CN216249673U

CN216249673U - Bolt type uninstallable prestressed reinforcement tensioning anchoring teaching demonstration device

Info

Publication number: CN216249673U
Application number: CN202122864578.XU
Authority: CN
Inventors: 王扶义; 王劭琨
Original assignee: Shaanxi Polytechnic Institute
Current assignee: Shaanxi Polytechnic Institute
Priority date: 2021-11-22
Filing date: 2021-11-22
Publication date: 2022-04-08
Anticipated expiration: 2031-11-22

Abstract

The utility model discloses a bolt type unloadable prestressed steel bar stretching anchoring teaching demonstration device, which relates to the technical field of teaching devices, wherein working anchors are respectively arranged at the outer sides of a first end of a first concrete beam body and a first end of a second concrete beam body, a prestressed steel bar is arranged between the two working anchors, a detachable unloading supporting frame is arranged outside the working anchor on the first concrete beam body, a through jack is arranged on the unloading supporting frame, and the prestressed steel bar respectively penetrates through the first concrete beam body, the working anchors and the unloading supporting frame to be detachably connected with the through jack; the second end of the first concrete beam body is movably connected with the second end of the second concrete beam body through a connecting device, and the connecting device adjusts the movement of the connecting device through an unloading device; the utility model can realize the teaching demonstration target of a laboratory and is suitable for a shorter stress unloading device of in-vivo prestressed steel bars.

Description

Bolt type uninstallable prestressed reinforcement tensioning anchoring teaching demonstration device

Technical Field

The utility model relates to the technical field of teaching devices, in particular to a bolt-type dismountable prestressed reinforcement tensioning anchoring teaching demonstration device.

Background

At present, the tension anchoring of prestressed reinforcements is a common and important construction process in bridge structures, and the necessary skills of students are to master the relevant processes and technical points of the construction. However, in practical teaching, since it is difficult to take off the anchor after the prestressed reinforcement is tensioned and anchored for reuse, the test equipment is scrapped, and the teaching investment is relatively large, so that in the general teaching process, the construction process is not demonstrated due to cost consideration, and the teaching effect is influenced to a certain extent.

The existing technology for prestressed reinforcement tensioning and anchoring mainly aims at prestressed reinforcement unloading in practical engineering, most unloading modes are modes of continuously tensioning prestressed reinforcement and withdrawing a clamping piece, and the mode is mainly suitable for the condition that the prestressed reinforcement is long. In the teaching, due to the limitation of fields and equipment, the prestressed steel bars are relatively short, if the stretching elongation is large, the stress is increased rapidly, the stress is close to or exceeds the bearing capacity, and great potential safety hazards exist; there are two main methods currently available for unloading prestressed reinforcements. The first type is to set up an uninstallation and hold the strength frame, and the strength frame is hollow tubbiness device, and during the use, one end supports on the beam-ends ground tackle, and jack and instrument anchor are installed to the other end, and the instrument anchor grasps the prestressing steel, and the jack is tensile with the prestressing steel, and during the drawing, the clamping piece on the work anchor is pulled out from the work anchor along with the prestressing steel, recycles the sharp-nosed plier and takes out the clamping piece, then the jack is retracted to realize the uninstallation of prestressing steel. This kind of uninstallation mode needs to continue stretch-draw the prestressed reinforcement that has anchored, and the clamping piece is taken out along with the extension of prestressed reinforcement, and this kind of mode is applicable to the longer condition of prestressed reinforcement, and if the prestressed reinforcement is shorter, the ratio of the elongation of the prestressed reinforcement that takes out the clamping piece required and prestressed reinforcement length is too big, and the increase of meeting an emergency is too big, then probably causes the prestressed reinforcement because of stress surpasss its bearing capacity and breaks.

The second is that when the prestressed reinforcement is stretched, a pulley block device is installed on the prestressed reinforcement, and when the prestressed reinforcement is required to be unloaded after stretching, the pulley block steel wire rope is loosened, similarly to a chain block device. Based on the analysis, the method has reference for the prestressed reinforcement tensioning and anchoring demonstration device used for teaching, but cannot be directly used, and firstly, because the length of the prestressed reinforcement of the demonstration device used for teaching is limited, the prestressed reinforcement is generally about 4 m; secondly, teaching usually demonstrates the tension anchoring of the prestressed reinforcement in the body, and the prestressed reinforcement is a permanent member; thirdly, the prior art is used for actual engineering, and no relevant technical data exist for the teaching demonstration device.

Disclosure of Invention

The utility model provides a bolt type uninstallable prestressed steel bar stretching and anchoring teaching demonstration device aiming at the problems, and solves the problem that the prestressed steel bar stretching and anchoring demonstration is inconvenient in the existing teaching process.

The technical scheme adopted by the utility model is as follows: a bolt-type unloadable prestressed reinforcement tensioning anchoring teaching demonstration device comprises a first concrete beam body, a second concrete beam body, a connecting device, an unloading device, a working anchor and prestressed reinforcements;

the outer sides of the first end of the first concrete beam body and the first end of the second concrete beam body are respectively provided with a working anchor, a prestressed steel bar is arranged between the two working anchors, and two ends of the prestressed steel bar respectively penetrate through the first concrete beam body and the second concrete beam body and are connected with the working anchors; a detachable unloading support frame is arranged outside the working anchor on the first concrete beam body, a feed-through jack is arranged on the unloading support frame, and the prestressed reinforcement bars respectively penetrate through the first concrete beam body, the working anchor and the unloading support frame and are detachably connected with the feed-through jack; the first concrete beam body second end and the second concrete beam body second end are movably connected through a connecting device, and the connecting device adjusts movement of the connecting device through an unloading device.

Further, the connecting device comprises a piston cylinder and a dowel bar; the concrete beam is characterized in that a plurality of piston cylinder first ends which are uniformly distributed are embedded in the side of the second end of the first concrete beam, a plurality of dowel bar first ends matched with the piston cylinders are embedded in the side of the second end of the second concrete beam, the second ends of the dowel bars slide in the second ends of the piston cylinders, and the dowel bars and the piston cylinders slide through the unloading device.

The unloading device comprises a force transmission plate, a first unloading bolt, a first transmission gear, a second unloading bolt, a gear shaft, a force transmission cylinder, a second transmission gear and a third transmission gear; a first end of a force transmission cylinder is embedded in a second end of the first concrete beam body, the prestressed reinforcement penetrates through the force transmission cylinder, the first concrete beam body and the second concrete beam body respectively and is connected with an external working anchor outside the force transmission cylinder, an external thread is arranged at the second end of the force transmission cylinder, a first unloading bolt matched with the second end of the force transmission cylinder is screwed at the second end of the force transmission cylinder, a first transmission gear is sleeved outside the first unloading bolt, a force transmission plate is movably sleeved at the second end of the force transmission cylinder, and the first unloading bolt is abutted against and in contact with the force transmission plate; the plurality of dowel bars penetrate through the dowel plates and are connected with the piston cylinder respectively; and a plurality of dowel bars are respectively and fixedly connected with the dowel plates, one side of the first transmission gear is meshed with a second transmission gear, the other side of the second transmission gear is meshed with a third transmission gear, the second transmission gear and the third transmission gear are both rotatably connected through a gear shaft and are arranged on the dowel plates, and a second unloading bolt is arranged on the third transmission gear.

Furthermore, a plurality of rivets are installed on the outer sides of the first end of the piston cylinder, the first end of the dowel bar and the first end of the dowel cylinder, and the rivets are arranged in the first concrete beam body and the second concrete beam body in a matched mode.

Further, the cross sections of the first concrete beam body and the second concrete beam body are of square structures.

Furthermore, the number of the piston cylinders is four, and the four piston cylinders are respectively arranged at four corners of the second end of the first concrete beam body.

Furthermore, the unloading support frame comprises four fixing columns, a first fixing plate and a second fixing plate; the two ends of each of the four fixing columns are respectively provided with a first fixing plate and a second fixing plate, a through hole is formed in the center of the second fixing plate, the working anchor is arranged in the through hole, the center of the first fixing plate is provided with a working hole, and the prestressed steel bars penetrate through the working holes and are connected with the center of the first fixing plate.

Furthermore, the connecting device, the unloading force-bearing frame, the force transmission plate and the force transmission barrel are all made of steel.

Further, the piston cylinder has a diameter dimension larger than a diameter dimension of the force transmission rod.

Furthermore, a round hole is formed in the center of the force transmission plate, the second end of the force transmission cylinder is arranged in the round hole, and the diameter of the round hole is smaller than the width of the first unloading bolt.

The utility model has the advantages that: the utility model provides a bolt type unloadable prestressed steel bar stretching anchoring teaching demonstration device, which is characterized in that a main beam body is divided into two ends of a first concrete beam body and a second concrete beam body and connected by a connecting device and an unloading device, the connecting device ensures the integrity and stability of the beam body during stretching, and the unloading device realizes the free expansion and contraction of the main beam body, so that the detachment of an anchorage device of a prestressed steel bar in a low stress state is realized; when the prestress is unloaded, the tensioning is not carried out continuously under the state that the stress of the prestressed reinforcement is larger, but the length of the prestressed reinforcement is firstly shortened, the tensioning is carried out after the stress of the prestressed reinforcement is released, the stress of the prestressed reinforcement is smaller, the clamping piece is relatively easy to take out, and the equipment scrap caused by the fact that the clamping piece cannot be taken out is avoided; meanwhile, the potential safety accident hazard caused by overlarge tension stress of the prestressed reinforcement in the unloading process is eliminated.

The prestressed anchorage device and the steel bar can be safely and conveniently taken out through the extension and retraction of the main beam body, so that the repeated use of the prestressed tension test demonstration equipment is ensured; the utility model can realize the teaching demonstration target of the laboratory, is beneficial to improving the teaching effect, reducing the teaching investment and improving the teaching effect; the device is suitable for a short stress unloading device of in-vivo prestressed steel bars, so that the prestressed steel bars and the anchorage devices in the test device can be disassembled.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model.

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of a second transfer gear installation of the present invention;

FIG. 3 is a schematic view of the unloading support frame of the present invention;

fig. 4 is a schematic structural diagram of the unloading device of the utility model.

Reference numerals: 1-a first concrete beam body, 2-a second concrete beam body, 3-a connecting device, 4-an unloading device, 5-a working anchor, 6-an unloading support frame, 7-prestressed reinforcements, 8-a penetrating jack and 9-a rivet; 31-piston cylinder, 32-dowel bar; 41-force transmission plate, 42-first unloading bolt, 43-first transmission gear, 44-second unloading bolt, 45-gear shaft, 46-corrugated pipe, 47-force transmission cylinder, 48-second transmission gear and 49-third transmission gear; 61-fixed column, 62-first fixed plate, 63-second fixed plate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Referring to fig. 1 to 4, a bolt-type unloadable prestressed reinforcement tension anchoring teaching demonstration device comprises a first concrete beam body 1, a second concrete beam body 2, a connecting device 3, an unloading device 4, a working anchor 5 and prestressed reinforcements 7; the cross sections of the first concrete beam body 1 and the second concrete beam body 2 are both square structures; the outer sides of the first end of the first concrete beam body 1 and the first end of the second concrete beam body 2 are respectively and fixedly provided with a working anchor 5, a prestressed steel bar 7 is arranged between the two working anchors 5, the working anchors 5 are commercially available and internally provided with clamping pieces for fastening the prestressed steel bar 7, and two ends of the prestressed steel bar 7 respectively penetrate through the first concrete beam body 1 and the second concrete beam body 2 and are connected with the working anchors 5; preferably, corrugated pipes 46 are pre-embedded in the central positions of the first concrete beam body 1 and the second concrete beam body 2, the corrugated pipes 46 are commercially available and are necessary components of the prestressed concrete beam body in the body, and holes for installing prestressed reinforcements 7 are formed when the beam body is manufactured; a detachable unloading support frame 6 is arranged outside the working anchor 5 on the first concrete beam body 1, a through jack 8 is arranged on the unloading support frame 6, the through jack 8 is commercially available, and the prestressed reinforcement 7 respectively penetrates through the first concrete beam body 1, the working anchor 5 and the unloading support frame 6 and is detachably connected with the through jack 8; preferably, the unloading holding frame 6 comprises four fixing posts 61, a first fixing plate 62 and a second fixing plate 63; the two ends of each of the four fixing columns 61 are respectively fixedly provided with a first fixing plate 62 and a second fixing plate 63, the center of the second fixing plate 63 is provided with a through hole, the working anchor 5 is arranged in the through hole, the center-through jack 8 is arranged on the first fixing plate 62, the center of the first fixing plate 62 is provided with a working hole, the prestressed reinforcement 7 penetrates through the working hole and is connected with the center-through jack 8, the four fixing columns 61 are formed by four steel columns, and the first fixing plate 62 and the second fixing plate 63 are two steel plates which are welded in the process; the aperture size of the through hole is slightly larger than that of the working anchor, and the aperture size of the working hole is smaller and can pass through the prestressed reinforcement 7; the second end of the first concrete beam body 1 is movably connected with the second end of the second concrete beam body 2 through a connecting device 3, and preferably, the connecting device 3 comprises a piston cylinder 31 and a dowel bar 32; a plurality of uniformly distributed first ends of piston cylinders 31 are embedded in the peripheral side of the second end of the first concrete beam body 1, the piston cylinders 31 are steel pipes, furthermore, the number of the piston cylinders 31 is four, and four piston cylinders 31 are respectively arranged at four corners of the second end of the first concrete beam body 1, a plurality of first ends of dowel bars 32 matched with the piston cylinders 31 are embedded in the peripheral side of the second end of the second concrete beam body 2, namely, the piston cylinder 31 is pre-embedded at four corners of the second end of the second concrete beam body 2, the dowel bar 32 is formed by processing round thick steel bars, the second end of the dowel bar 32 slides in the second end of the piston cylinder 31, the dowel bar 32 and the piston cylinder 31 are regulated to slide by the unloading device 4, and preferably, the unloading device 4 comprises a dowel plate 41, a first unloading bolt 42, a first transmission gear 43, a second unloading bolt 44, a gear shaft 45, a transmission cylinder 47, a second transmission gear 48 and a third transmission gear 49; a first end of a force transmission cylinder 47 is embedded in a second end of the first concrete beam body 1, the force transmission cylinder 47 and a corrugated pipe 46 are coaxially arranged, the prestressed reinforcement 7 respectively penetrates through the force transmission cylinder 47, the first concrete beam body 1 and the second concrete beam body 2 and is connected with an external working anchor 5 outside the force transmission cylinder, the force transmission cylinder 47 is a steel pipe with a thicker wall thickness, the diameter of the steel pipe is convenient for the prestressed reinforcement 7 to penetrate through and to be convenient for test operation, a second end of the force transmission cylinder 47 is provided with an external thread, a second end of the force transmission cylinder 47 is in threaded connection with a first unloading bolt 42 which is matched with the second end of the force transmission cylinder 47, a first transmission gear 43 is fixedly sleeved outside the first unloading bolt 42, a force transmission plate 41 is movably sleeved at the second end of the force transmission cylinder 47, namely, a non-threaded section end of the force transmission cylinder 9 is embedded in the first concrete beam body 1, the first unloading bolt 42 is installed on a threaded section of the force transmission cylinder 9, the threaded section of the force transmission cylinder 9 penetrates through the force transmission plate 41 and can slide on the force transmission plate 41, the first unloading bolt 42 is in abutting contact with the force transmission plate 41, the force transmission plate 41 is a steel plate, a gap is reserved between the first transmission gear 43 and the force transmission plate 41, the transmission of the first transmission gear 43 is prevented from being interfered, and the first unloading bolt 42 is in abutting contact with the force transmission plate 41; the plurality of dowel bars 32 respectively penetrate through the dowel plates 41 and are connected with the piston cylinder 31; and a plurality of dowel bars 32 are respectively and fixedly connected with the dowel plate 41, one side of the first transmission gear 43 is meshed with a second transmission gear 48, the other side of the second transmission gear 48 is meshed with a third transmission gear 49, the second transmission gear 48 and the third transmission gear 49 are both rotatably connected through a gear shaft 45 and are arranged on the dowel plate 41, and a second unloading bolt 44 is fixedly arranged on the third transmission gear 49.

The utility model provides a bolt type unloaded prestressed reinforcement tensioning anchoring teaching demonstration device, when a tensioning test is carried out, a second unloading bolt 44 needs to be screwed, the second unloading bolt 44 drives a third transmission gear 49 to rotate, the third transmission gear 49 is meshed with a second transmission gear 48 to drive the second transmission gear 48 to rotate, the second transmission gear 48 is meshed with a first transmission gear 43 to drive the first transmission gear 43 to rotate, the first unloading bolt 42 is screwed through the first transmission gear 43 to enable a force transmission cylinder 47 to move, so that the second end of a first concrete beam body 1 and a second concrete beam body 2 are driven to be far away, and then a tensioning anchoring process demonstration of a prestressed reinforcement 7 is carried out; during unloading, an unloading supporting frame 6 is arranged at the first end of the first concrete beam body 1, and a feed-through jack 8 is arranged on a second fixing plate 63; reversely screwing the second unloading bolt 44, driving the third transmission gear 49 to rotate by the second unloading bolt 44, meshing the third transmission gear 49 with the second transmission gear 48 to drive the second transmission gear 48 to rotate, meshing the second transmission gear 48 with the first transmission gear 43 to drive the first transmission gear 43 to rotate, screwing the first unloading bolt 42 by the first transmission gear 43 to move the force transmission cylinder 47, and realizing the approach of the second end of the first concrete beam body 1 and the second concrete beam body 2, wherein when the second end of the first concrete beam body 1 and the second concrete beam body 2 approach, the stress of the tensioned prestressed reinforcement 7 is reduced, and the prestressed reinforcement is screwed until the prestressed reinforcement is completely unstressed, loosened and even pressed and bent; then, a feed-through jack 8 is arranged on the unloading support frame 6 to stretch the prestressed reinforcement 7, so that the clamping piece of the working anchor 5 withdraws along with the stretching of the prestressed reinforcement 7, and the clamping piece of the working anchor 5 can be conveniently taken out of the gap of the support frame; at the moment, the elongation of the prestressed reinforcement 7 is small, so that the stress increment is limited, and the prestressed reinforcement 7 cannot be broken; can take out work anchor 5 and clamping piece on it, prestressing steel 7 completely through uninstallation device 4, realize the used repeatedly of test device, and the uninstallation is comparatively safe.

In an embodiment of the utility model, a plurality of rivets 9 are respectively arranged at the outer sides of the first end of the piston cylinder 31, the first end of the dowel bar 32 and the first end of the dowel cylinder 47, and the plurality of rivets 9 are respectively arranged in the first concrete beam body 1 and the second concrete beam body 2 in a matched manner, so that the piston cylinder 31, the dowel bar 32 and the dowel cylinder 47 are respectively embedded in the first concrete beam body 1 and the second concrete beam body 2 more stably and are connected more firmly.

In one embodiment of the present invention, the diameter of the piston cylinder 31 is larger than the diameter of the force transmission rod 32, so that the force transmission rod 32 can enter the piston cylinder 31 and slide in the piston cylinder 31.

In an embodiment of the present invention, a circular hole is formed in the center of the force transmission plate 41, the second end of the force transmission cylinder 47 is disposed in the circular hole, so that the force transmission cylinder 47 can conveniently penetrate through the force transmission plate 41, and the diameter of the circular hole is smaller than the width of the first unloading bolt 42, so as to prevent the first unloading bolt 42 from penetrating through, and the force transmission plate 41 can conveniently make the first unloading bolt 42 and the force transmission plate 41 tightly contact with each other.

The utility model provides a bolt type unloadable prestressed steel bar stretching and anchoring teaching demonstration device, which is characterized in that a main beam body is divided into two ends of a first concrete beam body and a second concrete beam body and connected by a connecting device and an unloading device, the integrity and stability of the beam body during stretching are ensured by the connecting device, the unloading device realizes free expansion and contraction of the main beam body, and therefore the detachment of an anchorage device of a prestressed steel bar in a low stress state is realized.

When the prestress is unloaded, the tensioning is not carried out continuously under the state that the stress of the prestressed reinforcement is larger, but the length of the prestressed reinforcement is firstly shortened, the tensioning is carried out after the stress of the prestressed reinforcement is released, the stress of the prestressed reinforcement is smaller, the clamping piece is relatively easy to take out, and the equipment scrap caused by the fact that the clamping piece cannot be taken out is avoided; meanwhile, the potential safety accident hazard caused by overlarge tension stress of the prestressed reinforcement in the unloading process is eliminated.

The prestressed anchorage device and the steel bar can be safely and conveniently taken out through the extension and retraction of the main beam body, and the repeated use of the prestressed tension test demonstration equipment is ensured.

The utility model can realize the teaching demonstration target of the laboratory, is beneficial to improving the teaching effect, reducing the teaching investment and improving the teaching effect; the device is suitable for a short stress unloading device of in-vivo prestressed steel bars, so that the prestressed steel bars and the anchorage devices in the test device can be disassembled.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A bolt type unloadable prestressed steel tensioning anchoring teaching demonstration device is characterized by comprising a first concrete beam body (1), a second concrete beam body (2), a connecting device (3), an unloading device (4), a working anchor (5) and prestressed steel bars (7); the outer sides of the first end of the first concrete beam body (1) and the first end of the second concrete beam body (2) are respectively provided with a working anchor (5), a prestressed reinforcement (7) is arranged between the two working anchors (5), and two ends of the prestressed reinforcement (7) respectively penetrate through the first concrete beam body (1) and the second concrete beam body (2) and are connected with the working anchors (5); a detachable unloading supporting frame (6) is arranged outside a working anchor (5) on the first concrete beam body (1), a feed-through jack (8) is arranged on the unloading supporting frame (6), and the prestressed reinforcement (7) respectively penetrates through the first concrete beam body (1), the working anchor (5) and the unloading supporting frame (6) and is detachably connected with the feed-through jack (8); the second end of the first concrete beam body (1) is movably connected with the second end of the second concrete beam body (2) through a connecting device (3), and the connecting device (3) adjusts the movement of the connecting device through an unloading device (4).

2. Bolted unloadable prestressed reinforcement tension-anchoring educational demonstration device according to claim 1, characterized in that said connection means (3) comprise a piston cylinder (31) and a dowel bar (32); the concrete beam is characterized in that a plurality of evenly distributed piston cylinders (31) first ends are embedded in the second end periphery of the first concrete beam body (1), a plurality of dowel steel (32) first ends matched with the piston cylinders (31) are embedded in the second end periphery of the second concrete beam body (2), the second ends of the dowel steel (32) slide in the second ends of the piston cylinders (31), and the dowel steel (32) and the piston cylinders (31) slide through the unloading device (4).

3. The bolt-style unloadable prestressed reinforcement tension-anchoring teaching demonstration device according to claim 2, wherein the unloading device (4) comprises a force transmission plate (41), a first unloading bolt (42), a first transmission gear (43), a second unloading bolt (44), a gear shaft (45), a force transmission cylinder (47), a second transmission gear (48) and a third transmission gear (49); a first end of a force transmission cylinder (47) is embedded in a second end of the first concrete beam body (1), the prestressed reinforcement (7) penetrates through the force transmission cylinder (47), the first concrete beam body (1) and the second concrete beam body (2) respectively and is connected with an external working anchor (5) outside the force transmission cylinder, an external thread is arranged at the second end of the force transmission cylinder (47), a first unloading bolt (42) matched with the second end of the force transmission cylinder (47) is in threaded connection, a first transmission gear (43) is sleeved outside the first unloading bolt (42), a force transmission plate (41) is movably sleeved at the second end of the force transmission cylinder (47), and the first unloading bolt (42) is in abutting tight contact with the force transmission plate (41); the force transfer rods (32) penetrate through the force transfer plate (41) and are connected with the piston cylinder (31) respectively; and a plurality of dowel bars (32) are respectively and fixedly connected with a dowel plate (41), a second transmission gear (48) is meshed on one side of the first transmission gear (43), a third transmission gear (49) is meshed on the other side of the second transmission gear (48), the second transmission gear (48) and the third transmission gear (49) are both rotatably connected through a gear shaft (45) and are arranged on the dowel plate (41), and a second unloading bolt (44) is arranged on the third transmission gear (49).

4. The bolt-type unloadable prestressed reinforcement tensioning and anchoring teaching demonstration device according to claim 3, wherein a plurality of rivets (9) are mounted on the outer sides of the first end of the piston cylinder (31), the first end of the dowel bar (32) and the first end of the dowel cylinder (47), and the rivets (9) are respectively arranged in the first concrete beam body (1) and the second concrete beam body (2) in a matched manner.

5. The bolt-style unloadable prestressed reinforcement tension-anchoring teaching demonstration device according to claim 4, characterized in that the cross sections of the first concrete beam body (1) and the second concrete beam body (2) are both square structures.

6. The bolt-type unloadable prestressed reinforcement tensioning and anchoring teaching demonstration device according to claim 5, wherein the number of the piston cylinders (31) is four, and the four piston cylinders (31) are respectively installed at four corners of the second end of the first concrete beam body (1).

7. The bolt-style unloadable prestressed reinforcement tension anchor teaching demonstration device according to claim 6, wherein said unloading support frame (6) comprises four fixing posts (61), a first fixing plate (62) and a second fixing plate (63); first fixed plate (62) and second fixed plate (63) are respectively installed at two ends of four fixed columns (61), a through hole is formed in the center of the second fixed plate (63), the working anchor (5) is arranged in the through hole, the center-through jack (8) is installed on the first fixed plate (62), a working hole is formed in the center of the first fixed plate (62), and the prestressed reinforcement (7) penetrates through the working hole and is connected with the center-through jack (8).

8. Bolt-style unloadable prestressed reinforcement tension-anchoring teaching demonstration device according to claim 7, characterized in that the connection means (3), the unloading support frame (6), the force transfer plate (41) and the force transfer cylinder (47) are all steel.

9. The bolt-style unloadable prestressed reinforcement tension anchor teaching demonstration device according to claim 2, wherein the diameter dimension of said piston cylinder (31) is greater than the diameter dimension of the dowel (32).

10. The bolt-type unloadable prestressed steel bar tension-anchoring teaching demonstration device according to claim 3, wherein a circular hole is formed in the center of the force transmission plate (41), the second end of the force transmission cylinder (47) is arranged in the circular hole, and the diameter of the circular hole is smaller than the width of the first unloading bolt (42).