A construction method for large-volume high-support prestressed concrete beams

Abstract

The present invention discloses a method for constructing a large-volume, high-support prestressed concrete beam, which belongs to the technical field of prestressed beam construction. The construction preparation work includes presetting a full-length steel wire rope in a reserved channel for prestressed steel strands, installing a steel strand anchoring mechanism on the entrance side of the reserved channel, installing a limit plate on the exit side of the reserved channel, and presetting marks at the corresponding lengths of the steel strands extending from the movable pipe according to the length of the reserved channel; using the steel strand anchoring mechanism, multiple steel strands are synchronously pulled to the limit plate for cooperation, and the marks on the steel strands are adjusted to the same plane; the steel strands outside the reserved pipe near the anchor plate are cut, and a movable plate is installed, and the movable plates on both sides of the steel strands are tensioned to a preset elongation value; after tensioning is completed, grouting is performed in the reserved channel, and concrete is poured to form the beam body. The present invention can pipe multiple steel strands in the reserved channel as a whole, avoiding friction on the inner wall of the reserved channel and on the steel strands caused by pipe-lining individual steel strands.

Description

Technical Field

[0001] The invention belongs to the technical field of prestressed beam construction, and in particular relates to a construction method of a large-volume high-support prestressed concrete beam. Background Art

[0002] With economic development, the demand for diverse building functions is increasing. Building height and span are crucial factors in achieving this diversity. Large-volume prestressed beams utilize high-strength steel strands and high-strength concrete to reduce beam cross-sections, reduce deadweight, and increase load-bearing capacity. These beams are widely used in the construction of buildings with large-span overhead spaces.

[0003] The construction of large-volume prestressed concrete beams involves the tensioning of prestressed steel strands. Traditionally, the steel strands are manually fed into the corrugated tube one by one. This results in the subsequent steel strands being easily rubbed against the already fed steel strands and the corrugated tube during the process of feeding multiple steel strands in sequence, and wastes manpower.

[0004] Therefore, it is necessary to propose a construction method for large-volume high-support prestressed concrete beams to solve the above problems. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for constructing large-volume high-support prestressed concrete beams, which is used to solve the problem in the prior art of manually feeding steel strands into corrugated pipes one by one, resulting in the subsequent steel strands easily causing friction between the already fed steel strands and the corrugated pipe during the process of feeding multiple steel strands in sequence, and wasting manpower.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for constructing a large-volume high-support prestressed concrete beam, comprising the following steps:

[0008] S1: Construction preparation work: erecting high supports, installing formwork, and tying steel bars;

[0009] S2: Preset a full-length steel wire rope in the reserved channel for prestressed steel strands, install a steel strand anchoring mechanism on the entrance side of the reserved channel, and install a limit plate on the exit side of the reserved channel.

[0010] Wherein, the steel strand anchoring mechanism comprises: an anchoring plate fixedly mounted on the entrance side of the reserved channel, a plurality of first through holes for passing the steel strands are circumferentially provided on the anchoring plate with the axis of the anchoring plate as the center, a movable plate is detachably fixedly mounted on the anchoring plate near the exit side of the reserved channel, the movable plate comprises a connecting portion detachably connected to the anchoring plate and a traction portion detachably connected to the connecting portion, a second through hole corresponding to the first through hole is provided on the connecting portion, a plurality of clamping pieces for clamping the steel strands that can slide along the radial direction of the second through hole are installed in the second through hole with the axis of the second through hole as the center;

[0011] Passing multiple steel strands through the first through hole and the second through hole respectively, clamping and fixing the steel strands with the clamping pieces, and then connecting the steel wire ropes preset in the reserved channels to the traction part;

[0012] S3: Preset a mark at the corresponding length of the steel strand extending from the movable door according to the length of the reserved channel;

[0013] S4: Pull the steel wire rope through the traction mechanism until the movable plate and the limit plate are matched, and adjust the marks on the steel strand to the same plane;

[0014] S5: Cut the steel strands outside the reserved pipe near the anchor plate, install movable plates, and tension the movable plates on both sides of the steel strands to a preset elongation value;

[0015] S6: After tensioning is completed, grouting is carried out in the reserved channels and concrete is poured to form the beam body.

[0016] Furthermore, a cavity corresponding to the second through hole is provided in the connecting portion, and a limiting column extending into the cavity is fixedly connected to the clamping piece, and the clamping piece can slide in a limited radial direction of the second through hole through the limiting column. A gear is rotatably installed in the cavity, and a screw is coaxially fixedly connected to the gear. The screw is threadedly connected to the limiting column, and rotating the screw can cause the limiting column to slide. A toothed disc is rotatably installed in the cavity, and the toothed disc is engaged with a plurality of gears.

[0017] When installing the steel strand, the steel strand is passed through the second through hole, and the toothed disc is rotated to allow the multiple gears to slide synchronously, so that the holding piece clamps the steel strand.

[0018] Furthermore, a first gear ring is sleeved on the outer circumferential wall of the gear disc, and a plurality of second gear rings are rotatably mounted in the connecting portion and mesh with the first gear rings arranged along the same circumference;

[0019] When installing the steel strands, after all the steel strands are passed through the second through holes, the second gear ring is rotated so that the clamping pieces in the second through holes clamp the steel strands.

[0020] Furthermore, the connecting part is provided with an arc-shaped limiting hole which is consistent with the curvature of the second gear ring, and the second gear ring is installed with an arc-shaped limiting plate which can extend out of the arc-shaped limiting hole, and the arc-shaped limiting plate slides in the arc-shaped limiting hole, and the traction part is provided with a slot which cooperates with the arc-shaped limiting plate, and the connecting part is provided with a threaded hole, and the traction part is threadedly connected to the threaded hole. After the traction part slides into the threaded hole along the arc-shaped limiting plate through the slot, rotating the traction part can rotate the second gear ring so that the clamping piece clamps the steel strand and the traction part can be threadedly fixed to the connecting part.

[0021] Furthermore, the arc-shaped limit plate is connected to the second gear ring in a limiting sliding manner, and an empty groove is provided in the arc-shaped limit plate. A limit block that can extend into the empty groove is installed on the second gear ring, and a spring is connected between the limit block and the inner wall of the empty groove.

[0022] Furthermore, a threaded sleeve is threadedly connected to the anchor plate, and the threaded sleeve is provided with the first through hole;

[0023] After passing through the first through hole, the steel strand can slide freely along the first through hole. When the movable plate drives the steel strand to move until the movable plate and the limit plate are fixed, the threaded sleeve is fixed to the steel strand so that the steel strand cannot slide along the first through hole. At this time, rotating the threaded sleeve can adjust the position of the steel strand so that the marks on the steel strand are in the same plane.

[0024] Furthermore, the limiting plate and the anchoring plate are both provided with limiting holes, and the movable plate is provided with a socket coaxially arranged with the limiting hole;

[0025] Before installing the steel strand, the movable plate and the anchor plate are fixed by means of a pin. At this time, the first through hole and the second through hole are connected to form a movable channel for the steel strand. After the steel strand is passed through the first through hole and out of the second through hole, the pin between the movable plate and the anchor plate is taken out, and the steel wire rope is pulled by the traction mechanism until the movable plate cooperates with the limit plate, and then the limit plate and the movable plate are fixed by the pin.

[0026] The beneficial effects of the present invention are:

[0027] The present invention adopts prestressing technology to pre-apply prestress, so that the concrete beam has higher strength and bearing capacity. The tensioning of the prestressed steel bundles can effectively offset the self-cracking and deformation of the concrete during use, thereby improving the overall performance of the beam; the high-support construction method is adopted to greatly improve the construction efficiency, while shortening the construction period and reducing the waste of manpower, material and financial resources; by setting a movable plate, multiple steel strands in the reserved channel can be piped through as a whole bundle at one time, avoiding friction on the inner wall of the reserved channel and the remaining steel strands caused by the separate pipe insertion of a single steel strand; at the same time, by using the limit plate and pre-marking the steel strands, it is convenient to adjust the consistency of the steel strands in the reserved channel before tensioning, thereby ensuring the consistency of the elongation of multiple steel strands during synchronous tensioning.

[0028] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration:

[0030] Figure 1 This is a schematic diagram of the assembly of the anchor plate and the movable plate according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the assembly of the anchor plate and the movable plate according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the installation of an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the installation of the anchor plate and the movable plate according to an embodiment of the present invention;

[0034] Figure 5 is a cross-sectional view of a connection portion according to an embodiment of the present invention;

[0035] Figure 6 For the embodiment of the present invention Figure 5 Enlarged view of the part A in the middle;

[0036] Figure 7 This is a schematic structural diagram of a connecting portion according to an embodiment of the present invention;

[0037] Figure 8 Schematic diagram of the cooperation between the limiting block and the empty slot according to an embodiment of the present invention.

[0038] The markings in the accompanying drawings are as follows: reserved channel 1, wire rope 2, limiting plate 3, anchor plate 4, first through hole 401, threaded sleeve 402, movable plate 5, connecting part 501, traction part 502, clamping plate 503, threaded hole 504, limiting column 505, gear 506, screw 5071, toothed disc 5071, first gear ring 508, second gear ring 509, arc-shaped limiting hole 510, arc-shaped limiting plate 511, slot 512, empty slot 514, limiting block 515, spring 516, second through hole 517, steel strand 6, limiting hole 7, jack 701, and pin 702. DETAILED DESCRIPTION

[0039] like Figures 1 to 8 As shown, the present invention provides a method for constructing a large-volume high-support prestressed concrete beam, comprising the following steps:

[0040] S1: Construction preparation work: After the high support is erected, the formwork is installed and the steel bars are tied. The construction preparation work is a conventional method that is familiar to those skilled in the art and will not be described in detail here.

[0041] S2: A full-length steel wire rope 2 is preset in the reserved channel 1 for prestressed steel strands, wherein the reserved channel 1 adopts a galvanized double-corrugated metal bellows; a steel strand anchoring mechanism is installed on the inlet side of the reserved channel 1, and a limit plate 3 is installed on the outlet side of the reserved channel 1, wherein the steel strand anchoring mechanism includes: an anchoring plate 4 fixedly installed on the inlet side of the reserved channel 1, and a plurality of first through holes 401 for the steel strand 6 to pass through are provided on the anchoring plate 4 with the axis of the anchoring plate 4 as the center. The anchoring plate 4 is close to the outlet side of the reserved channel 1. A movable plate 5 is detachably fixedly installed, the diameter of the movable plate 5 being smaller than the diameter of the reserved channel 1, the movable plate 5 comprising a connecting portion 501 detachably connected to the anchor plate 4 and a traction portion 502 detachably connected to the connecting portion 501, the connecting portion 501 being provided with a second through hole 517 corresponding one-to-one with the first through hole 401, a plurality of clamping pieces 503 for clamping the steel strand 6 being slidable in the radial direction of the second through hole 517 being installed in the second through hole 517 with the axis of the second through hole 517 as the center;

[0042] Pass multiple steel strands 6 through the first through hole 401 and the second through hole 517 respectively. After the steel strands 6 are clamped and fixed by the clamping piece 503, the steel wire rope 2 preset in the reserved channel 1 is connected to the traction part 502.

[0043] S3: Preset a mark at the corresponding length of the steel strand 6 extending from the movable plate 5 according to the length of the reserved channel 1;

[0044] S4: Pull the steel wire rope 2 through the traction mechanism, wherein the traction mechanism is a winch, and drive the movable plate 5 to move closer to the reserved channel outlet side so that the movable plate 5 and the limit plate 3 are limited. At this time, observe the distance between the mark on the steel strand 6 and the side wall of the anchor plate 4. If the distance is consistent, no adjustment is required. If the distance is inconsistent, pull the steel strand 6 so that the marks on all the steel strands 6 are on the same plane;

[0045] S5: After the steel strand 6 is adjusted, the marked side of the steel strand 6 is cut by a grinding wheel saw, and a movable plate 5 is installed. The movable plates 5 on both sides of the steel strand 6 are tensioned. During tensioning, it is necessary to monitor in real time whether the relative deviation between the actual elongation value of the steel strand and the calculated elongation value exceeds the preset value. If it exceeds, the tensioning needs to be suspended and adjusted to within the preset value before continuing the tensioning;

[0046] S6: After tensioning is completed, grouting is performed in the reserved channel 1;

[0047] Among them, the cement slurry used for grouting in the reserved channel 1 should be made of ordinary Portland cement and water; the grouting should be carried out slowly and continuously without interruption, and the exhaust should be smooth. After the channel is filled and the exhaust hole is closed, the pressure should be continued, and the grouting hole should be closed after the pressure is stabilized; when the channel is blocked or the grouting is interrupted, the channel should be flushed in time or other measures should be taken to re-grout. After tensioning, the area around the anchor end should be rinsed and roughened first, and a short steel bar with a hook at one end should be welded to the steel plate and tied together with the anchor steel mesh. Then, the anchor concrete should be poured in the formwork. The end concrete should be made of slightly expanded fine stone concrete, and it should be maintained in time after pouring.

[0048] S7: pouring concrete to form the beam;

[0049] Among them, the pouring of beam concrete adopts a construction method of continuous pouring in sections and horizontal layers, and a step-by-step construction method from one end to the other. The material is first poured from the middle of the webs on both sides of the beam to both ends until it turns around and pours at the beam ends. It is carried out synchronously, symmetrically and evenly, first pouring the bottom plate, then pouring the webs, and finally pouring the top plate; when pouring the concrete of the two webs of the beam, the web concrete is poured synchronously and symmetrically; when the two web grooves are poured flat, the beam panel concrete is poured; the beam surface concrete also starts from one end, is poured in sections, and is poured continuously to the other end; during the pouring process, a special person is assigned to check the formwork and steel bars, and tighten and secure the bolts, supports, etc. if they are loose; if leakage is found, it is blocked in time, and if the steel bars and embedded parts are displaced, they are adjusted in time to ensure the correct position; when pouring concrete into the formwork, the material should be evenly discharged, and attention should be paid to vibration In coordination, the vibration and feeding of concrete are carried out alternately; the beam concrete is poured and formed by vibrating with an inserted high-frequency vibrating rod. The vibration time of the concrete is when the concrete surface no longer sinks, no bubbles escape, and the concrete surface begins to become slurry; when operating the inserted vibrating rod, it is advisable to insert it quickly and withdraw it slowly, and vibrate vertically. It is not allowed to pull it horizontally, and no vibration should be missed. Be careful to prevent over-vibration; the vibrating rod twitches slightly up and down during vibration; during the pouring process, pay attention to strengthening the vibration of chamfers, interfaces and areas with dense steel bars; before pouring, check the position, quantity and tightness of the steel bar protective layer pads; check whether all model fasteners are tightened and intact; whether there are gaps in the model interface; whether the vibrator is intact; concrete should be cured immediately after pouring. During the curing period, the concrete surface should be kept moist to prevent rain and sun. For the exposed surface of concrete, cover it with geotextile + curing film immediately after the surface has set and solidified, and sprinkle water on the geotextile and formwork to keep the concrete surface moist. The concrete should be protected from vibration during the curing period or before it reaches a certain strength. To prevent concrete cracking, use cement with small shrinkage, reduce cement dosage and water-cement ratio, and optimize aggregate grading. Strengthen on-site management, strictly control cement dosage, water-cement ratio, sand content, slump and other indicators, ensure that the concrete is vibrated and compacted, and maintained with water.

[0050] In this solution, by adopting prestressing technology and prestressing in advance, the concrete beam has higher strength and bearing capacity, and the tensioning of the prestressed steel bundles can effectively offset the self-cracking and deformation of the concrete during use, thereby improving the overall performance of the beam; the high-support construction method is adopted to greatly improve the construction efficiency, while shortening the construction period and reducing the waste of manpower, material and financial resources; by setting up a movable plate 5, the multiple steel strands 6 in the reserved channel 1 can be piped through as a whole bundle at one time, avoiding the friction of the inner wall of the reserved channel 1 and the remaining steel strands 6 caused by the separate pipe insertion of a single steel strand 6, and at the same time, by using the limit plate 3 and pre-marking the steel strands 6, it is convenient to adjust the consistency of the steel strands 6 in the reserved channel 1 before tensioning, thereby ensuring the consistency of the elongation of multiple steel strands 6 during synchronous tensioning.

[0051] In one embodiment of the present invention, a cavity corresponding to the second through hole 517 is provided in the connecting portion 501, and a limiting column 505 extending into the cavity is fixedly connected to the clamping piece 503. The clamping piece 503 can slide radially along the second through hole 517 through the limiting column 505. A gear 506 is rotatably installed in the cavity. The gear 506 is coaxially fixedly connected to a screw 5071. The screw 5071 is threadedly connected to the limiting column 505. Rotating the gear 506 can limit the sliding of the limiting column 505 along the radial direction of the second through hole 517. A toothed disc 5071 is rotatably installed, and the toothed disc 5071 is engaged with multiple gears 506. Rotating the toothed disc 5071 can make the multiple gears 506 slide synchronously so that the clamping piece 503 can clamp or loosen the steel strand passing through the second through hole 517; the outer circumferential wall of the toothed disc 5071 is provided with a first toothed ring 508, and the connecting part 501 is rotatably installed with a second toothed ring 509 that is engaged with multiple first toothed rings 508 arranged along the same circumference. Rotating the second toothed ring 509 can make the clamping pieces 503 in multiple second through holes 517 arranged along the same circumference clamp or loosen the steel strand 6.

[0052] In this solution, the above-mentioned structural design facilitates synchronous clamping of the steel strand 6 passing through the second through hole 517 for tensioning or loosening for taking and placing.

[0053] In one embodiment of the present invention, the connecting portion 501 is provided with an arc-shaped limiting hole 510 having the same curvature as the second gear ring 509, and the second gear ring 509 is provided with an arc-shaped limiting plate 511 that can extend the arc-shaped limiting hole 510, and the arc-shaped limiting plate 511 slides in the arc-shaped limiting hole 510, and the traction portion 502 is provided with a slot 512 that cooperates with the arc-shaped limiting plate 511, and the connecting portion 501 is provided with a threaded hole 504, and the traction portion 502 is threadedly connected to the threaded hole 504. After the traction portion 502 slides into the threaded hole 504 along the arc-shaped limiting plate 511 through the slot 512, rotating the traction portion 502 can rotate the second gear ring 509 so that the clamping piece 503 clamps the steel strand 6 and can thread the traction portion 502 to the connecting portion 502.

[0054] In one embodiment of the present invention, the arc-shaped limit plate 511 is slidingly connected to the second gear ring 509, and a slot 514 is provided in the arc-shaped limit plate 511. A limit block 515 that can extend into the slot 514 is installed on the second gear ring 509, and a spring 516 is connected between the limit block 515 and the inner wall of the slot 514.

[0055] In this solution, after the slot 512 of the traction part 502 is inserted along the arc-shaped limit plate 511, the traction part 502 is rotated so that the traction part 502 is screwed into the threaded hole 504. At this time, the traction part 502 drives the arc-shaped limit plate 511 to slide along the second gear ring 509 during rotation to compress the spring 516, and drives the second gear ring 509 to rotate through the spring 516 and the limit block 515, wherein the second gear ring 509 is limitedly rotated and installed in the connecting part 501. When the second gear ring 509 is rotated to the limit position (that is, the second gear ring 509 is rotated so that the clamping plate 503 clamps the steel strand 6, which is the limit position of the rotation of the second gear ring 509), the traction part 502 continues to be rotated to further compress the spring 516, thereby improving the stability of the clamping.

[0056] This solution ensures that when the rotation angle of the second gear ring 509 is limited, the traction part 502 can be screwed into the threaded hole 504 to a sufficient length by setting a limit block 515 and a spring 516 in cooperation with the arc-shaped limit plate 511, so as to ensure the stability of the threaded connection between the traction part 502 and the connecting part 501, and avoid the situation where the traction part 502 is screwed into the connecting part 501 to a too short length after the second gear ring 509 is rotated to the extreme position, resulting in the traction part 502 being separated from the connecting part 501 during traction or tensioning.

[0057] In one embodiment of the present invention, a threaded sleeve 402 is threadedly connected to the anchoring plate 4 , and the first through hole 401 is defined in the threaded sleeve 402 .

[0058] In this solution, the steel strand 6 can slide freely along the first through hole 401 after passing through the first through hole 401. When the movable plate 5 drives the steel strand 6 to move until the movable plate 5 and the limiting plate 3 are fixed, the threaded sleeve 402 is fixed to the steel strand 6 so that the steel strand 6 cannot slide along the first through hole 401. At this time, rotating the threaded sleeve 402 can adjust the position of the steel strand 6 so that the marks on the steel strand 6 are in the same plane.

[0059] In one embodiment of the present invention, the limiting plate 3 and the anchoring plate 4 are both provided with limiting holes 7, and the movable plate 5 is provided with a socket 701 coaxially arranged with the limiting hole 7. The movable plate 5, the limiting plate 3 and the anchoring plate 4 are limited by a pin 702 passing through the limiting hole 7 and the socket 701.

[0060] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for constructing large-volume high-support prestressed concrete beams, characterized in that: The following steps are involved: S1: Construction preparation work: erecting high supports, installing formwork, and tying steel bars; S2: Preset a full-length steel wire rope in the reserved channel for prestressed steel strands, install a steel strand anchoring mechanism on the entrance side of the reserved channel, and install a limit plate on the exit side of the reserved channel. Wherein, the steel strand anchoring mechanism comprises: an anchoring plate fixedly mounted on the entrance side of the reserved channel, a plurality of first through holes for passing the steel strands are circumferentially provided on the anchoring plate with the axis of the anchoring plate as the center, a movable plate is detachably fixedly mounted on the anchoring plate near the exit side of the reserved channel, the movable plate comprises a connecting portion detachably connected to the anchoring plate and a traction portion detachably connected to the connecting portion, a second through hole corresponding to the first through hole is provided on the connecting portion, a plurality of clamping pieces for clamping the steel strands that can slide along the radial direction of the second through hole are installed in the second through hole with the axis of the second through hole as the center; Passing multiple steel strands through the first through hole and the second through hole respectively, clamping and fixing the steel strands with the clamping pieces, and then connecting the steel wire ropes preset in the reserved channels to the traction part; S3: Preset a mark at the corresponding length of the steel strand extending from the movable plate according to the length of the reserved channel; S4: Pull the steel wire rope through the traction mechanism until the movable plate and the limit plate are matched, and adjust the marks on the steel strand to the same plane; S5: Cut the steel strands outside the reserved pipe near the anchor plate, install movable plates, and tension the movable plates on both sides of the steel strands to a preset elongation value; S6: After the tensioning is completed, grouting is performed in the reserved channel and concrete is poured to form the beam body; A cavity corresponding to the second through hole is provided in the connecting portion, and a limiting column extending into the cavity is fixedly connected to the clamping piece. The clamping piece can slide in a limited radial direction of the second through hole through the limiting column. A gear is rotatably installed in the cavity. The gear is coaxially fixedly connected to a screw, and the screw is threadedly connected to the limiting column. Rotating the screw can make the limiting column slide. A toothed disc is rotatably installed in the cavity, and the toothed disc is engaged with a plurality of gears. When installing the steel strand, the steel strand is passed through the second through hole, and the toothed disc is rotated to allow the multiple gears to slide synchronously, so that the holding piece clamps the steel strand.

2. The method for constructing a large-volume, high-support prestressed concrete beam according to claim 1, characterized in that: The outer circumferential wall of the gear disc is sleeved with a first gear ring, and a plurality of second gear rings are rotatably mounted in the connecting portion and mesh with the first gear rings arranged along the same circumference; When installing the steel strands, after all the steel strands are passed through the second through holes, the second gear ring is rotated so that the clamping pieces in the second through holes clamp the steel strands.

3. The method for constructing a large-volume, high-support prestressed concrete beam according to claim 2, characterized in that: The connecting part is provided with an arc-shaped limiting hole which is consistent with the curvature of the second gear ring, and the second gear ring is installed with an arc-shaped limiting plate which can extend out of the arc-shaped limiting hole, and the arc-shaped limiting plate slides in the arc-shaped limiting hole, and the traction part is provided with a slot which cooperates with the arc-shaped limiting plate, and the connecting part is provided with a threaded hole, and the traction part is threadedly connected to the threaded hole. After the traction part slides into the threaded hole along the arc-shaped limiting plate through the slot, rotating the traction part can rotate the second gear ring so that the clamping piece clamps the steel strand and the traction part can be threadedly fixed to the connecting part.

4. The method for constructing a large-volume, high-support prestressed concrete beam according to claim 3, characterized in that: The arc-shaped limit plate is slidingly connected to the second gear ring, an empty slot is provided in the arc-shaped limit plate, a limit block that can extend into the empty slot is installed on the second gear ring, and a spring is connected between the limit block and the inner wall of the empty slot.

5. The method for constructing a large-volume, high-support prestressed concrete beam according to claim 4, characterized in that: The anchor plate is threadedly connected with a threaded sleeve, and the threaded sleeve is provided with the first through hole; After passing through the first through hole, the steel strand can slide freely along the first through hole. When the movable plate drives the steel strand to move until the movable plate and the limit plate are fixed, the threaded sleeve is fixed to the steel strand so that the steel strand cannot slide along the first through hole. At this time, rotating the threaded sleeve can adjust the position of the steel strand so that the marks on the steel strand are in the same plane.

6. The method for constructing a large-volume, high-support prestressed concrete beam according to claim 5, characterized in that: The limiting plate and the anchoring plate are both provided with limiting holes, and the movable plate is provided with a socket coaxially arranged with the limiting hole; Before installing the steel strand, the movable plate and the anchor plate are fixed by means of a pin. At this time, the first through hole and the second through hole are connected to form a movable channel for the steel strand. After the steel strand is passed through the first through hole and out of the second through hole, the pin between the movable plate and the anchor plate is taken out, and the steel wire rope is pulled by the traction mechanism until the movable plate cooperates with the limit plate, and then the limit plate and the movable plate are fixed by the pin.

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