A measuring device and method for measuring effective prestress of a prestressed beam

Abstract

The application relates to a measuring device and method for measuring the effective prestress of a prestressed beam, and belongs to the technical field of prestress measurement. The device comprises a mounting plate, a boss and a strain gauge. The strain gauge is fixed on a prestressed tendon. The mounting plate is provided with two mounting plates and is fixedly arranged on the prestressed tendon. The strain gauge is located between the two mounting plates. The boss is fixedly arranged on the mounting plate and faces the strain gauge. The connecting lead of the strain gauge passes through the boss and the mounting plate and then is led out from the prestressed beam along the running direction of the prestressed tendon. The cross sections of the mounting plate and the boss are circular. The measuring device further comprises a surrounding part. The surrounding part is used for sealing the strain gauge between the boss and the surrounding part by surrounding the bosses on both sides. The cross sections of the mounting plate and the boss are circular. The measuring device further comprises a surrounding part. The surrounding part is used for sealing the strain gauge between the boss and the surrounding part by surrounding the bosses on both sides. The application has the effect of facilitating the measurement of the prestress of the prestressed beam.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of prestress measurement, in particular to a measuring device and method for measuring effective prestress of a prestressed beam. BACKGROUND

[0002] The prestressed beam can overcome the maximum defect of the ordinary reinforced beam, i.e. the crack problem, due to its prestress, and the prestressed concrete structure can not only save steel material but also improve the structure function and solve the technical problems that other structure materials cannot solve, so the prestressed beam is widely used in large structures with high technical difficulty such as large bridges. The safety state of the prestressed beam during the service period is directly related to the size of the internal effective prestress, but as the service period increases, the structure prestress will gradually be lost, i.e. the stress in the prestressed tendon gradually decreases, so it is necessary to measure the effective prestress in the prestressed beam.

[0003] However, when measuring the effective prestress at present, it is usually necessary to partially destroy the prestressed beam to expose the prestressed tendon, and then a tensile force opposite to the prestress is applied to the prestressed tendon by clamping the prestressed tendon, when the applied tensile force completely offsets the prestress, i.e. the applied tensile force is the effective prestress of the prestressed tendon, but the destruction of the prestressed beam and the pulling of the prestressed tendon after the destruction of the prestressed beam will damage the integrity of the prestressed beam, so that the bearing capacity and deformation resistance of the prestressed beam after the measurement of the prestress cannot be restored and the difficulty of the measurement of the prestress is relatively large. SUMMARY

[0004] In order to facilitate the measurement of the prestress of the prestressed beam, the present application provides a measuring device and method for measuring the effective prestress of the prestressed beam.

[0005] In the first aspect, the present application provides a measuring device for measuring the effective prestress of the prestressed beam, which adopts the following technical scheme:

[0006] A measuring device for measuring the effective prestress of the prestressed beam, comprising a mounting plate, a boss and a strain gauge, the strain gauge is fixed on the prestressed tendon, the mounting plate is provided with two mounting plates and is fixedly arranged on the prestressed tendon, the strain gauge is located between the two mounting plates, the boss is fixedly arranged on the mounting plate and faces the strain gauge, and the connecting lead of the strain gauge passes through the boss and the mounting plate and then is pulled out from the prestressed beam along the running direction of the prestressed tendon;

[0007] The cross sections of the mounting plate and the boss are circular, and the measuring device further comprises a surrounding part, which is used for sealing the strain gauge between the boss and the surrounding part by surrounding the bosses on both sides;

[0008] The measuring device further comprises a dehumidifying part, which is used for discharging the humid air between the surrounding part and the boss to make the strain gauge in a dry environment.

[0009] Optionally, the enclosing member comprises a winding shaft, a waterproof film and a first driving member, the length direction of the winding shaft is parallel to the length direction of the prestressed tendon, the waterproof film is wound on the winding shaft, the two ends of the winding shaft are respectively located on the two bosses and cross the strain gauge, and the first driving member is used to drive the winding shaft to move around the boss to drive the waterproof film to be wrapped around and connected with the boss to seal the strain gauge.

[0010] Optionally, the surface of the mounting plate towards the strain gauge is provided with an annular groove, the boss is fixedly arranged in the middle of the annular groove, the two ends of the winding shaft are provided with mounting seats, the winding shaft is rotatably arranged on the mounting seat, the mounting seat is slidably arranged on the side wall of the annular groove, the first driving member comprises a driving ring, a driving gear and a driving motor, the driving ring is rotatably arranged in the annular groove, the mounting seat is fixedly arranged in the inner ring of the driving ring, the inner ring of the driving ring is provided with a toothed section, the toothed section is located on one side of the driving ring, the driving motor is embedded in the mounting plate, and the driving gear is arranged on the output shaft of the driving motor and is in meshing connection with the toothed section; the enclosing member further comprises a compensation member, which is used to drive the waterproof film wound on the winding shaft to abut against the boss during the wrapping of the waterproof film around the boss.

[0011] Optionally, the compensation member comprises a first spring and an extension tube, the mounting seat comprises a fixed seat and a sliding seat, the fixed seat is fixedly arranged on the inner side of the driving ring, the winding shaft is rotatably arranged on the side wall of the sliding seat, and the sliding seat is located on the fixed seat and is slidably arranged on the fixed seat; the extension tube is fixedly arranged between the fixed seat and the sliding seat, and the first spring is wrapped on the extension tube to drive the sliding seat to slide towards the boss to drive the waterproof film to abut against the boss.

[0012] Optionally, the enclosing member further comprises a sealing member, the sealing member comprises a glue applying roller, a glue applying groove and a second driving member, the glue applying groove is arranged on the sliding seat, the opening direction of the glue applying groove is towards the waterproof film, the glue applying roller is rotatably arranged in the glue applying groove and abuts against the outer side of the waterproof film, and the second driving member is used to drive the glue applying groove to move towards the winding shaft to make the glue applying roller abut against the outer side of the waterproof film.

[0013] Optionally, the glue applying roller crosses the end of the waterproof film on the winding shaft.

[0014] Optionally, the dehumidifying member comprises an air pipe and an air valve, the air pipe passes through the boss and the mounting plate and moves out of the prestressed beam along the direction of the prestressed tendon, the air valve is arranged on the air pipe, and the other end of the air pipe is used to be connected with a gas supply device to extract the humid air between the waterproof film and the boss and discharge the humid air through the air pipe.

[0015] Optionally, the dehumidifying member comprises an air pipe and an air valve, the air pipe passes through the boss and the mounting plate and extends out of the pre-stressed beam along the direction of the pre-stressed tendon, and the air valve is arranged on the air pipe, and the other end of the air pipe is connected with an air supply device to extract the humid air between the waterproof film and the boss and discharge the humid air through the air pipe.

[0016] Optionally, the measuring device further comprises a supporting net sleeved on the pre-stressed tendon, the supporting net is convex, and the strain gauge is located below the supporting net.

[0017] In a second aspect, the application provides a measuring method for measuring the effective pre-stress of a pre-stressed beam, and the method adopts the following technical scheme:

[0018] The measuring method for measuring the effective pre-stress of a pre-stressed beam uses the measuring device for measuring the effective pre-stress of a pre-stressed beam, and further comprises the following steps:

[0019] S1: when the pre-stressed tendon of the pre-stressed beam is built, the mounting plate and the boss are mounted on the pre-stressed tendon, the mounting plate and the boss are sleeved on the pre-stressed tendon, and the gap between the mounting plate, the boss and the pre-stressed tendon is sealed after the mounting plate and the boss are sleeved on the pre-stressed tendon;

[0020] S2: the strain gauge is fixed on the pre-stressed tendon, and the waterproof film is wound on the boss, and the waterproof film seals the strain gauge;

[0021] S3: the pre-stressed tendon is subjected to tensile stress, and the pre-stress is fed back through the resistance value of the strain gauge;

[0022] S4: when the waterproof film is damaged due to stretching or long-term use, the driving motor is started, the driving motor drives the driving gear and the driving ring to rotate, the driving ring drives the winding shaft to rotate, and the waterproof film is sleeved on the boss again to cover the damaged waterproof film again;

[0023] S5: when the waterproof film is covered again, the glue roller applies waterproof glue to the outer side of the waterproof film to seal and connect the adjacent layers of the waterproof film, and part of the glue penetrates to the inner side of the waterproof film through the edge of the waterproof film to seal the adjacent layers of the waterproof film.

[0024] The technical scheme of the application has at least the following advantages and beneficial effects:

[0025] 1. When measuring the effective stress on the prestressed tendon, the effective stress on the prestressed tendon is fed back through the resistance change of the strain gauge; after the strain gauge is fixedly installed on the prestressed tendon, the strain gauge is enclosed between two convex tables by the action of the enclosing member on the convex tables and is sealed between the convex tables and the enclosing member, thereby reducing the influence of the humid environment on the resistance value of the strain gauge and further improving the measurement accuracy of the prestress; at the same time, the strain gauge is sealed under the action of the enclosing member, compared with using clay or glue to separate the strain gauge from the humid environment, the influence of clay or glue on the deformation of the strain gauge is reduced, and the accuracy of the measured value is further improved; at the same time, when the strain gauge is connected to the current, the strain gauge will generate heat, if the strain gauge is separated from the environment by clay and the like, the heat generated by the strain gauge cannot be quickly conducted, and is easy to accumulate in the strain gauge and the clay, resulting in large strain gauge measurement error and clay cracking due to temperature rise, and the strain gauge and the environment cannot be well separated, under the action of the enclosing member, the strain gauge is separated from the environmental influence, and the strain gauge and the enclosing member are in a separated state, and the strain gauge is easy to quickly dissipate heat.

[0026] 2. After the enclosing member and the convex table enclose the strain gauge, the humid air in the enclosing member is extracted by the dehumidifying member, so that the space where the strain gauge is located is close to a vacuum state, further reducing the influence of environmental factors on the strain gauge, thereby improving the accuracy of the prestress measurement. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0028] Figure 1 is a whole structure schematic diagram of a measuring device for measuring the effective prestress of a prestressed beam according to an embodiment of the present application;

[0029] Figure 2 is a structure schematic diagram of an enclosing member in a measuring device for measuring the effective prestress of a prestressed beam according to an embodiment of the present application;

[0030] Figure 3 is a structure schematic diagram of a strain gauge in a measuring device for measuring the effective prestress of a prestressed beam according to an embodiment of the present application;

[0031] Figure 4 is a sectional view of a mounting plate and a convex table in a measuring device for measuring the effective prestress of a prestressed beam according to an embodiment of the present application.

[0032] The reference signs are explained as follows: 1, mounting plate; 2, boss; 3, strain gauge; 4, connecting wire;

[0033] 5, enclosing member; 51, winding shaft; 52, waterproof film; 53, driving ring; 54, driving gear; 55, driving motor; 56, toothed section; 57, first spring; 58, telescopic pipe; 59, glue roller; 510, glue groove; 511, second spring; 512, telescopic rod;

[0034] 6, dehumidifying member; 61, air pipe; 62, air valve;

[0035] 7, annular groove; 8, mounting seat; 81, fixed seat; 82, sliding seat; 9, sealing groove; 10, supporting net; 11, prestressed tendon. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0038] The following is further illustrated in conjunction with specific embodiments, referring to Figure 1 , Figure 2 and Figure 3 The measuring device for measuring the effective prestress of a prestressed beam comprises a mounting plate 1, a boss 2 and a strain gauge 3. The strain gauge 3 is fixed on the prestressed tendon 11. The mounting plate 1 is provided with two pieces and is fixedly arranged on the prestressed tendon 11. The strain gauge 3 is located between the two mounting plates 1. The boss 2 is fixedly arranged on the mounting plate 1 and faces the strain gauge 3. The connecting wire 4 of the strain gauge 3 passes through the boss 2 and the mounting plate 1 and then is led out from the prestressed beam along the running direction of the prestressed tendon 11.

[0039] Referring to Figure 2 , Figure 3 and Figure 4 The cross sections of the mounting plate 1 and the boss 2 are both circular. The measuring device further comprises an enclosing member 5. The enclosing member 5 is used to seal the strain gauge 3 between the boss 2 and the enclosing member 5 by surrounding the bosses 2 on both sides.

[0040] When the strain gauge 3 is fixedly installed on the prestressed tendon 11, the strain gauge 3 is enclosed between the two bosses 2 by the action of the enclosing member 5 on the bosses 2 and sealed between the bosses 2 and the enclosing member 5, thereby reducing the influence of the humid environment on the resistance value of the strain gauge 3, and further improving the measurement accuracy of the prestress; at the same time, the strain gauge 3 is sealed under the action of the enclosing member 5, compared with using clay or glue to separate the strain gauge 3 from the humid environment, the influence of the clay or glue on the deformation of the strain gauge 3 is reduced, and the accuracy of the measurement value is further improved; at the same time, when the strain gauge 3 is passed through the current, the strain gauge 3 will generate heat, if the strain gauge 3 is separated from the environment by clay and the like, the heat generated by the strain gauge 3 cannot be quickly conducted, and is easy to accumulate in the strain gauge 3 and the clay, resulting in a large measurement error of the strain gauge 3 and cracking of the clay due to the temperature rise, and the strain gauge 3 and the environment cannot be well separated, under the action of the enclosing member 5, the strain gauge 3 is separated from the environment, and the strain gauge 3 and the enclosing member 5 are in a separated state, and the strain gauge 3 is easy to quickly dissipate heat.

[0041] With reference to Figure 1 In order to further improve the measurement accuracy of the prestress, the measuring device further comprises a dehumidifying member 6, which is used to exhaust the humid air between the enclosing member 5 and the boss 2 to make the strain gauge 3 in a dry environment; after the enclosing member 5 and the boss 2 enclose the strain gauge 3, the humid air in the enclosing member 5 is extracted by the dehumidifying member 6, so that the space where the strain gauge 3 is located is close to a vacuum state, further reducing the influence of environmental factors on the strain gauge 3, thereby improving the accuracy of the measurement of the prestress.

[0042] With reference to Figure 3 And Figure 4 In the embodiment of the present application, the enclosing member 5 comprises a winding shaft 51, a waterproof film 52 and a first driving member, the length direction of the winding shaft 51 is parallel to the length direction of the prestressed tendon 11, the waterproof film 52 is wound on the winding shaft 51, the waterproof film 52 is wound with multiple layers, and the two ends of the winding shaft 51 are located on the two bosses 2 and span the strain gauge 3, and the first driving member is used to drive the winding shaft 51 to move around the boss 2 to drive the waterproof film 52 to surround and be sleeved on the boss 2 to seal the strain gauge 3;

[0043] With reference to Figure 3 And Figure 4The face of the mounting plate 1 towards the strain gauge 3 is provided with an annular groove 7, the boss 2 is fixedly arranged in the middle of the annular groove 7, both ends of the winding shaft 51 are provided with mounting seats 8, the winding shaft 51 is rotationally arranged on the mounting seat 8, the mounting seat 8 is slidingly arranged on the side wall of the annular groove 7, the first driving member comprises a driving ring 53, a driving gear 54 and a driving motor 55, the driving ring 53 is rotationally arranged in the annular groove 7, the mounting seat 8 is fixedly arranged in the inner ring of the driving ring 53, the inner ring of the driving ring 53 is provided with a toothed section 56, the toothed section 56 is located on one side of the driving ring 53, the driving motor 55 is embedded in the mounting plate 1, and the driving gear 54 is arranged on the output shaft of the driving motor 55 and is in meshing connection with the toothed section 56.

[0044] After the strain gauge 3 is fixed on the prestressed tendon 11, the driving motor 55 is started, the driving motor 55 drives the driving gear 54 to rotate, the driving gear 54 drives the driving ring 53 to rotate, the driving ring 53 drives the mounting seat 8 to rotate, the mounting seat 8 drives the winding shaft 51 to rotate around the circumference of the boss 2, and the winding shaft 51 drives the waterproof film 52 to surround the boss 2 when rotating, so that the strain gauge 3 is sealed in the boss 2 and the waterproof film 52, and the operation is simple and convenient; further, since the waterproof film 52 is sleeved on the boss 2, the waterproof film 52 is in a separated state from the strain gauge 3, so that the influence of the waterproof film 52 on the strain gauge 3 is reduced; further, when the surrounded waterproof film 52 is locally damaged, the driving motor 55 drives the winding shaft 51 to rotate to surround the waterproof film 52 on the boss 2 again, so as to cover the damaged waterproof film 52, thereby restoring the sealing performance of the waterproof film 52.

[0045] With reference to Figure 3 and Figure 4, with the waterproof film 52 sleeved on the boss 2, the waterproof film 52 on the winding shaft 51 gradually reduces in thickness, causing the outermost waterproof film 52 to be difficult to abut on the boss 2, thereby causing a large gap between the waterproof films 52 of adjacent layers, and causing the sealing performance of the waterproof film 52 to be general, therefore in the embodiment of the application, the enclosing member 5 further comprises a compensation member, the compensation member being used to drive the waterproof film 52 wound on the winding shaft 51 to abut on the boss 2 during the waterproof film 52 being sleeved on the boss 2, the compensation member comprising a first spring 57 and an extension tube 58, the mounting seat 8 comprising a fixed seat 81 and a sliding seat 82, the fixed seat 81 being fixedly arranged inside the driving ring 53, the winding shaft 51 being rotatably arranged on the side wall of the sliding seat 82, the sliding seat 82 being located on the fixed seat 81 and slidably arranged on the fixed seat 81, the sliding seat 82 sliding in a direction perpendicular to the fixed seat 81, the extension tube 58 being fixedly arranged between the fixed seat 81 and the sliding seat 82, the first spring 57 being sleeved on the extension tube 58 and used to drive the sliding seat 82 to slide towards the boss 2 to drive the waterproof film 52 to abut on the boss 2; when the driving ring 53 drives the winding shaft 51 to sleeve the waterproof film 52 on the boss 2, with the waterproof film 52 on the winding shaft 51 gradually reducing in thickness, under the action of the first spring 57, the sliding seat 82 is driven to move towards the winding shaft 51, the sliding seat 82 drives the winding shaft 51 and the waterproof film 52 to move close to the boss 2, so that the waterproof film 52 abuts on the outside of the boss 2, thereby improving the sealing performance of the waterproof film 52.

[0046] With reference to Figure 3 and Figure 4 , the waterproof film 52 only surrounds and sleeves the boss 2, causing the sealing performance between the waterproof films 52 of adjacent layers to be general, in order to improve the sealing performance between the waterproof films 52 of adjacent layers, the enclosing member 5 further comprises a sealing member, the sealing member comprising a glue applying roller 59, a glue applying groove 510 and a second driving member, the glue applying groove 510 being arranged on the sliding seat 82, the opening direction of the glue applying groove 510 facing the waterproof film 52, the glue applying roller 59 being rotatably arranged in the glue applying groove 510 and abutting on the outside of the waterproof film 52, further, the glue applying groove 510 is slidably arranged on the side wall of the sliding seat 82, the glue applying groove 510 sliding in a direction perpendicular to the winding shaft 51, the second driving member being used to drive the glue applying groove 510 to move towards the winding shaft 51 so that the glue applying roller 59 abuts on the outside of the waterproof film 52, the second driving member comprising a second spring 511, one end of the second spring 511 being fixedly arranged inside the driving ring 53, the other end being fixedly arranged on the bottom of the glue applying groove 510, further, the second driving member further comprises an extension rod 512 arranged between the driving ring 53 and the glue applying groove 510.

[0047] When the driving ring 53 drives the winding shaft 51 to rotate around the boss 2, the waterproof film 52 is wrapped around the boss 2, and in this process, the glue groove 510 is driven to move the glue roller 59 towards the waterproof film 52 under the action of the second spring 511, so that the glue roller 59 abuts on the outer side of the waterproof film 52, and the glue roller 59 rotates to apply glue on the waterproof film 52 in this process. After the outer waterproof film 52 is covered on the inner waterproof film 52, the outer waterproof film 52 is pasted on the inner waterproof film 52, thereby improving the sealing performance of the adjacent layers of waterproof film 52.

[0048] With reference to Figure 3 And Figure 4 To further improve the sealing performance of the waterproof film 52, the glue roller 59 spans the end of the waterproof film 52 on the winding shaft 51; after the glue roller 59 applies waterproof glue, the glue on the edge of the waterproof film 52 flows over the end of the waterproof film 52 to the inner side of the waterproof film 52 to seal and bond the inner and outer sides of the waterproof film 52.

[0049] The glue on the edge of the waterproof film 52 flows towards the lateral end of the waterproof film 52 under the action of the pressure joint, and flows to the inner side of the waterproof film 52 to seal and bond the inner and outer sides of the waterproof film 52.

[0050] With reference to Figure 1 In the embodiment of the application, the dehumidifying member 6 includes an air pipe 61 and an air valve 62, the air pipe 61 passes through the boss 2 and the mounting plate 1 and moves out of the prestressed beam along the direction of the prestressed tendon 11, the air valve 62 is arranged on the air pipe 61, and the other end of the air pipe 61 is used to connect an air supply device to extract the humid air between the waterproof film 52 and the boss 2 and discharge the humid air through the air pipe 61; after the waterproof film 52 is sleeved on the boss 2, the air pipe 61 is connected to the air supply device, and the humid air in the waterproof film 52 is extracted through the air supply device, so that the strain gauge 3 is in a dry environment, and the operation is simple and convenient; at the same time, after the humid air in the waterproof film 52 is extracted, dry air is injected into the waterproof film 52 through the air supply device to replace the humid air, thereby further improving the test accuracy of the prestress and prolonging the service life of the strain gauge 3.

[0051] With reference to Figure 3 And Figure 4In the embodiment of the present application, in order to improve the sealing between the innermost waterproof film 52 and the boss 2, a sealing groove 9 is arranged on the outer ring of the boss 2, the sealing groove 9 is connected in a ring shape, a connecting channel is arranged in the boss 2, the connecting channel is used to connect the sealing groove 9 and the air pipe 61, and when the humid air is extracted by the air supply device, the air in the sealing groove 9 is extracted to suck the waterproof film 52 into the sealing groove 9; after the waterproof film 52 is sleeved on the boss 2, the humid air is extracted by the air supply device, at this time, the air in the sealing groove 9 is extracted, so that the innermost waterproof film 52 moves towards the sealing groove 9, thereby improving the sealing between the waterproof film 52 and the boss 2.

[0052] Referring to Figure 2 and Figure 3 When the humid gas in the waterproof film 52 is extracted, the waterproof film 52 has a tendency to be concave towards the prestressed tendon 11 and is crimped on the strain gauge 3, which hinders the deformation of the strain gauge 3, therefore, in the embodiment of the present application, the measuring device further comprises a supporting net 10 sleeved on the prestressed tendon 11, the supporting net 10 is convex, and the strain gauge 3 is located below the supporting net 10; under the action of the supporting net 10, the waterproof film 52 and the strain gauge 3 are separated, thereby reducing the hindering of the waterproof film 52 to the strain gauge 3 and improving the accuracy of the prestress measurement data.

[0053] The implementation principle of the measuring device for measuring the effective prestress of the prestressed beam in the embodiment of the present application is as follows:

[0054] When the strain gauge 3 is fixedly installed on the prestressed tendon 11, the strain gauge 3 is enclosed between the two bosses 2 by the action of the enclosing member 5 on the boss 2 and is sealed between the boss 2 and the enclosing member 5, thereby reducing the influence of the humid environment on the resistance value of the strain gauge 3 and further improving the measurement accuracy of the prestress; at the same time, the strain gauge 3 is sealed under the action of the enclosing member 5, compared with using clay or glue to separate the strain gauge 3 from the humid environment, the influence of the clay or glue on the deformation of the strain gauge 3 is reduced, and the accuracy of the measurement value is further improved; at the same time, when the strain gauge 3 is electrified, the strain gauge 3 generates heat, if the strain gauge 3 is separated from the environment by using clay and the like, the heat generated by the strain gauge 3 cannot be quickly conducted and is easy to accumulate in the strain gauge 3 and the clay, which leads to a large measurement error of the strain gauge 3 and cracking of the clay due to temperature rise, and the strain gauge 3 cannot be well separated from the environment, under the action of the enclosing member 5, the strain gauge 3 is separated from the environment, and the strain gauge 3 and the enclosing member 5 are in a separated state, which is convenient for rapid heat dissipation of the strain gauge 3.

[0055] The embodiment of the present application discloses a measuring method for measuring the effective prestress of a prestressed beam, using a measuring device for measuring the effective prestress of a prestressed beam, and further comprising;

[0056] S1: when the prestressed tendon 11 of the prestressed beam is built, the mounting plate 1 and the boss 2 are installed on the prestressed tendon 11, the mounting plate 1 and the boss 2 are installed by penetrating the prestressed tendon 11, and after the mounting plate 1 and the boss 2 are sleeved on the prestressed tendon 11, the gap between the mounting plate 1 and the boss 2 and the prestressed tendon 11 is sealed;

[0057] S2: the strain gauge 3 is fixed on the prestressed tendon 11, and the waterproof film 52 is wound on the boss 2, and the waterproof film 52 is sealed by surrounding the strain gauge 3;

[0058] S3: the prestressed tendon 11 is applied with tensile stress, and the prestress is fed back through the resistance value of the strain gauge 3;

[0059] S4: when the waterproof film 52 is damaged due to stretching or long-term use, the driving motor 55 is started, the driving motor 55 drives the driving gear 54 and the driving ring 53 to rotate, the driving ring 53 drives the winding shaft 51 to rotate, and the waterproof film 52 is sleeved on the boss 2 again, so as to cover the damaged waterproof film 52 again;

[0060] S5: when the waterproof film 52 is covered again, the glue roller 59 applies waterproof glue to the outside of the waterproof film 52, so as to seal and connect the adjacent layers of the waterproof film 52, and part of the glue penetrates to the inside of the waterproof film 52 through the edge of the waterproof film 52, so as to seal the adjacent layers of the waterproof film 52.

[0061] The above are preferred embodiments of the application, and do not limit the protection scope of the application, so that: any equivalent changes made according to the structure, shape, principle of the application should be covered in the protection scope of the application.

Claims

1. A measuring device for measuring the effective prestress of a prestressed beam, characterized in that: The measuring device comprises a mounting plate (1), a boss (2) and a strain gauge (3), the strain gauge (3) is fixed on a prestressed tendon (11), the mounting plate (1) is provided with two and fixedly arranged on the prestressed tendon (11), the strain gauge (3) is located between the two mounting plates (1), the boss (2) is fixedly arranged on the mounting plate (1) and faces the strain gauge (3), the connecting lead (4) of the strain gauge (3) passes through the boss (2) and the mounting plate (1) and then is drawn out from the prestressed beam along the direction of the prestressed tendon (11); The cross sections of the mounting plate (1) and the boss (2) are circular, the measuring device further comprises a surrounding member (5) for sealing the strain gauge (3) between the boss (2) and the surrounding member (5) by surrounding the bosses (2) on both sides; The measuring device further comprises a dehumidifying member (6) for discharging the humid air between the surrounding member (5) and the boss (2) to make the strain gauge (3) in a dry environment; The surrounding member (5) comprises a winding shaft (51), a waterproof film (52) and a first driving member, the length direction of the winding shaft (51) is parallel to the length direction of the prestressed tendon (11), the waterproof film (52) is wound on the winding shaft (51), the two ends of the winding shaft (51) are located on the two bosses (2) and cross the strain gauge (3), and the first driving member is used to drive the winding shaft (51) to move around the boss (2) to drive the waterproof film (52) to surround and be sleeved on the boss (2) to seal the strain gauge (3); The dehumidifying member (6) comprises an air pipe (61) and an air valve (62), the air pipe (61) passes through the boss (2) and the mounting plate (1) and is drawn out from the prestressed beam along the direction of the prestressed tendon (11), the air valve (62) is arranged on the air pipe (61), and the other end of the air pipe (61) is used to be connected with a gas supply device to extract the humid air between the waterproof film (52) and the boss (2) and discharge the humid air through the air pipe (61); The outer ring of the boss (2) is provided with a sealing groove (9), the sealing groove (9) is connected in a ring shape, a connecting channel is arranged in the boss (2), the connecting channel is used to connect the sealing groove (9) and the air pipe (61), and when the gas supply device extracts the humid air, the gas in the sealing groove (9) is extracted to suck the waterproof film (52) into the sealing groove (9); The measuring device further comprises a supporting net (10) sleeved on the prestressed tendon (11), the supporting net (10) is convex, and the strain gauge (3) is located below the supporting net (10).

2. The measuring device for measuring effective prestress of a prestressed beam according to claim 1, characterized in that: The mounting plate (1) is provided with an annular groove (7) on the surface facing the strain gauge (3), the boss (2) is fixedly arranged in the middle of the annular groove (7), both ends of the winding shaft (51) are provided with mounting seats (8), the winding shaft (51) is rotatably arranged on the mounting seat (8), the mounting seat (8) is slidably arranged on the side wall of the annular groove (7), the first driving member comprises a driving ring (53), a driving gear (54) and a driving motor (55), the driving ring (53) is rotatably arranged in the annular groove (7), the mounting seat (8) is fixedly arranged in the inner ring of the driving ring (53), the inner ring of the driving ring (53) is provided with a toothed section (56), the toothed section (56) is located on one side of the driving ring (53), the driving motor (55) is embedded in the mounting plate (1), and the driving gear (54) is arranged on the output shaft of the driving motor (55) and is in meshing connection with the toothed section (56); the enclosing member (5) further comprises a compensation member, which is used to drive the waterproof film (52) wound on the winding shaft (51) to abut against the boss (2) during sleeving of the waterproof film (52) on the boss (2).

3. The measuring device for measuring effective prestress of a prestressed beam according to claim 2, characterized in that: The compensation member comprises a first spring (57) and a telescopic pipe (58), the mounting seat (8) comprises a fixed seat (81) and a sliding seat (82), the fixed seat (81) is fixedly arranged on the inner side of the driving ring (53), the winding shaft (51) is rotatably arranged on the side wall of the sliding seat (82), the sliding seat (82) is located on the fixed seat (81) and is slidably arranged on the fixed seat (81), the telescopic pipe (58) is fixedly arranged between the fixed seat (81) and the sliding seat (82), and the first spring (57) is sleeved on the telescopic pipe (58) and is used to drive the sliding seat (82) to slide towards the boss (2) to drive the waterproof film (52) to abut against the boss (2).

4. The measuring device for measuring effective prestress of a prestressed beam according to claim 3, characterized in that: The enclosing member (5) further comprises a sealing member, the sealing member comprises a glue coating roller (59), a glue coating groove (510) and a second driving member, the glue coating groove (510) is arranged on the sliding seat (82), the opening direction of the glue coating groove (510) faces the waterproof film (52), the glue coating roller (59) is rotatably arranged in the glue coating groove (510) and abuts against the outer side of the waterproof film (52), and the second driving member is used to drive the glue coating groove (510) to move towards the winding shaft (51) so that the glue coating roller (59) abuts against the outer side of the waterproof film (52).

5. The device for measuring the effective prestress of a prestressed beam according to claim 4, characterized in that: The glue coating roller (59) spans the end of the waterproof film (52) on the winding shaft (51).

6. A method of measuring the effective prestress of a prestressed beam using the measuring device for measuring the effective prestress of a prestressed beam according to any one of claims 1 to 5, characterized by: Further comprising; S1: when the prestressed tendon (11) of the prestressed beam is built, the mounting plate (1) and the boss (2) are installed on the prestressed tendon (11), when the mounting plate (1) and the boss (2) are installed, the mounting plate (1) and the boss (2) pass through the prestressed tendon (11), after the mounting plate (1) and the boss (2) are sleeved on the prestressed tendon (11), the gap between the mounting plate (1), the boss (2) and the prestressed tendon (11) is sealed; S2: The strain gauge (3) is fixed on the prestressed tendon (11) and wrapped on the boss (2) through the waterproof film (52), which encloses and seals the strain gauge (3); S3: The prestressed tendon (11) is subjected to tensile stress, and the prestress is fed back through the resistance value of the strain gauge (3); S4: When the waterproof film (52) is damaged due to stretching or long-term use, the driving motor (55) is started, the driving motor (55) drives the driving gear (54) and the driving ring (53) to rotate, the driving ring (53) drives the winding shaft (51) to rotate to wrap the waterproof film (52) on the boss (2) again, so as to cover the damaged waterproof film (52) again; S5: When the waterproof film (52) is covered again, the glue roller (59) applies waterproof glue to the outer side of the waterproof film (52) to seal and connect the adjacent layers of the waterproof film (52), and part of the glue penetrates to the inner side of the waterproof film (52) through the edge of the waterproof film (52) to seal the adjacent layers of the waterproof film (52).

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