Side plates for structural components

Abstract

To provide a lightweight structural side plate (20) that allows for easy formation of openings. [Solution] Multiple support parts (29, 26b, 27b) are provided protruding from the back surface (20b) of the structural side plate, and holes are drilled from the front surface (20a) while the structural side plate is supported by these support parts. The structural side plate is designed to have a removal area (31) that will be removed during the drilling process, and at least one support part (29) is provided protruding from the back surface of the removal area. In this way, most of the load applied to the structural side plate during drilling is borne by the support parts of the removal area, thus suppressing the load applied to the structural side plate. As a result, it becomes possible to lighten the structural side plate.

Description

Technical Field

[0001] The present invention relates to a side plate for a structure attached to the outer peripheral side surface of a laminated structure for a water storage tank formed by arranging a plurality of structural members with legs erected downward from the back surface of a base in horizontal and vertical directions.

Background Art

[0002] In residential areas where a large number of people live, it is common for most of the ground to be paved with asphalt or the like. When the ground is paved, it becomes difficult for rainwater and the like to penetrate into the ground, so urban water disasters such as floods are likely to occur. As one of the countermeasures, it is known to install a water storage tank underground. If a large amount of rainwater can be stored in the water storage tank, it is possible to prevent the occurrence of urban water disasters by gradually infiltrating the stored rainwater into the ground or gradually discharging it into rivers.

[0003] As a technology that enables easy installation of a water storage tank underground, a technology for forming a water storage tank by laminating a plurality of structural members is known. The structural member has a structure in which a plurality of legs for supporting the base are erected from the lower surface of a rectangular base. By turning this structural member upside down and abutting the tip of the leg of the structural member that is not turned upside down on the tip of the upward leg, two structural members can be stacked. Then, by arranging such two structural members (hereinafter, unit structures) in horizontal and vertical directions, a large-scale laminated structure can be formed. Since a large space supported by a plurality of legs is formed inside this large-scale laminated structure, by covering the entire outer periphery with a waterproof sheet and using the internal space as a water storage space, a large water storage tank can be easily installed underground.

[0004] Large soil pressure can be applied to the outer perimeter of a laminated structure installed underground as a water storage tank. To support this soil pressure, structural side plates are attached to the outer perimeter of the laminated structure. These structural side plates need to have sufficient rigidity to prevent bending or damage from soil pressure, which tends to make them heavy. Therefore, a structural side plate has been proposed in which a protrusion is formed from the structural side plate toward the laminated structure, and the tip of the protrusion abuts against the leg of the structural member that forms the laminated structure. In this way, even if the structural side plate is subjected to large soil pressure, the soil pressure can be supported by the leg of the structural member via the protrusion formed on the structural side plate, thus preventing bending, deformation or damage to the structural side plate without increasing the rigidity of the structural side plate itself (Patent Document 1).

[0005] Furthermore, inlet pipes for bringing rainwater into the water storage tank and outlet pipes for draining rainwater stored in the tank may be attached to the sides of the water storage tank. Alternatively, sediment may accumulate inside the water storage tank after prolonged use, and it may become necessary to allow inspection of the inside from the side of the water storage tank. Therefore, for some structural side plates, openings for inserting pipes or for internal inspection may be made using tools such as hole saws before they are attached to the side of the laminated structure. When forming openings in the structural side plates, it is necessary to stabilize the position of the structural side plate by placing it on a workbench or similar surface, and it is desirable to keep the structural side plate elevated from the workbench or similar surface. Therefore, support columns of the same height are erected from the four corners of the back side (the side facing the laminated structure) of the structural side plate, and the structural side plate is supported by the support columns at the four corners when forming the openings. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2008-248661 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, conventional technologies proposed still require the structural side panels themselves to have sufficient rigidity, making it difficult to reduce the weight of the structural side panels. The reason for this is as follows: When it becomes necessary to form an opening in a structural side panel, the structural side panel is placed on a workbench or similar surface, and the opening is formed from above using tools. At this time, a large load is applied to the location where the opening is formed, but the structural side panel is easily deflected because it is supported by support columns at the four corners, and if the structural side panel deflects, it becomes difficult to form the opening. To avoid this situation, the structural side panel itself needs to have sufficient rigidity, and as a result, the weight of the structural side panel increases.

[0008] This invention was made to solve the aforementioned problems of the conventional technology, and aims to realize a lightweight structural side plate that allows for easy formation of openings. [Means for solving the problem]

[0009] To solve the above-mentioned problems, the side plate for the structure of the present invention employs the following configuration. That is, A structural side plate for a water storage tank is used in conjunction with a laminated structure for a water storage tank, which is formed by arranging multiple structural members, each having legs erected downward from the underside of a base, in both horizontal and vertical directions, and is attached to the outer periphery of the laminated structure. The side plate for the aforementioned structure is designed to have a removal area that is to be removed by drilling holes from the side that is not attached to the laminated structure, while it is not attached to the laminated structure. Multiple support portions are provided protruding from the back surface of the structural side plate, which is the side to which the structural side plate is attached to the laminated structure, to support the structural side plate during the drilling process. At least one of the support portions is provided protruding from the back surface of the area to be removed. It is characterized by the following:

[0010] In the structural side plate of the present invention, multiple support parts are provided protruding from the back surface. When it is necessary to drill holes in the structural side plate, the holes are drilled from the front surface of the structural side plate while it is supported by the multiple support parts. Furthermore, the structural side plate is designed to have an area to be removed by drilling, and at least one support part protrudes from the back surface of the area to be removed.

[0011] During the drilling process, a large load is applied to the structural side plate. However, at least one of the multiple support points that support the structural side plate during drilling is formed on the back surface of the area to be removed by the drilling process. Therefore, most of the load applied to the structural side plate during drilling is borne by these support points, and the structural side plate itself is not subjected to a large load. As a result, the rigidity required for the structural side plate can be reduced, making it possible to lighten the structural side plate.

[0012] Furthermore, in the side plate for the structure of the present invention described above, a cylindrical support column may be erected as a support portion protruding from the back surface of the area to be removed.

[0013] During the drilling process, a large load is likely to be applied to the structural side plate, and the support portion protruding from the back of the area to be removed may bear the majority of this load. Therefore, the support portion protruding from the back of the area to be removed requires high strength, while at the same time, in order to reduce the weight of the structural side plate, it is desirable that the support portion of the area to be removed be as lightweight as possible. From this viewpoint, cylindrical support columns are suitable as support portions of the area to be removed because they have high strength, an extremely simple structure, and are lightweight.

[0014] Furthermore, in the structural side plate of the present invention described above, when the structural side plate is attached to the laminated structure, a contact portion that will abut against the leg portion of the structural member forming the laminated structure may be provided protruding from the back surface of the structural side plate. In addition, support portions may be provided protruding from the back surface other than the area to be removed, and at least one of the support portions protruding from the back surface other than the area to be removed may serve as a contact support portion that also functions as a contact portion.

[0015] In this way, at least one of the support parts protruding from the back surface other than the area to be removed can reuse the contact part, thus reducing the number of pure support parts, and as a result, it becomes possible to lighten the side plate for the structure.

[0016] Furthermore, the side plate for the structure of the present invention, which has the aforementioned contact portion, may be formed in a rectangular shape having an upper edge that is above in the direction of gravity when attached to the outer peripheral surface of a laminated structure, a lower edge that is below in the direction of gravity, and a pair of opposing side edges. The contact support portion may be provided protruding at least two locations on a straight line located midway between the upper edge and the lower edge, at a predetermined distance from one side edge and at a predetermined distance from the other side edge. In addition, a removal area may be assumed to be located between the two contact support portions on at least one side of the straight line midway between the upper edge and the lower edge, either on the upper or lower side.

[0017] This way, when drilling holes in the structural side plate, the two contact support parts and the support column protruding from the area to be removed will provide stable support for the structural side plate.

[0018] Furthermore, in the side plate for the structure of the present invention described above, which comprises two contact support parts and a support column protruding from the area to be removed, a mark indicating the load position during drilling may be formed in advance. The position of this mark may be on the side to be drilled, within the area to be removed, and inside the triangle formed by the support column and the two contact support parts.

[0019] By doing so, the position where the load is applied during the drilling process will always be inside the triangle formed by the support column and the two abutting support portions, so that the side plate for the structure can be stably supported.

Brief Description of the Drawings

[0020] [Figure 1] It is a perspective view showing the overall shape of the structural member unit 10 that forms the laminated structure 1 for the water storage tank to which the side plate 20 for the structure of this embodiment is applied. [Figure 2] It is a perspective view showing the detailed shape of the structural member 11 that forms the structural member unit 10. [Figure 3] It is a perspective view showing the outer shape of the leg portion 13 of the structural member 11 of this embodiment. [Figure 4] It is an explanatory view showing the unit structure 15 in which two structural members 11 are stacked one above the other. [Figure 5] It is an explanatory view showing how the structural member units 10 are laminated to form the laminated structure 1. [Figure 6] It is an explanatory view showing the side plate 20 for the structure of this embodiment attached to the unit structure 15 that forms the outer peripheral side surface of the laminated structure 1. [Figure 7] It is a perspective view showing the outer shape of the side plate 20 for the structure of this embodiment. [Figure 8] It is an explanatory view showing the cross-sectional shape obtained by horizontally cutting the tip portions of the abutting portions 26a to 26c and 27a to 27c of the side plate 20 for the structure. [Figure 9] It is an explanatory view showing the reason why the shapes of the center surfaces 26f and 27f of the abutting portions 26a, 26c, 27a, and 27c become tapered toward the abutting portions 26b and 27b, and the shapes of the side inclined surfaces 26s and 27s become thicker toward the abutting portions 26b and 27b. [Figure 10] It is an explanatory view showing the assumed removal region 31 on the side plate 20 for the structure by viewing the side plate 20 for the structure of this embodiment from the side of the surface 20a. [Figure 11] It is an explanatory view showing the shape of the side plate 20 for the structure of this embodiment when viewed from the side. [Figure 12] This is an explanatory diagram showing how the structural side plate 20 is supported at four points during the drilling process of the structural side plate 20 in this embodiment. [Figure 13] This is an explanatory diagram showing the locations where support columns 97 are erected on the conventional structural side plates 90. [Figure 14] This diagram illustrates why conventional structural side plates 90 tend to bend easily during the drilling process. [Figure 15] This diagram illustrates why the structural side plate 20 in this embodiment is less prone to bending and deformation during the drilling process. [Figure 16] This is an explanatory diagram of a modified structural side plate 20. [Modes for carrying out the invention]

[0021] Figure 1 is a perspective view showing the overall shape of a structural member unit 10 that forms a laminated structure 1 for a water storage tank to which the structural side plate 20 of this embodiment is applied. The structural member unit 10 has a structure in which four structural members 11 made of hard resin such as PP (polypropylene) are arranged, and each structural member 11 has a rectangular base 12 and four legs 13 that are erected downward from the four corners on the back surface of the base 12. The four bases 12 are arranged in a grid pattern in two rows vertically and horizontally, and the sides of adjacent bases 12 are connected by a bridging section (not shown). Therefore, by cutting the bridging section, one structural member unit 10 can be divided into two or four relatively easily.

[0022] Figure 2 is a perspective view showing the detailed shape of the structural member 11 that forms the structural member unit 10 described above. The base 12 of the structural member 11 has a structure in which plate-shaped ribs 12b are erected in a grid pattern on both sides of a rectangular plate-shaped member 12a to provide strength, and legs 13 are erected downward from the four corners of the base 12. In addition, although it is omitted from the drawing to avoid making the drawing complicated, a water passage hole is formed in the center of the plate-shaped member 12a in the part surrounded by the grid-like ribs 12b.

[0023] Figure 3 is a perspective view showing the external shape of the leg portion 13 erected from the base 12 of the structural member 11. As shown in Figure 3, the leg portion 13 of the structural member 11 in this embodiment has a shape that resembles a bundle of multiple element members 14 (six in the illustrated example). The element member 14 is formed in a shape (hereinafter referred to as a gutter shape) with side walls of approximately the same height erected on both sides of an elongated member, and the top side open. Hereinafter, the elongated member corresponding to the bottom surface of the gutter shape will be referred to as the bottom surface member 14a of the element member 14. The leg portion 13 has a shape that resembles a single leg formed by arranging multiple element members 14 in a ring shape with the open side of the gutter shape facing inward, and the upper end of the side wall of an element member 14 being integrated with the upper end of the side wall of the adjacent element member 14.

[0024] In addition, each element member 14 has a tapered shape, with the width of the bottom member 14a narrowing towards the tip, and the leg portion 13, which is made up of bundles of such element members 14, also has a tapered shape. Furthermore, in the multiple element members 14 arranged in a ring, a fitting projection 14t is provided at the tip of every other element member 14. The tips of the other element members 14 that do not have a fitting projection 14t are recessed relative to the fitting projection 14t, forming a fitting recess 14d.

[0025] Furthermore, the leg portion 13 has a hollow structure, and at the position where the leg portion 13 is connected to the base 12, the internal space of the leg portion 13 opens into the plate-shaped member 12a of the base 12, forming a large opening 12c. Note that the interior of the leg portion 13 does not necessarily have a simple hollow structure; reinforcing ribs may be provided protruding from the inner wall surface of the leg portion 13. Also, by inverting the orientation of the structural member 11, the fitting projection 14t at the tip of the downward-facing leg portion 13 of the normally oriented structural member 11 is fitted into the fitting recess 14d at the tip of the upward-facing leg portion 13, and the two structural members 11 are stacked vertically to form a unit structure 15.

[0026] Figure 4 is an explanatory diagram showing a unit structure 15 formed by stacking two structural members 11 vertically. As mentioned above using Figure 1, in this embodiment, four structural members 11 are combined into one structural member unit 10. Therefore, by stacking a structural member unit 10 with a normal orientation on top of a structural member unit 10 with an inverted orientation, four unit structures 15 can be formed at once. By arranging such unit structures 15 horizontally and stacking them vertically, a large-scale structure (hereinafter referred to as a laminated structure 1) can be easily formed, and if such a laminated structure 1 is formed underground, it can be used as a water storage tank. Figure 5 shows how a laminated structure 1 is formed by stacking a structural member unit 10 with a normal orientation on top of a structural member unit 10 with an inverted orientation.

[0027] Furthermore, when the laminated structure 1 is formed underground, large soil pressure may be applied to the outer periphery of the laminated structure 1. Therefore, in order to support this soil pressure, structural side plates 20 are attached to the outer periphery of the laminated structure 1, as shown in Figure 6. These structural side plates 20 are rectangular plate-like members, and their dimensions in the height and width directions are set to fit precisely onto the sides of the unit structures 15. For this reason, when attaching the structural side plates 20 to the sides of the laminated structure 1, one structural side plate 20 is attached to each side of the unit structures 15 that make up the laminated structure 1.

[0028] Figure 7 is a perspective view showing the external shape of the structural side plate 20 of this embodiment. The left side of the figure shows the external shape of the structural side plate 20 as seen from the surface 20a side, and the right side of the figure shows the external shape of the structural side plate 20 as seen from the back surface 20b side. The structural side plate 20 is a rectangular plate-like member made of a hard resin such as PP (polypropylene), with engaging claws 21 protruding from two locations on the upper edge and elastically deformable elastic claws 22 protruding from two locations on the lower edge. When attaching the structural side plate 20 to the unit structure 15 of the laminated structure 1, the structural side plate 20 is tilted, and the engaging claws 21 on the upper edge of the structural side plate 20 are fitted into the base 12 of the upper structural member 11 of the unit structure 15. Then, by rotating the structural side plate 20 with its upper edge as the axis of rotation, the elastic claws 22 on the lower edge are fitted into the base 12 of the lower structural member 11 of the unit structure 15 (see Figure 6).

[0029] Furthermore, on the left side of the structural side plate 20, three deep recesses 23a, 23b, and 23c are formed in a vertical line. These recesses 23a to 23c protrude from the back surface 20b to form three contact portions 26a to 26c, which will be described later. Similarly, on the right side of the surface 20a, three deep recesses 24a, 24b, and 24c are formed in a vertical line. These recesses 24a to 24c protrude from the back surface 20b to form three contact portions 27a to 27c, which will be described later.

[0030] Furthermore, the surface 20a of the structural side plate 20 has multiple through holes 25 that penetrate to the back surface 20b in locations where recesses 23a-23c and 24a-24c are not formed. These through holes 25 not only reduce the weight of the structural side plate 20, but can also function as water passages. In other words, the laminated structure 1 installed underground may be used to gradually discharge rainwater stored inside into the external soil, or to gradually take in rainwater contained in the external soil into the laminated structure 1. When the laminated structure 1 is used for these purposes, the through holes 25 also function as water passages for draining or letting in rainwater.

[0031] Furthermore, as shown in the right-hand portion of Figure 7, on the back surface 20b of the structural side plate 20, three contact portions 26a, 26b, and 26c are provided, arranged in a vertical line at a predetermined distance from one side of the structural side plate 20, and three contact portions 27a, 27b, and 27c are also provided, arranged in a vertical line at a predetermined distance from the other side. As described above, the three contact portions 26a to 26c are formed by three recesses 23a to 23c formed on the surface 20a protruding from the back surface 20b, and the three contact portions 27a to 27c are formed by three recesses 24a to 24c formed on the surface 20a protruding from the back surface 20b. Note that, to avoid making the drawing complicated, the six contact portions 26a to 26c and 27a to 27c have drainage holes formed at their tips, which are not shown. Therefore, even when the structural side plate 20 is stored with the surface 20a facing upwards, water will not accumulate in the recesses 23a-23c and 24a-24c on the back surface 20b.

[0032] Furthermore, when the structural side plate 20 is attached to the structural member 11, the six contact points 26a-26c and 27a-27c have the function of releasing the soil pressure received by the structural side plate 20 to the leg portion 13 of the structural member 11 by having the tips of the contact points 26a-26c and 27a-27c contact the leg portion 13 of the structural member 11. Here, as described above with reference to Figure 6, the structural side plate 20 is attached to the side of the unit structure 15. The unit structure 15 is formed by stacking two structural members 11 one above the other. The leg portion 13 erected on the structural member 11 has a directionality. That is, as shown in Figure 2, when viewing the leg portion 13 of the structural member 11 from the front in the figure, the bottom member 14a (see Figure 3) of the element member 14 that forms the leg portion 13 is in the front position. In contrast, when viewing the leg portion 13 of the structural member 11 from the right side in the figure, the connection portion of the two element members 14 (the portion between the two bottom surface members 14a) is in the front position. Therefore, when attempting to attach the structural side plate 20 to the structural member 11, the leg portion 13 of the structural member 11 can take on two orientations. If the orientation of the leg portion 13 is different, the shape of the tip portions of the contact portions 26a~26c, 27a~27c that abut the leg portion 13 will normally also be different. However, this would necessitate an increase in the types of structural side plates 20, resulting in problems such as incorrect assembly due to the use of the wrong structural side plate 20 and an increase in management man-hours. Therefore, in this embodiment, the shape of the tip portions of the contact portions 26a~26c, 27a~27c of the structural side plate 20 is as follows.

[0033] Figure 8 is an explanatory diagram showing the shape of the tip portions of the contact parts 26a-26c and 27a-27c of the structural side plate 20 in this embodiment. Figure 8(a) shows the cross-sectional shape obtained by cutting the tip portions of the contact parts 26a-26c and 27a-27c horizontally. As shown in the figure, the tip portions of the contact parts 26a-26c and 27a-27c have a flat surface formed in the center (hereinafter referred to as the central surface 26f, 27f) and surfaces formed at an angle to the left and right of the central surface 26f, 27f (hereinafter referred to as the side slopes 26s, 27s). These central surface 26f, 27f and side slopes 26s, 27s correspond to the fact that the orientation of the leg portion 13 when attempting to attach the structural side plate 20 can take two different orientations.

[0034] In other words, when attempting to attach the side plate 20 for the structure, if the orientation of the leg portion 13 is such that the bottom surface member 14a of the element member 14 is facing forward, the central surfaces 26f, 27f of the contact portions 26a~26c and 27a~27c will contact the leg portion 13, as illustrated in Figure 8(b). On the other hand, if the orientation of the leg portion 13 is such that the connection portion of the two element members 14 (the portion between the two bottom surface members 14a) is facing forward, the side slopes 26s, 27s will contact the leg portion 13, as illustrated in Figure 8(c). Moreover, when the contact portions 26a~26c and 27a~27c are in contact with the leg portion 13, the distance L from the contact portions 26a~26c and 27a~27c to the central axis CL of the leg portion 13 will be the same regardless of the orientation of the leg portion 13. Therefore, the same structural side plate 20 can be attached regardless of the orientation of the leg portion 13.

[0035] Furthermore, as described above using Figure 3, the leg portion 13 has a tapered shape, and the bottom surface member 14a of the element member 14 forming the leg portion 13 is inclined in a direction away from the structural side plate 20 as it approaches the tip of the leg portion 13. Accordingly, the central surfaces 26f, 27f and lateral slopes 26s, 27s of the contact portions 26a~26c, 27a~27c that abut the bottom surface member 14a are also inclined. As a result, among the three vertically aligned contact portions 26a~26c, the central surfaces 26f of the upper and lower contact portions 26a, 26c become tapered towards the middle contact portion 26b, and the lateral slopes 26s of the contact portions 26a, 26c become wider towards the contact portion 26b. Similarly, among the three vertically aligned contact portions 27a to 27c, the central surfaces 27f of the upper and lower contact portions 27a and 27c taper towards the middle contact portion 27b, while the lateral slopes 27s of the contact portions 27a and 27c widen towards the contact portion 27b. Furthermore, for the middle contact portions 26b and 27b, the shape of the central surfaces 26f and 27f is a drum shape where the width is narrowest at the middle, while the shape of the lateral slopes 26s and 27s is an inverted drum shape where the width is widest at the middle. This point will be explained in more detail.

[0036] Figure 9 is an explanatory diagram illustrating the reason why the shape of the central surfaces 26f, 27f tapers towards the contact surfaces 26b, 27b, and the shape of the side slopes 26s, 27s widens towards the contact surfaces 26b, 27b, using the three vertically aligned contact surfaces 26a~26c, or the lower contact surfaces 26c, 27c, as an example.

[0037] First, consider the cross-sectional views obtained by cutting the lower contact portions 26c and 27c at two locations: one far from the middle contact portions 26b and 27b (the DD cross-sectional position in Figure 9(a)) and another close to them (the EE cross-sectional position in Figure 9(a)). Figure 9(b) shows the cross-sectional views of the contact portions 26c and 27c and the leg portion 13 obtained at the DD cross-sectional position. Note that the dashed lines used to represent the cross-sectional shapes of the contact portions 26c and 27c and the leg portion 13 in Figure 9(b) correspond to the dashed lines used to represent the DD cross-sectional position in Figure 9(a). Also, for reference, the cross-sectional shapes of the contact portions 26c and 27c and the leg portion 13 at the EE cross-sectional position are shown with thin dashed lines in Figure 9(b).

[0038] Figure 9(c) shows cross-sectional views of the contact portions 26c, 27c and the leg portion 13 obtained at the EE cross-sectional position. In Figure 9(c), the cross-sectional shapes of the contact portions 26c, 27c and the leg portion 13 are shown with dashed lines because the EE cross-sectional position is shown with a dashed line in Figure 9(a). Also in Figure 9(c), for reference, the cross-sectional shapes of the contact portions 26c, 27c and the leg portion 13 at the DD cross-sectional position are shown with thin dashed lines.

[0039] As is clear from comparing Figure 9(b) and Figure 9(c), the cross-section of the leg portion 13 is smaller at the EE cross-section than at the DD cross-section. This is because the leg portion 13 is formed in a tapered shape. Furthermore, the smaller cross-section of the leg portion 13 means that the bottom member 14a of the leg portion 13 (see Figure 8(c)) that abuts against the side slopes 26s, 27s of the contact portions 26c, 27c recedes inward. As a result, the side slopes 26s, 27s of the contact portions 26c, 27c rise up to follow the receding bottom member 14a. Thus, the side closer to the contact portions 26b, 27b rises up, causing the side slopes 26s, 27s to incline. The direction of inclination is such that the side closer to the contact portions 26b, 27b moves closer to the leg portion 13 (the direction in which the amount of protrusion from the back surface 20b of the structural side plate 20 increases). Similarly, the central surfaces 26f and 27f of the contact portions 26c and 27c are also inclined so that the side closer to the contact portions 26b and 27b is inclined toward the leg portion 13.

[0040] Thus, as the lateral slopes 26s and 27s are inclined, the width of the portion sandwiched between the lateral slopes 26s and 27s (i.e., the central surfaces 26f and 27f) becomes narrower. For this reason, the shape of the central surfaces 26f and 27f tapers towards the middle contact portions 26b and 27b. Also, because the central surfaces 26f and 27f taper, the lateral slopes 26s and 27s become wider towards the middle contact portions 26b and 27b. The above explanation applies to the lower contact portions 26c and 27c, but the same explanation applies to the upper contact portions 26a and 27a. Furthermore, for the middle contact portions 26b and 27b, the leg portion 13 is thinnest at the center and becomes wider as it moves away from the center. Therefore, the central surfaces 26f and 27f have a drum-like shape where the width is narrowest at the center, while the lateral slopes 26s and 27s have an inverted drum-like shape where the width is widest at the center.

[0041] In this embodiment, the central surfaces 26f, 27f and the lateral slopes 26s, 27s of the contact portions 26a~26c, 27a~27c are inclined in order to increase the contact area with the leg portion 13. However, if it is not necessary to increase the contact area with the leg portion 13, the central surfaces 26f, 27f and the lateral slopes 26s, 27s of the contact portions 26a~26c, 27a~27c do not need to be inclined.

[0042] Furthermore, as will be described in detail later, the central contact portion 26b among the three contact portions 26a to 26c, and the central contact portion 27b among the three contact portions 27a to 27c, are higher (protrude more) than the other contact portions 26a, 26c, 27a, and 27c, and also function as support portions that support the structural side plate 20 when drilling holes in the structural side plate 20. Therefore, these contact portions 26b and 27b correspond to the "support contact portions" in the present invention.

[0043] Furthermore, on the back surface 20b, in areas where the abutment portions 26a-26c and 27a-27c are not provided, a grid-like reinforcing rib 28 is formed over almost the entire surface, with a height lower than the abutment portions 26a-26c and 27a-27c. In addition, on the back surface 20b of the structural side plate 20, cylindrical, hollow support columns 29 are provided protruding between the three rows of abutment portions 26a-26c and the three rows of abutment portions 27a-27c, and at the upper and lower edges of the structural side plate 20. Moreover, in the structural side plate 20, there may be cases where it is necessary to make an opening for inserting a pipe or for inspecting the inside of the laminated structure 1, and in preparation for such cases, an area that can be removed during the drilling process (hereinafter referred to as the "area to be removed") is assumed. As will be described in more detail later, the support column 29 in this embodiment has the function of supporting the structural side plate 20 when drilling holes in the structural side plate 20, and thus corresponds to the "support part" in the present invention.

[0044] Figure 10 is an explanatory diagram showing the area to be removed 31 assumed for the structural side plate 20 of this embodiment, as viewed from the surface 20a side of the structural side plate 20. As mentioned above, the surface 20a of the structural side plate 20 has rows of three recesses 23a to 23c and rows of three recesses 24a to 24c, with the central contact portions 26b and 27b being higher than the other contact portions 26a, 26c, 27a, and 27c. The first area to be removed 31 is assumed to be approximately in the center, above the straight line connecting these two higher contact portions 26b and 27b, and in the area between the two rows formed on the left and right. The second area to be removed 31 is assumed to be approximately in the center, below the straight line connecting the two higher contact portions 26b and 27b, and in the area between the two rows formed on the left and right. In Figure 10, the areas to be removed 31 are shown with diagonal lines. Furthermore, smaller marking holes 30a and 30b than the through-hole 25 are formed in the two upper and lower removal regions 31 to serve as markers during the drilling process. In Figure 10, it is shown that two marking holes 30a and 30b are formed in each removal region 31, but the number of marking holes is not limited to two; it can be one or three or more.

[0045] When drilling holes in the structural side plate 20 using a tool such as a hole saw, the hole saw is positioned by pressing the tip of the center drill of the hole saw against either of the marking holes 30a or 30b, and then the hole saw is rotated in that position to form an opening in the structural side plate 20. Therefore, the marking holes 30a and 30b also function as "marks indicating the load position" during drilling. When marking hole 30a is used to position the hole saw, a circular opening shown by the dashed line in Figure 10 can be formed. When marking hole 30b is used, a circular opening shown by the dashed line can be formed. Furthermore, when positioning using marking hole 30b, a larger diameter hole saw can be used to form a larger opening shown by the dashed line in the figure. The size of the opening is predetermined by the outer diameter of the pipe to be inserted, so if the positions of the marking holes 30a and 30b are determined when designing the structural side plate 20, the range assumed to be the area to be removed 31 is automatically determined.

[0046] In this embodiment, the structural side plate 20 has marking holes 30a and 30b for positioning the hole saw. However, if the hole saw can be positioned, it is not necessary to form the marking holes 30a and 30b. For example, instead of marking holes 30a and 30b, small indentations may be formed on the surface 20a of the structural side plate 20. In this case as well, the opening can be formed in exactly the same way by positioning the hole saw using the indentations. Alternatively, instead of forming indentations, small marks may be made. In this case as well, the opening can be formed in exactly the same way by forming indentations at the marks using a center punch or the like. However, if marking holes 30a and 30b that penetrate to the back surface 20b, as in the structural side plate 20 of this embodiment, they can function as water passage holes, similar to through holes 25.

[0047] As described above using Figure 7, two support columns 29 are erected on the back surface 20b of the structural side plate 20. These support columns 29 are positioned in the upper and lower removal areas 31 shown in Figure 10. These support columns 29 are used as pillars to support the structural side plate 20 when drilling holes in it. Normally, such pillars would be erected one at each of the four corners of the structural side plate 20. However, in the structural side plate 20 of this embodiment, it is sufficient to erect one pillar each from the upper and lower removal areas 31. This is because the height of the support columns 29 is the same as the height of the contact portions 26b and 27b.

[0048] Figure 11 is an explanatory diagram showing the shape of the structural side plate 20 as viewed from the side (in the direction of arrow P in Figure 10). As shown, contact portions 26a-26c and 27a-27c protrude from the back surface 20b of the structural side plate 20. These contact portions 26a-26c and 27a-27c support the structural side plate 20 from the back surface 20b by contacting the leg portion 13 of the unit structure 15 when the structural side plate 20 is attached to the unit structure 15 of the laminated structure 1. As shown in Figure 11, in this embodiment, the contact portions 26a-26c and 27a-27c protruding from the back surface 20b of the structural side plate 20 have a truncated pyramidal shape that tapers from the base to the tip. However, it is not necessary to have a truncated pyramidal shape; for example, a prism shape may also be used.

[0049] As mentioned above, the unit structure 15 is formed by placing the leg portion 13 of a structural member 11 that is not inverted on top of the leg portion 13 of a structural member 11 that is inverted vertically. The upper contact portions 26a and 27a of the contact portions 26a-26c and 27a-27c abut against the leg portion 13 of the upper structural member 11, and the lower contact portions 26c and 27c abut against the leg portion 13 of the lower structural member 11. The central contact portions 26b and 27b abut against the connection portion between the lower leg portion 13 and the upper leg portion 13. As mentioned above, the leg portion 13 is formed in a tapered shape, so the leg portion 13 is narrowest at the connection portion between the lower leg portion 13 and the upper leg portion 13. In response to this, the central contact portions 26b and 27b protrude more from the back surface 20b compared to the other contact portions 26a, 26c, 27a, and 27c. As shown in Figure 11, the height of the support column 29 is set to the same height as the central contact portions 26b and 27b. Therefore, by erecting at least one support column 29 in each area to be removed 31, the two contact portions 26b and 27b and the two support columns 29 can support the structural side plate 20.

[0050] Figure 12 is an explanatory diagram showing the positions where the structural side plate 20 is supported when it is placed on a workbench or the like. The areas with diagonal lines in Figure 12 are the points where the structural side plate 20 is supported. In this way, the structural side plate 20 can be supported at four points (top, bottom, left, and right), so the structural side plate 20 can be held in a stable position even when drilling holes in it.

[0051] The structural side plate 20 of this embodiment, as described above, not only allows for a reduction in the number of support columns 29 from four to two, but also reduces the rigidity of the structural side plate 20. As a result, it is possible to significantly reduce the weight of the structural side plate 20. The reasons for this will be explained in detail below, but as preparation, a general structural side plate 90 in which support columns 99 are erected based on conventional thinking will be briefly described.

[0052] Figure 13 is an explanatory diagram of a typical structural side plate 90 with support columns 99 erected based on conventional thinking. For ease of understanding, the structural side plate 90 shown in Figure 13 is assumed to be exactly the same as the structural side plate 20 of this embodiment, except for the position of the support columns 99. Accordingly, the same numbers or symbols are used for elements common to both the structural side plate 90 and the structural side plate 20.

[0053] As shown in Figure 13, in the conventional approach, when erecting support columns 99 on the back surface of a structural side plate 90, the support columns 99 are erected from the four corners of the structural side plate 90. The reason for this is that supporting the structural side plate 90 at all four corners makes the posture of the structural side plate 90 more stable. For example, compared to the structural side plate 20 of this embodiment shown in Figure 12, the structural side plate 20 of this embodiment may tilt if any of its four corners are strongly pressed, but the structural side plate 90 in Figure 13 is less likely to tilt because support columns 99 are formed at all four corners. In addition, the height of the support columns 99 is set higher than the central contact portions 26b and 27b so that they do not interfere when the support columns 99 support the structural side plate 90. However, such conventional structural side plates 90 tend to bend easily during the drilling process.

[0054] Figure 14 is an explanatory diagram illustrating why conventional structural side plates 90 are prone to bending during hole drilling. Even with conventional structural side plates 90, when drilling holes, the structural side plate 90 is placed on a workbench or similar surface, and the surface is processed using a tool such as a hole saw. The diagonal arrows in Figure 14 indicate that a strong force is applied to the center of the structural side plate 90 during hole drilling. This force is supported by the support columns 99 formed at the four corners of the structural side plate 90, and since these support columns 99 are far apart, the structural side plate 90 bends significantly. The dashed lines in Figure 14 represent the bent structural side plate 90. When the structural side plate 90 bends in this way, not only does the processed area become unstable, but if the amount of bending is large, the contact parts 26b and 27b protruding from the back side come into contact with the workbench, making the posture of the structural side plate 90 unstable. Furthermore, when the structural side plate 90 flexes, the structural side plate 90 at the point where the support column 99 is erected tilts. As a result, the support column 99 also tilts, making the posture of the structural side plate 90 unstable. In order to avoid this, the rigidity of the structural side plate 90 must be sufficiently large, which inevitably increases the weight of the structural side plate 90.

[0055] In contrast, in the structural side plate 20 of this embodiment, at least one support column 29 is erected on the back side of the area to be removed 31, so there is no need to increase the rigidity of the structural side plate 20. That is, for example, when forming an opening in either the upper or lower area to be removed 31 as shown in Figure 10, the hole saw is positioned using either the upper or lower marking holes 30a or 30b, and the drilling process is performed. At this time, a large force is applied to the structural side plate 20, but since the support column 29 is erected within the area to be removed 31 that is to be drilled, most of the force applied to the structural side plate 20 can be supported by the support column 29.

[0056] Figure 15 is an explanatory diagram showing how the load applied to the structural side plate 20 during drilling is supported by the support column 29, as viewed from the direction of arrow Q shown in Figure 10. In Figure 15, it appears as if the load is applied from directly above the support column 29, but in reality, the position of the load and the position of the support column 29 are offset in the depth direction on the drawing, so the load is not necessarily applied from directly above the support column 29. However, since the support column 29 is erected from within the area to be removed 31 that is to be drilled, it can receive the load at a position close to the load position, and as a result, it can support most of the force that the structural side plate 20 receives during drilling.

[0057] In addition, the marking holes 30a and 30b, which are used to position the center drill of the hole saw during drilling, are formed inside a triangle (shown as a thick dashed or dotted line in Figure 12) whose vertices are the two contact points 26b and 27b that support the structural side plate 20 during drilling and the support column 29. Therefore, during drilling, the load can be received at these three points, making it possible to stably support the posture of the structural side plate 20.

[0058] Of course, in the side plate 20 for the structure of this embodiment, if the area to be removed 31 is removed by drilling holes, the support column 29 will also be removed. In addition, it will not be possible to drill holes again in at least the same area to be removed 31. However, since the removal of the support column 29 means that the drilling process is complete, and it is unlikely that holes will be drilled again in the same area to be removed 31, the removal of the support column 29 does not cause any practical problems.

[0059] As explained in detail above, in the structural side plate 20 of this embodiment, the support column 29 can receive most of the force applied to the structural side plate 20 during drilling, so the structural side plate 20 will not bend even if its rigidity is low. Therefore, it is possible to lighten the structural side plate 20. In addition, since the support column 29 receives most of the force applied to the structural side plate 20, no large force is applied to the contact portions 26b and 27b. Therefore, the contact portions 26b and 27b only need to have enough rigidity to contact the leg portion 13 of the structural member 11 and receive the pressure of the soil. From this perspective as well, it is possible to lighten the structural side plate 20.

[0060] In the structural side plate 20 of the embodiment described above, the structural side plate 20 was described as being supported at four points by two abutment portions 26b and 27b protruding from the left and right positions on the back surface 20b of the structural side plate 20, and two support columns 29 protruding from the top and bottom positions on the back surface 20b of the structural side plate 20. However, the support columns 29 may be made by erecting one support column 29 from either the top or bottom position on the back surface 20b of the structural side plate 20, so that the structural side plate 20 is supported at three points. The following describes a structural side plate 20 of such a modified form.

[0061] Figure 16 is an explanatory diagram of a modified structural side plate 20. As shown, in the modified structural side plate 20, marking holes 30a and 30b are formed at the lower center of the surface 20a. Therefore, a removal area 31 is assumed around the marking holes 30a and 30b. However, marking holes 30a and 30b are not formed at the upper center of the surface 20a, and no removal area 31 is assumed there. Therefore, during the drilling process, the structural side plate 20 can only be supported at three points: by the contact portions 26b and 27b protruding from the left and right sides of the back surface 20b and by a single support column 29.

[0062] However, as described above using Figure 15, most of the force applied to the structural side plate 20 during drilling is received by the support column 29 in the area to be removed 31, so the absence of a second support column 29 does not cause any major problems. In addition, the support column 29 is formed in a position that encloses the mark holes 30a and 30b, with the left and right contact parts 26b and 27b and the support column 29 as its vertices. For this reason, the structural side plate 20 can be stably supported during drilling at three points: the left and right contact parts 26b and 27b and the support column 29.

[0063] Furthermore, in the modified structural side plate 20, an opening can only be formed at a position below the center of the surface 20a. However, if the structural side plate 20 is attached to the laminated structure 1 upside down, that is, with the engaging claws 21 facing downwards and the elastic claws 22 facing upwards, the same effect as forming an opening at a position above the surface 20a can be obtained. For this reason, in the modified structural side plate 20, further weight reduction can be achieved by reducing the number of support columns 29 without causing any practical problems.

[0064] Although the side plates 20 for the structure in this embodiment and its modified form have been described above, the present invention is not limited to the above embodiment and its modified form, and can be implemented in various forms without departing from the spirit of the invention. [Explanation of Symbols]

[0065] 1...Laminated structure, 10...Structural member unit, 11...Structural member, 12...base, 12a...plate-shaped member, 12b...rib, 12c...opening 13... Leg portion, 14... Element member, 14a... Bottom member, 14d... Fitting recess, 14t...Mating convex part, 15...Unit structure, 20...Structure side plate, 20a...front surface, 20b...back surface, 21...engaging claw, 22...elastic claw 23a~23c...recess, 24a~24c...recess, 25...through hole 26a~26c…joint portion, 27a~27c…joint portion, 26f…central surface, 26s…side slope, 27f…central surface, 27s…side slope, 28…reinforcing rib, 29… Support column, 30a, 30b… Imprint hole, 31… Removed area.

Claims

1. A structural side plate for a water storage tank is used in conjunction with a laminated structure for a water storage tank, which is formed by arranging multiple structural members, each having legs erected downward from the underside of a base, in both horizontal and vertical directions, and is attached to the outer periphery of the laminated structure. The side plate for the aforementioned structure is designed to have a removal area that is to be removed by drilling holes from the side that is not attached to the laminated structure, while it is not attached to the laminated structure. Multiple support portions are provided protruding from the back surface of the structural side plate, which is the side to which the structural side plate is attached to the laminated structure, to support the structural side plate during the drilling process. At least one of the support portions is provided protruding from the back surface of the area to be removed. A side plate for a structure characterized by the following features.

2. A side plate for a structure according to claim 1, The support portion protruding from the back surface of the area to be removed is a cylindrical support column. A side plate for a structure characterized by the following features.

3. A side plate for a structure according to claim 2, From the back surface, when the side plate for the structure is attached to the laminated structure, a contact portion is provided that abuts against the leg portion of the structural member of the laminated structure. The support portion is also provided protruding from the back surface other than the area to be removed. At least one of the support portions protruding from the back surface other than the area to be removed is a contact support portion that also serves as the contact portion. A side plate for a structure characterized by the following features.

4. A side plate for a structure according to claim 3, The side plate for the structure is formed in a rectangular shape having an upper edge that is upward in the direction of gravity when attached to the outer peripheral surface of the laminated structure, a lower edge that is downward in the direction of gravity, and a pair of opposing side edges. The contact support portion is provided protruding from at least two locations on a straight line located midway between the upper and lower edges, at a predetermined distance from one side edge and at a predetermined distance from the other side edge. The area to be removed is assumed to be located between the two contact support portions, at least one of the sides of the upper or lower edge that lies beyond the straight line midway between the upper and lower edges. A side plate for a structure characterized by the following features.

5. A side plate for a structure according to claim 4, Within the area to be removed, a mark indicating the load position during drilling is formed on the surface to be drilled, inside the triangular area formed by the position where the support column is erected and the two contact support parts. A side plate for a structure characterized by the following features.

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