JP2004232328A - Structure of semi-precast arch culvert and its construction method - Google Patents

Abstract

An object of the present invention is to provide a structure of an arch culvert which does not require support, formwork, installation of reinforcing bars, and concrete placement when constructing an arch portion of the arch culvert, and a method of constructing the arch culvert.
After a bottom plate (21) and a side wall (22) of a lower half of an arch culvert are constructed, an upper half arch part of a precast concrete (1) is erected at a connection part (3) with a side wall (22). The connection portion of the upper half arch portion so that the contact surface 31 with the lower half portion of the connection portion 3 of the upper half arch portion is brought into contact with the upper surface of the side wall 22 of the lower half portion and a part of the inside of the tunnel. Reference numeral 3 denotes a structure in which the outside is cut out. This is a construction and a construction method of an arch culvert in which after filling the upper half arch portion, filling the notched portion 32 with the filling concrete 4 from outside the arch culvert to integrate the semi-precast arch culvert.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a semi-precast arch culvert having an arch culvert in which the lower half of the arch culvert is cast-in-place concrete including a bottom plate and side walls, and the upper half of the arch culvert is a precast concrete having an arch-shaped cross section. It concerns the construction method.
[0002]
[Prior art]
The conventional arch culvert is constructed by constructing the foundation c of the arch culvert a with cast-in-place concrete, and then supporting the shoring and constructing the arch portion constituting the side wall and ceiling of the arch culvert a with cast-in-place concrete. (See Patent Document 1). In addition, as a support for the arch portion, a support structure that can travel in the tunnel axis direction called an arch center b may be used (see FIG. 5).
The arch part has a curvature, and when constructing the arch part with cast-in-place concrete, assemble the shoring, attach the inner formwork and rebar with the curvature, and the outer formwork with the curvature After assembling, concrete is poured while managing the construction so that the concrete can be filled evenly.
Conventional arch culvert construction methods include a semi-precast arch culvert in which a precast arch part is erected on a foundation c constructed with cast-in-place concrete, in addition to the method of performing cast-in-place concrete as described above. (See Patent Document 2). According to the construction method of the semi-precast arch culvert, the connecting portion between the arch portion and the foundation c has a pin connection structure that does not transmit the bending moment.
[0003]
[Patent Document 1]
JP-A-11-323974 [Patent Document 2]
JP-A-2002-38502
[Problems to be solved by the invention]
The above-described conventional method of constructing an arch culvert has the following problems.
<B> If the arch part of the arch culvert is cast-in-place concrete, construction of the shoring and installation of inner formwork, reinforcing bars, outer formwork, etc. are required along with the construction of the arch part, making quality control difficult. Therefore, there is a problem that workability is not good.
<B> When the arch center is used as the shoring, the centr framing becomes the shoring and the centru framing itself becomes the work scaffold, so that the construction can be advanced while running the centru as the culvert is constructed. .
Therefore, when the arch center is used, efficient construction of the arch culvert can be realized.
However, the arc center is expensive and has a drawback that it is difficult to divert. For example, even if the arch center is used for construction of only one arch culvert of about 50 m, there is a problem that profitability is poor.
[0005]
[Object of the invention]
The present invention has been made in order to solve the conventional problems as described above, and when constructing the arch portion of the arch culvert, the structure of the arch culvert that does not require installation of excessive support or formwork and the like and its construction The aim is to provide a method. Another object of the present invention is to provide an arch culvert structure having a rigid connection structure, which can shorten a process and is excellent in workability, economy, and quality control, and a method of performing the same.
The present invention achieves at least one of these objects.
[0006]
[Means for Solving the Problems]
In order to achieve the above purpose, the lower half of the arch culvert is cast-in-place concrete consisting of a bottom slab and sidewalls provided substantially perpendicular to the bottom slab, and the upper half of the arch culvert is precast concrete with an arch-shaped cross section. In the structure of the semi-precast arch culvert according to the present invention, the wall of the precast concrete on the inner side of the tunnel is formed in advance, and the outer wall of the tunnel is provided with a notch at a connection portion connected to the side wall. It is a structure characterized by the following.
Further, in the structure of the semi-precast arch culvert, the reinforcing steel of the precast concrete exposed to the connecting portion side of the precast concrete and the reinforcing steel exposed to the connecting portion side of the cast-in-place concrete can be fixed to each other. can do.
Further, a method of constructing the semi-precast arch culvert for constructing the structure of the semi-precast arch culvert includes a lower half construction step of constructing the bottom slab and the side wall, and an upper half for erection at the connection portion of the precast concrete. A construction method comprising: a part erection step; and a connection part finishing step of arranging a tunnel axial reinforcing bar at the connection part and filling the notch with filling concrete.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0008]
<B> Semi-precast arch culvert An arch culvert is a concrete culvert whose upper section has an arch shape. In an ordinary box culvert having a rectangular cross section, the bending moment prevails on the ceiling, the bottom slab, and the wall due to the overburden load and the side earth pressure. On the other hand, in the arch culvert, it is possible to suppress the generated bending moment while changing the load into an axial force in the arch direction of the cross section. In particular, the position of the connecting portion 3 proposed this time is a position where only a small bending moment is generated. The generated bending moment is dominated by the negative bending moment, and a tensile stress always acts on the outside. These are the grounds for providing the connection portion 3 at this position. Note that the negative bending moment refers to a bending moment that generates a tensile stress above a member when, for example, a vertical load is applied downward to a horizontal member.
Of the arch culverts, the semi-precast arch culvert is a cast-in-place concrete for a lower half, which will be described later, including a bottom slab 21 and a side wall 22, and a precast concrete 1 for an upper half, which has an arch-shaped cross section, as described later. (See FIG. 1).
[0009]
In conventional arch culvert construction, after constructing the base concrete on the ground, assembling the shoring, or assembling the inner formwork with curvature by supporting the shoring using the arch centre. After assembling the outer formwork with curvature and assembling, concrete is poured into the space surrounded by the inner formwork and the outer formwork. According to such a method, it is necessary to process the formwork and the reinforcing bar so as to have a predetermined curvature, and there is a problem that it is difficult to control quality such as concrete filling property at the time of placing concrete in the arch part. .
Accordingly, the present invention provides a cast-in-place bottom slab 21 and a side wall 22 having no curvature in an arch culvert, and manufactures an upper half, which is difficult to cast in place, as a precast product in a factory or a site yard. By constructing the upper half on the lower half, a high-quality arch culvert can be constructed in a short period of time.
[0010]
Further, in order to solve the above problem, a conventional arch culvert structure includes a semi-precast arch culvert in which a foundation is constructed from cast-in-place concrete, and a precast arch portion is erected on the foundation. Such a semi-precast arch culvert has a pin connection structure in which the connection between the foundation and the arch does not transmit the respective bending moments. On the other hand, the features of the rigid connection structure include that there is no restriction on the procedure of the backfilling operation, that the connection portion 3 has a large tolerance in its manufacture, that it is easy, and that it is excellent in waterproofness.
In view of this, the present invention proposes a semi-precast arch culvert structure in which the connection portions 3 of the lower half and the upper half are rigidly connected.
After the arch culvert is completed, the arch culvert may be installed with the arch culvert exposed above the ground, or the arch culvert may be backfilled with buried soil to form a sewer. FIG. 4 shows an embodiment of an arch culvert provided so as to cross the embankment when the embankment is used as a road.
[0011]
<B> Lower half of the arch culvert The lower half of the arch culvert is composed of a bottom plate 21 and side walls 22, and is constructed of cast-in-place concrete.
When constructing the lower half, after constructing the bottom plate 21 of the culvert, the side wall 22 is raised substantially perpendicularly to the bottom plate 21. Therefore, in the lower half construction, there is no need for excessive support and no need to process a mold having a curvature.
The construction of the arch culvert is, for example, a method in which the construction of the lower half is completed over the extension of the tunnel over the construction ground, and thereafter, a plurality of upper halves having a predetermined width having a predetermined width are erected in the tunnel axial direction. Can be performed.
The cross-section direction reinforcing bar 23 is exposed from the upper surface of the side wall 22.
[0012]
<C> Upper half of the arch culvert The upper half of the culvert has a side wall and a ceiling of an arch-shaped culvert.
In the present invention, in order to improve workability, quality, and the like, the upper half uses precast concrete 1 manufactured in a factory or a site yard. That is, unlike the method of assembling the inner formwork, the reinforcing bar, and the outer formwork, and casting concrete to construct the upper half separately, taking the support to the shoring as in the prior art, for example, It is also possible to manufacture the upper half in parallel with the construction of the lower half, which facilitates quality control such as concrete filling. The width of the precast concrete 1 can be, for example, a length that can be easily transported, turned around on site, erected, and the like.
The connection part 3 in the upper half is formed as follows. That is, the inner side of the tunnel of the connecting portion 3 has a contact surface 31 that contacts the upper surface of the side wall 22 of the lower half so that the inner wall surface of the tunnel is formed when the upper half is erected on the lower half. It is constituted by the inner wall surface.
On the other hand, a cutout portion 32 is provided outside the tunnel of the connection portion 3, and the cross-sectional direction reinforcing bar 11 of the upper half portion is exposed in the cutout portion 32.
[0013]
<D> Connection Portion The connection portion 3 is a portion connecting the side wall 22 of the lower half and an upper half described later. The contact surface 31 of the connection portion of the upper half portion is brought into contact with the upper surface of the side wall 22 of the lower half portion and a part of the inside of the tunnel. That is, the connection part 3 in the upper half is provided with a notch part 32 which is formed so as to be cut out from a part of the contact surface 31 on the tunnel side and the connection surface 31 from the outside of the tunnel. The purpose of the notch 32 is to expose the cross-section direction reinforcing bars 11 and 23 from the ends of the connecting portions 3 in the upper half and the lower half so that they can be fixed to each other. Here, the term “fixing” means that the reinforcing bars of the upper half portion and the lower half portion side wall 22 exposed by a predetermined length are overlapped with each other. By the fixing of the reinforcing bar, the connecting portion can be formed to have a rigid connection structure. In addition, as shown in FIG. 2 (b), when it is confirmed that only a negative bending moment (a bending moment generated outside the cross section of the arch culvert) acts on the reinforcing bar shape of the connecting portion 3, a reinforcing bar joint only on the outside is used. It is also possible. In such a case, a simple structure can be obtained.
After the upper half contact surface 31 and the upper surface of the lower half side wall 22 are attached to each other and erected, a tunnel axial reinforcing bar 51 is provided, and the cutout portion 32 is filled with the filling concrete 4 to fill the upper half. Unit and the lower half. By providing the cut-out portion 32 outside the connection portion 3, since the post-filling concrete 4 is not exposed on the inner side surface of the arch culvert, the problem of peeling of the filling concrete 4 can be solved. 4 can be performed only from the outside of the arch culvert, so that the workability is good. The outer wall end of the joint between the filling concrete 4 and the precast concrete 1 or the side wall 22 and the end of the contact surface 31 on the empty side in the tunnel are provided with cutouts in, for example, trapezoidal or V-shape to provide elastic sealing for water stoppage. The material 53 and the like are filled.
After filling the outer wall edge of the joint between the filling concrete 4 and the precast concrete 1 or the side wall 22 with an elastic sealing material 53 or the like, a waterproof sheet 52 or the like is laid so as to cover the elastic sealing material 53, for example. Water effect can be further enhanced.
[0014]
Hereinafter, the construction method of the semi-precast arch culvert of the present invention will be described with reference to the drawings.
[0015]
The bottom slab 21 of the lower half of the arch culvert is constructed on the leveled construction ground, and the side wall 22 is constructed substantially vertically from the bottom slab 21 (lower half construction step) (see FIG. 3A). At this time, the construction of the lower half may be completed over the extension of the construction of the arch culvert.
The upper half of the arch culvert is manufactured at a factory or a site yard, and is erected by the heavy equipment 5 so that the contact surface 31 of the upper half is surfaced on the upper surface of the side wall 22 of the lower half (the upper half erection process). ) (See FIG. 3B).
The reinforcing bars 11 and 23 exposed at the upper and lower half connecting portions 3 are overlapped, a tunnel axial reinforcing bar 51 is provided, and the notched portion 32 is filled with the filling concrete 4 from outside the arch culvert. Thus, the upper half and the lower half are integrated (connecting part finishing step) (see FIG. 3C).
The connecting part finishing process is repeated over the extension of the arch culvert construction.
After completion of the connecting portion finishing step, cutouts are provided in, for example, trapezoidal or V-shaped notches at the outer wall end of the joint between the filling concrete 4 and the precast concrete 1 or the side wall 22 or at the end of the connecting surface 31 inside the tunnel. And an elastic sealing material 53 for stopping water. For example, a waterproof sheet 52 or the like is laid so as to cover the elastic sealing material 53 filled at the outer wall end of the joint between the filling concrete 4 and the precast concrete 1 or the side wall 22.
[0016]
【The invention's effect】
Since the structure of the semi-precast arch culvert of the present invention and the method of construction thereof are as described above, the following effects can be obtained.
<A> By precasting the upper half arch portion of the arch culvert, it is possible to shorten the construction period, secure quality, and improve workability.
<B> Since it is not necessary to use a support such as an arch center for the upper half construction, the construction cost is reduced as a whole.
<C> Filling concrete between the upper and lower halves can be filled only from the outside of the arch culvert, so workability is good, and no filling concrete is exposed inside the arch culvert. There is no possibility of peeling.
[Brief description of the drawings]
FIG. 1 is a perspective view of a semi-precast arch culvert according to the present invention.
FIG. 2A is a cross-sectional view illustrating a connection portion of a semi-precast arch culvert. (B) Sectional drawing explaining the Example of the reinforcement arrangement shape of a connection part when only a negative bending moment acts on a connection part.
FIG. 3A is an explanatory view showing an example of a lower half building step. (B) Explanatory drawing which showed the Example of the upper half part installation process. (C) Explanatory drawing which showed the Example of the connection part finishing process.
FIG. 4 is a perspective view showing an embodiment of an arch culvert.
FIG. 5 is a front view for explaining that an arch culvert is constructed at an arch center.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Precast concrete 2 ... Cast-in-place concrete 21 ... Bottom plate 22 ... Side wall 3 ... Connection part 4 ... Filling concrete

Claims (3)

A semi-precast arch culvert structure in which the lower half of the arch culvert is cast-in-place concrete composed of a bottom plate and side walls provided substantially perpendicular to the bottom plate, and the upper half of the arch culvert is a precast concrete with an arch-shaped cross section. ,
The precast concrete is characterized in that a wall inside the tunnel is formed in advance, and a wall outside the tunnel is provided with a cutout portion at a connection portion connected to the side wall,
Semi-precast arch culvert structure. The structure of a semi-precast arch culvert according to claim 1,
The precast concrete rebar exposed on the connection part side of the precast concrete, and the rebar exposed on the connection part side of the cast-in-place concrete are capable of being fixed to each other,
Semi-precast arch culvert structure. A construction method of a semi-precast arch culvert structure for constructing a semi-precast arch culvert structure according to claim 1 or 2,
A lower half construction step of constructing the bottom plate and the side wall,
An upper half erection step of erection at the connection part of the precast concrete,
A connecting part finishing step of arranging a tunnel axial reinforcing bar at the connecting part and filling the notched part with filling concrete.
Construction method of semi precast arch culvert structure.

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