JP3380904B2 - Method and apparatus for measuring fixing load of PC steel - 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 measuring a fixing load of a PC steel material during construction of a prestressed concrete structure, and a measuring apparatus therefor.

[0002]

2. Description of the Related Art Prestressed concrete structures (P
In the construction of (C structure), PC steel material (PC steel wire, PC stranded wire, PC steel bar) is used to introduce a prestressing force before or after concrete is placed, as is well known.
Apply tension to. For example, in the case of a post tension method, that is, when a prestressing force is introduced after pouring concrete, a desired tension force is applied to the PC steel material. Then, the end portions thereof are fixed to the pressure bearing plate by using a so-called fixing device (fixing member) of wedge type, screw type or fitting type.

By the way, at the time of fixing the end portion of the PC steel material, it is extremely important for the construction of the PC structure to confirm the fixing tension of the PC steel material, that is, the fixing load of the fixing tool (fixing member). Conventionally, confirm this fixing load,
A so-called fixing load measuring method has been carried out in the following manner.

(1) A jack for applying tension to a PC steel material, generally, a hydraulic center-hole type jack equipped with a pressure gauge is attached to the end of the PC steel material, and the jack is operated to make the PC steel material. Apply tension. At that time, P
A fixing tool (fixing body) is attached to the end of the C steel material, and a pressure plate for receiving the fixing tool is provided. (2) Then, an extra tension is applied to the PC steel material until a gap is formed between the fixing tool (fixing body) and the pressure bearing plate. Specifically, the tension is applied to the extent that a measurement plate formed of a thin steel plate of about 0.3 mm can be inserted. (3) When a gap is formed, the measurement plates are inserted into the gap from different directions to reduce the load on the jack to zero. In other words, it releases without load. Then, the measurement plate inserted into the gap is sandwiched between the fixing tool (fixing body) and the pressure support plate by the tension of the PC steel material. (4) When the sandwiching of the measurement plate is completed, the unloaded jack is reactivated to gradually apply tension to the PC steel material.
Then, the sandwiching force between the fixing plate (fixing body) sandwiching the measurement plate and the pressure support plate is weakened. Therefore, if the tester grasps each end of the measuring plate with his / her fingers and re-operates the jack while pulling the measuring plate and gradually increases the tension to the PC steel material, the measuring plate is fixed at a certain value. It will be possible to pull it out from the sandwiching part. Therefore, at the moment of pulling out, that is, at the moment of pulling out the measurement plate from the sandwiching portion, the value of the pressure gauge attached to the jack was read, and the fixing load was obtained and confirmed from this value. Since the read value has an error, it was measured a plurality of times, the fixing load was calculated from the average value, and the average value of the three consecutive measured values was used as the fixing tension of the tendon, that is, the PC steel material.

Incidentally, FIG. 3 (A) shows the step (3), in which a tension force is applied to the PC steel material 20 via the jack 30 to fix the PC steel material 20 (fixing member) 4.
FIG. 3 is a side view of a main part showing a state in which a measurement plate 60 made of a thin steel plate is sandwiched between 0 and a bearing plate 50 on the fixed side. Reference numeral 30 a is a jack chain ring provided on the head of the jack 30. Although not shown in FIGS. 3A and 3B, the jack 30 is equipped with a pressure gauge. Further, FIG. 3B shows the fixing tool (fixing body) 40.
A shim 70 is interposed between the pressure bearing plate 50 and the bearing plate 50, and the shim 7
FIG. 3 is a side view of an essential part showing a case where a measurement plate 60 is sandwiched between 0 and a fixing tool (fixing body) 40 for measurement.

[0006]

The fixing load of the PC steel material in the conventional PC structure construction has been confirmed and measured in the manner as described above. Therefore, the following problems have been pointed out. (1) Pulling out the measurement plate from the clamped portion depends on the manual work of the measurer. The pulling out is subject to the physical strength of the measurer and varies depending on the individual, resulting in variations in the result. (2) The tester who pulls out the measurement plate from the clamping part and the operator who reads the value of the jack pressure gauge at the moment of pulling out are different persons, and the value of the instrument is based on the signal of the tester who pulled out the measurement plate. Is reading. Therefore, there is a time lag there, and variations in the accuracy of the read value are likely to occur, and the reliability of the result is difficult. (3) The place of measurement is a construction site, which is extremely noisy environmentally, and there is a problem as a highly accurate fixing load measuring means in combination with the reasons (1) and (2) above. It had the drawback of requiring a lot of personnel.

The present invention solves the above problems and drawbacks of the conventional measuring method, has a high accuracy and reliability, and a fixing load measuring method and a measuring apparatus therefor which do not require a large number of personnel for the measuring work. The invention was made for the purpose of providing

[0008]

Therefore, as means for achieving the above object, the present invention applies a tension force to a PC steel material through a jack so that a fixing tool (fixing body) on the PC steel material side and a pressure plate are provided. A gap is formed between them, and a measurement plate made of a thin steel plate is inserted into this gap, and the jack is unloaded and the measurement plate is sandwiched between a fixing tool (fixing body),
Then, the jack is re-activated to gradually increase the tension on the PC steel material, the clamped measurement plate is pulled out from the clamped portion, and the fixing load of the PC steel material is measured based on the jack load at the moment of pulling out. As a way to do, first,
I configured it as follows:

The end portion of the measuring plate sandwiched between the fixing member (fixing body) made of PC steel and the pressure bearing plate is held by the pulling-out means of the measuring plate which stores a constant pulling force. Then, the fixing load of the PC steel material can be confirmed in real time through the display means based on the pulling-out operation signal of the measuring plate by the pulling-out means.

Next, an apparatus for carrying out the above-mentioned measuring method was constructed as follows. First, a pulling-out device for a measuring plate is configured by a holding means for holding the end portion of the measuring plate and a storing means for storing the pulling-out force of the measuring plate.

Then, a transmitting means for transmitting a pulling-out operation signal when pulling out the measuring plate is attached to the pulling-out device. Further, display means for displaying the fixing load of the PC steel material based on the operation signal from the transmitting means is connected to the pulling device, and the pulling device, the transmitting means for transmitting the operating signal of the pulling device, and the fixing load are displayed. Three
It was a fixing load measuring device for PC steel consisting of two main components.

The grasping means for grasping the end portion of the measuring plate is constituted by a clamp means composed of a bolt and nut. The energy accumulating means for accumulating the pulling force of the measuring plate is configured as follows by combining the frame member, the guide rod, the operating rod, and the spring member.

First, the frame member was constructed as a portal frame. The guide rod has a rod-like body, a tip end portion is inserted through an insertion hole provided in the top end portion of the frame member, and a stopper nut for preventing slip-off is screwed into the base end portion.

The operating rod is composed of an elongated strip-shaped plate material, and the base end portion thereof is bent into an L-shape to form a support portion, and the guide rod of the guide rod is provided through a guide hole provided in the support portion. The guide rod was inserted so as to be movable in the axial direction from the tip end side and held by the guide rod.

Next, as the spring member, a coil spring is used, and the guide rod is covered from the tip end side, and a receiving plate is attached to the tip end of the guide rod. The receiving plate and the base end of the operating rod are attached. It was interposed between the L-shaped receiving and supporting part of the part.

Further, the clamp for gripping the end portion of the measuring plate is attached to the tip end portion of the operating rod in the energy storing means for storing the pulling force of the measuring plate.

Next, the transmitting means for transmitting the signal for actuating the withdrawal of the measuring plate by the withdrawal device is turned on with the movement of the operating rod in the withdrawal device in the axial direction.
It is configured with a switch that is turned off.

The display means for displaying the fixing load of the PC steel material based on the operation signal is a jack pressure gauge for applying a tension force to the PC steel material to a display device having a numerical display and a blinking type indicator light via the switch. It is characterized in that it is configured to be connected.

[0019]

The measuring method and apparatus for measuring the fixing load of the PC steel material according to the present invention is constructed as described above. Therefore, the measuring plate should be sandwiched in advance between the fixing tool (fixing body) and the pressure bearing plate. deep. Then, the end portion of the measuring plate is clamped by the grip portion formed of a bolt and nut attached to the tip end portion of the operating rod in the pulling device. At that time, the operating rod is pulled out in the axial direction against the spring member mounted on the guide rod. As a result, the spring member interposed between the tip end portion of the guide rod and the base end portion of the operating rod is compressed, and the actuating rod itself has a force to restore the actuating rod toward the base end portion. Will be stored up. That is, a constant pulling force for pulling the measuring plate out of the sandwiched portion is stored through the operating rod.

Therefore, when the jack is operated to gradually apply tension to the PC steel material, the clamping force of the clamping portion formed by the fixing tool (fixing body) and the pressure support plate is weakened. When the clamping force becomes less than the withdrawal force stored in the operating rod of the extracting device, the measuring plate is automatically withdrawn from the clamping part. That is, the operating rod is restored to its original position.

Since the operating rod is equipped with a transmitting means for transmitting an operating signal at the time of its operation, that is, a switch for ON-OFF operation, this switch is turned ON. The switch is ON because it is connected to a display device that has a numerical display and a blinking type indicator light via a pressure gauge of a jack that applies tension to the PC steel material.
If it operates, the fixing load of the PC steel material at that moment will be displayed instantaneously.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in the drawings. In the following explanation,
It was used to explain the conventional measuring method, that is, FIG.
Parts that are common to the part numbers given in (B) and (B) will be described using the same reference numerals. First, FIG. 1 is a side view of an essential part showing a state in which a measuring plate 60 is sandwiched between a fixing tool (fixing body) 40 and a pressure support plate 50. That is, it is a side view of the main part showing a state in which the pulling-out device holds the end portion of the measurement plate 60 in a state in which a force for pulling out the end portion of the held measurement plate 60 from the holding portion is stored. Also, FIG.
[Fig. 4] is a side view of a main part showing a state where the measurement plate 60 is pulled out.

As described above, the pulling-out device includes a clamp 1 composed of a bolt and a nut for gripping the end of the measuring plate 60, a frame member 2, a guide rod 3, an operating rod 4, and the like.
It is configured with the spring member 5. The frame member 2 is constituted by a gate-shaped frame member as shown in the drawing, and the left leg end side is attached between the jack 30 side and the pressure support plate 50. In the figure, it is attached horizontally. Then, an insertion hole 2b for a guide rod 3 described later is formed in the right end 2a. The guide rod 3 is retained in the gate-shaped frame member 2 by screwing a stopper nut 3c that prevents the guide rod 3 from slipping off, and inserting the tip portion 3a (left side in the drawing) from the insertion hole 2b of the frame member 2. Assembled so that

The operating rod 4 is composed of a rod-shaped rod member having an elongated strip shape, and its base end portion (right side in the drawing) is bent into an L-shape to form a support portion 4a. Has a guide hole 4b. Then, the guide rod 3 is inserted into the guide hole 4b.
The distal end portion 3a side was inserted, and the operating rod 4 itself was movably inserted in the axial direction, that is, the horizontal direction. That is, the operating rod 4 is housed in the gate-shaped frame member 2 via the guide rod 3.

Next, as the spring member 5, a coil spring is used as shown in the drawing. The coil spring is mounted on the tip 3a of the guide rod 3 from the left side in the figure, and the receiving plate 3d is attached to the tip 3a of the guide rod 3. Was attached and was interposed between the receiving plate 3d and the receiving and supporting portion 4a of the operating rod 4. The clamp 1 composed of the bolt and nut is attached to the tip 4c of the operating rod 4, that is, the left end of the operating rod 4 in the figure.

That is, when the side of the clamp 1 attached to the tip 4c (left end in the figure) of the operating rod 4 is pulled out to the left along the guide rod 3, the spring member 5 is compressed and the operating rod 4 itself. It is configured so that a constant restoring force is accumulated. That is, the force for pulling out the measurement plate 60 from the sandwiching portion in the right direction is automatically stored.

Next, the jack 30 is re-activated on the PC steel material 20 to gradually apply a tension force, and the operation signal at the moment when the measuring plate 60 is pulled out from the sandwiching portion by utilizing the pulling force accumulated in the pulling device. As conceptually shown in FIG. 1, the switch 6 for transmitting the signal is installed near the rear end (right side in the drawing) of the operating rod 4 which constitutes the pulling device. Specifically, a limit switch type switch 6 that is turned on and off when the operating rod 4 is operated in the front-rear horizontal direction is installed in association with the operating rod 4.

FIG. 2 shows that the measurement plate 60 is pulled out, and as a result,
The state where the receiving and supporting portion 4a of the operating rod 4 has moved rightward to the top end portion 2a of the frame member 2 and has been turned on by the moving operation is shown.

Based on the operation signal of the drawing device,
The display means for displaying the fixing load of the PC steel material 20, that is, the display device 7, is a display device 7 having a display 8 and a blinking type indicator lamp 9 in which digital numerical value display means is incorporated as shown in FIGS. Configured with. And
The pressure gauge 10 of the jack 30 was connected to the display device 7 via the switch 6. Note that FIG. 2 shows a state in which the measuring plate 60 is pulled out from the sandwiched portion and the fixing load of the PC steel material 20 at the moment of pulling out is displayed on the display device 7 as described above. In FIGS. 1 and 2, reference numeral 11 is a pedestal attached to the left end of the frame member 2 for setting the extraction device at the measurement position.

[0030]

Since the present invention is configured as described above through the embodiments, the following effects are exhibited as compared with the conventional measuring method or apparatus. (1) The measured value does not vary from person to person. That is, since the measurement plate is pulled out by the stored constant pulling force, there is no variation in the measured value, and the fixing load can be confirmed with high accuracy. (2) A display device that instantaneously captures the pulling-out operation of the measuring plate via the transmitting means, and has a digital display of the fixing load of the PC steel material based on the jack pressure at the time of capture and a blinking type indicator light. Since the measurer is notified via the above, it is possible to confirm the fixing load accurately without any variation together with the action and effect of (1). (3) The human-dependent part in the measurement work is only the part where the measuring plate is inserted into the predetermined gap and clamped, and the end of the clamped measuring plate is clamped by the pulling device.
Therefore, the measurement work can be performed by an extremely simple work and does not require a lot of manpower as in the past. (4) In particular, since it is not a method in which an operator reads a pressure gauge that operates instantaneously and obtains a result based on the read value as in the conventional case, no reading error occurs,
Combined with the effect of (3), the stability, speediness and accuracy of the measurement work are significantly improved.

[Brief description of drawings]

FIG. 1 is a side view showing a main part of an apparatus for carrying out a measuring method according to the present invention, in which a measuring plate is sandwiched between a fixing tool (fixing body) and a pressure bearing plate, and an end portion of the measuring plate is The state which was made to grasp by the clamp which comprises a pull-out apparatus is shown.

FIG. 2 is a side view showing a main part of the apparatus showing a state where the measurement plate is pulled out from the sandwiching part.

FIG. 3 shows a main part of an apparatus for explaining a conventional measuring method, and (A) is a side view of a main part in which a measurement plate is sandwiched between a fixing tool (fixing body) and a pressure plate. In the figure, (B) is a side view of a main part in which a measurement plate is sandwiched with a shim interposed between a pressure bearing plate and a fixing tool (fixing body).

[Explanation of symbols]

20 ... PC steel (PC wire, PC stranded wire, PC steel rod) 30 ... Jack 30a ... jack chainring 40: Fixing tool (fixing body) 50 ... Bearing plate 60 ... Measuring plate 70 ... Sim 1 ... Clamp (bolt nut type) 2 ... Frame member (gate frame) 2a ... the top end 2b ... Insertion hole 3 ... Guide rod 3a ... Tip 3b ... Base end 3c ... stop nut 3d ...... Retaining plate 4 ... Operating rod 4a ... Receiving branch 4b ... Guide hole 4c ... Tip 5: Spring member (roll spring) 6 ... Switch (operation signal transmission means) 7 ... Display device 8: Digital display 9: Flashing type indicator light 10 ... Pressure gauge (jack 30) 11 ... Pedestal

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-118231 (JP, A) JP 60-128320 (JP, A) JP 56-85019 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01L 5/00 E04G 21/12 104

Claims (4)

(57) [Claims] 1. A tension force is applied to a PC steel material through a jack to form a gap between a fixing tool on the PC steel material side and a pressure plate or a shim, and a measurement plate made of a thin steel plate is inserted into the gap. , The measurement plate is clamped between the fixing device and the pressure support plate with the jack unloaded, and the clamp is clamped while reactivating the jack to gradually increase the tension on the PC steel material. Pull out from the clamp part,
A method of measuring the fixing load of the PC steel material on the basis of the jack load at the moment of pulling out, in which a fixed pulling force is accumulated at the end of the measuring plate sandwiched between the fixing tool and the pressure support plate. Grasped by the drawn-out means for pulling out the measuring plate, and based on the pull-out operation signal of the measuring board by this drawn-out means,
A fixing load measuring method for PC steel, comprising confirming the fixing load of PC steel through a display means. 2. A measuring plate withdrawing device comprising a holding means for holding an end portion of the measuring plate and an energy storing means for accumulating withdrawing force of the measuring plate, and a pulling-out operation of the measuring plate by the withdrawing device. Withdrawal actuation signal transmission means,
A fixing load measuring device for a PC steel material, comprising: a display means for displaying the fixing load of the PC steel material based on the operation signal from the transmitting means. 3. The gripping means for gripping the end portion of the measuring plate is a clamp made of a bolt and nut, and the accumulating means for accumulating the pulling force of the measuring plate includes a frame member, a guide rod, and an operating rod. The frame member has a gate shape, and the guide rod has a distal end portion inserted through an insertion hole provided at a top end portion of the frame member, and a stopper for preventing the guide rod from slipping off at a base end portion side. The actuating rod is formed by bending a base end portion into an L-shape to form a receiving support portion, and a tip end of the guide rod is provided through a guide hole provided in the receiving support portion. It is movably inserted in the axial direction from the part side, and is held by a guide rod.The spring member is made of a coil spring, and the guide rod is externally fitted from the tip end side to the tip end of the guide rod. Attaches a catch plate, and this catch plate and L of the base end part in the said operating rod. Wherein the clamp for holding the end of the measuring plate is a device for pulling out the measuring plate attached to the tip of the operating rod. Item 2. A fixing load measuring device for PC steel according to Item 2. 4. A transmitting means for transmitting an operation signal at the time of the pulling-out operation of the measuring plate by the pulling-out device is turned on along with the movement of the operating rod in the pulling-out device in the axial direction.
The display means for displaying the fixing load of the PC steel material on the basis of the operation signal is composed of a switch that is turned off, and a numerical value display and a blinking type display in which a pressure gauge of a jack for applying tension to the PC steel material is connected through the switch. The fixing load measuring device for PC steel according to claim 2 or 3, which is a display device including a lamp.