Pre-cast pre-stressed concrete tank comprising temporary opening

Abstract

To provide a method of manufacturing a pre-cast pre-stressed concrete tank for storing liquefied gas.SOLUTION: A manufacturing method according to the present invention includes providing first and second pre-cast outer-wall panels, defining an access exit / entrance to provide a temporary opening frame including a plurality of clamps, assembling the first and second pre-cast outer-wall panels and the temporary opening frame together to provide a secondary tank, assembling a primary tank assembly within the secondary tank, winding a first-phase wire wrap around the secondary tank, setting up the temporary opening frame with temporary backing before winding the first-phase wire wrap, and clamping the first-phase wire wrap on the temporary opening frame with the clamps.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to concrete tanks for storing liquefied gas, and more particularly to a method for manufacturing precast prestressed concrete tanks for storing liquefied gas. [Background technology]

[0002] Many gases, such as methane, nitrogen, and natural gas, are stored at temperatures well below normal ambient temperatures, allowing them to remain in a liquid state. This allows for the storage of large volumes of gas in what may be a limited space. These cryogenic liquefied gases are typically not maintained at high pressures, but rather at near atmospheric pressure or at relatively low pressures. Thus, storage tanks or facilities do not need to be designed for large internal pressures.

[0003] Precast prestressed concrete tanks are well known for the storage of liquefied gases, for example, as described in U.S. Patent Nos. 3,092,933, 3,633,328, and 3,488,972, all to Closner et al. and assigned to Preload Corp. Typically, a precast prestressed concrete tank has an inner wall defining a primary tank and an outer wall defining a secondary tank. The outer wall is prestressed by applying wire windings around the outer wall under tension. The inner wall is typically constructed of 9% nickel steel or some other type of steel suitable for use at cryogenic temperatures. In some cases, the inner tank may also be precast prestressed concrete.

[0004] During the construction of precast prestressed concrete tanks, when the outer wall is constructed first, the inner wall needs to be inserted through an opening in the top of the tank or by tunneling under the foundation to insert the inner wall from below the tank. However, these conventional construction methods of precast prestressed concrete tanks are complicated and undesirable.

[0005] There is a continuing need for precast prestressed concrete tanks and methods that facilitate the construction of a primary tank within a secondary tank. Desirably, the precast prestressed concrete tanks and methods would allow for the construction of an interior wall after the exterior wall has been erected without requiring insertion through the top of or by tunneling under the exterior wall. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 3,092,933 [Patent Document 2] U.S. Patent No. 3,633,328 [Patent Document 3] U.S. Patent No. 3,488,972 Summary of the Invention

[0007] Consistent with the present disclosure, a precast prestressed concrete tank and method have surprisingly been discovered that facilitates construction of a primary inner tank within a secondary outer tank and allows for construction of the inner wall after the outer wall has been erected without requiring insertion through the top of the outer wall or by tunneling under the outer wall.

[0008] In one embodiment, the precast prestressed concrete tank includes a primary tank with an interior wall and a secondary tank with an exterior wall (precast prestressed concrete) and wire windings. The primary tank is positioned inside the secondary tank. The secondary tank has a plurality of first precast exterior wall panels and a temporary opening frame. During assembly of the precast prestressed concrete tank, the temporary opening frame defines an access doorway. The temporary opening frame is placed on a foundation base slab and sealed.

[0009] In another embodiment, the precast prestressed concrete tank includes a primary tank having an inner wall and a secondary tank having an outer wall with wire windings. The primary tank is disposed inside the secondary tank. The secondary tank includes a plurality of first precast exterior wall panels, at least one second precast exterior wall panel, and a temporary opening frame disposed on a foundation base slab. The temporary opening frame has a base section, a pair of column sections, and a header beam section. The temporary opening frame has two second precast exterior wall panels disposed between the pair of first precast exterior wall panels and disposed on top of the header beam section. Each of the second precast exterior wall panels has a height that is less than a height of the first precast exterior wall panels. The temporary opening frame has a plurality of clamps. The clamps secure the first wire windings to the temporary opening frame. The temporary opening frame is sealed with an inner plate, a first layer of shotcrete, an outer plate, and a second layer of shotcrete, and an additional phase of wire windings is further wound thereon.

[0010] In a further embodiment, a method for manufacturing a precast prestressed concrete tank includes providing a plurality of first precast exterior wall panels and at least one second precast exterior wall panel. The at least one second precast exterior wall panel is shorter than each of the first precast exterior wall panels. A temporary opening frame is also provided. The temporary opening frame defines an access doorway and includes a plurality of clamps. The first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame are then assembled to provide a secondary tank assembly. The access doorway of the temporary opening frame provides access to an interior of the secondary tank assembly. A single-phase wire winding is then wrapped around at least a portion of the second tank assembly. The wire winding is clamped over the temporary opening frame with a clamp. The wire winding over the access doorway of the temporary opening frame is then cut, and a remaining portion of the wire winding remains held in place under tension by the clamp. The primary tank assembly is then assembled into the secondary tank assembly by delivery of components through the access doorway, which is then sealed in the temporary opening frame access doorway.

[0011] Further scope of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0012] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. The above, as well as other advantages of the present disclosure, will become readily apparent to those skilled in the art from the following detailed description, especially when considered in light of the drawings described below. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a front perspective view of a precast prestressed concrete tank according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing the temporary opening frame. [Diagram 3] FIG. 2 is a front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing the temporary opening frame and a plurality of first and second precast exterior wall panels. [Figure 4] FIG. 2 is a front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing a temporary opening frame with a plurality of clamps, a plurality of first and second precast exterior wall panels, and a first phase wire winding. [Diagram 5] FIG. 2 is an exploded front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing a plurality of clamps, a plurality of first and second precast exterior wall panels, the dome, and a temporary opening frame with a first phase wire winding, the wire winding being cut at the temporary opening frame and the free ends of the cut wire winding being secured by the clamps. [Figure 6A] FIG. 6 is a front view of one of the clamps shown in FIGS. 4 and 5. [Figure 6B] FIG. 6B is a side view of the clamp shown in FIG. 6A. [Figure 7] FIG. 2 is a front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing a plurality of clamps, a plurality of first and second precast exterior wall panels, a dome, and a temporary opening frame with a first phase wire winding, the first phase wire winding being cut at the temporary opening frame, the free ends of the cut wire winding being secured by clamps, a ramp being installed at the temporary opening, and the primary tank inner wall being installed through the opening in the temporary opening frame. [Figure 8] FIG. 2 is a front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing the temporary opening frame, a plurality of first and second precast exterior wall panels, a plurality of clamps, a dome, and a plate assembly sealing the opening in the temporary opening frame. [Figure 9] FIG. 9 is a fragmentary cross-sectional side view of the inner wall and plate assembly of the primary tank taken along section line 9--9 of FIG. [Figure 10] FIG. 2 is a front perspective view of the precast prestressed concrete tank shown in FIG. 1 in an assembled state, showing a temporary opening frame with a second phase wire winding disposed over the plurality of clamps, the plurality of first and second precast exterior wall panels, the dome, and the plate assembly. [Figure 11] 11 is a flow chart illustrating a method for manufacturing the precast prestressed concrete tank shown in FIGS. 1-10 according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The following detailed description and the accompanying drawings describe and illustrate various exemplary embodiments of the present disclosure. The description and drawings serve to enable one of ordinary skill in the art to make and use the present disclosure, and are not intended to limit the scope of the disclosure in any way.

[0015] 1-11 show a precast prestressed concrete tank 2 with a temporary opening frame 10 according to various embodiments of the present disclosure, and a method 100 for manufacturing the precast prestressed concrete tank 2. The method 100 for assembling the precast prestressed concrete tank 2 is further illustrated in FIGS. 2-10, as described below.

[0016] As shown in Figures 1, 4-5, and 7-9, tank 2 includes a primary tank 4 and a secondary tank 6. Primary tank 4 is constructed inside secondary tank 6. Primary tank has an inner wall (identified as "22" in Figure 7). Secondary tank 6 has an outer wall (identified as "32" in Figures 4-5). With reference to Figures 2-4, tank 2 further includes a base 24, further described herein, upon which inner wall 22 and outer wall 32 are disposed.

[0017] In the embodiments shown in Figures 1-5, 7-8, and 10, the tank 2 has a cylindrical shape, however, other shapes for the tank 2 are contemplated and may be selected by one of ordinary skill in the art within the scope of the present disclosure.

[0018] As shown in Figures 2-3, the secondary tank 6 includes a plurality of first precast exterior wall panels 8, a temporary opening frame 10, at least one second precast exterior wall panel 12, and a dome 15. The at least one second precast exterior wall panel 12 may include, for example, a pair of second precast exterior wall panels 12 as shown in Figure 3. However, any other number of at least one second precast exterior wall panel 12 may be used.

[0019] The first precast exterior wall panel 8 and the at least one second precast exterior wall panel 12 may be fabricated from steel bar reinforced concrete, as a non-limiting example. Other suitable materials and means for manufacturing the precast wall panels 8, 12 may also be selected as desired.

[0020] 3, the at least one second precast exterior wall panel 12 may have a height (H2) that is less than the height (H1) of the first precast exterior wall panel 8. This difference between the heights H1 and H2 allows the at least one second precast exterior wall panel 12 to rest on the temporary opening frame 10 while maintaining the upper edges of both the first precast exterior wall panel 8 and the at least one second precast exterior wall panel 12 in the same plane or substantially in the same plane. This further allows a dome 14 to be placed on top of the secondary tank 6 and secured to the upper edges of both the first precast exterior wall panel 8 and the at least one second precast exterior wall panel 12, as shown, for example, in FIG.

[0021] In one particular embodiment, each of the first precast exterior wall panel 8 and the at least one second precast exterior wall panel 12 may have a substantially rectangular side profile with a slightly arcuate cross-section across the width of the panel 8, 12. Advantageously, the curvature of the first precast exterior wall panel 8 and the at least one second precast exterior wall panel 12 allows a plurality of the first precast exterior wall panels 8 to form the cylindrical structure of the exterior wall 32 of the secondary tank 6, as illustrated in FIG. 3. The first precast exterior wall panel 8 may also have a plurality of weld plates (not shown) formed into the concrete on each side of the panels 8, 12. These weld plates allow the panels to be welded together when forming the secondary tank 6.

[0022] 2, the temporary opening frame 10 has a base section 14, a pair of column sections 16, and a header beam section 18. The temporary opening frame 10 defines a temporary opening or access doorway 20. The temporary opening frame 10 may be fabricated from 9% Ni steel. However, one skilled in the art may also select other suitable materials for the temporary opening frame 10 as needed.

[0023] In a particular embodiment, the temporary opening frame 10 has a base section 14, a pair of column sections 16, and a header beam section 18, each of which may have hollow channels (not shown) that may be filled with high strength grout during its construction. The high strength grout is configured to strengthen the temporary opening frame 10 and aid in integrating the temporary opening frame 10 with the panels 8, 12. In particular, the high strength grout may be a non-shrink, non-bleeding grout. The high strength grout may be selected to have a compressive strength at least equal to the compressive strength of the concrete used to fabricate the panels 8, 12 of the secondary tank 6.

[0024] As shown in FIG. 2, the temporary opening frame 10 may be fabricated integrally with the base 24 or may be securely fastened to the base 24 in some cases. In an exemplary embodiment, the base 24 includes the temporary opening frame 10, a sketch plate 26, a skirt plate 28, and a foundation base slab 30. The base section 14 of the temporary opening frame 10 may be integral with the skirt plate 28, for example. Other suitable means for connecting the temporary opening frame 10 to the base 24 of the tank 2, including fasteners and welds, may also be used within the scope of the present disclosure.

[0025] 2, the foundation base slab 30 may be a concrete slab. The foundation base slab 30 may have a thickness of about 5 feet, although other thicknesses are contemplated and may be used. The foundation base slab 30 may further have seismic base cables (not shown) and slide bearings (not shown) extending from the base slab 30 around its periphery. Those skilled in the art may also select other suitable construction parameters for the foundation base slab 30 as needed.

[0026] In particular, the sketch plates 26 may be fabricated from 9% Ni steel, although other suitable materials may be used. The sketch plates 26 may be welded together all around below the final exterior wall, and a stainless steel plate with a "mirror-8" finish is epoxied to the underside of the sketch plates 26 and rests on a plain bearing.

[0027] Similarly, the skirt plate 28 may be fabricated from 9% Ni steel or any other suitable material and welded together all around just outside the exterior wall 32 and just inside the seismic base cables of the foundation base slab 30. As disclosed, the base section 14 of the temporary opening frame 10 is fabricated integrally with the skirt plate 28. The skirt plate 28 is welded to the sketch plate 26 and forms a bottom corner of the exterior wall 32 of the secondary tank 6. The first precast exterior wall panel 8 is on the inside and abuts the bottom corner defined by the sketch plate 26 and the skirt plate 28.

[0028] 3, the temporary opening frame 10 can, by way of non-limiting example, replace two lower portions of a first precast exterior wall panel 8. It should also be appreciated that the temporary opening frame 10 may be sized to replace a single precast lower portion of a first precast exterior wall panel 8, or three or more precast lower portions of a first precast exterior wall panel 8, as desired.

[0029] During assembly, as also shown in Figure 3, one of the first precast exterior wall panels 8 is placed on a first side of the temporary opening frame 10 and another first precast exterior wall panel 8 is placed on a second side of the temporary opening frame 10. Then, at least one second precast exterior wall panel 12 is placed on the header beam section 18 of the temporary opening frame 10. This causes the temporary opening frame 10 to be completely surrounded by the first precast exterior wall panel 8, the at least one second precast exterior wall panel 12, and the base 24 of the tank 2.

[0030] 4, the post section 16 of the temporary opening frame 10 may have a number of clamps 34. The clamps 34 may be welded to the temporary opening frame 10, although other suitable means for securely fastening the clamps 34 to the post section 16 may be used.

[0031] In one non-limiting example, the clamps 34 may each have a pair of clamp bodies 40, for example, as shown in Figures 6A and 6B. The clamp bodies 40 may be connected by at least one threaded fastener 42 disposed through at least one threaded hole in the clamp bodies 40. Each of the clamp bodies 40 may also have an internal recess adapted to receive a wire winding (identified as "36" in Figure 4) and securely hold the wire winding 36 during operation. In the most particular example, each of the clamp bodies 40 is adapted to securely hold at least two of the wire windings 36, as shown in Figure 6B. One skilled in the art may also select other suitable clamping means for the clamps 34, as desired.

[0032] During assembly, as shown in FIG. 5, clamps 34 are used to secure the free ends of the first phase wire windings 36 to hold the wire windings 36 securely under tension even when the sections above the temporary openings 20 are cut and removed (as shown in FIGS. 5 and 7), as described further below.

[0033] 8, the temporary opening 20 is further sealed by a plate assembly 44 after cutting and removal of the section of the first phase wire windings 36 above the temporary opening 20 and after installation of the primary tank 4, as also described below. In a most particular embodiment, the plate assembly 44 can have four separate layers, including an inner plate 46, a first application of shotcrete 48, an outer plate 50, and a second application of shotcrete 52, as shown in FIG.

[0034] For example, the inner plate 46 may be fabricated from 9% Ni steel and is configured to seal the temporary opening 20. The inner plate 46 may be welded to the temporary opening frame 10. The inner plate 46 may also have a number of vertical supports and at least one horizontal support. The various supports leave hollow channels across the surface of the inner plate 46. The shotcrete 48 of the first application of the plate assembly 44 may then be placed into the hollow channel of the inner plate 46.

[0035] The outer plate 50 may be fabricated from 9% Ni steel and may also be configured to seal the temporary opening 20. The outer plate 50 is placed on the first application of shotcrete 48 and the temporary opening frame 10 where the outer plate 50 is welded to the temporary opening frame 10. The outer plate 50 may include two separate plates that rest approximately parallel to one another. The plates may be welded to both the temporary opening frame 10 and the horizontal support of the inner plate 46. A second application of shotcrete 52 is placed on the outer plate 50.

[0036] When the plate assembly 44 is installed to seal the temporary opening 20, the plate assembly is spaced further away from the inner wall 22 of the primary tank 4, as also shown in Figure 9. Advantageously, this particular construction of the plate assembly 44 has been found to be as strong or stronger than the remainder of the outer wall 32 associated with the secondary tank 6. Additionally, there may be an additional phase of wire windings 54 disposed above the plate assembly 44 and the sealed temporary opening 20, which further contributes to the desired strength of the plate assembly 44 during operation.

[0037] Following application of the second or additional phase wire windings 54, the additional phase wire windings may be further covered with shotcrete, thereby completing construction of the tank 2, as shown in FIG.

[0038] The present disclosure further includes a method 100 for manufacturing a precast prestressed concrete tank 2, as shown in FIG. 11 and described in more detail below.

[0039] The method 100 includes a first step 102 of providing a plurality of first precast exterior wall panels 8 and at least one second precast exterior wall panel 12. As described, the at least one second precast exterior wall panel 12 has a height (H2) that is less than the height (H1) of each of the first precast exterior wall panels 8. The temporary opening frame 10 can also have a height (H3), as shown in FIG. 3, the sum of the height (H2) and the height (H3) being approximately equal to the height (H1) in one particular embodiment. The panels 8, 12 may be provided by casting the panels 8, 12 from concrete with rebar inlay, as described above.

[0040] The second step 104 of the method 100 includes providing a temporary opening frame 10, as shown in FIG. 2. The temporary opening frame 10 defines an access doorway 20 and includes a plurality of clamps 34. More specifically, the second step 104 of the method 100 includes laying a concrete base slab 30 and installing seismic base cables and slide bearings. Next, a sketch plate 26 and a skirt plate 28 are installed on the foundation base slab 30. The installation of the skirt plate 28 includes the installation of the temporary opening frame 10. The hollow channels of the temporary opening frame 10 are then filled with the high strength grout described above.

[0041] Next, the method 100 includes a third step 106 of assembling the first precast exterior wall panel 8, at least one second precast exterior wall panel 12, and the temporary opening frame 10 to provide the exterior wall 32 of the secondary tank 6, as shown in Figure 3. It should be appreciated that when assembled under the third step 106, the temporary opening frame 10 provides access to the interior of the secondary tank 6 via the opening or access doorway 20.

[0042] This assembly under the third step 106 may include lifting the first precast exterior wall panel 8 with a crane and setting the first precast exterior wall panel 8 into position around a bottom corner of the base 24. One of the first precast exterior wall panels 8 is placed on a first side of the temporary opening frame 10 and another precast exterior wall panel 8 is placed on a second side of the temporary opening frame 10. Then, at least one second precast exterior wall panel 12 is placed on the header beam section 18 of the temporary opening frame 10.

[0043] The individual first precast exterior wall panel 8, second precast exterior wall panel 12, and temporary opening frame 10 are then welded together along the respective weld plates within the panels 8, 12. Shotcrete is then applied between the first precast exterior wall panel 8, second precast exterior wall panel 12, and the temporary opening frame 10. Shotcrete is then also applied to the entire exterior wall 32 defined by the assembled panels 8, 12.

[0044] A fourth step 108 of the method 100 includes filling the temporary openings with a temporary backing 38. Advantageously, the temporary backing 38 fills the temporary openings 20 during a subsequent step of the method 100, so that the secondary tank 6 can be prestressed with the first stage of the wire windings 36.

[0045] In particular, as illustrated in FIG. 4, the method 100 includes a fifth step 110 that includes wrapping a first phase wire winding 36 around at least a portion of the second tank assembly. The first phase wire winding 36 passes through a recess 41 in the clamp 34. For example, the winding 36 may wrap around the entire height H1 of the outer wall 32 of the secondary tank 6. One skilled in the art may also select other suitable heights to wrap the winding 36 around the second tank 6, as desired.

[0046] A sixth step 112 of the method 100 includes clamping the first phase wire winding 36 onto the temporary aperture frame 10 and the temporary backing 38. More specifically, the threaded fastener 42 of each of the clamps 34 may be tightened onto an associated one of the wire windings 36. When the threaded fastener 42 is disposed in the recess 41 between the clamp bodies 40, it draws the clamp bodies 40 toward each other causing a clamping action on the wire winding 36. Additionally, the wire winding 36 may be welded to the clamps 34 to further secure the wire winding 36 to the clamps 34.

[0047] The method 100 has a seventh step 114 which includes cutting the first phase wire winding 34 over the temporary opening 20 defined by the temporary opening frame 10. The remaining portion of the wire winding is held in place under tension by a clamp 34. As shown in FIG. 5, the clamp optionally secures a free end of the first phase wire winding 36 and allows the cut portion of the wire winding 36 to be removed so that the temporary backing 36 is exposed.

[0048] An eighth step 116 of the method 100 includes removing the temporary backing 36 from the temporary opening frame 10. Advantageously, after the first phase wire windings 36 are cut, the temporary backing 38 can be removed and the primary tank 4 can be assembled through the temporary opening 20. In particular, a preformed wall section of the primary tank 4 may be inserted through the opening or access doorway 20. The dome 15 is fabricated simultaneously with the installation of the secondary tank 6. The dome may also be installed on top of the secondary tank 6 before the primary tank 4 is constructed within the secondary tank 6, for example as shown in FIG. 5.

[0049] The method 100 further includes a ninth step 118 of assembling the primary tank 4 within the secondary tank 6 by delivery and installation of components through the temporary opening 20. To this end, a ramp 56 may be constructed adjacent the temporary opening 20 to facilitate movement of equipment and components for the primary tank 4 within the secondary tank 6. The primary tank 4 is then assembled within the secondary tank 6 by delivery of the necessary components through the access doorway 20.

[0050] Once the primary tank 4 is completed within the secondary tank 6, a tenth step 120 of the method 100 includes sealing the access hatch 20 of the temporary opening frame 10. The tenth step 120 of sealing the temporary opening 20 may specifically include welding an inner plate 46 to the temporary opening frame 10. The temporary opening is then further sealed with a first application of shotcrete 48. An outer plate 50 is then welded to the temporary opening frame 10 and the inner plate 46. A second application of shotcrete 52 is then applied over the outer plate 50. An exemplary construction of the plate assembly 44 is also described further above and shown in FIG. 9.

[0051] Next, the method 100 includes an eleventh step 122 of winding the additional phase wire winding 54 around the secondary tank 6, for example, as shown in FIG. 10. More specifically, the eleventh step 122 may include building from the exterior wall 32 with a mesh screen and further application of shotcrete. Next, the additional phase wire winding 54 is wound around the base of the secondary tank 6. More specifically, the additional phase wire winding 54 is wound around the base of the secondary tank 6 to at least the height (H3) of the temporary opening frame 10, as shown in FIG. 10. Subsequently, a final layer of shotcrete is applied to cover the additional phase wire winding 54. The ramp 56 is removed and an access staircase is installed along the exterior wall 32 of the secondary tank 6.

[0052] A twelfth step 124 of the method 100 may include applying a final layer of shotcrete to the secondary tank 6. Following this final application of shotcrete, the tank 2 is complete, as shown in FIG.

[0053] For purposes of illustrating the exemplary embodiments, various materials and dimensions have been described and shown in the drawings, however, it should be recognized that one skilled in the art may select other suitable materials and dimensions for the prestressed reinforced concrete tank 2 without departing from the scope of the present disclosure.

[0054] Advantageously, the temporary opening frame 10 of the precast prestressed concrete tank 2 and the associated manufacturing method facilitates the manufacture of the precast prestressed concrete tank 2 without requiring tunneling through the bottom of the secondary tank 6 or lifting components through the top of the secondary tank 6 during manufacture of the primary tank 4.

[0055] More specifically, it will be appreciated that the components forming the primary tank 4 may be inserted through the temporary opening 20, which is then sealed so that the secondary tank 6 may be completed following assembly of the primary tank 4.

[0056] From the foregoing description, those skilled in the art can easily ascertain the essential features of the present invention, and can make various changes and modifications to the present invention to adapt it to various usages and conditions without departing from the spirit and scope thereof.

Claims

1. 1. A method for manufacturing a precast prestressed concrete tank, comprising the steps of: providing a plurality of first precast exterior wall panels and at least one second precast exterior wall panel, the at least one second precast exterior wall panel having a height less than each of the first precast exterior wall panels; providing a temporary opening frame defining an access doorway and including a plurality of clamps; assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide a secondary tank, the temporary opening frame providing access to an interior of the secondary tank assembly; assembling a primary tank assembly into the secondary tank by delivery of components through the access port; winding a first phase wire winding around at least a portion of the secondary tank; and filling the temporary opening frame with a temporary backing prior to winding the first phase wire winding.

11. The method of claim 10, wherein the step of clamping the first phase wire winding onto the temporary opening frame with the clamps, each of the clamps including a pair of clamp bodies, each of the clamp bodies having a recess, the clamp bodies of each of the clamps being connected by at least one threaded fastener, and wherein winding the first phase wire winding further includes positioning the wire winding within the recesses of the clamps and tightening the clamps using the at least one threaded fastener.

2. 2. The method of claim 1, further comprising the step of cutting the first phase wire winding over the access doorway of the temporary opening frame after the step of clamping the first phase wire winding, such that a portion of the first phase wire winding over the access doorway is removed and a remaining portion of the first phase wire winding is held in place by the clamp.

3. 3. The method of claim 2, further comprising removing the temporary backing prior to assembling the primary tank assembly.

4. 2. The method of claim 1, wherein the step of providing a temporary opening frame further comprises the step of laying a base slab on a surface on which the precast prestressed concrete tank will be manufactured prior to the step of assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide the secondary tank.

5. The method of claim 4 , further comprising the step of installing a sketch plate and a skirt plate on the base slab, the temporary opening frame being constructed on an upper surface of the skirt plate.

6. 2. The method of claim 1, wherein the temporary opening frame has a base section, a pair of column sections, and a header section, the base section and the header section being connected at a distance by the pair of column sections, and wherein assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide the secondary tank further comprises positioning the at least one second precast exterior wall panel on the header section of the temporary opening frame.

7. 7. The method of claim 6, wherein the plurality of first precast exterior wall panels and the at least one second precast exterior wall panel have weld plates, and further comprising the step of joining the plurality of first precast exterior wall panels, the at least one second precast exterior wall panel, and the temporary opening frame by welding.

8. 8. The method of claim 7, further comprising applying shotcrete between the first precast exterior wall panel, the second precast exterior wall panel, and the temporary opening frame.

9. 9. The method of claim 8, further comprising the step of applying a spraycrete to the first precast exterior wall panel and the second precast exterior wall panel after the steps of assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame and providing the secondary tank.

10. 1. A method for manufacturing a precast prestressed concrete tank, comprising the steps of: providing a plurality of first precast exterior wall panels and at least one second precast exterior wall panel, the at least one second precast exterior wall panel having a height less than each of the first precast exterior wall panels; providing a temporary opening frame defining an access doorway and including a plurality of clamps; assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide a secondary tank, the temporary opening frame providing access to an interior of the secondary tank assembly; assembling a primary tank assembly into said secondary tank by delivery of components through an access port; sealing an access hatch of a temporary opening frame after the primary tank has been assembled into the secondary tank; after the step of sealing the access door, winding a second phase wire winding about the secondary tank assembly; applying shotcrete to the secondary tank assembly after the step of winding the second phase wire windings around the secondary tank assembly; 11. The method of claim 1, wherein the step of sealing the access doorway further comprises the step of welding an inner plate to the temporary opening frame prior to the step of winding the second phase wire winding around the secondary tank assembly.

11. 11. The method of claim 10, wherein sealing the access doorway further comprises applying shotcrete over the interior plate welded to the temporary opening frame prior to wrapping the second phase wire windings around the secondary tank assembly.

12. 12. The method of claim 11, wherein the step of sealing the access doorway further comprises the step of welding an outer panel to a temporary construction opening frame over a shotcrete surface of the inner panel prior to the step of wrapping the second phase wire windings around the secondary tank assembly.

13. 13. The method of claim 12, wherein sealing the access doorway further comprises applying shotcrete over the skin welded to the temporary opening frame prior to wrapping the second phase wire windings around the secondary tank assembly.

14. 1. A method for manufacturing a precast prestressed concrete tank, comprising the steps of: providing a plurality of first precast exterior wall panels and at least one second precast exterior wall panel, the at least one second precast exterior wall panel having a height less than each of the first precast exterior wall panels; providing a temporary opening frame defining an access doorway and including a plurality of clamps; assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide a secondary tank, the temporary opening frame providing access to an interior of the secondary tank assembly; delivering components through the access port and assembling a primary tank assembly within the secondary tank.

15. The method of claim 14 further comprising wrapping the first phase wire winding around at least a portion of the secondary tank.

16. 16. The method of claim 15, further comprising the step of filling the temporary opening frame with a temporary backing prior to the step of winding the first phase wire winding.

17. 17. The method of claim 16, including the step of clamping the first phase wire winding over the temporary opening frame with the clamp.

18. 15. The method of claim 14, wherein the step of providing a temporary opening frame further comprises the step of laying a base slab on a surface on which the precast prestressed concrete tank will be manufactured prior to the step of assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide the secondary tank.

19. 20. The method of claim 18, further comprising the step of installing a sketch plate and a skirt plate on the base slab, the temporary opening frame being constructed on an upper surface of the skirt plate.

20. 15. The method of claim 14, wherein the temporary opening frame has a base section, a pair of column sections, and a header section, the base section and the header section being connected at a distance by the pair of column sections, and wherein assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide the secondary tank further comprises positioning the at least one second precast exterior wall panel on the header section of the temporary opening frame.

21. 21. The method of claim 20, wherein the plurality of first precast exterior wall panels and the at least one second precast exterior wall panel have weld plates, and further comprising the step of joining the plurality of first precast exterior wall panels, the at least one second precast exterior wall panel, and the temporary opening frame together with welding.

22. 22. The method of claim 21, further comprising applying shotcrete between the first precast exterior wall panel, the second precast exterior wall panel, and the temporary opening frame.

23. 23. The method of claim 22, further comprising applying shotcrete to the first and second precast exterior wall panels after the steps of assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame and providing the secondary tank.

24. 15. The method of claim 14, further comprising the step of sealing an access hatch of the temporary opening frame after the primary tank is assembled within the secondary tank.

25. 25. The method of claim 24, further comprising the step of wrapping the second phase wire winding around the secondary tank assembly after the step of sealing the access door.

26. 26. The method of claim 25, further comprising the step of applying shotcrete to the secondary tank assembly after the step of winding the second phase wire windings around the secondary tank assembly.

27. 1. A method for manufacturing a precast prestressed concrete tank, comprising the steps of: providing a plurality of first precast exterior wall panels and at least one second precast exterior wall panel, the at least one second precast exterior wall panel having a height less than each of the first precast exterior wall panels; providing a temporary opening frame defining an access doorway and including a plurality of clamps; assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide a secondary tank, the temporary opening frame providing access to an interior of the secondary tank assembly; assembling a primary tank assembly into the secondary tank by delivery of components through the access port; winding a first phase wire winding around at least a portion of the secondary tank; Including, 11. The method of claim 1, wherein the step of providing a temporary opening frame further comprises the step of laying a base slab on a surface on which the precast prestressed concrete tank will be manufactured prior to the step of assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide the secondary tank.

28. 1. A method for manufacturing a precast prestressed concrete tank, comprising the steps of: providing a plurality of first precast exterior wall panels and at least one second precast exterior wall panel, the at least one second precast exterior wall panel having a height less than each of the first precast exterior wall panels; providing a temporary opening frame defining an access doorway and including a plurality of clamps; assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide a secondary tank, the temporary opening frame providing access to an interior of the secondary tank assembly; assembling a primary tank assembly into the secondary tank by delivery of parts through the access doorway; Including, The temporary opening frame has a base section, a pair of column sections, and a header section, and the base section and the header section are connected by the pair of column sections at an interval; assembling the first precast exterior wall panel, the at least one second precast exterior wall panel, and the temporary opening frame to provide the secondary tank comprises: positioning the at least one second precast exterior wall panel over a header section of the temporary opening frame; sealing an access hatch of the temporary opening frame after the primary tank is assembled within the secondary tank.

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