A method and system for closing a midspan of a cable-stayed bridge with a tower-beam-pier consolidation system

Abstract

The application relates to a closure method and a closure system of a cable-stayed bridge with a tower-beam-pier consolidation system, which comprises the following steps: installing cantilever segment steel beams on two main towers to form a closure gap, the main tower being a tower-beam-pier consolidation structure; installing a first jacking device on the two cantilever segment steel beams, and performing jacking test on the first jacking device to confirm the adjustment range of the closure gap; hoisting a closure segment steel beam directly below the closure gap; using the first jacking device to perform jacking to make the actual length of the closure gap greater than the length of the closure segment steel beam; lifting the closure segment steel beam to the closure gap, and connecting the closure segment steel beam with the two cantilever segment steel beams. According to the application, the first jacking device is installed on the cantilever segment steel beams on the two sides of the closure gap to apply active jacking force, so that the cantilever segment steel beams on the two sides of the main tower are forced to displace as a whole; even if the closure temperature is inconsistent with the design temperature, the design temperature difference elongation can be offset; the closure segment steel beam does not need to be cut, the construction period can be shortened, and the closure precision is improved.

Description

Technical Field

[0001] This application relates to the field of bridge closure construction technology, specifically to a method and system for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system. Background Technology

[0002] Bridge closure is one of the most critical, important, technically demanding, and difficult parts of bridge construction, and it is a crucial milestone in bridge development.

[0003] Currently, the closure of the main steel girder of a cable-stayed bridge generally adopts the method of cutting and matching closure sections. Specifically, the cutting and matching of closure sections involves first fabricating the closure section steel beams according to the design requirements at the beam fabrication yard, then determining the closure temperature based on the closure construction schedule, measuring the gap at the closure joint at that temperature, and cutting the closure section steel beams according to the measurement results and performing joint treatment. Four bridge deck cranes are then used to hoist the closure section steel beams into place and adjust them into position. After the closure temperature is reached and the closure section steel beams are in place, welding is carried out.

[0004] However, if the design temperature differs from the actual temperature, and the beam is cut and closed under these conditions, the beam length at the actual temperature will differ from the beam length at the original design temperature, leading to discrepancies between the internal forces of the main beam and the design. To avoid this, the cutting and hoisting of the closure section steel beam must be completed under specified temperature conditions. Therefore, the installation of the mid-span closure section of the cable-stayed bridge steel beam is constrained by a limited temperature range and construction time.

[0005] For railway bridges requiring high stiffness and bridges with seismic resistance requirements, cable-stayed bridges typically employ a tower-beam-pier integrated system. When the closure temperature is much higher than the design temperature, the steel beams experience thermal expansion and contraction, causing elongation due to temperature differences. This affects the closure gap, making mid-span closure technically challenging, resulting in long construction periods and low closure accuracy.

[0006] The present invention aims to provide a method and system for mid-span closure of a cable-stayed bridge where the closure temperature is inconsistent with the design temperature and the tower-beam-pier consolidation system is incompatible. Summary of the Invention

[0007] This application provides a method and system for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system, in order to solve the problems in related technologies where the temperature affects the closure gap, resulting in long construction period and low closure accuracy when the closure temperature is inconsistent with the design temperature.

[0008] The first aspect of this application provides a method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system, comprising the following steps:

[0009] Cantilever steel beams are installed on the two main towers respectively to form a closure joint. The main towers are a tower-beam-pier integrated structure.

[0010] The first jacking device is installed on the two cantilever steel beams, and a jacking test is conducted using the first jacking device to confirm the adjustment range of the closure joint.

[0011] The steel beam of the closure section is hoisted directly below the closure joint;

[0012] The first jacking device is used to perform jacking, so that the actual length of the closure joint is greater than the length of the closure segment steel beam;

[0013] Lift the closure section steel beam to the closure opening, and connect the closure section steel beam to the two cantilever section steel beams.

[0014] In some embodiments, installing the first alignment device on the two cantilever steel beam segments and using the first alignment device to conduct an alignment test to confirm the adjustment range of the closure joint includes:

[0015] The first jacking device is installed on the two cantilevered steel beams;

[0016] The closure section is continuously observed to obtain observation data, which includes at least the distance at the closure section at different time periods, the elevation and rotation angle of the two cantilever steel beams;

[0017] The closure time and closure temperature were determined based on the observed data.

[0018] The closure opening posture is adjusted based on the observed data;

[0019] A top-to-top test is conducted using the first top-to-top device, and the adjustment range of the closure joint is confirmed using a monitoring device.

[0020] In some embodiments, installing the first jacking device on the two cantilevered steel beam segments includes:

[0021] A first crossbeam is installed on the cantilever section steel beam on one side of the closure joint, and a second crossbeam and a first jack connected to the second crossbeam are installed on the cantilever section steel beam on the other side of the closure joint.

[0022] Install steel pipe piles to connect the first crossbeam and the first jack.

[0023] In some embodiments, installing the first jacking device on the two cantilevered steel beams further includes:

[0024] A second jacking device is installed on the top of one or more side towers to assist the first jacking device in synchronous jacking.

[0025] In some embodiments, the second jacking device includes a reaction frame mounted on the top of the pier and a second jack disposed on the reaction frame.

[0026] In some embodiments, the step of using the first jacking device to perform jacking, so that the actual length of the closure joint is greater than the length of the closure segment steel beam, includes:

[0027] Verify the observation data at the closure point;

[0028] The closure opening posture is adjusted based on the observed data;

[0029] Calculate the pushing amount of the first jacking device to offset the design thermal elongation;

[0030] The first jacking device is used to push the two cantilever steel beams in opposite directions to generate displacement, so that the actual length of the closure joint is greater than the length of the closure steel beam.

[0031] In some embodiments, after the cantilever section steel beam is installed, a stay cable is hung on the side of the main tower near the closure point to adjust the rotation angle of the cantilever section steel beam.

[0032] The second aspect of this application provides a mid-span closure system for a cable-stayed bridge with a tower-beam-pier integrated system, the mid-span closure system of which includes:

[0033] The first lifting device is used to lift the cantilever section steel beam onto the main tower to form a closure joint. The main tower is a tower-beam-pier integrated structure.

[0034] The first jacking device is installed on the two cantilever steel beams and is used to perform jacking to make the actual length of the closure joint greater than the length of the closure steel beam.

[0035] And a second lifting device, installed on the two cantilever steel beams, for lifting the closure section steel beam directly below the closure opening.

[0036] In some embodiments, the first jacking device includes: a first crossbeam disposed on a cantilever section steel beam on one side of the closure joint, a second crossbeam disposed on a cantilever section steel beam on the other side of the closure joint, a first jack connected to the second crossbeam, and a steel pipe pile connecting the first crossbeam and the first jack.

[0037] In some embodiments, the mid-span closure system of the cable-stayed bridge with the tower-beam-pier consolidation system further includes: a second pair of apex devices disposed on the pier tops of one or more side towers.

[0038] The beneficial effects of the technical solution provided in this application include:

[0039] This application applies an active jacking force by installing a first jacking device on the cantilever steel beams on both sides of the closure joint, which forces the cantilever steel beams on both main towers to shift as a whole, thus offsetting the design elongation due to temperature difference. Even if the design temperature is inconsistent with the actual temperature, it ensures that the lateral distance is sufficient for the closure steel beams to enter the closure joint. The closure steel beams do not need to be cut, which can shorten the construction period and improve the closure accuracy. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart illustrating the steps of a method for mid-span closure of a cable-stayed bridge using a tower-beam-pier integrated system, according to an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the overall structure of the mid-span closure system of the cable-stayed bridge in an embodiment of the present invention, which is a tower-beam-pier consolidation system.

[0043] Figure 3 for Figure 2 An enlarged view of part A in the mid-span closure system of the cable-stayed bridge, which is a tower-beam-pier integrated system.

[0044] Figure 4 This is a flowchart of step S2 in the method for mid-span closure of a cable-stayed bridge with a tower-beam-pier consolidation system according to an embodiment of the present invention.

[0045] Figure 5 This is a flowchart of step S21 in the method for mid-span closure of a cable-stayed bridge with a tower-beam-pier consolidation system according to an embodiment of the present invention.

[0046] Figure 6 This is a schematic diagram of the plan layout of the first apex device of the mid-span closure system of the cable-stayed bridge in the tower-beam-pier consolidation system of the present invention.

[0047] Figure 7 This is a flowchart of step S21 in the method for mid-span closure of a cable-stayed bridge with a tower-beam-pier consolidation system according to another embodiment of the present invention.

[0048] Figure 8 This is a schematic diagram of the plan layout of the second apex device of the mid-span closure system of the cable-stayed bridge in the tower-beam-pier consolidation system of the present invention.

[0049] Figure 9 This is a flowchart of step S4 in the method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system according to an embodiment of the present invention.

[0050] Figure 10 This is a side view of the first pair of apex devices of the mid-span closure system of the cable-stayed bridge in the tower-beam-pier consolidation system of the present invention.

[0051] Figure label:

[0052] 1. Main tower; 11. Cantilever steel beam; 12. Closure joint; 2. Side tower; 3. First jacking device; 31. First crossbeam; 32. Second crossbeam; 33. First jack; 34. Steel pipe pile; 4. Second lifting device; 5. Closure steel beam; 6. Second jacking device; 61. Reaction frame; 62. Second jack; 7. Locking device. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] This application provides a method and system for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system. It can solve the problems of temperature affecting the closure gap, long construction period due to the need for steel beam matching and cutting, and low closure accuracy in related technologies. It is particularly suitable for multi-tower cable-stayed bridges.

[0055] See Figure 1 As shown, the first aspect of this application provides a method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system, comprising the following steps:

[0056] Step S1: Using the first lifting device, install cantilever steel beams 11 on the two main towers 1 respectively to form a closure joint 12. The main tower 1 is a tower-beam-pier fixed structure.

[0057] Step S2: Install the first jacking device 3 on the two cantilever steel beams 1, and use the first jacking device 3 to conduct a jacking test to confirm the adjustment range of the closure joint 12.

[0058] Step S3: Use the second lifting device 4 to hoist the closure section steel beam 5 directly below the closure joint 12;

[0059] Step S4: Use the first jacking device 3 to perform jacking so that the actual length of the closure joint 12 is greater than the length of the closure section steel beam 5;

[0060] Step S5: Use the second lifting device 4 to lift the closure section steel beam 5 to the closure joint 12, and connect the closure section steel beam 5 with the two cantilever section steel beams 11.

[0061] In this embodiment, the first jacking device is installed on the cantilever steel beams on both sides of the closure joint to apply an active jacking force, which forces the cantilever steel beams on both main towers to shift as a whole, thus offsetting the design elongation due to temperature difference. Even if the design temperature is inconsistent with the actual temperature, it ensures that the lateral distance is sufficient for the closure steel beams to enter the closure joint. The closure steel beams do not need to be cut, which can shorten the construction period and improve the closure accuracy.

[0062] See Figure 2 As shown in the embodiment of this application, in the cable-stayed bridge, the main tower 1 is a tower-beam-pier integrated structure, and the side tower 2 is a tower-beam integrated structure with separate beam and pier. This system effectively improves the overall stiffness of the structure, the main beam, bridge tower and cable stays are subjected to better stress, and the adverse effects of temperature are reduced.

[0063] In some embodiments, in step S1, the first lifting device may be a girder crane or other lifting structures.

[0064] In some embodiments, in step S1, after the cantilever section steel beam 11 is installed, the first lifting device is removed; and a stay cable is hung on the side of the main tower 1 near the closure joint 12 to adjust the rotation angle of the cantilever section steel beam 11.

[0065] Removing the first lifting device and installing the stay cables will provide space for the installation of the second lifting device 4; moreover, installing the stay cables will facilitate the adjustment of the rotation angle and elevation of the cantilever steel beams 11 on both sides of the closure joint 12, and fine-tuning the length of the closure joint 12 to achieve high-precision mid-span closure.

[0066] See Figure 4 As shown, in some embodiments, step S2 includes:

[0067] Step S21: Install the first jacking device 3 on the two cantilever steel beams 11;

[0068] Step S22: Continuously observe the closure joint using a monitoring device to obtain observation data. The observation data shall include at least the spacing at the closure joint at different time periods, the elevation and rotation angle of the two cantilever steel beams 11.

[0069] Step S23: Determine the closure time and closure temperature based on the observation data;

[0070] Step S24: Based on the observation data, adjust the closure mouth posture using the adjustment device;

[0071] Step S25: Conduct a top-to-top test using the first top-to-top device 3, and use the monitoring device to confirm the adjustment range of the closure joint.

[0072] Since the main tower 1 in the cable-stayed bridge provided in this application embodiment is a tower-beam-pier integrated structure, in order to make the cantilever section steel beam 11 on the main tower 1 move as a whole, the first jacking device is installed on the two cantilever section steel beams 11, which can provide a large jacking force.

[0073] See Figure 5 and Figure 6 As shown, in some embodiments, step S21 includes:

[0074] Step S211: Install a first crossbeam 31 on the cantilever section steel beam 11 on one side of the closure joint 12, and install a second crossbeam 32 on the cantilever section steel beam 11 on the other side of the closure joint 12, and a first jack 33 connected to the second crossbeam 32.

[0075] Step S212: Install steel pipe piles 34 to connect the first crossbeam 31 with the first jack 33.

[0076] Under the action of the first jack 33, the steel pipe pile 34 provides the jacking force, and the two cantilever steel beams 11 move in opposite directions to generate displacement, thereby opening the closure joint 12, so that the actual length of the closure joint 12 is greater than the length of the closure section steel beam 5.

[0077] See Figure 7 and Figure 8 As shown, in some embodiments, step S21 further includes:

[0078] Step S213: Install a second jacking device 6 on the top of one or more side towers 2 to assist the first jacking device 3 in synchronous jacking.

[0079] In the cable-stayed bridge provided in this application embodiment, the side tower 2 is a structure with the tower and beam fixed together and the beam and pier separated. The second jacking device 6 is set on the top of one or more side towers 2 piers, which can assist the first jacking device 3 in multi-point jacking synchronous operation, effectively improve the stress on the cantilever section steel beam 11 of the main tower 1, reduce the frictional resistance of the support, avoid the phenomenon of steel beam deformation caused by excessive jacking force, and multi-point jacking can effectively reduce the force of a single jacking operation, making it easier to widen the gap of the closure joint 12, and improving the stress state of the closure joint steel beam.

[0080] In some embodiments, the second jacking device 6 includes a reaction frame 61 mounted on the top of the pier and a second jack 62 disposed on the reaction frame 61.

[0081] In some embodiments, during step S22, when continuously observing the closure joint using a monitoring device, continuous observation is conducted for 12-24 hours at a frequency of once every 2 hours to obtain observation data. The observation data includes at least the spacing at the closure joint at different time periods, the elevation and rotation angle of the two cantilever steel beams 11.

[0082] The monitoring device is a bridge health monitoring system established by applying modern information technologies such as sensing, Internet of Things, cloud computing, geographic information, and satellite navigation. It integrates load source monitoring, structural monitoring, data analysis and processing, alarm and evaluation, and provides strong technical support for the intelligent operation and maintenance of bridges by real-time and continuous monitoring of important parameters such as the bridge's environment, load input, and structural mechanical state indicators.

[0083] In some embodiments, in step S23, the closure time and closure temperature are determined by observing the change patterns at different time periods, which facilitates the closure construction and subsequent calculation of the adjustment amount of the closure joint 12, and ensures the erection space at the closure joint 12 during construction.

[0084] In some embodiments, in step S24, the closure posture is adjusted using an adjustment device based on the observation data. The main adjustment is to the elevation and rotation angle of the cantilever steel beams 11 on both sides. If there is still a deviation after adjustment, other auxiliary measures can be added for adjustment, such as adjusting the elevation and rotation angle by adjusting the counterweight (water bag) at the cantilever end, adjusting the cable tension of the stay cable, and adjusting the temporary loads such as the truck crane on the beam surface, so that the longitudinal slope of the cantilever steel beams 11 on both sides is close to the horizontal state.

[0085] In some embodiments, in step S25, a jacking experiment is conducted using the first jacking device 3, the adjustment range of the closure joint is confirmed using a monitoring device, and the relationship between the jacking force and displacement, as well as the deviation between theoretical data and actual data, are analyzed.

[0086] In some embodiments, in step S3, the second lifting device is specifically a closure hanger that lifts the closure section steel beam 5 by means of a jack. Its bottom pad partially overlaps with the reaction seat of the first jacking device 3. The closure hanger is installed synchronously when the first jacking device 3 is installed.

[0087] The matching manufacturing of the closure section steel beam 5 and the two cantilever section steel beams 11 refers to: measuring data between the measurement control points on the closure section steel beam 5 and the two cantilever section steel beams 11, accepting the manufacturing dimensions of the closure section steel beam 5, and collecting matching control data.

[0088] See Figure 9 and Figure 10 As shown, in some embodiments, step S4 includes:

[0089] Step S41: Use the monitoring device to verify the observation data at point 12 of the closure section;

[0090] Step S42: Based on the observation data, adjust the closure mouth posture using the adjustment device;

[0091] Step S43: Calculate the pushing amount of the first jacking device 3 using the monitoring device to offset the designed thermal elongation.

[0092] Step S44: Use the first jacking device 3 to perform jacking, move the two cantilever steel beams 11 in opposite directions to generate displacement, so that the actual length of the closure joint 12 is greater than the length of the closure steel beam 5.

[0093] In some embodiments, in step S41, the observation data at the closure joint 12 is reviewed using a monitoring device under the lifting condition of the steel beam 5 of the closure section.

[0094] In some embodiments, in step S42, the attitude of the closure joint is adjusted using an adjustment device based on new observation data. The main adjustment is to the elevation and rotation angle of the cantilever steel beams 11 on both sides. If there is still a deviation after adjustment, other auxiliary measures can be added for further adjustment.

[0095] In some embodiments, in step S43, the elongation of the cantilever section steel beam 11 is calculated based on the closure temperature and the design temperature difference, and the required gap is added to calculate the jacking amount of the first jacking device 3. After jacking, the closure opening posture is checked again to ensure that the closure section steel beam 5 can smoothly enter the closure opening 12, and displacement markings are made to release the jacking restriction.

[0096] The first jacking device 3 is only required to offset the designed thermal elongation, and it must be released before the end of the closure period. The stress caused by temperature changes during non-closure periods is borne by the locking device 7.

[0097] See Figure 6 and Figure 10 As shown, in some embodiments, the locking device 7 is used to withstand the stress caused by the temperature difference between day and night when the beam cannot be fully closed during the closure period. The locking device 7 consists of multiple precision-rolled threaded steel bars, including both internal beam locking and beam surface locking, and is installed during the matching process between the closure section steel beam 5 and the cantilever section steel beam 11.

[0098] In some embodiments, in step S5, when connecting the closure segment steel beam 5 to the two cantilever segment steel beams 11, they are closed simultaneously. If the conditions for simultaneous closure are not met, one end is temporarily fixed by the locking device 7, and the other end is welded first. After the welding is completed, the temporary fixed end is welded to complete the mid-span closure.

[0099] In some embodiments, in step S5, during closure, the splicing plate at the interface between the closure section steel beam 5 and the two cantilever section steel beams 11 is first installed, then the deviation is finely adjusted to achieve high-precision mid-span closure, and finally the high-strength bolt construction and steel beam welding are carried out.

[0100] When fine-tuning the deviation, the planar lateral deviation between the closure section steel beam 5 and the two cantilever section steel beams 11 can be adjusted using the beam surface reaction seat structure, and the limiting and fixing can be done; the vertical deviation between the closure section steel beam 5 and the two cantilever section steel beams 11 can be fine-tuned using water hose counterweight, cable stays, beam surface reaction seat structure, and closure hanger; the longitudinal distance between the closure section steel beam 5 and the two cantilever section steel beams 11 can be adjusted using the first jacking device 3, and the driving pin can be installed after complete locking.

[0101] In some embodiments, after the punching is completed, the jacking force is unloaded. First, a portion of the jacking force provided by the first jacking device 3 is unloaded, then all the jacking force provided by the second jacking device 6 is unloaded, and finally the remaining jacking force provided by the first jacking device 3 is unloaded. This staged unloading is safer and avoids sudden stress changes.

[0102] In some embodiments, after the high-strength bolt construction and steel beam welding are completed, the stay cables are then installed on the side of the main tower 1 away from the closure section 12. Then, the cables are adjusted and released throughout the bridge, causing the mid-span closure section to be locked.

[0103] The second aspect of this application provides a mid-span closure system for a cable-stayed bridge with a tower-beam-pier integrated structure. The mid-span closure system for a cable-stayed bridge with a tower-beam-pier integrated structure includes:

[0104] The first lifting device is used to lift the cantilever section steel beam 11 onto the main tower 1 to form the closure joint 12. The main tower 1 is a tower-beam-pier fixed structure.

[0105] The first jacking device 3 is installed on the two cantilever steel beams 11 and is used to perform jacking to make the actual length of the closure joint 12 greater than the length of the closure steel beam 5.

[0106] And a second lifting device 4, installed on the two cantilever steel beams 11, is used to lift the closure section steel beam 5 directly below the closure joint 12.

[0107] In some embodiments, the first jacking device 3 includes: a first crossbeam 31 disposed on a cantilever section steel beam 11 on one side of the closure joint 12, a second crossbeam 32 disposed on a cantilever section steel beam 11 on the other side of the closure joint 12, a first jack 33 connected to the second crossbeam 32, and a steel pipe pile 34 connecting the first crossbeam 31 and the first jack 33.

[0108] In some embodiments, the mid-span closure system of the cable-stayed bridge with tower-beam-pier consolidation system further includes: a second apex device 6 disposed on the pier top of one or more side towers 2.

[0109] The functions and structures of the above-mentioned devices have been described in detail in the method section, and will not be repeated here.

[0110] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0111] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0112] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system, characterized in that, Includes the following steps: Cantilever steel beams (11) are installed on the two main towers (1) respectively to form a closure joint (12). The main tower (1) is a tower-beam-pier solidified structure. Install the first jacking device (3) on the two cantilever steel beams (11) and use the first jacking device (3) to conduct a jacking test to confirm the adjustment range of the closure joint (12); The steel beam (5) of the closure section is hoisted directly below the closure joint (12); The first jacking device (3) is used to perform jacking so that the actual length of the closure joint (12) is greater than the length of the closure section steel beam (5); Lift the closure section steel beam (5) to the closure opening (12) and connect the closure section steel beam (5) with the two cantilever section steel beams (11); Among them, a second jacking device (6) is set on the top of one or more side towers (2) to assist the first jacking device (3) in synchronous jacking.

2. The method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system as described in claim 1, characterized in that, The installation of the first jacking device (3) on the two cantilever steel beams (11) and the use of the first jacking device (3) to conduct a jacking test to confirm the adjustment range of the closure joint (12) include: The first jacking device (3) is installed on the two cantilever steel beams (11); The closure section (12) is continuously observed to obtain observation data, which includes at least the distance between the closure section (12) at different time periods, the elevation and rotation angle of the two cantilever steel beams (11); The closure time and closure temperature were determined based on the observed data. The closure opening posture is adjusted based on the observed data; The adjustment range of the closure joint (12) is confirmed by conducting a top-to-top test using the first top-to-top device (3).

3. The method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system as described in claim 2, characterized in that, The installation of the first jacking device (3) on the two cantilever steel beams (11) includes: A first crossbeam (31) is installed on the cantilever section steel beam (11) on one side of the closure joint (12), and a second crossbeam (32) and a first jack (33) connected to the second crossbeam (32) are installed on the cantilever section steel beam (11) on the other side of the closure joint (12). Install steel pipe piles (34) to connect the first crossbeam (31) and the first jack (33).

4. The method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system as described in claim 1, characterized in that, The second jacking device (6) includes a reaction frame (61) installed on the top of the pier, and a second jack (62) installed on the reaction frame (61).

5. The method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system as described in claim 2, characterized in that, The step of using the first jacking device (3) to perform jacking so that the actual length of the closure joint (12) is greater than the length of the closure section steel beam (5) includes: Verify the observation data at the closure point (12); The closure opening posture is adjusted based on the observed data; Calculate the pushing amount of the first jacking device (3) to offset the design thermal elongation; Using the first jacking device (3) to perform jacking, the two cantilever steel beams (11) are moved in opposite directions to generate displacement, so that the actual length of the closure joint (12) is greater than the length of the closure steel beam (5).

6. The method for mid-span closure of a cable-stayed bridge with a tower-beam-pier integrated system as described in claim 1, characterized in that, After the cantilever section steel beam (11) is installed, a stay cable is hung on the side of the main tower (1) near the closure joint (12) to adjust the angle of the cantilever section steel beam (11).

7. A mid-span closure system for a cable-stayed bridge with a tower-beam-pier integrated structure, characterized in that, The cable-stayed bridge mid-span closure system of the tower-beam-pier consolidation system includes: The first lifting device is used to lift the cantilever section steel beam (11) onto the main tower (1) to form a closure joint (12), wherein the main tower (1) is a tower-beam-pier solidified structure; The first jacking device (3) is installed on the two cantilever steel beams (11) to perform jacking so that the actual length of the closure joint (12) is greater than the length of the closure steel beam (5); The second jacking device (6) is set on the top of one or more side towers (2) to assist the first jacking device (3) in synchronous jacking. And a second lifting device (4), installed on the two cantilever steel beams (11), for lifting the closure steel beam (5) directly below the closure opening (12).

8. The mid-span closure system of a cable-stayed bridge with a tower-beam-pier consolidation system as described in claim 7, characterized in that, The first jacking device (3) includes: a first crossbeam (31) set on a cantilever section steel beam (11) on one side of the closure joint (12), a second crossbeam (32) set on a cantilever section steel beam (11) on the other side of the closure joint (12), a first jack (33) connected to the second crossbeam (32), and a steel pipe pile (34) connecting the first crossbeam (31) and the first jack (33).

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