JP2014059157A - Tension force estimating method for pc cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly or easily estimate the tension force of a PC cable or cables without attaching an additional device or consequently increasing the dimensions of the members of a PC structure extremely.SOLUTION: A PC cable or cables 1, made tight together, are cut or separated at an arbitrary place. The cut or separated parts of the PC cable or cables 1 are connected by a connection securing device 2. A strain gauge 5 is attached to the body portion of the connection securing device 2. With tension force applied to the PC cable or cables 1, the tension force of the PC cable or cables 1 is estimated on the basis of the strain value of the body portion of the connection securing device 2, the value being detected by the strain gauge 5.

Description

  The present invention relates to a method for estimating the tension of a PC cable.

In patent document 1, the stress provided with the hollow member which inserts a reinforcing bar, the secondary coil wound around the inner periphery, the primary coil wound around the outer periphery, and the thermometer which detects the temperature of a reinforcing bar There is known a method in which a sensor is used to measure a current stress at an arbitrary position of a reinforcing bar of a reinforced concrete structure in a non-contact manner by a magnetostriction method. According to this method, in order to install the stress sensor, the coil is simply wound around the inside and outside of the hollow member inserted into the reinforcing bar, so that the strength of the reinforcing bar is not weakened.
Such a method using a stress sensor is used when measuring the existing stress of a PC steel strand (PC cable) as a tension material for a prestressed concrete structure (PC structure) that is high in strength and does not crack. ing.

In Patent Document 2, a method is proposed in which a member to be measured is inserted between a fixing member at a tension end and a fixing plate, and a compressive force acting on the member to be measured is measured by a magnetostriction method or the like.
There is also a method of inserting a measuring tool such as a load cell between the fixing member at the tension end and the fixing plate.

Japanese Patent No. 3942463 (Japanese Patent Laid-Open No. 2003-270059) Japanese Patent No. 4316283 (Japanese Patent Laid-Open No. 2004-316093)

  However, in the case of the stress sensor disclosed in Patent Document 1, since the coil is wound from above the sheath and the outer diameter is about three times the sheath diameter, there is a possibility that it does not fit within the member dimensions of the PC structure. Moreover, since special equipment is used, it is very expensive.

  In addition, the method of inserting a member to be measured and a load cell as in Patent Document 2 between the fixing member and the fixing plate at the tension end cannot be measured outside the fixing member. That is, it is not possible to directly measure stress at an arbitrary portion of the cable, particularly at a design cross-sectional position important for a PC structure.

  It is an object of the present invention to make it possible to directly and easily estimate the tension of a PC cable without attaching a new device and therefore greatly increasing the size of a PC structure member. .

In order to solve the above problems, the invention described in claim 1
Cut or separate a PC cable formed from one or more simultaneously tensioned at any position, connect the PC cable cutting / separating part with a connecting fixing tool, and connect the strain gauge to the main body of the connecting fixing tool. Paste
A PC cable tension estimation method for estimating a tension of the PC cable based on a strain value of the main part of the connection fixing tool detected by the strain gauge in a state where tension is applied to the PC cable. To do.

The invention described in claim 2
An arbitrary part of the sheath into which a plurality of PC cables that are simultaneously tensioned can be opened and closed in advance, and a part or all of the PC cable is cut and separated at an opening part where the part of the sheath is opened. , Reconnect the PC cable cutting / separating parts one by one or all at once with a connection fixing tool, and attach a strain gauge to the cylindrical main body of the connection fixing tool,
A PC cable tension estimation method for estimating a tension of the PC cable based on a strain value of the main part of the connection fixing tool detected by the strain gauge in a state where tension is applied to the PC cable. To do.

The invention according to claim 3
It is the tension | tensile_strength estimation method of the PC cable of Claim 2, Comprising:
A part of the sheath is slidable in advance in half.

The invention according to claim 4
At the same time, fix the end of the PC cable formed from a plurality of lines that are tensioned to the fixing tool, and attach a strain gauge to the main body of the fixing tool.
The tension force of the PC cable is estimated based on the strain value of the fixing device main body portion detected by the strain gauge in a state where the tension force is applied to the PC cable.

  According to the present invention, since it is possible to measure tension on the axis of the PC cable without attaching new equipment, the PC cable member size is not greatly increased, and the PC cable is not greatly expanded. Can be estimated directly and easily.

It is sectional drawing of the connection fixing tool part which shows the structure of one Embodiment to which this invention is applied. It is sectional drawing of an Amsler testing machine. It is a top view of the tension test apparatus of one PC cable connected with the connection fixing tool. It is the front view (a) and side view (b) of the spacer ring of FIG. It is a longitudinal cross-sectional view of the spacer ring part of FIG. It is a figure which shows the sheath arrangement | positioning which lets a plurality of PC cables pass. It is process drawing which shows the state which inserted the PC cable in the sheath of FIG. It is process drawing which shows the state which slid and opened the sheath of FIG. It is process drawing which shows the state which cut | disconnected the PC cable of FIG. It is process drawing which shows the state which connected the cut | disconnected PC cable of FIG. 9 with the coupler. It is process drawing which shows the state which connected the leader line of the strain gauge of FIG. 10 to the management computer. FIG. 6 is a cross-sectional view of a connection fixing tool portion of Embodiment 2. FIG. 6 is a cross-sectional view of a connection fixing tool portion according to a third embodiment. FIG. 6 is a cross-sectional view of an end fixing tool portion according to a fourth embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
<Overview 1>
Of the connection fixing tools used to connect PC cables, one that connects cables one by one is placed at an arbitrary position, and a strain gauge is attached to the outer surface of the connection fixing tool main body to perform tension. This makes it possible to directly and easily estimate the tension force of a PC cable at an arbitrary position, without being limited to the tension end, without excessively increasing the dimensions of the PC structure member and converting it into a compression force. it can.

  FIG. 1 shows a connection fixing part as a configuration of an embodiment to which the present invention is applied. 1 is a PC cable and 2 is a connection fixing part.

As shown in the figure, the connection fixing tool 2 is a steel cylinder and has a pair of tapered sleeves 3, and the wedges 4 for gripping the end portions of the PC cable 1 are respectively stored in the sleeves 3. .
And the strain gauge 5 by the uniaxial gauge for shear strain is provided in the cylindrical main-body part of the connection fixing tool 2. FIG.

That is, one PC cable 1 is cut / separated at an arbitrary position, and the cutting / separating part of the PC cable 1 is connected by the connection fixing tool 2.
Two strain gauges 5 are attached to the center of the outer periphery of the cylindrical main body of the connection fixing tool 2 so as to face each other in the diametrical direction.

Next, FIG. 2 shows an Amsler testing machine 100, where 101 is a wedge and 102 is a sleeve.
This Amsler testing machine 100 corresponds to a load such as 1,000 kN.

  Using such an Amsler testing machine 100, various tensile forces are applied to the PC cable 1, strain values detected by the strain gauge 5 of the connection fixing device 2 corresponding to the various tensile loads are accumulated, and test actual measurement data Is recorded in the recording device.

  And the connection fixing tool detected with the strain gauge 5 using the appropriate management computer in the state which provided the tension | tensile_strength to the PC cable 1 in the arbitrary positions including the edge part of the pre-construction area of PC structure construction. Based on the strain value of the main body part 2, the recording device in which the various test actual measurement data described above are recorded is output as the tension of the corresponding PC cable 1.

FIG. 3 shows a tensile test apparatus 200 for the PC cable 1, wherein 201 is a jack, 202 is a drawing jig, 203 is a drawing jig, and 204 is a jack.
The tensile test apparatus 200 corresponds to a heavy load such as 10,000 kN.

  In FIG. 3, the two connection fixing tools 2 are arranged in a staggered manner as shown in the figure for downsizing.

  Using the tensile test apparatus 200 corresponding to such a large load, various tensile forces are applied to the PC cable 1 including the connection fixing device 2, and the strain value of the strain gauge 5 of the main body corresponding to the various tensile loads is obtained. It may be stored and recorded in a recording device as test actual measurement data.

  As described above, according to the connection fixing tool 2 of the embodiment, the strain value of the connection fixing tool 2 detected by the strain gauge 5 in a state where tension is applied to the PC cable 1 at an arbitrary position of the PC structure construction. In order to measure the tension force of the corresponding PC cable 1 on the basis, it is not necessary to extremely enlarge the member size of the PC structure, and the tension force of the PC cable 1 is directly applied not only at the tension end but also at an arbitrary position. And can be estimated easily.

  In FIG. 3, three spacer rings 6 are arranged before and after the two connection fixing tools 2 in order to prevent interference between the connection fixing tool 2 and the other PC cable 1.

  As shown in FIG. 4, the spacer ring 6 includes a pair of diametrically opposed five cable storage portions 61 and a pair of diametrically opposed pairs of the five cable storage portions 61 with a phase difference of 90 degrees. And a single cable storage groove 62.

  FIG. 5 shows the spacer ring 6 portion. As shown in the figure, the five PC cables 1 are collectively stored in the five cable storage portions 61 and connected to the single cable storage groove 62 by the connection fixing device 2. The PC cable 1 is housed alone.

  The lead wire of the strain gauge 5 is led out from a hose nipple 11a provided in the coupler sheath 11 as shown in FIG.

<Overview 2>
A part of the sheath into which the PC cable is inserted can be opened and closed in advance, a part of the plurality of PC cables inserted into the sheath is cut, the PC cable is reconnected with the connection fixing tool, and the connection fixing is performed. By attaching a strain gauge to the tool, the sheath including the part does not become extremely thick without passing the coupler inside the sheath, so that the member dimensions of the PC structure are not affected. It becomes possible.

  FIG. 6 shows a sheath arrangement for using the connection fixing body 2 of FIG. 1, and the coupler sheath 11 is composed of sheath split bodies 11A and 11B that are divided in the front and rear at the center in advance.

  Next, FIG. 7 is a process diagram showing a state in which the PC cable 1 is inserted into the sheath 21 and the coupler sheath 11 of FIG.

  Next, FIG. 8 is a process diagram showing a state in which the sheath split bodies 11A and 11B of the coupler sheath 11 of FIG.

  Next, FIG. 9 is a process diagram showing a state in which two PC cables 1 that face each other in the diameter direction in the PC cable 1 of FIG. 8 are cut.

  Next, FIG. 10 is a process diagram showing a state where the cut PC cable 1 of FIG. 9 is connected by the connection fixing tool 2. A strain gauge 5 is attached to the outer peripheral surface of the connection fixing tool 2, and the connection fixing tool 2. Before and after, a spacer ring 6 is arranged between the PC cables 1.

  Next, FIG. 11 is a process diagram showing a state in which the lead wire of the strain gauge 5 of FIG. 10 is led out from the hose nipple 11a and connected to the management computer.

  In this way, the PC cable 1 is cut and separated at the opening of the coupler sheath 11 where the sheath division bodies 11A and 11B are opened, and the cut and separated portions of the PC cable 1 are connected one by one with the connection fixing tool 2. Then, the strain gauge 5 may be attached to the cylindrical main body portion of the connection fixing tool 2 again.

  In this way, a part of the PC cable 1 is cut / separated, and the cut / separated portions of the PC cable 1 are reconnected one by one by the connection fixing tool 2, and the main body of the connection fixing tool 2 is connected. Since the strain gauge 5 is affixed, the sheath 21 including the coupler sheath 11 does not become extremely thick without allowing the connection fixing tool 2 to pass through the inside of the sheath 21 and affects the member size of the PC structure. Absent.

(Modification)
In the above embodiment, a part of a plurality of PC cables is cut / separated, and the cutting / separating parts of the PC cables are reconnected one by one with the connection fixing tool, but the entire PC cable is cut.・ Separate and cut and separate the PC cable cutting / separating parts together with a connection fixing tool as described in the following embodiment, and attach a strain gauge to the cylindrical main body of the connection fixing tool. May be attached.

(Embodiment 2)
<Overview>
Among the connection fixing tools used for connecting PC cables, the type that connects multiple cables that are simultaneously tensioned together is placed at the end of the pre-construction section, and a strain gauge is attached to the main body to apply tension. By doing so, it is possible to directly and easily estimate the tension of the PC cable without attaching new equipment and without having to extremely increase the size of the PC structure.

  FIG. 12 shows a connection fixing part of the second embodiment, wherein 1 is a PC cable and 12 is a connection fixing part.

As shown in the drawing, the connection fixing tool 12 is a steel disk shape, has a plurality of pairs of tapered sleeves 13, and has wedges 14 for gripping the ends of the plurality of PC cables 1 from both sides. Each is stored in a sleeve 13.
A strain gauge 5 is provided on the main body portion of the connection fixing tool 12.

That is, the plurality of PC cables 1 are cut and separated at arbitrary positions, and the cutting / separating portions of the plurality of PC cables 1 are collectively connected by the connection fixing tool 12.
Two strain gauges 5 are attached to the center of the outer periphery of the connection fixing tool 12 so as to face each other in the diametrical direction as in the first embodiment.

  In the above, using an appropriate tensile test apparatus, various tensile forces are applied to the connected PC cable 1 and the connection fixing device 12, and the strain values detected by the strain gauge 5 corresponding to the various tensile loads are accumulated. Then, it is recorded in the recording device as test actual measurement data.

  And, for example, at the end of the pre-construction section of the PC structure construction, the main body portion of the connection fixing tool 12 detected by the strain gauge 5 using an appropriate management computer in a state where tension is applied to the PC cable 1 Is output as a tension force of the corresponding PC cable 1 from the recording device in which the various test actual measurement data described above are recorded.

(Embodiment 3)
FIG. 13 shows a connection fixing part of the third embodiment, wherein 1 is a PC cable and 22 is a connection fixing part.

  As shown in the figure, the connection fixing tool 22 is made of steel, has a plurality of cable through holes 23 on both side flanges, and passes the end portions of the plurality of PC cables 1 from both sides through the cable through holes 23, respectively. A steel sleeve 24 is caulked to the end of the PC cable 1 and is engaged with flanges on both sides.

  In this way, the cutting / separating portions of the plurality of PC cables 1 are collectively connected by the connection fixing tool 22, and the connection fixing tool 22 faces the center of the outer periphery of the connection fixing tool 22 in the diametrical direction as in the first embodiment. Two strain gauges 5 may be attached.

(Embodiment 4)
FIG. 14 shows an end fixing unit portion according to the fourth embodiment, where 1 is a PC cable and 32 is an end fixing unit.

As shown in the drawing, the end fixing device 32 is a steel disk shape, has a plurality of tapered sleeves 33, and holds the end portions of the plurality of PC cables 1 from one direction on one side. The wedges 34 are stored in the sleeves 33, respectively.
A strain gauge 5 is provided on the main body portion of the end fixing tool 32.

That is, the plurality of PC cables 1 are fixed together by the end fixing tool 32 at the tension end.
Two strain gauges 5 are attached to the center of the outer periphery of the end fixing device 32 so as to face each other in the diametrical direction.

  Thus, when measuring by a tension | tensile_strength part, what is necessary is just to arrange | position a PC cable to one direction and to measure a distortion value.

(Other variations)
In addition, as a tensile test apparatus, not only embodiment but various things can be used.

DESCRIPTION OF SYMBOLS 1 PC cable 2 Connection fixing tool 3 Sleeve 4 Wedge 5 Strain gauge 11 Sheath 12 Connection fixing tool 13 Sleeve 14 Wedge 21 Sheath 22 Connection fixing tool 23 Cable through-hole 24 Steel sleeve 32 End fixing tool 33 Sleeve 34 Wedge 100 Tensile test Device 200 Tensile test device

Claims (4)

Cut or separate a PC cable formed from one or more simultaneously tensioned at any position, connect the PC cable cutting / separating part with a connecting fixing tool, and connect the strain gauge to the main body of the connecting fixing tool. Paste
The tension force of the PC cable is estimated based on the strain value of the main part of the connection fixing tool detected by the strain gauge in a state where the tension force is applied to the PC cable. Estimation method. An arbitrary part of the sheath into which a plurality of PC cables that are simultaneously tensioned can be opened and closed in advance, and a part or all of the PC cable is cut and separated at an opening part where the part of the sheath is opened. , Reconnect the PC cable cutting / separating parts one by one or all at once with a connection fixing tool, and attach a strain gauge to the cylindrical main body of the connection fixing tool,
The tension force of the PC cable is estimated based on the strain value of the main part of the connection fixing tool detected by the strain gauge in a state where the tension force is applied to the PC cable. Estimation method.   3. The method of estimating tension of a PC cable according to claim 2, wherein a part of the sheath can be slid in advance in half. At the same time, fix the end of the PC cable formed from a plurality of lines that are tensioned to the fixing tool, and attach a strain gauge to the main body of the fixing tool.
In the state where tension is applied to the PC cable, the tension of the PC cable is estimated based on the strain value of the fixing device main body portion detected by the strain gauge. Method.

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