Construction method for receiving frame for grating and masking member used in this construction method

Abstract

To provide a construction method for a receiving frame capable of reliably preventing concrete from adhering to a surface of the receiving frame during construction when the receiving frame is installed in a groove body.SOLUTION: A construction method for a receiving frame includes an outside form arrangement process, a receiving frame connection process, an inside form arrangement process, a concrete casting process, and a removal process. The receiving frame 2 comprises an angle member 21 extending in an extension direction of a side wall part 11, wherein the angle member 21 comprises a horizontal part 22 extending in a lengthwise direction and a vertical part 23 connected upward in a vertical attitude along one side edge of the horizontal part 22, the other side edge of the horizontal part 22 is connected in an attitude approaching an outside surface of an inside form 3, and a groove-shaped space 24 is formed between the vertical part 23 and the inside form 3. The construction method for the receiving frame comprises a masking process as a previous process of the concrete casting process, wherein the masking process includes preparing a masking member 5 having an outer shape along an inner shape of the groove-shaped space 24, fitting the masking member 5 into the groove-shaped space 24, and covering an inner surface of the angle member 21.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a method for installing a receiving frame for mounting a grating to be installed in a gutter such as a road gutter, a cross gutter, or a factory drainage gutter, and to a masking member used in this installation. [Background technology]

[0002] Gratings are used as gutter covers for road gutters, cross gutters, parking lots, and drainage gutters in factories. Gratings are metal covers formed by combining multiple main bars arranged vertically and parallel to each other inside a rectangular frame, with multiple cross bars intersecting these bars in a grid pattern. Gratings are generally required to have the drainage properties to efficiently guide rainwater from the road surface into the drainage gutters, and the strength to allow vehicles to pass over them.

[0003] In order to install such a grating in a fixed position at the upper opening of the trench, a grating frame is installed at the upper end of the trench to provide a mounting recess for mounting the grating. The grating frame is fixed in a state where a part of it is embedded in the concrete side wall that forms the trench. Therefore, when constructing the frame, a process of pouring concrete with the frame fixed in place is included.

[0004] In this way, when concrete is poured into the fixed frame to form the side wall, the poured concrete may spill over the boundary with the frame and onto the surface of the frame. For example, when the top surface of the poured concrete is leveled with a trowel, as shown in FIG. 23, some of the concrete that has spilled out beyond the top end of the frame 2 and into the inside may adhere to the inner surface of the frame 2 and become a concrete lump 81, which may cause a poor appearance. In addition, some frame 2 has a structure in which a screw part 27 for fixing a grating protrudes from the inner surface, but in order to prevent concrete from adhering to such a screw part 27, it is necessary to wrap masking tape 82 around the screw part 27 to mask it, which is a time-consuming task. In particular, when the concrete that has adhered to the surface of the frame 2 hardens and becomes a concrete lump 81, it is difficult to remove it reliably, and if concrete remains on the surface of the frame 2, there is a risk that the grating may become unsteady when it is installed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-328428 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve such problems in the past. One of the objects of the present invention is to provide a construction method for a grating frame, which can reliably prevent concrete from adhering to the surface of the frame during construction to install the grating frame in a trench body, and a masking member used in this construction method, which can prevent deterioration of the appearance and quality of the frame. Means for solving the problem and effects of the invention

[0007] A construction method of a receiving frame for a grating according to one embodiment of the present invention is a construction method of a receiving frame for a grating in which a receiving frame for placing a grating is fixed to the upper part of the side wall of a groove formed in the shape of a groove made of concrete, and includes an outer formwork positioning step of positioning an outer formwork that forms the outer surface of the side wall, a receiving frame connecting step of connecting the receiving frame to an inner formwork that forms the inner surface of the side wall, an inner formwork positioning step of positioning the inner formwork inside the outer formwork and positioning the receiving frame in a predetermined position, a concrete pouring step of filling the filling space formed between the outer formwork, the inner formwork, and the receiving frame with unhardened concrete to form a side wall to which the receiving frame is fixed, and a removal step of removing the inner formwork and the outer formwork after the poured concrete has hardened. The receiving frame connected to the inner form in the receiving frame connecting step comprises an angle member extended in the extension direction of the side wall portion, the angle member having an L-shaped cross section and comprising a horizontal portion extending in the length direction and a vertical portion connected upward in a vertical position along one side edge of the horizontal portion, the other side edge of the horizontal portion being connected to the inner form so as to be in a position approaching the outer surface of the inner form, and a groove-shaped space is formed between the vertical portion and the inner form. Furthermore, the receiving frame construction method includes a masking step, as a preliminary step to the concrete pouring step, of preparing a masking member having an outer shape that follows the inner shape of the groove-shaped space, fitting the masking member into the groove-shaped space, and bringing the masking member into close contact with the inner surface of the vertical portion to cover the inner surface of the angle member. In this specification, the term "unhardened concrete" is used in a broad sense to include not only ready mixed concrete but also mortar.

[0008] According to the above method, the masking material is fitted in a tight fit state into the groove-shaped space formed between the vertical part of the angle member constituting the frame and the inner formwork to cover the inner surface of the angle member, which has the advantage of reliably preventing concrete from adhering to the surface of the frame fixed to the upper part of the side wall of the groove body, and preventing the appearance of the frame from being deteriorated. In addition, according to this method, since it is possible to reliably prevent concrete from adhering to the surface of the frame, it is also possible to effectively prevent foreign matter from being caught between the grating and the frame when the grating is placed in the frame, thereby suppressing rattling of the grating.

[0009] In another aspect of the present invention, a method of constructing a receiving frame for a grating comprises an angle member having a plurality of threaded portions protruding upward from a horizontal portion, and a masking member having holes at positions opposite the threaded portions for guiding the threaded portions, and in a masking process, the masking member is inserted into a groove-shaped space while guiding the threaded portions into the holes.

[0010] According to the above method, even if the receiving frame has a threaded portion for screwing the grating, the threaded portion can be guided into and covered by a hole provided in the masking member, thereby reliably preventing concrete from adhering to the threaded portion, thereby enabling the grating to be stably attached.

[0011] In another aspect of the present invention, a method of constructing a receiving frame for a grating comprises a masking member having a main body portion which is pressed into a groove-shaped space and a spacer member which is stacked between the main body portion and the horizontal portion, and the spacer member has an outer shape which follows the inner shape of the groove-shaped space in a plan view and is molded to a uniform thickness so as to adjust the top surface height of the main body portion.

[0012] According to the above method, by stacking the spacer member between the main body portion and the horizontal portion, the height of the upper surface of the masking member can be adjusted according to the height of the vertical portion.

[0013] In another aspect of the present invention, a method for constructing a receiving frame for a grating comprises integrally molding a masking member using a resin foam, and in the masking process, elastically deforming the masking member so as to press it into the groove-shaped space.

[0014] According to the above method, the masking member is integrally molded from a resin foam, and in the masking process, the masking member is elastically deformed and pressed into the groove-shaped space, so that the masking member fits snugly into the groove-shaped space and is placed in close contact with the inner surface of the vertical part. In addition, because the masking member is made of a resin foam, it has the advantage that even if concrete adheres to the surface, it can be easily removed.

[0015] In another aspect of the present invention, a method of constructing a receiving frame for a grating includes a masking member having an elastic deformation portion that elastically deforms in the width direction of the groove-shaped space, and in the masking process, the elastic deformation portion can be elastically deformed and pressed into the groove-shaped space.

[0016] According to the above method, the masking member has an elastic deformation portion that elastically deforms in the width direction of the groove-shaped space, and in the masking process, the elastic deformation portion is elastically deformed and pressed into the groove-shaped space, so that the masking member can be fitted into the groove-shaped space without any gaps, and the masking member can be positioned in a tight contact state against the inner surface of the vertical portion.

[0017] A construction method for a receiving frame for a grating according to another aspect of the present invention comprises a groove comprising an existing groove having a pair of side wall bases erected on both sides of a bottom plate portion, and a poured concrete section formed by pouring concrete on top of the existing groove, and includes a step of preparing the existing groove as a preliminary step to an inner formwork placement step, in which a pair of inner formworks are fixed to the inner surface of the pair of side wall bases of the existing groove and angle members are placed in a fixed position above the side wall bases, and in the concrete pouring step, the poured concrete section is formed with concrete filled in the filling space, and the side wall section is formed by integrally connecting the poured concrete section to the side wall base.

[0018] In the above method, the gutter is constructed of an existing gutter with a pair of side wall bases erected on both sides of the bottom plate, and a poured concrete section formed by pouring ready mixed concrete on the existing gutter, so that the poured concrete section formed in the concrete pouring process is integrally connected to the side wall base of the existing gutter prepared in advance to form the side wall section. According to this method, the process of forming the side wall base of the side wall section and the process of forming the poured concrete section for fixing the receiving frame are separate processes, so that the receiving frame can be accurately positioned in the specified position while simplifying the process of fixing the receiving frame.

[0019] In another aspect of the present invention, a method of constructing a receiving frame for grating includes a receiving frame connecting process, which includes a form unit forming process in which both ends of a pair of inner formworks are connected with connecting plates to form a rectangular cylindrical form unit, and a receiving frame unit forming process in which angle members are fixed to the outer surfaces of each of a pair of inner formworks of the form unit to form a receiving frame unit, and a masking process, which is a process subsequent to the receiving frame unit forming process and prior to the inner formwork positioning process, in which a masking member is inserted into the groove-shaped space of the receiving frame unit, and in the inner formwork positioning process, the receiving frame unit with the masking member attached is positioned between a pair of side wall bases, and the angle member covered with the masking member is positioned in a fixed position above the side wall bases.

[0020] According to the above method, both ends of a pair of inner formworks are connected with connecting plates to form a rectangular formwork unit, and angle members are fixed to the outer surface of the inner formwork of the formwork unit to form a receiving frame unit.A masking member is then inserted into the groove-shaped space of the receiving frame unit, and the receiving frame unit with the masking member attached is then positioned between a pair of side wall bases as the inner formwork placement process.This allows the inner formwork to be simply and easily positioned on the inner surface of the side wall base, while the receiving frame can be reliably positioned in a fixed position on the side wall base, and also improves work efficiency.

[0021] A construction method for a grating frame according to another aspect of the present invention comprises a groove formed of an existing groove having a pair of side wall bases erected on both sides of a bottom plate portion, and a poured concrete portion formed by pouring concrete on the existing groove, and includes a step of preparing the existing groove as a pre-step of an inner formwork arrangement step, and a frame connection step includes a preparation step of preparing a four-sided frame having a rectangular shape in a plan view and angle members arranged on at least three sides as the frame, a formwork unit formation step of connecting both ends of a pair of inner formworks with a second inner formwork to form a rectangular cylindrical formwork unit, and a frame unit formation step of fixing angle members to the outer sides of the inner formwork and the second inner formwork of the formwork unit to form the frame unit, and a masking step is a step subsequent to the frame unit formation step, in which the inner formwork arrangement step includes a masking step. As a preliminary step to the placing step, a masking member is inserted into the groove-shaped space of the receiving frame unit, and in an inner formwork placing step, the receiving frame unit with the masking member attached is placed inside the side wall base, and the angle member covered with the masking member is placed in a fixed position above the existing groove body, and the concrete pouring step includes a wall forming step of filling the filling space with unhardened concrete and integrally connecting the poured concrete portion to the side wall base to form a side wall portion, and a lid forming step of placing a bridging member across the opposing side wall bases, pouring unhardened concrete on the bridging member, and filling a second filling space formed between the second inner formwork, the receiving frame, and the bridging member with unhardened concrete to form a lid portion to which the receiving frame is fixed, which closes the upper opening of the groove body.

[0022] In the above method, the gutter body is composed of an existing gutter body and a poured concrete section, and the concrete pouring process includes a wall formation process in which the poured concrete section is integrally connected to the side wall base to form the side wall section, and a lid formation process in which unhardened concrete is poured onto a bridging member placed across the opposing side wall bases to form a lid section that closes the upper opening of the gutter body.Therefore, a four-sided frame used as a receiving frame, which is rectangular in plan view and has angle members arranged on at least three sides, can be securely fixed by the side wall section and the lid section. In addition, according to the above method, both ends of a pair of inner formwork are connected with a second inner formwork to form a rectangular formwork unit, angle members are fixed to the outer surfaces of the inner formwork of the formwork unit and the second inner formwork to form a receiving frame unit, and after a masking member is inserted into the groove-shaped space of the receiving frame unit, the receiving frame unit with the masking member attached is positioned in a fixed position in the existing groove body.This means that the inner formwork and the second inner formwork can be simply and easily positioned inside the side wall base, while the receiving frame can be reliably positioned in a fixed position in the existing groove body, thereby improving work efficiency.

[0023] A masking member according to one embodiment of the present invention is a masking member used in the construction of a receiving frame for grating, which fixes the receiving frame for placing a grating to the upper part of the side wall of a groove formed of concrete in the shape of a groove, and the receiving frame has angle members extended in the extension direction of the side wall and arranged opposite each other, and the angle members have an L-shaped cross section and include a horizontal portion extending in the length direction and a vertical portion connected upward in a vertical position along one side edge of the horizontal portion, and the masking member is configured to be inserted into the groove-shaped space formed between the vertical portion and the inner formwork when the receiving frame is connected to the inner formwork so that the other side edge of the horizontal portion is close to the outer surface of the inner formwork that forms the inner surface of the side wall, and the masking member has an outer shape that follows the inner shape of the groove-shaped space, and when inserted into the groove-shaped space, it comes into close contact with the inner surface of the vertical portion to cover the inner surface of the angle member.

[0024] According to the above structure, the masking material can be fitted into the groove-shaped space formed between the vertical part of the angle member constituting the frame and the inner formwork to cover the inner surface of the angle member, and this has the advantage of reliably preventing concrete from adhering to the surface of the frame fixed to the upper part of the side wall of the groove body, thereby preventing the appearance of the frame from being deteriorated. In addition, since this masking material can reliably prevent concrete from adhering to the surface of the frame, it also has the advantage of suppressing foreign matter from remaining on the surface of the frame and suppressing rattling of the grating.

[0025] A masking member according to another aspect of the present invention has holes for guiding the threaded portions at positions opposite the threaded portions so that the masking member can be attached to a receiving frame having a plurality of threaded portions protruding upward from a horizontal portion.

[0026] According to the above method, even if the receiving frame has a threaded portion for screwing the grating, the threaded portion can be guided into and covered by a hole provided in the masking member, thereby reliably preventing concrete from adhering to the threaded portion, thereby enabling the grating to be stably attached. [Brief description of the drawings]

[0027] [Figure 1] This is an oblique view showing a groove body in which a receiving frame is installed by a construction method for a receiving frame for a grating according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional perspective view of the groove body shown in FIG. [Diagram 3] This is a schematic cross-sectional view showing the topographical work in the preparation process of an existing trench body in the construction method for a receiving frame for a grating in one embodiment of the present invention. [Figure 4] This is a schematic cross-sectional view showing the reinforcement work in the preparation process of an existing groove body in the construction method for a grating frame according to one embodiment of the present invention. [Diagram 5] This is a schematic cross-sectional view showing the molding process of the preparation step of the existing groove body in the construction method of a receiving frame for a grating according to one embodiment of the present invention. [Figure 6]A schematic cross-sectional view showing the inner formwork placement step of a method for constructing a receiving frame for a grating in one embodiment of the present invention. [Figure 7] A schematic cross-sectional view showing the inner formwork placement step of a method for constructing a receiving frame for a grating in one embodiment of the present invention. [Figure 8] 1 is a schematic cross-sectional view showing a concrete pouring step in a method for constructing a grating frame according to one embodiment of the present invention. FIG. [Figure 9] A schematic cross-sectional view showing the state in which a grating is placed on a receiving frame constructed by a construction method according to one embodiment of the present invention. [Figure 10] This is an oblique view showing the receiving frame, which is a frame on all four sides. [Figure 11] This is an oblique view showing a receiving frame unit with four frames connected. [Figure 12] 1 is a perspective view showing a frame unit formed by connecting frames which are through frames. FIG. [Figure 13] 13 is a cross-sectional view showing the process of connecting the through frame to the inner formwork. FIG. [Figure 14] 13 is a cross-sectional view showing the process of connecting the through frame to the inner formwork. FIG. [Figure 15] 13 is a cross-sectional view showing the process of connecting the through frame to the inner formwork. FIG. [Figure 16] 13 is a cross-sectional view showing the process of connecting the through frame to the inner formwork. FIG. [Figure 17] FIG. [Figure 18] FIG. 4 is an enlarged cross-sectional view showing another example of a masking member. [Figure 19] FIG. 4 is an enlarged cross-sectional view showing another example of a masking member. [Figure 20] An exploded oblique view of a frame unit in a construction method according to another embodiment of the present invention. [Figure 21] 21 is a plan view of the receiving frame unit shown in FIG. 20. [Figure 22] 13 is a cross-sectional oblique view showing a groove body in which a receiving frame is installed according to a method for constructing a receiving frame for a grating in another embodiment of the present invention. FIG. [Figure 23]FIG. 1 is a partially enlarged perspective view showing a state in which concrete has adhered to the surface of a receiving frame constructed by a conventional construction method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below are merely examples for embodying the technical idea of ​​the present invention, and are not limited to the following things or methods. In addition, this specification never specifies the members shown in the claims to be members of the embodiments. In particular, the dimensions, materials, shapes, and relative positions of the components described in the embodiments are merely explanatory examples, and are not intended to limit the scope of the present invention, unless otherwise specified. Note that the size and positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation. Furthermore, in the following explanation, the same names and symbols indicate the same or similar members, and detailed explanations will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured as a form in which multiple elements are composed of the same member, and one member serves multiple elements, or conversely, the function of one member can be shared by multiple members.

[0029] (Embodiment 1) The construction method of the grating frame according to one embodiment of the present invention is a construction method for fixing a frame 2 for placing a grating 1 to the upper part of a side wall part 11 of a groove body 10 such as a road gutter, a cross gutter, or a drainage ditch of a factory, which is formed in a groove shape with concrete, as shown in Figs. 1 and 2. The construction method of the grating frame includes an outer formwork arrangement step of arranging an outer formwork 4 that forms the outer surface of the side wall part 11, a frame connection step of connecting the frame 2 to the inner formwork 3 that forms the inner surface of the side wall part 11, an inner formwork arrangement step of arranging the inner formwork 3 inside the outer formwork 4 and arranging the frame 2 in a predetermined position, a concrete pouring step of filling a filling space 19 formed between the outer formwork 4, the inner formwork 3, and the frame 2 with unhardened concrete to form a side wall part 11 to which the frame 2 is fixed, and a removal step of removing the inner formwork 3 and the outer formwork 4 after the poured concrete hardens. The receiving frame 2 connected to the inner formwork 3 in the receiving frame connecting step includes angle members 21 that are extended in the extension direction of the side wall portion 11 and arranged opposite each other, and the cross section of the angle member 21 is L-shaped, and includes a horizontal portion 22 that extends in the length direction and a vertical portion 23 that is connected upward in a vertical position along one side edge of the horizontal portion 22, and is connected to the inner formwork 3 so that the other side edge of the horizontal portion 22 is in a position approaching the outer surface of the inner formwork 3, and a groove-shaped space 24 is formed between the vertical portion 23 and the inner formwork 3. Furthermore, the construction method of the receiving frame for grating includes a masking step, which is a step prior to the concrete pouring step, of preparing a masking member 5 having an outer shape that follows the inner shape of the groove-shaped space 24, fitting the masking member 5 into the groove-shaped space 24, and bringing the masking member 5 into close contact with the inner surface of the vertical portion 23 to cover the inner surface of the angle member 21.

[0030] The construction method for the grating receiving frame can further comprise the gutter 10 being composed of an existing gutter 14 having a pair of side wall bases 13 erected on both sides of the bottom plate 12, and a poured concrete section 15 formed by pouring concrete on the existing gutter 14. This construction method includes a step of preparing the existing gutter 14 as a step preceding the step of arranging the inner formwork, in which the pair of inner formworks 3 are fixed to the inner surface of the pair of side wall bases 13 of the existing gutter 14 and the angle member 21 is arranged in a fixed position above the side wall bases 13, and in the step of pouring concrete, the poured concrete section 15 is formed with concrete filled in the filling space 19, and the poured concrete section 15 is integrally connected to the side wall base 13 to form the side wall section 11.

[0031] Each step of the construction method for a grating frame according to one embodiment of the present invention will be described in detail below. The construction method described below illustrates a method for fixing a grating frame 2 to a groove body 10 that is composed of an existing groove body 14 having a pair of side wall bases 13 on both sides of a bottom plate portion 12, and a poured concrete portion 15 formed by pouring concrete on the existing groove body 14.

[0032] [Preparation process for existing trench body] As a preparation process for the existing gutter 14, an existing gutter construction process is shown, in which the existing gutter 14 is newly constructed at the construction site. In this construction process, the existing gutter 14 is constructed through the following steps shown in Figs. 3 to 5. (1) As part of the topographical work, a construction area 70 is excavated by root cutting work, crushed stone 71 is laid down, compacted with a roller, and then basal concrete 72 is poured. (2) After the poured concrete has hardened, markings are made on the basin concrete 72, and reinforcement work is carried out based on this. In the reinforcement work, a plurality of reinforcing bars 73 are crossed vertically and horizontally at predetermined intervals in a horizontal plane to arrange the reinforcing bars 73 to be embedded in the bottom plate portion 12 that forms the base of the groove body 10, and the reinforcing bars 73 to be embedded inside the side wall base portions 13 formed on both sides of the bottom plate portion 12 are raised and arranged. (3) An outer formwork 4 for forming the outer surface of the side wall base 13 and an inner formwork 3 for forming the inner surface of the side wall base 13 are installed along the markings drawn on the basing concrete 72. These formworks are installed in predetermined positions in a vertical orientation. (4) Unhardened concrete is poured into the formwork to form the bottom plate 12 and the side wall base 13. At this time, the top surface of the bottom plate 12 is smoothed and flattened with a trowel. (5) After the concrete has sufficiently hardened, the inner form 3 is removed. At this time, the outer form 4 is left in place without being removed. This is because the outer form 4 used when molding the side wall base 13 of the existing trench 14 can also be used as the outer form 4 for forming the poured concrete portion 15 described later, simplifying the outer form placement process. Through the above steps, the existing groove body 14 is constructed.

[0033] [Outer formwork placement process] In the outer formwork placement step, the outer formwork 4 that forms the outer surface of the side wall portion 11 is placed at a predetermined position. The outer formwork 4 is a formwork that forms the outer surface of the side wall portion 11 and is composed of a plate-shaped panel. A wooden flat panel (commonly known as plywood) is generally used for the outer formwork 4. When constructing the side wall portion 11 by providing a poured concrete portion 15 on the side wall base portion 13 of the existing groove body 14, the outer formwork 4 is placed along the outer surface of the side wall base portion 13. The outer formwork 4 is placed in a vertical position so that the inner surface becomes the forming surface that forms the side wall portion 11, and is fixed in a predetermined position at the installation location via a fixing member 41 placed on the outside. The outer formwork 4 is a formwork for defining the outer surface of the poured concrete portion 15 to which the receiving frame 2 is fixed, and therefore has a height that protrudes above the upper end of the receiving frame 2 that is placed above the side wall base portion 13.

[0034] Here, as described above, when molding a new sidewall base 13 at the construction site, the outer formwork 4 used in the existing trench construction process can be left in the installed state without being removed, thereby making it possible to perform the outer formwork placement process. Therefore, even when constructing a sidewall base 13 that is lower in height than the sidewall 11 in the existing trench construction process described above, the outer formwork 4 installed in the existing trench construction process can be used as the outer formwork placement process by setting the height of the outer formwork 4 to a height at which the sidewall 11 can be formed.

[0035] [Frame connection process] In the frame connecting step, the frame 2 is connected and fixed to the inner formwork 3 that forms the inner surface of the side wall portion 11. The frame 2 for the grating 1 is a frame member for placing the grating 1 at a fixed position in the groove body 10, and as shown in Figs. 1 and 10, includes a pair of angle members 21 that extend in the extension direction of the side wall portion 11. The pair of angle members 21 are arranged so as to face each other inside the upper end of the side wall portion 11, and a mounting recess 29 for placing the side edge portion of the grating 1 is formed. The angle member 21 has an L-shaped cross section and includes a horizontal portion 22 that extends in the length direction and a vertical portion 23 that is connected upward in a vertical position along one side edge of the horizontal portion 22. The total length (L) of the angle member 21, the width (W) of the horizontal portion 22, and the height (H) of the vertical portion 23 are changed depending on the specifications of the grating 1 to be installed and the installation location, but for example, the total length (L) of the angle member 21 is 20 to 150 cm, the width (W) of the horizontal portion 22 is 20 to 150 mm, preferably 40 to 80 mm, and the height (H) of the vertical portion 23 is 20 to 200 mm, preferably 40 to 90 mm. The angle member 21 shown in the figure has, as an example, a total length (L) of 100 cm, an overall width of 60 mm, an overall height of 66 mm, a width (W) of the horizontal portion 22 minus the thickness of the metal plate of 54 mm, and a height (H) of the vertical portion of 60 mm. As mentioned above, the dimensions of the angle member 21 vary depending on the specifications of the grating 1 and the installation location, but in particular, as for the height of the angle member 21, another example is one in which the overall height is 71 mm and the height (H) of the vertical part minus the thickness of the metal plate is 65 mm. In this frame connecting process, the angle member 21 of the frame 2 is connected to the inner formwork 3 so that the other side edge of the horizontal part 22 is in a position approaching the outer side surface of the inner formwork 3. With the angle member 21 connected to the inner formwork 3, a groove-shaped space 24 with a rectangular cross section is formed between the vertical part 23 and the inner formwork 3.

[0036] Here, the receiving slots 2 include the following types: (1) Frame As shown in Fig. 10 and Fig. 11, the square frame 2A has a rectangular frame shape formed by connecting both ends of a pair of angle members 21 arranged opposite to each other with a connecting plate 25. A frame 2 of this shape has the feature that a pair of opposing angle members 21 can be arranged in an accurate position and with a predetermined interval. For example, a frame 2 of this shape is used as a frame 2 for installing a grating 1 that is arranged alone in an opening opened at a predetermined position of a side gutter or drainage ditch whose upper opening of the gutter body 10 is closed with a concrete cover. The frame 2 of this shape is arranged and connected so that the inner edges of the horizontal parts 22 of each angle member 21 approach the outer surfaces of a pair of inner formworks 3. The receiving frame 2, which is the four-sided frame 2A, can be connected to a fixed position on the inner formwork 3 via dedicated fixing brackets, etc., but the simplest connection method, although not shown, is to provide a protruding member such as a nail that protrudes outward on the outer surface of the inner formwork 3, and support the angle member 21 in a fixed position on the outer surface of the inner formwork 3 with the horizontal part 22 of the angle member 21 placed on this protruding member.

[0037] (2) Through frame As shown in Fig. 12, the through frame 2B is composed of only a pair of angle members 21 arranged opposite each other, without connecting both ends of the angle members 21 with a connecting plate. A receiving frame 2 of this shape is used, for example, as a receiving frame 2 for arranging gratings 1 in a continuous line along the extension direction of the upper opening of the groove body 10. Therefore, the edges of the angle members 21 constituting the through frame 2B are connected to the edges of the through frames 2B arranged adjacent to each other, or the open edges of the angle members constituting the three-sided frame described below are connected. The angle members 21 connected in a straight line at their opposing edges are arranged so that there is no difference in height between the horizontal parts 22 or the left and right positions of the vertical parts 23 are not shifted.

[0038] The angle member 21 constituting the through frame 2B is fixed to the outer surface of the inner formwork 3 via a fixing device 36. Figures 13 to 16 show an example of a fixing device 36 for fixing the angle member 21 to the outer surface of the inner formwork 3. The fixing device 36 shown in the figures includes a support portion 36A having a support surface 36a that supports the horizontal portion 22 of the angle member 21 from below and an abutment surface 36b that abuts against the outer surface of the inner formwork 3, a fixing plate portion 36B that extends upward from the support surface 36a along the abutment surface 36b at one end of the support portion 36A on the inner formwork 3 side, and a holder portion 36C that is an engagement piece that is arranged at the tip side of the support portion 36A and away from the inner formwork 3, protruding upward. The fixing plate portion 36B of this fixing device 36 is fixed at a fixed position on the inner form 3 via the set screw 37, and the horizontal portion 22 is placed on the support surface 36a of the support portion 36A with the vertical portion 23 disposed inside the holder portion 36C to hold the angle member 21 in a fixed position relative to the inner form 3. After the concrete filled between the outer form 4, the inner form 3, and the receiving frame 2 has hardened, the inner form 3 is removed from the fixing device 36, and the fixing plate portion 36B is then removed, and the angle member 21, which is L-shaped in cross section, is disposed in a fixed position on the side wall portion 11.

[0039] (3) Three-sided frame Although not shown, the three-sided frame is a U-shaped frame formed by connecting one edge of a pair of opposing angle members with a connecting plate. This type of frame is used as a frame for arranging gratings in a continuous line along the extension direction of the upper opening of the groove body, with the free edges of the opposing pair of angle members connected to a through frame or three-sided frame. This three-sided frame is also fixed to the outer surfaces of the pair of inner formworks via fasteners.

[0040] The material of the frame 2 is not particularly limited, but may be, for example, a metal such as iron, stainless steel, or aluminum. The frame 2 may also be made of FRP. The material of the frame 2 may be appropriately selected depending on the construction site, etc.

[0041] (Anchor member 26) Furthermore, the receiving frame 2 shown in Figs. 10 and 11 has an anchor member 26 fixed to the outer surface of the angle member 21. The anchor member 26 shown in the figures is a metal rod bent into a U-shape, and both ends are fixed to the outer surface of the vertical part 23 by welding or the like, with the U-bent part protruding downward from the horizontal part 22. The receiving frame 2 shown in the figures has multiple anchor members 26, which are fixed at intervals in the length direction of the angle member 21. In this way, by providing multiple anchor members 26, the receiving frame can be reliably fixed to the side wall part 11 formed of concrete by embedding the anchor members 26 in the side wall part 11. In particular, the anchor member 26 shaped to embed the U-bent part in concrete has the advantage that the concrete can be guided to the inside of the U-bent part and firmly embedded and fixed. However, the anchor part is not limited to the above structure, and various shapes that can fix the receiving frame 2 to the side wall part 11 can be adopted.

[0042] (Threaded part 27) Furthermore, the angle member 21 shown in FIG. 10 has a threaded portion 27 protruding from the upper surface of the horizontal portion 22. This threaded portion 27 is for fixing the grating 1 placed on the receiving frame 2, and is provided in a position facing the screw insertion portion 1a provided at the corner of the grating 1. The threaded portion 27 can be fixed by welding a threaded rod with a male thread on the outer circumferential surface to the upper surface of the horizontal portion 22, but can be simply provided using a bolt 45 as shown in FIGS. 6 to 9. The threaded portion 27 shown in the figure is provided by inserting a bolt 45 upward from the lower surface side of the horizontal portion 22 into a through hole 28 opened in the horizontal portion 22, and then welding the head of the bolt 45 to the lower surface of the horizontal portion 22. The receiving frame 2 shown in the figure has threaded portions 27 at both ends of the opposing angle members 21, and the grating 1 is fixed in place by inserting the bolt 45 into the screw insertion portion 1a provided at the four corners of the grating 1. A nut member 46 is screwed into the tip of the threaded portion 27 inserted into the screw insertion portion 1a of the grating 1, and the grating 1 is fixed in a fixed position on the receiving frame 2. However, the receiving frame does not necessarily need to be provided with a threaded portion, and it can also be a receiving frame without a threaded portion. The receiving frame is determined according to the installation location where the grating will be installed. In other words, the presence or absence of a threaded portion is appropriately selected depending on the type of grating to be installed at the installation location.

[0043] [Formwork unit formation process] In the frame connecting step, the frame 2 is connected to the inner formwork 3. The inner formwork 3 shown in FIG. 11 and FIG. 12 is provided as a formwork unit 30 formed in a rectangular tube shape by connecting both ends of a pair of inner formworks 3 with a connecting plate 31. The inner formwork 3 is a formwork that forms the inner surface of the side wall portion 11, and is composed of a plate-shaped panel. A wooden concrete panel (commonly known as plywood) is generally used for the inner formwork 3. In the formwork unit forming step, the inner formwork 3 and the connecting plate 31 that are arranged opposite each other are fixed to the corner member 32 arranged inside the corner portion with a set screw or the like to form the formwork unit 30 in a rectangular tube shape. According to the structure in which the pair of inner formworks 3 are arranged as the formwork unit 30 in this way, there is an advantage that the pair of inner formworks 3 can be simply and easily arranged in a fixed position while maintaining a predetermined distance between them.

[0044] [Frame unit formation process] The rectangular cylindrical formwork unit 30 has a receiving frame 2 connected to a fixed position on the outside to form the receiving frame unit 20. As shown in Figures 11 and 12, the receiving frame unit 20 is formed by fixing angle members 21 to the outer surfaces of a pair of inner formwork frames 3 of the rectangular cylindrical formwork unit 30 in a receiving frame unit formation process. This receiving frame unit formation process allows the pair of angle members 21 to be easily and reliably positioned on the outer surfaces of the pair of inner formwork frames 3.

[0045] As shown in Fig. 11, the frame 2, which is a four-sided frame 2A, is arranged along the outer periphery of the rectangular cylindrical formwork unit 30, and is connected to the formwork unit 30 in a fixed position with the horizontal portion 22 of the angle member 21 placed on a protruding member such as a nail (not shown) protruding from the outer surface of the inner formwork 3 to form the frame unit 20. As shown in Fig. 12, the frame 2, which is a through frame 2B, is fixed via a fastener 36 to the outer surface of a pair of inner formworks 3 of the formwork unit 30 formed in a rectangular cylindrical shape to form the frame unit 20. The frame 2, which is a three-sided frame, is also fixed via a fastener to the outer surface of a pair of inner formworks of the formwork unit formed in a rectangular cylindrical shape to form the frame unit.

[0046] [Inner formwork placement process] In the inner formwork placement step, the inner formwork 3 which forms the inner surface of the sidewall 11 is placed at a predetermined position inside the outer formwork 4. When constructing the sidewall 11 by providing a poured concrete section 15 on the sidewall base 13 of the existing trench 14, the inner formwork 3 is fixed to the inner surface of the sidewall base 13. The inner formwork 3 is a formwork for defining the inner surface of the poured concrete section 15 to which the receiving frame 2 is fixed, and is placed in a vertical position so that its outer surface becomes the forming surface which forms the poured concrete section 15. At this time, the inner formwork 3 is positioned so that the angle member 21 connected to the outside is placed at a fixed position above the sidewall base 13.

[0047] In a structure in which the inner formwork 3 is disposed as a frame unit 20 on the sidewall base 13, as shown in Fig. 6, a cylindrical frame unit 30 is disposed between a pair of sidewall bases 13, with the outer surfaces of each of the pair of inner formworks 3 being disposed close to the inner surfaces of the pair of sidewall bases 13. Therefore, the cylindrical frame unit 30 is formed so that the distance (D) between the outer surfaces of the pair of inner formworks 3 is approximately equal to or slightly smaller than the distance (W) between the inner surfaces of the pair of sidewall bases 13. The cylindrical frame unit 20 disposed between the pair of sidewall bases 13 is positioned so that the angle member 21 disposed on the upper part of the frame unit 30 is disposed at a predetermined position above the sidewall base 13, and the lower part of the frame unit 30 is fixed to the inner surface of the sidewall base 13 by nailing or the like, and disposed at a predetermined position.

[0048] In the above-described inner form placement process, the inner form 3 to which the receiving frame 2 is connected in the receiving frame connecting process is placed at the side wall base 13, but the receiving frame connecting process can also be performed as a subsequent process to the inner form placement process, and after the inner form 3 is placed at the side wall base 13, the receiving frame 2 can be fixed in a fixed position on the inner form 3.

[0049] As described above, with the outer form 4 placed outside the sidewall base 13 and the inner form 3 connected to the receiving frame 2 placed inside the sidewall base 13, a filling space 19 into which unhardened concrete is filled is formed between the outer form 4, the inner form 3, and the receiving frame 2. Unhardened concrete is filled into this filling space 19 in the concrete pouring process described below.

[0050] As described above, when the angle member 21 is connected to the outer surface of the inner formwork 3, a groove-shaped space 24 is formed between the vertical part 23 of the angle member 21 and the inner formwork 3. However, this groove-shaped space 24 causes various problems when unhardened concrete flows over the vertical part 23 during the concrete pouring process and the leveling process described below. For example, the concrete flowing into the groove-shaped space 24 adheres to the inner surface of the angle member 21, making the appearance worse, and removing the adhered concrete takes time and effort, and may cause installation failure of the grating 1. In order to prevent such problems, the construction method of the present invention includes a masking process in which a masking member 5 is placed in the groove-shaped space 24 to cover the inner surface of the angle member 21 as a pre-concrete pouring process.

[0051] [Masking process] The masking step includes a step of preparing a masking member 5 to be placed in the groove-shaped space 24, and a step of fitting the masking member into the groove-shaped space. In the step of preparing the masking member 5, a masking member 24 to be placed in the groove-shaped space 24 in a state satisfying predetermined conditions is prepared.

[0052] (Masking material 5) The masking member 5 is formed in a long and thin rectangular column shape so that it can be inserted into the groove-shaped space 24 in a fitted state as shown in Figs. 11, 12, and 17, and has an outer shape that follows the inner shape of the groove-shaped space 24. When the masking member 5 is fitted into the groove-shaped space 24, it is structured so that it is inserted between the inner formwork 3 and the vertical part 23 without any gaps by adhering to the inner surface of the vertical part 23. The angle member 21 arranged outside the inner formwork 3 may have some error in the distance between the vertical part 23 and the inner formwork 3. Therefore, it is desirable that the masking member 5 can be arranged without any gaps in the groove-shaped space 24 while absorbing the error. Taking these into consideration, the masking member 5 is formed so that the total length (y) is approximately equal to or slightly larger than the total length (L) of the angle member 21 and the width (x) is approximately equal to or slightly larger than the width (W) of the horizontal part 22 of the amble member 21.

[0053] The masking member 5 can be integrally molded from, for example, a resin foam. In particular, by forming it into a closed cell structure, excellent water resistance can be realized. A masking member molded from a resin foam having water resistance in this way has the advantage that even if concrete adheres to the surface, it can be easily removed and can be used repeatedly. As the resin material used for the resin foam, a polymer material based on polyolefin, polyurethane (PUR), or polystyrene (PS) can be used. As the polyolefin resin, polyethylene (PE), polypropylene (PP), or ethylene vinyl acetate copolymer resin (EVA) can be used. In addition, polyvinyl chloride (PVC) or phenolic resin (PF) can also be used. The masking member 5 integrally molded from the above resin foam has physical properties that allow the entire masking member to be elastically deformed, so that it can be ideally pressed into the groove-shaped space 24 formed between the vertical part 23 of the angle member 21 and the inner formwork 3. The masking member 5 pressed into the groove-shaped space 24 in this way is arranged in a state of close contact with the inner surface of the vertical part, covering the inner surface of the angle member 21 and protecting it from concrete.

[0054] Furthermore, the masking member 5 may have another structure that allows it to be fitted into the groove-shaped space 24 without any gaps. For example, as shown in FIG. 18, the masking member 5 may have a structure in which an elastically deforming portion 53 that elastically deforms in the width direction of the groove-shaped space 24 is provided for a columnar main body member 52. The masking member 5 shown in FIG. 18 has a structure in which the elastically deforming portion 53 is provided on the side surface of the main body member 52 formed of a hard member, so that the masking member 5 can be pressed into the groove-shaped space 24 without any gaps. In this case, wood or wood processed products, steel or steel processed products, other metal processed products, hard plastics, hard rubber materials, etc. can be used for the hard member that constitutes the main body member 52. In addition, rubber-like elastic bodies, soft plastics, resin foams having closed or open cells, etc. can be used for the elastically deforming portion 53 fixed to the side surface of the main body member 52. The masking member 5 of this structure can also be pressed into the groove-shaped space without any gaps while the elastically deforming portion 53 provided on the side surface is elastically deformed. Furthermore, as shown by the chain line in the figure, the masking member with this structure can have the side surface of the main body member 52 as an inclined surface that gradually narrows downward. This masking member 5 has a structure in which the lower end is narrower than the width (W) of the groove-shaped space 24 to enable smooth insertion, while the upper end is wider than the width (W) of the groove-shaped space 24, allowing it to be pressed into the groove-shaped space 24 without any gaps near the opening of the groove-shaped space 24. Although not shown, this masking member can also have the main body member 52 with a uniform width, with the thickness of the elastic deformation portion 53 provided on the side surface being thicker at the top and gradually thinner toward the bottom.

[0055] Furthermore, as shown in Figs. 6 to 11 and 17, the masking member 5 that can be attached to the receiving frame 2 having a plurality of threaded portions 27 protruding upward from the horizontal portion 22 has a hole 5a for guiding the threaded portion 27 at a position opposite the threaded portion 27. The hole 5a is a recess for inserting and covering the threaded portion 27, and its depth is made larger than the protruding amount of the threaded portion 27 and its inner diameter is made larger than the outer diameter of the threaded portion 27 so that the threaded portion 27 can be inserted without difficulty. The masking member 5 shown in the figure has holes 5a at both ends of the lower surface, and the threaded portion 27 provided in the angle member 21 has some error in its position depending on the grating 1 to be attached. Therefore, even if the position of the threaded portion 27 of the receiving frame 2 is slightly different, the inner diameter of the hole 5a is made large so that the threaded portion 27 can be reliably guided to the hole 5a. The hole 5a shown in the figure is provided so that its center is located on the center line in the width direction, and the inner diameter of the hole is, for example, 1.5 to 2 times the outer diameter of the screw part 27. Furthermore, the hole of the masking member can be made into an elongated hole shape or a groove shape so that even if the screw part is located at a different position depending on the receiving frame, it can be effectively covered while absorbing the error. As described above, by using a masking member 5 having a hole 5a at a position opposite to the receiving frame 2 having the screw part 27, the screw part 27 can be guided to the hole 5a and placed in the groove-shaped space 24. However, the masking member does not necessarily need to have a hole, and a masking member without a hole can be placed for a receiving frame without a screw part. Also, a masking member with a hole can be placed for a receiving frame without a screw part.

[0056] The masking member 5 inserted into the groove-shaped space as described above is preferably designed so that its upper surface height is slightly lower than the upper end of the vertical portion 23 of the angle member 21. That is, the height (h) of the masking member is made smaller than the height (H) of the vertical portion. This is to facilitate smooth movement of the trowel along the upper end of the vertical portion 23 of the angle member 21 when leveling the upper surface of the concrete after the unhardened concrete has been poured. The upper surface level of the masking member 5 is, for example, 1 to 10 mm, preferably 5 to 8 mm, lower than the upper end level of the vertical portion 23. If the upper surface level of the masking member 5 is too lower than the upper end level of the vertical portion 23, there is a risk that a portion of the concrete that protrudes beyond the upper end of the vertical portion 23 and protrudes inward during the trowel leveling operation will adhere to the inner surface of the vertical portion 23, thereby deteriorating the appearance. Therefore, such a problem can be suppressed by reducing the height difference between the upper surface level of the masking member 5 and the upper end level of the standing wall 23.

[0057] (Spacer member 51) Furthermore, the height of the vertical part of the angle member may differ depending on the specifications of the grating 1 and the installation conditions of the grating 1. For example, when a high-height grating is installed or when a rubber for vibration prevention is interposed between the grating and the horizontal part, an angle member with a high vertical part is used. When such an angle member is used, the depth of the groove-shaped space becomes deep, so in order to optimize the height of the top surface position of the masking member, it is necessary to prepare a masking member with a high height. In such a case, preparing masking members with different heights is inefficient in terms of cost and storage of the members. Therefore, in such a case, the masking member 5 shown in FIG. 19 is provided with a spacer member 51 in order to correspond to the groove-shaped space 24 with different depths while using masking members of the same size.

[0058] The masking member 5 shown in FIG. 19 includes a main body portion 50 to be press-fitted into the groove-shaped space 24, and a spacer member 51 to be laminated between the main body portion 50 and the horizontal portion 22. The spacer member 51 has an outer shape that conforms to the inner shape of the groove-shaped space 24 in a plan view, and is molded to a uniform thickness. In this manner, the upper surface height of the masking member 5 can be adjusted by first disposing the spacer member 51 at the bottom of the groove-shaped space 24 and then press-fitting the main body portion 50 from above. At this time, the spacer member 51 can be easily inserted by making its width (s) preferably slightly smaller than the width (W) of the groove-shaped space 24, while the width (x) of the main body portion 50 can be made approximately equal to or slightly larger than the width (W) of the groove-shaped space 24, so that the main body portion 50 can be press-fitted into the groove-shaped space 24 and the spacer member 51 can be sandwiched and held between the horizontal portion 22 and the main body portion 50. In this way, by stacking the spacer member 51 between the main body portion 50 and the horizontal portion 22, the height of the upper surface of the masking member 5 can be easily adjusted according to the height of the vertical portion 22. Note that the spacer member 51 shown in Fig. 19 also has a hole 5b provided opposite the screw portion 27 protruding from the horizontal portion 22. This hole 5b is a through hole that allows the screw portion 27 to pass through.

[0059] As described above, by providing a masking step of placing the masking member 5 in the groove-shaped space 24 as a step preceding the concrete pouring step, the inner surface of the angle member 21 is covered, and the concrete protruding from the vertical portion 23 can be reliably prevented from directly adhering to the surface of the angle member 21. Here, the step of placing the masking member 5 in the groove-shaped space 24 can be a step subsequent to the inner formwork placement step, but preferably, it is a step subsequent to the above-mentioned frame unit formation step, and the masking member 5 can be placed in the groove-shaped space 24 of the frame unit 20 as a step preceding the inner formwork placement step. Thereafter, in the inner formwork placement step, the frame unit 20 to which the masking member 5 is attached is placed between the pair of side wall bases 13, and the angle member 21 covered with the masking member 5 is placed in a fixed position above the side wall bases 13.

[0060] [Concrete pouring process] In the concrete pouring process, the filling space 19 formed between the outer formwork 4, the inner formwork 3, and the receiving frame 2 is filled with unhardened concrete to form the side wall portion 11 to which the receiving frame 2 is fixed. As shown in the figure, the unhardened concrete is supplied from between the vertical portion 23 of the receiving frame 2 and the outer formwork 4 to fill the entire filling space 19. In addition, in the leveling process, the upper surface of the unhardened concrete filled in the filling space is leveled with a trowel along the upper end of the vertical portion 22 to make it flat. In this leveling work, the concrete that protrudes beyond the upper end of the vertical portion 23 adheres to the upper surface of the masking member 5, but can be easily removed after the concrete hardens. In addition, in this concrete pouring process, there is a risk that the slag that seeps out from the gap between the angle member 21 and the inner formwork 3 will adhere to the surface of the horizontal portion, but since this slag is close to the supernatant liquid of the unhardened concrete and does not contain aggregate, it can be easily removed by scraping with a spatula or the like after removing the masking member.

[0061] In this manner, the poured concrete portion 15 cast on top of the side wall base 13 of the existing groove body 13 is integrally connected to the side wall base 13 of the existing groove body 13 to form the side wall portion 11, and the anchor member 26 of the receiving frame 2 is embedded in this side wall portion 11 to fix the receiving frame 2 to the upper part of the side wall portion 11.

[0062] [Removal process] After the poured concrete has hardened, the inner formwork 3 and the outer formwork 4 are removed in the removal process. In this state, as shown in Fig. 9, a mounting recess 29 in which the grating 1 is placed is formed by the receiving frame 2 fixed onto the side wall portion 11 of the groove body 10 cast from concrete. The grating 1 is then set in this mounting recess 29. In the receiving frame 2 having a threaded portion 27, when the threaded portion 27 protruding from the horizontal portion 22 is inserted into the screw insertion portion 1a of the grating 1, a nut member is connected to the tip of the threaded portion and the grating is fixed in place.

[0063] (Embodiment 2) In the above embodiment 1, an example of constructing a frame for placing a grating with a rectangular outer shape has been shown, but the present invention can also construct a frame for use in a mass hole with a grating with a roughly square outer shape. In this construction method, the frame is constructed in the groove body by the following steps. (1) Preparation process for existing trench body (2) Outer formwork placement process (3) Receiver frame connection process (4) Inner formwork placement process (5) Masking process (6) Concrete pouring process (7) Removal process In the construction method according to the second embodiment, the same steps as those in the construction method according to the first embodiment will not be described.

[0064] In this construction method, the frame connecting process can include a preparation process for preparing frames on all four sides, a formwork unit forming process, and a frame unit forming process. [Preparation process for preparing the frame] As shown in Figs. 20 and 21, a four-sided frame 2D is prepared as the receiving frame 2 to be used for the mass hole, which is rectangular in plan view and has angle members 21 arranged on at least three sides. The four-sided frame 2D shown in the figures has a pair of first angle members 21 arranged parallel to each other, both ends of which are connected by a pair of second angle members 22, and the four sides are substantially square in plan view, with angle members 21 arranged on all four sides. The length of each side of this four-sided frame can be 20 to 100 cm, and the width (W) of the horizontal portion 22 and the height (H) of the vertical portion 23 can be within the above-mentioned range. However, although not shown, the receiving frame for the mass hole can also be a four-sided frame with angle members on three sides.

[0065] [Formwork unit formation process, frame unit formation process] In the form unit forming step, as shown in FIG. 21, both ends of a pair of inner formworks 3 are connected by a second inner formwork 3X to form a rectangular cylindrical formwork unit 30. Furthermore, in the receiving frame unit forming step, angle members 21 are fixed to the outer surfaces of the inner formwork 3 and the second inner formwork 3X of the formwork unit 30 to form the receiving frame unit 20. As shown in the figure, the receiving frame 2, which is a four-sided frame 2D, is inserted from above along the outer peripheral surface of the rectangular cylindrical formwork unit 30, and is connected to a fixed position of the formwork unit 30 in a state in which the horizontal portion 22 of the angle member 21 is placed on a protruding member 35 such as a nail protruding from the outer peripheral surface of the formwork unit 30, to form the receiving frame unit 20. At this time, a first angle member 21A is arranged on the outer surface of the inner formwork 3, and a second angle member 21B is arranged on the outer surface of the second inner formwork 3X. In this state, a channel-shaped space 24 is formed between the inner form 3 and the first angle member 21A, and between the second inner form 3X and the second angle member 21B.

[0066] [Masking process] The masking member 5 is placed in the groove-shaped space 24 of the frame unit 20 constructed as described above. The masking member 5 shown in the figure includes a first masking member 5A inserted into the groove-shaped space 24 formed between the inner formwork 3 and the first angle member 21A, and a second masking member 5B inserted into the groove-shaped space 24 formed between the second inner formwork 3X and the second angle member 21B. As described above, the first masking member 5A and the second masking member 5B have a width (x) that allows them to be pressed into the groove-shaped space 24. The first masking member 5A has a longer overall length than the second masking member 5B, so that it can be inserted without a gap into the rectangular groove-shaped space 24 formed around the frame unit 30. The first masking member 5A shown in the figure has a total length (y1) that is approximately equal to or slightly longer than the total length (L1) of the first angle member 21A, and the second masking member 5B has a total length (y2) that is approximately equal to or slightly longer than the total length (L2) of the second angle member 21B minus twice the width (x) of the first angle member 21A. This allows the second masking member 5B to be placed between the pair of first masking members 5A and press-fitted into the rectangular groove-shaped space 24 without any gaps. Furthermore, the first masking member 5A shown in the figure has a hole 5a for guiding the screw portion 27 provided in the horizontal portion 22 of the first angle member 21A.

[0067] [Concrete pouring process] As described above, the square frame 2D having the angle members 21 on all four sides is fixed by concrete poured in a concrete pouring process, but the state in which each angle member 21 is fixed to the concrete differs depending on the installation location of the grating, etc. Here, as an example, as shown in Fig. 22, a process is shown in which a first angle member 21 is arranged along the extension direction of the side wall portion 11 and fixed to the upper end portion of the side wall portion 11, and a second angle member 21B is arranged across the opposing side wall portion 11 and fixed to the end portion of the lid portion 18 that closes the upper opening of the groove body 10. The square frame 2D shown in Fig. 22 is fixed in place by the concrete that forms the upper portion of the groove body 10 in the wall portion forming process and lid portion forming process described below.

[0068] [Wall forming process] In the wall formation process, similar to the concrete pouring process of the above-mentioned embodiment 1 (see Figures 7 and 8), unhardened concrete is filled into the filling space 19 formed between the outer formwork 4, the inner formwork 3, and the receiving form 2, and the poured concrete portion 15 is integrally connected to the side wall base 13 to form the side wall portion 11, and the first angle member 21A is fixed to the side wall portion 11.

[0069] [Lid formation process] In the lid forming process, the bridging member 16 is placed across the opposing side wall bases 13, and then unhardened concrete is poured on the bridging member 16 to form the lid 17 that closes the upper opening of the gutter body 10. The bridging member 16 can be, for example, a concrete panel or a metal plate having a predetermined thickness. The bridging member 16 is placed with both sides placed on the upper surfaces of the opposing side wall bases 13 to close the upper opening of the existing gutter body 14. The bridging member 16 that closes the upper opening of the existing gutter body 14 is placed in a state where multiple pieces are connected to close the upper opening over the length direction of the side wall base 13. Furthermore, the bridging member 16 that is placed adjacent to the four-sided frame 2D is placed with its edge close to the outer surface of the second inner formwork 3X. In this state, a second filling space 18 is formed between the second inner formwork 3X, the second angle member 21B, and the bridging member 16. After placing reinforcing bars on the bridging members 16 placed on the existing trench body 14, unhardened concrete is poured on the bridging members 16 to form a lid 17 that closes the upper opening of the trench body 10. The unhardened concrete poured on the bridging members 16 flows to the outer surface of the second inner formwork 3X and fills the second filling space 18 to form the lid 17, and the second angle member 21B is fixed to the lid 17.

[0070] Furthermore, in the wall forming process and the lid forming process, as a leveling process, the upper surface of the poured unhardened concrete is leveled with a trowel along the upper end of the vertical portion 22 to make it flat. In this leveling work, the concrete that has overflowed beyond the upper ends of the first angle member 21A and the second angle member 21B and protruded inside the frame 2D on four sides adheres to the upper surfaces of the first masking member 5A and the second masking member 5B, but can be easily removed after the concrete has hardened. In addition, in the wall forming process, there is a risk that slag that has seeped out from the gap between the first angle member 21A and the inner formwork 3 will adhere to the surface of the horizontal portion, or in the lid forming process, there is a risk that slag that has seeped out from the gap between the second angle member 21B and the second inner formwork 3X will adhere to the surface of the horizontal portion. However, this slag is similar to the supernatant liquid of unhardened concrete and does not contain aggregate, so it can be easily removed by scraping with a spatula or the like after removing the masking members.

[0071] [Removal process] After the poured concrete has hardened, the inner form 3, the second inner form 3X, and the outer form 4 are removed in the removal process. In this state, as shown in Figure 22, a mounting recess 29 for placing the grating 1 is formed by the receiving frame 2 fixed to the mass hole of the groove body 10 cast with concrete. Then, the grating 1 is set in this mounting recess 29.

[0072] In the above example, an example was shown in which a bottom plate portion 12 and a pair of side wall base portions 13 provided on both sides of the bottom plate portion 12 were newly constructed at the construction site as the existing gutter body 14, but the present invention is not limited to a structure in which an existing gutter body 14 is newly constructed. It is also possible to use a gutter body 10 already constructed at the site, remove a predetermined area of ​​the upper part of the old gutter body 10, and use the lower part remaining after the upper part is removed as the existing gutter body 14, and provide a newly poured concrete part 15 for fixing the receiving frame 2 to the upper part of the existing gutter body 14, and form the side wall part 11 of the gutter body 10 with the side wall base portion 13 and the poured concrete part 15. In other words, a part of the existing gutter body 10 can be reused as the existing gutter body 14 as a repair work for the old gutter body 10. In this way, when removing the upper part of the existing gutter body 10 to make it the existing gutter body 14, a predetermined area of ​​the upper part of the existing gutter body 10 can be cut and removed using a cutting device such as a concrete cutter. Therefore, in this case, the preparation step for the existing groove body 14 is an upper region removing step of removing the upper region of the existing groove body 10.

[0073] [Step of removing upper region of existing groove body 10] The existing gutter 10 is the target for the installation of the receiving frame 2 on which the new grating 1 will be installed. The upper parts of the existing side walls of the concrete gutter 10 are cut and removed, and the remaining lower parts are made into the side wall base 13. In this process, for example, at the construction site, the existing grating 1 is removed, the area around the existing gutter 10 is excavated, and then a predetermined area of ​​the upper part of the pair of side walls of the existing gutter 10 is cut and removed with a cutting device. At this time, the old receiving frame 2 is also removed at the same time. Thereafter, the remaining lower part of the existing gutter 10 is made into the existing gutter 14, i.e., the remaining lower part of the existing side wall from which the upper area has been removed is made into the side wall base 13, and the new receiving frame 2 is placed and fixed above it. [Industrial Applicability]

[0074] The present invention can be suitably adopted as a method for constructing a receiving frame for mounting a grating to be installed in a groove such as a road gutter, a cross gutter, or a factory drainage gutter, and as a masking member used in this construction. [Explanation of symbols]

[0075] 1. Grating 1a…Screw insertion part 2…Acceptance slot 2A…Four-sided frame 2B...Through frame 2D…Four-sided frame 3…Inner frame 3X: Second inner frame 4...Outer formwork 5…Masking material 5A…First masking member 5B…Second masking member 5a...hole 5b…hole part 10...Groove body 11...Side wall 12…Bottom plate part 13...Side wall base 14...Existing groove body 15...Pouring concrete section 16...Bridge member 17...Lid part 18...Second filling space 19...filling space 20…Receiving unit 21...Angle member 21A…First angle member 21B...Second angle member 22…Horizontal part 23…Vertical part 24…Groove space 25…Connecting plate 26...Anchor member 27…Threaded part 28...Through hole 29…Mounting recess 30…Formwork unit 31...Connection plate 32…Corner parts 35...Protruding member 36…Fixing tool 36A…Support part 36a...support surface 36b…Abutment surface 36B…Fixed plate part 36C…Holder section 37…Set screw 41...Fixing member 45…Volts 46…Nut member 50…Main body 51...Spacer member 52...Main body member 53...Elastic deformation portion 70…Construction area 71...Crush 72…Waste concrete 73…Reinforced concrete 81...Concrete block 82…Masking tape

Claims

1. A method for constructing a grating frame, which fixes a frame for placing a grating to an upper portion of a side wall of a groove body formed in a groove shape with concrete, an outer form arranging step of arranging an outer form forming an outer surface of the side wall portion; a frame connecting step of connecting the frame to an inner formwork that forms an inner surface of the side wall portion; an inner form arranging step of arranging the inner form inside the outer form and arranging the receiving form in a predetermined position; a concrete pouring process for filling a filling space formed between the outer form, the inner form, and the receiving frame with unhardened concrete to form the side wall portion to which the receiving frame is fixed; and a removal step of removing the inner form and the outer form after the poured concrete has hardened. The receiving frame connected to the inner form in the receiving frame connecting step includes an angle member extended in the extension direction of the side wall portion, the angle member has an L-shaped cross section and includes a horizontal portion extended in the length direction and a vertical portion connected upward in a vertical position along one side edge of the horizontal portion, the other side edge of the horizontal portion is connected to the inner form so as to be in a position approaching the outer surface of the inner form, and a groove-shaped space is formed between the vertical portion and the inner form, A construction method for a receiving frame for a grating, comprising the steps of: preparing a masking member having an outer shape that conforms to the inner shape of the groove-shaped space; fitting the masking member into the groove-shaped space; and bringing the masking member into close contact with the inner surface of the vertical portion to cover the inner surface of the angle member, as a preliminary step to the concrete pouring step.

2. A method for constructing the grating frame according to claim 1, The angle member includes a plurality of threaded portions projecting upward from the horizontal portion, the masking member has a hole portion at a position opposite to the screw portion for guiding the screw portion, A method for constructing a receiving frame for a grating, in which, in the masking process, the masking member is inserted into the groove-shaped space while guiding the screw portion into the hole portion.

3. A method for constructing a grating frame according to claim 1 or 2, The masking member is A body portion press-fitted into the groove-shaped space; a spacer member laminated between the main body portion and the horizontal portion, A construction method for a receiving frame for a grating, in which the spacer member has an outer shape that follows the inner shape of the groove-shaped space when viewed in a plane, and is molded to a uniform thickness so as to adjust the upper surface height of the main body portion.

4. A method for constructing a grating frame according to claim 1 or 2, The masking member is integrally formed from a resin foam, A method for constructing a receiving frame for a grating, in which the masking member is elastically deformed and pressed into the groove-shaped space in the masking process.

5. A method for constructing a grating frame according to claim 1 or 2, The masking member has an elastic deformation portion that elastically deforms in a width direction of the groove-shaped space, A construction method for a grating frame in which, in the masking process, the elastic deformation portion is elastically deformed to press it into the groove-shaped space.

6. A method for constructing a grating frame according to claim 1 or 2, The groove body is composed of an existing groove body having a pair of side wall bases erected on both sides of a bottom plate portion, and a poured concrete portion formed by pouring concrete on the existing groove body, A step of preparing the existing trench body as a pre-step of the inner formwork arrangement step is included; In the inner formwork positioning step, a pair of inner formworks are fixed to the inner surfaces of the pair of side wall bases of the existing trench body, and the angle members are positioned in a fixed position above the side wall bases, A method for constructing a receiving frame for a grating, in which, in the concrete pouring process, the poured concrete section is formed with concrete filled in the filling space, and the poured concrete section is integrally connected to the side wall base to form the side wall section.

7. A method for constructing a grating frame according to claim 6, The frame connecting step includes: a form unit forming step of connecting both ends of the pair of inner forms with a connecting plate to form a rectangular tubular form unit; and a frame unit forming step of fixing the angle members to the outer surfaces of the pair of inner forms of the form unit to form a frame unit, The masking step is a step subsequent to the frame unit forming step and a step prior to the inner formwork arranging step, and the masking member is fitted into the groove-shaped space of the frame unit; A method of constructing a receiving frame for a grating, in which, in the inner formwork placement process, the receiving frame unit with the masking member attached is placed between the pair of side wall bases, and the angle member covered with the masking member is placed in a fixed position above the side wall bases.

8. A method for constructing a grating frame according to claim 1 or 2, The groove body is composed of an existing groove body having a pair of side wall bases erected on both sides of a bottom plate portion, and a poured concrete portion formed by pouring concrete on the existing groove body, A step of preparing the existing trench body as a pre-step of the inner formwork arrangement step is included; The frame connecting step includes: a preparation step of preparing a four-sided frame as the receiving frame, the four-sided frame being rectangular in plan view and having the angle members disposed on at least three sides; a form unit forming step of connecting both ends of the pair of inner forms with a second inner form to form a rectangular tubular form unit; and a frame unit forming step of fixing the angle members to the outer surfaces of the inner form and the second inner form of the form unit to form a frame unit, The masking step is a step subsequent to the frame unit forming step and a step prior to the inner formwork arranging step, and the masking member is fitted into the groove-shaped space of the frame unit; In the inner formwork placement step, the receiving frame unit to which the masking member is attached is placed inside the side wall base, and the angle member covered with the masking member is placed in a fixed position above the existing groove body, The concrete pouring step includes: a wall forming step of filling the filling space with unhardened concrete to integrally connect the poured concrete portion to the side wall base to form the side wall; A construction method for a receiving frame for a grating, comprising: placing a bridging member across the opposing side wall bases, pouring unhardened concrete on top of the bridging member, and filling a second filling space formed between the second inner formwork, the receiving frame, and the bridging member with unhardened concrete to form a lid to which the receiving frame is fixed, the lid forming step being to close an upper opening of the groove body.

9. A masking member used for construction of a grating frame for fixing a frame for placing a grating on the upper part of a side wall portion of a groove body formed in a groove shape with concrete, The receiving frame includes angle members extending in the extension direction of the side wall portion and arranged opposite each other, the angle members each having an L-shaped cross section and including a horizontal portion extending in the length direction and a vertical portion connected upward in a vertical position along one side edge of the horizontal portion, the masking member is fitted into a groove-shaped space formed between the vertical portion and the inner form in a state in which the receiving frame is connected to the inner form such that the other side edge of the horizontal portion approaches the outer side surface of the inner form forming the inner side surface of the side wall portion, The masking member has an outer shape that conforms to the inner shape of the groove-shaped space, and when inserted into the groove-shaped space, it adheres closely to the inner surface of the vertical portion to cover the inner surface of the angle member.

10. 10. The masking member according to claim 9, A masking member having a hole portion for guiding the threaded portions at a position opposite the threaded portions so that the masking member can be attached to the receiving frame having a plurality of threaded portions protruding upward from the horizontal portion.

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