JPH0426379B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for pushing and fixing compressed steel bars placed in a concrete member in order to reinforce the compressed edges of the concrete member constituting a concrete structure. It is something.

[Prior art] In recent years, tensile steel is placed on the tensile edge of a concrete member to apply compressive stress to the tensile edge of the member.
Furthermore, a method was developed and implemented to obtain prestressed concrete members that can withstand large loads with a smaller member cross section by placing compression steel rods on the compression edges of concrete members and applying tensile stress to the compression edges of the members. ing. For convenience, this method will be referred to as the pipe restressing method.
When implementing the pipe restressing method, conventionally the following two methods have been used to press and fix the compressed steel rod.
method is known.

One method is the method disclosed in Japanese Patent Application Laid-Open No. 59-11804, in which, as shown in FIG. Plate-shaped steel pressure receiving member 17
and the sheath 18 is fitted in the concrete embedded part of the compressed steel rod 15, and the compressed steel rod 1
5 at a predetermined position in the formwork and pouring concrete, a concrete member 21 having a fixing recess 19 and a jack accommodating recess 20 located on the end face side of the concrete member is formed.
Next, a jack 22 is accommodated in the recess 20, a steel reaction force support plate 23 is interposed between the jack 22 and the side surface of the concrete member end face in the recess 20, and a compressed steel rod is manufactured. 15
Fit the steel pushing jig 24 screwed onto the end of the plunger in the jack 22, then extend the jack 22 and push the compressed steel rod 15 toward the center of the concrete member 21. Then, by rotating the fixing nut 16 and bringing it into close contact with the pressure receiving member 17, the return movement of the compressed steel rod 15 is prevented, and the end of the compressed steel rod 15 is fixed to the concrete member 2.
This is a method of fixing it to 1.

However, in the case of this fixing method, the compressed steel rod 15
There is a disadvantage that the concrete member 21 cannot be fixed at the end of the concrete member 21, and since the recesses 19 and 20 are provided in the middle part of the concrete member 21, there is a disadvantage that the cross section of the concrete member is lost and the cross section of the concrete member cannot be used effectively. Furthermore, since reinforcing the concrete member between the recesses is complicated, it is time-consuming and uneconomical.

Another method is the method disclosed in Japanese Patent Application Laid-Open No. 60-253661, in which a cylindrical steel intermediate fixing body 25 having a female thread for locking a compressed steel bar is used, as shown in FIG. The anchor member 27 inserted into the steel anchoring body 26 and fixed to the anchoring body 26 is embedded and fixed in the end of the concrete member 21, and the sheath 28
The end of the compressed steel rod 15 inserted into the intermediate fixing body 2
The compressed steel rod 15 is compressed by the jack 22 which is directly or indirectly supported by the bolt 5 and then supported by the jack support member 29 connected to the fixing body 26, so that the intermediate fixing body 25 is attached to the compressed steel bar 15. After the end of the compressed steel rod 15 is moved with the end thereof, the intermediate fixing body 25 is rotated with the end of the compressed steel bar 15 supported directly or indirectly by the jack 22, and the locking protrusion of the intermediate fixing body 25 is moved. 30 is engaged with the inner surface of the fixing body 26, and then the jack supporting member 29 and the jack 22 are removed.

This anchoring method avoids the disadvantage of cross-sectional loss in the middle of the concrete member, but it does not require compressed steel rods, that is, the areas where the compressive stress of the concrete member exceeds the allowable compressive stress of the concrete. The disadvantage is that it is not possible to place the compression steel rod only in the concrete member, and that the compression steel rod must be extended to the end of the concrete member, which necessitates an uneconomical design.

[Purpose and structure of the invention]

The purpose of this invention is to provide in-press fixation of compressed steel rods that eliminates the drawbacks of the above two methods, and the gist of this invention is to:
A fixing nut 2 and a pushing nut 3 located at the front thereof are screwed onto the end of the compressed steel rod 1, and a steel pressure receiving member 4 located at the rear of the fixing nut 2 is fitted. The compressed steel rod 1 is placed at a predetermined position in a formwork to produce a concrete member 6 having a fixing/pushing recess 5 for accommodating the fixing nut 2 and the pushing nut 3, and then a pushing jig is prepared. 7
The fixed locking arm 9 of the fixed member 8 for pushing and the movable locking arm 11 of the movable member 10 for pushing are inserted into the fixing/pushing recess 5 to connect the pushing nut 3 and the steel pressure receiving member 4. With the pushing jack 12 engaged with the pushing fixed member 8 and the pushing movable member 10, the pushing movable member 1 is
0 and a compression steel rod 1 through a pushing nut 3, and then the fixing nut 2 is engaged with a steel pressure receiving member 4. .

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

When carrying out this invention and fixing a compressed steel rod inserted into a concrete member by pushing it, first, as shown in FIGS. 1 and 2, a sheath 13 is fitted into the concrete embedded part of the compressed steel rod 1. , and a steel pushing nut 3 is screwed onto the end of the compressed steel bar 1, and a steel plate pressure receiving member is engaged with the rear surface of the pushing nut 3 (the surface on the end surface side of the compressed steel bar 1). 1
4, then a steel fixing nut 2 is screwed onto the end of the compressed steel rod 1, and a plate-shaped steel pressure receiving member 4 is fitted, and then the compressed steel rod 1 is attached to a concrete member. A concrete member 6 having a fixing/pushing recess 5 which is placed at a predetermined position in a forming form and accommodates a fixing nut 2, a pushing nut 3, and a steel plate pressure receiving member 14 is manufactured, and a steel pressure receiving member 6 is manufactured. The member 4 is embedded in the rear part of the fixing/pushing recess 5.

In this case, the distance L from the front surface of the steel pressure receiving member 4 (intermediate surface of the compressed steel bar) to the end face of the compressed steel bar 1
1 is set to a length equal to the length of the thickness of the steel pressure-receiving member 4 added to the amount of shortening when the compression steel bar 1 is completely pushed in, and the length of the pushing nut 3 before pushing the compression steel bar 1 is set. The distance L2 between the front surface and the front surface of the fixing/pushing recess 5 is set to be larger than the shortening amount when the compression steel bar 1 is completely pushed in, and the pushing nut 3 is Avoid hitting the front surface of the fixing/pushing recess 5.

Next, in the pushing jig 7 consisting of the fixed member 8 for pushing and the movable member 10 for pushing, which are slidably fitted together, the jack receiving part of the fixed member 8 for pushing and the jack receiving part of the movable member 10 for pushing are connected. The pushing jack 12 is interposed between them and they are fixed with bolts, and the fixed locking arm 9 of the pushing fixed member 8 and the movable locking arm 11 of the pushing movable member 10 are fixed in the fixing/pushing recess 5. , and while the fixed locking arm 9 is engaged with the steel pressure receiving member 4 and the movable locking arm 11 is engaged with the steel plate pressure receiving member 14, the pushing jack 12 is extended. As a result, the compressed steel rod 1 is pushed toward the center of the concrete member 6.

In this case, the jacking reaction force is transmitted to the concrete member 6 via the pushing fixing member 8 and the steel pressure receiving member 4.
The fixing nut 2 moves in a direction away from the steel pressure receiving member 4 as the compressed steel rod 1 shortens.

Next, rotate the fixing nut 2 to release the steel pressure receiving member 4.
By bringing the compressed steel rod 1 into close contact with the steel pressure receiving member 4, the return movement of the compressed steel rod 1 is prevented, and the end of the compressed steel rod 1 is brought into close contact with the steel pressure receiving member 4.
It is fixed to the concrete member 6 via.

Next, after shortening the pushing jack 12 and removing the movable locking arm 11 from the steel plate pressure receiving member 14, the pushing jig 7 is removed, and then, as shown in FIG. From the injection tube 31 to the sheath 1
Mortar grout 32 is injected into 3, and post-filling concrete 33 is filled into the fixing/pushing recess 5 to complete the construction.

In addition, in FIG. 1, 34 is a tensile steel material inserted into the sheath 35 on the tensile side of the concrete member 6.

The present invention can also be implemented by pressing a compressed steel rod into a prestressed concrete member using a pretensioning method. Further, as a means for preventing adhesion when a compressed steel rod is embedded in concrete for forming a concrete member, an inhibitor such as grease or asphalt may be applied in advance to the circumferential surface of the compressed steel rod 1 without using a sheath.

When implementing this invention, the steel plate pressure receiving member 14
may be omitted, and the movable locking arm 11 of the movable pushing member may be directly engaged with the rear surface of the pushing nut 3.

〔Effect of the invention〕

According to the present invention, the fixing nut 2 and the pushing nut 3 located at the front part thereof are screwed onto the end of the compressed steel rod 1, and the steel pressure receiving member 4 located at the rear part of the fixing nut 2 and placing the compressed steel rod 1 at a predetermined position in the formwork to manufacture a concrete member 6 having a fixing and pushing recess 5 that accommodates the fixing nut 2 and the pushing nut 3, Next, the pushing fixing member 8 in the pushing jig 7
The fixed locking arm 9 and the movable locking arm 11 of the movable pushing member 10 are inserted into the fixing and pushing recess 5 and arranged between the pushing nut 3 and the steel pressure receiving member 4. Then, the compressed steel rod 1 is pushed through the movable pushing member 10 and the pushing nut 3 by the pushing jack 12 engaged with the fixed member 8 for pushing and the movable member 10 for pushing, and then the fixing nut is 2 is engaged with the steel pressure-receiving member 4, the compressed steel rod 1 can be pushed and fixed without providing a large recess in the concrete member 6 for accommodating a pushing jack. It is possible to reduce cross-sectional defects at the end of the compressed steel rod 1, and to easily perform the fixing operation of the compressed steel rod 1. Furthermore, the number of recesses provided in the concrete member 6 at the end of the compressed steel rod 1 is one. Compared to the above-mentioned conventional case in which two recesses are provided in the concrete member at the end of the compressed steel bar, there is no need to reinforce between the recesses, which saves time and reduces the need for reinforcing materials, making it more economical. Furthermore, since the compressed steel rods 1 can be installed only in the necessary sections of the concrete member 6, effects such as being economical can be obtained.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, in which Figure 1 is a schematic vertical sectional side view showing the arrangement of tensile steel members, compression steel bars, and push-in fixing parts in a concrete member, and Figure 2 3 is a longitudinal sectional side view showing a state in which a pushing jig operated by a pushing jack is set in the pushing fixing part, FIG. 3 is a sectional view taken along the line A-A in FIG. 2, and FIG. FIG. 3 is a longitudinal sectional side view showing a state in which mortar grout is injected into the sheath after pressing and fixing is completed, and the recess is filled with post-filling concrete. FIG. 5 and FIG. 6 are longitudinal sectional side views for explaining a conventional press-fixing method for compressed steel material. In the figure, 1 is a compressed steel rod, 2 is a fixing nut, 3 is a pushing nut, 4 is a steel pressure receiving member, 5 is a fixing and pushing recess, 6 is a concrete member, 7 is a pushing jig, and 8 is a pushing jig. A fixed member for pushing, 9 a fixed locking arm, 10 a movable pushing member, 11 a movable locking arm, 1
2 is a pushing jack, 13 is a sheath, 14 is a steel plate pressure receiving member, 32 is mortar grout, and 33 is post-filled concrete.

Claims (1)

[Claims] 1. At the end of the compressed steel rod 1, screw the fixing nut 2 and the pushing nut 3 located at the front thereof, and fit the steel pressure receiving member 4 located at the rear of the fixing nut 2, The compressed steel rod 1 is placed at a predetermined position in a formwork to manufacture a concrete member 6 having a fixing/pushing recess 5 for accommodating the fixing nut 2 and the pushing nut 3. The fixed locking arm 9 of the fixed member 8 for pushing and the movable locking arm 11 of the movable member 10 for pushing in the tool 7 are inserted into the fixing/pushing recess 5, and the pushing nut 3 and the steel pressure receiving member are inserted. 4, the compressed steel rod 1 is pushed through the movable member 10 and the nut 3 by the pushing jack 12 engaged with the fixed member 8 for pushing and the movable member 10 for pushing. A method of fixing a compressed steel bar for a prestressed concrete member by pushing it in, and then engaging the fixing nut 2 with a steel pressure receiving member 4.