AU2009222609A1 - Construction of Reinforced Concrete Tanks - Google Patents

Description

Regulation 3.2 Australian Patents Act 1990 - Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title "Construction of Reinforced Concrete Tanks" The following statement is a full description of this invention, including the best method of performing it known to me/us: Q:\OPER\MRF\209\30826454 267.doc - 6110109 P.\OPER\MRF\Specificiirkd2009\COMPLETE30826454 omplete246 do-6/10/2009 Construction of Reinforced Concrete Tanks The present invention relates to construction of reinforced concrete tanks. More particularly, the invention relates to a reinforced tank panel which can be joined to a 5 plurality of joined like panels to form the tank, a tank formed by those panels, and an associated method of constructing a tank. In recent years, particularly since the terrorist attacks in the United States on 11 September 2001, insurance companies have required, in order to insure a building and 10 its contents, a guarantee of water supply to the building in the event of a fire. Consequently, installation of large water tanks, particularly beside large warehouses has become common. Moreover, severe bush/forest fires, particularly those which affected Victoria, Australia on 15 7 February 2009, underline a need for a plentiful and widespread supply of water throughout regions which are vulnerable to such fires. Water tanks are commonly made from steel, and in particular very thin steel panels, which are relatively lightweight and transportable. Some steel tanks are fitted with liners or 20 membranes, which may be made from any one of a number of materials, including PVC, polyethylene and polypropylene. Steel tanks provided with such liners have a number of disadvantages. Firstly, the liners have only a limited life and eventually need to be replaced, commonly every 10 years or so. Also, the nature of the liner is often such that it will wear due to water movement or be otherwise damaged, and can come loose, 25 particularly under suction of the water when drawn from the tank, and block the output from the tank, potentially resulting in catastrophic failure and an associated loss of supply from the tank, possibly in the case of a fire. Moreover, a fire which is close to the tank can cause the tank and/or liner to fail. 30 Steel tanks are also vulnerable to malicious damage and deliberate or accidental impact damage. They are also vulnerable to corrosion in particular environments, particularly P 3OPER\MRF\Specifietio,209\COMPLETEM-1826454 compl-e246.doc.6/10/200J9 -2 those in which they are in contact with soil, and in wet climates. Whilst many of the drawbacks of lined steel tanks can be avoided by instead using concrete tanks, which are strong and resistant to fire and malicious damage, and the 5 elements generally, such tanks present their own limitations and drawbacks. In particular, concrete is heavy and presents transportation challenges and limitations. Generally speaking, reinforced concrete tanks are either preformed and transported to site, in which case they can only be made in small sizes, or cast on site using a continuous mould - an expensive, complicated and time-consuming process. Whilst a reinforced concrete tank 10 may be assembled from pre-formed panels, which may be transported separately and joined together on-site, tanks so formed are rare because of complexities and expense associated with tensioning the panels after they are joined. According to a first aspect of the invention, there is provided a tank wall panel formed 15 from reinforced concrete, the panel having top and bottom ends and first and second side edges extending between the ends, the panel including a plurality of reinforcing rods extending between the first and second side edges at spaced apart positions between the ends, first and second ends of the rods being disposed adjacent the first and second edges respectively, the panel being provided with coupling means configured to couple the first 20 ends of the rods with the second ends of the rods of an adjacent like panel so as to tension the rods, thereby effecting tight abutment between the first edge of said tank wall panel and the second edge of the like panel. Preferably, the coupling means comprises a plurality of couplings, each coupling engaging 25 the first end of a respective rod of said tank wall panel and being configured for engagement with the second end of a corresponding rod of the like panel. Preferably, each coupling is configured for adjustable threaded engagement with the second end of the respective corresponding rod. Preferably, each coupling is further 30 configured for adjustable threaded engagement with the second end of the respective corresponding rod.

P:\OPER\MRF\Speiriaonks2009\COMPLETE\30026454 complex 246 doc-6/10/2009 -3 Preferably, each coupling comprises a connector and fastening means for fastening the ends thereto. Preferably, the second ends are threaded and the fastening means includes a threaded element engageable with the respective second end to fasten it to the connector. Preferably, the first ends are threaded and the fastening means further includes a further 5 threaded element which engages the respective first end to fasten it to the connector. Preferably, each connector is countersunk in a wall of the panel. Preferably, each connector is cast into the wall. 10 Preferably, each connector comprises laterally inner and outer end walls which are configured to receive the rod ends, and is formed at an outer end with an opening between said end walls providing access to the fastening means. Preferably, each connector further comprises top and bottom walls extending between said end walls, and the opening is located between the top and bottom walls. Preferably, each connector further comprises a 15 wall located at an inner end thereof. Preferably, each connector is configured in the form of an outwardly open box. Preferably, the coupling means is configured to be able to be able to receive a filling material to cover the rod ends received thereby. Preferably, the panels are configured such 20 that the filling material can be applied thereto to cover the coupling means. Preferably, the opening is disposed on an outer side of the panel. Preferably, the panel has an outwardly convex profile, whereby the panel and a plurality of 25 like panels are interconnectable to form a cylindrical tank wall. Preferably, the panel comprises at least one tie at its lower end, the tie being configured to be cast into a base of the tank to tie the panel to the base. 30 Preferably, at least one of the edges is profiled such that it defines with the adjacent edge abutting therewith a channel into which a sealant can be received. Preferably, the or each P OPER\MRF\Specrcation\20 XCOMPLETE0.10826454 complex 246 doc-6/11/20X9 -4 edge is profiled such that the channel is disposed on an inside face of the tank wall. According to a second aspect of the present invention, there is provided a tank having a wall comprising a plurality of panels as described above coupled together. 5 According to a third aspect of the present invention, there is provided a method of manufacturing a tank, comprising: coupling together a plurality of tank wall panels as described above; and forming a base at the lower ends of the panels. 10 Preferably, the method further comprises applying adhesive to the first edge of each panel and/or the second edge of the respective like panel before effecting the abutment therebetween. 15 Preferably, at least one of the edges is profiled such that it defines with the adjacent edge abutting therewith a channel, and the method further comprises applying sealant to the channels. Preferably, the method further comprises applying a sealing composition to inner faces of 20 the panels. Preferably, the method further comprises forming an input into and/or output from the tank in said base. 25 Preferably, the method further comprises applying a filling material to the coupled panels to cover the rod ends. Preferably, method further comprises applying the filling material to the coupled panels to cover the coupling means. Preferably, the filling material is fireproof. 30 It will be appreciated that abutment between the adjacent first and second edges can be direct, involving contact between those edges, or indirect - for example, in the case of a P:\OPER\MRF\Specircation209\COMPLETEUI)826434complete246.doc-6/1U/2009 -5 seal which could be arranged between the first and second edges. According to a fourth aspect of the present invention, there is provided a method of manufacturing a reinforced concrete tank wall panel as described above, including: 5 arranging, in a mould cavity, the connectors and the plurality of reinforcing rods such that the rods extend between first and second side walls of the cavity at spaced apart positions between opposed end walls of the cavity and the first ends of the rods are received by the connectors adjacent the first side wall, second ends of the rods being disposed adjacent the second side wall; and 10 filling the cavity with concrete and effecting curing of the concrete to form the panel. Preferably, the rods are arranged in the cavity such that their second ends are received by holes provided in the second side wall. 15 Preferably, the method further includes fixing the connectors to the first side wall prior to filling the cavity with concrete. Preferably, the laterally outer end walls of the connectors are bolted to the first side wall. Preferably, the laterally outer end walls and/or first side wall are/is provided with tapered holes which receive tapered nuts and/or tapered bolt 20 heads to locate the connectors in the cavity. The present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 25 Figure 1 is a perspective view of the reinforced concrete tank wall panel laid on its side; Figure 2 is a perspective elevation view of a closed tank wall formed from a plurality of joined panels according to the preferred embodiment; Figure 3 is a detailed view of one of a plurality of couplings in the panel which 30 couple it to an adjacent panel; Figure 4 is a cross-sectional view of the coupling shown in Figure 3; P:OPER\MRF\Speciicatios\2(0)9\COMPLETEU0826454 complete 246 doc-6/10/2009 -6 Figures 5 and 6 are views of a mould used to form the panel; Figures 7 to 14 are perspective views showing sequential stages of manufacture of the panel; and Figure 15 is a perspective view of a tank incorporating the wall shown in Figure 2. 5 A reinforced concrete tank panel I according to a preferred embodiment of the invention is illustrated in Figure 1. The panel I comprises a reinforced concrete wall 3 having a transverse cross-sectional configuration conforming to an arc of a circle whereby a plurality of joined panels 1 will form the wall 100 of a cylindrical tank 150 (see Figures 2 10 and 15). The panel I has a thickness of 180mm which affords the tank wall 100 a 4-hour fire rating. In the present embodiments, the wall 100 is formed from 12 panels 1. The panel 1 has a top end 5, bottom end 7 and first 9 and second I1 side edges. The height of the panel 1 (i.e. the difference between ends 5 and 7 is 6 metres and the arc length 15 between edges 9 and 11 is approximately 2.4 metres, these dimensions being the length and width dimensions of a standard mesh sheet 20 incorporated into the panel 1 (see Figure 8). The panel I further comprises a plurality of reinforcing rods 13, each 2.3m in length, 20 extending internally between the first 9 and second I1 side edges at spaced apart positions between the lower 7 and upper 5 ends. The rods 13 in a lower portion of the panel I are arranged more closely together than those in an upper portion of the panel I to ensure greater strength in a lower portion of the tank wall, where hydrostatic pressures will be greatest. Countersunk into the panel through its outer face adjacent edge 9 are several 25 connectors 15, one of which can be seen in cross-section in Figure 4, which receive respective first ends 12 of the rods 13. Second ends 14 of the rods 13 project from edge 11 to be receivable by a respective connector 15 when edge 11 is brought against an edge 9 of a like panel 1. 30 With reference to Figures 3 and 4, each connector 15 is fabricated from a short length of rectangular hollow section steel 16 and a plate 17 welded to the open inner end thereof, the P:\OPER\MRF\Specircations\29\COMPLE"m'\30326454 complete 246.doc-6/11/2fO)9 -7 connector 15 thus taking the form of a rectangular box having an opening 18 at its outer end. The connector 15 further comprises reinforcing plates 19 fixed to the end walls of the section 16. Holes 16A and 16B are provided through the end wall 16 and reinforcing plates 19 at the laterally outer and inner ends, respectively, of the connector 15, through 5 which first end 12 and a second 14 of a corresponding rod 13 respectively are receivable. The ends 12, 14 are threaded so as to be fastenable to the end walls of the respective connectors 15 by nuts 21, each connector 15 and pair of nuts 21 defining a coupling for joining the panel 1 to an adjacent panel 1. 10 The panel I further includes a plurality of longitudinal reinforcing rods 22 arranged at spaced apart positions between edges 9 and 11 and extending internally between the ends 7 and 5. Lower ends 23 of the rods 22 are formed with bends defining ties 24 which are receivable into a tank base 90 (see Figure 15) which is cast after formation of the cylindrical tank wall 100, thereby tying the wall 100 to the base 90. 15 The panel 1 further comprises a pair of ground-engageable legs 27 cast into the wall 3 and extending from lower end 7 to support the tank wall 100 and ties 24 clear of the ground (see Figures 2 and 3) to allow for pouring of the base. 20 The method of manufacturing the panel I and forming the tank 150 from a plurality of panels I will now be described with reference to the drawings. The panel I is cast in a mould 30, exploded and assembled views of which are shown in Figures 5 and 6 respectively. The mould 30 comprises a base frame 31 and a mould base 25 piece 32 which is received on the frame 31, the piece 32 comprising a curved steel sheet an upper surface 33 of which forms the floor of the mould cavity 60 and a plurality of stiffeners 34 shaped in the form of circular segments and fixed to the underside of the plate 33 to support it. 30 The assembly 30 further comprises a pair of channel members 36 which are securable to opposite sides of the frame 31. Specifically, the channel members 36 attach to inclined P %OPER\MARF\Specificaions\200COMPLET-30326454compleoe246 doc4/10/20M9 -8 arms 37 arranged along each side of the frame 31, each arm being formed with a slot 38. The channel members 36 are bolted to the arms through the slots 38 (the function of which will be described later) to define side walls of the mould cavity 60. 5 The frame 31 further comprises end assemblies 40 and 50, which define the end walls 41 and 51 respectively of the mould. End assembly 40 comprises a curved plate 41 which defines an end wall of the mould cavity 60 corresponding to the top end 5 of the panel 1, and four legs 42 to which the plate 41 is mounted and which bolt to an end of the frame 31 to locate the plate 41 against the plate 33. End assembly 50 similarly comprises a curved 10 plate 51, which defines an end wall of the cavity 60 corresponding to the bottom end 7 of the panel 1, and legs 52, which bolt to the other end of the frame 31, but the plate 51 is provided in two parts which are separately fixed to the legs 52, namely a top part 51A removably bolted to the legs 52 and a bottom part 51B. The abutting edges of the parts 51A and 51B are profiled with corresponding semicircular cutouts which, when the 15 parts 51 A and 51 B are abutting define holes which accommodate the rods 22 and stands 27 (see Figure 11). The end assembly 40 may be modified slightly such that the position of plate 41 along the channel members 36, and thus the length of the mould cavity 60, is variable, allowing for panels to be manufactured in different lengths. 20 Side edge portions 35 of the plate 33 are angled upwardly slightly from the curved plate surface to form bevels 4 (see Figure 1 (inset) and Figure 4) along the inner ends of edges 9 and 11, the purpose of which will be described later. The assembled mould 30 is shown in Figure 6. The channel members 36 are positioned 25 such that the bolts securing them to arms 37 are located at laterally inner ends of the slots 38 whereby the channel webs meet the side edges of the plate 33 to define side walls of the mould cavity 60. Each web is provided with through holes therealong which receive ends of the rods 13, as will be described further later. 30 With the mould 30 assembled, though with plate piece 51A removed, fabrication of the panel 1 commences with the longitudinal rods 22 and stands 27 being arranged in the P OPER\MRF\Specifcatons\2m9\COMPLE 30826454complete 246 do-6/10/2009 -9 cavity 60 on chairs 62 which space them above the cavity floor, the rod ends 23 and stands 27 being received in the appropriate semicircular cutouts formed at the top edge of plate piece 51B. 5 Next, plate piece 51A is secured to legs 52 to lock the ends 23 and stands 27 in position in plate 51. The reinforcing mesh 20, which is rolled to have the same curvature as the cavity 60, is then lowered into the cavity 60 to rest on the rods 22 and stands 27, then secured to the rods 22 using short lengths of wire. Referring to Figures II to 13, the connectors 15 are then bolted to the web of one of the channel members 36 so as to be 10 located in position. To ensure that the connectors 15 are accurately located, the holes in the channel web and corresponding holes 16A in the laterally outer end walls of the connectors 15 are tapered and receive a correspondingly tapered nut 70 and a bolt 71 having a correspondingly tapered head 72 respectively, whereby screwing of the nut 70 and bolt 71 together forces the connector 15 to locate in the correct position against the 15 web (see Figure 13). Following location of the connectors 15, the rods 13, which are also pre-curved, are then positioned in the cavity 60 by feeding their first ends 12 through the holes 16B in the laterally inner end walls of the connectors 15 and feeding their second ends 14 through the 20 holes in the web of the channel member 36 defining the opposite side wall of the cavity 60. Nuts 21 are then secured to the ends 12 to couple them to the connectors 15. Next, cement is poured into the cavity 60 until it is full. A curved screed is used to afford the upper surface of the cement a curved profile corresponding to the curved profile of 25 plate 32, the cement being sufficiently thick that it retains that profile during setting. As will be clear from Figure 14, the connectors 15 are sized such that their front ends are substantially flush with the outer face of the wall 3 when cast. After the concrete has set, the connectors 15 are unbolted from the channel web 36 to 30 which they are fixed. The bolts securing the channel members 36 to the arms 37 are then slackened and the channel members 36 thus retracted along the slots 38. Plate piece 5lA is P:\OPERMRF\Specificatiom2009\COMPLEE0826454 complete 246doc-6/10/2009 -10 then unbolted from the legs 52 and removed, whereupon the panel 1 can be lifted from the mould 30. Because the connectors 15 were secured to the web of one of channels 36 during casting, and that web forms one of the side walls of the mould cavity 60, the laterally outer end walls of the connectors 15 are countersunk in the edge 9 and define part 5 of the end wall of that edge. Formation of the tank 150 using panels I commences with arranging two panels I upright and such that the rod ends 14 of one panel are received in the holes 16A of the connectors 15 of the other panel. Concrete adhesive 80 (see Figure 4), such as a high strength 10 construction adhesive (which may or may not be water-based), is applied to the mating faces 8, 10 of the adjacent edges, before they are brought adjacent each other. The nuts 21 are then screwed onto ends 14 (the nuts 21 already being secured to ends 12) and tightened to bring the faces 8, 10 into tight abutment and to tension the rods 13 effecting that abutment. The nuts 21 on the ends 12 are also tightened to tension the rods 13 received 15 through the laterally inner end walls of the connectors 17. These steps are repeated with successive further panels I until cylindrical tank wall 100 is formed. The configuration of each panel 1 is such that tightening of the nuts 21 effects tensioning of the rods 13 substantially throughout their lengths. 20 Next, internal V-shaped grooves formed by the adjacent bevels 4 are filled with silicone sealant 82, and the tank base 90 with appropriate formwork in place, is poured and allowed to set. The appropriate tank outlet and associated plumbing can, if appropriate, be incorporated into the base 90. Alternatively, it can be incorporated into one of the panels I during casting. 25 Also, the connectors 15 are completely filled with a filler composition 88, preferably fireproof non-shrinking grout 88, which covers the rod ends. The composition 88 is applied such that it also covers the outer end/perimeter edge of each connector 15. Advantageously, the filler composition provides protection against removal of the bolt 30 heads (which are submerged therein), fire damage to the couplings and rod ends (ensuring a four-hour fire rating), corrosion and damage generally.

P 0PER\MRF\Specincaions\2)9\COMPLE l26454 compIcle 246.doc-61f2M9 - 11 The entire interior surface of the tank, comprising the floor (defined by the base 90) and inner wall surfaces, is then sprayed with a polyurethane lining composition 84 which bonds to the concrete. The composition 84 may, advantageously, be potable water certified, whereby contamination of water in tank by the resulting lining on the walls and 5 floor may be eliminated. The composition 84 is preferably compliant with standard AS/NZ4858:2004 ("Wet Area Membranes"). Advantageously, the lining, because it bonds to the concrete, is not prone to separation from the tank wall and floor in the way a steel tank liner may be. The inner faces of the panels 1 may alternatively be sprayed with lining 84 before the panels I are coupled. 10 The panel I offers a number of significant advantages. In particular, it enables a very large tank to be constructed (the capacity of the tank in the case of the present embodiment being 435KL) in a simple, rapid and reliable manner. Moreover, the panels I are relatively easy to handle and transport, three such panels at a time being transportable on one truck. 15 The panels 1, which are pre-stackable, can be transported in a "flat deck" manner by rail. Owing to the ease of handling and transporting the panels 1, a tank for a given area can often be located exactly at the optimal position within that area, optimising the utility of the tank, particularly in fire fighting applications, for which the tank, in being formed from concrete and thus having a high fire rating, will be ideally suited. For example, the tank 20 may be strategically located so as to receive run-off water from hills or other natural land features. The tank, unlike steel tanks, is substantially inert to climatic and environmental conditions. In addition, because tensioning in the panels is effected locally (at the connections between 25 adjacent panels), the requisite circumferential tension in the tank wall reinforcement can be established in a simple, rapid and reliable manner, there being no need for complicated, expensive and potentially unreliable post-tensioning procedures. It will be appreciated that the panel in alternative embodiments can have different shapes 30 and, in particular, alternative transverse cross-sectional configurations (including straight configurations), and that it may be a different number of panels according to alternative P:\OPER\MRF\Speci~na\2tXICOMPL.ETE\30826454 complee246.doc6/1/20i9 - 12 embodiments of the invention which form a tank. While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of 5 limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments. 10 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 15 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (24)

1. A tank wall panel formed from reinforced concrete, the panel having top and bottom ends and first and second side edges extending between the ends, the panel 5 including a plurality of reinforcing rods extending between the first and second side edges at spaced apart positions between the ends, first and second ends of the rods being disposed adjacent the first and second edges respectively, the panel being provided with coupling means configured to couple the first ends of the rods with the second ends of the rods of an adjacent like panel so as to tension the rods, thereby effecting tight abutment 10 between the first edge of said tank wall panel and the second edge of the like panel.

2. A panel according to claim 1, wherein the coupling means comprises a plurality of couplings, each coupling engaging the first end of a respective rod of said tank wall panel and being configured for engagement with the second end of a corresponding rod of the 15 like panel.

3. A panel according to claim 2, wherein each coupling is configured for adjustable threaded engagement with the second end of the respective corresponding rod. 20

4. A panel according to claim 2 or 3, wherein each coupling is configured for adjustable threaded engagement with the second end of the respective corresponding rod.

5. A panel according to any one of claims 2 to 4, wherein each coupling comprises a connector and fastening means for fastening the ends thereto. 25

6. A panel according to claim 5, wherein the second ends are threaded and the fastening means includes a threaded element engageable with the respective second end to fasten it to the connector. 30

7. A panel according to claim 6, wherein the first ends are threaded and the fastening means further includes a threaded element which engages the respective first end to fasten P-\OPER\MRF\SpecifkationOM9\COMPLETE1)826454complee246 do-.6/1)/20(9 - 14 it to the connector.

8. A panel according to any one of claims 5 to 7, wherein each connector is countersunk in a wall of the panel. 5

9. A panel according to any one of claims 5 to 8, wherein each connector comprises laterally inner and outer end walls which are configured to receive the rod ends, and is formed at an outer end with an opening between said end walls providing access to the fastening means. 10

10. A panel according to claim 9, wherein each connector is configured in the form of an outwardly open box.

11. A panel according to any one of the preceding claims, the panel having an 15 outwardly convex profile.

12. A panel according to claim 11, wherein the outwardly convex profile is such that the panel and a plurality of like panels are interconnectable to form a cylindrical tank wall. 20

13. A panel according to claim 12, wherein at least one of the edges is profiled such that it defines with the adjacent edge abutting therewith a channel into which a sealant can be received.

14. A panel according to any one of the preceding claims, wherein the coupling means 25 is configured to be able to receive a filling material to cover the rod ends received thereby.

15. A panel according to claim 14, wherein the panels are configured such that the filling material can be applied thereto to cover the coupling means. 30

16. A panel substantially as hereinbefore described with reference to the accompanying drawings. P30PER\MRF\Specxatons\20m9COMPLETB30826454 complete 246 doc.610/20)9 - 15

17. A tank having a wall comprising a plurality of panels according to any one of the preceding claims coupled together.

18. A method of manufacturing a tank, comprising: 5 coupling together a plurality of tank wall panels according to any one of claims I to 14; and forming a base at the lower ends of the panels.

19. A method according to claim 18, further comprising applying a filling material to 10 the coupled panels to cover the rod ends.

20. A method according to claim 19, further comprising applying the filling material to the coupled panels to cover the coupling means. 15

21. A method of manufacturing a reinforced concrete tank wall panel according to claim 1, including: arranging, in a mould cavity, the connectors and the plurality of reinforcing rods such that the rods extend between first and second side walls of the cavity at spaced apart positions between opposed end walls of the cavity and the first ends of the rods are 20 received by the connectors adjacent the first side wall, second ends of the rods being disposed adjacent the second side wall; and filling the cavity with concrete and effecting curing of the concrete to form the panel. 25

22. A method according to claim 21, further including bolting laterally outer ends of the connectors to the first side wall prior to filling of the cavity with concrete to fix the connectors in the cavity.

23. A method according to claim 22, wherein the laterally outer ends and/or first side 30 wall are/is provided with tapered holes which receive tapered nuts and/or tapered bolt heads to locate the connectors in position relative to a wall of the panel formed by the P:OPER\MR\Specifations2O9COMPLETEt30826454 complete 246.doc./10/2009 - 16 concrete.

24. A method of manufacturing a reinforced concrete tank wall panel, substantially as hereinbefore described with reference to the accompanying drawings.