JP3603277B2 - Tension measuring device and tension measuring method using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tension measurement for measuring a tension at a fixing portion of a tension member to a concrete member (hereinafter, referred to as a "tension of a tension member") in a prestressed concrete (hereinafter, referred to as "PC") structure. Equipment related.
[0002]
[Prior art]
In the construction of PC structures, unbonded post-tension methods (VSL method, BBRV method, Freycinet method) are one of the typical methods for applying a prestress by tensioning a tendon such as PC steel and fixing it to a concrete member. , KTB method, Dywidag method, etc.). In the above-mentioned construction method, after completion of the tensioning work of the tendon material, a change in the tension force of the tendon material may be examined to grasp the state of the prestressing force in order to periodically check the structural soundness.
[0003]
Conventionally, as shown in FIG. 5, at the end of a concrete member 91, a fixing member 94 is fixed at an end of a concrete member 91 to a supporting plate 93 via an anchor head 92. For the measurement of the lift-off load), the following lift-off test method was generally used due to factors such as workability.
[0004]
(1) A jack chair 97 is provided around the anchor head 92, and a hydraulic jack 95 for separating the anchor head 92 from the supporting plate 93 is attached by a chain block (not shown) or the like.
(2) By actuating the hydraulic jack 95 to apply tension to the tension member 94, the anchor head 92 is separated from the support plate 93. The fact that the anchor head 92 has been separated from the support plate 93 is determined by two thin left and right measurement plates 96 (a stainless steel plate having a thickness of about 0.3 mm) interposed symmetrically in advance between the anchor head 92 and the support plate 93. It is determined by detecting that the thin copper plate has been pulled out, and the pressure acting on the hydraulic jack 95 at that time is measured by a hydraulic gauge, a manometer, or the like.
In this way, by measuring the fixing force acting on the anchor head 92, the tension of the tension member 94, which is the reaction force, is measured.
[0005]
[Problems to be solved by the invention]
However, in the lift-off test method, two measuring plates 96, which are sandwiched between the support plate 93 and the anchor head 92 at the time of measuring the tension, are moved by the two operators on both sides at all times during the measurement. , And it required a lot of labor and effort. In addition, it is necessary to accurately perform a force operation of the hydraulic jack 95 so that the hydraulic pressure at the moment when the measuring plate 96 is pulled out can be accurately read. However, the operation is very difficult and must be performed by a skilled operator. I had to.
Furthermore, in order to sandwich the measuring plate 96 between the support plate 93 and the anchor head 92 before measuring the tension, the anchor head 92 must be separated from the support plate 93, so that it is the same as when measuring the tension. It took a lot of effort.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a tension measuring apparatus and a tension measuring apparatus capable of easily measuring the tension of a tension member without using a measuring plate . It is an object of the present invention to provide a tension measuring method .
[0008]
[Means for Solving the Problems]
The tension measuring device of the present invention is a device used to measure a tension acting on an existing tendon material fixed to a bearing member via a fixing member at an end of a concrete member, A hydraulic operating portion interposed in advance between the fixing member and the supporting member, a hydraulic supply unit to the hydraulic operating unit, and a change in an amount of oil supplied from the hydraulic supply unit to the hydraulic operating unit. An oil amount detecting means for measuring, and a pressure measuring means for measuring a hydraulic pressure acting on the hydraulic working section, wherein the hydraulic working section is an insertion section for the tendon, and the hydraulic supply section. It is composed of a main body having a hydraulic chamber to be connected, and a ram member displaced in a direction away from the main body by the hydraulic pressure acting on the hydraulic chamber. When the measurement of the tension is not performed, With the end surface on the fixing member side Serial is characterized in state der Rukoto which the end face of the Bearing member side are in close contact of the ram member.
[0009]
Therefore, according to the tension measuring device of the present invention, a change in the amount of oil supplied from the hydraulic pressure supply unit is detected by the oil amount detection unit, and acts on the hydraulic separation unit or the hydraulic working unit that balances the tension of the tendon. Since the hydraulic pressure can be accurately measured, the tension of the tendon can be easily measured without using a measuring plate.
The ram member includes a column portion inserted into the hydraulic chamber, and a pressing portion displaced in a direction away from the main body together with the column portion by the hydraulic pressure acting on the hydraulic chamber. When the tension is not measured, it is preferable that the end surface of the main body on the fixing member side and the end surface of the pressing portion on the supporting member side are in close contact with each other.
[0010]
Further, in the tension measuring device, before Kiyu amount detecting means detects the rod member is movable inside the cylinder and the cylinder in the axial direction, a relative displacement amount between said rod member and said cylinder relative And a displacement detector.
[0011]
Therefore, according to the tension measuring device of the present invention, the change in the amount of oil supplied from the hydraulic pressure supply means is detected by the relative displacement amount detection unit as the relative displacement between the cylinder and the rod member, thereby providing a tension member. It is possible to accurately measure the hydraulic pressure acting on the hydraulic separating means or the hydraulic operating portion, which balances with the tension of the hydraulic pressure.
Further, according to a tension measuring method of the present invention, a tension acting on an existing tension member fixed to a supporting member via a fixing member by using the tension measuring device according to claim 1 or 2. A method for measuring a force, wherein a first step of supplying pressurized oil to the hydraulic working section by the hydraulic supply section and a change in an amount of oil supplied to the hydraulic working section are measured by the oil amount detecting section. A second step, a third step of measuring the oil pressure acting on the hydraulic working portion by the oil pressure detecting means, and detecting an initial displacement of the tendon member based on a change in the oil amount measured by the oil amount detecting means. And a fourth step of obtaining a tension acting on the tension member from the hydraulic pressure at the time when the initial displacement is detected.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
In the description of each embodiment, the same components will be denoted by the same reference symbols, without redundant description.
[0013]
[First Embodiment]
○ Tension measuring device The tension measuring device S according to the present embodiment is configured such that the hydraulic load cell 10 constituting the device is always interposed between the support plate B and the anchor head A, so that the tension measuring device S It is an excellent device that can measure the tension K.
[0014]
As shown in FIGS. 1 and 2, the tension measuring device S (first embodiment) of the present invention transmits a hydraulic load cell 10 (hydraulic operating section) and an oil cell 13 (hydraulic chamber) of the hydraulic load cell 10. A manually operated hydraulic pump 20 (hydraulic supply means) for supplying hydraulic oil and discharging hydraulic oil from the oil cell 13, and a hydraulic measuring device 30 (for measuring hydraulic pressure acting on the hydraulic load cell 10) The main components are a pressure measuring unit) and an oil amount detecting device 40 (oil amount detecting unit) for measuring a change in the amount of oil supplied from the hydraulic pump 20 to the hydraulic load cell 10.
[0015]
As shown in FIG. 2, the main body 11 of the hydraulic load cell 10 has a cylindrical shape, and has an insertion part 12 of a columnar tension material K (PC steel strand or the like) in the center. The main body 11 is formed in a so-called half-shape, which is cut in a direction perpendicular to the axial direction of the insertion portion 12 and passing through the diameter of a hollow circle formed on the end face of the main body 11 and divided into two. (Hereinafter, one half of the main body having a half-split shape is referred to as a “half-cylindrical main body”). These two semi-cylindrical body portions 11A and 11B have the same outer shape and are integrated by a connecting member (not shown).
[0016]
In addition, a plurality of cylinder-shaped (six in the present embodiment) oil cells 13 which are particularly excellent in workability are formed in the end surface 11a on one end side of each of the semi-cylindrical main bodies 11A and 11B. Have been. The plurality of oil cells 13 are in communication with each other. One of the oil cells 13A is connected to the hydraulic pump 20 via the oil passage 14 formed in the main body 11 and the hydraulic lines 21A and 21B. I have.
In addition, a coupler 24 is attached to an entrance / exit of the oil passage 14 of the main body 11.
[0017]
The ram member 15 is also formed from two half portions 15A and 15B having the same shape. The halves 15A and 15B of the ram member 15 have a half-shaped pressing portion 15a having the same shape as the end surface 11a of the semi-cylindrical main bodies 11A and 11B, and an O-ring 16 in each of the oil cells 13. And a plurality of pillar portions 15b which are inserted and formed in a shape movable in the axial direction. This allows the ram member 15 to move in a direction away from the main body 11 by being guided to the oil cell 13.
Reference numeral 17 denotes a spring provided in each oil cell 13 for urging the ram member 15 in a direction approaching the main body 11.
[0018]
Further, a coupler 23 that engages with the coupler 24 of the main body 11 is attached to the distal end side of the hydraulic pipeline 21B, and the other end side is connected to the cylinder 42 of the oil amount detection device 40. The cylinder 42 is connected to a discharge part of the hydraulic pump 20 by a hydraulic line 21A. The hydraulic line 21B is detachable by couplers 23 and 24, and is provided separately when the oil is guided during the tension measurement, and is provided separately from the hydraulic pump 20, the hydraulic pressure measuring device 30, and the oil pressure measuring device 30. The amount detection device 40 can be attached.
[0019]
The hydraulic load cell 10 is always held between the support plate B and the anchor head A. Therefore, in normal times when the tension is not measured, no oil pressure is generated in the oil cell 13, and the main body 11 and the ram member 15 are in close contact with each other, and serve as a shim.
[0020]
The oil amount detection device 40 includes a cylinder 42, a rod 43 (rod member), and a displacement meter 44 (relative displacement amount detection unit).
The cylinder 42 includes a cylinder chamber (not shown) connected to the hydraulic pipelines 21A and 21B, and a rod 43 that can move axially inside the cylinder chamber in accordance with the amount of oil in the cylinder chamber. Is provided. The displacement meter 44 is a device for detecting the relative displacement between the cylinder 42 and the rod 43.
[0021]
The oil pressure measuring device 30 is detachably connected to the oil pressure pipeline 21B, and the oil pressure and relative displacement measured by the oil pressure measuring device 30 and the oil amount detecting device 40 are collected by a small computer. The information is recorded in the device 22. The relationship between the oil pressure (P) and the relative displacement (d) (oil pressure / relative displacement curve) is displayed on a display (not shown) of the small computer (see FIG. 3). .
[0022]
The method for measuring the tension is described below with reference to FIG. 1. In the end portion of the concrete member C, which is inserted into the sheath D and is supported by the support plate B (support pressure) via the anchor head A (fixing member). A method for measuring the tension acting on the existing tendon K fixed to the member will be described.
Note that the hydraulic load cell 10 in the tension measuring device S is previously interposed between the support plate B and the anchor head A, and all other devices are in a state of being installed.
[0023]
The work of measuring the tension is performed by displacing the ram member 15 in the axial direction (in a direction away from the main body 11) by feeding oil to the oil cell 13 of the hydraulic load cell 10, and when the ram member 15 is initially displaced, The operation of obtaining the tension acting on the tendon K by measuring the oil pressure acting on the ram member 15 with the hydraulic pressure measuring device 30 is performed.
[0024]
Oil is guided to the oil cell 13 by the hydraulic pump 20, and the ram member 15 is gradually pressurized. When the pressurization proceeds and the pressing force of the ram member 15 exceeds the fixing force acting on the anchor head A, the ram member 15 is displaced in the direction of the anchor head A. By detecting the initial displacement of the ram member 15 and measuring the oil pressure acting on the ram member 15 by the hydraulic pressure measuring device 30 at the time when the predetermined displacement amount is detected, the data recording device 22 Record. This makes it possible to measure the fixing force acting on the anchor head A and measure the tension of the tendon K, which is the reaction force.
[0025]
The initial displacement of the ram member 15 is detected by the following method.
That is, when the ram member 15 is displaced, the volume of the oil cell 13 in the hydraulic load cell 10 increases, so that the amount of oil flowing into the oil cell 13 rapidly increases. At this time, the oil flowing from the hydraulic pump 20 into the oil cell 13 passes through the cylinder chamber of the cylinder 42 in the oil amount detection device 40.
Here, when the amount of oil in the cylinder chamber increases, the rod 43 in the cylinder chamber extends in a direction away from the cylinder 42 (to the left in FIG. 1), and the relative displacement between the cylinder 42 and the rod 43 increases rapidly. I do. The point at which the relative displacement amount rapidly increases becomes apparent by detecting a point (point A) at which the slope of the hydraulic pressure / relative displacement amount curve changes and becomes gentle as shown in FIG. By detecting the oil pressure at point A, the value of the pressure acting in the oil cell 13 that balances the tension of the tendon K can be accurately measured from the amount of oil flowing into the oil cell 13.
[0026]
The detection of the point a may be performed while the measurer visually observes the display, or may be performed by a predetermined program stored in advance in the data collection device. The analysis may be performed by ex post analysis of the amount of data.
[0027]
Once installed, the hydraulic load cell 10 constituting the tension measuring device S of the present embodiment can be always installed once, and can be installed at all times. The detection device 40 can be appropriately attached and detached. Therefore, the hydraulic pump 20, the hydraulic measuring device 30, and the oil amount detecting device 40 are removed after the measurement of the tension, and the measurement can be performed by attaching only the hydraulic pump 20 and the hydraulic measuring device 30 at the next and subsequent measurements. The measuring operation can be performed very easily.
[0028]
As described above, according to the tension measuring device S, it is not necessary to provide a measuring plate when measuring the tension of the tendon K, and the hydraulic pressure when the initial displacement of the ram member 15 is generated by the hydraulic pressure measuring device 30 is reduced. Can be measured. This eliminates the need for an operator for pulling out the measuring plate, which is conventionally required, and eliminates the complicated work required for installing the measuring plate. be able to.
[0029]
[Second embodiment]
The tension measuring device S '(second embodiment) of the present invention is a device in which a center hole jack 10' (hydraulic separating means) is provided at the end of the anchor head A, and the anchor head is directly attached to the support plate B. This is a device for measuring the tension of the tendon K when A is fixed.
[0030]
○ Tension measuring device As shown in FIG. 4, the tension measuring device S ′ of the present embodiment supplies pressure oil to a center hole jack 10 ′ and a hydraulic chamber (not shown) of the center hole jack 10 ′. In addition, an electric hydraulic pump 20 ′ (hydraulic supply means) for discharging pressurized oil from the hydraulic chamber and a hydraulic measuring device 30 (pressure) for measuring the hydraulic pressure acting on the center hole jack 10 ′. The main part includes an oil amount detecting device 40 (oil amount detecting means) for measuring a change in the amount of oil supplied from the hydraulic pump 20 to the center hole jack 10 '.
[0031]
An existing device can be used for the center hole jack 10 ′, and the center hole jack 10 ′ depends on the main body 11 ′, the hydraulic chamber formed inside the main body 11 ′, and the amount of oil introduced into the hydraulic chamber. And a ram member 15 'which can move in the axial direction in the inside thereof.
In the center of the main body 11 ', an insertion hole (not shown) for inserting a plurality of tendons K is formed, and each tendon K is fixed at a position behind the ram member 15'. You can do it.
The hydraulic pump 20 'is connected to hydraulic lines 21A' and 21B '(the reference numeral 21C' is also a hydraulic line) via a hydraulic pressure measuring device 30 and an oil amount detecting device 40, which are the same devices as in the first embodiment. It is connected to the hydraulic chamber of the center hole jack 10 '.
[0032]
The method of measuring the tension acting on the existing tendon K will be described below with reference to FIG.
The center hole jack 10 'in the tension measuring device S' is previously attached to the end of the anchor head A 'via a jack chair J, and the tendon K is fixed to the anchor head A by a wedge 19. ing. All other devices are also installed.
[0033]
The hydraulic pump 20 ′ guides oil to a hydraulic chamber (not shown) of the center hole jack 10 ′ to apply tension to the tendon K, thereby separating the anchor head A from the support plate B. At this time, since the ram member 15 'is displaced in a direction away from the main body 11', the volume of the hydraulic chamber of the main body 11 'increases, and the amount of oil flowing into the hydraulic chamber rapidly increases. become. At this time, according to the same principle as in the first embodiment, the hydraulic pressure acting on the hydraulic chamber can be measured by the hydraulic pressure measuring device 30 through the increased amount of oil flowing into the hydraulic chamber from the hydraulic pump 20 '.
[0034]
Therefore, according to the tension measuring device S 'of the second embodiment, an operator for pulling out the measuring plate, which is conventionally required, is not required, and a complicated operation required for installing the measuring plate is not required. Therefore, the operation of measuring the tension can be performed very efficiently.
[0035]
As described above, an example of a preferred embodiment of the present invention has been described. However, the present invention is not limited to the embodiment, and a design change can be appropriately made without departing from the gist of the present invention.
Note that a pressure amplifier or the like may be provided between the hydraulic pump and the hydraulic operating section or the hydraulic separating means.
[0036]
【The invention's effect】
According to the present invention, at the time of measuring the tension of the tendon, there is no need to provide a measuring plate, so that an operator for pulling out the measuring plate is not required, and a complicated operation required for installing the measuring plate is unnecessary. Therefore, the operation of measuring the tension can be performed very efficiently.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a tension measuring device (first embodiment) of the present invention.
FIGS. 2A and 2B are diagrams showing a hydraulic load cell, wherein FIG. 2A is a cross-sectional view of a main body, and FIG.
FIG. 3 is a graph showing a hydraulic pressure / relative displacement amount curve (a curve showing the relationship between the hydraulic pressure and the relative displacement amount) (the vertical axis represents the hydraulic pressure (P), and the horizontal axis represents the relative displacement amount (d)).
FIG. 4 is a side sectional view showing a tension measuring device (second embodiment) of the present invention.
FIGS. 5A and 5B are diagrams showing a conventional tension measuring device, wherein FIG. 5A is a side sectional view, and FIG.
[Explanation of symbols]
A anchor head (fixing member)
B Support plate (support member)
C Concrete member K Tendon S, S 'Tensile measuring device 10 Hydraulic load cell (hydraulic working part)
10 'hydraulic jack (hydraulic separation means)
11, 11 'body 12 insertion section 13 oil cell (hydraulic chamber)
15, 15 'Ram member 20, 20' Hydraulic pump (hydraulic supply means)
Reference Signs List 30 oil pressure measuring device 40 oil amount detecting device 42 cylinder 43 rod (rod member)
44 Displacement meter (relative displacement amount detection unit)

Claims (4)

At the end of the concrete member is a device used to measure the tension acting on the existing tendon material fixed to the bearing member via the fixing member,
A hydraulic working unit previously provided between the fixing member and the supporting member,
Means for supplying hydraulic pressure to the hydraulic working section;
Oil amount detection means for measuring a change in the amount of oil supplied from the oil pressure supply means to the hydraulic action unit,
Pressure measuring means for measuring the hydraulic pressure acting on the hydraulic working portion ,
A main body having a hydraulic chamber connected to the tension member insertion portion and the hydraulic supply means; and a ram displaced in a direction away from the main body by the hydraulic pressure acting on the hydraulic chamber. And components,
When not performing measurement of tension is tension measuring device according to claim state der Rukoto which the end face of the Bearing member side are in close contact of the ram member and the end surface of the fixing member side of the main body portion. The ram member includes a column portion inserted into the hydraulic chamber, and a pressing portion that is displaced in a direction away from the main body together with the column portion by the hydraulic pressure acting on the hydraulic chamber,
2. The tension according to claim 1, wherein when the tension is not measured, the end surface of the main body on the fixing member side and the end surface of the pressing portion on the supporting member side are in close contact with each other. measuring device. Before Kiyu amount detecting means includes a rod member is movable inside the cylinder and the cylinder in the axial direction, and the relative displacement amount detecting unit for detecting a relative displacement between the rod member and the cylinder, the The tension measuring device according to claim 1 or 2, wherein A method for measuring a tension acting on an existing tension member fixed to a supporting member via a fixing member, using the tension measuring device according to any one of claims 1 to 3. So,
A first step of supplying pressurized oil to the hydraulic working section by the hydraulic supply means;
A second step of measuring a change in an amount of oil supplied to the hydraulic working portion by the oil amount detecting means;
A third step of measuring a hydraulic pressure acting on the hydraulic working section by the hydraulic pressure detecting means;
A fourth step of detecting an initial displacement of the tension member based on a change in the oil amount measured by the oil amount detection means, and obtaining a tension acting on the tension member from the oil pressure at the time of detecting the initial displacement. And a method for measuring tension.

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