JP2006337058A - Load measuring method for existing anchor and re-tensing method for existing anchor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the purpose of enhancing work efficiency at the time of load measurement, re-tensing thereafter, and re-fixation, and enhancing the reliability of the work, without being followed by structure complication, etc. <P>SOLUTION: Re-tensing bolts 28 are screwed on separate three positions out of screw holes 12a in a support head 12 fixedly locked on a tension member 16, with the re-tensing bolts 28 capable of pulling the tension member in a direction that tenses the tension member by screwing into the screw holes, while a load cell 34 is disposed on each re-tensing bolt 28 so that it can be pinched by each re-tensing bolt concurrently with the screw-in of the re-tensing bolt 28. The tension member 16 is pulled by the screw-in of each re-tensing bolt 28 relative to the screw holes 12a in the support head. The total of measurement values by the respective load cells 34 is measured and acknowledged as a fixed load or re-tensing load of an existing anchor, with the measurement values obtained by measurement at the time point when the support head is raised by a prescribed amount in company with the tension member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a load measuring method for an existing anchor that measures the fixing load of an existing anchor that has been constructed and fixed, and a method for re-tensioning an existing anchor that is re-tensioned and held and fixed in the re-tensioned state. .

  Anchors constructed for the purpose of reinforcement and stabilization of the ground, structures, etc., so-called ground anchors, are tensions generated in the free length by pulling and tensioning of the tension material solidified on the ground. Since the force is transmitted and applied to the ground, structures, etc. as the fixing load, for example, if the tension, that is, the fixing load decreases due to displacement of the ground, etc. due to secular change or elongation of the tensile material, the anchor Accompanied by a decrease in its functionality. Therefore, normally, the soundness level is inspected almost regularly, and when it is determined that the fixing load has decreased, the existing anchor is re-tensioned to maintain the functionality as an anchor for a long period of time. It has been broken.

  By the way, when inspecting the soundness of such an anchor that has been constructed and fixed, that is, an existing anchor, it is usually performed by towing the existing anchor and measuring its load to evaluate its soundness. Is called. However, the hydraulic center hole jack that is generally used for towing the existing anchor can be recognized as a relatively heavy heavy-duty equipment, and it only requires a considerable amount of labor for its movement and installation. There is also a need for the implementation of the construction equipment, such as the construction of large-scale scaffolding on the slopes where the anchors are constructed and the installation of cranes. Therefore, the integrity of existing anchors using such center hole jacks is required. It cannot be denied that this inspection is likely to be accompanied by a decrease in workability and safety.

  Here, one method for measuring the fixing load of an existing anchor without using such a large center hole jack is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-267593.

  The existing anchor exemplified in this publication has a configuration in which a tension member (anchor body) is tension-fixed by tightening a tightening nut on a fixing washer with respect to a predetermined male thread portion. In this known method, the fixing washer is fixed. A substantially cylindrical support base and an annular load cell are sequentially arranged on a receiving washer placed around the base, and this tightening is done by tightening the loading nut at the top of the load cell until no load is applied by the tightening nut. The fixing load of the existing anchor is measured by the load cell sandwiched between the two. When it is determined that the fixed load is lower than the design load at the beginning of the construction, the tension of the tensile material is recognized while the load cell recognizes the load by further tightening the loading nut up to a predetermined re-tension load. After the tension material is re-tensioned up to the predetermined re-tension load, the tension nut is screwed until it comes into contact with the fixing washer, and then the loading nut is loosened to maintain the re-tension state by the predetermined re-tension load. The present invention is configured as described above.

  However, since this known configuration is a configuration in which tension is obtained by tightening a loading nut with respect to a single threaded portion (bolt-shaped rod body) provided integrally with the tensile material, the tensile material The tensile load is concentrated at one point. In this known configuration, since the loading nut is manually rotated by a wrench or the like, it is naturally expected that workability is reduced due to an increase in the size of a tool such as the wrench.

  In addition, since this single male thread part and loading nut are also required to have sufficient rigidity to withstand the pulling and tensioning of the tensile material, the male thread part and the loading nut are increased in size (large diameter). The increase in cost due to conversion is inevitable.

  Here, in the accurate load measurement by the annular load cell, it is required to apply an equal load to the pressure receiving surface. Therefore, in this known configuration, by forming the portion of the support table facing the insertion hole of the receiving washer in a spherical shape, the support table can be inclined with respect to the ground surface, that is, the load cell pressure receiving surface can be adjusted in inclination. It is said.

  However, whether or not the pressure-receiving surface of the load cell is arranged orthogonally to the axis of the tensile material must be roughly determined based on the operator's scale, so in this known configuration, load measurement is not possible. It cannot be denied that it may be inaccurate.

And in the case where the tensile material is a plurality of PC steel strands, not only at the time of load measurement, but also at the time of re-tensioning and re-fixation, the applied load is equalized, that is, applied to each PC steel strand. Load equalization is required. However, in this known configuration, the success or failure of equalization of the applied load on each PC steel wire depends on the inclination adjustment of the support base with respect to the axis of the tensile material, depending on the operator's scale. In addition to the load measurement, this known configuration is inferior in its re-tensioning and re-fixation accuracy.
JP 2002-267593 A

  The problem to be solved is that the workability at the time of load measurement and at the time of subsequent re-tensioning and at the time of re-fixing tends to deteriorate, and the accuracy of the work tends to be inferior.

  According to a first aspect of the present invention, there is provided a method for measuring a load on an existing anchor, comprising: a support head fixedly locked to at least one of a tension member and an anchor head; At least three of them are screwed with re-tensioning bolts that can pull the tension material in the direction of tension by screwing the screw holes, and can be pinched with the re-tensioning bolts. In addition, a predetermined load cell is arranged for each re-tension bolt, and when the tension member is pulled under the screwing of each re-tension bolt with respect to the screw hole, the support head is lifted by a predetermined amount with the tension member. The most important feature is to measure and recognize the total measured value of each load cell as the anchoring load of the existing anchor.

  According to a second aspect of the present invention, in the load measuring method according to the first aspect of the present invention, the re-tensioning bolt mounted on the annular load cell is disposed by grounding to the support plate with respect to the screw hole of the support head. The re-tension bolt is screwed from above through a predetermined bolt base insertion hole, and the re-tension bolt is screwed to the support head along with the tightening rotation of the re-tension bolt using the bolt base as a support base. The most important feature is that the load cell is clamped between the head and the bolt base, and the tension member is pulled in the tension direction by pulling up the support head accompanying the screwing of the re-tension bolt.

  According to a third aspect of the present invention, in the load measuring method according to the first aspect, a load cell is interposed between the re-tensioning bolt screwed to the support head and the bearing plate, and the screw accompanying the tightening rotation of the re-tensioning bolt. The load cell is clamped between the tip of the re-tensioning bolt and the pressure plate with the protrusion of the support head from the support head toward the pressure-bearing plate, and the re-tensioning bolt is screwed. The main feature is that the tension member is pulled in the tension direction by pushing up the support head against the bearing plate.

  The existing anchor re-tensioning method according to the fourth aspect of the present invention is a series of screws provided at at least six equidistant positions on a support head fixedly locked to at least one of a tension member and an anchor head. Retightening bolts that allow pulling of the tensile material in the tension direction by screwing the screw holes are screwed into at least three spaced apart positions of the holes, and the screws of the retightening bolts are screwed. A predetermined load cell is arranged for each re-tensioning bolt, and the tensioning material is pulled under the threading of each re-tensioning bolt with respect to the screw hole. From the total of the measured values at each load cell measured at the time of ascent, it is determined whether the existing anchor needs to be re-tensioned. Further re-tensioning of each re-tensioning bolt from the point is performed as a re-tensioning operation for the existing anchor, and the total of the measured values measured by each load cell at that time is measured and recognized as a re-tensioning load for the existing anchor. When the re-tensioning load reaches a predetermined set value, a predetermined fixing bolt is screwed into each remaining screw hole where the re-tensioning bolt is not screwed, and the re-tensioning position by the screwing of each fixing bolt is After supporting the support head, the load cell is removed by screwing out and removing all the re-tension bolts from the screw holes, and the fixing bolts screwed into the screw holes are used instead of the re-tension bolts. Its most important feature is that the support of the support head is added to the support of the fixing bolt that has been screwed in earlier, so that this is to maintain the existing anchor in the re-tensioned state. It is set to.

  According to a fifth aspect of the present invention, in the re-tensioning method according to the fourth aspect, the re-tensioning bolt mounted on the annular load cell is arranged with respect to the screw hole of the support head by grounding to the bearing plate. The re-tension bolt is screwed from above through a predetermined bolt base insertion hole, and the re-tension bolt is screwed to the support head along with the tightening rotation of the re-tension bolt using the bolt base as a support base. The most important feature is that the load cell is clamped between the head and the bolt base, and the tension member is pulled in the tension direction by pulling up the support head accompanying the screwing of the re-tension bolt.

  Further, according to a sixth aspect of the present invention, in the re-tensioning method of the fourth aspect, a load cell is interposed between the re-tensioning bolt screwed to the support head and the bearing plate, and the screw accompanying the tightening rotation of the re-tensioning bolt. The load cell is clamped between the tip of the re-tensioning bolt and the support plate by the protrusion of the re-tensioning bolt from the support head toward the support plate under the screwing with respect to the hole. The main feature is that the tension member is pulled in the direction of tension by pushing up the support head against the bearing plate as it advances.

  According to the load measuring method of the existing anchor of the present invention according to claim 1, load cells are provided at a plurality of locations, and the equality of traction and tension can be specifically recognized as measured values for each load cell. Load measurement in a uniform tension state without bias can be easily ensured. Therefore, the advantage that the accuracy of the load measurement is reliably improved can be obtained according to claim 1.

  And in this claim 1, since the tension material is pulled and tensioned by screwing of at least three re-tension bolts with respect to the support head, the load load with a single re-tension bolt is distributed by the dispersion. Reduced reliably. In other words, since excessive work is not required for the screw rotation operation for each re-tension bolt, the workability can be sufficiently improved with the downsizing of the manual tool, and the labor burden on the operator is reduced. Also in this respect, the advantage that the workability is surely improved can be obtained according to the first aspect.

  Further, according to the first aspect, since the tension material is pulled and tensioned by at least three separate re-tensioning bolts, the uniform traction and tension corresponding to the inclination of the ground surface is screwed by each re-tensioning bolt. It can be secured easily by adjusting the amount of advance. Therefore, the advantage that the load measuring method excellent in adaptability to the slope change can be easily secured can be obtained according to the first aspect.

  The second and third aspects of the present invention have the advantage that the load measuring method of the first aspect can be more appropriately performed.

  Further, according to the method for re-tensioning an existing anchor of the present invention according to claim 4, it is possible to easily re-tension and re-fix the existing anchor that has been continued in the load measurement by the load measuring method of claim 1 above. There are advantages.

  And in order to measure the fixed load and re-tension load of the existing anchor as the total value of the measured values at the load cells arranged at multiple locations, the load values at each location are equalized by recognizing the measured values of each load cell Can be easily measured. Therefore, even when the tensile material is a plurality of PC steel wires, it is possible to sufficiently equalize the load load on each PC steel wire at the time of load measurement, re-tensioning, and re-fixing, Thus, the advantage that the certainty of the re-tensioning and re-fixing work is improved can be obtained according to claim 4.

  Further, claims 5 and 6 of the present invention have an advantage that the re-tensioning method of claim 4 can be more appropriately performed.

  The purpose of improving workability at the time of load measurement, subsequent re-tensioning and re-fixing, and improving the certainty of the work can be realized without complicating the configuration.

  1 and 2 are a schematic longitudinal sectional view and a schematic exploded perspective view of a re-tensioning device 10 used in performing the load measuring method for an existing anchor and the re-tensioning method for an existing anchor according to the present invention, As can be seen from the above, in the present invention, the support head 12 having a predetermined plurality of screw holes 12a is fixedly locked to, for example, the tension member 16 as a pulling member of an existing anchor. The pulling / tensioning technique is limitedly embodied as pulling the tension member by screwing the re-tensioning bolt 28 to the screw hole of the support head.

  As can be seen from FIG. 3 in addition to FIG. 1 and FIG. 2, the anchor (ground anchor) constructed for the purpose of reinforcing and stabilizing the ground, structures, etc. is a fixed portion (not shown) in the ground. Tensile material 16, such as a predetermined number of PC steel wires, is pulled under a predetermined traction force and placed on a bearing plate 20 on the structure 18 with respect to its extended end 16a. The anchor head 22 that can be combined is fixedly locked by the wedge 24, so that the tension force can be applied to the structure and the ground as a fixing force.

  The overall basic structure of this type of anchor (existing anchor) is known, and the structure itself is not the gist of the present invention, so a detailed description thereof will be omitted here.

  Here, in the measurement of the fixing load of the existing anchor and the subsequent re-tensioning, it is required to pull the tension member 16 of the existing anchor in its fixed form. Therefore, as shown in FIGS. 1 and 2, in the present invention, the support head 12 serving as the traction member is integrally locked to at least one of the tension member 16 and the anchor head 22.

  In this embodiment, the support head 12 is fixedly locked to the extension end 16 a of the tensile material from the anchor head 22 via a wedge 26.

  The support head 12 is provided with at least three screw holes 12a, for example, in a penetrating manner. In this embodiment, the number is limited to six at 60 ° intervals. In the present invention, among the six screw holes 12a of the support head 12, the re-tension bolts 28 are screwed at three spaced positions, for example, every other three positions, leaving at least three spaced positions. The re-tensioning device 10 is configured to pull the tension member 16 by the retraction of the re-tensioning bolt with respect to the screw hole.

  As shown in FIGS. 1 and 2, in the first embodiment of the present invention, the insertion of a hollow bolt base 30 in which a re-tensioning bolt 28 is disposed with grounding of its lower end to the bearing plate 20. A load cell 34 that is screwed into the screw hole 12a of the support head from above through the hole 32 and that can detect and measure a pinching load is provided for each re-tension bolt. .

  As the load cell 34, a commercially available annular one that can be mounted around the re-tension bolt 28 is used, and the bolt head 28 a that is screwed to the screw hole 12 a, that is, the re-tension bolt with respect to the support head 12, It mounts on this bolt stand so that the pinching pressure between the bolt stands 30 is possible.

  In addition, since the load cell 34 used here is a commercially available general one, it is conceivable that the re-tension bolt used in the present invention may not be easily engaged and pinched by the bolt head 28a. By utilizing a collar or the like for receiving the bolt head shown as reference numeral 36 in FIG. 2, the allowable range of usable load cells is sufficiently expanded.

  In such a configuration, the re-tensioning bolt 28 tries to screw with respect to the support head 12 by rotating the re-tensioning bolt 28 in the tightening direction (tightening rotation) with a corresponding manual wrench or the like. Since the bolt head 28a is held at a constant height by the engagement with the collar 36 of the load cell, the support head is accompanied by the tension member 16 under the rotating operation of the re-tensioning bolt in the tightening direction. Pulled up. That is, the tension member 16 is pulled and tensioned by an amount corresponding to the pulling-up by the pulling-up of the support head 12 accompanying the rotation operation of the re-tensioning bolt 28 in the tightening direction.

  In the present invention, a load cell 34 is provided for each re-tensioning bolt 28. That is, the tensile load by each of the re-tension bolts 28 is individually detected and measured by the load cell 34 for each of the re-tension bolts. It is possible to measure and recognize a large tensile load and thus a fixing load of the existing anchor.

  For example, as shown in FIG. 4, by measuring the tensile load at the point where the load from the anchor head 22 is not applied to the bearing plate 20, that is, at the point of separation of the anchor head from the bearing plate. It can be regarded as the fixing load of the tension member 16, that is, the existing anchor.

  The anchor head 20 is lifted and separated from the bearing plate 22 by, for example, a lifting amount (floating amount) of the support head 12 by a displacement meter (not shown) disposed through the center hole 38 of the bolt base 30. ) Can be detected and recognized. Then, by preliminarily defining the measurement point as a predetermined lifting amount of the support head 12, proper measurement of the fixing load is sufficiently possible.

  As described above, according to the load measuring method of the existing anchor of the present invention, the existing anchor is obtained by rotating the three re-tension bolts 28 around the load cell 34 in the tightening direction (screwing and rotating operation). Traction and fixing load can be measured. In other words, the tension work and fixing load measurement can be easily performed without using large equipment such as a center hole jack, so the workability is greatly improved compared to work using a center hole jack. .

  And in this invention, in order to obtain traction of the tension | tensile_strength material 16 by the re-tension bolt 28 spaced apart by at least three places, the burden load with one re-tension bolt will fully be reduced. In other words, compared with the rotation work of the nut at one place as disclosed in JP-A-2002-267593, the work effort at one place of the re-tensioning bolt 28 is sufficiently reduced. According to the present invention in which the size of the manual tool is reduced, the workability is surely improved as compared with this known configuration.

  Further, since the load cell 34 for measuring the fixing load is provided for each re-tensioning bolt 28, uniform tension while individually confirming the measured load can be easily ensured in the present invention. Therefore, the accuracy of the load measurement is reliably improved.

  By the way, the fixing load of such an existing anchor is a judgment material for evaluating the soundness of the existing anchor, and the fixing load measured here is largely determined from a predetermined set value, for example, a design load at the beginning of construction. In the case where it has been lowered, the re-tensioning, that is, the further pulling of the tension member 16 and the re-fixation are required. Therefore, the re-tensioning method for the existing anchor according to the present invention is embodied as one that can be continued to the load measurement by the above-described load measurement method.

  For example, when it is determined that re-tensioning is necessary due to the fixing load of the existing anchor measured as the sum of the measured values at the load cell 34 arranged for each of the three re-tensioning bolts 28, the existing anchor shown in FIG. From the load measurement state, the tension member 16 is further pulled as shown in FIG. 5, for example, by further raising the support head 12 by further screwing each re-tensioning bolt with a manual wrench or the like. Then, when it is determined that the total of the measured values at each load cell 34 that has fluctuated due to the lifting of the support head 12, that is, the tensile load on the tensile material 16 has reached a predetermined set value, the work is performed by re-tensioning the existing anchor. The work is shifted to the re-fixing work in the re-tensioned state.

  As shown in FIGS. 6 and 7, in this re-fixing operation, first, a predetermined fixing bolt 40 is inserted into each remaining screw hole of the support head screw hole 12a where the re-tension bolt 28 is not screwed. , And the support head 12 is supported at the re-tensioned position by screwing each fixing bolt to a tightening position at which the measurement value at each load cell 34 does not fluctuate. Then, by retraction and removal of all the re-tension bolts 28 from the screw holes 12a, each load cell 34 is removed as shown in FIG. 8, and as shown in FIG. Instead, another fixing bolt 40 is similarly screwed into each screw hole 12a of the support head, and the support head 12 is then supported by the fixing screw that is screwed later. By adding to the support, this is maintained as a re-fixation of the existing anchor in the re-tensioned state.

  As described above, according to the existing anchor re-tensioning method of the present invention, continuous execution from the load measurement by the load measurement method can be easily performed. In other words, after the fixing load of the existing anchor is measured by the load measuring method, if it is determined that re-tensioning is necessary, it is sufficient to further rotate each re-tensioning bolt 28 from the state as it is. Transition to and implementation of tension work is easily possible, and the workability is surely improved.

  And, this re-tensioning method is a configuration in which re-tensioning of the tension member 16 is obtained by screwing of a plurality (three places) of re-tensioning bolts 28 that are spaced apart from each other equally with respect to the support head 12. Since the traction force at each position can be adjusted by adjusting the screwing amount of each re-tensioning bolt, even an existing anchor using a plurality of PC steel strands as the tension member 16 as shown in the drawing is different from each PC steel. It is easy to pull and tension the line evenly.

  Furthermore, since re-tensioning work can be performed while confirming the measurement values at each load cell 34, even when the tensile material 16 is a plurality of PC steel strands, the load is measured, re-tensioned, and re-tensioned. It is possible to equalize the load load on each strand of PC steel at the time of fixing. This improves the certainty of re-tensioning and re-fixing work, and at the same time, more than multiple PC steels. Applicability to existing anchors using wire as a tensile material is also improved.

  Here, in the above-described embodiment, the number of the screw holes 12a of the support head is embodied as six places separated by equal intervals (60 °), but this is the minimum of the re-tension bolt 28 and the fixing bolt 40. Since the number is based on the premise of the required number of three places, it is sufficient that the number is six or more, and is not limited to these six places. However, the increase in the number of the re-tensioning bolts 28 and the fixing bolts 40 may be accompanied by a complicated configuration and complicated work, so that the minimum necessary to enable stable pulling and holding of the tensile material 16 is required. By adopting the six places, it is possible to sufficiently prevent the complication of the configuration and the complexity of the work.

  Considering that the minimum required number of re-tension bolts 28 at the time of re-tensioning of the existing anchor is three, when only the load measurement of the existing anchor is performed, the number of screw holes 12a of the support head is re-set. It is possible to have three locations corresponding to the number of tension bolts.

  Further, in this embodiment, the support head 12 is fixedly locked to the tension member 16, but the tension member is integrally pulled under the screwing of the re-tensioning bolt 28 with respect to the support head. Since it is sufficient if possible, the present invention is not limited to this. For example, the support head may be integrated around the anchor head 22.

  By the way, in the first embodiment described above, the tension member 16 is pulled by pulling up the support head 12 by the re-tension bolt 28. However, the present invention is not limited to this. That is, the tension material may be pulled or re-tensioned.

  As can be seen from FIGS. 10 and 11, in this push-up type re-tensioning apparatus 110 according to the second embodiment, it is possible to pinch with a re-tensioning bolt 28 that is screwed with respect to the support head 12. The load cell 34 is interposed between the bearing plate 20 and the support head 12.

  In this configuration, a tray 42 that receives the tip of the re-tension bolt 28 is provided for the load cell 34.

  In addition, the first embodiment described above and the second embodiment are different from each other in the configuration of the bolt base 30, and there are many common parts in the other portions, so the first embodiment described above. About the same component as an example, the detailed description in this 2nd Example is abbreviate | omitted by attaching | subjecting the same referential mark.

  According to such a configuration, the tension member 16 is pulled and tensioned by pushing up the support head with the load cell receiving tray 42 as a base point as the re-tensioning bolt 28 is screwed with respect to the support head 12. Then, for example, as shown in FIG. 12, the fixing load of the existing anchor is measured by measuring the tensile load at the separation flying point of the anchor head 22 from the bearing plate 20 as the sum of the measured values at each load cell 34.

  Further, when it is determined that the existing anchor is in need of re-tensioning due to this fixing load, the re-tensioning bolt 28 is further screwed by a manual wrench or the like from the load measurement state of the existing anchor shown in FIG. The tension member 16 is further pulled as shown in FIG. 13, for example. Then, when it is determined that the total of the measured values at each load cell 34 that has fluctuated due to the lifting of the support head 12, that is, the tensile load on the tensile material 16 has reached a predetermined set value, the work is performed by re-tensioning the existing anchor. The work is shifted to the re-fixing work in the re-tensioned state.

  As shown in FIGS. 14 and 15, in this re-fixing operation, first, a predetermined fixing bolt 40 is inserted into each remaining screw hole of the support head screw hole 12a where the re-tension bolt 28 is not screwed. , And the support head 12 is supported at the re-tensioned position by screwing each fixing bolt to a tightening position at which the measurement value at each load cell 34 does not fluctuate. Then, by retraction and removal of all the re-tension bolts 28 from the screw holes 12a, each load cell 34 is removed as shown in FIG. 16, and as shown in FIG. Instead, another fixing bolt 40 is similarly screwed into each screw hole 12a of the support head, and the support head 12 is then supported by the fixing screw that is screwed later. By adding to the support, this is maintained as a re-fixation of the existing anchor in the re-tensioned state.

  That is, even under the re-tensioning device 110 shown as the second embodiment, both the load measuring method and the re-tensioning method similar to the re-tensioning device 10 shown in the first embodiment can be appropriately performed. .

  The above-described embodiments are for explaining the present invention, and do not limit the present invention. All modifications, alterations, and the like within the technical scope of the present invention are included in the present invention. It goes without saying that it is done.

  The tensile material is not limited to a strand made of PC steel, and the above configuration can be applied to a PC steel rod, a lock bolt, and the like.

It is the general | schematic process figure before the re-tension which also serves as the general | schematic longitudinal cross-sectional view of the re-tension apparatus in 1st Example used when performing the load measuring method and re-tension method of the existing anchor of this invention. It is a schematic exploded perspective view of the re-tensioning apparatus shown in FIG. It is a schematic front view of the part fracture | rupture which shows the head fixing | fixed part of the existing anchor. It is a schematic process drawing in the re-tensioning device shown in FIG. 1 at the time of load measurement. It is a schematic process drawing in the re-tensioning device shown in FIG. 1 at the time of re-tensioning. It is a schematic process drawing in the re-tensioning device shown in FIG. 1 at the time of holding after re-tensioning. FIG. 2 is a schematic exploded perspective view showing a holding operation process after re-tensioning in the re-tensioning apparatus shown in FIG. 1. It is a schematic process drawing in the re-tensioning apparatus shown in FIG. It is a schematic process drawing in the re-tensioning device shown in FIG. It is the general | schematic process figure before the re-tension which also serves as the general | schematic longitudinal cross-sectional view of the re-tension apparatus in 2nd Example used when performing the load measuring method and re-tension method of the existing anchor of this invention. FIG. 11 is a schematic exploded perspective view of the re-tensioning device shown in FIG. 10. FIG. 11 is a schematic process diagram in the re-tensioning device shown in FIG. 10 during load measurement. FIG. 11 is a schematic process diagram of the re-tensioning apparatus shown in FIG. 10 during re-tensioning. FIG. 11 is a schematic process diagram in the re-tensioning device shown in FIG. 10 during holding after re-tensioning. FIG. 11 is a schematic exploded perspective view showing a holding operation process after re-tensioning in the re-tensioning apparatus shown in FIG. 10. FIG. 11 is a schematic process diagram in the re-tensioning apparatus shown in FIG. 10, showing after the re-tensioning bolt is removed. FIG. 11 is a schematic process diagram in the re-tensioning apparatus shown in FIG. 10 showing a re-fixing state.

Explanation of symbols

10,110 Re-tensioning device 12 Support head 16 Tensile material 20 Bearing plate 22 Anchor head 28 Re-tension bolt 30 Bolt stand 34 Load cell 40 Fixing bolt

Claims (6)

The tensile material is fixed under a predetermined load by the fixed engagement of the anchor head that is engaged with and placed on the bearing plate with respect to the tensile material that is tensioned with consolidation of the fixing portion to the ground or the like. It is a method of measuring the load of an existing anchor that is fixed in tension,
The support head fixedly locked to at least one of the tension member and the anchor head has at least three of the series of screw holes provided at three spaced positions, and the screw heads are screwed into the screw holes. Screwing a re-tensioning bolt that enables the tension material to be pulled in the tension direction by means of a screw, and a predetermined load cell is provided for each re-tensioning bolt so that the holding force can be held as the re-tensioning bolt is screwed. And
The total of the measured values at each load cell measured when the tensile material is pulled under the screwing of the re-tensioning bolt with respect to the screw hole and the support head is lifted by a predetermined amount with the tensile material. The load measuring method of the existing anchor which is measured and recognized as the fixing load of the existing anchor. The re-tension bolt mounted on the annular load cell is screwed from above through the insertion hole of a predetermined bolt base arranged by grounding to the support plate with respect to the screw hole of the support head. Wearing,
The load cell is clamped between the head of the re-tensioning bolt and the bolt base by screwing of the re-tensioning bolt with respect to the support head accompanying the tightening rotation of the re-tensioning bolt using the bolt base as a support base. The load measuring method for an existing anchor according to claim 1, wherein the tension member is pulled in a tension direction by pulling up the support head accompanying the screwing of the re-tension bolt. The load cell is interposed between the re-tension bolt screwed to the support head and the bearing plate,
The tip of the re-tension bolt, the support plate, along with its protrusion in the direction of the support plate from the support head under screwing with respect to the screw hole accompanying the tightening rotation of the re-tension bolt, 2. The existing anchor according to claim 1, wherein the load cell is clamped between the tension members and the tensile material is pulled in the tension direction by pushing up the support head against the bearing plate as the re-tensioning bolt is screwed. Load measurement method. The tensile material is fixed under a predetermined load by the fixed engagement of the anchor head that is engaged with and placed on the bearing plate with respect to the tensile material that is tensioned with consolidation of the fixing portion to the ground or the like. It is a re-tensioning method for existing anchors that are fixed in tension,
At least three spaced apart portions of a series of screw holes provided in at least six equidistant positions of the support head fixedly locked to at least one of the tension member and the anchor head. In addition, a re-tension bolt that allows the tension member to be pulled in the direction of tension by screwing the screw hole to the screw hole and screwing the re-tension bolt in accordance with the screw advance are provided. For each re-tension bolt,
The tension member is pulled while the re-tension bolt is screwed into the screw hole, and the required value of the existing anchor is calculated based on the total measured value at each load cell when the support head is lifted by a predetermined amount. When it is determined whether or not re-tensioning is necessary, and it is determined that re-tensioning is necessary based on the fixing load, further re-tensioning of each re-tensioning bolt from that point is performed as a re-tensioning operation for the existing anchor. Measuring and recognizing the total of the measured values measured by the load cell as a re-tension load on the existing anchor,
When the re-tension load reaches a predetermined set value, a predetermined fixing bolt is screwed into each of the remaining screw holes where the re-tension bolt is not screwed. After the support head is supported at the tension position, each re-tension bolt is screwed out and removed from the screw hole, and each load cell is removed, and the fixing bolt screwed into each screw hole instead of the re-tension bolt A method for re-tensioning an existing anchor, in which the support of the support head is added to the support by the fixing bolt that has been previously screwed to maintain the existing anchor in the re-tensioned state. The re-tension bolt mounted on the annular load cell is screwed from above through the insertion hole of a predetermined bolt base arranged by grounding to the support plate with respect to the screw hole of the support head. Wearing,
The load cell is clamped between the head of the re-tensioning bolt and the bolt base by screwing of the re-tensioning bolt with respect to the support head accompanying the tightening rotation of the re-tensioning bolt using the bolt base as a support base. The existing anchor re-tensioning method according to claim 4, wherein the tension member is pulled in a tension direction by pulling up the support head accompanying the screwing of the re-tension bolt. The load cell is interposed between the re-tension bolt screwed to the support head and the bearing plate,
The protrusion of the re-tension bolt and the support plate is caused by the protrusion of the re-tension bolt in the direction of the support plate under the screwing with respect to the screw hole with the tightening rotation of the re-tension bolt. 5. The re-tensioning of the existing anchor according to claim 4, wherein the load cell is clamped between them and the tensile material is pulled in the tensioning direction by pushing up the support head against the bearing plate accompanying the screwing of the re-tensioning bolt. Method.

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