JP3149520U - Formwork bottom plate used in the construction of shaded concrete blocks - Google Patents

Abstract

An object of the present invention is to provide a bottom plate for a formwork used for the construction of a shaded concrete block capable of improving the workability of the shaded concrete block and shortening the construction period. SOLUTION: The bottom plate support 4 inserted from the opening of the top wall portion 6A of the cap concrete block 6 and attached to the sheet pile wall 2 and the lower end of the front wall portion 6B of the cap concrete block 6 toward the horizontal rear. The plurality of plate members 3A that can be mounted on the protruding bottom plate mounting protrusions 8 are provided, and the plurality of plate members 3A are provided with overlapping portions 11 at both ends, and each of these plate members 3A. In a state where the overlapping portions 11 are overlapped with each other, the concave-convex gap portion 9 between the sheet pile wall 2 and the inner surface of the front wall portion 6B is formed into a shape that can be closed. [Selection] Figure 3

Description

  The present invention relates to a bottom plate for a formwork used for construction of a cap concrete block constructed along a riverbank or a coast.

  2. Description of the Related Art Conventionally, a sheet pile wall formed by continuously placing a U-shaped steel sheet pile by engaging its claws as a quay wall such as a river or the sea, or a retaining wall on the ground has been used. And the cap concrete block is constructed in the upper part of this sheet pile wall for corrosion prevention or beautification as a structure.

  In addition, recently, the method for installing the shaded concrete block is mainly carried out by bringing the cast concrete block made of precast to the site for reasons such as high workability and a short construction period.

  Specifically, for example, a cap concrete block is installed on the top of the sheet pile wall via a height adjustment bolt, etc., and the top of the sheet pile wall is covered with the cap concrete block, and in front of the cap concrete block located on the water surface side. A bottom plate member for leaking the hardener is attached and fixed along the recess of the sheet pile wall at the lower end of the wall portion, and a gap portion surrounded by the bottom plate member, the sheet pile wall, and the inner peripheral surface of the shade concrete block A method of filling the gap with a curing agent such as concrete and curing and fixing (see Patent Document 1), or a cap concrete block installed on the top of the sheet pile wall via a height adjustment bolt or the like The bottom plate member for hardening agent leakage is suspended from the outside of the front wall portion, and the bottom plate member is placed along the recess of the sheet pile wall with the bottom plate member, the sheet pile wall, and the inner peripheral surface of the cap concrete block. Shape the enclosed gap And, this was fixed by filling and curing a curing agent such as concrete in the gap portion, the method (refer to Patent Document 2.) To remove the bottom plate member is known.

Japanese Patent No. 3295928 Japanese Patent No. 3211228

  The present invention enables a construction method different from those in Patent Documents 1 and 2 above, and further improves the workability and shortens the work period. A bottom plate is provided.

  The gist of the present invention will be described with reference to the accompanying drawings.

  A plurality of steel sheet piles 1 are placed along the riverbank and the coast to construct a concave and convex sheet pile wall 2 that continuously enters and exits the water surface as seen from the plane, and a cap concrete block 6 is supported on this sheet pile wall 2 A block concrete block 6 having a ceiling wall portion 6A having an opening 7 and a front wall portion 6B depending from the front end of the ceiling wall portion 6A is attached to the block bearing device 5. This cap concrete block 6 is placed so as to cover the upper part of the sheet pile wall 2, and the hardener 10 is put into the cap concrete block 6 from the opening 7 of the ceiling wall portion 6 A of the cap concrete block 6. A bottom plate 3 for formwork used for the construction of a cap concrete block for pouring and filling and integrating the cap concrete block 6 with the sheet pile wall 2, from the opening 7 of the ceiling wall portion 6 </ b> A of the cap concrete block 6. A plurality of plate members that can be placed on the bottom plate support 4 attached to the sheet pile wall 2 and the bottom plate placement projection 8 that projects from the lower end of the front wall portion 6B toward the horizontal rear side. 3A, the plurality of plate members 3A are provided with overlapping portions 11 at both ends, and the piled portions 11 of the respective plate members 3A are overlapped with each other, and the sheet pile wall 2 and the shade concrete block 6 are combined. The present invention relates to a bottom plate for a formwork used for the construction of a shaded concrete block, characterized in that it is formed in a shape capable of closing the concavo-convex gap 9 between the inner wall of the front wall 6B.

  Further, the overlapping portions 11 of the plurality of plate members 3A are formed in a thin plate shape so that the overlapping portions 11 can be vertically overlapped, and the overlapping portions 11 of the respective plate members 3A are overlapped. 2. The formwork bottom plate for use in the construction of a shaded concrete block according to claim 1, wherein the position can be changed in accordance with the shape of the concavo-convex shape gap portion 9. It is.

  The plurality of plate members 3A are configured by adopting a lightweight metal plate having a thickness of 3 mm or less and applying a reinforcing process 15 such as a rib process to the surface of the metal plate. This relates to a bottom plate for formwork used for the construction of the cap concrete block according to any one of items 1 and 2.

  Further, the water passage hole 14 is formed through the plurality of plate members 3A, and the hole diameter dimension of the water passage hole 14 is set to a small hole diameter dimension in which the curing agent 10 is difficult to leak out. It concerns on the baseplate for formwork used for construction of the shade concrete block of any one of 1-3.

  Since the present invention is configured as described above, the bottom plate for formwork can be inserted into the concavo-convex gap through the opening of the top wall portion of the cap concrete block and placed on the bottom plate support and the bottom plate mounting projection. Therefore, the fixing work of the bottom plate for the formwork is not necessary at all and can be applied very easily. The bottom plate for the formwork is composed of a plurality of plate members, and the plurality of plate members are arranged side by side to overlap each other. The bottom plate for formwork is very easy to handle because it is a shape that can close the uneven gap between the sheet pile wall and the inner surface of the front wall of the shaded concrete block by overlapping the parts. It excels in workability and can be closed as much as possible by arranging a plurality of plate members with a simple operation according to the shape of the concave and convex shape gap, so that the opening can then be put into the concrete block When the hardener is injected and filled, this Since the hardener can be effectively leaked with the bottom plate for the frame, the concrete block can be firmly fixed and fixed, and the entire bottom plate for the formwork is hardened with the hardener (because the bottom plate for the formwork is discarded as a formwork) ), It is not necessary to remove the mold after the curing agent is cured, and the mold can not be used in another part until the curing of the curing agent is completed. It can be installed and installed, and the construction period can be significantly shortened. For example, it becomes a base plate for formwork used for the construction of a groundbreaking concrete block with a simple structure with excellent practicality.

  Further, in the invention according to claim 2, the structure of the plurality of plate members whose shape can be easily changed in accordance with the shape of the concavo-convex shape gap portion is made more simple and the design can be easily realized. It becomes the bottom plate for formwork used for the construction of excellent shade concrete blocks.

  Further, in the invention according to claim 3, since the bottom plate for the formwork is light and easy to handle, the construction workability of the bottom plate for the formwork is further improved, and while the bottom plate for the formwork is a thin plate, Since it has strength by reinforcement processing, it does not bend even when it is filled with a hardener, and it is possible to satisfactorily prevent leakage of the hardener.

  Further, in the invention described in claim 4, since the hardening agent can be filled even when the water level of the river or the sea rises, it is possible to further reduce the work period and to improve the practicality of the shade concrete block. It becomes the bottom plate for formwork used for construction.

  An embodiment of the present invention that is considered to be suitable (how to implement the invention) will be briefly described with reference to the drawings, showing the operation of the present invention.

  The bottom plate 3 for formwork of the present invention is constructed with an uneven sheet pile wall 2 that continuously enters and exits the water surface as seen from the plane along the riverbank and coast, and a cap concrete block 6 is placed on the top of the sheet pile wall 2. It is used in the construction method of the shade concrete block 6 that is installed and fixed in a large number of juxtaposed states.

  Specifically, a plurality of steel sheet piles 1 are laid along the riverbank and the shore, and an uneven sheet pile wall 2 that continuously enters and exits the water surface as seen from the plane is constructed. When a block support 5 for supporting the concrete block 6 is attached, the cap concrete block 6 is supported on the block support 5, and the cap concrete block 6 is arranged so as to cover the upper portion of the sheet pile wall 2, the sheet pile wall The concavo-convex gap 9 is formed between the inner wall 2 and the inner surface of the front wall 6 </ b> B of the cap concrete block 6.

  In addition, before or after the cap concrete block 6 is placed on the upper portion of the sheet pile wall 2, the bottom plate support 4 for mounting and supporting the formwork bottom plate 3 of the present invention is attached to the sheet pile wall 2.

  Next, the mold base plate 3 of the present invention is inserted into the concave-convex gap portion 9 from the opening 7 of the ceiling wall portion 6A of the cap concrete block 6, and the base plate 3 for mold is attached to the bottom plate support. 4 and the bottom plate mounting projection 8 projecting from the lower end of the front wall portion 6B of the cap concrete block 6 toward the horizontal rear side, and the uneven gap 9 is closed.

  At this time, the concave and convex shape gap portion 9 is often formed by a plurality of plate members 3A, although the shape is not constant due to deformation of the steel sheet pile 1 itself, inclination at the time of driving, or the like. In a shape in which the uneven gap 9 between the sheet pile wall 2 and the inner surface of the front wall 6B of the cap concrete block 6 can be closed in a state where the overlapping portions 11 provided at both ends are aligned. The formed mold base plate 3 of the present invention can be changed in shape according to the shape of the concavo-convex gap 9 by changing the overlapping position of the overlapping portions 11 of the plurality of plate members 3A. Therefore, it is possible to close the plurality of plate members 3A side by side as easily as possible regardless of the shape of the concave-convex gap 9 having any shape.

  Further, since the plurality of plate members 3A are easier to handle than the case where the bottom plate 3 for formwork is constituted by a single large plate member, the plate members 3A are placed in the shade concrete block 6 from the opening 7. It is also easy to perform insertion and rearrangement according to the shape of the concavo-convex gap 9.

  Thereafter, when the hardener 10 is poured and filled into the concrete block 6 through the opening 7, the mold bottom plate 3 prevents the hardener 10 from leaking downward, and the inside of the concave gap 9 As the curing agent 10 is cured, the cap concrete block 6 and the sheet pile wall 2 are integrally fixed.

  Therefore, it is very easy to close the uneven gap 9 by inserting the plate member 3A from the opening 7 of the cap concrete block 6 arranged above the sheet pile wall 2 into the uneven gap 9 and placing it side by side. In this state, the mold base plate 3 can be installed, and then the mold base plate 3 is directly filled with the curing agent 10 and cured together with the mold base plate 3. That is, the mold base plate 3 is discarded as the mold frame. As a result, there is no need to remove the mold after the curing agent 10 is cured, and it is possible to install and install the concrete block 6 one after another without waiting for the curing of the curing agent 10 to be completed. It will be a base plate for formwork used in the construction of groundbreaking shade concrete blocks that will excel and shorten the construction period significantly.

  Further, for example, if the base plate 3 for formwork employs a light metal plate having a thickness of 3 mm or less and is provided with a reinforcing process 15 such as rib processing on the surface of the metal plate, Since the bottom plate 3 is lightweight and easy to handle, it is possible to more easily perform the work of installing the bottom plate 3 for formwork in the concave-convex gap 9 in the shade concrete block 6 and this mold while being a lightweight thin plate. Since the frame bottom plate 3 has a high strength due to the reinforcement 15, it does not bend when the curing agent 10 is filled, and the leakage of the curing agent 10 can be well prevented.

  In addition, for example, if the water passage hole 14 is formed through the mold bottom plate 3 and the hole diameter of the water passage hole 14 is set to a small hole diameter that prevents the hardener 10 from leaking out, the river or sea When the water level rises due to changes in the tide level or the influence of waves generated by vessel navigation, water enters the concavo-convex gap 9 through the water passage hole 14, and thereby the bottom plate 3 for formwork Therefore, the closed state of the concave-convex gap portion 9 is well maintained, and there is little trouble of rearranging the plate member 3A, and water is transferred from the water passage hole 14 into the concave-convex gap portion 9. Even if water enters, water is drained from the water passage hole 14 by pouring the curing agent 10 into the concave-convex gap 9, so that the curing agent 10 can be filled even when the water level rises. Therefore, the rise in water level does not hinder the work, The construction period can be shortened.

  Specific embodiments of the present invention will be described with reference to the drawings.

  In the present embodiment, a plurality of steel sheet piles 1 are placed along the riverbank and the coast as shown in FIG. 1 to construct an uneven sheet pile wall 2 that continuously enters and exits the water surface as viewed from the plane. The present invention relates to the bottom plate 3 for the formwork used in the method for constructing the concrete block 6 in which a large number of the concrete blocks 6 are installed and fixed in a juxtaposed state on the upper part of the sheet pile wall 2.

  The concrete construction method of the cap concrete block 6 will be described in detail. As shown in FIGS. 2 and 3, the steel sheet pile 1 having a substantially U shape in plan view is engaged with the claw portions 1A at both ends thereof and continuously. The sheet pile wall 2 having concavities and convexities on both side surfaces is constructed.

  Next, a bottom plate support 4 for placing and supporting a formwork bottom plate 3 of this embodiment, which will be described later, and a block support 5 for supporting a cap concrete block 6 are attached to the sheet pile wall 2 (see FIG. 6). . The bottom plate support 4 may be attached by inserting the cap concrete block 6 in the upper portion of the sheet pile wall 2 and then inserting it into the cap concrete block 6 from the opening 7.

  As shown in FIGS. 3 and 6, the bottom plate support 4 includes a hook-shaped latching portion 13 that can latch the upper end of a bolt rod 16 having an L-shaped bottom plate bearing 18 attached to the lower end of the sheet pile wall 2. The operation nut 17 is screwed onto the bolt rod 16 and the bolt rod 16 is prevented from being detached from the hooking portion 13 by the operation nut 17.

  Further, the bottom plate support 4 is provided with adjusting means 12 that can adjust the bottom plate support 18 to be moved up and down by rotating the operation nut 17, and the bottom plate 3 for the formwork that is placed and supported on the bottom plate support 18. The mold bottom plate 3 can be stably placed and supported together with the bottom plate placing protrusion 8 described later by adjusting the height of the bottom plate.

  As shown in FIGS. 3 and 6, the block support 5 has a hemispherical block support 20 at its upper end, and a bolt rod 19 having an operation nut 21 secured to an upper position below the block support 20. The hook-shaped hooking portion 13 that can be hooked on the sheet pile wall 2 is inserted into the base end and screwed to a mounting nut 22 provided on the hooking portion 13.

  Further, the block support 5 is provided with adjusting means 12 capable of adjusting the block support portion 20 by rotating the operation nut 21 and adjusting the cap concrete block 6 supported by the block support portion 20 to be adjusted up and down. And can be supported in the correct posture. That is, each steel sheet pile 1 of the sheet pile wall 2 does not necessarily have a constant height at the upper end, but it can be dealt with by adjusting the height of the block support 20 of the block support 5 uniformly. 6 can be supported in the correct posture. At this time, since the block support portion 20 has a smooth hemispherical shape, the friction resistance between the block support portion 20 and the inner surface of the top wall portion 6A of the cap concrete block 6 is small, and the rotation operation of the operation nut 21 is performed. The configuration is such that (the operation of the adjusting means 12) is performed relatively easily.

  The bottom plate support 4 and the block support 5 are attached to the plurality of sheet pile walls 2 by hooking the hook 13, and the cap concrete block 6 is supported on the block support 20 of the plurality of block supports 5. To do.

  The cap concrete block 6 is made of precast, and as shown in FIG. 4, a ceiling wall portion 6A having an opening 7, a rear wall portion 6C hanging from the rear end of the ceiling wall portion 6A, and the ceiling wall The front wall 6B that hangs down from the front end of the part 6A is integrally molded in a substantially inverted U-shaped cross section in a side view.

  Further, a protrusion 8A is integrally projected from the lower end of the front wall portion 6B toward the horizontal rear, and the integrally formed protrusion 8A is placed on the bottom plate mounting protrusion 8 to be described later. It is said.

  The cap concrete block 6 is lifted using a crane or the like, lowered to the upper portion of the sheet pile wall 2 and the inner surface (lower surface) of the ceiling wall portion 6A is supported by the block support portion 20, and the cap concrete block 6 is attached to the sheet pile wall 2. After being arranged so as to cover the upper part, the concrete block 6 is corrected to a correct posture by the adjusting means 12 of each block support 5 (see FIGS. 7 and 8).

  Then, as shown in FIGS. 3 and 8, a concavo-convex gap 9 is formed between the sheet pile wall 2 and the inner surface of the front wall 6 </ b> B of the cap concrete block 6.

  Next, the mold bottom plate 3 having a shape capable of closing the uneven gap portion 9 is inserted into the uneven gap portion 9 through the opening 7 of the ceiling wall portion 6A of the cap concrete block 6, and the adjustment is performed. By adjusting the height of the bottom plate support portion 18 of the bottom plate support 4 by means 12, the mold bottom plate 3 is stably placed on the plurality of bottom plate support 4 and the bottom plate mounting projections 8. Then, the uneven gap 9 is closed (see FIG. 8).

  Here, the formwork bottom plate 3 according to the present embodiment will be described in detail. As shown in FIG. 5, the bottom plate 3 is composed of a lightweight and easy-to-handle metal plate having a thickness of 1 mm, and is bent when filled with the curing agent 10 described later. As a reinforcement process 15 for prevention, many ribs (press process) of chevron and cross pattern (cross pattern in the drawing) are applied on the surface.

  In addition, as shown in FIGS. 2, 3 and 5, the formwork bottom plate 3 is a plate portion having a shape (substantially trapezoidal) substantially matching one half of the concave portion of the sheet pile wall 2 in plan view. And a plate member 3 </ b> A in a shape that is substantially integrated with a half portion of one side of the convex portion of the sheet pile wall 2 (substantially belt-like shape), and the other half on the other side of the concave portion of the sheet pile wall 2 A plate having a shape in which the plate portion having a shape substantially matching the portion (substantially trapezoidal shape) and the plate portion having a shape substantially matching the half portion on the other side of the convex portion of the sheet pile wall 2 (substantially in the shape of a band) are integrated. The plate member 3A is composed of two types of plate members 3A, and both end portions of the two types of plate members 3A are used as overlapping portions 11, and a large number of the plate members 3A are formed in a state where the overlapping portions 11 are overlapped with each other. The gap 9 is configured to be able to be closed.

  Further, the shape of the bottom plate 3 for formwork is changed in accordance with the shape change of the concave and convex shape gap portion 9 by changing the overlapping position of the overlapping portions 11 of the plate members 3A to the vertical, horizontal and oblique methods. It is configured to be able to.

  That is, since the steel sheet pile 1 constituting the sheet pile wall 2 is inclined and driven, or the steel sheet pile 1 itself is deformed and the lateral width is widened or narrowed. In many cases, the shape and dimensions of the gap 9 are different depending on the location. Therefore, if the bottom plate 3 has a shape matching the product drawing of the steel sheet pile 2, the gap 9 may not enter the uneven shape gap 9. Although a gap may be generated, according to the configuration of the present embodiment, by shifting the overlapping positions of the overlapping portions 11 of each plate member 3A, for example, the mold bottom plate 3 is in a substantially horizontal state and has an uneven gap. Since the formwork bottom plate 3 can be changed so that the portion 9 can be closed without a substantial gap, the formwork bottom plate 3 can be stably placed by the bottom plate support 4 and the bottom plate placing projection 8. Yes (see FIG. 9).

  Further, since each plate member 3A is made thin, it can be easily cut and welded on site, and can be easily processed into a shape capable of closing the uneven gap 9.

  In addition, a plurality of small-diameter water holes 14 through which the curing agent 10 described later hardly leaks are formed in the formwork bottom plate 3 so as to be scattered.

  Therefore, even if the water level of the river or the sea rises due to the change of the tide level or the influence of the waves generated by the vessel navigation, the water enters the uneven gap 9 through the water passage hole 14, so The frame bottom plate 3 is difficult to float and is not likely to be displaced. Further, even when water enters the concave / convex gap 9 from the water passage hole 14, the water is drained from the through hole 14 by pouring the curing agent 10 into the concave / convex gap 9. Even when such a water level rises, the work of filling the curing agent 10 can be performed. Therefore, the water level rise does not hinder the work, and the construction period can be shortened.

  Next, a hardener 10 such as concrete is injected and filled into the cap concrete block 6 from the opening 7 of the top wall portion 6A of the cap concrete block 6 (see FIG. 10).

  At this time, since the concavo-convex gap 9 is closed by the bottom plate 3 for formwork, it does not leak downward. Then, by curing the curing agent 10, the shaded concrete block 6 and the sheet pile wall 2 are integrated, and the shaded concrete block 6 is fixed.

  Further, at this time, a large number of cross patterns existing on the surface of the mold bottom plate 3 enhance the adhesion to the curing agent 10, so that high installation and fixing strength can be obtained.

  FIG. 11 shows a case where the configuration of the bottom plate mounting projection 8 provided on the front wall 6B of the cap concrete block 6 is changed.

  Specifically, one side plate portion of the mounting member 8B having an L-shaped cross section is attached to the inner surface of the lower end of the front wall portion 6B of the cap concrete block 6, and the other side plate portion is horizontally rearward from the lower end of the front wall portion 6B. In the case where the other side plate portion of the mounting member 8B that protrudes rearward in the horizontal direction is the bottom plate mounting projection portion 8 on which the formwork bottom plate 3 of this embodiment can be mounted. It is.

  The present invention is not limited to the present embodiment, and the specific configuration of each component can be designed as appropriate.

It is a schematic explanatory perspective view which shows the construction completion state of a present Example. It is a description exploded perspective view of a present Example. It is the expansion explanation perspective view which partially cut away the shade concrete block in the construction completion state of a present example. It is a sectional side view which shows the shade concrete block of a present Example. It is an expansion explanatory top view which shows the baseplate for formwork of a present Example. It is a schematic explanatory sectional side view which shows the state which attached the baseplate support and the block support to the sheet pile wall of a present Example. FIG. 7 is a schematic side cross-sectional view illustrating a state in which the cap concrete block is intended to be supported on the block support tool, following FIG. 6. FIG. 8 is a schematic side cross-sectional view illustrating a state in which the bottom plate for formwork is inserted from the opening of the cap concrete block and placed on the bottom plate support, following FIG. 7. FIG. 9 is a schematic cross-sectional plan view illustrating the state in which plate members are arranged to try to close the concavo-convex-shaped gap portion after the block support is omitted. FIG. 10 is a schematic cross-sectional side view illustrating a state in which the hardener is injected and filled into the cap concrete block from the opening of the cap concrete block following FIG. 9. It is a sectional side view which shows another example of a cap concrete block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel sheet pile 2 Sheet pile wall 3 Form plate bottom plate 3A Plate member 4 Bottom plate support 5 Block support 6 Caps concrete block 6A Top wall 6B Front wall 7 Opening 8 Bottom plate mounting projection 9 Uneven shape gap
10 Hardener
11 Superposition part
14 Water vent
15 Reinforcement processing

Claims (4)

  A block bearing that supports a concrete block on the sheet pile by placing multiple steel sheet piles along the riverbank and coastline to construct an uneven sheet pile wall that continuously enters and exits the water surface as seen from the plane. Is attached to the block support, and the cap concrete block having a ceiling wall portion having an opening and a front wall portion depending from the front end of the ceiling wall portion is supported, and the cap concrete block is attached to the sheet pile. It is arranged so as to cover the upper part of the wall, and through the opening of the top wall portion of the cap concrete block, a hardener is injected and filled into the cap concrete block to integrate the cap concrete block with the sheet pile wall. A bottom plate for a formwork used for construction, which is inserted from the opening of the top wall portion of the cap concrete block and attached to the sheet pile wall, and below the front wall portion And a plurality of plate members that can be placed on the bottom plate placing projections projecting horizontally from the rear, and the plurality of plate members are provided with overlapping portions at both ends, and each plate Construction of a cap concrete block characterized in that it is formed in a shape capable of closing the uneven gap between the sheet pile wall and the inner surface of the front wall portion of the cap concrete block in a state where the overlapping portions of the members are overlapped The bottom plate for formwork.   The overlapping portions of the plurality of plate members are formed in a thin plate shape so that the overlapping portions can be vertically overlapped with each other. The bottom plate for formwork used for the construction of the shade concrete block according to claim 1, wherein the bottom plate is adapted to be changed according to the shape of the portion.   The plurality of plate members are configured by adopting lightweight metal plates having a thickness of 3 mm or less, and performing reinforcement processing such as rib processing on the surfaces of the metal plates. A bottom plate for formwork used for the construction of the cap concrete block according to any one of the above items.   The water hole is formed by penetrating through the plurality of plate members, and the hole diameter of the water hole is set to a small hole diameter in which the hardener is difficult to leak out. A bottom plate for formwork used in the construction of the shaded concrete block described in item 1.

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