JPH06248613A - Construction of bridge pier - Google Patents

Abstract

PURPOSE:To reduce the construction period, by stacking required numbers of precast box culverts having large and small openings to form the external frame of a bridge pier and placing underwater concrete in the inside thereof to construct the pier. CONSTITUTION:Required numbers of precast box culverts 1 having a large opening are stacked together with precast box culverts 2 having a small opening to form the external frame of a bridge pier. The clearance of the joint between the large opening culvert 1 and the culvert is closed by a cover plate 4, Next underwater concrete is placed in the culverts 1, 2 without use of underwater forms and also without flowing-out concrete to construct a bridge pier. In this way, the construction period is reduced and the environmental pollution is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pier construction method.

[0002]

2. Description of the Related Art As a conventional method for constructing a bridge pier, a method of assembling a formwork on site and placing underwater concrete in the formwork is the mainstream. Most of the assembling and demolding of the formwork at this site are underwater work, so the workability is poor. Furthermore, when assembling the molds by underwater work, a gap is created between the molds, and if the site is where there is a water flow, the placed underwater concrete may be washed and the cement content may be washed away, resulting in underwater concrete with defective parts. is there. In addition, the sea and rivers will be polluted by the spilled cement.

In order to avoid such a drawback, it is possible to adopt the caisson method, but the caisson method requires a large amount of construction work, resulting in a significant increase in construction cost.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for constructing a bridge pier by which a stable underwater concrete can be placed by a simple operation without polluting the environment.

[0005]

According to the present invention, a large opening precast box culvert in which four guide rails are provided on an inner wall along an axial direction and a part of an upper surface opening is covered with a cover plate is provided at a predetermined position on the water bottom. Install so that the guide rail is vertical, stack a specified number of small opening precast box culverts on the large opening precast box culvert along the guide rail, and then add underwater concrete in the space surrounded by the precast box culvert. It is a method of constructing a pier characterized by placing it.

The present invention makes use of a precast box culvert, which is generally considered as a structural material for constructing a waterway, as a formwork for a bridge pier, thereby eliminating the need for an underwater formwork and almost eliminating underwater work. Precast box culvert is a factory product, so there is almost no gap between each other when stacking precast box culverts, and there is almost no runoff of the poured underwater concrete, so only stable underwater concrete can be poured. It does not pollute the environment.

Further, the construction is simple, such as installation of precast box culverts, stacking and placing of underwater concrete, and the construction period is shortened.

As for the large opening precast box culvert used in the present invention, if it is produced, the produced product may be used as it is. If the produced product is not produced, the two-division type is produced. For example, two pieces of the two-division type product may be connected and used. In the present invention,
The wall end surface of the small opening precast box culvert is stacked on the wall end surface of the large opening precast box culvert, and the wall end surface of the small opening precast box culvert is stacked and stacked. Small-aperture precast box Use the same length as the long side of the culvert opening.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIGS. 1, 2, and 3 are an elevation view, a side view, and a plan view, respectively, showing a state of a bridge pier constructed according to the present invention before underwater concrete placement, and FIGS. 4 and 5 are A-A. It is sectional drawing and BB sectional drawing.

A large opening precast box culvert 1 is manufactured by connecting two two-division type precast box culverts with a joint fitting 5, and a guide rail 3 is provided on the inner wall of the precast box culvert 1.
4 are attached in the vertical direction, and a cover plate 4 for closing the opening portion that is not closed when the small opening precast box culvert 2 is loaded is attached to the upper end of the large opening precast box culvert 1. Cover plate 4
Is preferably an L-shaped elastic plate and is attached so as to cover the upper opening of the large opening precast box culvert 1 and the outer wall surface of the small opening precast box culvert 2.

This large opening precast box culvert 1 is suspended and installed at a predetermined place on the bottom of the water. At this time, it is preferable that a soft elastic body such as a polyurethane foam is attached to the lower surface of the large opening precast box culvert 1 so as to fill the gap between the lower surface of the large opening precast box culvert 1 and the water bottom. .

Large opening precast box culvert 1
After the installation is completed, the small opening precast box culvert 2 is hung while the inner wall of the small opening precast box culvert 2 is laid along the guide rail 3 and stacked on the large opening precast box culvert 1. Also in this case, in order to fill the gap, it is preferable to attach a soft elastic body to a necessary portion on the lower surface of the box culvert 2. In this way, the small opening precast box culverts 2 are stacked until the predetermined height is reached.

After the stacking is completed, underwater concrete is poured into the space inside the precast box culvert, and then the pier head is normally constructed.

[0015]

By utilizing the precast box culvert as the formwork of the pier, the underwater formwork becomes unnecessary and the underwater work is almost eliminated. There is almost no gap between the precast box culverts when they are stacked, and the poured underwater concrete is hardly washed away, so that not only stable underwater concrete can be poured but also the environment is not polluted.

[Brief description of drawings]

FIG. 1 is an elevational view showing a state in which a pier is constructed.

FIG. 2 is a side view showing a state in which a pier is constructed.

FIG. 3 is a plan view showing a state in which a pier is constructed.

FIG. 4A is a sectional view taken along line AA, and FIG. 4B is taken along line BB.
FIG.

[Explanation of symbols]

1 ... Large opening precast box culvert, 2 ...
Small opening precast box culvert, 3 ... guide rail, 4 ... cover plate, 5 ...

Claims (1)

[Claims] 1. A large opening precast box culvert in which four guide rails are provided on an inner wall along the axial direction and a part of an upper surface opening is covered with a cover plate so that the guide rails are vertically arranged at predetermined positions on the water bottom. It is characterized by placing a predetermined number of small opening precast box culverts on the large opening precast box culvert along the guide rail and then placing underwater concrete in the space surrounded by the precast box culvert. How to build a pier