Erecting method for synchronous traction and horizontal saddle entering of rotary main cable of single-tower suspension bridge

Abstract

The invention relates to an erection method for synchronous traction and horizontal saddle entering of a single-tower suspension bridge rotary main cable, and belongs to the field of bridge main cable erection construction. The head end and the tail end of the cable strand are synchronously pulled to the opposite shore anchorage from the rotary anchorage, the main cable strand erection is divided into reference cable strand erection and general cable strand erection, the reference cable strand erection is carried out firstly, then the general cable strand erection is carried out according to the serial number sequence, and the main cable strand erection is completed. The erection of the single cable strand relates to cable strand traction, cable strand transverse movement, cable strand saddle entering, cable strand sag adjustment and anchor span tension adjustment. The main cable strand is folded and unfolded to the inner side of the annular channel and then is separated and dragged after reaching the inner side of the annular channel, the saddle entering action of the cable strand in the annular channel and the saddle entering action of a quay crane tower are synchronously carried out at the same time, and the erecting efficiency of the main cable strand is improved.

Description

Technical Field

[0002] The invention relates to a bridge construction method, and in particular to a method for erecting a rotary main cable of a single-tower suspension bridge. Background Art

[0004] A revolving cable is a main cable arrangement in which the main cable starts from an anchor on one bank, goes around the anchor on the opposite bank, and then returns to the anchor on the starting bank. The main cable is arranged in a U shape on the horizontal projection plane, and the main cable strands pass continuously at the revolving anchor on the opposite bank. A revolving saddle system consisting of a revolving main saddle and two revolving cable saddles is used to realize the 180° revolving of the cable strands on the opposite bank, replacing the traditional disconnected dispersed anchoring method, making full use of the constant load self-balancing characteristics of the main cable, and optimizing the anchoring structure and anchoring structure.

[0005] According to the characteristics of the revolving cable, the cable strand preforming technology disclosed in the patent publication number CN 117139508 A is used in the production of the cable strand. The cable strand is preformed according to the bending arc of the cable saddle at the three turning saddles, and the cable body cross-section of the cable strand at the revolving main saddle and the turning saddle is pre-shaped from a hexagon to a quadrilateral using tooling. The problem of uneven force on the main cable strand due to the length difference between the inner steel wire and the outer steel wire when the main cable strand of the revolving cable passes through the 180° horizontal revolving bend at the three turning saddles is solved, and the shortcomings of manually shaping the cable strand on site when the cable strand enters the saddle are avoided, and the cable strand entering the saddle is difficult to ensure, and it is time-consuming and labor-intensive.

[0006] The revolving cable combines the two upstream and downstream main cables of the traditional suspension bridge into one. The cable strand is long and needs to be turned, which makes it difficult to install. The traditional method of pulling a single main cable strand has problems such as long pulling path, low efficiency, and twisting and deformation of the cable strand when turning. In response to these problems, the main cable strand is folded in half and the cable is pulled and released from the opposite bank to both sides of the tower bank simultaneously, which shortens the cable release path and improves the efficiency of cable installation. At the same time, to cooperate with this installation plan, the main cable strand adopts the cable strand folding and coiling method disclosed in patent publication number CN 117142248 A. The two anchor heads of the coiled cable strand are both on the outside, and the folded part is fixed with a fixed bracket and placed on a specific cable release disk. When releasing the cable, the cables at both ends are released simultaneously from the revolving cable saddle and pulled from both sides to the bridge tower on the opposite bank.

[0007] In the actual construction process, the folded and coiled cable strands have high requirements for the synchronization of the traction systems on both sides. If the traction speed deviation is large, the cable strands are prone to cross interference, causing damage to the main cable and affecting the construction efficiency. In order to facilitate the installation of the slewing cable, a sunken annular anchor chamber (annular channel) is set on the slewing anchor. The slewing main saddle and the slewing cable saddle are set in the annular anchor chamber. The slewing cable is laid and pulled on the horizontal surface of the slewing anchor and follows the traction channel. After the traction is completed, the main cable is moved horizontally from the traction channel to the annular anchor chamber to enter the saddle. That is, the distance of the main cable when it is pulled and the distance of the final main cable anchoring are different at the slewing anchor, and there is a length difference. In the prior art, the traction channel is usually arranged on the outside of the annular anchor chamber, and the traction length of the cable body along the traction channel is longer than the anchoring length in the annular anchor chamber. Since the length of the main cable is prefabricated according to its anchoring length in the annular anchor chamber, this results in that when the main cable is fully tractioned and deployed, the two anchor heads of the main cable have not yet reached the anchoring position on the opposite bank. At this time, the main cable needs to complete the lateral movement from the traction channel to the annular anchor chamber before continuing to be pulled. There are problems of cross-interference and low efficiency in the lateral movement and subsequent traction coordination operations. Moreover, the cable strands move greatly during the lateral movement, which makes it difficult to control and protect the cable strand linearity. If the traditional manual hammering is used to shape the cable strands into the saddles at the three saddle positions in the annular anchor chamber, the wooden wedging process will make it difficult to maintain the shape of the cable strands, resulting in wire drumming. The traditional main cable strand linearity control adopts the "sag adjustment method", but the three saddles are only a few meters apart and are located in the annular anchor chamber. Obviously, the main cable strands of the turnaround section cannot be controlled linearly by the "sag adjustment method". Based on the existing main cable strand installation method, the linear control of the main cable in the turnaround section becomes a major problem.

[0008] In summary, the above issues need to be further studied to form a more reliable construction process for rotary cables. Summary of the invention

[0010] The technical problem to be solved by the present invention is to provide a method for synchronously pulling and horizontally placing the main cable of a single-tower suspension bridge into the saddle according to the above-mentioned prior art. The main cable installation process is as follows:

[0011] Setup and commissioning of cable strand synchronous traction system → hoist cable strand reel onto cable laying mechanism → pull out cable strand front anchor and connect it to puller → pull cable strand anchors at both ends to opposite bank anchor → check and correct cable strand breakage and twisting → remove cable strand front anchor from puller → temporarily anchor cable strand anchors at opposite bank anchor → lateral movement of cable strand on slewing anchor side → saddle cable strand in annular channel → cable strand linearity verification → cable strand anchor span tension adjustment

[0012] The main features of the erection method:

[0013] 1. The folded main cable strands are still used to release the cable to the opposite bank at the slewing anchor side. A synchronous control system is used in the main cable traction system to achieve synchronous traction of the upstream and downstream cable strands to the opposite bank, ensuring the quality of the cable strands and improving the traction efficiency.

[0014] 2. Fold the main cable strands in half and unfold them to the inside of the annular channel, then separate and pull them inside the annular channel. The saddle-entry action (lateral movement) of the cable strands in the annular channel is carried out simultaneously with the saddle-entry action of the opposite shore bridge tower, which improves the efficiency of the main cable strand installation.

[0015] 3. Multiple gantries are set up along the inner side of the annular channel, and cable strand transverse sliding rails are installed on both sides of each gantries. The electric hoist installed on the sliding rails is used to pull the cable strands horizontally in the opposite direction to achieve the overall transverse movement of the cable strands in the slewing saddle section. On the slewing anchor side, the cable strands are moved backward and transversely as a whole into the annular channel.

[0016] 4. The revolving cable saddle includes a revolving main saddle and two rotating cable saddles, which are all arranged in an annular channel. A horizontal pushing device is arranged in the annular channel. The horizontal pushing device is horizontally opposite to the revolving cable saddle. After the cable strand is horizontally moved down into the annular channel, the horizontal pushing device pushes the cable strand horizontally into the saddle groove of the revolving cable saddle, which can effectively control the quality of the cable strand entering the saddle.

[0017] 5. Construction method of installation by marking method: When making cables, corresponding marking points are set at the characteristic positions of the cables. When installing the main cables, the marking points on the saddles are installed according to these marking points. This can realize the linear control of the saddle section, reduce the influence of installation environmental factors, reduce repeated cable adjustment work on site, and improve the accuracy and efficiency of cable installation.

[0018] The technical solution of the present invention is: a method for synchronously pulling and horizontally placing the main cable of a single-tower suspension bridge into a saddle, wherein the head and tail ends of the cable strand are synchronously pulled from the swivel anchor to the opposite bank anchor, and the main cable strand erection is divided into reference cable strand erection and general cable strand erection, and the reference cable strand is erected first, and then the general cable strand is erected in the order of numbering, and the erection of a single cable strand involves cable strand pulling, cable strand lateral movement, cable strand placing into a saddle, cable strand sag adjustment and anchor span tension adjustment, and the specific process includes:

[0019] 1. Construction preparation: Before the cable strands are formally erected, the cable saddles are installed in place, the catwalks are erected, and the cable strand traction system is set up and debugged.

[0020] 2. Cable traction: A single-line reciprocating traction system is used for erection, with one traction system arranged upstream and downstream. The cable-releasing area is set on the rotating anchor side, and the winch of the traction system is set behind the anchor on the opposite bank. The two ends of the cable are simultaneously pulled to the side of the cable saddle on the opposite bank through the traction system, and the connection between the anchor heads at both ends of the cable and the traction system is released. The anchor heads at both ends are temporarily anchored, and the rotating sections of the cable are all pulled to the inside of the annular channel.

[0021] 3. Transverse movement of cable strands: The cable strands that have been pulled are still supported on the drum. At this time, the cable strands are offset relative to the annular channel and cannot enter the saddle directly. The cable strands are lifted up and pulled back from the inside of the annular channel to the annular channel. Since the cable strands are pulled inside the annular channel before the transverse movement, the transverse movement of the cable strands can achieve the synchronous transverse movement and saddle entry operation of the annular channel and the tower top cable saddle.

[0022] 4. Cable strands saddled: The order of cable strands saddled: saddled the rotating main saddle and the tower top main saddle at the same time → saddled the rotating side saddle → saddled the loose cable saddle. When saddled, align the marked points on the cable strands with the marked points on the saddle. Specific saddled methods:

[0023] The main saddle is inserted horizontally from the middle of the saddle to both sides. When the cable strand is moved horizontally to the top of the annular channel, it is lowered into the annular channel. The lowering height is consistent with the height of the corresponding cable groove. The cable strand is pushed into the cable groove by horizontal pushing. The marking point of the cable strand is adjusted to align with the center point of the saddle and then wedged tightly with wooden wedges.

[0024] The main saddle of the tower top is inserted from the side span to the middle span. When inserting the saddle, control the cable strands to prevent twisting, and gently lower the cable strands to the specified position in the cable saddle cable groove. After the marked point on the cable strands is aligned with the mark on the saddle, tighten it with a wooden wedge.

[0025] The direction of entering the saddle on both the upstream and downstream sides is from the side span to the middle span. When entering the saddle, use the horizontal fall chain to adjust the cable strand into the saddle groove, and after the marked point on the cable strand is aligned with the center point of the saddle, use a wooden wedge to wedge it tightly.

[0026] The direction of insertion of the loose cable saddle is from the anchor span side to the side span side. When inserting the loose cable saddle, align the marking point on the cable strand with the mark on the saddle, and then tighten it with a wooden wedge.

[0027] 5. Cable strand linear measurement and verification: After the cable strands are installed, linear measurement is carried out. If the measurement results meet the main cable verticality requirements, no adjustment is required. If not, vertical adjustment is required.

[0028] 6. Anchor span cable tension adjustment: Adjust the tension from both anchor head ends to make the anchor span cable tension meet the design requirements.

[0029] As one of the preferred embodiments, step one, the saddle includes a revolving main saddle, two rotating cable saddles, a tower top main saddle and a loose cable saddle. The revolving main saddle and the revolving cable saddle are arranged in the annular channel of the revolving anchor. The two revolving cable saddles are symmetrically located upstream and downstream of the revolving main saddle. The tower top main saddle is a pair and is arranged on the top of the bridge tower on the opposite bank. The loose cable saddle is arranged between the bridge tower and the anchor on the opposite bank.

[0030] As one of the preferred implementations, in step 2, the cable strand traction system is mainly composed of a winch, a traction rope and a puller connected in series, the two ends of the traction rope are respectively wound into the main and auxiliary winches, one end is used for winding up for traction, and the other end is used for unwinding, the main and auxiliary winches are linked to make the traction rope reciprocate; the two ends of the cable strand are respectively pulled by the upstream traction system and the downstream traction system, and the winches of the upstream and downstream traction systems are synchronously controlled by a synchronous controller to ensure synchronous traction of the upstream and downstream ends of the cable strand; after the catwalk is erected, the gantry guide wheel group is installed and the traction rope is supported on the guide wheel group to form a cable strand traction system, and the cable strand drum is installed on the catwalk, the tower top and the opposite bank anchor to realize the cable strand traction erection.

[0031] As one of the preferred implementations, step 2, the step of synchronously pulling the upstream and downstream strands:

[0032] Step 2.1, the main cable strand is coiled in half, and the main cable strand pay-off drum is a double-drag pay-off drum, which is used to support the main part of the cable strand coil and the folded ring part of the cable strand respectively;

[0033] Step 2.2, arrange the cable tray behind the rotary anchor annular channel, the rotary main saddle and the rotating cable saddle are located inside the annular channel and are arranged on the inner wall of the annular channel, and the cable tray is installed on the cable tray frame by using on-site lifting equipment;

[0034] Step 2.3, on the working surface of the slewing anchor, rollers are arranged along the inner side of the front of the annular channel. The arrangement of the rollers is consistent with the traction direction, so as to ensure that the two cables are released in the predetermined direction;

[0035] Step 2.4, drag out the two anchor heads outside the cable drum, lift the two anchor heads at the same time with the lifting equipment and pull them forward, and connect the two anchor heads to the pullers of the upstream and downstream traction systems respectively;

[0036] Step 2.5, start the winch of the traction system to traction the cable strands, separate the two anchor heads when they reach the position of the main saddle of the circular channel, and traction them along the front side of the circular channel to the upstream and downstream saddles, pass through the tower top and the loose cable saddle on the opposite bank, and finally anchor on the opposite bank;

[0037] Step 2.6, when the anchor head reaches the predetermined position, release the connection between the anchor head and the puller, and temporarily anchor the anchor head on the opposite bank.

[0038] During the traction process, pay attention to the remaining amount of the cable strand in the cable drum. When the folded section of the cable strand is completely out of the cable drum, lift the folded section of the cable strand and pull it back from the midpoint of the cable strand, i.e. the folding point, to ensure smooth traction until all the cables are pulled to the inner side of the annular channel.

[0039] The pulling speed of the cable strand is controlled at 15-25m / min. At the turning and bending position, the speed is appropriately reduced to 5m / min.

[0040] As one of the preferred implementations, in step three, the specific method of lateral movement of the cable strands includes:

[0041] (3.1) Lateral movement of the cable strands at the slewing main saddle: First, use the winch on the gantry at the entrance of the catwalk on the slewing anchor side to pull the cable strands back to the slewing main saddle side, loosen the cable strands in the slewing section, and then perform the overall lateral movement;

[0042] (3.2) Horizontal movement of the cable strand at the saddle: a gantry is set at the saddle position, an electric hoist is set on the gantry, and electric hoist slide rails are set on the longitudinal beams on both sides of the gantry. The cable strand is lifted by the electric hoist and then moves along the slide rail to achieve horizontal movement of the cable strand;

[0043] (3.3) At a distance of 20 m on each side of the main saddle at the top of the tower, 20 m from the rear side of the loose cable saddle, and 2 m on each side of the rotating cable saddle, the cable strands are subjected to lateral displacement and reverse pulling.

[0044] As one of the preferred embodiments, in step four, the rotating main saddle adopts a horizontal pushing device to horizontally enter the cable strand into the saddle, and a horizontal pushing device is arranged on the inner wall of the annular channel opposite to the rotating main saddle. The horizontal pushing device includes a vertical slide rail, a slider, a pull rope, an electric push rod and a support ring. The vertical slide rail is fixed on the inner wall of the annular channel, the slider is connected to the electric push rod, and the electric push rod moves up and down along the vertical slide rail through the slider. One end of the pull rope is fixed, and the other end is connected to the electric push rod. The support ring is arranged at the front end of the electric push rod, and the electric push rod is horizontally arranged to realize the pushing action in the horizontal direction.

[0045] As one of the preferred implementations, step five, the sag adjustment is performed at night when the temperature is stable, there is no rain or fog, and the wind speed is less than level 5. The basic conditions for temperature stability are: the temperature difference of the cable strand in the length direction is ≤2°C, and the temperature difference of the cable strand in the cross section is ≤1°C.

[0046] The order of adjusting the verticality of the cable strands is the middle span first, then the side span and finally the anchor span. The middle and side spans use the hand winch installed on the gantry in conjunction with the pulley block to retract and release the cable strands at the saddle position to achieve the purpose of verticality adjustment; the anchor span uses the jack to adjust the tension of the cable strands.

[0047] The method for adjusting the sag of the main cable strand is: first accurately align the mark point of the strand at the midpoint of the arc of the main saddle of the revolving cable strand with the apex of the arc of the rotating cable saddle, and tighten and fix it with wooden wedges, then adjust the position of the strand at the midpoint of the arc of the rotating cable saddle on both sides, and then adjust the position of the strand at the apex of the main tower saddle until the sag of the middle span meets the requirements and then fix it, then adjust the sag of the side span strand, and fix it at the loose cable saddle after the sag design requirements are met, and finally adjust the anchor span. The anchor span strand uses a through-type jack to adjust the strand tension to meet the design requirements. After the sag adjustment is completed, the strand should be marked at the saddle to check for slippage during the subsequent cable strand erection. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is the number of the main cable strands in the slewing main saddle in the embodiment of the present invention;

[0050] Figure 2 is the number of the main cable strands in the saddle in the embodiment of the present invention;

[0051] Figure 3 A schematic diagram of an upstream and downstream traction system in an embodiment of the present invention;

[0052] Figure 4 A top view of a cable tray according to an embodiment of the present invention;

[0053] Figure 5 It is a schematic diagram of installing the cable drum onto the cable placing rack by the lifting equipment in the embodiment of the present invention;

[0054] Figure 6 This is a schematic diagram of the cable strand being pulled along the inner side of the annular channel in an embodiment of the present invention;

[0055] Figure 7 Schematic diagram of the transverse movement of the cable strand in the turning section in an embodiment of the present invention;

[0056] Figure 8 Schematic diagram of the lateral shift and reverse pulling of the cable strands in an embodiment of the present invention;

[0057] Fig. 9 It is a schematic diagram of the transverse movement of the rotary main saddle in an embodiment of the present invention (longitudinal diagram);

[0058] Fig.10 It is a schematic diagram (top view) of the lateral movement of the rotary main saddle in an embodiment of the present invention;

[0059] Fig.11 It is a schematic structural diagram of a horizontal pushing device in an embodiment of the present invention;

[0060] Fig.12 Schematic diagram of the position of the marking points of the main cable strands in an embodiment of the present invention;

[0061] Fig.13A simplified diagram for calculating the cable strand shape in an embodiment of the present invention;

[0062] In the figure, 1 is a cable tray, 2 is a cable strand, 3 is a puller, 4 is a traction rope, 5 is a main winch, 6 is an auxiliary winch, 7 is a drum, 8 is a circular channel, 9 is a rotating main saddle, 10 is a rotating cable saddle, 11 is an anchor head, 12 is a gantry, 13 is an electric hoist, 14 is a slide rail, 15 is a horizontal jacking device, 1501 is an electric jack, 1502 is a support ring, 1503 is a slider, 1504 is a vertical slide rail, and 1505 is a pull rope. DETAILED DESCRIPTION

[0064] The present invention is further described in detail below in conjunction with examples. The examples are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0065] This project adopts the revolving cable strand installation scheme of pulling both ends (head and tail) of the cable strand to the opposite bank at the revolving anchor. The cable strand installation includes cable strand pulling, cable strand lateral movement, cable strand saddle, cable strand sag adjustment and anchor span tension adjustment. The installation method of the main cable strand is as follows:

[0066] 1. Construction preparation

[0067] After the saddle is installed, the catwalk is erected, and all kinds of construction machinery and equipment are arranged in place, the traction system is set up and debugged.

[0068] 2. Main cable strand installation sequence and process

[0069] The order of erection of the main cable strands is from small to large according to the strand number.

[0070] The installation of main cable strands is divided into the installation of reference strands and the installation of general strands. The strand with the design number 1# is the reference strand, and the rest are general strands. The installation sequence of general strands is from 2# to 121#. Figure 1 , Figure 2 The cable installation process is as follows:

[0071] Setup and commissioning of cable strand synchronous traction system → hoist cable strand reel onto cable laying mechanism → pull out cable strand front anchor and connect it to puller → pull cable strand anchors at both ends to opposite bank anchor → check and correct cable strand breakage and twisting → remove cable strand front anchor from puller → temporarily anchor cable strand anchors at opposite bank anchor → move cable strand horizontally → put cable strand into saddle → check cable strand linearity → adjust cable strand anchor span tension.

[0072] 3. Main cable traction system setting and debugging

[0073] The main cable is erected using a single-line reciprocating traction system, with one traction system arranged upstream and downstream. The cable-releasing area is set on the revolving anchor, located outside the annular channel. The winch of the traction system is set behind the anchor on the opposite bank, and the anchor heads of the cable strands and tails are simultaneously pulled to the anchor on the opposite bank through the traction system. The traction system is mainly composed of the main and auxiliary winches, traction ropes and pullers connected in series. The two ends of the traction rope of the traction system are respectively wound into the main and auxiliary winches, one end is used for traction rope winding and traction, and the other end is used for rope release. The main and auxiliary winches are linked to make the traction rope reciprocate. A synchronous controller is used to synchronously control the winch to ensure synchronization of traction and cable release, and synchronization of the upstream and downstream traction systems.

[0074] The overall idea of ​​synchronous control of the traction system is to enable the winch synchronization mode, take one of the winches as the reference, let the other winches rotate synchronously with the reference winch, and adjust the rotation speed of other winches according to the detected difference in the amount of rope retracted and released, so as to achieve synchronous retracting and releasing of multiple winches and complete the synchronous traction of upstream and downstream rope strands.

[0075] The traction system is laid above the main cable, along the saddle, the top of the main tower and the opposite shore anchorage, so as to realize the traction and installation of the main cable strand from the saddle to the saddle. Figure 3 shown.

[0076] After the catwalk is erected, the gantry guide wheel group is installed and the traction rope is supported on the guide wheel group to form a rope strand traction system. The rope strand traction installation can be realized by installing rope strand rollers on the catwalk, tower top and opposite bank anchor.

[0077] 4. Synchronous traction of upstream and downstream cables

[0078] (4.1) The main cable strands are folded in half. To ensure the quality of the folded strands, a special double-towed tray is used for laying the cable. One tray is used to support the main body of the strand, and the other tray is used to support the folded ring part of the strand. Figure 4 shown.

[0079] (4.2) Place the cable tray behind the main cable saddle on the slewing cable saddle side, and use the on-site lifting equipment to install the cable tray on the cable tray rack. Figure 5 shown.

[0080] (4.3) Rollers are installed along the inner side of the annular channel and at the turning point. The rollers are used to support the cable strands to ensure that the cables on both the upstream and downstream sides are released in the predetermined direction. Figure 6 shown.

[0081] (4.4) Drag out the two anchor heads on the outer side of the cable drum, lift the anchor heads with the lifting equipment and pull them to the front end of the gantry at the main saddle, and connect the anchor heads with the puller of the traction system by manual cooperation with the lifting equipment.

[0082] (4.5) Start the main winch of the traction system to pull the rope strands, control the winches on both the upstream and downstream sides to keep them synchronized, and keep the retracting and releasing speeds consistent. The auxiliary winch always maintains a certain counter-pulling force.

[0083] (4.6) In the anchorage chamber in front of the loose cable saddle, when the front anchor head reaches the predetermined position, use a winch or tower crane to help release the connection between the front anchor head of the cable strand and the puller, slowly lower the front anchor head, and use the pull rod to temporarily anchor the cable strand anchor head to the anchoring system.

[0084] (4.7) During the cable pulling process, attention should be paid to the remaining cable in the cable drum. When the folded section of the cable is released from the cable drum, the section of the cable should be lifted by the on-site lifting equipment until the folded section of the cable is completely pulled to the inner side of the annular channel. At the same time, the cable should be pulled back from the folding point of the cable, i.e. the midpoint of the cable, to ensure smooth pulling.

[0085] (4.8) The pulling speed of the cable strands should be controlled at 15-25 m / min. At places with bending changes such as saddles, the operating speed should be appropriately reduced to 5 m / min to reduce the impact of the puller on the gantry.

[0086] 5. Lateral movement of the cable strand

[0087] (5.1) The cable strands after traction are still supported on the drum, offset by a certain distance from the center line of the cable strand entering the saddle. The electric hoist, slide rail and winch on the gantry at the main saddle and the rotating cable saddle are used to lift and move the cable strands horizontally to the saddle position. After traction is completed, all the cables in the rotating section are located on the inner side of the annular channel. In this case, the cables of the main saddle and the main saddle on the tower top can be moved horizontally into the saddle synchronously, which improves the working efficiency.

[0088] (5.2) If the cable strand at the slewing saddle moves horizontally, it is necessary to first use the winch on the gantry at the entrance of the slewing anchor catwalk to pull the cable strand back to the slewing saddle side, loosen the slewing section cable strand, and then move the entire cable strand horizontally.

[0089] (5.3) Slide rails are set on the longitudinal beams on both sides of the gantry at the revolving main saddle. The electric hoist cooperates with the slide rails. The cable strand is lifted by the electric hoist and then moves along the slide rails to achieve lateral movement of the cable strand.

[0090] (5.4) Install the cable gripper on the cable strand at a position 20m in front and behind the main saddle on the top of the tower, about 20m behind the loose cable saddle, and about 2m on both sides of the rotating cable saddle. Use the hoist rope to connect the cable gripper to the winches on the tower top gantry, loose cable saddle gantry, and rotating cable saddle gantry respectively, to form their respective lifting and transverse movement systems.

[0091] (5.5) After all the cable gripper lifting systems are installed, start all the lifting winches at the same time to lift the entire cable strand off the cable strand roller. After confirming that all the cables of the full span have left the roller, start the electric hoist on the revolving main saddle gantry to drag horizontally and move the cable strand backward to the saddle entry position of the annular channel.

[0092] 6. Saddle the buttocks

[0093] (6.1) The cable strands shall be put into the saddle in the following order: the main saddle and main tower cable saddle shall be put into the saddle synchronously → the saddle of the saddle of the saddle of the swivel side-turn cable → the saddle of the loose cable.

[0094] (6.2) The cable strands at the revolving main saddle are made using bending preforming and shaping technology. To ensure the quality of the cable strands when they are horizontally inserted into the saddle, a cable strand horizontal jacking device is used to insert the cable strands horizontally into the saddle to prevent the cable strands from bulging or loosening. The vertical track of the horizontal jacking device is installed on the inner wall of the annular channel corresponding to the revolving main saddle in advance, and the electric jack is installed on the vertical track. The vertical position of the horizontal jacking device is adjusted by moving up and down. The front end of the electric jack is used to install the support ring to act on the main cable strands, and the thrust of the electric jack is used to realize the horizontal insertion of the cable strands into the saddle.

[0095] (6.3) When the cable strand is inserted into the saddle, the marking point on the cable strand should be precisely aligned with the marking point on the saddle. The main saddle is inserted horizontally, from the middle of the saddle to both sides. When the cable strand is moved horizontally to the top of the annular channel, the cable strand is lowered to the height to be installed, the height of the horizontal jacking device of the cable strand is adjusted, the support ring on the head of the jack rod is pressed against the cable strand, and the electric jack rod is used to apply thrust to push the cable strand to the specified position in the cable bearing groove of the saddle. After the marking point on the cable strand is aligned with the center point of the saddle, it is wedged with a wooden wedge.

[0096] (6.4) Order of saddle insertion of the revolving cable saddle: After the saddle insertion of the cable strands of the revolving main saddle section is completed, the saddle insertion of the revolving cable saddles on both the upstream and downstream sides is carried out. The direction of the revolving cable saddle insertion is from the side span to the middle span. When saddle insertion, use the horizontal fall chain to adjust the cable strands into the saddle groove. Align the marked point on the cable strand with the center point of the saddle and wedge it tightly with a wooden wedge.

[0097] (6.5) Direction of saddle insertion for the main saddle at the top of the tower: The saddle at the top of the tower is inserted from the side span to the middle span. When inserting the saddle, strictly control the position of the red wire of the cable strand in the saddle to prevent the cable strand from twisting. The two hooks on the tower top gantry are lowered smoothly at the same time, and the cable strand is placed in the specified position in the cable saddle bearing groove. After the mark on the cable strand is aligned with the mark on the saddle, it is wedged tightly with a wooden wedge.

[0098] (6.6) Direction of loose cable saddle insertion: The loose cable saddle is inserted from the anchor span side to the side span side. When the loose cable saddle is inserted, align the marked point on the cable strand with the mark on the cable saddle and tighten it with a wooden wedge.

[0099] 7. Cable Strand Line Shape Control

[0100] In order to facilitate the installation of cables and the control of their linear shape, corresponding marking points are set on the cables during cable making, corresponding to the loose cable saddles, the middle of the side span, the main saddle on the tower top, the middle of the middle span, and the transfer cable saddle, and are marked with specific markers.

[0101] A total of 13 marking points are set on the main cable, including the arc vertex M1 of the loose cable saddle, the mid-span point M2 of the side span, the arc point M3 of the main saddle on the tower top, the mid-span M4 of the middle span, the arc vertex M5 of the turning cable saddle, the arc vertex M6 of the main turning cable saddle, and M0 near the two anchor heads.

[0102] According to the "Highway Engineering Quality Inspection and Assessment Standard" (JTG F80 / 1-2017), the allowable deviation of the cable strand elevation of the main cable of the suspension bridge is shown in the following table:

[0103] Main cable installation measurement project

[0104]

[0105] Note: L is the mid-span diameter, measured in mm when calculating the specified value or allowable deviation.

[0106] According to the mid-span diameter of the main cable side and the allowable positive and negative deviation values, the cable mid-span elevation deviation is calculated, and then the positive and negative deviation values ​​of the main cable strand length of this span are calculated, and then the deviation of the cable strand length is obtained. Finally, it is compared with the deviation of the cable strand length produced in the factory. If it meets the requirements, this marking method can be used to control the cable strand linear shape for alignment installation. Otherwise, the conventional linear shape measurement and adjustment method is used to control the cable strand linear shape.

[0107] Cable linear equation:

[0108] (1)

[0109] Where:

[0110] H is the horizontal tension of the cable strand;

[0111] q is the unit weight of the cable strand;

[0112]

[0113]

[0114] By adjusting the horizontal tension H of the cable strand, different line shapes can be obtained. When x=L / 2, iterative calculation is performed until the mid-span sag f is consistent with the design value under a specific horizontal force H.

[0115] (2)

[0116] Finally, the length of this cable is obtained:

[0117] (3)

[0118] Taking the side span cable line of a suspension bridge as an example, L=540m, c=108m, f=25.785m, q=22kg / m, the iterative calculation results in the horizontal tension H=31800kg, and the linear equation is:

[0119]

[0120] The integrated cable length is 553.779m.

[0121] The allowable deviation of the cable mid-span elevation is ±L / 10000, which is ±0.054m. Therefore, the maximum mid-span sag f is 25.839m and the minimum is 25.731m. The linear equation and cable length are calculated iteratively respectively.

[0122] When f=25.839m, H=31735kg, the linear equation is:

[0123]

[0124] The integral length of the cable is 553.792m.

[0125] When f=25.731m, H=31867kg, the linear equation is:

[0126]

[0127] The integral length of the cable is 553.766m.

[0128] In summary, the maximum cable length error is ±0.013m.

[0129] According to the manufacturing accuracy analysis in the factory, the maximum error is ±L / 50000, which is ±0.0108m, which is smaller than the cable length error analyzed above. Therefore, the linear shape of the main cable strands after installation in the saddle using the marking method meets the cable strand elevation deviation specified in the "Highway Engineering Quality Inspection and Assessment Standards", and this method is feasible.

[0130] 8. Cable Strand Line Shape Measurement Review

[0131] After the cable strands are installed, linear measurement is required. If the sag of the main cable installed by the marking method meets the requirements, no adjustment is required. If it does not meet the requirements, sag adjustment is required.

[0132] The sag adjustment is carried out at night when the temperature is relatively stable, there is no rain or fog, and the wind speed is less than level 5. The basic conditions for temperature stability are: the temperature difference of the cable strand in the length direction is ≤2℃, and the temperature difference of the cable strand in the cross section is ≤1℃.

[0133] The order of adjusting the cable strand sag is first the middle span, then the side span and finally the anchor span.

[0134] When adjusting the cable strands, the middle and side spans use the hand chain hoist installed on the portal frame in conjunction with the pulley block to retract and release the cable strands at the saddle position to achieve the purpose of adjusting the verticality. The anchor span uses the jack to adjust the cable strand tension. The basic method for adjusting the verticality of the main cable strand is: first accurately align the M6 ​​mark point of the cable strand with the arc vertex of the main rotating saddle on the rotating saddle side, and tighten and fix it with a wooden wedge, then adjust the position of the cable strand at the rotating saddle M5 on both sides, and then adjust the position of the cable strand in the main saddle M3 of the main tower until the verticality of the middle span meets the requirements and then fix it, then adjust the verticality of the side span cable strand, and fix it in the loose cable saddle after meeting the requirements, and finally adjust the anchor span. The anchor span cable strand uses a through-type jack to adjust its tension to meet the requirements of the monitoring unit. After the verticality adjustment is completed, the cable strand fixing mark should be made at the saddle to check whether there is slippage during the subsequent cable strand erection.

[0135] 9. Anchor span cable tension adjustment

[0136] After adjusting the sag of the middle and side spans, the anchor span tension is adjusted last. The anchor span tension is adjusted by using the tensioning tool installed on the anchor head to loosen and tighten the tie rod nut to make the anchor span cable tension meet the design requirements; in order to ensure the accuracy of the cable anchor span tension, the force measuring device of the monitoring unit is used for measurement and control, so that the anchor span cable tension value meets the design requirements.

[0137] After all main cable strands are installed and adjusted, zinc blocks are filled in the main and loose cable saddles, cover plates are installed, and the anchor rods are tensioned to the designed tonnage.

[0138] The cable linearity measurement is carried out using a total station with the trigonometric height method. In addition to the elevation of the cable, the offset of the main tower, the surface temperature of the cable and other data should also be determined.

[0139] In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A method for synchronously pulling and horizontally placing the main cable of a single-tower suspension bridge into the saddle, characterized in that: The cable strands are synchronously pulled from the revolving anchor to the opposite shore anchor. The main cable strand installation is divided into the reference cable strand installation and the general cable strand installation. The reference cable strand installation is carried out first, and then the general cable strand installation is carried out in the order of numbering. The installation of a single cable strand involves cable strand pulling, cable strand lateral movement, cable strand saddle entry, cable strand sag adjustment and anchor span tension adjustment. The specific process is as follows:

1. Construction preparation: before the cable strands are formally erected, the cable saddles are installed in place, the catwalks are erected, and the cable strand traction system is set up and debugged; 2. Cable traction: A single-line reciprocating traction system is used for erection. A traction system is arranged upstream and downstream. The cable laying area is set on the rotating anchor side. The winch of the traction system is set behind the anchor on the opposite bank. The two ends of the cable are pulled to the side of the cable saddle on the opposite bank through the traction system. The connection between the anchor heads at both ends of the cable and the traction system is released. The anchor heads at both ends are temporarily anchored, and the rotating sections of the cable are all pulled to the inside of the annular channel.

3. Lateral movement of cable strands: The cable strands that have been pulled are still supported on the drum. At this time, the cable strands are offset relative to the annular channel and cannot enter the saddle directly. The cable strands are lifted and pulled back from the inner side of the annular channel to the annular channel. Since the cable strands are pulled inside the annular channel before the lateral movement, the lateral movement of the cable strands can achieve the synchronous lateral movement and saddle entry operation of the annular channel and the tower top cable saddle.

4. Cable strands saddled: The order of cable strands saddled: saddled the rotating main saddle and the tower top main saddle at the same time → saddled the rotating side saddle → saddled the loose cable saddle. When saddled, align the marked points on the cable strands with the marked points on the saddle. Specific saddled methods: The main saddle is inserted horizontally from the middle of the saddle to both sides. When the cable strand is moved horizontally to the top of the annular channel, it is lowered into the annular channel. The lowering height is consistent with the height of the corresponding cable groove. The cable strand is pushed into the cable groove by horizontal pushing. The marking point of the cable strand is adjusted to align with the center point of the saddle and then wedged tightly with wooden wedges. The main saddle of the tower top is inserted from the side span to the middle span. When inserting the saddle, control the cable strands to prevent twisting, and gently lower the cable strands to the specified position in the cable saddle cable groove. After the marked point on the cable strands is aligned with the mark on the saddle, tighten it with a wooden wedge. The direction of entering the saddle on both the upstream and downstream sides is from the side span to the middle span. When entering the saddle, use the horizontal fall chain to adjust the cable strand into the saddle groove, and after the marked point on the cable strand is aligned with the center point of the saddle, use a wooden wedge to wedge it tightly. The direction of insertion of the loose cable saddle is from the anchor span side to the side span side. When inserting the loose cable saddle, align the mark on the cable strand with the mark on the saddle, and then tighten it with a wooden wedge.

5. Cable strand linear measurement and verification: After the cable strands are installed, the linear measurement is carried out. If the measurement results meet the main cable sag requirements, no adjustment is required. If not, sag adjustment is required.

6. Anchor span cable tension adjustment: Adjust the tension from both anchor head ends to make the anchor span cable tension meet the design requirements.

2. The method according to claim 1, characterized in that: Step 1: The cable saddle includes a revolving main saddle, two rotating cable saddles, a tower top main saddle and a loose cable saddle. The revolving main saddle and the revolving cable saddle are arranged in the annular channel of the revolving anchor. The two revolving cable saddles are symmetrically located upstream and downstream of the revolving main saddle. The tower top main saddle is arranged on the top of the bridge tower on the opposite bank, and the loose cable saddle is arranged between the bridge tower and the anchor on the opposite bank.

3. The method according to claim 1, characterized in that: Step 2: The cable traction system is mainly composed of a winch, a traction rope and a puller connected in series. The two ends of the traction rope are respectively wound into the main and auxiliary winches, one end is used for winding up for traction, and the other end is used for unwinding. The main and auxiliary winches are linked to make the traction rope reciprocate. The two ends of the cable are respectively pulled by the upstream traction system and the downstream traction system. The winches of the upstream and downstream traction systems are synchronously controlled by a synchronous controller to ensure synchronous traction of the upstream and downstream ends of the cable. After the catwalk is erected, the gantry guide wheel group is installed and the traction rope is supported on the guide wheel group to form a cable traction system. Cable strand rollers are installed on the catwalk, the tower top and the opposite bank anchor to realize cable strand traction and erection.

4. The method according to claim 1, characterized in that: Step 2: Synchronous pulling of upstream and downstream cables: Step 2.1, the main cable strand is coiled in half, and the main cable strand pay-off drum is a double-drag pay-off drum, which is used to support the main part of the cable strand coil and the folded ring part of the cable strand respectively; Step 2.2, arrange the cable tray behind the rotary anchor annular channel, the rotary main saddle and the rotating cable saddle are located inside the annular channel and are arranged on the inner wall of the annular channel, and the cable tray is installed on the cable tray frame by using on-site lifting equipment; Step 2.3, on the working surface of the slewing anchor, rollers are arranged along the inner side of the front of the annular channel. The arrangement of the rollers is consistent with the traction direction, so as to ensure that the two cables are released in the predetermined direction; Step 2.4, drag out the two anchor heads outside the cable drum, lift the two anchor heads at the same time with the lifting equipment and pull them forward, and connect the two anchor heads to the pullers of the upstream and downstream traction systems respectively; Step 2.5, start the winch of the traction system to traction the cable strands, separate the two anchor heads when they reach the position of the main saddle of the circular channel, and traction them along the front side of the circular channel to the upstream and downstream saddles, pass through the tower top and the loose cable saddle on the opposite bank, and finally anchor on the opposite bank; Step 2.6, when the anchor head reaches the predetermined position, release the connection between the anchor head and the puller, and temporarily anchor the anchor head on the opposite bank.

5. The method according to claim 4, characterized in that: During the traction process, pay attention to the remaining amount of the cable strand in the cable drum. When the folded section of the cable strand is completely out of the cable drum, lift the folded section of the cable strand and pull it back from the midpoint of the cable strand, i.e. the folding point, to ensure smooth traction until all the cables are pulled to the inner side of the annular channel.

6. The method according to claim 4, characterized in that: The pulling speed of the cable strand is controlled at 15-25m / min. At the turning and bending position, the speed is appropriately reduced to 5m / min.

7. The method according to claim 4, characterized in that: Step 3: The specific methods of lateral movement of the cable strand include: (3.1) Lateral movement of the cable strands at the slewing main saddle: First, use the winch on the gantry at the entrance of the catwalk on the slewing anchor side to pull the cable strands back to the slewing main saddle side, loosen the cable strands in the slewing section, and then perform the overall lateral movement; (3.2) Horizontal movement of the cable strand at the saddle: a gantry is set at the saddle position, an electric hoist is set on the gantry, and electric hoist slide rails are set on the longitudinal beams on both sides of the gantry. The cable strand is lifted by the electric hoist and then moves along the slide rail to achieve horizontal movement of the cable strand; (3.3) At a distance of 20 m on each side of the main saddle at the top of the tower, 20 m from the rear side of the loose cable saddle, and 2 m on each side of the rotating cable saddle, the cable strands are subjected to lateral displacement and reverse pulling.

8. The method according to claim 4, characterized in that: Step four, the rotating main saddle adopts a horizontal pushing device to horizontally enter the cable strand into the saddle, and a horizontal pushing device is set on the inner wall of the annular channel opposite to the rotating main saddle. The horizontal pushing device includes a vertical slide rail, a slider, a pull rope, an electric push rod and a support ring. The vertical slide rail is fixed on the inner wall of the annular channel, the slider is connected to the electric push rod, and the electric push rod moves up and down along the vertical slide rail through the slider. One end of the pull rope is fixed, and the other end is connected to the electric push rod. The support ring is set at the front end of the electric push rod, and the electric push rod is set horizontally to realize the pushing action in the horizontal direction.

9. The method according to claim 4, characterized in that: Step 5: The sag adjustment is carried out at night when the temperature is stable, there is no rain or fog, and the wind speed is less than level 5. The basic conditions for temperature stability are: the temperature difference of the cable strand in the length direction is ≤2°C, and the temperature difference of the cable strand in the cross section is ≤1°C; The order of adjusting the cable strand sag is first the middle span, then the side span, and finally the anchor span. The middle and side spans use the hand chain hoist installed on the gantry to cooperate with the pulley block to retract and release the cable strands at the saddle position to achieve the purpose of sag adjustment. The anchor span is adjusted by using the tension of the cable strands with jacks; The method for adjusting the sag of the main cable strand is: first accurately align the mark point of the strand at the midpoint of the arc of the main saddle of the revolving cable strand with the apex of the arc of the rotating cable saddle, and tighten and fix it with wooden wedges, then adjust the position of the strand at the midpoint of the arc of the rotating cable saddle on both sides, and then adjust the position of the strand at the apex of the main tower saddle until the sag of the middle span meets the requirements and then fix it, then adjust the sag of the side span strand, and fix it at the loose cable saddle after the sag design requirements are met, and finally adjust the anchor span. The anchor span strand uses a through-type jack to adjust the strand tension to meet the design requirements. After the sag adjustment is completed, the strand should be marked at the saddle to check for slippage during the subsequent cable strand erection.

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