JP2022161709A - Precast concrete foundation material for forming mat foundation, forming device for forming precast concrete foundation material, forming method for precast concrete foundation material using forming device, and forming method for mat foundation using precast concrete foundation material - Google Patents

Abstract

To provide novel precast concrete foundation material for forming a mat foundation allowing earthquake-resistant strength to be maintained while being allowed to be safely transported with light weight.SOLUTION: Precast concrete foundation material comprises: bottom walls 4a to 4d in a required shape; and standing walls 6a-1 to 6d-4 standing upward from side edges of the bottom walls 4a to 4d and forming grooves 14a to 14d in the same shape as the required shape in a plan view. Opening windows 20a to 20d in communication with the grooves 14a to 14d are formed in lower ends of the standing walls 6a-1 to 6d-4, and upper surfaces and end surfaces of the grooves 14a to 14d formed with the standing walls 6a-1 to 6d-4 are configured to be open.SELECTED DRAWING: Figure 1

Description

The present invention provides a precast concrete base material for forming a mat foundation, a forming apparatus for forming the precast concrete base material, a method for forming the precast concrete base material using the forming apparatus, and the precast concrete base material. It relates to a method of forming a solid foundation using

For example, as shown in Patent Documents 1 and 2 below, it has been well known to form a raft foundation using a precast concrete foundation material. The raft foundation has an earth floor and a rising part, and both the earth floor and the rising part are made of concrete with reinforcing bars arranged inside. The precast concrete foundation material shown in Patent Documents 1 and 2 is arranged on the outer peripheral edge of the upper surface of pre-formed sacrificial concrete at the construction site, and mainly constitutes the rising portion of the raft foundation. Reinforcing bars are arranged on the discarded concrete, and concrete is placed inside the placed precast concrete base material to embed the reinforcing bars to form the earthen floor of the raft foundation. The precast concrete foundation material as described above is molded at a factory in a state in which the reinforcing bars are included in advance, and is transported from the factory to the construction site with the reinforcing bars protruding to the outside.

JP 2010-70903 A JP 2011-64047 A

Therefore, in the precast concrete foundation material as shown in Patent Documents 1 and 2, the reinforcing bars are transported from the factory to the construction site in a state of protruding to the outside. There is a risk that the reinforcing bars may damage surrounding workers or building materials during transportation. Furthermore, the weight of the base material is heavy and a large crane is required to move the base material, which is not favorable for workability. In addition, in the method of forming a mat foundation using the precast concrete foundation material as shown in the above Patent Documents 1 and 2, before placing the precast concrete foundation material at the construction site, waste concrete is preliminarily spread over a wide area. Since it is necessary to cast concrete, the construction period will be prolonged. In the raft foundation formed using the precast concrete foundation material as shown in Patent Documents 1 and 2, the rising portion is precast concrete formed at a factory, but the dirt floor is poured at the construction site. Since both are made of concrete, the two are not integrally molded, and cracks are likely to occur at the boundary between the two. When such cracks occur, the seismic strength decreases.

The present invention has been made in view of the above-mentioned facts, and its main technical problem is to provide a new precast concrete for raft foundation formation, which is lightweight and can be safely transported and yet maintains sufficient earthquake resistance strength. It is to provide the basic material.

According to the present invention, as a precast concrete base material for achieving the above main technical problems, a precast concrete base material for forming a raft foundation, comprising a bottom wall of a desired shape and a side edge of the bottom wall and an upright wall that forms a groove having the same shape as the required shape in plan view, and an opening window that communicates with the groove is formed at the lower end of the upright wall. A precast concrete base material is provided, characterized in that the upper and end surfaces of the grooves to be formed are open.

Preferably, the desired shape is a straight shape, an L shape, a T shape, or a cross shape. A bottomed hole is preferably formed in the upper surface of the bottom wall. Preferably, the bottom wall is formed with a through hole penetrating vertically, and a female thread is formed on the inner peripheral surface of the bottom wall defining the through hole. In this case, the through hole is preferably formed at the center of gravity of the bottom wall.

A precast concrete foundation constructed in accordance with the present invention comprises a fixed base, an inner mold and an outer mold mounted on the base, the inner mold projecting upward from the upper surface of the base. The outer mold is composed of a plurality of plate-like outer mold pieces connected to the base via hinge means, each of the plurality of outer mold pieces having an inner surface extending from the inner mold. It is rotatable between a molding position close to the outer surface of the mold and a mold release position separated from the outer surface of the inner mold, and when the outer mold piece is positioned at the molding position, it is vertically movable. The upper end position of the outer mold piece is positioned higher than the upper end position of the inner mold piece. It can be molded by a molding device having a bulging portion that is in surface contact with the side surface. In this case, the bulging portion extends from the bulging end surface that comes into surface contact with the outer surface of the inner mold when the outer mold piece is in the molding position, and the outer peripheral edge of the bulging end surface. It has a bulging outer peripheral surface connected to the inner surface of the outer mold piece, and the bulging outer peripheral surface extends in a direction from the inner surface of the outer mold piece toward the outer surface. is preferred. The vertical cross-sectional shape of the inner mold is preferably tapered upward.

A method of producing a precast concrete foundation constructed in accordance with the present invention using the molding apparatus described above includes placing uncured concrete on the inside of the outer mold when all of the outer mold pieces are in the molding position. and forming a precast concrete base material molded body by placing, and after the precast concrete base material molded body has hardened, all the outer mold pieces are removed from the molding position to the release position. and a mold release step of releasing the precast concrete base material compact from the inner mold after the mold release preparation step. In this method, in the mold release preparation step, the through hole and the female thread are formed, a bolt is screwed into the through hole from above, and the top surface of the inner mold is pushed by the tip of the bolt. Better to push Moreover, it is preferable to form the through hole and the female thread in the release preparation step, and to screw the eyebolt into the through hole from above.

As a method of forming a slab foundation using the precast concrete foundation material constructed according to the present invention, a plurality of the precast concrete foundation materials are continuously arranged on the waste concrete as required, and the groove is formed endlessly. a step of arranging a base material for connection, a step of arranging the slab reinforcement by inserting the ends of the slab reinforcement into the opening window after the arranging step of the base material, and a top surface of the groove after the arranging the reinforcement and a foundation placing step of placing uncured concrete from the ground. After the reinforcement arranging step and before the foundation placing step, an anchor bolt arranging step of arranging anchor bolts on the upper end of the precast concrete foundation material is performed, and the anchor bolts are installed on the precast concrete base material. It is preferably supported by supports straddling the upper end of the concrete foundation.

In the precast concrete foundation material constructed according to the present invention, the raised portion of the raft foundation is formed by pouring concrete into the trench at the construction site. In other words, since the rising part of the mat foundation is completed at the construction site, not at the factory where the precast concrete foundation material is molded, the weight of the precast concrete foundation material itself is light. Therefore, according to the precast concrete foundation material constructed according to the present invention, a large-sized crane is not necessarily required to move it, and therefore the workability of the foundation work is improved. Furthermore, since an opening window communicating with the groove is formed at the lower end of the upright wall, the end of the slab reinforcement can be inserted into the opening window after the precast concrete foundation members are arranged as required at the construction site. You can arrange the slab reinforcement with Therefore, there is no need to form the precast concrete base material in a state in which the reinforcing bars are included, and the reinforcing bars do not protrude to the outside during transportation. Therefore, precast concrete foundations constructed according to the invention can be safely transported. Furthermore, according to the method of forming a slab foundation using the precast concrete foundation material constructed according to the present invention, the dump concrete to be poured at the construction site is sufficient only at the place where the precast concrete foundation material is placed. Construction period can be shortened. In addition, in the raft foundation formed using the precast concrete foundation material configured according to the present invention, the earth floor and the rising part are integrally formed without joints, so the earth floor and the rising part are formed seamlessly. Cracks are less likely to occur at the boundary and sufficient seismic strength can be maintained.

1 is a single view of a rectilinear precast concrete foundation, which is one of the preferred embodiments of a precast concrete foundation constructed in accordance with the present invention; FIG. 1 is a single view of an L-shaped precast concrete base material, which is one of the preferred embodiments of a precast concrete base material constructed in accordance with the present invention; FIG. 1 is a single view of a T-shaped precast concrete base material, which is one of the preferred embodiments of a precast concrete base material constructed in accordance with the present invention; FIG. 1 is a single view of a cross-shaped precast concrete base material, which is one of the preferred embodiments of a precast concrete base material constructed in accordance with the present invention; FIG. 1 is a single view of a cross-shaped precast concrete base material, which is one of the preferred embodiments of a precast concrete base material constructed in accordance with the present invention; FIG. 1 shows the construction of a forming apparatus for forming precast concrete foundations constructed in accordance with the present invention; FIG. The figure which shows the method of shape|molding a precast-concrete foundation material using the shaping|molding apparatus shown in FIG. FIG. 5 is a plan view showing an example of a state immediately after completing a foundation material arranging step using various precast concrete foundation materials shown in FIGS. 1 to 4 ; The perspective view which expands and shows a part of FIG. The perspective view which expands and shows a part of state immediately after completing a reinforcing bar arrangement process. The figure which shows typically the basic structure of the state shown in FIG. The figure which shows typically the foundation structure of the state immediately after completing an anchor bolt arrangement|positioning process. The figure which shows typically the foundation structure of the state immediately after completing a foundation placing process.

As will be explained later with reference to the drawings, the precast concrete base material constructed according to the present invention has a bottom wall of a desired shape and upstanding walls rising upward from the side edges of the bottom wall. It can be molded by the device. A more detailed description will now be given with reference to the accompanying drawings showing a preferred embodiment of a precast concrete foundation constructed in accordance with the present invention.

FIG. 1 shows a precast concrete foundation in which the desired shape is linear. The precast concrete base material shown in FIG. 1 is designated as a straight precast concrete base material, and is indicated as a whole by reference numeral 2a to distinguish it from precast concrete base materials having other shapes which will be described later. FIGS. 1(a) to 1(d) respectively show a perspective view, a plan view, a right side view, and a sectional view taken along the line AA of a linear precast concrete base material 2a. The linear precast concrete base material 2a has a linear bottom wall 4a and upright walls 6a-1 and 6a-2 rising upward from both side edges of the bottom wall 4a. Both the upper and lower surfaces of the bottom wall 4a are flat, and four bottomed holes 8a are formed in the upper surface of the bottom wall 4a at intervals in the longitudinal direction. A through hole 10a is formed through the bottom wall 4a in the vertical direction, and a female thread 12a is formed on the inner peripheral surface of the bottom wall 4a defining the through hole 10a. The through hole 10a is formed at the center of gravity of the bottom wall 4a, and the four bottomed holes 8a are formed two on each side of the through hole 10a when viewed in the longitudinal direction. are arranged at equal intervals on the same straight line extending to The standing walls 6a-1 and 6a-2 stand upward from both side edges of the bottom wall 4a extending in the longitudinal direction. A groove 14a extending linearly in the direction is formed. The groove 14a has a linear shape and is the same as the required shape described above. As shown in FIG. 1(c), the outer surfaces 16a of the upright walls 6a-1 and 6a-2 both extend substantially vertically from the upper surface of the bottom wall 4a, but the upright walls 6a-1 and 6a-2 The inner surface 18a extends upward from the upper surface of the bottom wall 4a with a slight outward inclination, and the thickness of the standing walls 6a-1 and 6a-2 increases from the base end toward the extension end. It is being gradually reduced. An opening window 20a communicating with the groove 14a is formed at the base end of the standing wall. As shown in FIGS. 1(b) and 1(c), in the illustrated embodiment, the opening window 20a expands from the inner surface of the standing wall toward the outer surface. The reason for this will be mentioned later. In the linear precast concrete base material 2a having the configuration shown in FIG. 1, the opening window 20a is formed only in the standing wall 6a-1 and not in the standing wall 6a-2. An open window 20a may be formed at the proximal end of the two upstanding walls 6a-1 and 6a-2.

FIG. 2 shows a precast concrete foundation when the required shape is an L shape. The precast concrete base material shown in FIG. 2 is designated as an L-shaped precast concrete base material, and the entirety thereof is denoted by reference numeral 2b. FIGS. 2(a) to 2(d) respectively show a perspective view, a plan view, a right side view, and a cross-sectional view taken along the line AA of the L-shaped precast concrete base material 2b. The L-shaped precast concrete base material 2b has substantially the same configuration as the linear precast concrete base material 2a described above, except that the required shape is L-shaped. is denoted by b, and detailed description thereof will be omitted. The L-shaped precast concrete base material 2b has two upright walls 6b-1 and 6b-2 that are both L-shaped in plan view, and the opening window 20b is located between the two upright walls 6b-1 and 6b-2. It is formed only at one of the lower ends. In the L-shaped precast concrete base material 2b of the form shown in FIG. 2, the opening window 20b is formed in the standing wall 6b-1, but as will be described later, the opening window 20b is formed in the standing wall 6b-2. Sometimes it is.

FIG. 3 shows a precast concrete foundation when the desired shape is a T-shape. The precast concrete base material shown in FIG. 3 is designated as a T-shaped precast concrete base material, and the entirety thereof is denoted by reference numeral 2c. FIGS. 3(a) to 3(d) respectively show a perspective view, a plan view, a front view and a cross-sectional view taken along the line AA of the T-shaped precast concrete base material 2c. The T-shaped precast concrete base material 2c has substantially the same configuration as the linear precast concrete base material 2a described above, except that the required shape is a T shape. is denoted by c, and detailed description thereof is omitted. 3 ( As indicated by the dashed line in b), opening windows 20c are formed only at the lower end portions of the standing walls 6c-2 and 6c-3. In the T-shaped precast concrete base material 2c of the form shown in FIG. 3, the opening window 20c is not formed in the standing wall 6c-1, but as will be described later, the opening window 20c is also formed in the standing wall 6c-1. may have been formed.

FIGS. 4-1 and 4-2 show precast concrete foundations where the required shape is a cross. The precast concrete foundation material shown in FIG. 4 is designated as a cross-shaped precast concrete foundation material, and the entirety thereof is denoted by reference numeral 2d. FIGS. 4-1(a) to 4-2(d) respectively show a perspective view, a plan view, a front view and a sectional view along the line AA of the cross-shaped precast concrete base material 2d. The cross-shaped precast concrete base material 2d has substantially the same configuration as the linear precast concrete base material 2a described above, except that the required shape is a cross shape. d is attached and detailed description thereof is omitted. The cross-shaped precast concrete base material 2d has four erected walls 6d-1 to 6d-4 that are L-shaped in plan view, and as indicated by the dashed line in FIG. 4-1(b), all the erected Opening windows 20d are formed at the lower ends of the walls 6d-1 to 6d-4. One opening window 20d is formed on each side of the standing walls 6d-1 to 6d-4.

FIG. 5 shows the structure of a forming apparatus for forming the linear precast concrete base material 2a shown in FIG. 1 as an example of a forming apparatus for forming a precast concrete base material configured according to the present invention. there is A molding apparatus generally designated 22a has a base 24a fixed on a substantially horizontal surface, and an inner mold 26a and an outer mold 28a mounted on the base 24a. The base 24a extends linearly in the depth direction of the paper surface and has a substantially rectangular cross-sectional shape. A recessed groove 30a extending linearly in the depth direction of the paper is formed on both side edges of the upper surface of the base 24a in the left-right direction of the paper, and the outer surface of the recessed groove 30a viewed in the left-right direction of the paper is open. . The inner mold 26a is fixed to the upper surface of the base 24a by suitable fixing means. The inner die 26a also extends linearly in the depth direction of the paper, protrudes upward from the upper surface of the base 24a, and the upper surface is flatly closed. In the illustrated embodiment, the vertical cross-sectional shape of the inner mold 26a is a hollow trapezoid that tapers upward. The outer mold 28a is composed of two plate-like outer mold pieces 34a connected to the base 24a via hinge means 32a provided in the groove 30a. It extends linearly in the depth direction of the paper surface. As shown in FIG. 5, the two outer mold pieces 34a are arranged one by one on both sides of the inner mold 26a extending linearly in the depth direction of the paper surface. Both of the two outer mold pieces 34a have a molding position (the position indicated by the solid line in FIG. 5) in which the inner surface is close to the outer surface of the inner mold 26a and a release position in which the inner surface is separated from the outer surface of the inner mold 26a. (Position indicated by a two-dot chain line in FIG. 5). When the outer mold piece 34a is positioned at the molding position, the outer mold piece 34a stands substantially perpendicular to the upper surface of the base 24a, and the upper end of the outer mold piece 34a is higher than the upper end of the inner mold 26a. located above. From this, when all the outer mold pieces 34a are positioned at the molding position, inside the outer mold 28a are the inner surface of the outer mold piece 34a, the outer surface of the inner mold 26a, and the upper surface of the base 24a. and a bottom wall forming space 38a defined inside the outer mold 28a and above the inner mold 26a. Due to the presence of the concave groove 30a, the inner surface of the outer mold piece 34a is sufficiently separated from the outer surface of the inner mold 26a at the releasing position. A bulging portion 39 is formed at a required portion of the inner surface of the outer mold piece 34 so as to be in surface contact with the outer surface of the inner mold 26 when in the molding position. The bulging portion 39 has a rectangular bulging end surface 39a that comes into surface contact with the outer surface of the inner mold 26 when the outer mold piece 34 is in the molding position, and extends from the outer peripheral edge of the bulging end surface 39a. It has a bulging outer peripheral surface 39b connected to the inner surface of the mold piece 34, and the bulging outer peripheral surface 39b extends in a direction from the inner surface of the outer mold piece 34 toward the outer surface. Although not shown, the molding device 22a abuts against the end faces of the inner mold 26a and the outer mold piece 34a, and both end faces in the depth direction of the paper surface, thereby defining both end faces in the longitudinal direction of the linear precast concrete base material 2a. There is also an end die fixed or rotatable with respect to the base 24a.

Next, the process of forming the linear precast concrete base material 2a by the forming device 22a will be described with reference to FIG. First, as shown in FIG. 6(a), when all the outer mold pieces 34a are in the molding position, unhardened concrete is placed inside the outer mold 28a to form a linear precast concrete base material. A body 2a' is formed (basic material molded body placing step). Referring also to FIG. 5, the uncured concrete is placed not only in the upright wall forming space 36a but also in the bottom wall forming space 38a. Concrete cast and hardened in the standing wall forming space 36a and the bottom wall forming space 38a later becomes the standing wall 6a and the bottom wall 4a of the linear precast concrete base material 2a, respectively. Therefore, in the concrete cast and hardened in the bottom wall forming space portion 38a, the portion that will later become the bottom wall 4a is referred to as the bottom wall 4a'. As shown in FIG. 6(a), the linear precast concrete base material molding 2a' is molded with the bottom wall 4a' positioned upward. In addition, a bulging portion 39 is formed at a required portion of the inner surface of the outer mold piece 34 and is in surface contact with the outer surface of the inner mold 26 when in the molding position. Concrete does not exist in the portion where the part 39 is formed, and the opening window 20a' of the linear precast concrete base material molding 2a' is formed in this portion. If desired, a well-known mesh made of solid rod-shaped reinforcing bars arranged in a mesh shape is placed in the standing wall forming space 36a and the bottom wall forming space 38a, and then unhardened concrete is poured. good too. In this case, a concrete piece (not shown) that has already hardened is placed on the base 24a in advance, and the mesh bars are arranged on the concrete piece.

Next, after the linear precast concrete base material compact 2a' has hardened, as shown in FIG. 6(b), all the outer mold pieces 34a are swung from the molding position to the releasing position to form the linear precast concrete base material. The molded body 2a' is exposed (mold release preparation step). At this time, the bulging portion 39 formed on the outer mold piece 34 is released from the linear shaped precast concrete base material compact 2a'. In the illustrated embodiment, the bulging outer peripheral surface 39b of the bulging portion 39 formed on the outer mold piece 34 spreads in the direction from the inner surface to the outer surface of the outer mold piece 34. The projection 39 can be released from the standing wall 6' with sufficient ease. In the illustrated embodiment, a through hole 10a' and a female thread 12a' are further formed at required positions of the bottom wall 4a' in the release preparation step (FIG. 6(c)), and the through hole 10a' is threaded from above. An appropriate bolt 40 is rotated clockwise as viewed from above to cause it to spiral (FIG. 6(d)), and the tip of the bolt 40 pushes the upper surface of the inner die 26a. At this time, as shown in FIG. 6(e), the tip of the bolt 40 comes into contact with the upper surface of the inner mold 26a to prevent downward movement of the bolt 40, but the tip of the bolt 40 contacts the inner mold 26a. When the bolt 40 continues to screw while in contact with the upper surface of the bolt 40, the male thread 41 formed on the bolt 40 and the female thread 12a' formed in the through hole 10a' are screwed together to form a straight precast concrete. The base material compact 2a' is moved upward with respect to the inner mold 26a. That is, the straight precast concrete base material compact 2a' is temporarily released from the inner mold 26a.

After the straight precast concrete base material compact 2a' is temporarily released from the inner mold 26a, as shown in FIG. The shaped precast concrete base material molding 2a' is lowered against the inner mold 26a, and the two are brought into contact again. After that, the bolt 40 is further rotated counterclockwise so that the bolt 40 is unscrewed from the through hole 10a'. Next, as shown in FIG. 6(g), an eyebolt 42 is screwed into the through hole 10a' from above, an appropriate wire 44 is wound around the eyebolt 42, and a straight precast concrete base material is formed through the eyebolt 42 by a crane (not shown). The molded body 2a' is lifted upward and released from the inner mold 26a (mold release step). At this time, since the linear precast concrete base material molded body 2a' has already been released once from the inner mold 26a in the mold release preparation process, the linear precast concrete basic material molded body 2a' is removed from the inner mold 26a in the mold release process. It is smoothly released from the mold 26a.

As described above, the forming apparatus 22a for forming the linear precast concrete base material 2a and the method for manufacturing the linear precast concrete base material 2a using the same have been described. ) and the method of manufacturing the precast concrete base material of each shape using the molding apparatus are also configured in the same manner, so detailed description thereof will be omitted. Just to make sure, in the forming apparatus for forming the precast concrete foundation members 2b to 2d of other shapes whose bottom wall has the required shape, the inner mold has the same required shape as the above required shape in plan view. , the plate-like outer mold pieces constituting the outer mold are arranged according to the sides of the required shape.

Next, with reference to FIGS. 7 to 12, the process of forming a raft foundation using various precast concrete foundation materials 2a to 2d shown in FIGS. 1 to 4 will be described. Although illustration is omitted, first, after well-known root-cutting and cracking ground work are performed as required at the construction site, discarded concrete 48 is placed on the outer peripheral edge of the dirt floor 46 . After that, as shown in FIGS. 7 and 8, a plurality of various precast concrete base materials 2a to 2d are continuously arranged on the waste concrete 48, and the grooves 14a to 14d of the precast concrete base materials 2a to 2d are endlessly formed. (substrate arrangement step). FIG. 8 is shown with some parts omitted for easy understanding. A known conditioning mortar 50 may be disposed between the dump concrete 48 and the precast concrete foundations 2a-2d. Also, when moving the precast concrete base materials 2a to 2d, as shown in FIG. , and such eyebolts 42 are preferably hung by a suitable crane. At this time, since the through holes 10a to 10d are formed at the center of gravity of the bottom walls 4a to 4d, the precast concrete base members 2a to 2d can be stably hung in a substantially horizontal state. In the foundation arranging process, the opening windows 20a to 20d formed in the various precast concrete foundation materials 2a to 2d are all arranged on the dirt floor 46 side, and on the opposite side of the dirt floor 46, that is, on the outside of the building in plan view. Not placed. Therefore, in the precast concrete foundation material indicated by reference numeral 2A in FIG. 7, unlike the precast concrete foundation material 2a shown in FIG. is also formed. Further, in the precast concrete base material indicated by reference numeral 2B in FIG. 7, unlike the precast concrete 2b shown in FIG. 2, the opening window 20b is formed in the standing wall 6b-2 instead of the standing wall 6b-1. . Furthermore, in the precast concrete base material indicated by reference numeral 2C in FIG. 7, unlike the precast concrete 2c shown in FIG. 1 is also formed.

After the base material arranging step, as shown in FIGS. 9 and 10, a bar arranging step of arranging solid bar-shaped reinforcing bars is performed. FIG. 9 is partially omitted for easy understanding. In the reinforcement process, the slab reinforcements 52 are arranged by inserting the ends 54 of the slab reinforcements 52 into the opening windows 20a to 20d. As will be appreciated by referring to FIG. 10, the ends 54 of the slab muscles 52 are bent such that the ends 54 are positioned within the grooves 14a-14d. In the reinforcement process, the vertical reinforcements 56 are arranged in the bottomed holes 8a to 8d of the precast concrete base materials 2a to 2d, respectively, and the horizontal reinforcements 58 are fastened to the vertical reinforcements 56 by appropriate fastening means. Also arrange the bars.

After the bar arranging step, an anchor bolt arranging step is carried out for arranging the anchor bolts 60 on the upper ends of the precast concrete base members 2a to 2d. A plurality of anchor bolts 60 are arranged at intervals on the upper ends of the precast concrete foundation members 2a to 2d, and as shown in FIG. be. If desired, the lower ends of anchor bolts 60 may be fastened to longitudinal bars 56 . In FIG. 11, the vertical stripes 56 are omitted for easy understanding. On the other hand, the upper ends of the anchor bolts 60 are supported by supports 64 . The support member 64 is a U-shaped plate material with an open bottom, and straddles the upper end portions of the precast concrete foundation members 2a to 2d. A through hole penetrating vertically is formed in the center of the support 64 , and the support 64 prevents the anchor bolt 60 from collapsing by inserting the anchor bolt 60 through this through hole. The anchor bolts 60 thus arranged extend upward beyond the upper ends of the precast concrete foundation members 2a-2d.

Then, after the anchor bolt installation process (that is, after the reinforcing bar arrangement process), uncured concrete is poured from an arbitrary position on the upper surface of the grooves 14a to 14d formed in the various precast concrete base materials 2a to 2d. to carry out the foundation casting process. Thus, the uncured concrete flows from the grooves 14a to 14d through the opening windows 20a to 20d into the floor 46, and the slab reinforcement 52 is buried. The uncured concrete is poured up to a height position exceeding the upper end positions of the opening windows 20a to 20d in the dirt floor 46, and up to the upper end positions of the grooves 14a to 14d in the precast concrete base materials 2a to 2d. and thus also the vertical and horizontal bars 56 and 58 are embedded. As the placed concrete hardens, the dirt floor 68 and the rising portion 70 of the mat foundation 66 are integrally formed without joints, as shown in FIG. 12 . The supports 64 are removed from the anchor bolts 60 after the poured concrete has set.

In the precast concrete foundation members 2a to 2d constructed according to the present invention, the rising portion 70 of the slab foundation 66 is formed by pouring concrete into the grooves 14a to 14d at the construction site. That is, since the rising portion 70 of the mat foundation 66 is completed at the construction site rather than at the factory where the precast concrete base materials 2a to 2d are formed, the weight of the precast concrete base materials 2a to 2d themselves is light. Therefore, according to the precast concrete foundation members 2a to 2d constructed according to the present invention, a large crane is not necessarily required to move them, and therefore the workability of the foundation work is improved. Furthermore, since opening windows 20a to 20d communicating with the grooves 14a to 14d are formed at the lower ends of the standing walls 6a to 6d, after the precast concrete foundation members 2a to 2d are arranged as required at the construction site, The slab reinforcement 52 can be arranged by inserting the ends 54 of the slab reinforcement 52 into the opening windows 20a to 20d. Therefore, there is no need to form the precast concrete base material in a state in which the reinforcing bars are included, and the reinforcing bars do not protrude to the outside during transportation. Therefore, precast concrete foundations constructed according to the invention can be safely transported. Furthermore, according to the method of forming the slab foundation 66 using the precast concrete base materials 2a to 2d configured according to the present invention, the discarded concrete placed at the construction site is the place where the precast concrete base materials 2a to 2d are placed. The construction period can be shortened because it is sufficient only by Further, in the raft foundation 66 formed using the precast concrete foundation materials 2a to 2d configured according to the present invention, the dirt floor 68 and the rising portion 70 are integrally formed without joints. Cracks are less likely to occur at the boundary between the portion 68 and the rising portion 70, and sufficient seismic strength can be maintained.

2a to 2d: Precast concrete base material 4a to 4d: Bottom plate 6a-1 to 6d-4: Standing wall 14a to 14d: Groove 20a to 20d: Opening window 22a: Molding device 24a: Base 26a: Inner mold 28a: Outside Mold 32a: hinge means 34a: outer mold piece 50: earth floor 52: slab muscle 56: vertical muscle 58: horizontal muscle 60: mat foundation 62: earth floor (of mat foundation) 64: rising part (of mat foundation)

Claims (13)

A precast concrete foundation material for forming a mat foundation, comprising a bottom wall of a desired shape and standing walls rising upward from the side edges of the bottom wall to form a groove having the same shape as the desired shape in a plan view. and an opening window communicating with the groove is formed at the lower end of the upright wall, and the upper surface and the end surface of the groove formed by the upright wall are open. Precast concrete base material. A precast concrete foundation according to claim 1, wherein the desired shape is a straight shape, an L shape, a T shape, or a cross shape. The precast concrete foundation material according to claim 1 or 2, wherein a bottomed hole is formed in the upper surface of the bottom wall. 4. The bottom wall according to any one of claims 1 to 3, wherein a through hole is formed through the bottom wall in a vertical direction, and a female thread is formed on an inner peripheral surface of the bottom wall that defines the through hole. A precast concrete base material according to . 5. The precast concrete base material according to claim 4, wherein the through hole is formed at the center of gravity of the bottom wall. A forming apparatus for forming a precast concrete foundation material according to any one of claims 1 to 5,
A fixed base and an inner mold and an outer mold attached to the base,
The inner mold protrudes upward from the upper surface of the base,
The outer mold is composed of a plurality of plate-like outer mold pieces connected to the base via hinge means, each of the plurality of outer mold pieces having an inner surface extending from the inner mold. and a release position spaced apart from the outer surface of the inner mold, and when the outer mold piece is positioned at the molding position, the The upper end position of the outer mold piece is positioned higher than the upper end position of the inner mold piece. A molding device formed with a bulging portion that is in surface contact with the. The bulging portion has a bulging end surface that is in surface contact with the outer surface of the inner mold when the outer mold piece is in the molding position, and an outer peripheral edge of the bulging end surface that extends from the outer mold piece. 7. The method of claim 6, further comprising a bulging outer peripheral surface connected to the inner surface of the piece, said bulging outer surface extending broadly in a direction from said inner surface toward said outer surface of said outer mold piece. molding equipment. The molding apparatus according to claim 6 or 7, wherein the vertical cross-sectional shape of the inner mold tapers upward. A method for manufacturing the precast concrete foundation material according to any one of claims 1 to 5 using the molding apparatus according to any one of claims 6 to 8,
a base material forming step of placing uncured concrete inside the outer mold to form a precast concrete base material forming when all the outer mold pieces are in the molding position;
a release preparation step of pivoting all of the outer mold pieces from the molding position to the release position after the precast concrete base material compact has hardened;
A method comprising a mold release step of releasing the precast concrete foundation molding from the inner mold after the mold release preparation step. When manufacturing the precast concrete foundation material according to claim 4 or 5 by the method according to claim 9, in the mold release preparation step, the through hole and the female thread are formed, and the through hole A method in which a bolt is threaded from above and the tip of the bolt pushes the upper surface of the inner mold. In the case of manufacturing the precast concrete foundation material according to claim 4 or 5 by the method according to claim 9 or 10, in the mold release preparation step, the through hole and the female thread are formed, and the penetration A method of screwing an eyebolt into a hole from above. A method for forming a raft foundation using the precast concrete foundation material according to any one of claims 1 to 5,
A base material arranging step of continuously arranging a plurality of the precast concrete base materials on the waste concrete as required and connecting the grooves endlessly;
a reinforcement arrangement step of inserting the ends of the slab reinforcement into the opening window after the base material arrangement step to arrange the slab reinforcement;
A method including a foundation placing step of placing uncured concrete from the upper surface of the groove after the reinforcing bar arrangement step. After the reinforcement arranging step and before the foundation placing step, an anchor bolt arranging step of arranging anchor bolts on the upper end of the precast concrete foundation material is performed, and the anchor bolts are installed on the precast concrete base material. 13. The method of claim 12 supported by supports straddling the upper edge of the concrete foundation.

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