A device for threading and tensioning steel strands of a stayed cable and a construction method thereof

Abstract

The present invention relates to the technical field of cable-stayed bridge construction, and discloses a device for threading and tensioning anchoring of cable-stayed steel strands and a construction method thereof, comprising a traction system and a tensioning anchoring system, wherein the traction system is installed on both sides of the bridge tower, connecting the bridge tower and the main beam, and comprises a fixed cableway, a traction rope and a support plate; the tensioning anchoring system is installed on the main beam, and comprises an anchor, a temporary tool anchor, a tensioning pedestal, a temporary anchor hole and a clip; the traction system pulls the steel strands to be transmitted between the main beam and the bridge tower through the support plate, and can greatly improve the efficiency and accuracy of the cable threading in conjunction with the cable threading system; the guide rod and the guide rope can effectively avoid the misalignment phenomenon when the steel strands are threaded and anchored; the tensioning anchoring system can accurately and efficiently anchor the steel strands to the main beam, reduce the loss of tensioning prestress, and ensure that the stress of the cable-stayed steel strands is evenly distributed; the device and method of the present invention have simple structure, flexible operation, strong safety, high degree of automation, and wide application range, and can effectively avoid various problems existing in the threading of steel strands.

Description

Technical Field

[0001] The present invention relates to the technical field of cable-stayed bridge construction, and in particular to a stay cable steel strand threading and tensioning anchoring device and a construction method. Background Art

[0002] Stay cables are one of the primary load-bearing components of cable-stayed bridges. Depending on their material composition, they can be divided into parallel steel cables and stranded steel cables. Stranded steel cables are widely used in modern cable-stayed bridge construction due to their ease of construction, high efficiency, excellent corrosion resistance, and ease of replacement of individual strands. The cable force and shape of the stay cables directly influence the internal force distribution and operating conditions of the entire bridge. Ensuring the accuracy of cable construction and tensioning is crucial for controlling cable force.

[0003] In existing engineering cases, the cable-stayed cables are often cut and anchored at the bridge towers, which easily leads to stress concentration at the towers and is not conducive to uniform stress control of the cable-stayed cables. In addition, the cable-threading process of the steel strand cable-stayed cables is complicated. The main process is: using a tower crane or winch to lift the steel strand to the anchor point of the bridge tower, and then manually threading the steel strand from the high bridge tower end to the low main beam end. Due to the spiral spatial characteristics of the steel strand, the above process will have problems such as wall contact, bending, and entanglement during the cable-threading process. When the steel strands of the cable body are dense in the later stage of cable threading, the space for the steel strands to pass through is small, and there will also be problems of getting stuck midway, which will lead to high equipment consumption, high labor costs, long construction period, and high safety risks.

[0004] With the increasing number of wide-span cable-stayed bridges being built, more and more are adopting double-span cable planes to improve their lateral stiffness and stability. Ensuring uniform lateral force during cable tensioning in double-span cable-stayed bridges has become a challenge in this field. Furthermore, the cable-stayed cable has a large number of strands, while existing anchorages have densely packed anchor holes, limiting the space available for tensioning. This can easily result in insufficient or partially missing points of force for equipment such as tensioning jacks, leading to insufficient tensioning force or uneven stress distribution within a single strand of the cable, increasing the likelihood of cable replacement during service.

[0005] In summary, to ensure the accuracy of stay cable construction, it is necessary to improve the existing cable threading and tensioning anchoring devices and processes. To address this, a stay cable strand threading and tensioning anchoring device and construction method are proposed. By combining a threading system with a traction system to complete strand threading, and using a tensioning anchoring system to further improve strand tensioning quality, this approach is crucial for automating stay cable tensioning, improving construction control accuracy, and reducing construction safety risks. Summary of the Invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and provide a cable-stayed cable steel strand threading and tensioning anchoring device and a construction method thereof that have a simple structure, flexible operation, a high degree of automation, strong safety, and a wide range of applications, so as to solve problems such as wall contact, bending, entanglement, and midway jamming during the cable-stayed cable threading process, the problem of misalignment of the steel strands when passing through the anchor, and the problem of insufficient tensioning force and uneven tensioning of the steel strands in the cable-stayed cable.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A device for threading and tensioning anchorage of steel strands of a stayed cable comprises two traction systems and two tensioning anchorage systems. The upper end of each traction system is mounted on a bridge tower, and the lower end is mounted on the main beams on both sides of the bridge tower; the two tensioning anchorage systems are mounted on the main beams on both sides of the bridge tower, corresponding to the positions of the lower ends of the traction systems.

[0009] Preferably, the traction system includes a fixed cableway, a traction rope, a guide pulley, and a support plate:

[0010] One end of the fixed cableway is mounted on the bridge tower, and the other end is mounted on the main beam or the pre-buried positioning casing of the main beam;

[0011] There are two groups of guide pulleys, one group of guide pulleys is installed on the bridge tower, and the other group of guide pulleys is installed on the main beam or the positioning casing;

[0012] The traction rope is installed between the two sets of guide pulleys and is driven by a winch to reciprocate between the two sets of guide pulleys;

[0013] One side of the support plate is mounted on the fixed cableway, and the other side is detachably fixed to the traction rope. The middle part of the support plate is provided with a connection structure that is movably connected to the steel strand. The support plate drives the steel strand through the traction of the traction rope to realize the transmission between the bridge tower and the main beam.

[0014] Preferably, the tension anchoring system includes an anchor, a temporary tool anchor, and a tensioning pedestal:

[0015] The anchor is installed in the positioning casing, and the temporary tool anchor is installed at the tail end;

[0016] The tensioning pedestal is hollow inside, with through holes on the upper and lower end surfaces and slots on the side surfaces; a temporary anchor hole is provided in the through hole on the upper end surface of the tensioning pedestal, and the temporary anchor hole is movably connected to the temporary tool anchor; a jack is installed on the lower end surface of the tensioning pedestal;

[0017] After passing through the positioning casing, the steel strand is passed through the anchor, temporary tool anchor, temporary anchor hole, tensioning pedestal and jack in sequence, and the steel strand is temporarily fixed in the temporary anchor hole by using a clip.

[0018] Preferably, the temporary tool anchor is provided with anchor holes, the number and arrangement of the anchor holes are the same as the number and arrangement of the anchor holes in the anchor device, the spacing of the anchor holes in the temporary tool anchor is R times the spacing of the anchor holes in the anchor device, R is 1.2-1.5, preferably 1.3-1.4.

[0019] Preferably, a guide rope is passed through the anchor hole of the anchor, and one end of the guide rope is provided with a thread that is screwed to a guide rod provided at the end of the steel strand.

[0020] Preferably, a split-wire tube type saddle is installed on the bridge tower.

[0021] Preferably, the support plate transports the steel strand back and forth between the wire-distributing tube saddle and the positioning casing.

[0022] Preferably, a device for threading and tensioning and anchoring the steel strands of a cable-stayed cable also includes a cable threading system, wherein the cable threading system includes a cable threading machine and a conduit, and the conduit is installed on the top of the positioning casing; the steel strands are conveyed to the support plate under the push of the cable threading machine, and then installed on the support plate, and the steel strands are conveyed from the main beam at the transmission end to the wire-braiding tube-type cable saddle mouth under the dual power action of the cable threading system and the traction system, and then conveyed to the main beam at the receiving end after passing through the wire-braiding tube-type cable saddle.

[0023] Preferably, a guide rod is provided at each end of each steel strand, and the guide rod is provided with a thread; each steel strand is pushed out by the cable threading system and sent to two sets of tensioning and anchoring systems through the traction system, and the guide rods at both ends of the steel strand are respectively threaded with the guide cables installed in the anchor holes with the same numbers in the two sets of anchors.

[0024] As a preferred method, a construction method for stranding and tensioning stay cable steel strands, when applied to a single-cable-plane cable-stayed bridge, comprises the following steps:

[0025] S1. Installation of cable threading system, traction system and tensioning anchoring system:

[0026] Two tensioning anchorage systems were installed on the main beams on both sides of the pylons according to the designed anchorage positions of the stay cables. A cable threading system was installed near one of the tensioning anchorage systems. The lower ends of the two traction systems were installed on the main beams on both sides of the pylons, corresponding to the positions of the tensioning anchorage systems. The upper ends of the two traction systems were installed on both sides of the cable saddles installed on the pylons.

[0027] S2. Steel strand traction construction:

[0028] A guide rod is installed at each end of the i-th (i≥2) steel strand. A cable threading machine pushes the strand to a support plate in the traction system and connects it to the support plate. A winch drives the support plate and the strand to the outlet of the split-wire tubular saddle. The strand is then passed through the i-th cable hole corresponding to the split-wire tubular saddle to the other side of the bridge tower. After connecting to a support plate of another traction system, the strand is delivered to the main beam on the other side of the bridge tower.

[0029] S3. Steel strand anchoring and tensioning anchoring:

[0030] Screw the pilot rods at both ends of the i-th (i≥2) strand to the pilot cables in the i-th anchor hole of the anchorage in the tensioning anchorage system on both sides of the bridge tower. Pull the pilot cables to pass the strand under the anchorage. Use temporary tool anchors, tensioning pedestals, and jacks to tension the i-th (i≥2) strand simultaneously and in stages at both ends. During the tensioning process, clips are clamped into the temporary anchor holes to temporarily secure the strand. After tensioning is completed, the clips are inserted into the i-th anchor hole of the anchorage to form the final anchorage.

[0031] S4. Cable-threading construction:

[0032] Repeat steps S2-S3, tensioning the i+1th, i+2th, and last strands in sequence to complete the construction of the stay cable.

[0033] Preferably, the device and construction method for bundling and tensioning and anchoring the steel strands of the inclined cable described in the present invention are applied to the construction of a double-cable-plane cable-stayed bridge, using two sets of cable-threading systems, four sets of traction systems and four sets of tensioning and anchoring systems. The two sets of traction systems on the same side of the bridge tower share a set of traction ropes, which are driven by the same winch. The position of the support plate is continuously adjusted during the traction of the steel strands, so that the i-th (i-≥2) steel strands of the corresponding j-th (j≥1) inclined cable on the double cable planes are bundled simultaneously or alternately at the main beam end. After the bundling is completed, the i-th steel strands corresponding to each of the double cable planes are tensioned and anchored simultaneously at both ends of the main beam.

[0034] Beneficial effects

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The use of a traction system can avoid the problems of insufficient power, wall contact, bending, entanglement, and midway jamming of the steel strands in the existing technology during the stranding process. The use of a cable threading machine in conjunction with the traction system can greatly improve the stranding efficiency and quality of the inclined cable strands.

[0037] (2) The guide rod and the guide rope are used together, so that the steel strands will not be misaligned between the anchor hole and the wire-distributing tube saddle hole during the bundle threading process, and efficient and accurate bundle threading can be achieved.

[0038] (3) Adding a temporary tool anchor under the anchor to increase the tensioning space of the steel strand can effectively avoid the phenomenon of small or even missing jack points due to limited tensioning space in the existing technology; using temporary anchor holes and tensioning pedestals can further improve the tensioning environment of the steel strand and effectively ensure that each steel strand in the inclined cable reaches the design value in time and is evenly stressed;

[0039] (4) The device and method described in the present invention can realize the threading of the inclined cable from the lower end of the main beam to the higher end of the bridge tower. While greatly accelerating the construction progress, it can also improve the construction control accuracy and reduce labor costs and safety risks, making the entire threading and tensioning anchoring process simple to operate, with adjustable speed, automatic and light. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a general structural elevation diagram of an embodiment of the present invention;

[0041] Figure 2 (a) is a structural elevation view of the transmission end of an embodiment of the present invention, Figure 2 (b) Figure 2 Partial schematic diagram at point b in (a).

[0042] Figure 3 This is a structural elevation diagram of the receiving end according to an embodiment of the present invention.

[0043] Figure 4 Schematic diagram of the spatial point arrangement of the traction system of a single-cable-plane cable-stayed bridge according to an embodiment of the present invention.

[0044] Figure 5 This is a three-dimensional structural diagram of the traction system of a single-cable-plane cable-stayed bridge according to an embodiment of the present invention.

[0045] Figure 6 Schematic diagram of the support plate structure according to an embodiment of the present invention.

[0046] Figure 7 (a) is a schematic diagram of the guide rope threading and connection according to an embodiment of the present invention, Figure 7 (b) Figure 7 (a) Schematic diagram of the structure of the leader rope end and the leader rod.

[0047] Figure 8 This is a three-dimensional structural diagram of the tensioning and anchoring system according to an embodiment of the present invention.

[0048] Figure 9 (a) is a schematic diagram of an anchor and a temporary tool anchor according to an embodiment of the present invention, Figure 9 (b) is a schematic diagram of the tensioning platform and jack. Figure 9 (c) is a schematic diagram of the clip.

[0049] Figure 10 Schematic diagram of a split-wire tube saddle according to an embodiment of the present invention.

[0050] Figure 11 Schematic diagram of the spatial point arrangement of the traction system of a double-cable-plane cable-stayed bridge according to an embodiment of the present invention;

[0051] Figure 1 In Chinese: Ⅰ represents the transmitting end, Ⅱ represents the receiving end;

[0052] Figure 11 Middle: A represents cable surface A, B represents cable surface B;

[0053] Figures 1-11 In: (1) cable threading system; (11) cable threading machine; (12) catheter;

[0054] (2) Traction system; (21) Fixed ropeway; (22) Traction rope; (23) Support plate; (231) Temporary fixing device; (232) Groove; (233) Lug plate; (24) Guide pulley; (25) Winch; (26) Guide rod; (27) Guide rope;

[0055] (3) Tension anchor system; (31) Anchor; (32) Temporary tool anchor; (321) Finished rolled threaded steel bar; (322) Nut; (33) Tensioning pedestal; (331) Through hole; (332) Slotted hole; (333) Temporary anchor hole; (34) Clip; (35) Jack; (36) Clip vise;

[0056] (4) Stay cable; (41) Steel strand; (42) HDPE sheath;

[0057] (5) Main beam; (51) Positioning casing; (52) Reserved hole;

[0058] (6) Bridge tower; (61) Wire-type cable saddle;

[0059] (7) Bridge tower working platform. DETAILED DESCRIPTION

[0060] The present invention will be further described below with reference to the embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0061] It should be noted that the drawings are for illustrative purposes only and should not be construed as limiting this patent; in order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted; in the description of the present invention, unless otherwise clearly specified and limited, terms such as "installed", "connected", and "provided with" should be understood in a broad sense, and those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention under specific circumstances.

[0062] It should be noted that, in the description of the present invention, the directions or positional relationships indicated by directional words such as "upper", "lower", "upper end", "lower end", "above", "below", "one side", "the other side", "inside", etc. are usually based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention; unless otherwise specified, these directional words do not indicate or imply that the device or component referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0063] Example 1;

[0064] For the construction of cable 4 of a single-cable-plane cable-stayed bridge, see Figures 1-10 ;

[0065] The embodiment of the present invention provides a device for threading and tensioning and anchoring a stayed cable strand, comprising a threading system 1, two traction systems 2, and two tensioning and anchoring systems 3. The two traction systems 2 are respectively arranged on both sides of a bridge tower 6 (i.e., a transmission end I and a receiving end II), and their upper ends are both mounted on both sides of a wire-splitting tube-type saddle 61 on the bridge tower 6, and their lower ends are both mounted on the main beam 5, corresponding to the positioning casings 51 reserved on the main beam 5; the two tensioning and anchoring systems 3 are both mounted on the main beam 5, corresponding to the lower end positions of the traction systems 2; the threading system 1 is mounted on the main beam 5, corresponding to the lower end position of the traction system 2 at the transmission end I; the main beam 5 is further provided with a plurality of reserved holes 52, the reserved holes 52 being located between two adjacent positioning casings 51; a bridge tower working platform 7 is set up on both sides of the bridge tower 6 for threading the strands 41;

[0066] The traction system 2 includes a fixed cableway 21, a traction rope 22, a plurality of guide pulleys 24, and a support plate 23; one end of the fixed cableway 21 is installed on one side of the outlet of the wire tube saddle 61 on the bridge tower 6, and the other end is installed on the main beam 5 or the positioning casing 51; the guide pulley 24 is provided with two groups, one group is installed on the other side of the outlet of the wire tube saddle 61 on the bridge tower 6, and the other group is installed on the main beam 5 or the positioning casing 51; the traction rope 22 is installed between the two groups of guide pulleys 24 and the fixed cableway 21. The cableways 21 are arranged in a parallel and annular structure and are driven by a winch 25 installed on the main beam 5. The fixed cableway 21 and the traction rope 22 are respectively installed on the same side of the outlet of the branching tube saddle 61 and the positioning casing 51, so that the support plate 23 can move back and forth between the branching tube saddle 61 and the positioning casing 51, thereby transmitting the steel strand 41 between the branching tube saddle 61 and the positioning casing 51. A manual hoist or electric hoist is used to adjust the linear shape and tension of the fixed cableway 21 and the traction rope 22.

[0067] The support plate 23 is an arc-shaped steel plate, one side of which is provided with a group of upper and lower through holes, so that the support plate 23 can be mounted on the fixed cableway 21 for sliding; a group of ear plates 233 are welded to the upper and lower end surfaces of the other side of the support plate 23, and the traction rope 22 is detachably fixedly connected to the ear plates 233 by a lock; a circular groove 232 is opened in the middle of the support plate 23, and a temporary fixing device 231 corresponding to the groove 232 is provided. The temporary fixing device 231 is an arc-shaped thin steel plate, which is detachably connected to the support plate 23 by bolts. The temporary fixing device 231 cooperates with the groove 232 to realize the movable connection between the steel strand 41 and the support plate 23, thereby allowing the steel strand 41 to be transmitted along with the support plate 23 inside the HPDE sheath 42 between the bridge tower 6 and the main beam 5. The width of the support plate 23 is smaller than the inner diameter of the HDPE sheath 42;

[0068] The tensioning anchoring system 3 includes an anchor 31, a temporary tool anchor 32, a tensioning pedestal 33, a clip 34, a jack 35 and a clip vise 36. The anchor 31 is installed in the positioning casing 51. A plurality of anchor holes are provided inside the anchor 31. The number of anchor holes is consistent with the number of steel strands 41 in the inclined cable 4. A plurality of screw holes are provided on the periphery of the anchor 31. The temporary tool anchor 32 is installed at the tail end of the anchor 31 by means of fine-rolled threaded steel bars 321 and nuts 322. A plurality of anchor holes are provided on the temporary tool anchor 32. The number and arrangement of the anchor holes are the same as those on the anchor 31. The spacing of the anchor holes on the temporary tool anchor 32 is R times the spacing of the anchor holes inside the anchor 31. R is 1.2-1.5, preferably 1.3-1.4.

[0069] A pilot rod 26 is welded to each end of the steel strand 41, and a pilot cable 27 is screwed to one end of the pilot rod 26. The pilot cable 27 is installed in the anchor holes with the same number in the anchors 31 provided on the main beams 5 on both sides of the bridge tower 6; the pilot cable 27 enters the inner box of the main beam 5 from the reserved hole 52, and then passes through the temporary tool anchor 32 and the internal anchor hole of the anchor 31 to the top of the positioning casing 51, and then the pilot cable 27 is screwed to the pilot rod 26, and the pilot cable 27 is pulled to make the pilot rod 26 and the steel strand 41 pass through the positioning casing 51 and the anchor 31 to the bottom of the temporary tool anchor 32 in sequence;

[0070] The tensioning pedestal 33 has a cavity inside, and the upper and lower end surfaces are provided with through holes 331 with an inner diameter slightly larger than the diameter of the steel strand 41, and the side surfaces are provided with slots 332; the upper end surface of the tensioning pedestal 33 is provided with a temporary anchor hole 333, which is movably connected to the temporary tool anchor 32, and the lower end surface is installed with a jack 35; the steel strand 41 passes through the temporary tool anchor 32 and then passes through the temporary anchor hole 333, the tensioning pedestal 33 and the jack 35 in sequence, and the steel strand 41 is tensioned in stages by the tensioning pedestal 33 and the jack 35, and a clip 34 is installed into the temporary anchor hole 333 through the slot 332 of the tensioning pedestal 33 using a clip jaw pliers 36 to achieve temporary fixation of the steel strand 41;

[0071] The cable threading system 1 includes a cable threading machine 11 that provides thrust for the steel strand 41 and a conduit 12 that transfers the steel strand 41 to the traction system 2. The conduit 12 is a hollow semi-steel circular tube with an inner diameter larger than the diameter of the steel strand 41. The conduit 12 is installed at the top of the positioning casing 51. The steel strand 41 is transferred to the top of the positioning casing 51 under the push of the cable threading machine 11 and then installed on the support plate 23. Under the dual power of the traction system 2 and the cable threading machine 11, the steel strand 41 is transferred from the main beam 5 of the transmission end I to the outlet of the wire-distributing tube-type saddle 61 along with the support plate 23. After passing through the wire-distributing tube-type saddle 61, it is transferred to the main beam 5 of the receiving end II.

[0072] Example 2;

[0073] For the construction of cable 4 of a single-cable-plane cable-stayed bridge, see Figures 1-10 ;

[0074] The construction method of the stay cable steel strand threading and tensioning anchoring device of the present invention comprises the following steps:

[0075] S1. Installation of cable threading system, traction system and tensioning anchoring system:

[0076] Since the steel strand 41 needs to be installed in the HDPE sheath 42 during the construction of the inclined cable, before using the device described in the present invention to carry out the construction of the inclined cable, it is necessary to first complete the installation and positioning of the first steel strand 41 and the HDPE sheath 42 by using a tower crane. Before the first steel strand 41 is anchored, the anchor 31 must be installed inside the positioning casing 51, and then a temporary tool anchor 32 must be installed at the tail end of the anchor 31. Then, the anchoring and tensioning anchoring are carried out simultaneously in the main beam 5 of the transmitting end I and the main beam 5 of the receiving end II according to step S3;

[0077] After the construction of the first steel strand 41 is completed, two traction systems 2 are installed at the transmission end I and the receiving end II. The upper ends of the two traction systems 2 are installed on both sides of the wire-distributing tube saddle 61 on the bridge tower 6, and the lower ends are installed on the main beam 5 or the positioning casing 51. The cable threading system 1 is installed next to the positioning casing 51 at the transmission end I, and the guide tube 12 is installed on the top of the positioning casing 51.

[0078] S2. Steel strand traction construction:

[0079] S2-1. Construction of steel strand traction at the transmission end:

[0080] At the transmission end I, the i-th (i≥2) steel strand 41 is cut and a guide rod 26 is welded at both ends thereof. The cable threading machine 11 is started to deliver one end of the i-th steel strand 41 to the position above the positioning casing 51. At the same time, the support plate 23 is moved to the position above the positioning casing 51. Then, the i-th steel strand 41 is installed on the support plate 23 by means of the temporary fixing device 231 and screws. The hoist 25 of the transmission end I is started and cooperated with the cable threading machine 11 to pull the support plate 23 together with one end of the i-th steel strand 41 to the outlet of the branching tube type saddle 61 of the bridge tower 6. The construction personnel of the transmission end I remove one end of the i-th steel strand 41 from the support plate 23 on the bridge tower working platform 7, and then pass it from the transmission end I through the i-th cable hole corresponding to the branching tube type saddle 61 on the bridge tower 6 to the other side of the bridge tower 6, namely the receiving end II.

[0081] S2-2, Receiving end steel strand traction construction:

[0082] Construction workers at receiving end II receive the i-th steel strand 41 from the tower work platform 7 on the other side of the tower 6. Similarly, they install the i-th steel strand 41 on the support plate 23 of the traction system 2 of receiving end II using the temporary fixing device 231 and screws. Then, the winch 25 of receiving end II, in conjunction with the cable threading machine 11, delivers the i-th steel strand 41 along with the support plate 23 to just above the positioning casing 51 of receiving end II. The steel strand 51 is then removed from the support plate 23.

[0083] S3. Steel strand anchoring and tensioning anchoring:

[0084] S3-1, Steel Strand Anchor:

[0085] While carrying out steps S1-S3, a guide rope 27 is used to penetrate from the reserved hole 52 of the main beam 5 to the inner box of the main beam 5 at the transmission end I and the receiving end II, respectively. The construction workers of the inner box of the main beam 5 sequentially penetrate the guide rope 27 through the temporary tool anchor 32 and the i-th anchor hole corresponding to the anchor 31, and pass it out from the top of the positioning casing 51; after screwing the guide rope 27 with the corresponding guide rod 26, the construction workers of the inner box of the main beam 5 pull the guide rope 27, so that the i-th steel strand 41 passes through the positioning casing 51, the i-th anchor hole corresponding to the anchor 31 and the i-th anchor hole corresponding to the temporary tool anchor 32 in sequence, and is pulled to the bottom of the temporary tool anchor 32. After removing the guide rope 27, the temporary anchor hole 333, a set of tensioning pedestals 33 and the jack 35 are respectively assembled below the temporary tool anchor 32 at the transmission end I and the receiving end II;

[0086] S3-2. Tensioning and anchoring of single steel strand:

[0087] At the same time, the i-th steel strand 41 is tensioned in N stages at the transmission end I and the receiving end II. At the end of the n-th (1≤n<N) tensioning stage, a group of clips 34 are gradually hammered into the temporary anchor hole 333 using a clip jaw pliers 36 to clamp the i-th steel strand 41, thereby achieving temporary anchoring of the i-th steel strand 41. At the end of the N-th stage, that is, after the i-th steel strand 41 is tensioned to the design stress, a group of clips 34 are embedded into the i-th anchor hole of the anchor 31 using a clip jaw pliers 36 to form a final anchoring. The tensioning pedestal 33 and the jack 35 are removed, and the excess length of the steel strand 41 including the pilot rod 26 is cut, thereby completing the tensioning and anchoring of the i-th steel strand 41.

[0088] S4. Cable-threading construction:

[0089] Repeat steps S2-S3 to tension the (i+1), (i+2) to the last strand 41 in sequence to complete the construction of the bundle of stay cables 4, and then remove the temporary tool anchor 32.

[0090] By constructing the first, second, ..., jth, j+1th to the last bundle of stay cables 4 in sequence according to the above method, a single cable plane of the cable-stayed bridge can be formed.

[0091] Example 3;

[0092] For the construction of a double-cable-plane cable-stayed bridge, in order to ensure the lateral stability of the double-cable-plane cable-stayed bridge structure during the tensioning of the steel strands 41, the i-th (i≥2) steel strands 41 of the j-th (j≥1) bundle of the cable 4 at the corresponding position on the two sets of cable planes need to be bundled simultaneously or alternately, and then tensioned and anchored simultaneously;

[0093] See also Figure 1-Figure 3 and Figure 5-Figure 11The device uses two sets of cable threading systems 1, four sets of traction systems 2 and four sets of tensioning and anchoring systems 3. The two sets of traction systems 2 on the same side of the bridge tower 6 share the same set of traction ropes 22. The traction ropes 22 are connected to two supporting plates 23 on different cable planes (cable plane A and cable plane B) and are driven by the same set of winches 25. The guide pulleys 24 adopt a scheme that matches the traction ropes 22. The initial position of one supporting plate 23 is above the positioning casing 51 (i.e., on the main beam side), and the other is located above the positioning casing 51. The initial position of the support plate 23 is near the bridge tower 6 (i.e., the bridge tower side). When one support plate 23 moves from the main beam 5 side to the bridge tower 6 side, the other support plate 23 naturally moves from the bridge tower 6 side to the main beam 5 side. The support plate 23 moves back and forth between the outlet of the wire tube saddle 61 and the positioning casing 51, while driving the steel strand 41 to be transmitted between the two. This cycle is repeated, and the steel strands 41 on both cable planes can be bundled at the same time or alternately, thereby improving the bundle threading efficiency and quality of the double-cable-plane cable-stayed bridge.

[0094] The difference between this embodiment and the method described in embodiment 2 is that:

[0095] First, the steel strands 41 are bundled simultaneously or alternately according to step S2, and then tensioned and anchored according to step S3;

[0096] The simultaneous stranding process includes: two sets of cable threading systems 1 are installed on both sides of the bridge tower 6, and the two cable threading systems 1 cooperate with the four traction systems 2 to simultaneously thread and pull the steel strands 41 on both sides of the bridge tower 6 according to step S2. The position of the support plate 23 is continuously adjusted during the traction process. After the corresponding steel strands 41 on both cable surfaces are pulled, the four tensioning and anchoring systems 3 are simultaneously used to tension and anchor the two ends of the steel strands 41 according to step S3.

[0097] Alternating stranding involves two cable threading systems 1 installed on the same side of the bridge tower 6. The two cable threading systems 1 cooperate with four traction systems 2 to alternately thread and pull the steel strands 41 on the same side of the bridge tower 6 according to step S2. During the traction process, there is no need to adjust the position of the support plate 23. After the corresponding steel strands 41 on both cable surfaces are pulled, four tensioning and anchoring systems 3 are simultaneously used to tension and anchor the two ends of the steel strands 41 according to step S3.

[0098] By repeating the above method, the construction of all the steel strands 41 in the jth bundle of stay cables 4 corresponding to the double cable plane can be completed; by sequentially constructing the first, second, ..., jth, j+1th to the last bundle of stay cables 4 according to the above method, the double cable plane of the cable-stayed bridge can be formed.

[0099] Comparative Example 1;

[0100] The supporting project for this comparative example is a newly built double-tower, double-cable-plane cable-stayed bridge. The main girder adopts a single-box, three-chamber, variable-section prestressed concrete box girder. The main tower is arranged in the central median and is a column-type tower. The inclined cables 4 adopt a double-cable-plane arrangement. The inclined cables 4 are arranged in 23 groups, totaling 92 bundles. The specification of the inclined cables is 55Φ15.2mm single-filament epoxy-sprayed steel strand 41, and the standard strength of the steel strand 41 is 1860MPa.

[0101] The traditional construction method uses a single cable threading machine 11 in conjunction with manual threading, i.e., "passive" cable feeding. Its most obvious disadvantages are insufficient power and low degree of automation. The steel strands 41 of the inclined cables 4 may touch the wall, get entangled, or get stuck during the threading process, which prolongs the construction period. When the traditional cable threading method is applied to this bridge, the construction time of a single inclined cable 4 is about 72 hours under the condition of smooth operation. If the above-mentioned common problems are encountered, it will take at least 96 hours. If the tensioning device and process are not improved, the initial prestressing qualification rate of the steel strands 41 will be less than 80%, and a lot of time will be required for secondary tensioning or release of the steel strands 41.

[0102] Example 4;

[0103] This embodiment is based on the same cable-stayed bridge project as Comparative Example 1, and is constructed using the device and method described in the present invention. The materials and dimensions of the relevant structures are as follows:

[0104] The conduit 12 is a hollow semicircular steel tube with an outer diameter of 48 mm and a wall thickness of 3.5 mm;

[0105] The outer diameter of the support plate 23 is 200 mm, the wall thickness is 10 mm-12 mm, the width of the support plate 23 is approximately 1 / 3 of the circumference, the diameter of the groove 232 is 12 mm-15 mm, the diameter of the temporary fixing device 231 matches the groove 232, and is fixed with two bolts;

[0106] The fixed ropeway 21 and the traction rope 22 are both made of steel wire rope with a diameter of 3mm-5mm, and the horizontal distance between the two inside the HDPE sheath 42 is 150mm-180mm;

[0107] The reserved hole 52 has a diameter of 10mm-15mm and is located between two adjacent positioning casings 51 on the same cable surface;

[0108] The pilot rod 26 is a high-strength screw with good weldability and a length of about 20 cm, which can smoothly pass through the wire-splitting tube-type cable saddle 61. The pilot cable 27 is made of galvanized steel wire. The diameter of the pilot rod 26 thread and the inner thread of the pilot cable nut 27 are 3mm-5mm and match each other.

[0109] The temporary tool anchor 32 has the same structure as the anchor 31 in terms of the number and arrangement of anchor holes, and uses a 55-hole anchor plate. The cross-sectional area of the temporary tool anchor 32 is about 30% larger than that of the anchor 31, that is, the anchor hole spacing is about 1.3 times that of the anchor hole spacing of the anchor 31.

[0110] The temporary anchor hole 333 is made of a hollow round steel pipe with an inner diameter greater than or equal to 16 mm, a length of approximately 50 mm, and a wall thickness greater than or equal to 6 mm;

[0111] When the device and method described in the present invention are applied to this bridge, the construction time of a single inclined cable 4 on a double cable plane generally ranges from 36 hours to 48 hours, and the qualified rate of a single random inspection of the tensioning of the steel strands 41 is above 95%, that is, there is generally no need for re-tensioning or releasing; obviously, after adopting the device and method described in the present invention, the bundle threading efficiency is increased by about 1 times, and the tensioning quality of the steel strands 41 is greatly improved.

[0112] Matters not covered by the present invention are known technologies.

[0113] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for threading and tensioning and anchoring steel strands of a stay cable, characterized in that: It includes two traction systems and two tensioning and anchoring systems. The upper end of each traction system is installed on the bridge tower, and the lower end is installed on the main beams on both sides of the bridge tower; the two tensioning and anchoring systems are installed on the main beams on both sides of the bridge tower, corresponding to the lower end of the traction system; the main beams are pre-buried with positioning casings; The traction system includes a fixed cableway, a traction rope, a guide pulley, and a support plate; One end of the fixed cableway is mounted on the bridge tower, and the other end is mounted on the main beam or the pre-buried positioning casing of the main beam; There are two groups of guide pulleys, one group of guide pulleys is installed on the bridge tower, and the other group of guide pulleys is installed on the main beam or the positioning casing; The traction rope is installed between the two sets of guide pulleys and is driven by a winch to reciprocate between the two sets of guide pulleys; One side of the support plate is mounted on the fixed cableway, and the other side is detachably fixedly connected to the traction rope. A connection structure movably connected to the steel strand is provided in the middle of the support plate. The support plate drives the steel strand to be transported between the bridge tower and the main beam by the traction of the traction rope. The tension anchoring system includes an anchor, a temporary tool anchor, and a tensioning pedestal; The anchor is installed in the positioning casing, and the temporary tool anchor is installed at the tail end; The tensioning pedestal is hollow inside, with through holes on the upper and lower end surfaces and slots on the side surfaces; a temporary anchor hole is provided in the through hole on the upper end surface of the tensioning pedestal, and the temporary anchor hole is movably connected to the temporary tool anchor; a jack is installed on the lower end surface of the tensioning pedestal; After passing through the positioning casing, the steel strand is passed through the anchor, temporary tool anchor, temporary anchor hole, tensioning pedestal and jack in sequence, and the steel strand is temporarily fixed in the temporary anchor hole by using a clip; The temporary tool anchor is provided with anchor holes, the number and arrangement of the anchor holes are the same as the number and arrangement of the anchor holes in the anchor device, the spacing of the anchor holes in the temporary tool anchor is R times the spacing of the anchor holes in the anchor device, and R is 1.2-1.

5.

2. The device for threading and tensioning and anchoring the steel strands of a stayed cable according to claim 1, characterized in that: A guide rope is passed through the anchor hole of the anchor, and one end of the guide rope is provided with a thread which is screwed to a guide rod arranged at the end of the steel strand.

3. A stay cable steel strand threading and tensioning anchoring device according to any one of claims 1-2, characterized in that: A split-wire tubular cable saddle is installed on the bridge tower.

4. The device for threading and tensioning and anchoring the steel strands of a stayed cable according to claim 3, characterized in that: The supporting plate transports the steel strands back and forth between the wire-distributing tube-type saddle and the positioning casing pre-buried in the main beam.

5. The device for threading and tensioning and anchoring the steel strands of a stayed cable according to claim 4, characterized in that: It also includes a cable threading system, which includes a cable threading machine and a catheter, and the catheter is installed on the top of the positioning casing; the steel strand is transmitted to the support plate under the push of the cable threading machine, and then installed on the support plate. Under the dual power of the cable threading system and the traction system, the steel strand is transmitted from the main beam at the transmission end to the wire-dividing tube-type cable saddle mouth, and then transmitted to the main beam at the receiving end after passing through the wire-dividing tube-type cable saddle.

6. A stay cable steel strand threading and tensioning anchoring device according to claim 5, characterized in that: Each steel strand is provided with a pilot rod at both ends, and the pilot rod is provided with a thread; each steel strand is pushed out by the cable threading system and sent to two sets of tensioning and anchoring systems through the traction system. The pilot rods at both ends of the steel strand are respectively threaded with the pilot cables installed in the anchor holes with the same numbers in the two sets of anchors.

7. A method for bundling and tensioning stay cable strands, using the device for bundling and tensioning stay cable strands as claimed in claim 6, when applied to a single-cable-plane cable-stayed bridge, comprising the following steps: S1. Installation of cable threading system, traction system and tensioning anchoring system: According to the designed anchorage positions of the stay cables, two tensioning anchorage systems are installed on the main beams on both sides of the bridge tower. A cable threading system is installed near the location of one of the tensioning anchorage systems. The lower ends of the two traction systems are installed on the main beams or positioning casings on both sides of the bridge tower, corresponding to the locations of the tensioning anchorage systems. The upper ends of the two traction systems are installed on both sides of the wire-type cable saddles installed on the bridge tower. S2. Steel strand traction construction: A guide rod is installed at each end of the i-th (i≥2) strand. A cable threading machine pushes the strand to a pallet in the traction system and connects it to the pallet. A winch drives the pallet and the strand to the outlet of the split-wire tubular saddle. The strand is then passed through the i-th cable hole corresponding to the split-wire tubular saddle to the other side of the bridge tower. After connecting to a pallet in another traction system, the strand is delivered to the main beam on the other side of the bridge tower. S3. Steel strand anchoring and tensioning anchoring: Screw the pilot rods at both ends of the i-th (i≥2) strand to the pilot cables in the i-th anchor hole of the anchorage in the tensioning anchorage system on both sides of the bridge tower. Pull the pilot cables to pass the strand under the anchorage. Use temporary tool anchors, tensioning pedestals, and jacks to tension the i-th (i≥2) strand simultaneously at both ends in stages. During the tensioning process, clips are installed in the temporary anchor holes to temporarily secure the strand. After tensioning is completed, the clips are inserted into the i-th anchor hole of the anchorage to form the final anchorage. S4. Cable-threading construction: Repeat steps S2-S3, tensioning the i+1th, i+2th, and last strands in sequence to complete the construction of the stay cable.

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