JP2014125830A - Split type precast concrete foundation and assembly method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a split type precast concrete foundation which can be carried by one manpower and is easily mounted to a concrete pole, assembled, and installed.SOLUTION: A split type precast concrete foundation is constituted of: a plurality of parts 1, 2 plurally divided in a vertical direction and in a horizontal direction respectively; and a plurality of connection bolts 6 for connecting the plurality of parts 1, 2 divided in the horizontal direction to each other. A pole fixing hole 7 is provided penetrating the plurality of parts 1, 2 vertically divided at a center thereof. A recess 1g and a protrusion 2g mutually fitting are provided at junction surfaces of the parts 1, 2 plurally divided vertically, respectively. A concrete pole 3 is erected in the pole fixing hole 7 and a solidification material such as mortar is poured around the pole 3.

Description

  The present invention is a foundation product made of precast concrete that is installed for the purpose of not falling over even if it receives wind pressure from a typhoon or the like when installing concrete poles for railways, etc. Therefore, it relates to a split-type precast concrete foundation that can be carried by one person and can be easily assembled and installed on a concrete pole.

  Conventionally, concrete poles used for installing traffic lights and electrical equipment along railway lines have small precast concrete roots attached to the ground for the purpose of preventing falls when newly installed. .

  However, in recent years, with the progress of computerization, termination boxes for optical composite cables, which are larger in size than traffic lights and electrical equipment, are often attached to concrete poles. As a result, when installing concrete poles, the area of the attached termination box for optical composite cables, etc. becomes larger, and the wind pressure generated by typhoons and the like increases. It is no longer possible to prevent a fall from being made with a made-up root.

  As a result, when installing a termination box for optical composite cables with a large area on a concrete pole, it is necessary to install a concrete foundation that does not tip over against the wind pressure instead of a foundation foundation. It was.

  However, in the concrete foundation installation work, since it is placed on the site using ready-mixed concrete, construction at a distance from the railway line is a major obstacle to transport and supply of ready-mixed concrete.

  As a result, when installing a termination box for optical composite cables with a large area on a concrete pole, development of a foundation made of precast concrete that can be carried by one person and is easy to assemble and install on a concrete pole is possible. It has been demanded.

Japanese Patent Laid-Open No. 5-239835

  The weight of the precast concrete split foundation for the concrete pole was set to 30 kg or less so that it could be carried and installed by one person.

  The size of this foundation is a horizontal load with a wind pressure of 40m / sec, which is a design wind speed generated by a typhoon, etc., provided that a termination box for an optical composite cable with a size of 0.9 x 1.25m is installed for a concrete pole. As a result of the structural calculation using the allowable resistance bending moment, the prism must have a height of 0.75 m and a width of 0.45 × 0.45 m.

  The weight of the foundation in this dimension is about 350 kg when the unit volume mass of ordinary concrete is calculated as 2.3 kg / l. In order to make the weight of this foundation 30 kg, it was necessary to use the foundation of the split assembly method, and it was necessary to use 12 pieces for the foundation of the prismatic shape.

  In order to transport, install and assemble 12 foundations at the construction site, a great deal of labor and labor is required.

  The present invention has been made to solve the above-described problems. By dividing the foundation into an assembly type, it can be carried by one person and can be easily assembled and installed on a concrete pole. The purpose is to provide a split precast concrete foundation.

  As a result of intensive studies on the above problems, the present inventors have reduced the weight of a precast concrete split-type foundation for a concrete pole from a simple prismatic shape while maintaining an allowable resistance bending moment force. Therefore, it is effective to form a notch with a cross-sectional cutout.

  In addition, the foundation is divided into a plurality of parts to form an assembly type, and the assembly of each part is facilitated by making the upper and lower connecting parts uneven and connecting with connecting bolts in the horizontal direction.

  That is, the present invention relates to a split precast concrete foundation used as a foundation for setting up a pole, a plurality of parts divided into a plurality of parts in the vertical direction and a horizontal direction, and a plurality of parts divided in the horizontal direction. It is composed of a plurality of connecting bolts that connect each other, and a pole fixing hole is provided in the center through a plurality of parts divided in the vertical direction. A plurality of notch portions for providing a resistance force are provided, and a concave portion and a convex portion that are fitted to each other are provided on the coupling surface of each part divided in the vertical direction. is there.

  According to the foundation of the present invention, it can be carried by one person and can be easily assembled and installed on a concrete pole.

  The weight of one divided part of the foundation is preferably 30 kg or less. In addition, the dimensions of the foundation may be determined by taking into account that the height relative to the cut-out cross-sectional area is 30 kg or less. Furthermore, the shape of the foundation can be significantly reduced in weight by increasing the notch area by changing the cross section from a simple prismatic shape to a notch shape.

  Further, when the cutout portion is viewed in a plan view, for example, it is formed in a substantially trapezoidal cross section and / or a substantially triangular cross section (substantially V-shaped cross section), that is, the cutout portion gradually expands in the tip direction. By forming (see Fig. 6), the resistance of the pole to overturning is increased by securing a large number of cross-section notches, so that the pole can easily fall over even under wind pressure due to typhoons. Can be prevented.

  The size of the notch area is determined in consideration of the structural durability of the wind pressure of 40m / sec, which is generated by a typhoon, etc., as a basis against a horizontal load even if an allowable resistance bending moment that does not fall is applied. do it. Note that the shape of the notch is not limited to the shape described above.

  The concrete used in the manufacture of this foundation can be applied to ordinary concrete with a design standard strength of 24 N / mm2 or more, which is generally used.

  The assembly method of this foundation can be easily assembled by connecting with connecting bolts in the horizontal direction, and also provided with holes for fixing with connecting bolts in the notched surface every other step in the horizontal direction. It can be set as the structure which can be firmly connected with a connecting bolt.

  Furthermore, by making the upper and lower connecting portions have a wedge connecting shape of the concave portion and the convex portion, the assembly between the upper and lower parts can be easily performed. As for the structure of the connecting part, the protruding part on the male side of the convex part has a straight edge, and the female side of the concave part is also a fixed groove with a straight edge, making it easy to engage in a wedge shape It can be set as the structure which can be connected and fixed.

  The precast concrete split foundation for concrete poles of the present invention has a horizontal wind pressure of 40 m / sec in design wind speed generated by typhoons when installing termination boxes for optical composite cables with large areas on the concrete pole. It was proved that it would not fall over even if a load was applied.

  Furthermore, in the fall prevention performance demonstration experiment, the simplest method is used as it is, without excavating the ground of the Kanto Loam layer, installing the split foundation on the concrete pole of S2.5m, and using the crushed stone for replacement. Even if it was backfilled with on-site excavated soil (Kanto Loam) and constructed by manual rolling, it did not fall down, and it was proved that it was completely restored after unloading.

  This split-type foundation can be carried by one person and can be easily mounted and assembled on a concrete pole. In addition, since it is made of concrete, it is structurally strong and strong, and has excellent durability.

The horizontal load and bending moment generated by receiving wind pressure (40 m / s is considered here) when a termination box for optical composite cables with a width of 0.9 m and a height of 1.25 m is mounted on a concrete pole are shown. FIG. 1 (a) is a front view and FIG. 1 (b) is a side view. This is a precast concrete skeleton that has been used to prevent the concrete pole from tipping over. Fig. 2 (a) is a plan view, Fig. 2 (b) is a front view, and Fig. 2 (c) is two pieces on the concrete pole. FIG. When a termination box for an optical composite cable with a width of 0.9m and a height of 1.25m was attached to a concrete pole, it was subjected to horizontal load and bending moment generated by receiving wind pressure (40m / s is considered here) Fig. 3 (a) shows the behavior when a precast concrete root rod used in the past is attached to the concrete pole, and Fig. 3 (b) shows the behavior when the foundation is attached to the concrete pole. FIG. FIG. 4 (a) is a conceptual diagram of a cast-in-place concrete foundation installed on a concrete pole, and FIG. 4 (b) is a conceptual diagram of a split precast concrete foundation of the present invention installed on a concrete pole. It is a conceptual diagram which shows the block of one part of the split-type precast concrete foundation which concerns on this invention. FIG. 6 (a) is a plan view and FIG. 6 (b) is a front view showing details of a split precast concrete foundation according to the present invention. It is explanatory drawing which shows the outline | summary of the experimental method of the fall prevention performance verification experiment of the split-type precast concrete foundation which concerns on this invention. It is a conceptual diagram which shows the outline | summary of the experimental method of the fall prevention performance demonstration experiment of the root anchor made from precast concrete conventionally used. It is a conceptual diagram which shows the method to measure the horizontal movement distance and inclination angle in the state which mounted the horizontal load in the fall prevention performance verification experiment. As an example and a comparative example, it is a graph which shows the experimental result of the fall prevention performance demonstration experiment of the split type precast concrete foundation concerning the present invention, and the traditionally used precast concrete root anchor, state inclined by horizontal load It shows the horizontal movement distance at. As an example and a comparative example, it is a graph which shows the experimental result of the fall prevention performance demonstration experiment of the split type precast concrete foundation concerning the present invention, and the traditionally used precast concrete root anchor, state inclined by horizontal load The inclination angle at is shown.

  Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

A. Materials for use of split foundations Precast concrete split foundations for concrete poles according to the present invention are cement, ordinary fine aggregate, ordinary coarse aggregate and water reducing agent or high performance water reducing agent, defoaming added as necessary It consists of an agent etc., and is the same as the precast concrete product generally manufactured.

[Constituent materials]
(1) Cement The cement used in the present invention may be a portland cement such as ordinary Portland cement or early-strength Portland cement, and a mixed cement such as blast furnace cement, and is not limited to the type of cement.

(2) Fine aggregate The fine aggregate used in the present invention may be conventionally used in concrete, and is natural sand such as river sand and land sand, crushed sand, quartz sand, and the like. The fine aggregate ratio of the fine aggregate is preferably 40 to 55%. By setting the fine aggregate ratio within the above range, it is possible to solve the aesthetic problem of the concrete surface such as surface air bubbles (avatar) and uneven color without reducing the basic performance of the concrete such as fluidity and strength.

(3) Coarse aggregate The coarse aggregate used in the present invention may be one conventionally used in concrete, and is natural gravel such as river gravel, crushed stone, and the like.

(4) Water-reducing agent or high-performance water reducing agent In the present invention, a water-reducing agent or high-performance water-reducing agent is used as in the case of conventional concrete. Although the kind of high performance water reducing agent is not specifically limited, A polycarboxylic acid type is preferable. The addition amount is about 0.5 to 1.2% with respect to the cement.

(5) Antifoaming agent In this invention, an antifoaming agent is added as needed. All of the concretes of the present invention can exhibit high fluidity and excellent strength, but depending on the formulation, the amount of entrained air may increase or fine bubbles may be generated on the concrete surface. When an antifoaming agent is used in such a case, concrete having a smooth surface can be obtained. The type of antifoaming agent is not particularly limited as long as it is conventionally used for concrete.

(6) Kneaded water In the present invention, the unit water amount of the kneaded water is preferably 185 kg / m ³ or less, and the water / cement ratio is preferably 55% or less. When the unit water amount exceeds 185 kg / m ³ , it becomes easy to generate breathing water and it becomes difficult to ensure the required strength. Further, if the water / cement ratio is out of the above range, it is difficult to ensure the design standard strength. A more preferable unit water amount is 160 to 180 kg / m ³ .

B. Basic Stability of Concrete Pole with Optical Composite Cable End Box FIGS. 1, 2 and 3 are conventionally used for the horizontal load and bending moment generated when the concrete pole 3 is subjected to wind pressure. In Nekko 5, it indicates that it falls, but the concrete foundation does not fall.

  Fig. 1 shows the horizontal load generated by receiving wind pressure (40 m / s is taken into consideration here) when a termination box 4 for an optical composite cable with a width of 0.9 m and a height of 1.25 m is attached to a concrete pole 3. It is the conceptual diagram which showed the bending moment.

  Table 1 shows the horizontal load generated by receiving wind pressure (40 m / s is considered here) when a termination box 4 for an optical composite cable with a width of 0.9 m and a height of 1.25 m is attached to a concrete pole. It is the table | surface which calculated the bending moment. As a result of the calculation, the horizontal force is H = 0.139 tonf, and the bending moment is M = 0.351 tonf · m.

  FIG. 2 shows a precast concrete root rod 5 conventionally used to prevent the concrete pole 3 from falling. 2 (a) and 2 (b) show the shape of the root rod 5, and FIG. 2 (c) is a conceptual diagram in which two root rods 5 are attached to the concrete pole 3 with connecting bolts 6. FIG.

  Fig. 3 shows the horizontal load generated by receiving wind pressure (40 m / s is considered here) when the termination box 4 for optical composite cable with a width of 0.9 m and a height of 1.25 m is attached to the concrete pole 3. It is a conceptual diagram at the time of receiving bending moment.

  Fig. 3 (a) is a conceptual diagram showing that the precast concrete girder 5 used in the past has a smaller allowable resistance bending moment with respect to the bending moment generated from the wind pressure, and as a result, falls. It is. FIG. 3 (b) is a conceptual diagram showing that the allowable resistance bending moment is larger than the bending moment generated from the wind pressure in the concrete foundation, and as a result, the concrete foundation does not fall.

  Table 2 shows the horizontal force and bending generated by receiving wind pressure (40 m / s is taken into consideration here) when a termination box for optical composite cables with a width of 0.9 m and a height of 1.25 m is mounted on a concrete pole. It is the table which carried out stability calculation about the case where a concrete foundation with a penetration depth of 0.75m and a penetration width of 0.45m was installed for the moment.

  As a result, if a concrete foundation with a penetration depth of 0.75 m and a penetration width of 0.45 m is installed, it will not fall over even if it receives bending moment due to horizontal force due to wind speed (40 m / s is considered here). It could be confirmed.

C. Shape and structure of split foundation The shape and structure of a precast concrete split foundation for the concrete pole of the present invention are shown in FIGS. 4, 5, and 6. In this figure, the split-type precast concrete foundation A according to the present invention shows three-stage stacking, and the number and dimensions of the stack are arbitrary depending on conditions such as various concrete poles 3 and termination boxes 4 for optical composite cables to be attached. Can be changed.

  FIG. 4 is a conceptual diagram comparing the split-type precast concrete foundation A according to the present invention and an in-situ concrete foundation. Fig. 4 (a) shows the case where the cast-in-place concrete foundation is installed, and Fig. 4 (b) shows the case where the precast concrete split-type foundation A for the concrete pole of the present invention is installed. ) Is generally as illustrated (see FIGS. 6A, 6B, etc.). However, it is needless to say that the size is not limited to this.

  FIG. 5 is a block of one part of the split precast concrete foundation A according to the present invention. The weight of the blocks 1 and 2 of this part is 30kg or less, and it can be carried by one person and is easy to install and assemble on the concrete pole 3.

  FIG. 6 shows an example of the details of the split-type precast concrete foundation A according to the present invention, which has a large number of cross-sectional notch surfaces and a large cross-sectional area to reduce weight and resistance to falling of the concrete pole 3. Increased power has been achieved.

  In FIG. 6, by providing a cutout portion B having a substantially trapezoidal cross section and a cutout portion C having a substantially triangular cross section (substantially V-shaped cross section) when viewed in plan on the outer surface of each part 1, 2, Wide cross-sectional cutout surfaces 1a to 1g and cross-sectional cutout surfaces 2a to 2g are formed, respectively.

  Further, by providing a notch portion B having a substantially trapezoidal cross section and a notch portion C having a substantially triangular cross section (substantially V-shaped cross section), a plurality of ribs D projecting in four directions are formed on the side of the foundation A. The rib D also provides a great resistance against the falling of the concrete pole 3.

  This foundation A is designed to assemble six parts 1 and 2 in a three-stage stack, and connect and fix the parts 1 and 2 in the horizontal direction of each stage with connecting bolts 6 respectively.

  In addition, the connecting part between the upper and lower parts 1, 1 and 2, 2 is a wedge connecting shape of the concave part 1g and the convex part 2g, so that it is easy to assemble, and the connecting bolt 6 is provided on the notched surface every other step. The bolt connection hole 1a and the bolt insert 2a to be fixed are provided in the horizontal direction so that the connection bolt 6 can be firmly connected. The bolt connecting hole 1a is provided on the notch surface on the part 1 side, and the bolt insert 2a is provided on the notch surface on the part 2 side.

  Further, a concrete pole fixing hole 7 is provided in the center portion of the foundation A so as to penetrate the parts 1 and 2 of each step in the vertical direction. And the concrete pole 3 is stood in this foundation A by standing up in the said concrete pole fixing hole 7, and filling solidification materials, such as mortar, in the circumference | surroundings.

  Table 3 shows a comparison between a cast-in-place concrete foundation and a split precast concrete foundation. The cast-in-place concrete foundation is made of ready-mixed concrete with a formwork, and the total weight is 350kg. In addition, formwork, concrete placement work, compaction work and curing work are required, and operation cannot be started until the concrete reaches a predetermined strength.

  On the other hand, the split-type precast concrete foundation is a precast concrete product, so that it is not necessary to place concrete and can be constructed by transportation and assembly to the site, which can contribute to labor saving and cost reduction. In addition, the service can be started on the same day after construction. In addition, the total weight has been reduced to 162kg, which is less than 1/2 of the cast-in-place concrete foundation.

[Example]
An embodiment of the present invention will be described with reference to the drawings. FIG. 7 shows, as an embodiment, an outline of an experimental method of a fall prevention performance demonstration experiment of the split precast concrete foundation A according to the present invention. The split-type precast concrete foundation A was the Kanto loam layer under the 10cm road crushed stone, so it was excavated into an S2.5m concrete pole 3 and parts blocks 1 and 2 with a weight of 30kg or less. After several pieces were easily carried, assembled and installed by one person, instead of using crushed stones for replacement, as a simplest method, they were backfilled with on-site excavated soil (Kanto Loam) and pressed manually. This is a performance check in the case of construction on the most dangerous side against overturning without using a rolling machine.

  The horizontal load is the same as the horizontal load and bending moment generated by receiving wind pressure (40 m / s is taken into consideration here), and made of steel with pulley attached to a concrete mount (about 650 kg) as the foundation for reaction force. It was made to act by loading concrete weight using a frame and a wire. When the horizontal load at the load point is calculated from the bending moment, the horizontal load is as follows.

    Horizontal load at the load point = (total bending moment 0.1316 + 0.0035 = 0.1351 tonf · m) ÷ (height of the load point 1.55 m) = 0.0872ton = 87.2kg

  In the experiment of the fall prevention performance demonstration experiment of the split precast concrete foundation A in the example, a horizontal load of 0.0872 tonf (87.2 kg) is applied to the concrete pole 3 of S2.5m as shown in FIG. Was measured. The amount of displacement was measured by moving the horizontal movement distance by attaching a swing to the top of the pole for each loaded load.

  FIG. 9 shows a method of measuring the horizontal movement distance and the inclination angle in a state where a horizontal load is loaded in the overturn prevention performance demonstration experiment.

  Table 4 shows the experimental results of the fall prevention performance demonstration experiment. As an example, the experimental results of the fall prevention performance demonstration experiment of the split precast concrete foundation according to the present invention are shown.

  FIG. 10 shows an experimental result of the fall prevention performance demonstration experiment of the split-type precast concrete foundation A according to the present invention as an example, and shows a horizontal movement distance in a state of being inclined by a horizontal load.

  FIG. 11 shows, as an example, experimental results of a fall prevention performance demonstration experiment of the split-type precast concrete foundation A according to the present invention, and shows an inclination angle in a state inclined by a horizontal load.

  The split precast concrete foundation A according to the present invention, as a result of the overturn prevention performance demonstration experiment, has a horizontal movement distance of 6 mm and a maximum rotation angle of 0.23 ° at a horizontal load wind pressure (wind speed of 40 m / s), and hardly tilts. It was. Further, even when a horizontal load with a safety factor of 1.87 times the horizontal load was applied, the horizontal movement distance was 27 mm and the rotation angle was 1.00 °. Moreover, even after unloading, the horizontal movement distance was 7mm, and the rotation angle was 0.26 °.

[Consideration of results]
The split-type precast concrete foundation according to the present invention can be easily carried, mounted, assembled and installed on a concrete pole of S2.5m by one person, even when it is backfilled with on-site excavated soil (Kanto loam) , Even if a horizontal load with a safety factor of 1.87 is applied to the horizontal load generated by receiving wind pressure (40 m / s is considered here), it is almost inclineable even after unloading. It was possible to recover and prove that there was no risk of falling.

[Comparative example]
FIG. 8 shows, as a comparative example, an outline of an experimental method for a fall prevention performance demonstration experiment of a precast concrete root fence 5 that has been conventionally used. The experiment was performed with the same experimental method and experimental conditions as in the examples.

  Table 4 shows the experimental results of the fall prevention performance demonstration experiment. As a comparative example, the experimental results of the fall prevention performance demonstration experiment of the precast concrete root-knots that have been conventionally used are shown.

  FIG. 10 shows an experimental result of the fall prevention performance verification test of a precast concrete root anchor used conventionally as an example, and shows a horizontal movement distance in a state inclined by a horizontal load.

  FIG. 11 is an experimental result of the fall prevention performance verification experiment of a precast concrete root anchor used conventionally as an example, and shows an inclination angle in a state inclined by a horizontal load.

  As a result of the demonstration test of the anti-falling performance, the precast concrete roots used in the past are affected by a horizontal movement distance of 100 mm and a maximum rotation angle of 3.70 ° under horizontal load wind pressure (wind speed 40 m / s). Inclined. On the other hand, the horizontal movement distance at a safety factor of 1.87 times the horizontal load was 245 mm and the rotation angle was further inclined to 9.10 °, and even after unloading, the horizontal distance was 180 mm and the angle was 6.68 °.

[Consideration of results]
Conventionally used precast concrete roots are generated by receiving wind pressure (40 m / s is considered here) when backfilling with excavated soil (Kanto loam) and performing manual rolling. It did not recover because it was greatly inclined with respect to the horizontal load, and remained largely inclined even after unloading.

  This table shows the horizontal force and bending generated by receiving wind pressure (40 m / s is taken into consideration here) when a termination box for optical composite cables with a width of 0.9 m and a height of 1.25 m is attached to a concrete pole. It is the table which calculated the moment.

  This table shows the horizontal force and bending generated by receiving wind pressure (40 m / s is taken into consideration here) when a termination box for optical composite cables with a width of 0.9 m and a height of 1.25 m is attached to a concrete pole. It is the table which carried out the stability calculation about the case where the concrete foundation whose penetration length is 0.75m and the penetration width is 0.45m is installed for Momen.

  This table shows a comparison between on-site concrete foundation and split precast concrete foundation.

  This table shows the experimental results of the fall prevention performance demonstration experiment. As an example, the experimental results of the fall prevention performance demonstration experiment of the split-type precast concrete foundation according to the present invention and the traditionally used precast concrete rootstock. Is shown.

  In the present invention, when installing a concrete pole for a railway by supporting it on a foundation, it can be carried by one person by dividing the foundation into an assembly type, and it can be easily assembled and installed on the concrete pole. It can be carried out.

1 Bolt insertion side 1a of a connecting bolt of one part block of a split-type foundation Bolt connecting hole 1b Cross-sectional cutout surface 1c for weight reduction Cross-section cutout surface 1d for weight reduction Cross-section cutout surface 1e for weight reduction Cross-sectional cut-out surface 1f for weight reduction Cross-sectional cut-out surface 1g for weight reduction Recesses for connecting the blocks in the vertical direction Recesses with straight edges at the female side 2 Nut side 2a Bolt insert 2b Section cut-out surface 2c for weight reduction Section cut-out surface 2d for weight reduction Section cut-out surface 2e for weight reduction Section cut-out surface 2f for weight reduction Section cut-out surface for weight reduction 2g Convex part for vertical connection of block Convex part with straight edge on male side 3 Concrete pole 4 Termination box for optical composite cable 5 Root anchor 6 Connection bolt 7 Concrete pole fixing hole A Foundation (Division Expression (Recast concrete foundation)
B Flat trapezoidal cutout C Flat triangular cutout D Rib

Claims (5)

  In a split precast concrete foundation used as a foundation for setting up a pole, a plurality of parts divided into a plurality of parts in the vertical direction and a horizontal direction and a plurality of parts divided in the horizontal direction are connected to each other. It is composed of a connecting bolt, and a pole fixing hole is provided in the center through a plurality of parts divided in the vertical direction. It is a cut-off that provides weight reduction and resistance to overturning of the pole on the outer surface of each part. A split precast concrete foundation, wherein a plurality of notches are provided, and a concave portion and a convex portion that are fitted to each other are provided on a joint surface of each part that is divided into a plurality of parts in the vertical direction.   The split precast concrete foundation according to claim 1, wherein the notch is formed in a substantially trapezoidal cross section and / or a substantially triangular cross section when viewed in plan.   The split-type precast concrete foundation according to claim 1 or 2, wherein the weight of each part is 30 kg or less.   The split-type precast concrete foundation according to any one of claims 1 to 3, wherein a linear edge is provided in each of the concave portion and the convex portion.   It consists of multiple parts divided into multiple parts in the vertical and horizontal directions, with a pole fixing hole penetrating through the parts divided in the vertical direction in the center, and lightweight on the outer surface of each part In the method of assembling a split-type precast concrete foundation that is provided with a plurality of notches that provide resistance to turning of the pole and the pole, each part adjacent in the horizontal direction is connected to each other through the part in the horizontal direction A method of assembling a divided precast concrete foundation, wherein the parts connected by bolts and adjacent parts in the vertical direction are connected by fitting recesses and projections provided on the connecting surface between the parts together.