JPH0754049B2 - Method of manufacturing precast PC structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a precast PC structure in which a floating structure made of concrete and precast concrete units such as culverts are connected and integrated.

[0002]

2. Description of the Related Art Conventionally, as a structure in which precast concrete units are connected to form an integrated unit, a utility model sho 60-60
The one disclosed in Japanese Patent Publication No. 063 is known.

[0003]

In the case of the structure in which the conventional concrete units are connected, since the precast concrete unit is made of reinforced concrete,
After the unit is manufactured at the factory, it is transported to the site where the unit is installed, and before the unit is connected with the connecting material, cracks occur due to the drying and shrinking of the concrete, and also when the unit is transported, there is an impact. The unit may crack when subjected to force. for that reason,
There is a problem that the length of one unit cannot be made large. Further, in the case of the precast concrete unit in the conventional structure, a through hole for inserting the connecting material in addition to the main rebar and the like must be provided in advance by using a sheath or the like, and therefore, at the manufacturing site. The work is complicated.

[0004]

In order to advantageously solve the above-mentioned problems, in the method of manufacturing a precast PC structure of the present invention, hollow PC steels are arranged over a plurality of abuts 1 arranged at intervals. In a state where the rod 2 is tensioned, a plurality of unit-constituent concretes 3 for embedding the hollow PC steel rods 2 are cast, and after the concrete 3 is hardened, the tension of the hollow PC steel rods 2 is released and precast Prestress is introduced into the concrete unit 4, and then the hollow PC steel rod 2 is cut near the end of the precast concrete unit 4 to obtain the precast PC member 5
And the tightening member 6 is inserted over the hollow PC steel rods 2 in the plurality of precast PC members 5 arranged in series and tightened.

[0005]

EXAMPLES Next, examples of the present invention will be described. First, as shown in FIG. 1 to FIG. 4, two concrete abutments 1 are fixed at intervals, and a plurality of formwork 7 are arranged in series between each abutment 1 and installed independently in the formwork 7. A foam block 8 made of a foamed hard foam synthetic resin is placed, and a plurality of upper and lower hollow PC steel rods 2 penetrating both left and right sides of each foam block 8 and both front and rear end plates of the mold 7 are attached to each abutment 1. The one end of each hollow PC steel rod 2 is engaged with the one abut 1 by a bearing fitting 9 that engages with the outer surface of the one abut 1 and a nut 10 screwed to the hollow PC steel rod 2. Stop.

The other end of each hollow PC steel rod 2 is inserted through the pressing metal fitting 11 and the center hole jack 12 engaged with the outer surface of the other abutment 1, and the other end of the hollow PC steel rod 2 is screwed. The fitted nut 13 is engaged with the piston 14 of the center hole jack 12, and each hollow PC steel rod 2 is tensioned by the center hole jack 12.

Next, as shown in FIG. 5, concrete 3 for unit construction is placed in the form 7, and the concrete 3
After being cured and cured for a predetermined period, the tension of the hollow PC steel rod 2 is released to introduce prestress to the precast concrete unit 4.

Next, the precast concrete unit 4
After the mold 7 is demolded, each hollow PC steel rod 2 is cut in the vicinity of the end of the precast concrete unit 4, and then the end surface treatment of the precast concrete unit 4 is performed to form the precast PC member 5. 6 to 11 show the completed precast PC member 5.

Next, the precast PC member 5 thus completed is carried to the assembly site of the structure, and the end faces of the precast PC members 5 arranged to face each other are elastic such as a rubber plate having a through hole. The plate 15 is fixed by an adhesive.

Next, a required number of precast PC members 5 are arranged in series, and hollow P in each precast PC member 5 is arranged.
The tightening member 6 made of a steel rod is inserted over the C steel rod 2, and the press washer 16 is fitted to the end of the tightening member 6 protruding from the precast PC member 5 and the tightening nut 17 is screwed. .

FIG. 15 shows another example of a connecting portion between the precast PC members 5, wherein one precast PC member 5A has a truncated conical projection 18 surrounding the end of the hollow PC steel rod 2. Is integrally provided, and the other precast P
The C member 5B is provided with a frustoconical recess 19 surrounding the end of the hollow PC steel rod 2, and one precast PC member 5 is provided.
The projection 18 of A is fitted into the recess 19 of the other precast PC member 5B, and each precast PC member 5A, 5B
The hollow PC steel rods 2 are arranged in series.

In the case of carrying out the present invention, the tightening member 6 may be made of glass fiber, aramid fiber, FRP, CFRP or the like in which a rod is connected to the end thereof.

When embodying the present invention, the hollow PC steel rod 2
Alternatively, a deformed hollow PC steel bar having a protrusion on the outer peripheral surface may be used. By using such a deformed hollow PC steel rod, the adhesive force with concrete can be enhanced.

[0014]

According to the present invention, hollow PC steel rods 2 arranged over a plurality of spaced abuts 1 are provided.
In the tensioned state, a plurality of unit-constituting concretes 3 for embedding the hollow PC steel rods 2 are cast, and after the concrete 3 is hardened, the tension of the hollow PC steel rods 2 is released, and the precast concrete unit 4 is prestressed, and then the hollow PC steel rod 2 is cut in the vicinity of the end of the precast concrete unit 4 to form a precast PC member 5, which is hollow in the plurality of precast PC members 5 arranged in series. Since the tightening member 6 is inserted and tightened across the PC steel rod 2, the precast PC member 5 having a large strength can be manufactured by a simple means, and therefore, the cracking of concrete can be prevented and the length of the precast PC member 5 can be prevented. Can be made longer than the conventional precast concrete unit, and the Since the hollow PC steel rod 2 is used in addition to the hollow PC steel rod 2, it is only necessary to place the reinforcing bar in addition to the hollow PC steel rod 2. Therefore, a sheath is used for the reinforcing work and the through hole for inserting the connecting material. Since it is not necessary to do so, it is possible to save a lot of labor. Further, since the hollow portion of the hollow PC steel rod 2 serves as a through hole for inserting the tightening member 6, unlike the sheath in the above-mentioned prior art, there is no risk of damage by a vibrator or the like during concrete pouring. Further, since each precast PC member 5 is connected by the tightening member 6 inserted in the hollow PC steel rod 2, the precast PC members 5 can be firmly and integrally connected.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a state in which a plurality of hollow PC steel rods are arranged in a tension state between abutments and a plurality of molds are installed. .

FIG. 2 is a vertical sectional side view showing a right end portion of FIG. 1 in an enlarged manner.

FIG. 3 is a vertical cross-sectional side view showing a left end portion of FIG. 1 in an enlarged manner.

FIG. 4 is a vertical cross-sectional side view showing an intermediate portion of FIG. 1 in an enlarged manner.

FIG. 5 is a vertical cross-sectional side view showing a state where concrete is placed in a formwork.

FIG. 6 is a vertical sectional side view showing a completed precast PC member.

7 is a cross-sectional view taken along the line AA of FIG.

FIG. 8 is a perspective view of a precast PC member.

FIG. 9 is a vertical sectional side view of an intermediate portion showing a precast PC member.

FIG. 10 is a perspective view showing a precast PC member for an end portion.

FIG. 11 is a vertical sectional side view showing an intermediate portion of a precast PC member for an end portion.

FIG. 12 is a vertical sectional side view showing an engaging portion of a tightening member with respect to a precast PC member for an end portion.

FIG. 13 is a vertical sectional side view showing a connecting portion between precast PC members.

FIG. 14 is a vertical cross-sectional side view showing the connecting portions of the precast PC members separated from each other.

FIG. 15 is a vertical cross-sectional side view showing another example of the connecting portion between the precast PC members.

[Explanation of symbols]

 1 Abut 2 Hollow PC steel rod 3 Concrete for unit construction 4 Precast concrete unit 5 Precast PC member 6 Tightening member 7 Formwork 8 Foam block 9 Bearing metal fittings 10 Nut 11 Pressing metal fitting 12 Center hole jack 13 Nut 14 Piston 15 Elastic plate 16 Press washer 17 Tightening nut 18 Protrusion 19 Recess

Claims (1)

[Claims] 1. A plurality of unit-constituting concretes 3 for burying the hollow PC steel rods 2 are placed in a tensioned state of the hollow PC steel rods 2 arranged over a plurality of abuts 1 arranged at intervals. After the concrete 3 is hardened, the tension of the hollow PC steel rod 2 is released, and prestress is introduced into the precast concrete unit 4, and then the hollow PC steel rod 2 is near the end of the precast concrete unit 4. Cut and precast PC member 5
And a method for manufacturing a precast PC structure in which the tightening member 6 is inserted and tightened across the hollow PC steel rods 2 in the plurality of precast PC members 5 arranged in series.