JPS5938013A - Method and device for giving torus-shaped structure prestress - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a prestressed concrete structure, particularly a steel material for prestressed cleats (hereinafter referred to as PCil material) placed along the periphery of an annular concrete wall, at a midpoint of the structure. The present invention relates to a method of fixing the wall under tension and an apparatus for carrying out the method of the present invention.

When an annular concrete wall such as a concrete tank or tunnel is subjected to internal pressure due to a substance such as a liquid placed inside the wall, a flexible Place the PC steel material,
It has been well known to systematically apply stress to a concrete wall so as to correspond to the stress caused by the pressure and the like.

Conventionally, a wedge-based fixing device has been mainly used as a fixing method for the above-mentioned flexible prestressing steel material, and in order to fix the device in a concrete wall, a protrusion or cavity is provided, and the surrounding concrete is strengthened. has been taught.

Compared to those arranged in a straight line, these PC steel materials arranged in an arc have significantly greater friction loss due to angular changes along the circumference, so the total circumference length is divided into several equal parts. A method of dividing and fixing is commonly used. Therefore, each PC steel material is fixed at a considerably shorter length than the circumference.

What is important to note is that in conventional wedge force type fixing devices, the PC steel material was fixed by a wedge after it was tensioned (after stress was applied), but slipping always occurred at this time.

The length of this slip varies depending on the material type and wire diameter used, but it can reach as short as 12 mm in 2 strokes, and it also varies depending on the usage conditions such as the storage condition of the materials and equipment used and the 111u work condition. Not constant. However, this slippage causes a large tension loss for the tensed PCM shrine. Since the tensile force of the ring acting on the annular concrete wall is uniformly distributed along the entire circumference, this reduced tension must be reinforced in some way.

Also, it is important to grasp the tensioning device during tensioning work, that is, the PC
The extra length of the IiM material becomes a consumable material, which is economically disadvantageous.

The present invention eliminates the drawbacks of the known methods as described above, and easily and effectively prevents the stress loss caused by slipping when the above-mentioned stress (prestress) is applied to the annular concrete wall. The purpose is to provide the device in a way that does not require the use of a computer. □The present invention is a method for connecting and fixing PC steel members arranged along the circumference of an annular structure by tensioning them at the midpoint. Each end of the PC steel material faces each other, a fixing member is fixed to each of the end portions, and the fixing members are fixed with the PC steel material under tension by drawing the two fixing joints together. This article describes a method and apparatus for applying prestress to an annular structure.

The method and apparatus of the present invention will be explained with the help of figures. 1 is an overall assembly diagram to which the method and apparatus of the present invention are applied, and this figure shows a case where the PCM material 3 is divided into six parts. The greater the number of divisions, the lower the friction loss due to the tension of the PC steel material (as described above). pcflj placed through sheath 11
The material 3 has six cavities 16 which are recesses opened toward the inner surface of the wall 15. This empty vIJ 16 can also be shaped to open toward the outer periphery of the wall. In the cavity 16, the PC steel materials 3 are connected and fixed by a connecting fixing device as a fixing method by drawing fixing devices, which are fixing members fixed to the respective end portions, toward each other.

The structure of the connection fixing device according to the first embodiment of the present invention is shown in FIG. 2 and FIG. . The exterior of the fitting tool 1 is a short tubular shape with a window 6, but the inner circumferential surface is divided into an appropriate number of equal parts, for example 4 to 6, and the equal parts have female threaded parts 7 and groove parts 8 alternately formed. The tubular portion has shallow grooves 12 at both ends thereof.

Two fixing devices 2 made of PCM' material are required for each connection fixing device 1, and the outside engraving in the figure is less than half the length of the connection fixing device, and the outer circumferential surface is similar to the connection fixing device 1. Male screw portions 9 and groove portions 10 are formed alternately to be equally divided into equal parts and engage with the female thread, and the outer diameters of the male screw portion 9 and groove portion 10 are equal to the groove portion 8 and female thread of the connection fixture 1, respectively. It is slightly smaller than the outer diameter of the portion 7 and allows the fixing device 2 to be inserted into the connection fixing device 1. The interior of the fixing device 2 has a conical shape that is open toward the side where it is inserted into the connection fixing device 1 and has a slope that opens to the opposite side. The size of this conical hole is slightly larger than the PC steel material even at its narrowest point, and its maximum outer diameter is slightly smaller than the maximum diameter of the wedge 4 for fixing the PCflll material.

Wedge 4 has PC steel material 3 in the center! It has a cylindrical insertion hole with the same diameter, and the outside has a conical shape with the same slope as the fixing tool 2, and the maximum and minimum diameters of the sloped part of the pattern 4 are larger than those of the conical hole of the fixing tool 2. are each getting larger. Note that the end of the fixing device 2 that is not inserted into the connection fixing device 1 has grooves 13 having the same number and width and depth as the grooves 12 at the end of the connection fixing device 1. A method for connecting and fixing PC steel materials using these connection and fixing devices will be explained with reference to FIGS. 6 and 7. The concrete wall 15 is provided with a recess or cavity 16 of an appropriate size to which work equipment to be described later can be attached. PCFLJ materials 3 protrude from both sides of the hollow cavity 16 through the sheath 11, and these steel materials have a calculated length in a taut state. After a fixing device 2 as shown in FIGS. 2 to 4 is fixed to the tip of each of these PCjN 4=43 by a wedge 4, the fixing device 2 inserts the PC@ material into the connecting fixing device 1. Each terminal is inserted facing each other. Both arms 20A of the tensioning machine 20 made of PC steel.

The tip of 20B has a U-shaped groove with lJ larger than the diameter of the PC steel material 3, and these fH allow it to straddle the PC11 material 3 on both sides, and both arms 20A+ 20B have a The fixing device 2 is attached by placing the shallow protrusions in contact with the grooves 13 of the fixing device 2, and with both side surfaces in contact with the end surfaces of the fixing device 2. After that, depending on the approach distance of the fixing tool from the window 6, etc.
While monitoring the state of tension in the C steel material, the tension machine 20 such as a jack is operated to increase the tension in the PC steel material. PC steel material 3
After reaching a predetermined tension, the connection fixing tool 1 is rotated at a predetermined angle, and the screw projections of the image fixing tools 1 and 2 are engaged to fix the image. Note that the shallow groove 13 of the fixing device 2 prevents the fixing device 2 from rotating or coming off during tensioning work. 12 Continued fixing tool 1
The shallow groove 12 serves as an indicator of the engaged state of the fixing device 2, and can be used together with the shallow groove 13 to fix the fixing device.

Next, regarding the second embodiment of the present invention, FIGS.
This will be explained using Figure 2. The connection fixing tool 1a has a frame shape as shown in the figure, and the portion through which the fixing tool 2a passes has a thickness. The inner diameter of the hole through which the fixing tool 2a passes is larger than the maximum diameter of the male thread on the outer circumferential surface of the fixing tool 2a, and the fixing tool 2a has a conical hole in the axial center and a male thread on the outer circumferential side. The shape of the conical hole of the tool 2a and the shape and structure of the wedge 4 are the same as those of the first embodiment. The difference in structure from the first embodiment is that there is no groove on the entire outer peripheral surface of the fixing tool 2a, and a nut 5 having a female thread that engages with a male thread on this surface is used for fixing.

Figure 12 shows that after reaching a predetermined tension using the same method as above, the nut 5 is screwed onto the male thread of the fixing device 2a, and the
．． 3 shows the work to complete the connection and fixing at the same time.

The tensioning tool and tensioning method are the same as in the first embodiment.

The above embodiments have been described for one PC steel material, but it goes without saying that if necessary, several PC steel materials can be fixed to the PCM material fixing device and connected using the connection fixing device using the above method. be. Furthermore, in this embodiment, fixing is performed by the search method, but the end of the PC steel material can also be fixed to the PC1iliI material fixing device by the crimping method or the rivet head method, and various fixing mechanisms equipped with other conventional fixing mechanisms can also be used. It can also be applied to structures, and although it is fixed to a simple fixing device, a tensioner is not necessarily required if a bolt and nut are used.

After the above-mentioned PC@ material is tensioned, connected and fixed, the tensioning machine is removed and the wall surface is finished by filling the sky height 16 with concrete.

In the present invention, the structure of the fixing device and the tensioning method are as described above, so even if slipping occurs between the PC steel fixing device and the wedge 4 during tensioning, the slippage is completed when the tensioning is finished.
The tension obtained is not reduced but is ensured by the connecting fixture. Furthermore, since the PC steel material can be re-tensioned or back-tensioned freely, effective Sore stress can be obtained up to the limit of the allowable stress level. In addition, since the connection fixing device does not come into contact with the concrete wall and is suspended in a neutral state within the cavity, unlike the fixing device that takes a reaction force within the concrete wall as in conventional construction methods, it is not necessary to use a protruding wall. There is no need to provide one, and there is no need to reinforce the surrounding area.

If devices with the above structures are installed in cavities that are divided and distributed on the circumference of a circular concrete wall and are simultaneously tension-connected, the individual PC steel members placed on the circumference will have a total circumference of 1. It can be considered as a PCfli kidnapping that became a book.
It has the same effect as the evening light that tightens the barrel.

[Brief explanation of the drawing]

Fig. 1 is an overall sectional view of an annular concrete having six cavities to which the method and apparatus of the present invention are applied, and Figs. 2 to 7 show an embodiment of the method and apparatus of the present invention. Fig. 2 is a cross-sectional view of the device before tensioning, Fig. 6 is a cross-sectional view of the device after tension fixing, Fig. 4 is a view taken along arrow M-■ in Fig. 2, and Fig. 5 is a cross-sectional view of the device before tensioning. The V-V arrow view in the figure, FIG. 6 is an explanatory diagram of the connection fixing device of the present invention in one cavity before tensioning, and FIG. 7 is an explanatory diagram of the same after tensioning. . 8 to 12 show the second embodiment of the device of the present invention, and FIG. 8 shows the device after tension fixing in FIG.
vm sectional view, and FIG. 9 is a K − of the device after tension fixing.
10 is a cross-sectional view, FIG. 10 is a view taken along the line xx in FIG. 8, FIG. 11 is a view taken along the line XI-XI in FIG. FIG. 3 is an explanatory cross-sectional view of a state in which the tension connection is fixed. 1.1a... Connection fixing tool, 2, 2a... Fixing tool, 3
...PC steel material, 4...wedge, 5...nut, 6...
... window, 7... acid screw of connection fixing tool 1, 8... groove of connection fixing tool 1, 9... male thread of fixing tool, 10... groove of fixing tool, 11... sheath , 12... Groove at the connection fixing end. Agents: Asamura and Akira 4 people 11 Figure 2 Figure 3 Figure 4. ,,Fig. Fang 5 Fig. O 8 Fig. O 9 Fig. Fang 10 Fig. Fang 11 Fig. O 12

Claims (1)

[Claims] (1) P arranged along the circumference of the annular structure
c In the method of connecting and fixing steel materials by applying tension at their midpoints,
Divided into one or more pieces arranged on the circumference f3 p
c. Each end of the steel material faces each other, fixing members are fixed to both end parts, and the fixing members are pulled together, and the PC
A method for applying prestress to an annular structure, comprising fixing both of the fixing members while keeping the steel material under tension. (2) P arranged along the circumference of the annular structure
A device that connects and fixes the C steel material by tensioning it at the midpoint is used to face each end of the PC steel material, which is divided into one or more pieces arranged on the circumference, and connects the two ends with the search method or the crimping method. , the outer circumference of the fixed member is divided into equal parts using the rivet head method, etc., and a fixing tool made of PC steel is fixed, with external threads and grooves alternately provided.
The inner circumferential surface of the thick inner cylindrical connection fixing device has a female thread and a groove that are equally divided into the outer circumference of the fixing device and engage with the male thread,
and allowing the fixing tool to be inserted into the interior, pushing both of the fixing tools into the connecting fixing tool, pulling the two fixing tools toward each other, and tensioning the two facing PCiill materials; After the PCL material reaches a predetermined tension, the connecting fixing tool is rotated by a predetermined angle to engage the male thread and the female thread, thereby fixing both fixing tools to each other and connecting them once. A device that applies prestress. (8) In the device for applying prestress to an annular structure according to claim 2, the connection fixing device is frame-shaped and p
It has two smooth circular holes on opposite sides through which the fixing tool fixing the CM material can pass, and both the fixing tools of the PCL material are inserted into the circular holes, and after tensioning the PCW4 material, the fixing tool A device for applying prestress to an annular structure, characterized in that both fixing devices are fixedly connected to each other by tightening a nut that matches the external thread on the outer peripheral surface of the device.