WO2022219343A1

WO2022219343A1 - Modular wall unit

Info

Publication number: WO2022219343A1
Application number: PCT/GB2022/050940
Authority: WO
Inventors: Calum ENDEAN; Michael Roddy
Original assignee: Poundfield Precast Limited
Priority date: 2021-04-16
Filing date: 2022-04-13
Publication date: 2022-10-20
Also published as: GB202105422D0; GB2605835A

Abstract

The present invention provides a precast wall section for constructing a modular retaining wall comprising a plurality of said wall sections. The precast wall section comprises first and second outer faces, first and second end faces for abutting respective end faces of adjacent wall sections when arranged in the retaining wall, an internal cavity accessible from at least one of the end faces, and cast-in fasteners for securing connecting members thereto for securing the wall section to an adjacent wall section. The cast-in fasteners are positioned for access from within the cavity.

Description

MODULAR WALL UNIT

FIELD OF THE INVENTION

The present invention relates to a modular retaining wall section, a modular retaining wall system and a method of constructing a modular retaining wall.

BACKGROUND TO THE INVENTION

Modular retaining walls are widely used for containing bulk materials. It is known for such walls to be constructed from wall sections in the form of precast concrete blocks, which can be easily transported to a site and positioned (for example using a fork-lift) to create a wall. Each wall section may be free-standing, and a wall of desired length can be constructed by placing a suitable number of sections adjacent to one another. The sections may be secured to one another to distribute load more evenly through the wall so as to increase the overall strength of the wall, and to reduce the risk of the wall sections moving relative to one another. The sections are typically secured together using metal straps which span between the outer surfaces of adjacent sections and are bolted to cast-in fasteners in each adjacent section. The sections may also be secured to a ground surface using fasteners that extend through a base of the wall. An example of such a wall system is disclosed in the present applicant’s granted UK Patent No. 2377949, in which wall sections with “A”- shaped cross-sections are described.

In such prior art arrangements, fastening components such as straps and bolts are exposed on an outer face of the wall and may therefore be more vulnerable to damage in certain circumstances, for example from machinery used to handle the material contained by the wall, or from corrosion. Furthermore, the fastening components are exposed to the elements on the outer face, so that the fastening components and the concrete block may be susceptible to degradation.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a precast wall section for constructing a modular retaining wall comprising a plurality of said wall sections. The precast wall section comprises first and second outer faces, first and second end faces for abutting respective end faces of adjacent wall sections when arranged in the retaining wall, an internal cavity accessible from at least one of the end faces, and cast-in fasteners for securing connecting members thereto for securing the wall section to an adjacent wall section. The cast-in fasteners are positioned for access from within the cavity.

With this arrangement, when the wall sections are arranged in the retaining wall, the cast-in fasteners and connecting members are disposed within a hollow interior of the retaining wall instead of being exposed on an outer face of the wall, and may therefore be less vulnerable to damage and degradation. In this way, the outer faces of the wall sections can be substantially free of parts for securing the wall sections together, so that the outer faces of the retaining wall may be uninterrupted by the securing or connecting parts and the retaining wall may be more durable, less susceptible to damage due to equipment or materials contacting the connecting parts, and may have an improved appearance.

Preferably, each of the cast-in fasteners comprises a threaded insert for receiving a bolt. In other embodiments, the cast-in fasteners may comprise pins, shackles, eye bolts, threaded rods or other suitable fasteners. The cast-in fasteners may protrude into the cavity, or may be flush with or recessed into the walls of the cavity.

The wall section may comprise cast-in reinforcing elements coupled to the cast-in fasteners. The reinforcing elements may be arranged to transfer load applied to the cast-in fasteners into the wall section. In this way, the reinforcing elements help to prevent the cast-in fasteners from being pulled out of the wall section under load. Each reinforcing element may be connected to a respective cast-in fastener. The reinforcing elements may be formed from metal.

Each of the reinforcing elements may be elongate to extend in a direction away from the end face closest to the respective cast-in fastener. Each reinforcing element may be angled to diverge from a surface of the cavity. Each reinforcing element may comprise a connecting portion for connecting to a cast-in fastener and at least one elongate anchor portion which extends away from the fastener to anchor the reinforcing element in the wall section.

The depth or distance between the elongate anchor portion and an adjacent surface of the cavity may increase moving in a direction away from the cast-in fastener.

Preferably, each reinforcing element comprises a generally U-shaped staple. A base of the staple may extend part way around a respective cast-in fastener to provide the connecting portion and arms of the staple provide the anchor portions.

The wall section may comprise a metal reinforcing structure. For example, the wall section may comprise a reinforcing steel grid structure. The reinforcing elements may be disposed between a surface of the cavity and the metal reinforcing structure of the wall section. The reinforcing elements may be separate from the metal reinforcing structure.

The cavity may be at least partly defined by a floor and side walls. The cast-in fasteners are preferably disposed on the side walls of the cavity. Alternatively, or in addition, the cast-in fasteners may be disposed on the floor of the cavity. Preferably, the cavity is not accessible from the outer faces.

The wall section may comprise through-holes in the floor for securing the wall section to a ground surface.

The cavity may be divided into a first cavity part and a second cavity part. Cast-in fasteners may be positioned for access from within either or both of the first and second cavity parts.

The wall section may comprise one or more lifting inserts. Each lifting insert may comprise a cast-in lifting insert provided in a top surface of the wall section. The wall section may be lifted solely by the lifting inserts. In this way, the wall section may be conveniently lifted into position and/or manoeuvred when constructing the wall.

At least part of the wall section may have a generally A-shaped cross-sectional profile. In particular, the wall section may comprise a base portion, a first side portion, and a second side portion. The first and second side portions may extend upwardly and meet at an apex above the base portion and the base portion may extend between the first and second side portions. The first and second side portions may provide the first and second outer faces.

Preferably, the outer faces are substantially planar. The outer faces may be sloped to converge towards a top of the wall section. The outer faces may not be parallel to one another.

Preferably, when the wall sections are arranged in the retaining wall, the first and second outer faces are aligned with respective first and second outer faces of adjacent wall sections, to provide first and second faces of the wall.

The wall section may comprise an extension portion which projects upwardly from upper edges of the outer faces to increase a height of the wall section.

According to a second aspect of the invention there is provided a modular wall system for constructing a retaining wall. The system comprises two or more pre cast wall sections, each wall section comprising first and second outer faces, first and second end faces for abutting respective end faces of adjacent wall sections when arranged in the retaining wall, an internal cavity accessible from at least one of the end faces, and cast-in fasteners positioned for access from within the cavity, for securing connecting members thereto for securing the wall section to an adjacent wall section. The system further comprises connecting members for securing to the cast-in fasteners to secure the wall sections together. When the wall sections are arranged in the retaining wall, the cavities are aligned to form a hollow and the connecting members are positioned for access from within the hollow. Preferably the connecting members are disposed within the hollow.

According to a third aspect of the invention there is a provided a method of constructing a modular retaining wall using wall sections, each wall section comprising an internal cavity and cast-in fasteners positioned for access from within the cavity. The method comprises placing a first wall section, placing a second wall section adjacent the first wall section to align the cavity of the second wall section with the cavity of the first wall section to form a hollow, abutting an end face of the first wall section with an end face of the second wall section, placing a connecting member in the hollow to span between the first and second wall sections, fastening the connecting member to a cast-in fastener of the first wall section, and fastening the connecting member to a cast-in fastener of the second wall section.

Preferred and/or optional features of each aspect and embodiment of the invention may also be used, alone or in appropriate combination, in the other aspects and embodiments also.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which like reference numbers are used for like features and in which:

Figure 1 is a perspective view of a precast block according to a first embodiment of the invention;

Figure 2 is a schematic end view of the block of Figure 1 showing the position of various internal components;

Figure 3 is a schematic side view of the block of Figure 1 showing the position of various internal components;

Figure 4 is a perspective view of a wall comprising blocks according to the first embodiment of the invention;

Figure 5 is a cutaway view of the wall of Figure 4;

Figure 6 is a perspective view of a precast block according to a second embodiment of the invention;

Figure 7 is a schematic end view of the block of Figure 6 showing the position of various internal components;

Figure 8 is a schematic side view of the block of Figure 6 showing the position of various internal components;

Figure 9 is as perspective view of a wall comprising blocks according to the second embodiment of the invention; and

Figure 10 is a cutaway view of the wall of Figure 9. DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a modular wall system for constructing a freestanding modular retaining wall. The wall system comprises wall sections in the form of precast blocks. Two or more of the blocks may be joined together end-to- end to form the retaining wall.

A wall section according to a first embodiment of the invention, in the form of a precast block 100, is shown in Figures 1 to 5. In this embodiment, the block 100 is a reinforced concrete block having a steel reinforcing grid structure, known as a rebar mesh (not shown), cast within the block 100.

The block 100 comprises a generally rectangular base portion 102, a first side portion 104 and a second side portion 106. The first and second side portions 104, 106 rise at an angle from opposing side edges 108, 110 of the base portion and meet at an apex 112 above, and midway between the side edges 108, 110 of the base portion. The base portion 102 and first and second side portions 104, 106 extend between first and second end faces 114, 116 of the block, parallel to a longitudinal axis X of the block 100. Outer surfaces of the first and second side portions 104, 106 provide first and second outer faces 115, 117 of the block 100.

The base portion 102 and first and second side portions 104, 106 together define a cavity 118 which extends through the block and has a generally triangular cross section. The first and second side portions 104, 106 extend downwardly beyond the base portion 102 to form feet 120, 122, thereby forming a recess 124 beneath the base portion 102. In this way, a cross-sectional profile of the block 100 is similar in shape to a capital letter “A”. An upper surface of the base portion provides a floor 126 of the cavity 118. Inner surfaces of the side portions 104, 106 provide side walls 128, 130 of the cavity 118.

The block 100 is arranged to be secured to at least one other block 100 to form a wall. Accordingly, the block 100 comprises a plurality of cast-in fasteners for securing connecting members to join the block 100 to another block, as described further below. The cast-in fasteners are embedded in the block 100 and are arranged to be accessed from within the cavity 118.

In this embodiment, the cast-in fasteners are in the form of threaded inserts 132 arranged to receive the threaded shank of a bolt. Each threaded insert 132 (not shown in detail) comprises a cylindrical tube having an internal thread.

The threaded inserts 132 are recessed into a surface of the cavity 118, and each threaded insert 132 provides a blind bore which opens into the cavity 118. In particular, threaded inserts 132 are disposed in the base portion 102 and side portions 104, 106, to provide openings in the floor 126 and side walls 128, 130 of the cavity 118. The threaded inserts 132 are recessed into the block so as to sit flush with the inner (cavity-facing) surfaces of the floor 126 and side walls 128, 130. The threaded inserts 132 do not extend fully through the base portion 102 or side portions 104, 106 to reach an outer surface of the block 100. Accordingly, the threaded inserts 132 may be accessed only from within the cavity 118.

The threaded inserts 132 are disposed adjacent to, but spaced apart from, each end face 114, 116 of the block 100, to facilitate joining blocks together in an end-to-end arrangement. In the present embodiment, a pair of laterally spaced apart threaded inserts 132 is provided adjacent each end face 114, 116 of the block 100, in each of the base portion 102, the first side portion 104 and the second side portion 106. With this arrangement, six inserts 132 are provided adjacent each end face 114, 116 of the block 100 and the inserts 132 are generally evenly distributed around a periphery of the triangular cavity 118. In other embodiments, the cast-in fasteners may comprise pins, shackles, eye bolts, threaded rods (e.g. for accepting a nut) or other suitable fasteners, and any suitable number of fasteners may be provided. The cast-in fasteners may protrude into the cavity 118.

The block 100 further comprises reinforcing elements coupled to the cast-in fasteners. The reinforcing elements are arranged to transfer load applied to the cast- in fasteners into the block. As can be seen most clearly in Figures 2 and 3, in this embodiment, the reinforcing elements are cast-in reinforcing elements in the form of generally U-shaped staples 134, which may be formed from lengths of rebar. Each threaded insert 132 is provided with a corresponding staple 134 embedded in the block 100 beneath a surface of the cavity 118. The staples 134 are disposed entirely beneath the surface of the cavity 118.

Each U-shaped staple 134 comprises an engagement portion 136 formed by the base of the ‘U’ and elongate anchor portions 138 formed by the arms of the ‘U’. The engagement portion 136 wraps part way around a respective threaded insert 132 and the anchor portions 138 extend away from the threaded insert 132. The anchor portions 138 extend in a direction away from an adjacent end face 114 or 116 of the block 100. In this way, the anchor portions 138 extend generally away from the direction of load applied to the threaded inserts 132 in use, as described further below.

The staples 134 are angled to diverge from a surface of the cavity 118, as can be seen in Figure 3. In particular, each staple 134 is angled with respect to an adjacent surface of the cavity 118, such that the anchor portions 138 extend in a direction away from the cavity 118 as they extend away from the nearest adjacent end face 114 or 116 of the block 100. In this way, the engagement portion 136 of each staple 134 is disposed closer to the surface of the cavity 118 than the anchor portions 138. With these arrangements, the staples 134 help to transfer load into the block and thus help to prevent the threaded inserts 132 from failing under load and from being pulled out from the block 100. The staples 134 are embedded in the block 100 adjacent the surface of the cavity 118 and do not extend fully through the base portion 102 or side portions 104, 106 to reach the outer surface of the block 100. In other embodiments, each reinforcing element may comprise a loop, bar, hook or other suitably shaped element. Each reinforcing element may be fixed (e.g. welded) to a respective cast-in fastener before being cast into the block.

It may be desirable (for instance to improve durability by reducing corrosion) for a reinforcing grid in a reinforced concrete block to be covered by a predetermined minimum depth of concrete, to provide a barrier between the reinforcing grid and external elements to which the block is exposed. In the present embodiment, the threaded inserts 132 and staples 134 are separate from the reinforcing grid (not shown) of the block 100. The reinforcement provided by the staples allows shallower threaded inserts (or other cast-in fasteners) to be used, which need not be connected to the reinforcing grid. In this way, the reinforcing grid may be better protected against corrosion (e.g. from water ingress) which might otherwise spread inwardly from the surface of the block to the grid via the cast-in fasteners.

In use, a wall may be constructed from a plurality of blocks 100 by abutting the blocks 100 end-to-end, aligning the blocks 100 coaxially (with respect to the longitudinal axis X of each block). Figures 4 and 5 show a wall 10 comprising a first block 100a and a second block 100b. A first end face 114 of the first block 110a abuts a second end face 116 of the second block 110b. The outer faces 115, 117 form first and second faces 12, 14 of the wall 10. The cavities 118 of the blocks 100a, 100b are aligned to form a continuous generally triangular void or hollow 16 extending longitudinally through the wall 10. In this arrangement, each of the threaded inserts 132 adjacent the first end face 114 of the first block 110a is aligned with a corresponding threaded insert 132 adjacent the second end face 116 of the second block 100b.

As can be seen in Figure 5, the blocks 100a, 100b are secured together using connecting members (as mentioned above), which in this embodiment comprise connecting brackets 140. Figure 5 shows the wall 10 with the second side portions 106 of each block 100a, 100b omitted so that the brackets 140 can be seen within the hollow 16. The connecting brackets 140 are arranged to be secured to the threaded inserts 132 by bolts 142. Each connecting bracket 140 comprises a generally rectangular plate having a pair of spaced apart mounting apertures. In this embodiment, the mounting apertures comprise elongate slots 144. A width of each slot 144 is sized to receive a shank of one of the bolts 142. Each bracket 140 is arranged to extend between corresponding cast-in fasteners of adjacent blocks. In this case, each bracket extends between a threaded insert 132 of the first block 100a, and a corresponding threaded insert 132 of the adjacent second block 100b, in order to connect the blocks 100a, 100b together. Each bracket therefore extends from a cavity 118 of the first block 100a to a cavity 118 of the second block 100b.

The brackets 140 are secured in place by inserting a bolt 142 through each slot in the bracket 140 and tightening the bolt 142 into the respective threaded insert 132. The elongate slots 144 allow the brackets 140 to accommodate for variations in distance between corresponding inserts 132 and/or slight misalignment of adjacent blocks. With this arrangement, the brackets 140 are secured adjacent the floor 126 and side walls 128, 130 of the cavities 118. Securing brackets 140 to both the floor 126 and side walls 128, 130 of the cavities means that connecting brackets 140 span between the blocks 100a, 100b both near a base of the blocks, and also at a higher position, closer to the top of the blocks. This arrangement helps to strengthen the wall 10 against lateral and torsional forces acting to deflect blocks out of alignment with the wall 10.

It will be appreciated that, once adjacent blocks are butted against one another, access to the threaded inserts 132 for securing the brackets 140 in place is possible only through the cavities 118 of the blocks. The threaded inserts 132 and brackets 140 are sheltered in the hollow 16 which extends through the wall 10. In this way, the inserts 132, brackets 140 and bolts 144 may be protected from damage. In this embodiment, the end faces 114, 116 of each block 100 are generally smooth and generally planar, such that a substantially uninterrupted joint is formed between the blocks 100a, 100b when the blocks are abutted. This joint may be sealed once the wall 10 has been constructed. Edges of the end faces 114, 116 may be chamfered to help prevent chipping, which may occur as the blocks are manoeuvred whilst constructing the wall 10.

In this embodiment, the outer faces 115, 117 are smooth and generally planar. The side portions 104, 106 are aligned when the wall 10 is constructed, such that the outer faces 115, 117 form first and second faces 12, 14 of the wall 10. In this way, the faces 12, 14 of the wall are generally planar and interrupted only by the joints between blocks. As can be seen from Figures 4 and 5, the connecting brackets 140 and bolts 144 for securing the blocks 100a, 100b together are disposed within the hollow 16 and are therefore protected from hazards to which the outer faces 12, 14 of the wall are exposed. For example, the brackets 140 and bolts 144 are protected from being struck by machinery used for handling bulk materials, and from exposure to abrasive or corrosive substances to which the outer faces 12, 14 may be exposed. This arrangement also helps to improve the appearance of the wall, as the faces 12, 14 of the wall are not interrupted by the brackets 140.

The block 100 described above may be readily manoeuvred using a fork-lift, crane or other suitable equipment, for example by inserting a fork or forks or a lifting strap into the cavity 118 of the block 100. Each block 100 is also provided with cast-in lifting inserts 146 set into a top surface of the block 100. The block 100 may be liftable solely by the lifting inserts 146.

The block 100 further comprises fixing holes 148 which pass through the base portion 102. The fixing holes 148 are arranged to receive ground fixings for fixing the block 100 to a ground surface. For example, the block 100 may be secured to a ground surface by bolts which extend through the fixing holes and are secured to the ground surface or driven into the ground. In some embodiments, a ground fixing system (not shown) comprising elongate rail members may be fixed to the ground surface. The blocks may be placed over the ground fixing system such that the wall extends over the rail members, and the blocks may be secured to the rail members with suitable fasteners which extend through the fixing holes 148.

A precast block 200 according to a second embodiment of the invention is shown in Figures 6 to 10. The block 200 is similar to the block 100 of the first embodiment, and only the differences will be described in detail.

The block 200 of this second embodiment comprises a base portion 202 and first and second side portions 204, 206. Referring in particular to Figures 6 and 7, the block 200 comprises a bridging portion 205 which spans a width of a generally triangular cavity of the block 200 and divides the cavity into a first, upper cavity part

218 and second, lower cavity part 219. The bridging portion is generally rectangular and extends between the first and second side portions 204, 206 of the block 200 and between first and second end faces 214, 216 of the block. The lower cavity part

219 has a generally trapezium-shaped cross section. The upper cavity part 218 has a generally triangular cross section. Referring also to Figure 8, in this second embodiment, threaded inserts 132 are provided in a floor 245 and side walls 250, 252 of the lower cavity part 219 and in side walls 228, 230 of the upper cavity part 218. In some embodiments, threaded inserts (or other cast-in fasteners) may be provided in an upper side and/or a lower side of the bridging portion 205. The block 200 is provided with lifting inserts 246, and fixing holes 248 pass through the base portion 202.

Figure 9 shows a wall 20 constructed from first and second blocks 200a, 200b according to the second embodiment, and Figure 10, shows the wall 20 with the second side portions 206 of each block 200a, 200b omitted. The blocks 200a, 200b are aligned such that the upper cavity part 218 of the first block 200a is aligned with the upper cavity part 218 of the adjacent second block 200b to form an upper hollow 26 extending through the wall 20. The lower cavity part 219 of the first block 200a is aligned with the lower cavity part 219 of the second block 200b to form a lower hollow 28 extending through the wall 20. To join the blocks together, connecting brackets 140 are positioned to extend between corresponding threaded inserts 132 of the adjacent blocks 200a, 200b. In this embodiment, threaded inserts 132 are provided in both the upper and lower cavity parts 218, 219, such that brackets may be secured in both the upper and lower hollows 26, 28.

In some embodiments (not shown), the block may comprise an extension portion which projects upwardly from the apex of the block to increase a height of the block. The extension portion may be generally rectangular. In some embodiments, the extension portion may have a hollow interior.

It will be appreciated that the wall system of the present invention provides a modular wall in which adjacent wall sections in the form of blocks are secured together by connecting members disposed within a hollow interior of the wall. Adjacent blocks are secured to one another by brackets which span between the blocks. In this way, load applied to each block in the wall is distributed along the wall, which helps to strengthen the wall.

Further modifications and variations not explicitly described above can also be contemplated without departing from the scope of the invention as defined in the appended claims.

Claims

1. A precast wall section for constructing a modular retaining wall comprising a plurality of said wall sections, the precast wall section comprising: first and second outer faces; first and second end faces for abutting respective end faces of adjacent wall sections when arranged in the retaining wall; an internal cavity accessible from at least one of the end faces; and cast-in fasteners for securing connecting members thereto for securing the wall section to an adjacent wall section; wherein the cast-in fasteners are positioned for access from within the cavity.

2. A wall section according to Claim 1 , comprising cast-in reinforcing elements coupled to the cast-in fasteners, the reinforcing elements being arranged to transfer load applied to the cast-in fasteners into the wall section.

3. A wall section according to Claim 2, wherein each of the reinforcing elements is elongate to extend in a direction away from the end face closest to the respective cast-in fastener.

4. A wall section according to Claim 3, wherein each reinforcing element is angled to diverge from a surface of the cavity.

5. A wall section according to any of Claims 2 to 4, wherein each reinforcing element comprises a connecting portion for connecting to a cast-in fastener and at least one elongate anchor portion which extends away from the fastener to anchor the reinforcing element in the wall section.

6. A wall section according to Claim 5, wherein each reinforcing element comprises a generally U-shaped staple wherein a base of the staple extends part way around a respective cast-in fastener to provide the connecting portion and arms of the staple provide the anchor portions.

7. A wall section according to any of Claims 2 to 6, wherein the reinforcing elements are disposed between a surface of the cavity and a metal reinforcing structure of the wall section.

8. A wall section according to Claim 7, wherein the reinforcing elements are separate from the metal reinforcing structure.

9. A wall section according to any preceding claim, in which the cavity is at least partly defined by a floor and side walls and the cast-in fasteners are disposed on the side walls.

10. A wall section according to Claim 9, comprising through-holes in the floor for securing the wall section to a ground surface.

11. A wall section according to any preceding claim, in which each of the cast-in fasteners comprises a threaded insert for receiving a bolt.

12. A wall section according to any preceding claim, in which the cavity is divided into a first cavity part and a second cavity part.

13. A wall section according to any preceding claim, wherein at least part of the wall section has a generally A-shaped cross-sectional profile.

14. A wall section according to any preceding claim, in which the outer faces are substantially planar.

15. A wall section according to any preceding claim, comprising an extension portion which projects upwardly from upper edges of the outer faces to increase a height of the wall section.

16. A modular wall system for constructing a retaining wall, the system comprising: two or more pre-cast wall sections, each wall section comprising: first and second outer faces; first and second end faces for abutting respective end faces of adjacent wall sections when arranged in the retaining wall; an internal cavity accessible from at least one of the end faces; and cast-in fasteners positioned for access from within the cavity, for securing connecting members thereto for securing the wall section to an adjacent wall section; connecting members for securing to the cast-in fasteners to secure the wall sections together; wherein, when the wall sections are arranged in the retaining wall the cavities are aligned to form a hollow and the connecting members are positioned for access from within the hollow.

17. A system according to Claim 16, wherein, in use, the connecting members are disposed within the hollow.

18. A method of constructing a modular retaining wall using wall sections, each wall section comprising: an internal cavity; and cast-in fasteners positioned for access from within the cavity; the method comprising: placing a first wall section; placing a second wall section adjacent the first wall section to align the cavity of the second wall section with the cavity of the first wall section to form a hollow and to abut an end face of the first wall section with an end face of the second wall section; placing a connecting member in the hollow to span between the first and second wall sections; fastening the connecting member to a cast-in fastener of the first wall section; fastening the connecting member to a cast-in fastener of the second wall section.