Termite-proof foundation construction method and termite-proof foundation structure

Abstract

In the present invention, a means for joining together a base part formwork and a rising part formwork using a paper panel is rationalized, and a uniform termite-proof line is efficiently provided to a placing joint between a rising part (43) and earthen floor concrete (6). An intermediate part (12) of a paper panel (1) is folded along a lower frame member (34) of a steel panel (3), and an upper part (11) of the paper panel (1) is disposed upright along the outside surface of the steel panel (3), then folded downward, and provisionally fixed in a state of being engaged with the lower frame member (34) of the steel panel (3). A termite-proof surface (15) formed in advance on the paper panel (1) is positioned in accordance with the height of a placing joint location between the rising part (43) and the earthen floor concrete (6), and is embedded in the lower side of the earthen floor concrete (6) in a state of being bent along the lower corner part of the placing joint location.

Description

Title of the Invention TERMITE-PROOF FOUNDATION CONSTRUCTION METHOD AND TERMITE-PROOF FOUNDATION STRUCTURE Technical Field

[0001] The present invention relates to a termite-proof foundation construction method applicable to a strip footing of a house or the like, and also relates to a termite-proof foundation structure constructed by the termite-proof foundation construction method. Background Art

[0002] As a foundation structure for small and medium-sized buildings such as houses, a strip footing (continuous footing foundation) having an inverted T-shaped cross section is widely adopted, in which an erected part is provided on a base part buried underground. Generally, the formwork for constructing the strip footing is configured by combining a base part formwork and an erected part formwork. The applicant of the present invention has developed a foundation construction method using a steel panel (metal form) as an erected part formwork while using a permanent formwork made of synthetic resin having a substantially quadrant cross section as a base part formwork so that the construction quality of the formwork and the workability when placing / demolding concrete are both improved. This method is practically used now, and the applicant disclosed related techniques in Patent Documents 1 to 3 and the like.

[0003] Such a foundation construction method assumes that placing of the concrete is performed at one time from the base part to the erected part. Accordingly, it is necessary to rigidly connect an upper edge part of the base part formwork to a lower frame member of the erected part formwork before placing the concrete so as not to disassemble or uplift the base part formwork by pressure at the time of placing the concrete. Although Patent Documents 1 to 3 also propose, as connection means, presser metal fittings, support members, connection members and the like, there is still a room for further improvement of the above connection means in terms of construction time and costs.

[0004] Recently, as a result of higher consciousness concerning environmental problems, people have had reservations about burying the synthetic resin permanent formwork underground. Although certain kinds of permanent formworks made of biodegradable plastics are provided, some construction owners have negative opinions on even these products. Furthermore, the formworks made of biodegradable plastics have disadvantages in qualities and costs compared to the conventional resin formworks, which also makes the construction owners hesitate to choose the biodegradable formworks.

[0005] In the strip footing, the ground level (dirt floor) other than the foundation is exposed under the floor. Thus, in order to prevent moisture from the ground level, dirt floor concrete (damp proofing concrete) is placed in all the areas surrounded by the erected parts. However, if any gap remains in a construction joint between the dirt floor concrete and the erected part, termites may enter the dirt floor through this gap. Although the termite control agent is sprayed along the construction joint so as to block the invasion route (mudtubes) of the termites, this method is likely to result in an unstable construction quality because of variations in the application amount and / or application range, apart from the fact that it is already a timeconsuming work on the site.

[0006] A method for blocking mudtubes is also publicly known, in which termiteproof sheets are laid around the dirt floor concrete. For example, Patent Documents 4 to 6 propose various construction works to apply termite-proof sheets onto the construction joint between the dirt floor concrete and the erected part. Examples of the above termite-proof sheets are: a resin sheet material into which a termite control agent is kneaded; and a stainless mesh material having a mesh size through which the termites cannot pass. However, it is not so easy to accurately lay and temporarily fix the termiteproof sheets around the dirt floor concurrently with the formwork construction of the strip footing or after placing the concrete of the strip footing. Thus, there is also a room for improvement in terms of construction work and costs.

[0007] Taking into integral consideration both the problems of the above-described resin permanent formwork and of the termite-proof work to the side surfaces of the erected parts, an option emerges, in which a paper formwork material subjected to termite-proof treatment is used as a formwork that is a part buried underground. Patent Document 7 discloses an invention on a formwork of a base part, which is formed by a cardboard subjected to the termite-proof treatment by medical agents.

[0008] The formwork is configured to surround peripheral wall parts of the base part by a plate body made of cardboard. The joint parts of the plate bodies are fixed by the presser plates. In order to reinforce the plate body, a bar member for maintaining the width is bridged and fastened in the plate body, and furthermore falling prevention members are hung and attached onto outer sides the plate body. Thus, the base part is formed by placing concrete in the formwork. After curing the base part, a formwork for an erected part is assembled on the base part so that the erected part is formed by successively pouring the concrete in the formwork. Then, after the erected part is demolded, a range from the lower end of the erected part to the top end of the base part is also covered by a cover made of cardboard subjected to the anti-intersect treatment.

[0009] Although the cardboard formwork covering the peripheral walls and the top end of the base part is left in the ground, it is decomposed and assimilated in the soil in a relatively short time. Also, the formwork made of cardboard is light and thus suitable for the construction work, and furthermore has water retention characteristics that lead to a high curing effect. However, the cardboard formwork disclosed in Patent Document 7 does not have a configuration that allows simultaneous formation of the base part and the erected part, and its method for assembling is not so efficient. Thus, there is also a room for improvement in terms of workability. Prior Art Documents Patent Documents

[0010] Patent Document 1: JP H07-018860 A Patent Document 2: JP H08-020959 A Patent Document 3: JP 2023-008484 A Patent Document 4: JP 2002-371643 A Patent Document 5: JP 2003-056087 A Patent Document 6: JP 2003-247281 A Patent Document 7: JP H08-092968 A Summary of the Invention Problem to Be Solved by the Invention

[0011] The present invention was made in total consideration of the various problems of the above-described prior arts. An object of the present invention is to provide a termite-proof foundation construction method with high workability, in which a permanent formwork made of paper having a low environmental impact is used as a base part formwork of a strip footing so as to simplify connection means of the base part formwork and an erected part formwork, and furthermore to form a homogeneous termiteproof line on a construction joint between an erected part and a dirt floor concrete.

[0012] Another object of the present invention is to provide a termite-proof foundation structure constructed by the termite-proof foundation construction method. Means for Solving the Problem

[0013] In order to achieve the above object, a termite-proof foundation construction method of the present invention for forming a termite-proof line on a construction joint between a strip footing and a dirt floor concrete is provided, which uses a bendable paper panel for a base part formwork and a steel panel for an erected part formwork. The method includes the following steps [Step 1] to [Step 11]: [Step 1] subjecting a predetermined position of the paper panel in a height direction to a termite-proof treatment in advance so as to form a termiteproof surface extending on the paper panel in a width direction; [Step 2] forming the erected part formwork by vertically building the steel panel on an appropriate support member provided on a construction surface; [Step 3] stacking an intermediate part of the paper panel in the height direction on a lower frame member of the vertically built steel panel, and bending and laying the intermediate part along a shape of the lower frame member; [Step 4] erecting an upper part of the paper panel along an outer surface of the steel panel and thus folding back the upper part in a downward direction at a position where the upper part abuts a lower surface of a lateral rib provided on the outer surface, and engaging a folded-back upper side edge with the intermediate part bent and laid along the shape of the lower frame member of the steel panel so that the folded-back upper side edge is fixed to the steel panel; [Step 5] inclining a lower part of the paper panel so as to spread toward a bottom according to a shape of a base part of the strip footing, and fixing a lower side of the lower part to the construction surface so as to form the base part formwork; [Step 6] placing concrete in a space in a formwork surrounded by the base part formwork and the erected part formwork so as to form the base part and an erected part; [Step 7] removing, after curing the concrete, the intermediate part and the upper part of the paper panel from the steel panel by disengaging the engagement, and thus removing the steel panel; [Step 8] erecting the upper part of the paper panel along a side surface of the erected part after demolded, and temporarily fixing the upper part to the erected part; [Step 9] putting backfilling soil into a dirt floor space surrounded by the strip footing so as to bury the erected part up to an intermediate part thereof in the height direction, and then preparing a dirt floor surface such that the dirt floor surface is located at a region where the termite-proof surface of the paper panel exists; [Step 10] bending the upper part of the paper panel, which is exposed above the dirt floor surface, along the dirt floor surface such that the upper part is overlapped with the dirt floor surface; and [Step 11] placing the dirt floor concrete on the dirt floor surface.

[0014] In the termite-proof foundation construction method disclosed by the present invention, [Step 4] as described above further includes: bending a side edge part of the paper panel erected along the outer surface of the steel panel toward the outer surface of the steel panel such that the side edge part is pushed inside between the lateral rib and the lower frame member and that the upper part of the paper panel is fixed.

[0015] Furthermore, [Step 8] as described above includes: unfolding the side edge parts, which are bent, of the paper panels such that adjacent upper parts of the paper panels come into contact or overlap with each other.

[0016] Furthermore, [Step 5] as described above includes: bringing into contact or overlapping, with each other, the adjacent lower parts of the paper panels.

[0017] Also, in the termite-proof foundation construction method as described above, it is preferable to form a folding line in the paper panel in advance, in a position along which the paper panel is bent.

[0018] Also, a termite-proof foundation structure disclosed by the present invention includes a paper panel that is continuously provided in such a manner that: extending from an outer surface of a base part of a strip footing, passing through a connection part between the base part and an erected part; extending upward along a side surface of the erected part; bending toward a dirt floor along a lower corner part of a construction joint between the erected part and a dirt floor concrete placed up to an intermediate height of the erected part; and continuously covering a predetermined range of a lower peripheral part of the dirt floor concrete. A termite-proof surface subjected to a termite-proof treatment is formed on the paper panel, within a predetermined range, such that the lower corner part of the construction joint is interposed in the termite-proof surface. Effects of the Invention

[0019] In the termite-proof foundation construction method as described above, an intermediate part of the paper panel is bent and laid along the lower frame member of a steel panel. Furthermore an upper part of the paper panel is erected along an outer surface of the steel panel, and then is folded back in the downward direction so that the upper part of the paper panel is temporarily fixed to the steel panel in a state of being engaged with the lower frame member of the steel panel. In this way, since the paper panel is engaged with the lower frame member of the steel panel so as to be temporarily fixed, it is possible to simplify connection means of a base part formwork and an erected part formwork. As a result, it is possible to considerably reduce components such as presser metal fittings, support members, and connection members that are conventionally required to connect an upper edge part of the base part formwork to the lower frame member of the erected part formwork. It is also possible to further improve the workability by forming folding lines in predetermined positions of the paper panel in advance.

[0020] Also, a termite-proof surface on the paper panel is located at a position along a lower corner part of a construction joint between the dirt floor concrete and the erected part of a strip footing, and is bent along the lower corner part. Thus, it is possible to efficiently form a homogeneous termiteproof line on the construction joint. Since the step of spraying a termite control agent on a construction site can be omitted, it is possible to reduce the construction period and also to stabilize the construction quality in terms of termite-proof performance. Also since no permanent formwork made of synthetic resin is used, it is possible to reduce impact to the soil environment. Brief Description of the Drawings

[0021] [FIG. 1] FIG. 1 is a plan view illustrating an example of a paper panel used for a base part formwork of a strip footing. [FIG. 2] FIG. 2 is a perspective view illustrating an image of the paper panel of FIG. 1, which is attached to a steel panel. [FIGS. 3] FIGS. 3 are cross-sectional views for explaining [Step 2] to [Step 5] of a termite-proof foundation construction method disclosed by the present invention. [FIG. 4] FIG. 4 is a cross-sectional view for explaining [Step 6] of the method. [FIG. 5] FIG. 5 is a cross-sectional view for explaining [Step 7] of the method. [FIG. 6] FIG. 6 is a cross-sectional view for explaining [Step 8] of the method. [FIG. 7] FIG. 7 is a cross-sectional view for explaining [Step 9] of the method. [FIG. 8] FIG. 8 is a cross-sectional view for explaining [Step 10] of the method. [FIG. 9] FIG. 9 is a cross-sectional view for explaining [Step 11] of the method. [FIG. 10] FIG. 10 is a plan view illustrating a variation of the paper panel. [FIG. 11] FIG. 11 is a perspective view illustrating an image of the paper panel of FIG. 10, which is attached to a steel panel. [FIG. 12] FIG. 12 is a perspective view illustrating an image of the paper panel of FIG. 11 in a state in which it is unfolded and erected after the steel panel is removed. [FIG. 13] FIG. 13 is a perspective view illustrating an image of the paper panel of FIG. 12 in a state in which it is bent to be laid on the dirt floor surface. Mode for Carrying Out the Invention

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings and according to the steps recited in the scope of the claims.

[0023] In the termite-proof foundation construction method, a bendable paper panel 1 is used for a base part formwork of a strip footing and a steel panel 3 is used for an erected part formwork. Here, a description is given on the steel panel 3 used for the termite-proof foundation construction method with reference to FIGS. 2 and 3. The steel panel 3 is not particularly different from the conventional steel panels. It is constituted of: a face plate 31 subjected to a surface treatment for improving detachability from the concrete; and frame members (a vertical frame member 32, an upper frame member 33, and a lower frame member 34) attached to the four sides of a back face (outer surface) of the face plate 31. In the example, the vertical frame member 32 is a member having a flat rectangular cross section, and each of the upper frame member 33 and the lower frame member 34 is a member having an unequal L-shaped cross section (see FIGS. 3). The member having the L-shaped cross section is made by connecting: a long piece 35 orthogonally intersecting the face plate 31 and a short piece 36 extending in the inside direction of the surface of the face plate 31.

[0024] Stiffening ribs (longitudinal ribs 37 and lateral ribs 38) are attached to the intermediate part of the back face of the face plate 31. The longitudinal ribs 37 and the lateral ribs 38 in the example are each made of a flat plate material, and they are intersected with each other and arranged in parallel crosses so as to divide the height and the width of the steel panel 3 into a plurality of parts. The respective numbers and placement intervals of the longitudinal ribs 37 and the lateral ribs 38 are appropriately set according to the whole size of the steel panel 3 and the like, while the paper panels 1, described below, are prepared in advance to correspond to the arrangement of the ribs of the steel panel 3.

[0025] Each shallow recessed spaces divided by the frame members 32, 33 and 34, and the ribs 37 and 38 on the back face side of the streel panel 3 has a rectangle shape viewed from the front. In the Specification of the present application, this shallow recessed space is referred to as a “recess between the ribs” (having no reference numeral). Also for the sake of explanation below, an opposing distance between the lower frame member 34 and the lateral rib 38 as well as an opposing distance between the lateral ribs 38 and 38 are each defined as a “height of the recess between the ribs” while an opposing distance between the vertical frame member 32 and the longitudinal rib 37 as well as an opposing distance between the longitudinal ribs 37 and 37 are each defined as a “width of the recess between the ribs”. In the example, all the nine recesses between the ribs are set to have the same height A and the same width B. However, the size of the recess between the ribs may differ according to the position.

[0026] [Step 1] FIG. 1 shows a planar shape of the paper panel 1 prepared corresponding to the steel panel 3. The paper panel 1 is formed by a material such as thick processed paper or thin cardboard, which has an appropriate rigidity for withstanding a filling pressure at the time of placing concrete and a water resistance as well as a water repellency for avoiding softening due to moisture of the concrete.

[0027] The paper panel 1 in the example is a vertically elongated rectangle whose width W equals the width B of the recess between the ribs of the steel panel 3. In the height (vertical side) direction, an upper part 11, an intermediate part 12 and a lower part 13 are integrally continued. The upper part 11 is set to have a height approximately two times larger than the height A of the recess between the ribs of the steel panel 3. More specifically, the height of the upper part 11 is set so as not to be less than the appropriate height such that an upper side edge 14 of the upper part 11 can be engaged with an inside corner between the long piece 35 and the short piece 36 of the lower frame member 34 in Step 4 described later. The intermediate part 12 has a height corresponding to the cross section size (i.e. total size of the long piece 35 and the short piece 36) of the lower frame member 34 of the steel panel 3. The lower part 13 has a height corresponding to the hypotenuse length of the base part having a substantially trapezoidal cross section. In an area from the boundary line between the intermediate part 12 and the lower part 13 to the upper part 11, a plurality of folding lines 21-25 is processed so as to extend in the width direction. The particular positions and functions of the folding lines 21-25 will be described later with reference to FIGS. 3 illustrating the procedures for attaching the paper panel 1 to the steel panel 3.

[0028] On the upper part 11 of the paper panel 1, a termite-proof surface 15 is formed so as to extend in a strip shape in the width direction. The termiteproof surface 15 is formed by an appropriate termite-proof treatment, i.e. application or impregnation of a medical agent to a base paper of the paper panel 1, or attachment, in a stretched manner, of a flexible sheet material with which the medical agent is mixed. However, in the present invention, the specific termite-proof treatment methods and the ingredients of the medical agent are not particularly limited. The termite-proof surface 15 may be formed on either one of the front and back surfaces of the paper panel 1, or may be formed on both surfaces. The specific position and function of the termite-proof surface 15 will be described later with reference to FIG. 7.

[0029] [Step 2] At the time of construction of the strip footing, an appropriate support member 54 is provided on a construction surface so as to support a formwork and a reinforcing bar 53 of the strip footing. To the construction surface, the foundation work such as laying broken stones 51 and laying leveling concrete 52 has been performed. The steel panel 3 is vertically built on the support member 54 so as to form the erected part formwork. As to peripheral components of the formwork such as U pins, separators and fastening fittings for connecting the steel panel 3, although they are not shown in the drawings, it is possible to appropriately combine and use such conventional peripheral components in the present invention.

[0030] [Step 3] Next, as shown in FIGS. 3(a) to 3(b), the intermediate part 12 of the paper panel 1 is stacked on the lower frame member 34 of the steel panel 3 in the state in which the width of the paper panel 1 aligns with the width of the recess between the ribs of the steel panel 3. Then, the folding lines 21, 22 and 23 formed in the intermediate part 12 are bent so that the intermediate part 12 is put in and laid along the inside of the lower frame member 34 of the steel panel 3. That is, in this paper panel 3, the folding line 21 is set to serve as the boundary line between the lower part 13 and the intermediate part 12, and the folding line 23 is set to serve as the boundary line between the intermediate part 12 and the upper part 11. In the example, the folding line 21 located at the lowest position in FIG. 1 is a mountain fold viewed from a worker, and superimposed on the upper end edge of the short piece 36 of the lower frame member 34. The folding line 22 that is the second from the bottom is a valley folded, and pressed against the inside corner between the short piece 36 and the long piece 35 of the lower frame member 34. The folding line 23 that is the third from the bottom is a valley fold, and is pushed into the inside corner between the long piece 35 and the face plate 31 of the lower frame member 34. Thus, by accurately forming the folding lines 21 to 23 according to the cross section size of the lower frame member 34, it is possible to temporarily fix the paper panel 1 to the steel panel 3 by only this pushing of the intermediate part 12 into the lower frame member 34.

[0031] [Step 4] In the example, when the upper part 11 of the paper panel 1 is erected along the outer surface of the steel panel 3, the uppermost folding line 25 is located at a position that abuts a lower edge of the lateral rib 38 directly above the lower frame member 34, as shown in FIG. 3(c).  Then, the upper part 11 of the paper panel 1 is folded back along the folding line 25 in the downward direction, and the folded-back upper side edge 14 is put on the intermediate part 12 that is bent and laid along the shape of the lower frame member 34, so that the folded-back upper side edge 14 is pushed into and engaged with the inside corner between the long piece 35 and the short piece 36 of the lower frame member 34. Thus, the part from the folding line 25 to the upper side edge 14 is tightly stretched diagonally between the lower frame member 34 and the lateral rib 38 so that the intermediate part 12 is pressed against the lower frame member 34. Accordingly, the size of the part from the folding line 25 to the upper side edge 14 of the upper part 11 of the paper panel 1 is set to correspond to the size of the part between the lower frame member 34 and the lateral rib 38. With this engagement, the intermediate part 12 and the upper part 11 of the paper panel 1 are fixed between the lower frame member 34 and the lateral rib 38 that is located directly above the lower frame member 34, of the steel panel 3. Note that the height of the folded-back part of the upper part 11 of the paper panel 1 may be set to be a little larger in advance, so as to position the upper side edge 14 by bending and / or cutting it on site according to the height of the recess between the ribs.

[0032] [Step 5] After the upper part 11 and the intermediate part 12 of the paper panel 1 are fixed to the steel panel 3, the lower part 13 of the paper panel 1 is inclined so as to spread toward the bottom according to the shape of the base part so that an appropriate lower side part of the lower part 13 is fixed to the construction surface, as shown in FIG. 3(d). Thus, the base part formwork is completed.

[0033] [Step 6] Subsequently, as shown in FIG. 4, concrete is placed in a space inside the formwork, which is surrounded by the base part formwork (the lower part 13 of the paper panel 1) and the erected part formwork (the steel panel 3), so as to integrally form a base part 41 and an erected part 43. At this time, the filling pressure of the concrete acts in a direction to push out the lower part 13 of the paper panel 1 from the inside of the base part formwork toward the outside. However, since the intermediate part 12 of the paper panel 1 is fixed to the lower frame member 34 of the steel panel 3 in a folded manner, the state of the lower part 13 is appropriately maintained.

[0034] [Step 7] After a predetermined curing time elapses and the concrete hardens, the upper side edge 14 of the paper panel 1, which is engaged with the lower frame member 34 of the steel panel 3, is pulled out toward the outside so as to release the engagement in [Step 4], as shown in FIG. 5. Then, the intermediate part 12 and the upper part 11 of the paper panel 1 is unfolded toward the outside and separated apart from the steel panel 3 so as to remove only the steel panel 3. At this time, the lower part 13 of the paper panel 1 is adhered to the concrete of the base part 41.  However, even when it is peeling to some extent, it can be laid on the concrete once again.

[0035] [Step 8] After removing the steel panel 3, the intermediate part 12 of the paper panel 1 is once again pushed into and laid on the connection part between the base part 41 and the erected part 43, as shown in FIG. 6. Although the cross section size of the concrete surface after removing the steel panel 3 differs from the cross section size of the lower frame member 34 of the steel panel 3 by the material thickness of the face plate 31 and the lower frame member 34 of the steel panel 3, such a slight difference causes no problem because this part is backfilled in the next step. The upper part 11 of the paper panel 1 is extended upward along the side surface of the erected part 43, and temporarily attached to the surface of the concrete using adhesive tape (not shown) or the like.

[0036] [Step 9] Subsequently, as shown in FIG. 7, backfilling soil 5 is put into the dirt floor space surrounded by the strip footing so as to bury the strip footing up to the intermediate part of the erected part 43 in the height direction. After that, soil compaction and ground leveling are performed so as to prepare a dirt floor surface 51. The intermediate part 12 and the lower part 13 of the paper panel 1 are buried by the backfilling soil 5, while an approximately half part of the upper part 11 is exposed above the dirt floor surface 51. The position of the termite-proof surface 15 formed on the paper panel 1 in advance is set to substantially correspond to the height of the dirt floor surface 51. In other words, the dirt floor surface 51 is prepared so as to correspond to the vicinity of the center of the area of the termite-proof surface 15 formed on the paper panel 1. Also, the folding line 24 is formed in the vicinity of the center of the termite-proof surface 15 in the height direction.

[0037] In the example, the center of the termite-proof surface 15 and the folding line 24 are located at a position lower than the position of the folding line 25 that is to abut the lateral rib 38 of the steel panel 3. Such positional relationship between the folding lines 24 and 25 may be upside down depending on the height of the lateral rib 38 of the steel panel 3 and / or the level of the dirt floor surface 51. Also, the termite-proof surface 15 is not necessarily required to extend upward and downward from the folding line 24 in a manner of respectively having the same width. The termite-proof surface 15 may have a larger area, and may disposed so as to cover the whole area of the paper panel 1.

[0038] [Step 10] Subsequently, as shown in FIG. 8, the upper part 11 of the paper panel 1, which is exposed above the dirt floor surface 51, is bent along the folding line 24 such that the upper part 11 is laid along the dirt floor surface 51. At this time, the termite-proof surface 15 is also bent to have an L-shaped cross section.

[0039] [Step 11] As shown in FIG. 9, dirt floor concrete (leveling concrete) 6 is placed on the dirt floor surface 51. Thus, the paper panel 1 is extended up to the height of the dirt floor surface 51 from the outer surface of the base part 41 along the side surface of the erected part 43 via the connection part of the base part 41 and the erected part 43, and bent toward the dirt floor along a lower corner part of the construction joint between the erected part 43 and the dirt floor concrete 6 so as to be continued to cover a predetermined range of a lower peripheral part of the dirt floor concrete 6. In this way, the termiteproof foundation structure is completed, in which the termite-proof surface is provided on the lower corner part of the construction joint.

[0040] FIGS. 10 to 13 are diagrams illustrating a variation of the paper panel used for the termite-proof foundation construction method. The paper panel 1 shown in FIG. 1 is formed such that its width W matches the width B of the recess between the ribs of the steel panel 3. Therefore, when the upper part 11 of the paper panel 1 is unfolded upward or laterally after removing the steel panel 3, a gap is formed between side edges of the paper panels 1 adjacent to each other, which corresponds to the plate thickness of the longitudinal rib 37 or the vertical frame member 32. In order to fill the gap, a paper panel 10 shown in FIG. 10 has an extended width compared to that of the paper panel 1 in FIG. 1.

[0041] The paper panel 10 in FIG. 10 has a center part having the same width W as the width of the paper panel 1 in FIG. 1, and furthermore has widened parts 16 and 16 that are respectively added to both the left and right sides of the center part. In the example, the width X of the widened part 16 is set to be approximately the same as the depth of the recess between the ribs of the steel panel 3. The vertical positional relationship among the plurality of folding lines 21-25 and the termite-proof surface 15 formed on the paper panel 10 in the width direction is the same as that of the paper panel 1 in FIG. 1.

[0042] In the upper part 11 and the intermediate part 12 of the paper panel 10, vertical folding lines 26 and 26 are respectively formed between the center part and both the widened parts 16 and 16. Also, in both ends of the folding line 21 as the boundary between the intermediate part 12 and the lower part 13, cuts 17 are respectively formed so as to have the same size as the width X of the widened part 16.  When the upper part 11 and the intermediate part 12 are engaged with the steel panel 3, each of the widened parts 16 and 16 outside the folding lines 26 is folded on the center part, or bent along the longitudinal rib 37 or the vertical frame member 32 (when needed, including the lower frame member 34) surrounding the recess between the ribs as shown in FIG. 11. Thus, each bent side edge part (i.e. the widened part 16 or the overlapped part of the widened part 16 with the center part) is pushed inside between the height A and the width B of the recess between the ribs so as to be fixed.

[0043] The lower part 13 of the paper panel 10 protrudes outside the steel panel 3 in a state in which the upper part 11 and the intermediate part 12 are fixed to the recess between the ribs. For this sake, the vertical folding lines 26 are not extended to the lower part 13. The lower part 13 protruding outside the steel panel 3 is overlapped with the lower part 13 of the adjacent paper panel 10. The lower parts 13 overlapped with each other may be tightly attached by tape or the like. By overlapping the lower parts 13 of the adjacent paper panels 10, the strength of the base part formwork is improved.

[0044] After the paper panel 10 is fixed to the steel panel 3 as described above, the base part 41 and the erected part 43 are integrally formed by placing the concrete. As shown in FIG. 12, after removing the steel panel 3, the widened parts 16 of the paper panel 10 are unfolded, so that the widened parts 16 and 16 of the adjacent paper panels 10 are superimposed on each other along the side surface of the erected part 43. Furthermore as shown in FIG. 13, after backfilling the dirt floor, the paper panels 10 are bent in a state in which the widened parts 16 and 16 of the adjacent paper panels 10 are superimposed on each other so as to be laid along the dirt floor surface 51 (FIG. 8). In this way, the termite-proof surfaces 15 of the adjacent paper panels 10 are also bent in the state of overlapping with each other so as to be laid under the dirt floor concrete 6. Thus, the termite-proof line without gap can be formed on the construction joint between the erected part 43 and the dirt floor concrete 6.

[0045] For the purpose of forming the termite-proof line without gap, the abovedescribed width X of the widened part 16 of the paper panel 10 may be appropriately changed. For example, the width X of the left and right widened parts 16 may be set such that the side edges of the adjacent paper panels 10 come into contact with each other when the paper panels 10 are unfolded after removing the steel panel 3. Alternatively, the widened part 16 may be added to either one of the left and right side of the center part such that, when the paper panels 10 adjacent to each other are unfolded, the widened part 16 side of the paper panel 10 is overlapped with the other side (either one of the left and right side) of the adjacent paper panel 10 having no widened part 16. Furthermore in the paper panel 10, the width X of the widened part 16 may differ, in case of necessity, between the lower part 13, and the upper part 11 and the intermediate part 12. Also, the cuts 17 may be formed in appropriate parts other than the folding line 21 serving as the boundary between the intermediate part 12 and the lower part 13, according to the manner of bending.

[0046] In this termite-proof construction method as described above, the intermediate part of the paper panel is bent and laid along the lower frame member of the steel panel. Furthermore the upper part of the paper panel is erected along the outer surface of the steel panel, and then is folded back in the downward direction so that the paper panel is temporarily fixed to the steel panel in a state in which the upper part of the paper panel is engaged with the lower frame member of the steel panel. In this way, since the paper panel is engaged with the lower frame member of the steel panel so as to be temporarily fixed, it is possible to simplify the connection means of the base part formwork and the erected part formwork. As a result, it is possible to considerably reduce the components such as presser metal fittings, support members, and connection members that are conventionally required to connect the upper edge part of the base part formwork to the lower frame member of the erected part formwork. It is possible to further improve the workability by forming the folding lines in predetermined positions of the paper panel in advance.

[0047] Also, the termite-proof surface on the paper panel is located at the position along the lower corner part of the construction joint between the erected part and the dirt floor concrete, and is bent along the lower corner part. Thus, it is possible to efficiently form the homogeneous termite-proof line on the construction joint. Since the step of spraying the termite control agent on the construction site can be omitted, it is possible to reduce the construction period and also to stabilize the construction quality in terms of termite-proof performance. Also since no permanent formwork made of synthetic resin is used, it is possible to reduce impact to the soil environment.

[0048] The technical scope of the invention disclosed in the present application should not be limitedly interpreted by the foregoing embodiments, but should be conceptually interpreted by the scope of the appended claims. The names of the elements in the scope of the appended claims and the description are simply used for the sake of specific comprehensibility of the invention, therefore the concept and properties of the elements should not be excessively limited by these names. As to the members not specifically identified in the scope of the appended claims, all modifications and changes may be appropriately made to the shape, size, structure, material, and number thereof, or the connecting state and relative positional relationship thereof when implementing the invention disclosed in the present application, provided that such modifications and changes are made within the range where the operating principles are substantially equivalent to the foregoing embodiments and where the functions and effects are substantially equal to or greater than the foregoing embodiments.

[0049] Specifically, in the paper panel exemplarily shown, its width is set to correspond to the width B of the recess between the ribs of the steel panel. However, it is possible to use a wide paper panel that covers a plurality of recesses between the ribs and to perform construction work similarly. Also, even when the lower frame member of the steel panel is not a member having the L-shaped cross section as exemplarily shown but a member having a rectangular cross section or the like, it is possible to improve the workability and obtain the similar termite-proof performance by temporarily fix the paper panel to the lower frame member of the steel panel using simplified clips, adhesive tape or the like. Industrial Applicability

[0050] The invention disclosed in the present application can be widely used as a termite-proof construction method for the strip footing or any other similar foundation structures. Also, as to the method for forming a termite-proof line by burying the paper panel 1 subjected to the termite-proof treatment underground, it is applicable to buildings and fixtures not having the concrete foundation. Description of the Reference Numerals

[0051] 1 Paper panel 10 Paper panel 11 Upper part 12 Intermediate part 13 Lower part 14 Upper side edge 15 Termite-proof surface 16 Widened part 21-25 Folding line (in width direction) 26 Folding line (in vertical direction) 3 Steel panel 31 Face plate 32 Vertical frame member 33 Upper frame member 34 Lower frame member 35 Long piece 36 Short piece 37 Longitudinal rib 38 Lateral rib 41 Base part 43 Erected part 5 Backfilling soil 51 Dirt floor surface 6 Dirt floor concrete

Claims

1. A termite-proof foundation construction method for forming a termite-proof line on a construction joint between a strip footing and a dirt floor concrete, using a bendable paper panel for a base part formwork and a steel panel for an erected part formwork, the method comprising the following steps step (1) to step (11):step (1) of subjecting a predetermined position of the paper panel in a height direction to a termite-proof treatment in advance so as to form a termite-proof surface extending on the paper panel in a width direction;step (2) of forming the erected part formwork by vertically building the steel panel on an appropriate support member provided on a construction surface;step (3) of stacking an intermediate part of the paper panel in the height direction on a lower frame member of the vertically built steel panel, and bending and laying the intermediate part along a shape of the lower frame member;step (4) of erecting an upper part of the paper panel along an outer surface of the steel panel and thus folding back the upper part in a downward direction at a position where the upper part abuts a lower surface of a lateral rib provided on the outer surface, and engaging a folded-back upper side edge with the intermediate part bent and laid along the shape of the lower frame member of the steel panel so that the folded-back upper side edge is fixed to the steel panel;step (5) of inclining a lower part of the paper panel so as to spread toward a bottom according to a shape of a base part of the strip footing, and fixing a lower side of the lower part to the construction surface so as to form the base part formwork;step (6) of placing concrete in a space in a formwork surrounded bythe base part formwork and the erected part formwork so as to form the base part and an erected part;step (7) of removing, after curing the concrete, the intermediate part and the upper part of the paper panel from the steel panel by disengaging the engagement, and thus removing the steel panel;step (8) of erecting the upper part of the paper panel along a side surface of the erected part after demolded, and temporarily fixing the upper part to the erected part;step (9) of putting backfilling soil into a dirt floor space surrounded by the strip footing so as to bury the erected part up to an intermediate part thereof in the height direction, and then preparing a dirt floor surface such that the dirt floor surface is located at a region where the termite-proof surface of the paper panel exists;step (10) of bending the upper part of the paper panel, which is exposed above the dirt floor surface, along the dirt floor surface such that the upper part is overlapped with the dirt floor surface; andstep (11) of placing the dirt floor concrete on the dirt floor surface.

2. The termite-proof foundation construction method according to claim 1, wherein step (4) further includes:bending a side edge part of the paper panel erected along the outer surface of the steel panel toward the outer surface of the steel panel such that the side edge part is pushed inside between the lateral rib and the lower frame member and that the upper part of the paper panel is fixed.

3. The termite-proof foundation construction method according to claim 2, whereinthe paper panel is included in a plurality of paper panels having asame configuration, andstep (8) further includes:unfolding the side edge part, which is bent, of each of the plurality of paper panels such that each upper part of the plurality of paper panels adjacent to each other comes into contact or overlaps with each other.

4. The termite-proof foundation construction method according to claim 1, 2 or 3, whereinthe paper panel is included in a plurality of paper panels having a same configuration, andstep (5) further includes:bringing into contact or overlapping, with each other, each lower part of the plurality of paper panels adjacent to each other.

5. The termite-proof foundation construction method according to claim 1, 2 or 3, whereinforming a folding line in the paper panel in advance, in a position along which the paper panel is bent.

6. A termite-proof foundation structure comprising a paper panel being continuously provided in such a manner that: extending from an outer surface of a base part of a strip footing; passing through a connection part between the base part and an erected part; extending upward along a side surface of the erected part; bending toward a dirt floor along a lower corner part of a construction joint between the erected part and a dirt floor concrete placed up to an intermediate height of the erected part; and continuously covering a predetermined range of a lower peripheral part of the dirt floorconcrete, whereina termite-proof surface subjected to a termite-proof treatment is formed on the paper panel, within a predetermined range, such that the lower corner part of the construction joint is interposed in the termite-proof5 surface.

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