Method for replacing a suspender of a tied arch bridge

Abstract

The application discloses a method for replacing a suspender of a tied-arch bridge, which comprises the following steps: (1) setting temporary facilities at the connection between the upper end of the original suspender and the arch rib; (2) setting a lower anchorage structure at the connection between the lower end of the original suspender and the beam body; (3) lifting the temporary suspender to make the original suspender in a stress-free state; (4) removing the upper end of the original suspender by using automatic loading and unloading equipment; (5) installing a new suspender; (6) adjusting the new suspender; (7) completing the replacement of the suspender, and removing the temporary suspender and the temporary facilities. The method can avoid damaging the structure of the tied-arch bridge, improve the stress condition of the suspender, and facilitate the replacement of the suspender in the later period; the influence on the traffic of the bridge during the replacement period is small, and the method has good adaptability, fast construction, high efficiency, convenient operation, safety and reliability, and good economy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge construction, in particular to a method for replacing a suspender of a tied-arch bridge. BACKGROUND

[0002] The tied-arch bridge has the advantages of reasonable structure, clear stress and large vertical stiffness. The bridge type is not only advanced in technical and economic indicators, but also economical in cost, and the bridge type is beautiful, reflecting the unity of force and beauty, and the harmony of structural form and environment. The suspender of the tied-arch bridge suspends the longitudinal beam and the cross beam system under the arch rib and is a main tensile member. The bridge deck load is transmitted to the arch rib through the suspender and the bridge deck system. Due to the defects of the traditional suspender in the anchoring system, the cable structure and the corrosion prevention scheme, the suspender is damaged prematurely. The main diseases of the suspender include failure of the protection structure, corrosion of the steel wire or steel strand, failure of the upper and lower anchors, and suspender fracture.

[0003] In order to make the suspender, the arch rib and the beam body form a unified rigid body and improve the integrity, the steel bars at both ends of the suspender are welded or anchored to the arch rib and the beam body respectively. However, this connection mode brings many inconveniences to the replacement of the suspender. When the traditional replacement method is used, many factors affect the replacement of the suspender in the later period, the arch rib and the beam body structure need to be damaged, so the damage is large, the technical requirement is high, the construction process is complex, the replacement is difficult, the replacement efficiency is low. If the replacement progress of the suspender is to be accelerated, only the way of increasing the temporary suspender, the operating personnel and the machinery is adopted, which causes the waste of cost, and the simultaneous replacement of multiple suspenders leads to more complex structure stress and increases the risk of suspender replacement. SUMMARY

[0004] In order to solve the defects in the prior art, the present application provides a method for replacing a suspender of a tied-arch bridge. The method of the present application can avoid damage to the structure of the tied-arch bridge, improve the stress condition of the suspender, facilitate the replacement of the suspender in the later period, has less impact on the traffic of the bridge during the replacement period, and has good adaptability, fast construction, high efficiency, convenient operation, safety and reliability, and good economy.

[0005] To achieve the above-mentioned purpose, the present application provides a method for replacing a suspender of a tied-arch bridge, comprising the following steps:

[0006] (1) setting a temporary facility at the connection between the upper end of the original suspender and the arch rib; the temporary facility comprises an arch rib temporary anchoring seat and an automatic loading and unloading device arranged on a lifting frame, the arch rib temporary anchoring seat is installed on the arch rib and connected to the upper end of the temporary suspender through an anchoring plate;

[0007] (2) setting a lower anchor structure at the connection between the lower end of the original suspender and the beam body; the lower anchor structure is fixedly connected with the anchoring structure of the lower end of the original suspender on the beam body and is fixedly arranged on the beam body;

[0008] (3) lifting the temporary suspender, making the original suspender in a stress-free state; connecting the upper end of the temporary suspender to the temporary anchoring seat of the arch rib by the automatic loading and unloading device, and then connecting the lower end of the temporary suspender to the lower anchoring structure, so that the temporary suspender is stressed;

[0009] (4) removing the original suspender; removing the upper end of the original suspender by the automatic loading and unloading device; and then cutting the original suspender at the connection between the lower end of the original suspender and the anchoring structure, without damaging the anchoring structure of the lower end of the original suspender on the beam body;

[0010] (5) installing the new suspender; lifting the new suspender, and installing the upper end of the new suspender at the connection between the original suspender and the arch rib by the automatic loading and unloading device; and then connecting the lower end of the new suspender to the lower anchoring structure;

[0011] (6) adjusting the new suspender; according to the designed suspender tensioning force, the new suspender is tensioned in stages until the designed value is reached; and then the lower end of the new suspender is completely anchored and connected to the lower anchoring structure, so that it reaches the normal use stress state;

[0012] (7) completing the suspender replacement, and removing the temporary suspender and the temporary facilities.

[0013] Preferably, in the step (1), the construction personnel stand on the lifting frame, and the arch rib temporary anchoring seat is installed on the arch rib when the lifting frame is lifted to the height position of the upper end of the suspender, and the installation position is adjacent to the connection between the upper end of the original suspender and the arch rib; the automatic loading and unloading device can move on the lifting frame.

[0014] Preferably, in the step (2), the lower anchoring structure comprises an I-shaped anchoring upper connecting body, an anchoring connecting rod and an I-shaped anchoring lower connecting body, the I-shaped anchoring upper connecting body is welded with the anchoring structure on the beam body, and an anchoring connecting structure is arranged on the upper surface for connecting the lower end of the temporary suspender and the new suspender; four through-hole jacks are installed at the lower surface of the I-shaped anchoring upper connecting body, two of which are used for tensioning the temporary suspender, and the other two are used for tensioning the new suspender; the I-shaped anchoring upper connecting body and the I-shaped anchoring lower connecting body are connected into one body through the anchoring connecting rod, and the I-shaped anchoring lower connecting body is arranged at the lower part of the beam body.

[0015] Preferably, in the step (3), the upper end of the temporary suspender is connected to the anchoring plate of the arch rib temporary anchoring seat, and the lower end of the temporary suspender is connected to the anchoring connecting structure of the lower anchoring structure; by monitoring the cable force of the original suspender, the dead load internal force of the original suspender is obtained, the internal force is loaded and released in stages, and the cable force of the original suspender is gradually transferred to the temporary suspender; and then the temporary suspender is tensioned in stages by the two through-hole jacks, and the tensioning control is 0, 15%, 35%, 50%, 70% and 100% in turn.

[0016] In any of the above schemes, preferably, in the step (4), the original suspender is cut off by using electric welding cutting, and the removed original suspender is removed by using a crane and placed in a designated area.

[0017] In any of the above schemes, preferably, in the step (5), the lower end of the new suspender is connected to the corresponding anchoring connection structure of the I-shaped anchoring connector.

[0018] In any of the above schemes, preferably, in the step (6), the new suspender is tensioned while the cable force of the temporary suspender is released in stages to achieve equivalent conversion of the cable force of the temporary suspender to the new suspender; after the new suspender is tensioned to reach the design value and the elevation adjustment is appropriate, the lower end of the new suspender is completely anchored and connected to the lower anchoring structure.

[0019] The method of the present application has the following advantages:

[0020] 1. The method of the present application can avoid damage to the structure of the tied arch bridge, improve the stress condition of the suspender, and facilitate the replacement of the suspender in the later period; the traffic impact on the bridge during the replacement period is small, and the construction has good adaptability, fast construction, high efficiency, easy operation, safety and reliability, and good economy.

[0021] 2. The method of the present application does not need to drill holes in the original structure of the tied arch bridge, avoids damage to the structure, facilitates the replacement of the suspender, and improves the stress condition of the suspender during the construction process, facilitating the replacement of the suspender in the later period. Moreover, the common lower anchoring structure is used when installing the temporary suspender and the new suspender, reducing the use of additional structures, reducing construction cost and engineering quantity, and greatly improving construction efficiency.

[0022] 3. Most of the construction process of the present application is completed on the bridge deck, avoiding damage to the environment; the old suspender does not need to be taken out from the beam end, and automatic loading and unloading equipment is used to disassemble and assemble the upper end of the suspender, reducing the construction difficulty, shortening the construction period, and improving the safety factor of high-altitude operation; the replacement construction of the suspender in the later period is more convenient and faster.

[0023] 4. The present application is suitable for the replacement of the suspender of the tied arch bridge, the construction tool structure is simple, the total cost is low, the continuous tensioning can be easily realized, the difficulty of force conversion operation is reduced. The vehicle passing clearance above the bridge deck has no over-limit facilities, and does not affect the traffic passing on the bridge deck; the construction process is mature, the working condition is stable, the control index is clear, and the construction method has small risk. The arch rib does not need to be holed, the arch rib structure and appearance are protected; the old suspender is not taken out from the beam body, which saves time and effort, and the anchoring structure of the lower end of the old suspender left in the beam body can increase the structural strength of the beam body. The safety and controllability of the suspender replacement are realized, the application technology is worth popularizing, and has broad application prospect. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be described in detail below with reference to the specific embodiments of the present application. However, the following embodiments are only used to understand the present application, and the embodiments in the present application and the features in the embodiments can be combined with each other, and the present application can be implemented in various different ways limited and covered by the claims.

[0025] Embodiment 1

[0026] A method for replacing a suspender of a tied-arch bridge, comprising the following steps:

[0027] (1) setting a temporary facility at a connection position between an upper end of an original suspender and an arch rib; the temporary facility comprises an arch rib temporary anchoring seat and an automatic loading and unloading device arranged on a lifting frame, the arch rib temporary anchoring seat is installed on the arch rib and connected to an upper end of a temporary suspender through an anchoring plate;

[0028] (2) setting a lower anchoring structure at a connection position between a lower end of the original suspender and a beam body; the lower anchoring structure is fixedly connected to an anchoring structure of the lower end of the original suspender on the beam body and is fixedly arranged on the beam body;

[0029] (3) lifting the temporary suspender to make the original suspender in a stress-free state; connecting the upper end of the temporary suspender to the arch rib temporary anchoring seat through the automatic loading and unloading device, and then connecting the lower end of the temporary suspender to the lower anchoring structure, so that the temporary suspender is stressed;

[0030] (4) removing the original suspender; removing the upper end of the original suspender by using the automatic loading and unloading device; and then cutting the original suspender at a connection position between the lower end of the original suspender and the anchoring structure without damaging the anchoring structure of the lower end of the original suspender on the beam body;

[0031] (5) installing a new suspender; lifting the new suspender and installing the upper end of the new suspender at the connection position between the original suspender and the arch rib by using the automatic loading and unloading device; and then connecting the lower end of the new suspender to the lower anchoring structure;

[0032] (6) adjusting the new suspender; grading tensioning the new suspender according to a designed suspender tensioning force until the designed value is reached; and then completely anchoring the lower end of the new suspender to the lower anchoring structure to make the new suspender reach a normal use stressed state;

[0033] (7) completing the replacement of the suspender and removing the temporary suspender and the temporary facility.

[0034] In the step (1), a construction worker stands on the lifting frame, waits for the lifting frame to be lifted to a height position of the upper end of the suspender, and installs the arch rib temporary anchoring seat on the arch rib, and the installation position is adjacent to the connection position between the upper end of the original suspender and the arch rib; the automatic loading and unloading device can move on the lifting frame.

[0035] In the step (2), the lower anchorage structure comprises an I-shaped anchoring upper connecting body, an anchoring connecting rod and an I-shaped anchoring lower connecting body, the I-shaped anchoring upper connecting body is welded with the anchoring structure on the beam body, and an anchoring connecting structure is arranged on the upper surface for connecting the lower end of the new suspender; four through-hole jacks are installed at the lower surface of the I-shaped anchoring upper connecting body, two of which are used for tensioning the temporary suspender, and the other two are used for tensioning the new suspender; the I-shaped anchoring upper connecting body and the I-shaped anchoring lower connecting body are connected into one body through the anchoring connecting rod, and the I-shaped anchoring lower connecting body is arranged at the lower part of the beam body.

[0036] In the step (3), the upper end of the temporary suspender is connected to the anchoring plate of the temporary anchoring seat of the arch rib, and the lower end of the temporary suspender is connected to the anchoring connecting structure of the lower anchorage structure; the cable force of the original suspender is obtained by monitoring the cable force of the original suspender, the internal force of the constant load of the original suspender is gradually transferred to the temporary suspender by gradually loading and releasing the internal force; then the temporary suspender is tensioned by two through-hole jacks, and the step-by-step tensioning control is 0, 15%, 35%, 50%, 70% and 100% in turn.

[0037] In the step (4), the original suspender is cut off by electric welding cutting, and the removed original suspender is removed by a crane and placed in a designated area.

[0038] In the step (5), the lower end of the new suspender is connected to the corresponding anchoring connecting structure of the I-shaped anchoring upper connecting body.

[0039] In the step (6), the new suspender is tensioned while the cable force of the temporary suspender is gradually released, so that the cable force of the temporary suspender is equivalent to the new suspender; after the new suspender is tensioned to the design value and the elevation adjustment is appropriate, the lower end of the new suspender is completely anchored and connected with the lower anchorage structure.

[0040] Example 2

[0041] A suspender replacement method of a tied arch bridge, comprising the following steps:

[0042] (1) A temporary facility is arranged at the connection between the upper end of the original suspender and the arch rib; the temporary facility comprises a temporary anchoring seat of the arch rib and an automatic loading and unloading device arranged on a lifting frame, the temporary anchoring seat of the arch rib is installed on the arch rib and connects the upper end of the temporary suspender through an anchoring plate;

[0043] (2) A lower anchorage structure is arranged at the connection between the lower end of the original suspender and the beam body; the lower anchorage structure is fixedly connected with the anchoring structure of the lower end of the original suspender on the beam body and is fixedly arranged on the beam body;

[0044] (3) lifting the temporary suspender, making the original suspender in a stress-free state; connecting the upper end of the temporary suspender to the temporary anchoring seat of the arch rib by the automatic loading and unloading device, and then connecting the lower end of the temporary suspender to the lower anchoring structure, so that the temporary suspender is stressed;

[0045] (4) removing the original suspender; removing the upper end of the original suspender by the automatic loading and unloading device; and then cutting the original suspender at the connection between the lower end of the original suspender and the anchoring structure, without damaging the anchoring structure of the lower end of the original suspender on the beam body;

[0046] (5) installing the new suspender; lifting the new suspender, and installing the upper end of the new suspender at the connection between the original suspender and the arch rib by the automatic loading and unloading device; and then connecting the lower end of the new suspender to the lower anchoring structure;

[0047] (6) adjusting the new suspender; according to the designed suspender tensioning force, the new suspender is tensioned in stages until the designed value is reached; and then the lower end of the new suspender is completely anchored and connected to the lower anchoring structure, so that it reaches the normal use stress state;

[0048] (7) completing the suspender replacement, and removing the temporary suspender and the temporary facilities.

[0049] In the step (1), the construction personnel stand on the lifting frame, and install the temporary anchoring seat of the arch rib on the arch rib when the lifting frame is lifted to the height position of the upper end of the suspender; the automatic loading and unloading device can move on the lifting frame.

[0050] In the step (2), the lower anchoring structure comprises an I-shaped anchoring upper connecting body, an anchoring connecting rod and an I-shaped anchoring lower connecting body; the I-shaped anchoring upper connecting body is welded with the anchoring structure on the beam body, and an anchoring connecting structure is arranged on the upper surface, for connecting the lower end of the temporary suspender and the new suspender; four through-hole jacks are installed at the lower surface of the I-shaped anchoring upper connecting body, two of which are used for tensioning the temporary suspender, and the other two are used for tensioning the new suspender; the I-shaped anchoring upper connecting body and the I-shaped anchoring lower connecting body are connected into one body through the anchoring connecting rod, and the I-shaped anchoring lower connecting body is arranged at the lower part of the beam body.

[0051] In the step (3), the upper end of the temporary suspender is connected to the anchoring plate of the temporary anchoring seat of the arch rib, and the lower end of the temporary suspender is connected to the anchoring connecting structure of the lower anchoring structure; by monitoring the cable force of the original suspender, the constant load internal force of the original suspender is obtained, the internal force is gradually loaded and released, and the cable force of the original suspender is gradually transferred to the temporary suspender; and then the two through-hole jacks are used to tension the temporary suspender in stages, and the tensioning control is 0, 15%, 35%, 50%, 70% and 100% in turn.

[0052] In the step (4), the original suspender is cut off by electric welding cutting, and the removed original suspender is removed by a crane and placed in a designated area.

[0053] In the step (5), the lower end of the new suspender is connected to the corresponding anchoring connection structure of the I-shaped anchoring connector.

[0054] In the step (6), the new suspender is tensioned while the cable force of the temporary suspender is released in stages to realize the equivalent conversion of the cable force of the temporary suspender to the new suspender; after the new suspender is tensioned to the design value and the elevation is adjusted, the lower end of the new suspender is completely anchored and connected to the lower anchoring structure.

[0055] In addition, in order to further improve the technical effects of the present application, in this embodiment, the automatic loading and unloading device comprises a device body, a driving motor, universal wheels, a brake mechanism, a loading and unloading operating rod, an angle sensing device, and a server. The loading and unloading operating rod is provided with five articulated rotating arms, and six different types of loading and unloading tools, such as a straight screwdriver, a cross screwdriver, various wrenches, etc., are arranged on the last rotating arm. The type of bolt or screw used according to the different anchoring structures can be controlled and selected by the controller to select the appropriate loading and unloading tool for operation. A high-definition image acquisition unit is also arranged on the last rotating arm, which can acquire the on-site situation in real time during loading and unloading operation, realize the accuracy of loading and unloading operation, and improve the construction efficiency.

[0056] The driving motor and the angle sensing device are arranged on the device body, and the angle sensing device can realize accurate adjustment and alignment of the loading and unloading tool and the anchoring structure. The universal wheels are arranged at the lower part of the device body, and when the device body reaches the designated construction position, the automatic loading and unloading device is positioned by the brake mechanism to facilitate loading and unloading operation. The loading and unloading operating rod is arranged at the top of the device body, realizing the integration of the structure, and the articulated connection of the rotating arm is provided with a server to realize the position adjustment and folding degree of the rotating arm.

[0057] In order to realize automatic control, a controller is also arranged, which communicates with each corresponding structure to control its corresponding operation. Through automatic control, the functions of time saving, labor saving and high efficiency of the present application are realized, and the problems of low assembly accuracy and part failure in actual manual operation are solved.

[0058] The automatic loading and unloading device of the present application realizes accurate alignment during loading and unloading, and can realize the taking, placing, tightening and loosening, and taking down of the connecting bolt and other components between the corresponding suspender and the connected anchoring structure, facilitating real-time clear observation of the loading and unloading operation. The construction difficulty is reduced, the construction period is shortened, and the safety factor of high-altitude operation is improved; the later suspender replacement construction is more convenient and faster.

[0059] Embodiment 3

[0060] A method for replacing a suspender of a tied-arch bridge, comprising the following steps:

[0061] (1) Setting a temporary facility at the connection between the upper end of the original suspender and the arch rib; the temporary facility comprises a temporary anchoring seat of the arch rib and an automatic loading and unloading device arranged on a lifting frame, the temporary anchoring seat of the arch rib is installed on the arch rib and connected with the upper end of the temporary suspender through an anchoring plate;

[0062] (2) Setting a lower anchoring structure at the connection between the lower end of the original suspender and the beam body; the lower anchoring structure is fixedly connected with the anchoring structure of the lower end of the original suspender on the beam body and fixedly arranged on the beam body;

[0063] (3) Lifting the temporary suspender to make the original suspender in a stress-free state; connecting the upper end of the temporary suspender to the temporary anchoring seat of the arch rib through the automatic loading and unloading device, and then connecting the lower end of the temporary suspender to the lower anchoring structure, so that the temporary suspender is stressed;

[0064] (4) Removing the original suspender; removing the upper end of the original suspender by using the automatic loading and unloading device; and then cutting the original suspender at the connection between the lower end of the original suspender and the anchoring structure without damaging the anchoring structure of the lower end of the original suspender on the beam body;

[0065] (5) Installing a new suspender; lifting the new suspender and installing the upper end of the new suspender at the connection between the upper end of the original suspender and the arch rib by using the automatic loading and unloading device; and then connecting the lower end of the new suspender to the lower anchoring structure;

[0066] (6) Adjusting the new suspender; grading the new suspender according to the designed suspender tensioning force until the designed value is reached; and then completely anchoring the lower end of the new suspender to the lower anchoring structure to make it reach a normal use stress state;

[0067] (7) Completing the replacement of the suspender and removing the temporary suspender and the temporary facility.

[0068] In the step (1), a construction worker stands on the lifting frame, waits for the lifting frame to be lifted to the height position of the upper end of the suspender, and installs the temporary anchoring seat of the arch rib on the arch rib, which is arranged adjacent to the connection between the upper end of the original suspender and the arch rib; the automatic loading and unloading device is movable on the lifting frame.

[0069] In the step (2), the lower anchoring structure comprises an I-shaped anchoring upper connecting body, an anchoring connecting rod and an I-shaped anchoring lower connecting body, the I-shaped anchoring upper connecting body is welded with the anchoring structure on the beam body and has an anchoring connecting structure arranged on the upper surface for connecting the lower end of the temporary suspender and the new suspender; four through-hole jacks are installed at the lower surface of the I-shaped anchoring upper connecting body, two of which are used for tensioning the temporary suspender and the other two of which are used for tensioning the new suspender; the I-shaped anchoring upper connecting body and the I-shaped anchoring lower connecting body are connected into one body through the anchoring connecting rod, and the I-shaped anchoring lower connecting body is arranged on the lower part of the beam body.

[0070] In the step (3), the upper end of the temporary suspender is connected to the anchoring plate of the temporary anchoring seat of the arch rib, and the lower end of the temporary suspender is connected to the anchoring connecting structure of the lower anchoring structure; the cable force of the original suspender is monitored to obtain the constant load internal force of the original suspender, the internal force is gradually loaded and released, and the cable force of the original suspender is gradually transferred to the temporary suspender; then the temporary suspender is tensioned by two through-hole jacks, and the step-by-step tensioning control is 0, 15%, 35%, 50%, 70% and 100% in turn.

[0071] In the step (4), the original suspender is cut off by electric welding cutting, and the removed original suspender is removed by the crane and placed in a designated area.

[0072] In the step (5), the lower end of the new suspender is connected to the corresponding anchoring connecting structure of the I-shaped anchoring upper connecting body.

[0073] In the step (6), the new suspender is tensioned while the cable force of the temporary suspender is gradually released, so that the cable force of the temporary suspender is equivalent to the new suspender; after the new suspender is tensioned to the design value and the elevation adjustment is appropriate, the lower end of the new suspender is completely anchored and connected to the lower anchoring structure.

[0074] In addition, in order to further improve the technical effect of the present application, in the embodiment, the new suspender is prepared by the following steps:

[0075] a. preparing a wire rod, which contains the following components in weight ratio: Mn: 20-30, Cr: 3-5, C: 2-3, Cu: 1-2, Si: 0.5-0.8, Ni: 0.4-0.5, P: 0.03-0.04, S: 0.03-0.04;

[0076] b. the wire rod is placed in a heating furnace and heated at 950℃ for 30-30min, and then cooled at a cooling rate of 15-20℃ / min;

[0077] c. surface treatment of the wire rod;

[0078] d. the wire rod is subjected to 6 times of cold drawing treatment by a winch, the traction force of the winch is 30-35KN, and the speed of the winding drum is 10-12r / min;

[0079] e. galvanizing treatment, the zinc amount of galvanizing is 230-240g / m 2 , the temperature is 480-490℃;

[0080] f. After cooling, a corrosion protection layer is coated on the surface thereof; the corrosion protection layer comprises the following components in parts by weight: benzyl silicone resin 35, calcium silicate 25, water-based epoxy resin 20, rubber oil 20, ozokerite 15, toluene-diphenyl phosphate 8, pine tar 8, 1,1,3(2-methyl-4-hydroxy-5-tert-butylphenyl) butane 6;

[0081] g. Final surface treatment, and the process is completed.

[0082] The new suspender adopted by the present application has low cost and high strength, the tensile strength of single steel strand is increased to 2200MPa, the maximum force elongation is 6.2%, the single wire surface shrinkage is 31%, the axial fatigue test is applied with 390MPa periodic load, and the 230 million times do not break. The steel consumption can be greatly saved, the suspender quality can be effectively improved, the construction time can be shortened, and the engineering quality stability can be ensured. Moreover, the suspender has high corrosion resistance and good fatigue resistance, the corrosion protection layer used has good stability, strong adhesion, long corrosion resistance period and good flame retardation effect, can be used for a long time in a harsh environment, so that the suspender is not eroded by the external environment, and the service life can be greatly improved. The economic benefit and social benefit are remarkable.

[0083] The corrosion protection layer is verified by the humidity resistance test and the salt spray resistance test, and no corrosion phenomenon occurs in the whole process. The flame retardation level reaches V-2 level. The test results all exceed the performance indexes in JG / T 430-2014 “Anti-corrosion lubricating grease for unbounded prestressed tendon”.

[0084] As known from the above embodiment, the method of the present application can avoid damage to the tied arch bridge structure, improve the suspender stress condition, facilitate the replacement of the suspender in later period, has less influence on the traffic of the bridge during the replacement period, and has good construction adaptability, fast construction, high efficiency, convenient operation, safety and reliability, and good economy.

[0085] The method of the present application does not need to drill holes on the original structure of the tied arch bridge, avoids damage to the structure, facilitates the replacement construction of the suspender, and can improve the suspender stress condition during the construction process, and facilitate the replacement of the suspender in later period.

[0086] Most of the construction process of the present application is completed on the bridge deck, which avoids damage to the environment; the old suspender does not need to be taken out from the beam end, and the upper end of the suspender is disassembled by using automatic loading and unloading equipment, which reduces the construction difficulty, shortens the construction period, and improves the safety factor of high-altitude operation; the replacement construction of the suspender in later period is more convenient and faster.

[0087] The present application is suitable for replacing the suspender of a tied-arch bridge, the construction tool has simple structure and low total cost, continuous tensioning can be easily realized, and the difficulty of force conversion operation is reduced. The vehicle passing clearance above the bridge deck has no over-limit facilities, and the traffic passing on the bridge deck is not affected. The construction process is mature, the working condition is stable, the control index is clear, and the construction method has small risk. The arch rib does not need to be holed, the arch rib structure and appearance are protected. The old suspender is not taken out from the beam body, time and effort are saved, and the anchoring structure at the lower end of the old suspender is left in the beam body, so that the structural strength of the beam body is increased. The safety and controllability of suspender replacement are realized, the application technology is worth popularizing, and has wide application prospect.

[0088] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application without departing from the technical scheme of the present application still falls within the protection scope of the present application.

Claims

1. A method for replacing the hangers of a tied-arch bridge, characterized in that, Includes the following steps: (1) A temporary facility is set up at the connection between the upper end of the original boom and the arch rib; the temporary facility includes a temporary anchor seat for the arch rib and an automatic loading and unloading device set on the lifting frame. The temporary anchor seat for the arch rib is installed on the arch rib and connected to the upper end of the temporary boom through an anchor plate. (2) The lower anchor structure is fixedly connected to the anchoring structure at the lower end of the original hanger on the beam and fixedly installed on the beam; (3) The upper end of the temporary suspender is connected to the temporary anchor seat of the arch rib by automatic loading and unloading equipment, and the lower end of the temporary suspender is connected to the lower anchor structure, so that the temporary suspender is under stress and the original suspender is in a stress-free state. (4) Remove the upper end of the original hanger using automatic loading and unloading equipment; then cut the original hanger at the connection between the lower end of the original hanger and the anchoring structure, without damaging the anchoring structure of the lower end of the original hanger on the beam. The automatic loading and unloading equipment includes a main body, a controller, a drive motor, casters, a brake mechanism, a loading and unloading operating lever, an angle sensing device, and a servo; the loading and unloading operating lever is equipped with a hinged rotating arm, and the last section of the rotating arm is equipped with loading and unloading tools and a high-definition image acquisition unit, and a servo is installed at the hinged connection of the rotating arm; (5) Raise the new boom and use automatic loading and unloading equipment to install the upper end of the new boom at the connection between the upper end of the original boom and the arch rib; connect the lower end of the new boom to the lower anchor structure; the lower anchor structure includes an I-shaped upper and lower anchoring body and an anchoring connecting rod. The I-shaped upper anchoring body is welded to the anchoring structure on the beam. An anchoring connecting structure is set on the upper surface to connect the lower end of the temporary boom and the new boom; four through-hole jacks are installed on the lower surface; the I-shaped upper and lower anchoring bodies and the anchoring connecting rod are connected as one unit. The U-shaped anchorage lower connector is set at the lower part of the beam; New hanger preparation: a. Prepare wire rod containing the following weight ratios: Mn: 20-30, Cr: 3-5, C: 2-3, Cu: 1-2, Si: 0.5-0.8, Ni: 0.4-0.5, P: 0.03-0.04, S: 0.03-0.04; b. Place the wire rod in a heating furnace and heat at 950℃ for 30-30 minutes, then cool at a cooling rate of 15-20℃ / min; c. Surface treatment of the wire rod; d. Six cold-drawing processes of the wire rod using a winch, with a winch traction force of 30-35KN and a drum speed of 10-12 r / min; e. Galvanizing treatment, with a zinc coating of 230-240 g / m². 2 f. After cooling, coat its surface with an anti-corrosion layer; the anti-corrosion layer contains the following parts by weight: 35 parts benzyl silicone resin, 25 parts calcium silicate, 20 parts water-based epoxy resin, 20 parts rubber oil, 15 parts ceresin wax, 8 parts toluene-diphenyl phosphate, 8 parts rosin, and 6 parts 1,1,3(2-methyl-4-hydroxy-5-tert-butylphenyl)butane; g. Final surface treatment, and the product is obtained. (6) According to the designed tension of the new suspender, tension the new suspender in stages until the design value is reached; completely anchor the lower end of the new suspender to the lower anchor structure so that it reaches the normal service stress state; while tensioning the new suspender, release the cable force of the temporary suspender in stages; (7) Complete the replacement of the boom and dismantle the temporary boom and temporary facilities.

2. The method for replacing the hangers of a tied-arch bridge according to claim 1, characterized in that, In step (1), the construction workers stand on the lifting frame. When the lifting frame is raised to the height of the upper end of the boom, the temporary anchor seat of the arch rib is installed on the arch rib. The installation position is close to the connection between the upper end of the original boom and the arch rib. The automatic loading and unloading equipment can move on the lifting frame.

3. The method for replacing the hangers of a tied-arch bridge according to claim 2, characterized in that, In step (3), the upper end of the temporary suspender is connected to the anchor plate of the temporary anchor seat of the arch rib, and the lower end of the temporary suspender is connected to the anchor connection structure of the lower anchor structure; by monitoring the cable force of the original suspender, the constant load internal force of the original suspender is obtained, and the internal force is loaded and released step by step to gradually transfer the cable force of the original suspender to the temporary suspender; then, the temporary suspender is tensioned in stages by two through-hole jacks, and the stage tensioning is controlled in sequence as 0%, 15%, 35%, 50%, 70%, and 100%.

4. The method for replacing the hangers of a tied-arch bridge according to claim 3, characterized in that, In step (4), the original boom is cut by electric welding, and a crane is used to remove the original boom and place it in a designated area.

5. The method for replacing the hangers of a tied-arch bridge according to claim 4, characterized in that, In step (5), the lower end of the new auger is connected to the corresponding anchoring connection structure of the I-shaped anchoring upper connection body.

6. The method for replacing the hangers of a tied-arch bridge according to claim 5, characterized in that, In step (6), the cable force of the temporary suspender is converted into an equivalent force of the new suspender. After the new suspender is tensioned to the design value and the elevation is adjusted appropriately, the lower end of the new suspender is completely anchored to the lower anchor structure.