member 14 and curable material (e.g. concrete) during fabrication of a lining structure. Rebar adapters 200 are located in a vicinity of the location where rebar member 14 extends through apertures 124 and, each rebar adapter comprises a standoff connector 220 for coupling to standoffs 120 and a rebar support 210 for coupling to rebar member 14. Standoff connectors 220 of rebar adapters 200 may be coupled to heads (also referred to as anchors) 125 of standoffs 120. Rebar adapters 200 may reduce the risk of damage to, plastic deformation of, or dislodgement of standoffs 120 by reducing stress concentrations and providing a larger surface area to distribute the force between rebar member 14 and standoffs 120 through rebar adapters 200. [0035] In particular embodiments, standoffs 120 and panels 132 of lining surface 130 are fabricated from suitable plastic as monolithic units using an extrusion process. Similarly, in particular embodiments, rebar adapters 200 are fabricated from suitable plastic as monolithic units and may be fabricated using injection molding or any other suitable technique. By way of non-limiting example, suitable plastics for these components include: poly- vinyl chloride (PVC), acrylonitrile butadiene styrene (ABS) and/or the like. Standoffs 120 and panels 132 are not limited to plastic. In some embodiments, standoffs 120 and/or panels 132 could be fabricated from other suitable materials, such as suitable metals or the like.

[0036] For some structure- lining apparatus, the use of plastic components may increase the ease of production. However, as discussed above, in prior art systems without rebar adapters, the use of plastic may in some cases contribute to the damage to, plastic deformation of, and/or misalignment of, the standoffs by the rebar members. This may be due, in part, to the difference in material strength between the plastic standoffs and the rebar members (typically fabricated from suitable steel alloys). Also, it may be difficult to produce standoffs having relatively large contact surfaces to receive rebar members, in part due to the limitations of extrusion processes and/or due to a desire to reduce the amount of material required to produce standoffs. Rebar adapters, such as rebar adapter 200, may be produced separately and installed as necessary to support rebar members 14 and/or to connect rebar members 14 to part of the structure-lining apparatus 100 (e.g. to standoffs 120).

[0037] Figures 3A-3C are perspective, front elevation, and side elevation views respectively of rebar adapter 200 used in the Figure 2 structure- lining apparatus 100. Rebar adapter 200 comprises rebar support 210, standoff connector 220 and standoff receiver 230. In the illustrated embodiment, rebar support 210 is shaped to provide a transversely extending and outwardly opening rebar-support concavity 211 which is shaped to receive a portion of a transversely extending cylindrical rebar member 14. In particular, rebar support 210 of the Figure 3 embodiment comprises a semi-cylindrical support surface 212 comprising a pair of transversely and outwardly extending arms 214A, 214B (together, arms 214) which are generally arc-shaped in cross-section. The outwardmost ends 218A, 218B (together, ends 218) of arms 214 are spaced apart from one another, creating an outwardly oriented opening 213. In other embodiments support surface 212 (and its transversely and outwardly extending arms 214) may have other cross-sectional shapes to accommodate rebar members 214 having other cross-sectional shapes. For example, support surface 212 may be shaped to be complementary to rebar members 14 having elliptical cross-section, rectangular cross section, triangular cross-section, or the like. Support surface 212 may provide a contact surface area with a greater dimension in transverse direction 30 than a corresponding standoff 120 to which it may be coupled (see Figure 2 for example).

[0038] In the particular case of the Figure 3 embodiment, transversely and outwardly extending arms 214 of rebar support 210 extend from a central portion 202 of rebar adapter 200. In this particular embodiment and as best seen in Figure 3C, arms 214 extend away from one another at a root 215 to reach a widest point 216 (in longitudinal direction 32) and extend towards one another at ends 218. Such a configuration provides an opening having increasing longitudinal dimension from root 215 to widest point 216, and narrowing longitudinal dimension from widest point 216 to ends 218. The longitudinal dimension of outwardly oriented opening 213 at ends 218 may be less than a longitudinal dimension (e.g. a diameter) of rebar member 14 and may also be less than the longitudinal dimension of rebar-support concavity 211 at widest point 216. In the Figure 3 embodiment, arms 214 (or at least ends 218 of arms 214) may be formed of a resiliently deformable material such as appropriate plastics described above. The resiliently deformable nature of arms 214 permits rebar member 14 to be coupled to rebar support 210 by pressing rebar member 14 inwardly into opening 213 at ends 218. Arms 214 are then caused to deform apart from one another in longitudinal direction 32 as rebar member 14 is inserted inwardly through opening 213 and, as rebar member 14 begins to pass inwardly through opening 213 into rebar-support concavity 211, to resiliently restore (e.g. "snap" back) to a less deformed state around rebar member 14 until rebar member 14 is located in rebar-support concavity 211. Because of the deformation of one or both of arms 214, the coupling of rebar member 214 to rebar support 210 of rebar adapter 200 may be referred to as a "snap-together" connection. In some embodiments, arms 214 remain partially deformed when rebar member 14 is coupled to rebar support 210 such that arms 214 continue to assert restorative forces (i.e. forces that tend to restore arms 214 to their undeformed state) on rebar member 14 when rebar member 14 is coupled to rebar support 210.

[0039] With rebar member 14 coupled to rebar support 210, rebar member 14 may be supported by support surface 212. As mentioned, support surface 212 may comprise a variety of shapes that are complementary to the cross-sectional shape of rebar 214. Similarly, transversely and outwardly extending arms 214 may comprise a variety of generally concave cross-section shapes and extend longitudinally away from one another at root 215 to reach a widest point 216 and extend back toward one another at ends 218 to form a snap-together connection. For example, arms 214 may extend away from root 215 as flat planes to their respective widest points 216, then back toward one another as flat planes to their respective ends 218.

[0040] In some embodiments, outwardly oriented opening 213 may have a longitudinal dimension that is greater than a longitudinal dimension (e.g. diameter) of rebar member 14. In such embodiments, rebar member 14 may still be coupled to and supported by rebar support 210, but may not necessarily be retained by arms 214. In still other embodiments, rebar support 210 may not have an opening 213. In such embodiments, arms 214 may be shaped to form a transversely extending tube of suitable cross-sectional shape to accommodate the slidable transverse insertion of rebar member 14 therethrough.

[0041] Rebar adapter 200 also comprises standoff connector 220 which couples rebar adapter 200 to a portion of standoff 120 (see Figure 2). In this example Figure 3 embodiment, standoff connector 220 is shaped to provide a longitudinally extending and inwardly opening standoff- connector concavity 221 which is shaped to receive a longitudinally extending portion of a corresponding one of standoffs 120. In particular, standoff connector 220 of the Figure 3 embodiment comprises a pair of longitudinally and inwardly extending branches 222A, 222B (together, branches 222) that extend from central portion 202 of rebar adapter 200. Branches 222 define standoff-connector concavity 221 and are transversely spaced apart from one another at their inward ends to define an inwardly oriented opening 224. The transverse dimension of opening 224 may be less than a transverse dimension of standoff-connector concavity 221. [0042] Branches 222 of the Figure 3 embodiment comprise longitudinally extending beveled surfaces 226A, 226B (together, beveled surfaces 226) in a vicinity of opening 224, which extend transversely toward one another as they extend into standoff-connector concavity 221. Branches 222 are shaped to provide longitudinally extending hooks 227A, 227B (together, hooks 227) which are shaped to define outwardly opening hook concavities 229 A, 229B (together, hook concavities 229). As seen in Figures 3A and 3B, hook concavities also open toward standoff- connector concavity 221. As described further below, standoff connector 220 connects to standoff 120 by way of insertion of head 125 into standoff-connector concavity 221 through opening 224 such that hooks 227 of branches 222 constrain head 125 of standoff 120 within standoff-connector concavity 221.

[0043] Rebar adapter 200 also comprises standoff receiver 230 as shown best in Figures 3A and 3B. Standoff receiver 230 of the Figure 3 example embodiment comprises a longitudinally extending standoff-receiver slot 232 that opens inwardly into standoff-connector concavity 221 for receiving a second portion (e.g. body 126) of standoff 120 (see Figures 4A-4D). In the illustrated embodiment, standoff- receiver slot 232 extends longitudinally through rebar adapter 200 and has a width that tapers slightly from its inwardly oriented opening 234 to its base 236. The cross-sectional shape of standoff-receiver slot 232 is generally complementary to the corresponding cross-sectional shape of body 126 of standoff 120. As body 126 of the illustrated embodiment is planar with a generally rectangular cross-section, standoff-receiver slot 232 is shaped to be similarly rectangular. This is not necessary and body 126 and standoff- receiver slot 232 may have other cross-sectional shapes. For example, standoff-receiver slot 232 may have a V-shaped cross-section, where opening 234 has a wider transverse dimension that the remainder of standoff-receiver slot 232, as is the case in the illustrated embodiment. Such a cross-sectional shape may facilitate easier insertion of body 126 of standoff 120 into standoff-receiver slot 232.

[0044] Figures 4A-4D (together, Figure 4) show the process of coupling rebar adapter 200 to a standoff 120 according to an example embodiment. In Figure 4A, rebar adapter 200 is inserted into an aperture 124 of standoff 120. Standoff connector 220 of rebar adapter 200 may have a longitudinal dimension less than that of aperture 124 in standoff 124. In some embodiments, rebar adapter 200 may be dimensioned so as to be capable of passing transversely through aperture 124 of standoff 120. As seen in Figure 4B, standoff receiver 230 is aligned with body 126 of standoff 120 and standoff connector 220 is aligned with head 125 of standoff 120. To engage rebar adapter 200 with standoff 120, rebar adapter 200 is moved in inward direction 36 relative to standoff 120 (and/or standoff is move in outward direction 34 relative to rebar adapter 200). Branches 222 and in particular beveled surfaces 226 contact head 125. In the illustrated embodiment, head 125 comprises a pair of hooked legs 127A, 127B (together, legs 127). When rebar adapter 200 continues to be moved inwardly relative to standoff 120, interaction between beveled surfaces 226 and head 125 cause branches 222 to deform transversely apart from one another, expanding the transverse dimension of opening 224 until opening 224 is wide enough to accept head 125 (as shown in Figure 4C). In the illustrated embodiment, only branches 222 are deformed. This is not necessary, in some embodiments head 125 may be deformed; in some embodiments both head 125 and branches 222 may be deformed.

[0045] Once transverse opening 224 is wide enough to accept head 125, head 125 passes into standoff-connector concavity 221 between branches 222, as shown in Figure 4D. Hooks 227 of branches 222 engage legs 127 of head 125 or otherwise engage head 125. Also, body 126 of standoff 120 extends in outward direction 34 into standoff- receiver slot 232 of standoff receiver 230. Furthermore, once head 125 passes into standoff-connector concavity 221, branches 222 resiliently restore (e.g. "snap" back) to a less deformed state around head 125. As shown in Figure 4D, once head is received in standoff-connector concavity 221, hooks 127 of branches 222 constrain head 125, and rebar adapter 200 is coupled to standoff 120. In some embodiments, branches 222 remain partially deformed when standoff connector 220 is coupled to standoff 120, such that branches 222 continue to assert restorative forces (i.e. forces that tend to restore branches 222 to their undeformed state) on head 125 when standoff connector 220 is coupled to standoff 120.

[0046] In some embodiments, rebar member 14 is free to move (or can be moved with a suitable amount of force) in transverse direction 30 even when coupled to rebar support 210 of rebar adapter 200. That is, rebar member 14 may slide transversely within rebar support 210. This may provide the advantage that rebar adapter 200, standoff 120, and/or lining system 100 may be moved and positioned as desired in the transverse direction 30. For example, this may allow rebar adapters 200 and/or standoffs 120 to be coupled to rebar member 14 prior to positioning standoffs 120 and/or prior to connecting standoffs 120 to lining surface 130. In some embodiments, rebar member 14 and rebar adapter 200 may be free to move in longitudinal direction 32 relative to standoff 120 even when standoff connector 220 of rebar adapter 200 is coupled to standoff 120. That is, rebar adapter 200 may be able to slide longitudinally along head 125 within aperture 124. In embodiments where standoffs 120 have large apertures, the range of motion in the longitudinal direction 32 page may be larger than in embodiments having apertures of a size such as those shown in Figure 4A. The mobility of rebar adapter 200 relative to rebar member 14 and/or standoff 120 may also allow rebar adapter 200 to accommodate bends or kinks in rebar member 14. The mobility of rebar adapter 200 (both with rebar member 14 and relative to rebar member 14 and both with standoff 120 and relative to standoff 120) may provide enhanced flexibility during fabrication of a lining structure. In particular, components may be positioned within greater tolerances thereby increasing build efficiency and reducing waste.

[0047] Rebar adapter 200 and standoff 120 are not limited to the shapes illustrated in the Figures 2-4 embodiment. Figures 5A-5D (together, Figure 5) illustrate a number of example head shapes suitable for use with standoffs 120 of Figures 204B or standoffs of other embodiments. Figure 5A shows a head 525A having a rectangular cross-section. Figure 5B shows a head 525 B having a generally Y-shaped cross-section. Figure 5C shows a head 525C having a generally oval shaped cross-section. Figure 5D shows a head 525D having a generally W-shaped cross-section. Many other head shapes are possible and would provide appropriate attachment points for rebar adapters, such as rebar adapter 200 which could be fabricated with branches having suitably complementary shapes.

[0048] Rebar adapters 200 of the embodiment illustrated in Figures 2-4 may be used with standoffs 120 having any of the head shapes 125, 525A, 525B, 525C, 525D of Figures 2-4, Figure 5A, Figure 5B, Figure 5C and/or Figure 5D. In some embodiments, however, rebar adapters 200 may be modified to provide standoff connectors which have shapes that are complementary to the shapes of heads of standoffs 120. Figures 6A-6D (together, Figure 6) illustrate a number of example standoff-connector shapes 620 A, 620B, 620C and 620D

(together, standoff connectors 620) suitable for use with standoffs 120 having various head- shapes (shown in broken lines in Figure 6). Standoff connectors 620 shown in the Figure 6 example embodiments have characteristics similar to standoff connectors 120 described above. More particularly, standoff connectors 620 comprise inwardly opening standoff-connector concavities 621A, 621B, 621C, 621D (together standoff-connector concavities 612) defined by longitudinally and inwardly extending branches 622A, 622B, 622C, 622D (together branches 622), where branches 622 are shaped to provide hooks 627 A, 627B, 627C, 627D (together, hooks 627) having outwardly opening hook concavities 629A, 629B, 629C, 629D (together, hook concavities 629) and standoff receivers 630A, 630B, 630C, 630D (together standoff receivers 630) comprising longitudinally extending and inwardly opening standoff-receiver slots 632A, 632B, 632C, 632D (together, standoff-receiver slots 632). Standoff-connector concavities 621, branches 622, hooks 627, hook concavities 629, standoff receivers 630 and standoff- receiver slots 632 may have features similar to standoff connector concavities 221, branches 222, hooks 227, hook concavities 229, standoff receivers 230 and standoff-receiver slots 232 described above. As can be seen, branches 622 may be curved, straight, angled, bent or the like to accommodate the corresponding cross-sectional shape of heads 525. Also, hooks 627 may have a variety of shapes.

[0049] Other suitable shapes for heads 125 of standoffs 120 are disclosed, for example, in co- owned Patent Cooperation Treaty publication No. WO2010/078645 and Patent Cooperation Treaty publication No. WO2008/119178 which are hereby incorporated herein by reference.

[0050] Figure 7A shows another embodiment of a rebar adapter 700 and a portion of standoff 120 to which rebar adapter 700 may be coupled. Rebar adapter 700 comprises standoff connector 720 and rebar support 710. In the Figure 7A embodiment, standoff connector 720 comprises a single longitudinally and inwardly extending branch 722 comprising a hook 727 having an outwardly opening hook concavity 729. This configuration of standoff connector 720 may allow for rebar adapter 200 to be more easily coupled after rebar member 14 has been transversely extended through aperture 124 of standoff 120. This may be because rebar adapter 700 may be connected to head 125 of standoff 120 from a transverse side (i.e. in transverse direction 30) rather than by relative inward movement (i.e. in inward direction 36) relative to standoff 120.

[0051] Rebar support 710 of rebar adapter 700 may be similar in many ways to rebar support 210 of rebar adapter 200. In some embodiments, rebar support 710 may be transversely offset from the longitudinal extension of standoff 120. For example, Figure 7B shows rebar support 710 offset to one transverse side of standoff 120, while Figure 7C shows rebar support 710 offset to the other transverse side of standoff 120. As rebar member 14 may move in transverse directions 30 relative rebar support 710 when rebar adapter 700 is coupled to rebar member 14 (as described above for rebar support 210 and rebar adapter 200), rebar adapter 700 may be coupled to rebar member 14 at a location spaced apart from standoff 120 and then rebar adapter 700 may be moved transversely toward standoff 120, where rebar adapter may then be coupled to head 125 of standoff 120. In the Figure 7A and 7B embodiments, rebar support 710 may pass at least partially through an aperture 124 (not shown in Figure 7) of standoff 120 once rebar adapter 700 is coupled to standoff 120. In the Figure 7C embodiment it may be unnecessary for rebar support 710 to pass through an aperture 124 of standoff 120.

[0052] Figures 8A-8D (together, Figure 8) show another embodiment of a rebar adapter 800. Rebar adapter 800 comprises a rebar support 810, standoff connector 820 and standoff receiver 830 which may be similar in many respects of rebar support 210, standoff connector 820 and standoff receiver 830 of rebar adapter 200 described herein. Rebar adapter 800 differs from rebar adapter 200 in that rebar adapter 800 comprises a second rebar support 840. Standoff connector 820 of the Figure 8 embodiment is substantially similar to standoff connector 220 of rebar adapter 200 and, like standoff connector 220, standoff connector 820 may comprise any of the alternate standoff connector shapes, such as those shown in Figures 6A-6D. Standoff receiver 830 of the Figure 8 embodiment is substantially similar to standoff receiver 230 of rebar adapter 200. Second rebar support 840 is configured to support a second rebar member 14A oriented in a different direction to rebar member 14. In the illustrated Figure 8 embodiment, second rebar support 840 is configured to support a second, longitudinally oriented rebar member 14A.

[0053] Figures 8B, 8C, 8D show various views of rebar adapter 800 in isolation. Second rebar support 840 comprises a cradle 842 for supporting second, longitudinally extending rebar member 14A (Figure 8A). Cradle 842 of the Figure 8 embodiment extends in longitudinal direction 32, opens in inward direction 36 and has a semi-circular cross-section shaped to receive a cylindrical portion of second rebar member 14A (Figure 8C). In other embodiments, cradle 842 may have other cross-sectional shapes that are complementary to the cross-sectional shape of second rebar member 14A. Second rebar support 840 also comprises an inwardly opening rebar- support concavity 843. Rebar-support concavity 843 may have a transvers dimension greater than a transverse dimension of second rebar member 14A or may have a transvers dimension less than a transverse dimension of second rebar member 14A. In embodiments where the transverse dimension of rebar-support concavity 843 is less than the transverse dimension of second rebar member 14A, second rebar support 840 may comprise a snap-together connection similar in many ways to rebar support 210 described above.

[0054] Distal leg 847 of second rebar support 840 of the Figure 8 embodiment also comprises a loop 844 for receiving transversely extending primary rebar member 14. Loop 844 is shown in the Figure 8 embodiment as being a closed loop (i.e. with a fully closed cross-sectional shape). This is not necessary; loop 844 may have an inwardly opening shape in some embodiments and in some embodiments may comprise arms which deform to accept transversely extending primary rebar member 14. Loop 844 may comprise a snap-together connection. In the illustrated embodiment, rebar support 810 also comprises a closed loop 812 as seen best in Figure 8D. In some embodiments, transversely extending primary rebar member 14 may be extended through closed loop 812 after rebar adapter 800 has been connected to a standoff 120 via standoff connector 820. In other embodiments, transversely extending primary rebar member 14 may be extended through closed loop 812, then transversely extending primary rebar member 14 may be positioned with respect to the standoff(s) (e.g. standoffs 120) and rebar adapter(s) 800 may be connected to standoff(s) 120. [0055] In the Figure 8 embodiment, cradle 842 is located further outwardly from standoff connector 820 than rebar support 810 such that second longitudinally extending rebar memberl4A would be located on an outward side of transversely extending primary rebar member 14. This is not necessary. In some embodiments, cradle 842 and/or second rebar support 840 may be located on the inward side of rebar support 810. In such embodiments, second longitudinally extending rebar member 14A would be located inwardly of transversely extending primary rebar member 14.

[0056] Figure 9 shows an embodiment of a structure-lining apparatus 900 according to an example embodiment of the invention. Structure- lining apparatus 900 is similar in many respects to structure-lining apparatus 100 with similar components being referenced with a leading numeral "9" rather than a leading numeral "1". Structure-lining apparatus 900 differs from structure-lining apparatus 100 primarily in that lining surface 930 comprises a plurality of panels 932 connected directly to one another via edge-connections 921 (rather than being connected to one another via standoffs 120 (see connections 121 of structure- lining apparatus 100). Edge- connections 921 are made between edge-connector components 933A, 933B on transverse edges of edge-adjacent panels 932. Edge-connections 921, edge connector components 933A, 933B and panels 932 may correspond to those described in, for example, Patent Cooperation Treaty publication No. WO2009/059410, which is incorporated herein by reference.

[0057] In the Figure 9 embodiment, each standoff 920 is connected to a single panel 932 by way of female C-shaped connectors 934 and male T-shaped connectors 922. C-shaped connectors 934 may be adjacent to edge-connections 921 or may be located elsewhere on panels 932. Other forms of connectors may be used as is known in the art.

[0058] Figure 10 shows an embodiment of a structure-lining apparatus 1000 according to an example embodiment of the invention. Structure-lining apparatus 1000 is similar in many respects to structure-lining apparatus 100 with similar components being referenced with a leading numeral "10" rather than a leading numeral "1". Structure-lining apparatus 1000 differs from structure-lining apparatus 100 primarily in that panels 1032 are shaped to provide a double- layered lining surface 1030 which comprises an outward lining surface 1030A and an inward lining surface 1030B. This double-layered lining surface 1030 may reduce bowing of panels 1032 under the weight of liquid concrete. Panels having this double-layered configuration are described in PCT patent application published under No. WO/2013/075250 which is hereby incorporated herein by reference. Structure-lining apparatus 1000 also differs from structure- lining apparatus 100 in that rebar anchors 1016 have shapes that are different from rebar anchors 16. More particularly, rebar anchors 1016 comprise rebar receiver portions that are L-shaped (rather than the J-shaped rebar receiver portions of rebar anchors 16). The shape of L-shaped rebar anchors 1016 still provides the same functionality as J-shaped rebar anchors 16 in the sense that rebar anchors 1016 may be rigidly anchored to existing structure 15 and comprise rebar receivers shaped to receive a rebar member 14 and to prevent movement of the rebar member 14 in an outward direction away from the existing structure when rebar anchor 1016 is anchored to existing structure 15. In other respects (e.g. standoffs 120 and rebar adapters 200), structure- lining apparatus 1000 may be similar to structure-lining apparatus 100 described above.

[0059]While a number of exemplary aspects and embodiments are discussed herein, those of skill in the art will recognize certain modifications, permutations, additions and subcombinations thereof. For example:

• Rebar member 14 may be located and installed without rebar anchors 16 and/or without existing structure 15. For example, rebar member 14 may be supported by components of a formwork at either end of rebar member 14 such that rebar anchors 16 (or other anchoring components) is unnecessary. Similarly, rebar anchors 16 may be rigidly anchored to other structural components (e.g. formwork components and/or the like) - i.e. such that rigid anchoring of rebar anchors to existing structure 15 is unnecessary.

• Existing structures 15 may be fabricated from concrete. This is not necessary, however, and existing structures may generally be fabricated from any suitable structural material, such as: wood, metal, stone, brick, combinations of these materials and/or the like.

• Other configurations of structure-lining apparatus may be used. For example, the lining surface may comprise a push-on lining surface that is installed onto the standoffs by pushing the panels in directions towards existing structure 15. Figure 11 which shows an example embodiment of a stnicture-lining apparatus 1100 comprising push-on panels 1132 of this type. Structure-lining apparatus 1100 is similar in many respects to structure-lining apparatus 100 with similar components being referenced with a leading numeral "11 " rather than a leading numeral "1". Structure-lining apparatus 1100 differs from structure-lining apparatus 100 primarily in that panels 1132 have connector components at their transverse edge (and standoff 1120 have complementary connector components at their outward edges) which permit connections 1121 between panels 1132 and standoffs 1120 to be made by inward movement of panels 1132 relative to standoffs 1120. In the illustrated Figure 11 embodiment, structure-lining apparatus 1100 also includes caps 1125 which complete connectors 1121 between panels 1132 and standoffs 1120, although, in some embodiments, caps 1125 are not necessary. Structure-lining apparatus 1100 also differs from structure-lining apparatus 100 in that standoffs 1120 also connect to panels 1132 by connections 1123 at locations away from the transverse edges of panels 1132, although such connections 1123 are not necessary or may differ in number. Panels 1132 and push-on connections 1121, 1123 are described, for example, in the PCT patent application published under No. WO/2012/003587 which is hereby incorporated herein by reference. Structure-lining apparatus 1100 also differs from structure-lining apparatus 100 in that rebar adapters 1116 are similar to rebar adapters 1016 described above for structure-lining apparatus 1000. In other respects (e.g. heads 125 of standoffs 1120 and rebar adapters 200), ), structure-lining apparatus 1100 may be similar to structure-lining apparatus 100 described above.

• Rebar adapters 200 and hooks 227 may pierce heads 125 or be inserted into gaps formed therein.

• Rebar adapters 200 may connect between two heads 125 that are spaced apart either in

transverse direction 30 or longitudinal direction 32. In such embodiments, branches 222 may extend between heads 125.

[0060] While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and subcombinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as consistent with the description and drawings as a whole.