JPH04368566A - Foundational construction and form for pile foundation - Google Patents

Abstract

PURPOSE:To construct a pile foundation footing and an underground beam for a building structure or the like in an efficient manner. CONSTITUTION:A circular form 2 is set up so as to make a pile head part come to a central position and fixed and held on leveling concrete. In addition, each edge 2a of the circular form 2 is fixed to side ends of two adjacent forms 1 and 1 with nails 3 for connection, and a foundational concrete form is solidly assembled and foundation concrete is placed in these forms 1 and 2.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a foundation construction method and formwork for pile foundations, and in particular to a foundation construction method for constructing underground beams to connect circular pile foundation concrete for building structures, etc., and circular pile foundations. Concerning formwork for pile foundations for pouring foundation concrete.

0002

2. Description of the Related Art Generally, pile foundation structures are often adopted for the foundations of large-scale building structures, taking into consideration the surrounding ground conditions and the shape and weight of the building. Appropriate pile types, pile dimensions, and placement are then determined based on each design and construction condition. In addition, the load of the superstructure is distributed and transmitted to each pile via footings, etc., but at this time, the underground beam structure that connects the pile heads is the main structural material, and waste concrete is poured between the underground beams. A slab structure is often used. This underground beam structure has the advantage of reducing the weight of the building. By the way, when constructing an underground beam by connecting pile heads in this way, it is necessary to determine its dimensional structure in consideration of the external force acting on the pile heads. At this time, the force acting on the pile cap varies depending on the fixing conditions of the pile cap, but in a fixed structure, generally, the vertical support force V, the pile cap bending moment M, and the horizontal shearing force H act on the foundation footing through underground beams. The structure and dimensions of the pile foundation footing are determined based on the acting force. FIG. 5 is a perspective view showing an example of a foundation structure in which this type of pile foundation and each pile foundation are connected by underground beams. Although only a portion is shown in the figure, a pile foundation footing 20 in the shape of a rectangular parallelepiped with a substantially square planar shape is constructed so as to match the arrangement spacing of the piles 21. Furthermore, an underground beam G having a higher beam height than the pile foundation footing 20 is connected to the pile foundation footing 20 so as to be integrated with the pile foundation footing 20. At this time, the beam height of the underground beam G is determined by the weight of the superstructure, etc., and is often larger than the footing height. Figure 6 shows pile foundation footing 2.
This figure shows the formwork 23 assembled to integrally cast the G part 0 and the underground beam G part. These formworks 23 are
Weir plates 24, 24, which form concrete pouring surfaces and receive concrete lateral pressure, and thick timbers 25, 25, which hold and fix the weir plates 24 to prevent the shape of the formwork from deforming.
It is composed of... The weir plate 24 is generally made of plywood called a control panel or a steel formwork called a metal form, and the end pieces 25 are made of square steel pipes or wood.
Each end piece 25 is fixed to the weir plate 24 at a predetermined position by form ties 26, 26, . . . . Also,
The opposing weir plates 24 are fixedly held by separators 27 to ensure a predetermined finished structure dimension.

0003

[Problem to be Solved by the Invention] However, the formwork for the pile foundation footing described above has a complicated shape, and regular length materials such as metal foam cannot be used, so the control panels are processed to match the dimensions of the pile foundation footing. Each type of formwork must be manufactured, and in the case of a foundation where a large number of piles are driven, it is complicated to construct the underground beam and the pile foundation in one piece. In addition, since the weir plate forms a straight line as shown in Figure 7, the concrete side pressure acts on the weir plate as a uniformly distributed load, and the maximum bending moment occurs at approximately the center of the weir plate, causing the weir in that area to The deflection of the plate is maximum. If the reinforcement with timbers is insufficient, the pressure of the unhardened concrete will cause the weir plates to bulge outward, and there is a risk that the formwork will collapse. In addition, the square footing with the combination of flat plate formwork required more concrete and rebar than the design strength required.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention arranges an arc-shaped formwork so that the pile head is at the center position and fixes it on the concrete, and This method is characterized in that the edge of the formwork is connected to the side end of an adjacent formwork to assemble a formwork for foundation concrete, and the foundation concrete is poured into the formwork.

[0005] Furthermore, as the formwork for the pile foundation used in the above-mentioned foundation construction, a thin plate material is bent at a predetermined bending radius to form an arc shape, and a strip-like rib for connection is formed at the edge. It is something.

[0006]

[Operation] According to the present invention, the arcuate formwork is arranged so that the pile head is at the center position and is fixedly held on the concrete, and the edge of the arcuate formwork is connected to the adjacent formwork. The formwork for the foundation concrete is assembled by connecting it to the side end, and the foundation concrete is poured into the formwork, so the formwork for the pile foundation part can be easily assembled.
The applied concrete lateral pressure is converted into a tensile force in the circumferential direction of the formwork, preventing local protrusion of the formwork and creating the arc-shaped footing expected by the design.

[0007] Furthermore, as the formwork for the pile foundation used in the above-mentioned foundation construction, a thin plate material is bent into an arc shape with a predetermined bending radius, and strip-like ribs for connection are formed at the edges, resulting in a simple structure. Not only can the formwork be made strong, but it can also be easily and reliably connected to adjacent formworks.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the foundation construction method according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 indicates a formwork for an underground beam G, and this formwork 1 is arranged in the longitudinal direction according to the marking marks on the surface of the sacrificial concrete placed in advance.
They are arranged at predetermined intervals near the pile head (not shown). Further, pile foundation forms 2, 2 made of thin steel plates are attached to the ends of each form 1 of the underground beam G in a curved arc shape. In this embodiment, the formwork 2 has a thickness of 0.
It is made of 8mm colored rust-proof steel plate and is curved to form part of a circular arc with a diameter of 1.2m, with a width of 10mm at the end.
A connecting rib 2a of cm is integrally formed so as to be folded back. This rib 2a is applied to the end of the formwork 1 of the underground beam section, and further fixed to the end of the underground beam formwork 1 from the inside with nails 3, 3... to form an integral formwork for foundation concrete. Assemble. Incidentally, a pile 5 is arranged approximately at the center of the pile foundation footing 4 as shown in FIG. 2, and the pile head treatment of the pile 5 is performed based on design specifications. In addition, reinforcing reinforcing bars (not shown) are arranged at the joints between the reinforcing bars treated with the pile caps and the reinforcing bars of the underground beams, so that the acting force from the underground beams G can be reliably transmitted to the pile caps.

[0010]Although thick timbers (not shown) are placed at predetermined intervals to hold and fix the sheathing plates of the underground beam formwork 1, no thick timbers are placed in the circular formwork portion of the footing. Not yet. Here, concrete is supplied into the formwork from a concrete supply device (not shown) such as a concrete pump, and concrete is sequentially poured according to a predetermined procedure. At this time, formwork 1
, 2, the lateral pressure of the unhardened concrete acts uniformly in the circumferential direction as shown in FIG. Therefore, this concrete lateral pressure is converted into a tensile force in the circumferential direction without generating a bending moment on the weir. This circumferential tensile force is very small compared to the allowable tensile strength of the steel plate, and almost no radial deformation of the formwork 2 occurs. Therefore, it can be seen that this circular formwork 2 portion does not require any reinforcement material.

FIG. 3 shows an underground beam G using the above-mentioned circular formwork.
This figure shows an example in which the pile foundation footing 4 and the pile foundation footing 4 are integrally constructed. Note that the upper beam of the circular formwork 2 is constructed by connecting formworks for other beams and performing a predetermined joining process.

The circular formwork 2 described above is formed by connecting formworks formed in an arc shape in advance, and has ribs 2a at the ends.
The bent flat plate-like weir plate may be bent into a predetermined shape when setting the formwork, and the shape of the formwork may be made circular by concrete side pressure. In such cases, resin weir plates may be used. In either case, it can be easily diverted to other pile foundation parts.

FIG. 4 shows an assembly example of a formwork in which an arc-shaped formwork is combined with a flat formwork as a modification of the above-described embodiment. Figure (a) shows an example for constructing a cylindrical independent foundation footing, and figure (b) shows an example of constructing an oval-shaped footing for a plurality of piles. In this case, it is preferable to arrange a predetermined reinforcing end piece in the linear formwork portion. The figure (c) shows an example in which an arcuate formwork is applied to the corner portion of a rectangular footing, and this arcuate formwork makes it possible to simplify the closing of the ends of the formwork.

[0014]

As is clear from the above description, according to the present invention, a plurality of arcuate formworks are fixedly held so that the pile head is at the center position, and the edges of the arcuate formworks are The formwork for the foundation concrete is assembled by connecting it to the side ends of the adjacent formwork, and the foundation concrete is poured into the formwork. This makes it possible to easily assemble the formwork for the pile foundation part, and improves efficiency. Concrete can be placed easily, and as a formwork for the pile foundation used in the above-mentioned foundation construction, thin plate material is bent into an arc shape with a predetermined bending radius, and strip-like ribs for connection are formed at the edges. Therefore, it is possible to use a formwork with an inexpensive and simple structure, and it is also possible to construct an arcuate footing as expected by the design.

[Brief explanation of drawings]

FIG. 1 is an assembly conceptual diagram showing an embodiment of the foundation construction method according to the present invention.

FIG. 2 is an explanatory diagram of concrete lateral pressure distribution during foundation construction according to the present invention.

FIG. 3 is a perspective view showing a part of an underground beam constructed using the formwork of the present invention.

FIG. 4 is a plan view showing a modified example of the arc-shaped formwork according to the present invention.

FIG. 5 is a perspective view showing a part of an underground beam constructed using conventional formwork.

FIG. 6 is a schematic plan view showing an example of a conventional formwork.

FIG. 7 is an explanatory diagram of concrete lateral pressure distribution during foundation construction using conventional formwork.

[Explanation of symbols]

1 Underground beam formwork 2 Formwork for pile foundation 4 Pile foundation footig 5　Pile

Claims (2)

[Claims] Claim 1: An arc-shaped formwork is arranged so that the pile head is in the center position and fixedly held on the concrete, and the edge of the arc-shaped formwork is attached to the side end of the adjacent formwork. A foundation construction method characterized by assembling connected formwork for foundation concrete, and pouring foundation concrete into the formwork. 2. A formwork for a pile foundation, characterized in that a thin plate material is curved at a predetermined bending radius to form an arc shape, and a strip-shaped rib for connection is formed at the edge.