Construction method of efficient cable changing system of multi-tower cable-stayed bridge

Abstract

The invention relates to a construction method of an efficient cable changing system of a multi-tower cable-stayed bridge, which adopts a technology of supporting steel pipes between tower columns to assist in hanging and releasing stay cables, effectively improves the construction safety and efficiency, adapts to severe environment construction, remarkably improves the stress performance and reduces the construction risk. By the adoption of the old stay cable tower end staged tension releasing technology, accurate control and safe operation in the old stay cable dismounting process are achieved, through staged tension releasing, the construction risk is effectively reduced, the construction efficiency is improved, and meanwhile the stability and safety of a bridge structure are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, and in particular relates to a construction method for an efficient cable replacement system of a multi-tower cable-stayed bridge. Background Art

[0002] With the rapid development of economy, the mileage of highways is increasing. As an important part of highway engineering, the cable-stayed bridge is crucial to the structural stability and driving safety. During the operation of bridges, the cable-stayed bridge is easily affected by the shrinkage and creep of concrete, the impact of external loads, and natural climate and environmental factors, resulting in damage, which affects the comfort and safety of vehicles.

[0003] The traditional method of replacing cable-stayed bridges is time-consuming, affects traffic flow, and cannot meet the current traffic needs. Therefore, it is very important and necessary to develop technology for efficiently and quickly replacing cables of multi-tower cable-stayed bridges. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a construction method for an efficient cable replacement system of a multi-tower cable-stayed bridge.

[0005] The construction method of the multi-tower cable-stayed bridge high-efficiency cable replacement system comprises the following steps:

[0006] Step 1: Then remove the built-in shock absorber of the tower end cable guide, connect the connecting sleeve and the old cable anchor cup, and tension the old cable tower end in three stages;

[0007] Step 2: Set a traction point on the beam surface corresponding to the beam end of the old cable, and lift the lifting belt; start to release the beam end, and use the bridge deck winch to pull the old cable anchor cup nut away from the anchor pad; loosen the old cable anchor cup toward the tower column until it is completely free of stress;

[0008] Step 3: Use the tower top hanger to hoist the first winch to the tower top, install several rows of steel pipe supports from bottom to top between the tower columns to assist in hoisting the cable-stayed platform, and use the first winch and steel pipe supports at different heights to assist in hoisting the second winch on the cable-stayed platform to hoist the old cable removed from the tower end;

[0009] Step 4: Install new stay cables.

[0010] Preferably, the tensioning equipment and the first winch in the tower are hoisted to the top of the tower by using the tower top hanger. The tensioning equipment in the tower includes: tensioning rod, tensioning rod nut, jack, tensioning support foot, connecting sleeve, jack cylinder, auxiliary tensioning rod, auxiliary tensioning rod nut, tensioning rod auxiliary nut, pad, first tool anchor and pressure plate, second tool anchor and pressure plate, soft traction connector and tower end construction basket; after positioning and fixing the first winch, the tensioning equipment is hoisted into the tensioning position in the tower by using the first winch, the first lifting rope and the first lifting hook, the tower top hanger is used as a fixed point, the tower end construction basket is installed, and then the built-in shock absorber of the tower end cable guide tube is removed, and the rust on the old cable anchor cup and the old cable anchor cup nut is cleaned, and the connecting sleeve and the thread inside the old cable anchor cup are adapted.

[0011] Preferably, in step one, in the first stage of tensioning the tower end of the old inclined cable, the tensioning and tensioning equipment is installed in the order of the connecting sleeve, tension rod, tension support foot, jack and tension rod nut, the tension rod nut is screwed away from the jack cylinder for a certain distance, the jack supplies oil to make the tension rod nut stressed, and after the old cable anchor cup nut is detached from the anchor plate, the old cable anchor cup nut is screwed away from the anchor plate for a certain distance, the two sets of tensioning equipment in the tower are graded and symmetrically returned to oil as required until the old cable anchor cup nut is pressed onto the anchor plate, the above steps are repeated for tensioning until the old cable anchor cup nut is screwed to the flat cap, and the first stage of tensioning is completed.

[0012] As a preferred method. In step one, the second stage of tensioning the old cable tower end is performed by a single-sided tensioning method. The tensioning system of the first stage of tensioning the old cable tower end is dismantled, the auxiliary tension rod nut and the auxiliary tension rod are installed, and the tensioning system is reassembled. The auxiliary tension rod nut is rotated away from the jack cylinder for a certain distance, the jack supplies oil, and the cylinder extends a certain distance to make the auxiliary tension rod nut stressed. The old cable anchor cup nut is rotated away from the old cable anchor cup, and the jack returns oil, so that the tension rod auxiliary nut acts on the old cable anchor cup nut. When the tension rod auxiliary nut cannot act on the anchor plate due to the length of the connecting sleeve, a pad is set between the old cable anchor cup nut and the tension rod auxiliary nut, and the above steps are repeated for tensioning until the tension rod auxiliary nut is rotated to a flat cap state, and the second stage of tensioning is completed.

[0013] Preferably, in step one, in the third stage of tensioning the old cable tower end, the first tool anchor and pressure plate are installed after the jack cylinder is extended a certain distance, and the jack continues to supply oil. The first tool anchor and pressure plate are stressed to make the tension rod sub-nut separate from the old cable anchor cup nut. At the same time, the force on the steel strand is evenly adjusted, the tension rod sub-nut is removed, and the jack returns oil to make the second tool anchor and pressure plate act on the tension rod sub-nut. When the remaining stroke of the jack cylinder is less than or equal to 20 mm, the second tool anchor and pressure plate are installed, and the oil is continued to be returned to make the second tool anchor and pressure plate stressed, and the first tool anchor and pressure plate are removed. The above steps are repeated until the old cable anchor cup at the tower end is lowered a certain distance and the tension force at the beam end is less than 30t.

[0014] Preferably, in step 2, a traction point is set on the beam surface near the beam end of the old inclined cable to bear force, and a set of three-door pulleys is fixed with a U-shaped clamp as a fixed pulley; traction points are set on the old inclined cable at different positions from the cable guide tube using soft lifting belts, and a set of single-door pulleys is installed on each traction point as a movable pulley; the steel wire rope is installed between the fixed pulley and the movable pulley, and the bridge deck winch is used as the traction power, and a soft lifting belt is set at the rear end of the traction point on the old inclined cable, and the lifting belt is lifted by the car crane; the beam end is started to be released, and the lifting belt is lifted by the car crane. The winch on the bridge deck pulls the nut of the old cable anchor cup off the anchor pad; the nut of the old cable anchor cup at the beam end is removed, and the traction system of the bridge deck winch at the beam end is loosened to make the anchor cup at the beam end exit the cable guide tube, and continue to loosen it until the winch traction system is no longer stressed; the bridge deck winch releases the bridge deck pull rope to release the old cable anchor cup out of the cable guide tube. During the whole process, a truck crane is used to adjust the angle of the old cable anchor cup and the tensioning rod out of the cable guide tube; the truck crane is continued to be used to lift the cable body, and the bridge deck winch releases the bridge deck pull rope to loosen the old cable anchor cup toward the cable tower column until it is completely free of stress, and the tensioning of the bridge deck winch at the beam end is completed.

[0015] Preferably, in step three, the first winch, the first lifting rope and the first hook are hoisted to the top of the tower by the tower top hanger, and five rows of steel pipe support auxiliary cable-stayed cable platforms are installed in sequence from bottom to top between the tower columns. The second winch, the first lifting rope and the first hook are respectively hoisted to each row of steel pipe support auxiliary cable-stayed cable platforms by the first winch, the first lifting rope and the first hook. When the old cable-stayed cables removed from the tower end are hoisted downward to the corresponding steel pipe support auxiliary cable-stayed cable platforms by the first winch, the first lifting rope and the first hook, they are replaced with the second winch, the second lifting rope and the second hook on the corresponding steel pipe support auxiliary cable-stayed cable platforms to hoist the old cable-stayed cables. The old cable-stayed cables on the bridge deck are moved by pulling the cable-unfolding trolley with the bridge deck winch and the bridge deck pull rope.

[0016] Preferably, step four includes hanging the new cable tower end, laying out the new cable beam surface, pulling the new cable beam end, soft pulling of the steel strands at the new cable tower end, hard pulling and tensioning of the new cable tower end, and the order of hoisting the tower end of the new cable is opposite to that of the old cable.

[0017] An efficient cable replacement system for a multi-tower cable-stayed bridge is obtained by any of the above-mentioned methods.

[0018] The beneficial effects of the present invention are:

[0019] 1) The present invention adopts the technology of supporting steel pipes between tower columns to assist in the hanging of inclined cables, which effectively improves the construction safety and efficiency, adapts to construction in harsh environments, significantly improves the stress performance, and reduces construction risks.

[0020] 2) The present invention adopts the technology of releasing the old cable towers in stages, which realizes precise control and safe operation during the dismantling process of the old cable. By releasing the cables in stages, the construction risks are effectively reduced, the construction efficiency is improved, and the stability and safety of the bridge structure are ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the tension rod nut being rotated a certain distance away from the jack cylinder during the first stage of the tower end tensioning;

[0022] Figure 2 This is a schematic diagram of the old cable anchor cup nut being detached from the anchor pad during the first stage of tower end placement;

[0023] Figure 3 This is a schematic diagram of the first stage of placing the old cable anchor cup nut on the anchor pad at the tower end;

[0024] Figure 4 This is a schematic diagram of the first stage of placing the old cable anchor cup nut in the tower end and screwing it to the flat cap;

[0025] Figure 5 It is a schematic diagram of the auxiliary tension rod nut being rotated a certain distance away from the jack cylinder during the second stage of placing the tower end;

[0026] Figure 6 This is a schematic diagram of the second stage of placing the old cable anchor cup in the tower end and unscrewing the nut from the old cable anchor cup;

[0027] Figure 7 It is a schematic diagram of setting a pad between the old cable anchor cup nut and the tension rod auxiliary nut during the second stage of tensioning at the tower end;

[0028] Figure 8 This is a schematic diagram of the tower end tensioning tie rod auxiliary nut being screwed to the flat cap state during the second stage of tensioning;

[0029] Fig. 9 This is a schematic diagram of the detachment of the auxiliary nut of the tension rod from the old cable anchor cup nut during the third stage of the tower end tensioning;

[0030] Fig.10 This is a schematic diagram of the third stage of the tower end, in which the old cable anchor cup at the middle tower end is lowered a certain distance;

[0031] Fig.11 This is a schematic diagram of the construction structure of the tower end construction hanging basket;

[0032] Fig.12 This is a schematic diagram of the structure of the old cable-stayed cables assisted by the steel pipe bracing between the tower columns;

[0033] Fig.13 It is the plan layout of the efficient cable replacement deck construction of a multi-tower cable-stayed bridge;

[0034] Fig.14It is a schematic diagram of the new cable-stayed structure that is assisted in hoisting by steel pipe bracing between tower columns.

[0035] In the figure: 1-tower column, 2-bridge deck, 3-first pair of supporting steel pipes, 4-embedded parts for installing the pair of supporting steel pipes, 5-first auxiliary lifting construction platform, 6-first guardrail, 7-second pair of supporting steel pipes, 8-second auxiliary lifting construction platform, 9-second guardrail, 10-third pair of supporting steel pipes, 11-third auxiliary lifting construction platform, 12-third guardrail, 13-fourth pair of supporting steel pipes, 14-fourth auxiliary lifting construction platform, 15-fourth guardrail, 16-fifth pair of supporting steel pipes, 17-fifth auxiliary lifting construction platform, 18-fifth guardrail, 19-tower top hanger, 20-lightning rod, 21-first winch, 22-first lifting rope, 23-first hook, 24-second winch , 25-second lifting rope, 26-second lifting hook, 27-old inclined cable, 28-cable extension trolley, 29-new inclined cable, 30-bridge winch, 31-bridge rope, 32-tension rod, 33-tension rod nut, 34-jack, 35-tensioning support foot, 36-connecting sleeve, 37-old cable anchor cup, 38-old cable anchor cup nut, 39-jack cylinder, 40-anchor pad, 41-secondary tension rod, 42-secondary tension rod nut, 43-tension rod secondary nut, 44-pad, 45-steel strand, 46-built-in shock absorber of tower end cable guide, 47-first tool anchor and pressure plate, 48-second tool anchor and pressure plate, 49-soft traction connector, 50-tower end construction hanging basket. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for ordinary persons in the art, without departing from the principle of the present invention, the present invention can also be modified in some ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0037] Embodiment 1

[0038] As an embodiment, the main construction process of the construction method of the multi-tower cable-stayed bridge high-efficiency cable replacement system is as follows:

[0039] Step 1, the tower end of the old inclined cable 27 is tensioned in stages: the tensioning equipment and the first winch 21 in the tower are hoisted to the top of the tower by the tower top hanger 19, and after the first winch 21 is positioned and fixed, the tensioning equipment is hoisted into the tensioning position in the tower by the first winch 21, the first hoisting rope 22, and the first hook 23, and the tower top hanger 19 is used as a fixed point to install the tower end construction hanging basket 50, and then the built-in shock absorber 46 of the tower end cable guide is removed, and the rust of the old cable anchor cup 37 and the old cable anchor cup nut 38 are cleaned, and the connecting sleeve 36 is adapted to the inner thread of the old cable anchor cup 37 to ensure that the connecting sleeve 36 can be connected to the old cable anchor cup 37; the tensioning of the tower end of the old inclined cable 27 is divided into the first stage of the tensioning of the tower end of the old inclined cable 27, the second stage of the tensioning of the tower end of the old inclined cable 27, and the third stage of the tensioning of the tower end of the old inclined cable 27.

[0040] Step 2, tensioning and removal of the old inclined cable 27 and the bridge winch 30 at the beam end: a traction point is set on the beam surface near the beam end of the old inclined cable 27 to bear force, and a set of three-door pulleys are fixed with a U-shaped clamp as a fixed pulley; three traction points are set on the cable body at 2m, 4m and 6m away from the cable guide tube using a soft lifting belt, and a set of single-door pulleys are installed on each traction point as a movable pulley; the steel wire rope is installed between the fixed pulley and the movable pulley, and the bridge winch 30 is used as a traction power. A soft lifting belt is set at the rear end of the traction point on the old inclined cable 27, and the lifting belt is lifted by a car crane; after the tower end is tensioned, the beam end is tensioned, and the old cable anchor cup nut 38 is pulled away from the anchor pad 40 by the bridge winch 30; the old cable anchor cup nut 38 at the beam end is removed, and the traction system of the bridge winch 30 at the beam end is loosened to make the beam end anchor cup exit the cable guide tube, and the loosening is continued until the winch traction system is free from force. If the anchor cup nut at the beam end cannot be removed, the old cable anchor cup 37 at the beam end can be cut off, the bridge deck winch 30 releases the bridge deck pull rope 31, and slowly releases the old cable anchor cup 37 out of the cable guide tube. During the whole process, a car crane is used to adjust the angle of the old cable anchor cup 37 and the tension rod 32 out of the cable guide tube; the car crane is continued to be used to hoist the cable body, the bridge deck winch 30 releases the bridge deck pull rope 31, and the old cable anchor cup 37 is relaxed toward the cable tower column 1 until it is completely free of force, and the release of the bridge deck winch 30 at the beam end is completed.

[0041] Step 3, dismantling the old inclined cable 27 at the tower end: use the tower top hanger 19 to hoist the first winch 21, the first lifting rope 22, and the first hook 23 to the top of the tower, and install the first row of steel pipe pair support auxiliary lifting inclined cable platform, the second row of steel pipe pair support auxiliary lifting inclined cable platform, the third row of steel pipe pair support auxiliary lifting inclined cable platform, the fourth row of steel pipe pair support auxiliary lifting inclined cable platform and the fifth row of steel pipe pair support auxiliary lifting inclined cable platform in the tower column 1 from bottom to top, and use the first winch 21, the first lifting rope 22, and the first hook 23 to hoist the second winch 24, the second lifting rope 25, and the second hook 26 onto each row of steel pipe pair support auxiliary lifting inclined cable platform.

[0042] When the old cable-stayed cable 27 removed from the tower end is lowered to the fifth row of steel pipe support auxiliary cable-stayed cable platform by using the first winch 21, the first lifting rope 22 and the first lifting hook 23, the second winch 24, the second lifting rope 25 and the second lifting hook 26 on the fifth row of steel pipe support auxiliary cable-stayed cable platform are used to lift the old cable-stayed cable 27.

[0043] When the old stay cable 27 is hoisted to the fourth row of steel pipes supporting the auxiliary platform for hoisting the stay cables, the second winch 24, the second hoisting rope 25 and the second hook 26 on the fourth row of steel pipes supporting the auxiliary platform for hoisting the stay cables are replaced to hoist the old stay cable 27.

[0044] When the old stay cable 27 is hoisted to the platform for assisting the hoisting of the stay cable by the third row of steel pipes, the second winch 24 , the second hoisting rope 25 , and the second hook 26 on the platform for assisting the hoisting of the stay cable are replaced to hoist the old stay cable 27 .

[0045] When the old stay cable 27 is hoisted to the second row of steel pipes supporting the auxiliary platform for hoisting the stay cable, the second winch 24, the second hoisting rope 25 and the second hook 26 on the second row of steel pipes supporting the auxiliary platform for hoisting the stay cable are replaced to hoist the old stay cable 27.

[0046] When the old stay cable 27 is hoisted to the first row of steel pipes supporting the auxiliary platform for hoisting the stay cable, the second winch 24, the second hoisting rope 25 and the second hook 26 on the first row of steel pipes supporting the auxiliary platform for hoisting the stay cable are replaced to hoist the old stay cable 27.

[0047] The old cable-stayed cable 27 on the bridge deck 2 is quickly moved by pulling the cable-unwinding trolley 28 through the bridge deck winch 30 and the bridge deck pull rope 31 .

[0048] Step 4, installation of new cable-stayed cables 29: including hanging of new cable-stayed cables 29 at tower end, laying of new cable-stayed cables 29 on beam surface, traction of new cable-stayed cables 29 at beam end, soft traction of steel strands at tower end of new cable-stayed cables 29, hard traction and tensioning of new cable-stayed cables 29 at tower end. The order of hoisting of new cable-stayed cables 29 at tower end is opposite to that of old cable-stayed cables 27.

[0049] Embodiment 2

[0050] As another embodiment, this embodiment 2 proposes, based on the embodiment 1, a more specific construction method of a high-efficiency cable replacement system for a multi-tower cable-stayed bridge:

[0051] The first stage of tensioning the tower end of the old inclined cable 27 is characterized by comprising: installing tensioning and tensioning equipment in the order of the connecting sleeve 36, the tensioning rod 32, the tensioning support foot 35, the jack 34, and the tensioning rod nut 33, rotating the tensioning rod nut 33 away from the jack cylinder 39 for a certain distance, the jack 34 supplies oil, the jack cylinder 39 extends 130 mm to subject the tensioning rod nut 33 to force, and after the old cable anchor cup nut 38 is detached from the anchor plate 40, the old cable anchor cup nut 38 is rotated away from the anchor plate 40 for a certain distance, and the two sets of tensioning equipment in the tower return oil in a graded and symmetrical manner as required until the old cable anchor cup nut 38 is pressed onto the anchor plate 40, and the above steps are repeated for tensioning until the old cable anchor cup nut 38 is rotated to the flat cap, and the first stage of tensioning is completed.

[0052] The second stage of the tower end tensioning of the old inclined cable 27 is characterized in that it includes: after the first stage of the tower end tensioning of the old inclined cable 27 is completed, if the tensioning force of the beam end is still greater than 30t, the second stage of the tower end tensioning of the old inclined cable 27 begins at this time, the second stage of the tower end tensioning of the old inclined cable 27 adopts a single-side tensioning method, the first stage of the tower end tensioning system of the old inclined cable 27 is dismantled, the auxiliary tension rod nut 42 and the auxiliary tension rod 41 are installed, the tensioning system is reassembled, and the auxiliary tension rod nut 42 is rotated away from the jack cylinder 39 by a certain distance, The jack 34 supplies oil, and the oil cylinder extends a certain distance to make the auxiliary tension rod nut 42 subject to force, and the old cable anchor cup nut 38 is rotated away from the old cable anchor cup 37. The jack 34 returns oil, so that the tension rod auxiliary nut 43 acts on the old cable anchor cup nut 38. When the tension rod auxiliary nut 43 cannot act on the anchor pad 40 due to the length of the connecting sleeve 36, a pad 44 is set between the old cable anchor cup nut 38 and the tension rod auxiliary nut 43, and the above steps are repeated to release the tension until the tension rod auxiliary nut 43 is rotated to the flat cap state, and the second stage of tensioning is completed.

[0053] The third stage of tensioning the tower end of the old inclined cable 27 is characterized in that it includes: after the jack cylinder 39 is extended a certain distance, the first tool anchor and the pressure plate 47 are installed, the jack 34 continues to supply oil, the first tool anchor and the pressure plate 47 are subjected to force to make the tension rod sub-nut 43 separate from the old cable anchor cup nut 38, and at the same time the force on the steel strand 45 is evenly adjusted, the tension rod sub-nut 43 is removed, the jack 34 returns oil, so that the second tool anchor and the pressure plate 48 act on the tension rod sub-nut 43, when the jack cylinder 39 has a remaining stroke of 20mm, the second tool anchor and the pressure plate 48 are installed, the oil is continued to be returned to make the second tool anchor and the pressure plate 48 subjected to force, the first tool anchor and the pressure plate 47 are removed, and the above steps are repeated until the old cable anchor cup 37 at the tower end is lowered a certain distance and the tensioning force at the beam end is less than 30t.

[0054] It should be noted that the parts in this embodiment that are the same or similar to those in the first embodiment can be referenced to each other and will not be described in detail in this application.

[0055] Embodiment 3

[0056] As another embodiment, this embodiment three is proposed on the basis of embodiments one and two. This efficient cable replacement system for a multi-tower cable-stayed bridge involves a technology for phased tensioning of the tower ends of the old cable-stayed cables 27 and a technology for assisting the lifting of the cable-stayed cables by using steel pipe braces between tower columns. The technology includes: a tower top hanger 19, tensioning equipment inside the tower, a first winch 21, tensioning equipment and a platform for assisting the lifting of the cable-stayed cables by using steel pipe braces.

[0057] The tensioning equipment inside the tower and the first winch 21 are installed on the top of the tower. The tensioning equipment inside the tower is used to tension the old cable-stayed cables 27 at the tower end. Several rows of steel pipe braces are installed at different heights between the tower columns to assist in lifting the cable-stayed cables. Each row of steel pipe braces is equipped with a second winch 24 on the cable-stayed cables. The first winch 21 and the second winch 24 on the several rows of steel pipe braces are used to relay the lifting of the old cable-stayed cables 27 and the new cable-stayed cables 29 removed from the tower end.

[0058] The described technology for releasing the old inclined cable 27 at the tower end in stages, a tower top hanger 19 and a first winch 21 are installed on the tower top, after the first winch 21 is positioned and fixed, the tensioning equipment is hoisted into the tensioning position in the tower by the first winch 21, the first hoisting rope 22, and the first hook 23, the tower top hanger 19 is used as a fixed point, the tower end construction hanging basket 50 is installed, and then the built-in shock absorber 46 of the tower end cable guide is removed, and the old cable anchor cup 37 and the old cable anchor cup nut 38 are cleaned of rust, the connecting sleeve 36 is adapted to the inner thread of the old cable anchor cup 37 to ensure that the connecting sleeve 36 can be connected to the old cable anchor cup 37. The release of the old inclined cable 27 at the tower end is divided into the first stage of releasing the old inclined cable 27 at the tower end, the second stage of releasing the old inclined cable 27 at the tower end, and the third stage of releasing the old inclined cable 27 at the tower end.

[0059] The tensioning equipment in the tower includes: a tensioning rod 32, a tensioning rod nut 33, a jack 34, a tensioning support leg 35, a connecting sleeve 36, a jack cylinder 39, an auxiliary tensioning rod 41, an auxiliary tensioning rod nut 42, a tensioning rod auxiliary nut 43, a pad 44, a first tool anchor and a pressure plate 47, a second tool anchor and a pressure plate 48, a soft traction connector 49, and a tower end construction hanging basket 50.

[0060] It should be noted that the parts in this embodiment that are the same or similar to those in Embodiments 1 and 2 can be referenced to each other and will not be described in detail in this application.

[0061] Embodiment 4

[0062] As another embodiment, this fourth embodiment proposes, on the basis of the third embodiment, a more specific efficient cable replacement system for a multi-tower cable-stayed bridge:

[0063] The technology of using steel pipes to support and assist in lifting and placing inclined cables between tower columns is as follows: a lightning rod 20 and a tower top hanger 19 are installed on the top of the tower column 1; a first winch 21, a first hoisting rope 22 and a first hook 23 are hoisted to the top of the tower by using the tower top hanger 19; a first row of steel pipes to support and assist in lifting and placing inclined cables, a second row of steel pipes to support and assist in lifting and placing inclined cables, a third row of steel pipes to support and assist in lifting and placing inclined cables, a fourth row of steel pipes to support and assist in lifting and placing inclined cables and a fifth row of steel pipes to support and assist in lifting and placing inclined cables are installed in sequence from bottom to top between tower columns 1.

[0064] The first row of steel pipes are supported to assist in the lifting of the cable-stayed platform. The first pair of supporting steel pipes 3 are fixed on both sides of the tower column 1 by using the embedded parts 4 for installing the supporting steel pipes. The first auxiliary lifting construction platform 5 is laid on the first pair of supporting steel pipes 3, and the first guardrails 6 are installed on both sides of the first auxiliary lifting construction platform 5.

[0065] The second row of steel pipes are supported to assist in the lifting of the cable-stayed platform. The second pair of supporting steel pipes 7 are fixed to both sides of the tower column 1 by using the embedded parts 4 for installing the supporting steel pipes. A second auxiliary lifting construction platform 8 is laid on the second pair of supporting steel pipes 7. Second guardrails 9 are installed on both sides of the second auxiliary lifting construction platform 8.

[0066] The third row of steel pipes is used to assist in the lifting of the cable-stayed platform. The third pair of steel pipes 10 are fixed on both sides of the tower column 1 by using the embedded parts 4 for installing the supporting steel pipes. A third auxiliary lifting construction platform 11 is laid on the third pair of steel pipes 10. A third guardrail 12 is installed on both sides of the third auxiliary lifting construction platform 11.

[0067] The fourth row of steel pipes is used to assist in the lifting of the cable-stayed platform. The fourth pair of supporting steel pipes 13 are fixed on both sides of the tower column 1 by using the embedded parts 4 for installing the supporting steel pipes. A fourth auxiliary lifting construction platform 14 is laid on the fourth pair of supporting steel pipes 13. Fourth guardrails 15 are installed on both sides of the fourth auxiliary lifting construction platform 14.

[0068] The fifth row of steel pipes is used to assist in the lifting of the cable-stayed platform. The fifth pair of steel pipes 16 are fixed on both sides of the tower column 1 by using the embedded parts 4 for installing the pair of steel pipes. A fifth auxiliary lifting construction platform 17 is laid on the fifth pair of steel pipes 16. Fifth guardrails 18 are installed on both sides of the fifth auxiliary lifting construction platform 17.

[0069] It should be noted that the parts in this embodiment that are the same or similar to those in Embodiments 1 to 3 can be referenced to each other and will not be described in detail in this application.

[0070] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

Claims

1. A construction method for an efficient cable replacement system for a multi-tower cable-stayed bridge, characterized in that: The following steps are involved: Step 1: Then remove the built-in shock absorber of the tower end cable guide, connect the connecting sleeve and the old cable anchor cup, and tension the old cable tower end in three stages; Step 2: Set a traction point on the beam surface corresponding to the beam end of the old cable, and lift the lifting belt; start to release the beam end, and use the bridge deck winch to pull the old cable anchor cup nut away from the anchor pad; loosen the old cable anchor cup toward the tower column until it is completely free of stress; Step 3: Use the tower top hanger to hoist the first winch to the tower top, install several rows of steel pipe supports from bottom to top between the tower columns to assist in hoisting the cable-stayed platform, and use the first winch and steel pipe supports at different heights to assist in hoisting the second winch on the cable-stayed platform to hoist the old cable removed from the tower end; Step 4: Install new stay cables.

2. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 1 is characterized in that: Use the tower top hanger to hoist the tensioning equipment and the first winch in the tower to the top of the tower. The tensioning equipment in the tower includes: tensioning rod, tensioning rod nut, jack, tensioning support foot, connecting sleeve, jack cylinder, auxiliary tensioning rod, auxiliary tensioning rod nut, tensioning rod auxiliary nut, pad, first tool anchor and pressure plate, second tool anchor and pressure plate, soft traction connector and tower end construction basket; after positioning and fixing the first winch, use the first winch, the first lifting rope and the first hook to hoist the tensioning equipment into the tensioning position in the tower, use the tower top hanger as a fixed point, install the tower end construction basket, then remove the built-in shock absorber of the tower end cable guide tube, clean the rust on the old cable anchor cup and the old cable anchor cup nut, and adapt the connecting sleeve and the thread inside the old cable anchor cup.

3. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 2 is characterized in that: In step one, in the first stage of tensioning the tower end of the old cable, the tensioning and tensioning equipment is installed in the order of the connecting sleeve, tension rod, tension support foot, jack and tension rod nut, the tension rod nut is screwed away from the jack cylinder for a certain distance, the jack supplies oil to make the tension rod nut stressed, and after the old cable anchor cup nut is detached from the anchor plate, the old cable anchor cup nut is screwed away from the anchor plate for a certain distance. The two sets of tensioning equipment in the tower return oil in a graded and symmetrical manner as required until the old cable anchor cup nut is pressed onto the anchor plate, and the above steps are repeated for tensioning until the old cable anchor cup nut is screwed to the flat cap, and the first stage of tensioning is completed.

4. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 3 is characterized in that: In step one, in the second stage of tensioning the tower end of the old inclined cable, a single-sided tensioning method is adopted. The tensioning system of the first stage of tensioning the tower end of the old inclined cable is dismantled, the auxiliary tension rod nut and the auxiliary tension rod are installed, and the tensioning system is reassembled. The auxiliary tension rod nut is screwed away from the jack cylinder for a certain distance, the jack supplies oil, and the cylinder extends a certain distance to make the auxiliary tension rod nut stressed, and the old cable anchor cup nut is screwed away from the old cable anchor cup, and the jack returns oil, so that the tension rod auxiliary nut acts on the old cable anchor cup nut. When the tension rod auxiliary nut cannot act on the anchor plate due to the length of the connecting sleeve, a pad is set between the old cable anchor cup nut and the tension rod auxiliary nut, and the above steps are repeated for tensioning until the tension rod auxiliary nut is screwed to the flat cap state, and the second stage of tensioning is completed.

5. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 4 is characterized in that: In step one, in the third stage of tensioning the old cable tower end, the first tool anchor and pressure plate are installed after the jack cylinder is extended a certain distance, and the jack continues to supply oil. The first tool anchor and pressure plate are stressed to make the tension rod sub-nut separate from the old cable anchor cup nut. At the same time, the force on the steel strand is evenly adjusted, the tension rod sub-nut is removed, and the jack returns oil to make the second tool anchor and pressure plate act on the tension rod sub-nut. When the remaining stroke of the jack cylinder is less than or equal to 20mm, the second tool anchor and pressure plate are installed, and the oil is continued to be returned to make the second tool anchor and pressure plate stressed, and the first tool anchor and pressure plate are removed. The above steps are repeated until the old cable anchor cup at the tower end is lowered a certain distance and the tension force at the beam end is less than 30t.

6. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 1 is characterized in that: In step 2, a traction point is set on the beam surface near the beam end of the old inclined cable, and a set of three-door pulleys are fixed with a U-shaped clamp as a fixed pulley; traction points are set on the old inclined cable at different positions away from the cable guide tube with a soft lifting belt, and a set of single-door pulleys are installed on each traction point as a movable pulley; the steel wire rope is installed between the fixed pulley and the movable pulley, and the bridge deck winch is used as the traction power. A soft lifting belt is set at the rear end of the traction point on the old inclined cable, and the lifting belt is lifted by the car crane; the beam end is started to be released, and the bridge is passed through the bridge The deck winch pulls the old cable anchor cup nut away from the anchor pad; remove the old cable anchor cup nut at the beam end, loosen the bridge deck winch traction system at the beam end, make the anchor cup at the beam end exit the cable guide tube, and continue to loosen it until the winch traction system is no longer stressed; the bridge deck winch releases the bridge deck pull rope to release the old cable anchor cup out of the cable guide tube. During the whole process, a truck crane is used to adjust the angle of the old cable anchor cup and the tensioning rod out of the cable guide tube; continue to use the truck crane to lift the cable body, and the bridge deck winch releases the bridge deck pull rope to loosen the old cable anchor cup toward the cable tower column until it is completely free of stress, and the tensioning of the bridge deck winch at the beam end is completed.

7. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 1 is characterized in that: In step three, the first winch, the first lifting rope and the first hook are hoisted to the top of the tower by the tower top hanger, and five rows of steel pipe support auxiliary cable-stayed cable platforms are installed from bottom to top between the tower columns. The second winch, the first lifting rope and the first hook are respectively hoisted to each row of steel pipe support auxiliary cable-stayed cable platforms by the first winch, the first lifting rope and the first hook. When the old cable-stayed cable removed from the tower end is hoisted downward to the corresponding steel pipe support auxiliary cable-stayed cable platform by the first winch, the first lifting rope and the first hook, the old cable-stayed cable is replaced by the second winch, the second lifting rope and the second hook on the corresponding steel pipe support auxiliary cable-stayed cable platform to lift the old cable. The old cable-stayed cable on the bridge deck is moved by pulling the cable-unfolding trolley with the bridge deck winch and the bridge deck pull rope.

8. The construction method of the efficient cable replacement system for a multi-tower cable-stayed bridge according to claim 7 is characterized in that: Step four includes hanging the new cable tower end, laying out the new cable beam surface, pulling the new cable beam end, soft pulling of the steel strands at the new cable tower end, hard pulling and tensioning of the new cable tower end. The order of hoisting the tower end of the new cable is opposite to that of the old cable.

9. An efficient cable replacement system for a multi-tower cable-stayed bridge, characterized in that: Obtained by the method according to any one of claims 1 to 8.

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