JPH04136335A - Prestress introduction method for box segment - Google Patents

Abstract

PURPOSE:To enable tension to be easily applied by providing a PC steel material around a concrete segment having a square sectional form, temporarily tensioning the steel material, and then pushing outward a pin material at both bottom corners for finally tensioning the steel material. CONSTITUTION:A top slab 1, a bottom slab 2, a side slab 3 and corner slabs 4 and 5 respectively comprising a concrete segment, are assembled into a square cylindrical form, thereby forming a box cement 6. Also, a PC steel material 7 is laid around the segment 6, and connected with a jointing tool 8 and temporarily tensioned, thereby jointing each segment 1 to 5. Thereafter, prestressing members 12 at both bottom corner slabs 5 are pushed externally, thereby tensioning the PC steel material 7. According to the aforesaid construction, a prestressing work can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for introducing prestress into box segments, which is suitable for use in constructing sewers, public ditches, underground passages, and the like.

[Prior Art] Concrete culverts, which are generally used when constructing sewers, public ditches, underground passages, etc., are formed into a rectangular tube shape with openings at both ends, and joints provided at each opening at both ends. It is a structure that connects sequentially using .

[2] Problems to be Solved by the Invention] By the way, box-shaped culverts and the like have a box-shaped shape, so they have an extremely high space utilization rate compared to the circular Nundrud tunnel, but on the other hand, In deep tunnels such as those created using the shield method, when comparing a circular cross section and a box cross section designed under the same civil engineering conditions, the circular cross section, which is inferior in space utilization, has the property of being more economical (lighter structure). Because of this, they have traditionally been installed in areas with shallow soil cover that could be achieved using open-cut construction methods.

Therefore, in deep tunnels formed by the shield construction method, circular segments are economically advantageous because they have a lighter structure than box-shaped culverts, etc., and are often used. The reality is that there are.

The present invention has been made in view of these circumstances, and aims to lighten the structure by applying an axial force to the box segment, so that the box segment can be applied under the same civil engineering conditions as circular segments. The purpose of the present invention is to provide a method for introducing prestressing into a box segment that has been strained so that the stress can be increased.

[Means for Solving the Problems] In claim 1, the present invention provides that, after assembling concrete segments into a rectangular tube shape to form a box segment having at least four corners, the box segment is provided with an inner surface of the box segment. ■What is the span direction of each concrete segment? The PCfII4 material along this is spanned through the pin material located at the corner of the concrete segment, its both ends are temporarily tightened and joined with a connector, and then the PCfII material is placed at the corner of both ends of the bottom. The solution was to slide the pin material outward to tension the PC steel material and apply prestress to the box segment.

Further, in claim 2, when assembling concrete segments into a square tube shape to form a box segment having at least four corners, each concrete segment is preliminarily coated with PCA material along the span direction of each concrete segment. At the same time as each concrete segment is assembled, the joints of these PCII materials are temporarily tightened using connectors, and then the PC steel materials are pushed outward at the corners of both ends of the bottom to tension the PC steel materials. The solution was to apply prestress to the box segments.

[Function] According to the method for introducing prestress into a box segment according to claim I of the present invention, after temporarily tightening the prestressing steel material with a connecting tool, tension is applied to the prestressing steel material via the pin material at the corners of both ends of the bottom. This applies tension to the PCIli material, so axial force is applied to the PC steel material due to both the temporary tightening by the connector and the tension of the PC steel material, and a high prestress is applied to the box segment. will be introduced.

Furthermore, according to the method for introducing prestress into box segments according to claim 2, the joints of the PC steel materials buried in each concrete segment are temporarily tightened simultaneously with the formation of the box segments without using pin materials. Since it is joined, it becomes easy to attach the PC steel material to the box segment.

Further, since the PCjl material is tensed by directly pushing the PC steel material without using the pin material, the operation for introducing prestress into the box segment is simple.

[Examples] Hereinafter, the present invention will be described in detail by showing examples and with reference to the drawings.

1 to 3 show a method of introducing prestress into a box segment according to claim 1.

First, a box segment 6 is formed by joining four types of concrete segments into a rectangular tube shape.

The four types of concrete segments used at this time are:
Specifically, they are a top plate part 1, a bottom plate 112, both side plate parts 3.3, and a corner plate 414, 4°5.5 including four corner corners. The bottom plate part 2 has a box cutout part 2a on the inner surface near the center part.
In addition, four corner plates 4.4 are used.
．． 5.5 is bent into an abbreviated shape and has notched surfaces 4a, 4a, 5B, and 5a on the inner surface of the corner. In addition, these corner slabs 4.4.5.5 are made of 5RC (made of steel reinforced concrete) structure in advance in consideration of applying high tension.

In addition, concrete segments (top plate part l, bottom plate part 2,
Both sides 3, 3 and corner 4.4.5.

5), grooves Ib, 2 are preliminarily formed on each inner surface and approximately at the center in the width direction, each extending in the span direction.
b, 3 b, 3 b, 4 b, 4 b, 5
b, 5b are formed, top plate part l, bottom plate part 2,
Both sides 3.3 and corner 4. ．． When joining 4 and 5.5, the respective grooves 1b, 2b, 3b, 3b, 4b
, 4 b, 5 b, 5 b are continuous to form one annular groove 6b.

In this groove 6b, P is used to give a certain stress state (prestress) to the box segment 6.
Bury C steel material 7.

The end of PC@ClO2 is fermented in the box cutout 2a provided in the bottom plate 2 of the box segment 6. Both ends of the PCII material 7 are threaded in advance, and the threaded portions are tightened into a coupling tool (coupler 8) to temporarily join the PC steel material 7.

Next, bottle materials 9. are placed along the inner surface of the PC steel material 7 at the corners of the corner plate portions 4°4 located on both sides of the top plate portion l.
Insert 9. As the pin material 9, a round rod-like material having a predetermined diameter can be used, or a pipe-like material can also be used. Prior to inserting the pin material 9, a hole lO for inserting the pin material that penetrates in the width direction is made in advance at a predetermined position of the corner block portion 4 to a size that allows rotation of the pin material 9. Form it. And these holes 10
By inserting the pin member 9 into the PCaCaO2 surface, the PCaCaO2 surface is pressed outward.

Next, in the same manner as before, pin materials 1111 are inserted into the corners of the corner plate parts 55 located on both sides of the bottom plate part 2, so that the PCA material 7 is pressed outward, but at this time, This pin material 11 is pressed outward at right angles to the haunch surface 5a of the corner block portion 5 to apply tension to the PC steel material 7,
A prestress applying member 12 for introducing prestress into the box segment 6 is attached.

The prestressing member 12 has a bottomless cylindrical shape as shown in FIG. 3, and has a trapezoidal female thread formed on its inner surface. Furthermore, slits 1313 are provided at both ends in the diametrical direction of one end surface of the prestress applying member 12, and extend toward the other end surface. The width of this slit 13 is such that the PC steel material 7 can be inserted therein. Further, in the side surface of this prestressing member 12, there is an oblong hole 1 that penetrates in a diametrical direction perpendicular to the diametrical direction in which the slit 13.13 is provided, and into which the pin material 11 is loosely inserted.
4.14 is provided. This oval hole 14 has an elongated oval shape in the length direction of the prestress applying member 12, and its major diameter is set to a size that allows the pin material II loosely inserted into the oval hole I4 to move to some extent. .

Then, the prestressing member 12 having such a shape is attached to the corner of the corner plate portion 5 with its length direction facing diagonally outward from the haunch surface 5a. At this time, the slit + of the prestress applying member 12
3. Insert the PC steel material 7 into 13,
The pin material +1 is inserted into the oblong hole 14.14, and the pin material II is attached so that it is almost in contact with the inner surface of the PC steel material 7.

Further, a screw member 15 is tightened into the prestressing member 12 from the end thereof facing the haunch surface side. The screw member 15 has a trapezoidal male screw on its outer surface. The screw member 15 is tightened using a hydraulic unit of a shield machine (not shown). As the screw member 15 is tightened in this manner, the tip of the screw member 15 presses the pin material 11 inserted into the oblong hole 14.14 outward, thereby causing the pin material It to push the PC steel material 7 outward. Press to apply tension to the PCB material 7.

In this way, an axial force is applied to the PC steel material 7, and a prestress is introduced to the box segment 6.

At this time, by appropriately adjusting the tightening amount of the screw member 15, it is possible to arbitrarily adjust the magnitude of the axial force applied to the PC steel material 7 and the magnitude of the prestress introduced to the box segment 6. be.

As described above, according to the box segment prestress introduction method of this embodiment, after the both ends of the PC steel material 7 are temporarily joined by the coupler 8, the corner plate parts 4, 4 located on both sides of the top plate part l are At the corners, the PC steel material 7 is spanned via the pin material 9.9, and furthermore, at the corners of the corner plate LIe5.5 located on both sides of the bottom plate part 2, the prestress applying members 12.12 are placed. The pin materials II and 11 are tightened outward perpendicularly to the haunch surfaces 5a and 5a, and the PC steel material 7 is tensed by the pin materials 11 and 11, so that the PC
An axial force is applied to the sea bream material 7, and a high prestress is introduced to the box segment 6. Therefore, even in the box segment 6, as in the circular segment,
Axial force can be used as the generated cross-sectional force, and the resistance can be improved. Therefore, the structure of the box segment 6 can be made light, and the economical efficiency can be improved. Since the box segment 6 has a rectangular box shape, its space utilization rate is originally high, and when this is taken into consideration, the improvement in economic efficiency is remarkable.

Further, the magnitude of the axial force applied to the PC steel material 7 depends on the degree of temporary tightening of both ends of the PC steel material 7 by the coupler 8 and the amount of tightening of the PCM material 7 by the prestress applying member I2. , the desired stress state (
By adjusting these appropriately according to the prestress (prestress), a box segment 6 having an arbitrary prestress can be obtained.

Next, another embodiment of the method for introducing prestress into a box segment according to claim 1 will be described with reference to FIG.

This embodiment differs from the previous embodiment mainly because, in the above embodiment, the concrete segment is a top plate section 11, a bottom section section 2, both side section sections 3, 3, and a corner section section 4.4 which includes four corners. .5.5 was used, whereas the box segment 6 was formed using only the corner section 44.5.5 including four corners.

Further, in the above embodiment, each corner plate portion 4.4.5.

Although the example in which one pin material 9, 9, 11. Now, insert the 3 pieces).

In this case, the prestress imparting member 12.12 is attached to the middle pin of the three pins at the corner of the corner section 5.5, and the prestressing member 12.
1 is tightened by this prestress applying member 12.12.

Next, claim 2 of the present invention will be explained with reference to FIGS. 5 to 7.

FIG. 5 shows an embodiment of the method for introducing prestress into a box segment according to claim 2.

This embodiment is different from the embodiment of the method for introducing prestress into a box segment according to claim 1, as follows:
Mainly, when forming the box segment 6, a concrete segment (corner section 4, 4° 5.5) with pre-embedded PC steel material 7.7.7 is used, and a pin material is not used. This is the point of directly tensioning the PC steel material 7.7.7.7.

Specifically, this example will be explained in the order of steps. First, concrete segments are joined to form a square cylindrical box segment 6.

At this time, a corner block section 4.4.5.5 including four corners is used as a concrete segment, and each corner section 4.4.5.5 has an unforeseen span direction. The source tube along
7. Buried in an open state, and the source tube 16.
A structure in which PC steel material 7.7.7.7 is inserted into 16 and 16.16 is used. Further, at the corners of the two corner plates 5, 5 forming the bottom of the box segment 6, cylindrical simple jigs 18 1 are respectively provided which open on the inner side.
8 is buried. This cylindrical jig 18 is provided with a female thread 19 on the inner surface of the end of the box segment 6 facing toward the inner surface.

Then, these concrete segments (corner section 4
, 4.5.5), align the box-cut parts 17 and 17, and insert each PC steel material 7 in the box-cut part 7.
．． The end portions (joint portions) of 7 are temporarily tightened and joined using a coupling tool (coupler 8) to assemble into a square tube shape.

Next, the prestressing member 20 is screwed into the cylindrical jig 18 from the inner surface of the box segment 6 at both corners of the bottom thereof.

As shown in FIGS. 6 and 7, this prestress applying member 20 includes a male screw portion 21 that is screwed into the female screw portion 19 of the simple jig 18, and a male screw portion 21 provided at one end of the male screw portion 21. It has an operating part 22 for performing a screwing operation, and a pushing part 23, which is provided at the other end of the male screw part 21 and pushes the PC steel material 7 outward. This pushing part 23
A groove 24 is formed on the end face of the box segment 6 to take in the PC1i material 7 at the corner j of the box segment 6 and push it outward. This groove portion 24 extends in the diametrical direction of the push-in portion 23, and is formed to gradually become deeper as it approaches both ends in the diametrical direction.

After screwing the male screw part 21 of the prestress applying member 20 to the female screw 19 of the cylinder jig 18 and taking the PC steel material 7 into the groove part 24 provided in the pushing part 23, this prestress applying member 20 Gradually screw in the male thread part 2I.
The depth of the screw engagement of the female screw portion I9 is gradually deepened. As a result, the PC steel material 7 is gradually pushed outward to apply appropriate tension.

In this way, according to the box segment prestress introduction method of this embodiment, each concrete segment (
At the same time, the corner plates 4.4.5.5) are joined to form the box segment 6, and at the same time, the PC steel members 7, 7° 7.7 buried in each corner plate 4, 4.5.5 are joined. Since the prestress applying member 20 is pushed in to tension the PC@ material 7 after temporarily tightening and joining, an axial force is applied to the PC steel material 7 and prestress is introduced into the box segment 6. Therefore, similarly to the method for introducing prestress into a box segment according to the first aspect, it is possible to reduce the structure of the box segment 6 and improve economical efficiency.

In addition, in this embodiment, the PCw4 material 7 is buried in the concrete segment (corner section 4.4.5.5) in advance, and these PCII materials 7, 7, 7. Since the joint portions 7 are joined by temporary tightening, it becomes easier to attach the PC steel material 7 to the box segment 6, compared to the box segment prestress introduction method described in claim 1. In addition, by directly pushing the PC sea bream material 7 without using bottle material, P
Since the C steel material 7 is tensed, the operation of introducing prestress into the box segment 6 is very simple.

In addition, in this embodiment, PC
Since couplers 88, 8, and 8 are provided for temporarily joining the steel materials 7, the tension is introduced into the PC steel material 7 or is distributed over the entire length of the PCM material 7, and the tension is uniformly applied to the box segment 6. However, prestress is introduced.

Note that the method of introducing prestress into a box segment of the present invention is not limited to the above-mentioned embodiments, and can be applied to
Specific configurations such as work procedures can be changed as appropriate during implementation.

For example, this method of introducing prestress into a box segment is not limited to the rectangular cylindrical box segment 6, but can also be applied to other polygonal cylindrical segments.

Further, in the embodiment, the prestress applying member 12.2
0, we have described an example using a shape as shown in Fig. 3 or Fig. 6.7, but any configuration in which it is possible to tension the PC steel material 7 and apply axial force to it is possible. ,
A shape other than this may also be used.

Further, the number of PCm members 7 is not limited to one as shown in the above embodiment, but the number can be increased depending on the desired axial force.

``Effects of the Invention'' As explained above, according to the method for introducing prestress into a box segment according to claim 1 of the present invention, after joining concrete segments to form a box segment, the PCM material is connected by a connecting tool. After temporarily tightening the joint, tension is applied to the PCA material through the pin material at the corners of both ends of the bottom part to make the PC steel material tense, so an axial force is applied to the PC steel material, and a high prestress is applied to the box segment. Therefore, even a box-shaped segment can have an axial force as a generated cross-sectional force, and the resistance earth pressure can be improved. The structure can be made lighter, improving its economic efficiency.

In addition, the magnitude of the axial force applied to the prestressing steel depends on the degree of temporary tightening of the prestressing steel by the connector and the amount of push-in of the pin, so it can be applied to the desired stress state (prestress). Please adjust these accordingly.
A box segment with a prestress of [ can be obtained.

Furthermore, according to the method for introducing prestress into a box segment according to claim 2, when forming a box segment, a concrete segment formed by embedding prestressed steel material in advance is used, and a prestressing method is directly applied without using a pin material. PCp
Since the material is pushed in and tensioned, it becomes easy to attach the prestressing steel material to the box segment, and the operation of pushing the prestressed steel material becomes very simple. Note that the effect of improving economical efficiency by reducing the structure of the box segment is similar to the method for introducing prestress into a box segment according to claim 1 described above.

[Brief explanation of the drawing]

1 to 3 are for explaining an embodiment of the method for introducing prestress into a box segment according to claim 1 of the present invention, and FIG. 1 is a sectional view of the box segment, and FIG. 2 is a sectional view of the box segment. 3 is a state diagram showing the bottom of the box segment viewed from the inner side, FIG. 3 is a perspective view showing the configuration of the prestress applying member, and FIG. This shows another embodiment of the method, and is a sectional view of a box segment, and FIGS. 5 to 7 show an embodiment of the method for introducing prestress into a box segment according to claim 2 of the present invention. FIG. 5 is a sectional view of the box segment, and FIGS. 6 and 7 are a bottom view and a side view, respectively, showing the structure of the pushing part of the prestressing member. 1...Top plate part (concrete segment), 2
...Bottom section (concrete segment), 3...
...Side section (concrete segment), 4.5.
...corner section (concrete segment), 6.
... Box segment, 7 ... PC steel material, 8 ... Coupler (connecting tool), 9.11 ...
...Pin material, 12.20...Prestress imparting member. Applicant Ishikawajima Kenzai Kogyo Co., Ltd. Toda Construction Co., Ltd. Figure 1 Figure 4

Claims (2)

[Claims] (1) After assembling concrete segments into a rectangular tube shape to form a box segment having at least four corners, a prestressing steel material is attached to the box segment along the span direction of each concrete segment from the inner surface of the box segment. It is spanned through pins located at the corners of the concrete segment, its both ends are temporarily tightened with a connecting tool, and then, at the corners at both ends of the bottom, the pins located at the corners are pushed outward. A method for introducing prestress into a box segment, characterized by applying prestress to the box segment by sliding the prestressed steel material under tension. (2) When assembling concrete segments into a rectangular tube shape to form a box segment having at least four corners, each concrete segment is pre-buried with prestressing steel along the span direction of each concrete segment. At the same time as the concrete segment is assembled, the joints of these prestressed steel materials are temporarily tightened using connectors, and then the prestressed steel materials are pushed outward at the corners of both ends of the bottom to tension the prestressed steel materials, and the box segments are assembled. A method for introducing prestress into a box segment, which is characterized by applying prestress to a box segment.