Precast beam prestressed tendon tensioning device and tensioning method thereof

Abstract

The invention relates to a tensioning device for prestressed tendons of a precast beam and a tensioning method of the tensioning device. The tensioning device is used for solving the technical problems that when multiple prestressed tendons are tensioned, due to diameter deviation, the tightness degree is different, and even the tendons are broken. The device comprises a tensioning hydraulic system and a pressure control valve, wherein the pressure control valve comprises a valve element capable of controlling the hydraulic pressure of the tensioning hydraulic system; the front end of the telescopic rod is connected with the anchor plate through a connecting sleeve, the length of the clamping piece is larger than the depth of the taper hole, the length, extending out of the anchor plate, of the clamping piece is increased along with the increase of the diameter of the prestressed tendon to be tensioned, the length, extending out of the anchor plate, of the clamping piece is in direct proportion correlation with the displacement amount of the valve element, and the displacement amount of the valve element is increased along with the increase of the length, extending out of the taper hole, of the clamping piece. And the internal through-flow sectional area of the pressure control valve controlled by the valve core is reduced, so that the diameter of the prestressed tendon to be tensioned is inversely proportional to the hydraulic pressure of the tensioning hydraulic system.

Description

Technical Field

[0001] The present invention relates to a tensioning device for prestressed tendons of precast beams and a tensioning method therefor. Background Art

[0002] Prestressed tendons are special steel bars that are prestressed in advance by a certain external force to increase the compressive strength of concrete components. Generally, the prestressed tendons are tensioned before pouring the concrete. In the traditional tensioning method, anchor devices are generally arranged at both ends of the prestressed tendons. One end is fixed, and the other end uses a hydraulic cylinder or a jack to tension the prestressed tendons. After reaching the design stress value, the jack is slowly released, and the wedge jaws of the anchor device are brought into the tapered holes of the anchor plate by the steel strand bundle moving back uniformly. Thus, an anchoring unit is formed, and the stress of the steel strand bundle is transmitted to the building structure through the anchor plate and the anchor backing plate to form a permanent prestress.

[0003] However, when tensioning multiple prestressed tendons in the traditional tensioning method, the tightness difference is often caused by some factors, leading to local stress concentration and causing wire breakage. Among them, the wire breakage caused by the diameter deviation of the prestressed tendons accounts for an important part, because there is an allowable deviation in the diameter of the prestressed tendons. For example, the allowable error of the diameter of ordinary high-strength steel bars is plus or minus 0.3 mm, and the allowable error of the diameter of rolled steel bars is plus or minus 0.2 mm.

[0004] Therefore, it will be of great significance to solve the problem of wire breakage caused by the inconsistent tightness of the prestressed tendon tensioning due to the diameter deviation of the prestressed tendons. Summary of the Invention

[0005] The purpose of the present invention is to provide a tensioning device for prestressed tendons of precast beams to solve the technical problem of different tightness and even wire breakage caused by diameter deviation when tensioning multiple prestressed tendons. The purpose of the present invention is also to provide a tensioning method for prestressed tendons of precast beams using the above-mentioned tensioning device for prestressed tendons of precast beams.

[0006] The technical solution of the tensioning device for prestressed tendons of precast beams of the present invention is as follows: The tensioning device for prestressed tendons of precast beams includes: A tensioning hydraulic system, the tensioning hydraulic system includes a hydraulic cylinder. The hydraulic cylinder includes a telescopic rod. The front end of the telescopic rod is connected to the prestressed tendon to be tensioned through a tensioning anchor device. The tensioning anchor device includes an anchor plate and wedge jaws. The anchor plate is provided with a tapered hole. The wedge jaws are composed of multiple pieces and have a cylindrical inner part and a tapered outer part. One end of the prestressed tendon to be tensioned is wedged tightly in the tapered hole through the wedge jaws. The anchor plate is connected to the front end of the telescopic rod; Pressure control valve, including a valve core that can control the hydraulic pressure of the tensioning hydraulic system; the front end of the telescopic rod is connected to the anchor plate through a connecting sleeve. The length of the wedge is greater than the depth of the tapered hole. The length of the wedge extending out of the anchor plate increases with the increase in the diameter of the prestressed tendon to be tensioned. The length of the wedge extending out of the anchor plate is in a proportional relationship with the displacement of the valve core. As the length of the wedge extending out of the tapered hole increases, the internal flow cross-sectional area of the pressure control valve controlled by the valve core decreases, so that the diameter of the prestressed tendon to be tensioned is inversely proportional to the hydraulic pressure of the tensioning hydraulic system.

[0007] The beneficial effects of this technical solution are as follows: Compared with the prior art, the tensioning device of this application ingeniously reflects the diameter error of the prestressed tendon in the axial displacement of the wedge of the tensioning anchor. By directly correlating the axial displacement of the wedge with the pressure control valve of the tensioning hydraulic system in proportion, it is possible to adaptively change the corresponding hydraulic pressure according to the diameter error of the prestressed tendon without measuring the diameter error of the prestressed tendon, that is, to achieve the purpose of self-adjustment, eliminate the tightness difference caused by the diameter error of the prestressed tendon, and further avoid the local stress concentration of the prestressed tendon and cause wire breakage.

[0008] On the basis of the above solution, the further improvement is as follows: The wedge is connected to the valve core through mechanical components, so that the valve core moves with the axial movement of the wedge.

[0009] The beneficial effects of this technical solution are as follows: The method of directly transmitting displacement through mechanical components for adaptive adjustment has the advantages of stable and reliable transmission, direct transmission, few intermediate links, small error, simple structure, and low cost compared with the electronic method.

[0010] On the basis of the above solution, the further improvement is as follows: A sliding sleeve for sleeving on the prestressed tendon is connected to the outer end of the wedge. A force transmission rod is provided radially on the sliding sleeve. The pressure control valve includes a valve body. A sliding hole is provided on the valve body. One end of the valve core is slidably and hermetically assembled at the sliding hole and extends outside the sliding hole. The other end of the force transmission rod is in abutting cooperation with the valve core to transmit displacement.

[0011] The beneficial effects of this technical solution are as follows: By sleeving the sliding sleeve on the prestressed tendon and directly contacting the wedge, under the guidance of the prestressed tendon, the displacement of the wedge can be directly transmitted to the force transmission rod. This structure is simple, direct, effective, and has a low cost.

[0012] On the basis of the above solution, the further improvement is as follows: A spring is provided in the valve body, and the spring provides an elastic acting force to the valve core in the direction of squeezing the force transmission rod.

[0013] The beneficial effects of this technical solution are as follows: The spring is provided, so that the valve core and the force transmission rod do not need to be mechanically connected, and only need to be abutted and matched. The spring force can make the valve core and the force transmission rod synchronous. In addition, the spring also has a buffering effect, which can avoid accidental impacts, protect the valve core, and ensure the stability of the system pressure.

[0014] On the basis of the above solution, the further improvement is as follows: The pressure control valve is a flow control valve, and its valve body is provided with a first interface and a second interface that are communicated with each other. The valve body is connected in series to the main oil path of the tensioning hydraulic system through the first interface and the second interface. The valve core moves along the radial direction of the valve body to change the flow cross-sectional area of the internal channel of the valve body.

[0015] On the basis of the above solution, the further improvement is as follows: The connecting sleeve is provided with an avoidance long hole corresponding to the force transmission rod. The length of the avoidance long hole extends along the axial direction of the sliding sleeve. The force transmission rod can slide along the length direction of the avoidance long hole. While the prestressed tendon guides the sliding sleeve, the force transmission rod can be accurately docked with the valve core at the other end under the guiding action of the avoidance long hole to transfer the displacement to the valve core.

[0016] On the basis of the above solution, the further improvement is as follows: An annular boss is provided on the inner peripheral surface of the connecting sleeve, and the connecting sleeve is hooked and matched with the anchor plate through the annular boss.

[0017] On the basis of the above solution, the further improvement is as follows: A conical channel is provided on the internal channel of the valve body, and a conical platform is correspondingly provided at the inner end of the valve core. The adjustment of the flow cross-section is realized through the cooperation of the conical platform and the conical channel.

[0018] The technical solution of the tensioning method of the precast beam prestressed tendon tensioning device of the present invention is as follows: It includes the following steps: The two ends of the prestressed tendon are respectively sleeved into a pair of symmetrically arranged positioning anchor devices, and the end of the prestressed tendon to be tensioned is sleeved into the tensioning anchor device. Make the length of the clamping piece of the tensioning anchor device extending out of the anchor plate be in a proportional relationship with the displacement of the valve core of the pressure control valve, so that as the length of the clamping piece extending out of the tapered hole of the anchor plate increases, the internal flow cross-sectional area of the pressure control valve controlled by the valve core decreases, so that the diameter of the prestressed tendon is inversely proportional to the hydraulic pressure of the tensioning hydraulic system. The tensioning hydraulic system can change the corresponding hydraulic pressure with the change of the diameter of the prestressed tendon and the relationship between the length of the clamping piece extending out of the anchor plate and the displacement of the valve core.

[0019] On the basis of the above solution, the further improvement is as follows: At least two sets of hydraulic cylinders with the same size are used in parallel. Correspondingly, at least two groups of tensioning pedestals corresponding to the positioning anchor devices are used in parallel. Description of the Drawings

[0020] Figure 1Structural schematic diagram of Embodiment 1 of the precast beam prestressed tendon tensioning device of the present invention; Figure 2 is Figure 1 Partial enlarged view at A in Figure 3 is Figure 1 Partial enlarged view at B in Figure 4 is Figure 3 Variation state diagram of the wedge-shaped grip and the sliding sleeve corresponding to an increase in the diameter of the prestressed tendon; Figure 5 is Figure 3 Side view of the corresponding connection sleeve; Figure 6 Structural schematic diagram of Embodiment 2 of the precast beam prestressed tendon tensioning device of the present invention; Figure 7 Structural schematic diagram of Embodiment 3 of the precast beam prestressed tendon tensioning device of the present invention; In the figure: 1 - prestressed tendon, 2 - tensioning hydraulic system, 21 - hydraulic pump, 22 - motor, 23 - controller, 24 - hydraulic oil tank, 25 - safety valve, 26 - electromagnetic switching valve, 27 - hydraulic cylinder, 271 - cylinder block, 272 - piston, 273 - telescopic rod, 28 - tensioning anchor, 281 - anchor plate, 2811 - tapered hole, 282 - wedge-shaped grip, 29 - connection sleeve, 291 - avoidance long hole, 292 - annular boss, 3 - pressure control valve, 31 - valve body, 311 - sliding hole, 312 - star seal, 313 - tapered channel, 314 - first interface, 315 - second interface, 32 - valve core, 321 - tapered platform, 322 - installation groove, 4 - sliding sleeve, 41 - force transmission rod, 411 - abutting disc, 5 - spring, 6 - tensioning pedestal, 61 - positioning anchor. Detailed implementation manners

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0022] Therefore, the detailed description of the embodiments of the present invention provided in the drawings below is not intended to limit the scope of the claimed present invention, but only represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

[0023] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0024] The features and performance of the present invention will be further described in detail below in conjunction with embodiments.

[0025] Embodiment 1 of the precast beam prestressing tendon tensioning device of the present invention: As Figure 1 shown, the precast beam prestressing tendon tensioning device mainly includes a tensioning hydraulic system 2, a pressure control valve 3, a tensioning pedestal 6, etc. The tensioning pedestal 6 includes two longitudinal beams arranged in parallel and two cross beams arranged in parallel. A pair of positioning anchors 61 are respectively provided on the two cross beams corresponding to each prestressing tendon 1. The positioning anchor is a prior art and includes an anchor plate, wedge-shaped jaws, a backing plate, and a spiral rib.

[0026] As Figure 1 shown, the tensioning hydraulic system 2 includes a motor and a hydraulic pump 21 driven by the motor, a controller 23, a hydraulic oil tank 24, a safety valve 25, an electromagnetic switching valve 26, a hydraulic cylinder 27, etc. The hydraulic cylinder 27 includes a cylinder block 271. Inlets and outlets are respectively provided at both ends of the cylinder block 271. A piston 272 and a telescopic rod 273 are provided in the cylinder block 271. One end of the telescopic rod 273 can slide out of the cylinder block 271 through a Step seal 312 provided on the cylinder block 271. The front end of the telescopic rod 273 is connected to the prestressing tendon 1 to be tensioned through a tensioning anchor 28. The tensioning anchor 28 includes an anchor plate 281 and wedge-shaped jaws 282. A tapered hole 2811 is provided on the anchor plate 281. The wedge-shaped jaws 282 are a structure formed by splicing multiple pieces, with a cylindrical interior and a tapered exterior. One end of the prestressing tendon 1 to be tensioned is wedged tightly in the tapered hole 2811 through the wedge-shaped jaws 282. The anchor plate 281 is connected to the front end of the telescopic rod 273. As Figures 2-4As shown in the figure, in this embodiment, the jaw 282 and the valve core 32 are connected by mechanical components, so that the valve core 32 moves with the axial movement of the jaw 282. The way of directly transmitting displacement by mechanical components for adaptive adjustment has the advantages of stable and reliable transmission, direct transmission, few intermediate links, small error, simple structure and low cost compared with the electronic way. Specifically, a sliding sleeve 4 for sleeving on the prestressed tendon 1 is connected to the outer end of the jaw 282. A force transmission rod 41 is arranged radially on the sliding sleeve 4. The pressure control valve 3 includes a valve body 31, and a sliding hole 311 is arranged on the valve body 31. One end of the valve core 32 is slidably and sealingly assembled at the sliding hole 311 and extends outside the sliding hole 311. The other end of the force transmission rod 41 abuts against the valve core 32 to transmit displacement. By sleeving the sliding sleeve 4 on the prestressed tendon 1 and directly contacting the jaw 282, under the guidance of the prestressed tendon 1, the displacement of the jaw 282 can be directly transmitted to the force transmission rod 41. This structure is simple, direct and effective, and the cost is relatively low. A relief long hole 291 corresponding to the force transmission rod 41 is arranged on the connecting sleeve 29. The length of the relief long hole 291 extends along the axial direction of the sliding sleeve 4. The force transmission rod 41 can slide along the length direction of the relief long hole 291. While the prestressed tendon 1 guides the sliding sleeve 4, the force transmission rod 41 can be accurately docked with the valve core 32 at its other end under the guiding action of the relief long hole 291 to transmit the displacement to the valve core 32. An annular boss 292 is arranged on the inner peripheral surface of the connecting sleeve 29. The connecting sleeve 29 is hooked and matched with the anchor plate 281 through the annular boss 292.

[0027] In other embodiments, the jaw 282 and the valve core 32 can also be associated by electronic components. For example, the displacement of the jaw 282 is detected by a displacement sensor and fed back to the controller. The controller controls the rotation angle of the motor and then controls the movement distance of the linear motion mechanism driven by the motor, and the linear motion mechanism drives the valve core 32 to displace.

[0028] As part of the tensioning hydraulic system 2, the pressure control valve 3 includes a valve core 32 that can control the hydraulic pressure of the tensioning hydraulic system 2. A spring 5 is provided inside the valve body 31. The spring 5 provides an elastic acting force to the valve core 32 in the direction of pressing against the force transfer rod 41. The setting of the spring 5 enables the valve core 32 and the force transfer rod 41 to be synchronized by relying on the acting force of the spring 5 without the need for mechanical connection, only by abutting and cooperating. In addition, the spring 5 also has a buffering effect, which can avoid accidental impacts, protect the valve core 32, and ensure the stability of the system pressure. The pressure control valve 3 is a flow control valve. The valve body 31 is provided with a first interface 314 and a second interface 315 that are interconnected. The valve body 31 is connected in series to the main oil path of the tensioning hydraulic system 2 through the first interface 314 and the second interface 315. The valve core 32 moves radially along the valve body 31 to change the flow cross-sectional area of the internal passage of the valve body 31. A conical passage 313 is provided in the internal passage of the valve body 31. The inner end of the valve core 32 is correspondingly provided with a conical platform 321. The adjustment of the flow cross-section is achieved through the cooperation of the conical platform 321 and the conical passage 313. The front end of the telescopic rod 273 is connected to the anchor plate 281 through a connecting sleeve 29. In this application, the structure of the wedge-shaped clamp 282 is different from that of the wedge-shaped clamp 282 of the traditional anchor. The length of the wedge-shaped clamp 282 in this application is greater than the depth of the tapered hole 2811, so as to better associate its axial displacement with the displacement of the valve core 32. The length of the wedge-shaped clamp 282 extending out of the anchor plate increases with the increase in the diameter of the prestressed tendon 1 to be tensioned. The length of the wedge-shaped clamp 282 extending out of the anchor plate is in a proportional relationship with the displacement amount of the valve core 32. As the length of the wedge-shaped clamp 282 extending out of the tapered hole 2811 increases, the internal flow cross-sectional area of the pressure control valve 3 controlled by the valve core 32 decreases, so that the diameter of the prestressed tendon 1 to be tensioned is inversely proportional to the hydraulic pressure of the tensioning hydraulic system 2.

[0029] In other embodiments, the pressure control valve 3 can also choose the following methods to control the hydraulic pressure of the tensioning hydraulic system, such as adjustable pressure relief valves, proportional control valves, digital valves, etc.

[0030] Compared with the prior art, the tensioning device of this application cleverly reflects the diameter error of the prestressed tendon 1 in the axial displacement of the wedge-shaped clamp 282 of the tensioning anchor 28. By directly associating the axial displacement of the wedge-shaped clamp 282 with the pressure control valve 3 of the tensioning hydraulic system 2 in a proportional relationship, it is possible to adaptively change the corresponding hydraulic pressure according to the diameter error of the prestressed tendon 1 without measuring the diameter error of the prestressed tendon 1, that is, to achieve the purpose of self-adjustment, eliminate the tightness difference caused by the diameter error of the prestressed tendon 1, and further avoid the local stress concentration of the prestressed tendon 1 resulting in wire breakage.

[0031] Embodiment 2 of the precast beam prestressed tendon tensioning device of the present invention: As Figure 6As shown, the difference from Embodiment 1 is that the number of the tensioning hydraulic system 2 and the tensioning pedestal is two sets, and the two sets have the same shape and size, and are arranged side by side in parallel or detachably connected into one body by a mechanical connection method.

[0032] Embodiment 3 of the tensioning device for prestressed tendons of precast beams of the present invention: As Figure 7 shown, the difference from Embodiment 1 is that the number of the tensioning hydraulic system 2 and the tensioning pedestal is two sets, the two sets have the same shape and size, and the two sets of hydraulic cylinders 27 share the cylinder block 271, and the two sets of tensioning pedestals share the cross beam and the longitudinal beam, and their consistency is higher.

[0033] Specific embodiments of the tensioning method of the tensioning device for prestressed tendons of precast beams of the present invention: The following steps are included: The two ends of the prestressed tendon 1 are respectively sleeved into a pair of symmetrically arranged positioning anchors, and the end of the prestressed tendon 1 to be tensioned is sleeved into the tensioning anchor 28. Make the length of the wedge 282 of the tensioning anchor 28 extending out of the anchor plate be in a proportional relationship with the displacement of the valve core 32 of the pressure control valve 3, so that as the length of the wedge 282 extending into the tapered hole 2811 of the anchor plate 281 increases, the internal flow cross-sectional area of the pressure control valve 3 controlled by the valve core 32 decreases, so that the diameter of the prestressed tendon 1 is inversely proportional to the hydraulic pressure of the tensioning hydraulic system 2, and the tensioning hydraulic system 2 can change the corresponding hydraulic pressure according to the change of the diameter of the prestressed tendon 1 and the relationship between the length of the wedge 282 extending out of the anchor plate and the displacement of the valve core 32.

[0034] In other embodiments, at least two sets of hydraulic cylinders 27 with the same size are used in parallel, and correspondingly, at least two groups of tensioning pedestals corresponding to the positioning anchors are used in parallel.

[0035] As mentioned above, only the preferred embodiments of the present invention are provided, and they are not intended to limit the present invention. The patent protection scope of the present invention is subject to the claims. Any equivalent structural changes made by using the description and drawings of the present invention should be included in the protection scope of the present invention by the same token.

Claims

1. Precast beam prestressed tendon tensioning device, comprising: A tensioning hydraulic system, which includes a hydraulic cylinder. The hydraulic cylinder includes a telescopic rod. The front end of the telescopic rod is connected to the prestressed tendon to be tensioned through a tensioning anchor. The tensioning anchor includes an anchor plate and wedge-shaped jaws. The anchor plate is provided with a tapered hole. The wedge-shaped jaws are formed by splicing multiple pieces and have a cylindrical inner part and a tapered outer part. One end of the prestressed tendon to be tensioned is wedged tightly in the tapered hole through the wedge-shaped jaws. The anchor plate is connected to the front end of the telescopic rod; It is characterized in that it further includes: A pressure control valve, which includes a valve core that can control the hydraulic pressure of the tensioning hydraulic system; the front end of the telescopic rod is connected to the anchor plate through a connecting sleeve. The length of the wedge-shaped jaws is greater than the depth of the tapered hole. The length of the wedge-shaped jaws extending out of the anchor plate increases with the increase in the diameter of the prestressed tendon to be tensioned. The length of the wedge-shaped jaws extending out of the anchor plate is in a proportional relationship with the displacement of the valve core. As the length of the wedge-shaped jaws extending out of the tapered hole increases, the internal flow cross-sectional area of the pressure control valve controlled by the valve core decreases, so that the diameter of the prestressed tendon to be tensioned is inversely proportional to the hydraulic pressure of the tensioning hydraulic system.

2. The prestressed tendon tensioning device for precast beams according to claim 1, wherein The wedge-shaped jaws and the valve core are connected by mechanical components, so that the valve core moves with the axial movement of the wedge-shaped jaws.

3. The precast beam prestressed tendon tensioning device according to claim 2, characterized in that, The outer end of the wedge-shaped jaws is connected with a sliding sleeve for sleeving on the prestressed tendon. The sliding sleeve is radially provided with a force transmission rod. The pressure control valve includes a valve body. The valve body is provided with a sliding hole. One end of the valve core is slidably and sealingly assembled at the sliding hole and extends outside the sliding hole. The other end of the force transmission rod abuts against the valve core to transmit displacement.

4. The precast beam prestressed tendon tensioning device according to claim 3, characterized in that, A spring is provided inside the valve body, and the spring provides an elastic acting force to the valve core in the direction of squeezing the force transmission rod.

5. The precast beam prestressed tendon tensioning device according to claim 4, characterized in that, The pressure control valve is a flow control valve. The valve body is provided with a first interface and a second interface that are interconnected. The valve body is connected in series to the main oil path of the tensioning hydraulic system through the first interface and the second interface. The valve core moves radially along the valve body to change the flow cross-sectional area of the internal channel of the valve body.

6. The precast beam prestressed tendon tensioning device according to claim 3, characterized in that, A relief long hole is provided on the connecting sleeve corresponding to the force transmission rod. The length of the relief long hole extends along the axial direction of the sliding sleeve. The force transmission rod can slide along the length direction of the relief long hole.

7. The precast beam prestressed tendon tensioning device according to claim 3, characterized in that An annular boss is provided on the inner peripheral surface of the connecting sleeve. The connecting sleeve is engaged with the anchor plate by hooking through the annular boss.

8. The precast beam prestressing tendon tensioning device according to claim 5, wherein, A tapered channel is provided on the internal channel of the valve body. A tapered platform is correspondingly provided at the inner end of the valve core. The adjustment of the flow cross-section is achieved through the cooperation of the tapered platform and the tapered channel.

9. A tensioning method using the tensioning device for prestressed tendons of precast beams according to any one of claims 1-8, characterized in that, Including the following steps: The two ends of the prestressed tendon are respectively sleeved into a pair of symmetrically arranged positioning anchors, and the end of the prestressed tendon to be tensioned is sleeved into the tensioning anchor; Make the length of the wedge-shaped jaws of the tensioning anchor extending out of the anchor plate be in a proportional relationship with the displacement of the valve core of the pressure control valve, so that as the length of the wedge-shaped jaws extending out of the tapered hole of the anchor plate increases, the internal flow cross-sectional area of the pressure control valve controlled by the valve core decreases, so that the diameter of the prestressed tendon is inversely proportional to the hydraulic pressure of the tensioning hydraulic system. The tensioning hydraulic system can change the corresponding hydraulic pressure according to the change in the diameter of the prestressed tendon and the relationship between the length of the wedge-shaped jaws extending out of the anchor plate and the displacement of the valve core.

10. The tensioning method of the tensioning device for the prestressed tendons of the precast beam according to claim 9, characterized in that, At least two sets of hydraulic cylinders of the same size are used in parallel. Correspondingly, at least two groups of tensioning platforms corresponding to the positioning anchors are used in parallel.

Images