A self-lifting device for replacing a sling and a working method thereof

Abstract

The application discloses a self-lifting device for replacing a sling and a working method thereof, and comprises a device body, wherein the device body comprises an expansion mechanism which is used for completing lateral deformation expansion of two sides of a sling to be replaced and lifting a bridge body stiffening beam below the sling. In the method, the minimum lifting amount Delta required by the sling to be replaced is calculated first, and stress variation range and limit bearing capacity of the sling at the design time are obtained. Thus, the expansion mechanism can be used to digest the force released when the minimum lifting amount Delta is reached by using the slings near the sling to be replaced. The locking mechanism is used as a lifting distance amplifying mechanism, and the expansion mechanism is expanded to the maximum distance, and the lifting distance formed by the whole sling reaches the minimum lifting amount Delta by being installed at a suitable position.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge engineering, and in particular to a self-lifting device for replacing a sling and a working method thereof. BACKGROUND

[0002] A single sling breakage accident may occur when a suspension bridge is affected by sudden events such as car collisions and fires. In addition, the anticorrosion problem of the suspension bridge sling has always been prominent due to its special use environment and high stress state. The service life of the ordinary anticorrosion treated sling is generally about 20-30 years, and even the specially treated one is difficult to exceed 40 years. At least 2-3 times of sling replacement will occur in the 100-year life cycle of bridge design. How to replace the damaged sling has become a problem to be solved by bridge engineers. Since the sling replacement hole is only considered at the beam end lug during the design of the suspension bridge, the sling replacement basically adopts the method of temporarily unloading the new sling with the aid of temporary cables.

[0003] For example, the patent with the application number CN202110404360.8, a method for replacing a sling of a suspension bridge with a single sling point: the sling is arranged between the main cable and the box girder, the upper and lower ends of the sling are connected by pin joints, the upper and lower end anchors of the sling are fork-shaped anchors, the tensioning force of the temporary sling and the unloaded replacement sling is uniformly tensioned in stages and synchronously, the temporary cable bears the tensioning force of the replacement sling until the tensioning force of the replacement sling reaches 0, the pin joint structure of the upper and lower ends of the replacement sling is assisted to be disassembled by a pushing device to remove the replacement sling, and after the new sling is replaced, the new sling is uniformly tensioned in stages and synchronously and the temporary sling is unloaded to make the new sling bear the load.

[0004] The basic principle of the above-mentioned temporary cable assisted unloading and replacement of the new sling is to newly add one or two large temporary slings next to the replacement point to vertically lift the stiffened beam, so that the old sling at the replacement point is unloaded and empty to replace the sling. The process flow is as follows: construction platform preparation → temporary sling, temporary sling clamp, jack installation → temporary sling jack tensioning and unloading → old sling removal → new sling installation → temporary sling system unloading → replacement tool removal, etc. The biggest problem of the traditional method of replacing the sling is that the removal of the old sling needs to borrow large-scale lifting equipment, large-scale temporary auxiliary slings, large-scale temporary cable clamps, and temporary anchoring devices to lift the sling area beam segment to make it empty, and the cable force of the sling to be replaced is transferred to the temporary sling. The process is complex and inefficient. Since the length of each replacement sling is different, the temporary sling also needs to be matched one by one, resulting in a significant increase in the cost of replacing the sling. With the gradual improvement of the intelligent design of the bridge, the automatic replaceable problem of the sling has been put on the agenda.

[0005] The cable system bridge considers the possibility of broken cable and replacement of the sling during design. When the broken cable and replacement of the sling appear in the allowable condition, the force released by the broken cable and replacement of the sling is absorbed by the deformation and stress adjustment of other parts of the bridge, so the stress variation range and ultimate bearing capacity of the main cable, sling, cable clamp and stiffening beam are considered during design. For example, the design safety factor of the sling and cable clamp of the suspension bridge is more than 3.5 to ensure safety during the broken cable and replacement of the sling. Generally, the elastic elongation of the sling is small, and the elastic elongation of the 5m long short sling is only about 6mm, and the elastic elongation of the 100m long sling is only about 140mm. Even if a sling is broken, the safety factor is more than 1.75, and the increase of the elastic elongation is controlled within 1 times. Therefore, only a small displacement of the stiffening beam is needed to make the sling appear empty. Based on this, a new replacement sling device and its application method are developed. SUMMARY

[0006] In view of the prior art mentioned in the background art, the removal of the old cable needs to use large lifting equipment, large temporary auxiliary sling, large temporary cable clamp and temporary anchoring device to pull up the sling area beam segment to make it empty, which is complex and inefficient. The expansion mechanism provided by the application uses the remaining slings to process the emptying of the sling to be replaced, reduces the need for temporary slings and lifting equipment, significantly improves the replacement efficiency and overall cost, and has excellent practical application effect.

[0007] The second application object of the application is to solve the problem of significant increase of replacement cost caused by the fact that the temporary slings need to be matched one by one due to the different lengths of each sling to be replaced.

[0008] In order to achieve the above object, the application adopts the following technical scheme:

[0009] A self-lifting device for replacing a sling, comprising a device body, wherein the device body comprises:

[0010] The expansion mechanism is used for transversely deforming and expanding the two cables on both sides of the cable to be replaced and lifting the bridge body stiffener below the cable. The bridge body stiffener is a component mainly used for supporting and transferring load and is a main component for bearing vehicle load and other horizontal forces, and the bridge body stiffener is fixed by a plurality of cables. The expansion mechanism provided by the application ingeniously uses the load bearing margin of other cables near the cable to be replaced, transversely deforms and expands the other cables to vertically lift the bridge body stiffener, so that the cable to be replaced is not stressed due to emptying, thereby achieving the'self-lifting' of the bridge body stiffener to facilitate the replacement of the cable without the need for jacking equipment and temporary cables and anchoring devices. Of course, the selection of other cables needs to be based on bridge parameters and the emptying distance of the cable to be replaced and the like, and the number of expansion mechanisms installed on each cable can also be adjusted according to the above data to ensure that the bearing capacity of each cable during the emptying of the cable to be replaced does not exceed the warning value.

[0011] Further, the expansion mechanism comprises two expansion cable sleeves connected to the cables on both sides of the cable to be replaced, a longitudinal pull rod is arranged between the two expansion cable sleeves, two hinged joints are arranged on the longitudinal pull rod, a connecting rod is hinged to the two expansion cable sleeves on the two sides of each hinged joint, one of the two hinged joints is a moving joint, a control motor is arranged on the moving joint, and the control motor can drive the moving joint to move along the extension direction of the longitudinal pull rod. By using the basic principles of self-balancing and transverse prestress, the device body is arranged on the adjacent cables of the left and right beam sections of the cable to be replaced, two or more cables of the adjacent beam sections of the cable to be replaced are lifted by the self-lifting device, the cable to be replaced is emptied, and the cable is replaced in turn, so that the purpose of automatically replacing all cables is achieved; since the sizes of the connecting rods are consistent, the two hinged joints and the connecting rods on the two sides form a variable rhombus mechanism, the relative distance between the two hinged joints is changed by moving the moving joint on the longitudinal pull rod, the transverse expansion of the two expansion cable sleeves attached to the two cables is realized, the two cables are expanded outward and the bridge body stiffener is lifted, and the emptying of the cable to be replaced is realized.

[0012] As a preferred, the device body comprises:

[0013] The locking mechanism is used for locking the distance between the cables on both sides of the cable to be replaced, and is arranged above or below the expansion mechanism. The locking mechanism can lock the distance between the cables at a preset position, so as to double the lifting height of the expansion mechanism. Specifically, when the distance between the expansion mechanism and the beam end ear plate or the cable clamp ear plate is shortened by the locking mechanism, the lifting distance is doubled when the expansion mechanism is transversely expanded by the same width.

[0014] As preferred, the locking mechanism comprises two locking cable sleeves respectively connected to the two sides of the cable to be replaced, and a movable connecting rod is hingedly arranged between the two locking cable sleeves. The locking mechanism is fixed with the cable through the locking cable sleeves, and the relative distance between the two locking cable sleeves is determined through the movable connecting rod, so as to ensure that the transverse distance of the two locking cable sleeves is unchanged. The hinged connection between the movable connecting rod and the locking cable sleeve can make the locking cable sleeve rotate with the cable deflection angle after the expansion mechanism is actuated, so as to avoid hard folding of the cable and bending of the cable, and to avoid stress concentration of the cable and reduce the structural strength.

[0015] As preferred, the expansion cable sleeve and the locking cable sleeve have the same structure, and the expansion cable sleeve comprises a support head connected to the cable. A cover plate is assembled on the side of the support head and is used to press and fix the cable. The expansion cable sleeve and the locking cable sleeve have the same structure and consistent functions, so as to ensure that the expansion mechanism and the locking mechanism are stationary relative to the cable when the moving knot driven by the control motor moves, and to avoid the influence of sliding on the lifting effect. The cover plate is detachably connected to the support head, so as to ensure the press and fixation between the cover plate and the cable sleeve.

[0016] As preferred, a trumpet slot is arranged on the inner side of the support head, and the trumpet slot is used to clasp and connect the cable. The trumpet slot is gradually narrowed and tightened from the outside to the inside, so as to ensure that the support head is tightly clamped with the cable.

[0017] The application also discloses a working method of the self-lifting device for replacing the cable.

[0018] S1: calculating the minimum lifting amount Δ required for lifting the bridge body stiffening beam due to the emptying of the cable to be replaced;

[0019] S2: selecting the number of cables on both sides of the cable to be replaced according to the minimum lifting amount Δ calculated in S1, and installing the expansion mechanism on the selected cables except the cable to be replaced;

[0020] S4: judging whether the locking mechanism is installed according to the minimum lifting amount Δ calculated in S1, the position of the expansion mechanism and the length of the cable, and the number of the locking mechanism is determined according to the calculation requirement;

[0021] S5: after the expansion mechanism and the locking mechanism are installed, the control motors of the expansion mechanisms on the cables are synchronously actuated, the cables are transversely expanded and deformed to make the cable to be replaced empty;

[0022] S6: replacing the cable;

[0023] S7: the control motors of the expansion mechanisms on the cables are synchronously reset, and the new cable is stressed;

[0024] S8: disassembling the expansion mechanisms and the locking mechanisms;

[0025] S9: Repeat S1-S8 to replace other replacement sling.

[0026] In the method, the minimum lifting amount Δ required for the replacement sling to be replaced to be empty is calculated first, and the stress variation range and the ultimate bearing capacity of the sling at the design time are obtained; thus, the force released when the minimum lifting amount Δ is reached can be absorbed by the slings near the replacement sling. The locking mechanism acts as a lifting distance amplification mechanism, and by being installed at a suitable position, the lifting distance formed by the entire sling when the expansion mechanism expands to the maximum distance reaches the minimum lifting amount Δ.

[0027] When the expansion mechanism and the locking mechanism are installed and start to work, the control motors need to be kept synchronized to avoid uneven force between the slings and cause breakage and other problems. The method does not need to use large jacking equipment to jacking the bridge body stiffening beam, nor does it need to install large temporary auxiliary slings, large temporary sling clamps, and temporary anchoring devices to pull up the sling area beam segment to make the replacement sling empty. The method significantly optimizes the sling replacement method, realizes the self-lifting of the bridge body, reduces the cost of the construction site, and more importantly, reduces the participation of the temporary sling through the locking mechanism, so that the device body can perform self-lifting of the bridge body to complete the sling replacement work, thereby solving the second invention purpose of the application.

[0028] Therefore, the application has the following beneficial effects:

[0029] 1) Large temporary auxiliary cables and large temporary cable clamps are saved, the influence of the temporary cable clamp on the main cable protection is avoided, and high-altitude operation is greatly reduced.

[0030] 2) The expansion mechanism can greatly reduce the expansion force, which is only about 1 / 8 of the auxiliary cable unloading method cable force;

[0031] 3) The locking mechanism can multiply the lifting amount obtained by the transverse expansion deformation of the expansion mechanism, which is particularly suitable for long slings and significantly improves the versatility of the device;

[0032] 4) The device of the application is assembled from standard parts, is easy to disassemble, and the machining precision and quality are easy to control. Only about 20 sets of device bodies are needed to complete the replacement of the entire bridge (the end sling needs to be jacked up) for a kilometer-level suspension bridge, which realizes the fastest and least expensive replacement of the sling.

[0033] 5) The control motor realizes the high automation of the expansion action and can be installed anywhere at any time to expand the sling. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The initial structure diagram of the application in Example 2.

[0035] Figure 2An expanded structure diagram of the application in Example 2.

[0036] Figure 3 An action process diagram of the application in Example 1.

[0037] Figure 4 An action process diagram of the application in Example 1.

[0038] Figure 5 An exploded diagram of the application in Example 2.

[0039] Figure 6 An assembly diagram of the application in Example 2.

[0040] Figure 7 An operation diagram of the application in Example 3.

[0041] Figure 8 An operation diagram of the application in Example 4.

[0042] Reference numerals

[0043] 1. Main cable, 2. Cable clamp, 3. Stiffening beam, 4. Suspension cable, 5. Expansion mechanism, 6. Locking mechanism, 7 Cable sleeve, 71. Expansion cable sleeve, 72. Locking cable sleeve, 8. Connecting rod, 9. Longitudinal pull rod, 10. Hinged knot, 101. Moving knot, 11. Control motor, 12. Support head, 13. Cover plate. DETAILED DESCRIPTION

[0044] The application will be further described below in conjunction with the specific embodiments and the accompanying drawings. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0045] Example 1

[0046] As shown in Figure 3 , 4 A self-lifting device for replacing suspension cable, comprising a device body, the device body comprising:

[0047] Expansion mechanism, complete the transverse deformation expansion of the two sides of the suspension cable of the suspension cable to be replaced and lift the bridge body stiffening beam below the suspension cable.

[0048] The expansion mechanism comprises two expansion cable sleeves connected to the two sides of the cable to be replaced, a longitudinal pull rod 9 arranged between the two expansion cable sleeves, two hinged knots arranged on the longitudinal pull rod, a connecting rod 8 hinged to the two expansion cable sleeves arranged on the two sides of each hinged knot, and a moving knot 101 arranged in one of the two hinged knots, wherein a control motor 11 is arranged on the moving knot, and the control motor can drive the moving knot to move along the extension direction of the longitudinal pull rod.

[0049] The bridge body stiffening beam is a component mainly used for supporting and transmitting load, and is the main component for bearing vehicle load and other horizontal forces. The bridge body stiffening beam is fixed by a plurality of groups of cables. The lower end of the cable 4 is connected to the bridge body stiffening beam 3, and the upper end is connected to an ear plate through a cable clamp 2. The ear plate is fitted and installed on the main cable 1. The expansion mechanism 5 provided in the application ingeniously utilizes the load bearing margin of other cables near the cable to be replaced, and realizes the vertical lifting of the bridge body stiffening beam by expanding the other cables in the transverse direction, so that the cable to be replaced is not under stress due to the emptying. Therefore, the bridge body stiffening beam can be lifted automatically to facilitate the replacement of the cable without the need for jacking equipment and temporary cables and anchoring devices. Of course, the selection of other cables needs to be based on the bridge parameters and the emptying distance of the cable to be replaced, and the number of expansion mechanisms installed on each cable can also be adjusted according to the above data to ensure that the bearing capacity of each cable does not exceed the warning value during the emptying of the cable to be replaced. By utilizing the basic principles of self-balancing and transverse prestress, the device body is arranged on the adjacent cables of the left and right beam sections of the cable to be replaced. The two or more cables of the adjacent beam sections of the cable to be replaced are lifted by the self-lifting device, so that the cable to be replaced is emptied. After the cable is replaced, the process is repeated in sequence, so as to achieve the purpose of automatic replacement of all cables. Since the sizes of the connecting rods are consistent, the two hinged knots and the connecting rods on the two sides form a variable rhombus mechanism. By moving the moving knot on the longitudinal pull rod, the relative distance between the two hinged knots is changed, so as to realize the transverse expansion of the two expansion cable sleeves attached to the two cables, so that the two cables expand outward and lift the bridge body stiffening beam, and the emptying of the cable to be replaced is realized. In the embodiment, the longitudinal pull rod is a high-strength threaded pull rod, and the two hinged knots are threadedly connected to the longitudinal pull rod.

[0050] Embodiment 2

[0051] As Figure 1 , 2As shown, in the embodiment, the device body is additionally provided with a locking mechanism 6 for locking the distance between the two sides of the hoisting cable to be replaced. The locking mechanism is arranged above or below the expansion mechanism. The locking mechanism can lock the distance between the hoisting cables at a preset position, thereby proportionally enlarging the lifting height of the expansion mechanism. Specifically, when the distance between the expansion mechanism and the beam end ear plate or the cable clamp ear plate is shortened through the locking mechanism, a greater lifting distance can be obtained when the expansion mechanism is expanded laterally by the same width. In the embodiment, the device body is composed of one expansion mechanism and one locking mechanism. The setting of the locking mechanism can multiply the lifting height. For example, when the distance between the mechanisms L = 2000 mm and the distance D = 300 mm are expanded, the maximum lifting height that can be achieved by each set of lifting device is about 45 mm. For short hoisting cables with a length of ≤ 5 m, only one expansion mechanism can be arranged, and the beam end ear plate and the cable clamp ear plate are used as the locking mechanism. For long hoisting cables, multiple pairs of self-lifting devices can be arranged in series to further multiply the lifting height. Figure 5 、 6 As shown, the expansion cable sleeve 71 and the locking cable sleeve 72 have the same structure and are both cable sleeves 7. The expansion cable sleeve includes a support head 12 connected to the hoisting cable. A cover plate 13 is arranged on the side of the support head. The cover plate is fixed to the hoisting cable by bolt pressing. The expansion cable sleeve and the locking cable sleeve have the same structure and consistent functions, which can ensure that the expansion mechanism and the locking mechanism remain stationary relative to the hoisting cable when the moving knot is driven to move by the control motor, thereby avoiding the influence of sliding on the lifting effect. The cover plate can be detachably connected to the support head to ensure pressing and fixing between the cable sleeve. The inner side of the support head is provided with a trumpet slot, which is engaged with the hoisting cable. The trumpet slot gradually narrows from the outside to the inside, which can ensure that the support head and the hoisting cable are tightly clamped.

[0052] Embodiment 3

[0053] As shown Figure 7As shown, this embodiment provides a method for automatically replaceable slings and a self-lifting device for replacing short slings. Assuming short sling N# is the target sling, considering its small deformation and the small influence range of the stiffening beam's deformation, the sling replacement process is as follows: First, calculate the minimum lifting amount Δ required to detach short sling N#. Then, install the assembly expansion mechanism 5 and locking mechanism 6 on slings N-1# and N+1#. A set of self-lifting devices is sufficient based on the lifting amount Δ. Start the control motor 11; the expansion mechanism begins to work, slings N-1# and N+1# gradually expand, the stiffening beam 3 slowly lifts, and short sling N# gradually relaxes until it is detached. After replacing short sling N#, start the control motor 11 again; short slings N-1# and N+1# gradually retract, the stiffening beam 3 slowly lowers, and the new sling N# begins to taut and bear force. After reaching the target position, stop the motor, disassemble the expansion mechanism and locking mechanism, and transfer them to the vicinity of the next target sling. This process is repeated in sequence, thereby achieving the goal of automatically replacing other short slings.

[0054] Example 4

[0055] like Figure 8 As shown, this embodiment provides a method for automatically replaceable slings and a self-lifting device for replacing long slings. Considering the large deformation and the wide range of influence of the stiffening beam deformation, assuming that the N# long sling is the target sling, the sling replacement process is as follows: First, calculate the minimum lifting amount Δ required to detach the N# long sling. Then, install the assembly expansion mechanism 5 and the locking mechanism 6 on the N-2#, N-1#, N+1#, and N+2# long slings. The purpose is to ensure that the force difference between adjacent slings is not too large. Depending on the size of the lifting amount Δ at different lifting points, one or more sets of self-lifting devices can be set. Start the control motor 11, the expansion mechanism starts working, the N-2#, N-1#, N+1#, and N+2# long slings 4 gradually expand, the stiffening beam 3 is slowly lifted, and the N# sling 4 slowly relaxes until it is detached. After replacing the N# long sling, restart the control motor 11. The N-2#, N-1#, N+1#, and N+2# long slings 4 gradually retract, the stiffening beam 3 slowly lowers, and the new N# sling begins to taut and bear force. Once it reaches the target position, the control is stopped, the expansion mechanism and locking mechanism are disassembled, and the sling is moved and installed near the next target sling. This cycle is repeated to achieve the automatic replacement of other long slings.

[0056] In addition to the above embodiments, within the scope disclosed in the claims and specification of this invention, the technical features of this invention can be reselected and combined to form new embodiments. These can be achieved by those skilled in the art without creative effort. Therefore, these embodiments not described in detail in this invention should also be regarded as specific embodiments of this invention and within the protection scope of this invention.

Claims

1. A self-lifting device for replacing a sling, characterized in that The device comprises a device body, which comprises: The expansion mechanism is used to expand the transverse deformation of the two side cables of the cable to be replaced and to lift the bridge body stiffener under the cable; The expansion mechanism comprises two expansion cable sleeves connected to the two side cables of the cable to be replaced, a longitudinal pull rod arranged between the two expansion cable sleeves, two hinged knots arranged on the longitudinal pull rod, a connecting rod hinged to the two expansion cable sleeves arranged on both sides of the two hinged knots, and a moving knot arranged in the two hinged knots, and a control motor arranged on the moving knot; The locking mechanism is used to lock the distance between the two side cables of the cable to be replaced, and is arranged above or below the expansion mechanism.

2. A self lifting device for replacing a sling according to claim 1, characterized in that The control motor can drive the moving knot to move along the extension direction of the longitudinal pull rod.

3. A self lifting device for replacing a sling as claimed in claim 1, wherein, The locking mechanism can lock the distance between the cables at a preset position, thereby doubling the lifting height of the expansion mechanism.

4. A self lifting device for replacing a sling according to claim 3, characterized in that The locking mechanism comprises two locking cable sleeves connected to the two side cables of the cable to be replaced, and a movable connecting rod hingedly arranged between the two locking cable sleeves.

5. A self lifting device for replacing a sling according to claim 4, characterized in that The expansion cable sleeve and the locking cable sleeve have the same structure, the expansion cable sleeve comprises a support head connected to the cable, and a cover plate is arranged on the side of the support head.

6. A self-energizing device for replacing a sling according to claim 5, characterized in that The inside of the support head is provided with a trumpet slot for clamping the cable.

7. A method of operating a self-elevating device for replacing a sling according to any one of claims 1-6, characterized in that, The method comprises the following steps: S1: calculating the minimum lifting amount Δ required for the bridge body stiffener to be lifted by the emptying cable to be replaced; S2: selecting the number of the two side cables of the cable to be replaced according to the minimum lifting amount Δ calculated in S1, and installing the expansion mechanism on the selected cables except the cable to be replaced; S4: judging whether to install the locking mechanism according to the minimum lifting amount Δ calculated in S1, the position of the expansion mechanism and the length of the cable, and the number of the locking mechanism is determined according to the calculation requirement; S5: after the expansion mechanism and the locking mechanism are installed, the control motors of the expansion mechanisms on each cable are synchronously actuated to expand the transverse deformation of the cable and make the cable to be replaced empty; S6: replacing the cable; S7: synchronously resetting the control motors of the expansion mechanisms on each cable, and stressing the new cable; S8: disassembling each expansion mechanism and locking mechanism; S9: repeating the actions in S1-S8 to replace other cables to be replaced.

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