A method for closure of mid-span of cable-stayed bridge by single-side hoisting

Abstract

The present application relates to a method for closure of a cable-stayed bridge by unilateral hoisting in the middle span, which comprises the following steps: respectively arranging bridge cranes on the erected bridges on both sides of the closure; hoisting the beam section to be erected on the erected bridge by using the bridge crane, and tensioning the inclined cable for the beam section to be erected for the first time; moving the bridge crane on one of the two sides of the closure to the beam section to be erected on the corresponding side, and tensioning the inclined cable for the second time, so that the maximum cantilever end elevation of the beam section to be erected on this side is increased to the first design elevation, and the maximum cantilever end elevation of the beam section to be erected on the other side is reduced to the second design elevation; using the bridge crane moved to the beam section to be erected to hoist the steel structure of the closure section, and connecting the steel structure of the closure section with the two erected beam sections to be erected, and unhooking the bridge crane after the connection is completed. By adjusting the cable force of the inclined cable to change the maximum cantilever end elevation of the beam section to be erected, the linear shape of the closure after the final closure is guaranteed, and the construction quality is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of bridge construction, and in particular to a method for closure of a mid-span during single-side hoisting of a cable-stayed bridge. Background Art

[0002] At present, composite beam cable-stayed bridges have the characteristics of light weight and strong spanning capacity, and are increasingly widely used in bridge construction. The main bridge of the Aojiang Bridge on the double-track of the Zhejiang Yongtaiwen Expressway is a double-tower double-cable-plane composite beam cable-stayed bridge, a two-way six-lane expressway, and a highway-Ⅰ level. The main bridge tower adopts an H-type portal tower, with a total tower height of 102.40m and C50 concrete. The main beam adopts a composite beam of steel beam and concrete bridge deck, with a beam height of 3.3m and a width (including wind nozzle) of 38.3m. The concrete bridge deck adopts C60 concrete, and the thickness of the standard section is 26cm; the total weight of the standard composite beam section is 458.5t. The cable-stayed cable adopts high-strength parallel steel wire, and is arranged in a fan-shaped manner on the longitudinal plane. The distance between the cable-stayed cable and the center of the tower column is arranged at 2.0m. The basic cable distance of the cable-stayed cable on the main beam is 12m, and the cable-stayed cable area of ​​the side span is 7.1m; there are 96 cable-stayed cables in the whole bridge. A pair of vertical supports are set at the cable tower; wind-resistant supports are set horizontally to resist the lateral displacement of the main beam under wind load and earthquake load. A pair of vertical supports are set at the top of the auxiliary pier and the side pier. In addition to the vertical supports, the top of the auxiliary pier and the transition pier is also equipped with limit blocks horizontally.

[0003] In some related technologies, the Aojiang Bridge adopts a construction method in which the steel structure is manufactured in a steel structure factory, the bridge deck is prefabricated in a prefabrication yard at the bridge site, and the bridge deck is assembled into an integral composite beam during the cantilever assembly process. The side span and tower area beam sections are hoisted by floating crane using the bracket method, and the remaining beam sections are assembled by cantilever using a bridge deck crane. The original middle span closure plan adopts bilateral lifting closure, and the specific steps are as follows: ① The maximum cantilever state before closure, at which the elevation on both sides is H12; ② The steel structure of the closure section is lifted by the bridge deck crane, and the elevation on both sides is Hhl = H12-△Hhl; ③ Accurately match the closure mouth and temporarily connect; ④ Permanent welding connection, bridge deck crane unhooking; ⑤ System conversion; ⑥ Bridge deck installation; ⑦ Casting wet joints and maintenance; ⑧ Dismantling the crane to complete the closure; ⑨ Adjusting the cables of the entire bridge and paving the second phase. In the state of the maximum cantilever end before the closure of the middle span, the original design uses the bridge deck crane on both sides of the closure mouth to lift the middle span closure section; however, it has the following problems:

[0004] Due to the limitation of the space for the bridge crane, it is not possible to use the double-sided lifting method as originally planned, and only a single-sided bridge crane can be used for the closure. However, it is difficult to control the line shape of the bridge closure mouth with single-sided lifting, which affects the closure effect. Summary of the invention

[0005] The embodiment of the present application provides a method for closure of the mid-span of a cable-stayed bridge by single-sided lifting, so as to solve the problem in the related art that when the lifting space of the closure is limited, double-sided lifting cannot be adopted, and the line shape of the closure of the bridge caused by single-sided lifting is difficult to control.

[0006] In a first aspect, a method for closure of a mid-span of a cable-stayed bridge by single-side hoisting is provided, which comprises the following steps:

[0007] Bridge cranes are installed on the erected bridges on both sides of the joint;

[0008] The bridge crane is used to hoist the beam section to be erected onto the erected bridge, and the first stay cable is tensioned on the beam section to be erected;

[0009] Move the bridge crane on one of the two sides of the joint to the corresponding side of the beam section to be erected, and tension the stay cable for the second time, so that the maximum cantilever end elevation of the beam section to be erected on this side is increased to the first design elevation, and the maximum cantilever end elevation of the beam section to be erected on the other side is reduced to the second design elevation;

[0010] Use the bridge crane that moves to the beam section to be erected to lift the steel structure of the joint section, and connect the steel structure of the joint section with the two erected beam sections to be erected. After the connection is completed, the bridge crane releases the hook.

[0011] In some embodiments, the second design elevation is the maximum cantilever end elevation of a beam segment to be erected when using double-sided lifting, half of the weight of the steel structure of the joint segment and the bridge crane act on the beam segment to be erected;

[0012] The elevation difference between the first design elevation and the second design elevation is: the change in the maximum cantilever end elevation of a beam section to be erected when a single-sided crane is used and the total weight of the steel structure of the joint section and the bridge crane act on the beam section to be erected.

[0013] In some embodiments, after the first tensioning of the stay cable, before moving the bridge crane on one of the two sides of the joint to the corresponding beam section to be erected, the following steps are also included:

[0014] Using the bridge crane to hoist the bridge deck on the two beam sections to be erected;

[0015] Tie the reinforcement between wet joints;

[0016] Cast the transverse wet joints between the beam sections to be erected, as well as the longitudinal and transverse wet joints between the bridge decks, and maintain them until the set time.

[0017] In some embodiments, after the bridge crane releases the hook, the following steps are also included:

[0018] Carry out the third tensioning of the stay cables;

[0019] Using two of the bridge cranes or one bridge crane to hoist the remaining bridge deck;

[0020] Tie the reinforcement between wet joints;

[0021] Cast the transverse wet joints between the beam section to be erected and the steel structure of the joint section, as well as the longitudinal and transverse wet joints between the bridge decks, and maintain them until the set time.

[0022] In some embodiments, the target cable force for the third tensioning of the inclined cable is equal to the cable force when the double-sided lifting is used. This cable force is the cable force of the inclined cable when the bridge deck is laid after the steel structure of the joint section and the beam section to be erected are connected.

[0023] In some embodiments, before using two of the bridge cranes or one bridge crane to hoist the remaining bridge deck, the completed bridge alignment and mid-span alignment are compared with the theoretical design value, and the measured bridge cable force is compared with the theoretical completed bridge cable force;

[0024] If the error between the mid-span alignment of the completed bridge and the theoretical design value, as well as the error between the measured cable tension and the theoretical completed bridge cable tension are both within ±%~%, then the requirements of the specification are met; otherwise, they are not met.

[0025] In some embodiments, after the maintenance is completed, the bridge crane is dismantled, and then all the inclined cables are adjusted to carry out the second phase of paving the bridge deck.

[0026] In some embodiments, the set time is -day.

[0027] In some embodiments, the bridge deck crane is located on the cantilever end of the erected bridge near the closure.

[0028] In a second aspect, a cable-stayed bridge is provided, characterized in that it is erected by using a single-side hoisting mid-span joint closing method for a cable-stayed bridge.

[0029] The beneficial effects of the technical solution provided by this application include:

[0030] An embodiment of the present application provides a method for single-sided lifting and mid-span closure of a cable-stayed bridge. After the beam section to be erected near the steel structure of the closure section is erected, only one of the bridge cranes is moved to the beam section to be erected, and then the inclined cable is tensioned to increase the maximum cantilever end elevation of the beam section to be erected where the bridge crane is set to a first design elevation, and the maximum cantilever end elevation of the other beam section to be erected is reduced to a second design elevation; thereby, after the steel structure of the closure section is lifted by the bridge crane located on the beam section to be erected, the maximum cantilever end elevations of the two beam sections to be erected become equal. The above steps change the maximum cantilever end elevation of the beam section to be erected by adjusting the cable force of the inclined cable to ensure the line shape of the closure after the final closure, thereby ensuring the construction quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A schematic diagram of hoisting a beam section to be erected according to the single-side hoisting mid-span joint closure method provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of hoisting the steel structure of the closure section of the single-side hoisting mid-span closure method provided in an embodiment of the present application;

[0034] Figure 3 The △Z displacement change curve of the maximum cantilever state before the mid-span closure of each parameter provided in the embodiment of the present application;

[0035] Figure 4 The cable force increment change curve of the maximum cantilever state before the mid-span closure of each parameter provided in the embodiment of the present application;

[0036] Figure 5 This is a curve of concrete stress increment change in the maximum cantilever state before closure of each parameter provided in the embodiment of the present application.

[0037] In the figure: 1. Bridge crane; 2. Beam section to be erected; 3. Cable-stayed cable; 4. Steel structure of the joint section; 5. Erected bridge. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0039] At the maximum cantilever end before the middle span is closed, the original design used cranes on both sides of the closure to lift the middle span closure section. However, due to the limitation of the crane space, it is not possible to lift the closure section on both sides according to the original plan, and only a single crane can be used to lift the closure section. In order to ensure smooth closure and reduce its adverse effects on the line shape and cable force of the completed bridge, it is necessary to analyze the sensitivity factors affecting the line shape of the closure, in order to provide a corresponding construction closure control plan.

[0040] For the selection of influencing parameters:

[0041] The finite element software Midas Civil 2019 was used to establish the beam unit bar system model of the Aojiang Bridge. The boundary conditions were: temporary consolidation of the tower beam, and single hinged connection of the transition pier and auxiliary pier. Nine load parameters were selected for sensitivity analysis of the displacement increment in the △Z direction of the maximum cantilever state before the mid-span closure, the cable force increment of the inclined cable, and the main beam stress increment.

[0042] Design parameter error is one of the main factors causing bridge construction errors, and its analysis is the premise of bridge construction control. The design parameters of bridge structures mainly refer to the elements that can cause changes in the structural state. For cable-stayed bridges, the main design parameters include the following categories: structural geometry parameters, cross-sectional characteristic parameters, time-related parameters, load parameters, material property parameters, etc. Structural geometry parameters refer to the span, span ratio, tower height, etc. of the bridge structure. For bridge structures that are already under construction, the errors of these parameters are very small and can be ignored. Therefore, this paper mainly analyzes the linear shape, cable force and main beam stress of the maximum cantilever state before closure based on the load parameters, time-related parameters and material property parameters of the Aojiang Bridge.

[0043] The error of the beam weight weighing system is about 2%. The density of the concrete weight of the auxiliary pier and transition pier is generally within 2% according to the laboratory test error. The hydraulic control accuracy of the cable tensioning jack is generally 1% to 2%. In addition to the deadweight of the bridge crane, the temporary load of the bridge deck generally includes the deadweight of personnel, machinery and some materials. According to statistics, it generally accounts for about 2% of the deadweight of the bridge crane. Therefore, the sensitivity analysis error of the beam weight, weight, cable force and temporary load parameters of the bridge deck is 2%. Generally speaking, the elastic modulus of concrete is built in the specification. The proposed value is smaller than the actual value. The fluctuation range of the elastic modulus of the concrete of the bridge tower and the main beam is 2% to 3% through on-site measurement. Therefore, the average value of the elastic modulus of the concrete of the bridge tower and the main beam is 1000MPa as the error value. According to the inspection report of the cable manufacturer, the error of the elastic modulus of the cable is generally within 1%. The design age requirement for the prefabricated bridge deck of the composite beam cable-stayed bridge is not less than 180 days, and the Aojiang Bridge is generally 2 to 3 months longer than the design due to actual production requirements. Therefore, this paper takes 90 days to analyze the impact of the error. Based on the above analysis, it is concluded that Figure 3 , Figure 4 and Figure 5 , and analyze it.

[0044] The △Z displacement variation curves of the maximum cantilever state before the mid-span closure of each parameter are as follows Figure 3 As shown in the figure, the transverse coordinates are selected from the anchor point position of the cable beam end. For the maximum cantilever state before the middle span is closed, Figure 3 It can be seen that the cable force of the inclined cable and the weight of the beam segment hoisting have a great influence on the linear shape of the main beam; Figure 4It can be seen that temporary loads and auxiliary pier pressure have a greater impact on the cable tension of the inclined cable; the hoisting weight of the beam section and the tensioning cable force have a greater impact on the stress of the concrete main beam. For the maximum cantilever state before the middle span closure that we are concerned about, the two error parameters of the cable tension of the inclined cable and the hoisting weight of the beam section have a greater impact on the linear shape. The errors of the other seven parameters have a smaller impact on the linear shape and can be ignored.

[0045] Finally, we learned that the lifting weight of the beam section and the tension cable force are the two parameters that have the greatest impact on the main beam linear shape and stress in the maximum cantilever state before the middle span is closed. The auxiliary pier weight and the elastic modulus of the main tower concrete are the parameters that have a greater impact on the cable force. When the construction reaches the middle span closure, the auxiliary pier weight and the elastic modulus of the main tower concrete are constant, so their impact on the cable force can be ignored. Then the advantage of unilateral lifting is that when the lifting space of the closure is limited, the unilateral lifting process is more complicated, and the control conditions increase, especially the control of the cable force.

[0046] Through the parameter sensitivity analysis of the maximum cantilever state before closure, the results show that the lifting weight of the beam section and the tension cable force are the two most important factors affecting the linear shape of the main beam in the maximum cantilever state before the closure of the middle span. According to this analysis result, by adjusting the cable force of the inclined cable at the maximum cantilever end of the closure mouth, the difference between the elevation of the closure mouth on the Aojiang side and the Longgang side that bears the unilateral lifting is exactly equal to the downward displacement value caused by the weight of the closure section on the Aojiang side that bears the unilateral lifting. Based on this, a unilateral lifting construction plan is further proposed, that is, the embodiment of this application provides a method for unilateral lifting of the middle span of a cable-stayed bridge to solve the problem in the related technology that when the lifting space of the closure mouth is limited, bilateral lifting cannot be used, and the linear shape of the bridge closure mouth caused by unilateral lifting is difficult to control.

[0047] Please refer to Figure 1 and Figure 2 A method for closing the middle span of a cable-stayed bridge by unilateral hoisting comprises the following steps:

[0048] Bridge cranes 1 are respectively arranged on the erected bridges 5 on both sides of the joint; the bridge cranes 1 are located on the cantilever ends of the erected bridges 5 close to the joint.

[0049] The bridge crane 1 is used to hoist the beam section 2 to be erected onto the erected bridge 5, and the first tensioning of the inclined cable 3 is performed on the beam section 2 to be erected;

[0050] Move the bridge crane 1 on one of the two sides of the joint to the corresponding side of the beam section 2 to be erected, and tension the stay cable 3 for the second time, so that the maximum cantilever end elevation of the beam section 2 to be erected on this side is increased to the first design elevation, and the maximum cantilever end elevation of the beam section 2 to be erected on the other side is reduced to the second design elevation;

[0051] The bridge crane 1 is moved to the beam section 2 to be erected to lift the joint section steel structure 4, and the joint section steel structure 4 is connected to the two erected beam sections 2 to be erected. After the connection is completed, the bridge crane 1 is unhooked.

[0052] After the beam section 2 to be erected near the steel structure of the joint section (the bridge 5 has been erected) is erected, only one of the two bridge cranes 1 is moved to the corresponding side of the beam section 2 to be erected that has been erected, and then the inclined cable 3 is tensioned to increase the maximum cantilever end elevation of the beam section 2 to be erected where the bridge crane 1 is set to the first design elevation, and the maximum cantilever end elevation of the other beam section 2 to be erected is reduced to the second design elevation; thereby, after the steel structure of the joint section is hoisted by the bridge crane 1 located on the beam section 2 to be erected, the maximum cantilever end elevations of the two beam sections 2 to be erected become equal. The above steps change the maximum cantilever end elevation of the beam section 2 to be erected by adjusting the cable force of the inclined cable 3, and ensure the linear shape of the joint after the final joint is completed by unilateral hoisting to ensure the construction quality.

[0053] In some preferred embodiments, the second design elevation is the maximum cantilever end elevation of a beam segment 2 to be erected when using double-sided lifting, half of the weight of the joint section steel structure 4 and the bridge crane 1 act on a beam segment 2 to be erected;

[0054] The elevation difference between the first design elevation and the second design elevation is: when a single-sided crane is used and the total weight of the steel structure 4 of the joint section and the bridge crane 1 act on a beam section 2 to be erected, the change in the maximum cantilever end elevation of the beam section 2 to be erected.

[0055] In some preferred embodiments, after the first tensioning of the stay cable 3, before moving the bridge crane 1 on one of the two sides of the joint to the corresponding beam section 2 to be erected, the following steps are also included:

[0056] Using the bridge crane 1 to hoist the bridge deck on two beam sections 2 to be erected;

[0057] Tie the steel bars between the wet joints; cast the transverse wet joints between the beam sections 2 to be erected, as well as the longitudinal and transverse wet joints between the bridge decks, and maintain them until the set time.

[0058] In some preferred embodiments, after the bridge crane 1 releases the hook, the following steps are also included:

[0059] The cable-stayed cable 3 is tensioned for the third time; the remaining bridge deck is hoisted by two of the bridge cranes 1 or one bridge crane 1; the steel bars between the wet joints are tied; the transverse wet joints between the beam section 2 to be erected and the joint section steel structure 4, as well as the longitudinal and transverse wet joints between the bridge decks are cast, and maintained until the set time.

[0060] Among them, the target cable force of the inclined cable 3 for the third tensioning is equal to the cable force when the double-sided lifting is adopted. This cable force is the cable force of the inclined cable 3 when the bridge deck is laid after the joint section steel structure 4 and the beam section 2 to be erected are connected.

[0061] Furthermore, before using two bridge cranes 1 or one bridge crane 1 to hoist the remaining bridge deck, the mid-span alignment of the completed bridge is compared with the theoretical design value, and the measured bridge cable force is compared with the theoretical completed bridge cable force;

[0062] If the error between the mid-span alignment of the completed bridge and the theoretical design value, as well as the error between the measured bridge cable force and the theoretical completed bridge cable force are within ±2% to 3%, the specification requirements are met; otherwise, they are not met. After the maintenance is completed, the bridge deck crane 1 is dismantled, and then all the inclined cables 3 are adjusted, and the second phase of bridge deck paving is carried out.

[0063] The setting time mentioned above is 6-9 days, which is just a reference time. It can be adjusted accordingly, extended or shortened according to the situation of the wet joint.

[0064] The following is described with specific embodiments:

[0065] The deadweight of the steel structure of the closure section is 69.4t, and the deadweight of the concrete bridge deck is 131.3t. The construction steps of the single-side lifting closure scheme are as follows:

[0066] Step 1: The front fulcrums of the bridge cranes on the left and right sides of the closure section correspond to the occupied positions L-MBn-1 and R-MBn-1 (i.e., the bridge 5 has been erected), and the steel structures of the beam sections L-MBn and R-MBn (i.e., with the erected beam section 2) are lifted simultaneously on both sides of the closure section, and the steel structures of L-MBn and L-MBn-1, and R-MBn and R-MBn-1 are permanently connected;

[0067] Step 2: Tension the inclined cables L-MCn and R-MCn corresponding to the L-MBn and R-MBn beam sections on the left and right sides of the joint section for the first time.

[0068] Step 3: hoist and install the bridge decks of L-MBn and R-MBn on the left and right sides of the closure section respectively;

[0069] Step 4: Tie the steel bars between the wet joints, cast the transverse wet joints between the beam sections L-MBn and L-MBn-1, R-MBn and R-MBn-1 to precast the longitudinal and transverse wet joints of the bridge deck, and cure for 7 days;

[0070] Step 5: The bridge crane on the left side of the closure section moves forward to L-MBn, and the bridge crane on the right side remains in place;

[0071] Step 6: Tension the cables L-MCn and R-MCn for the second time, so that: the left L-MCn increases until the maximum cantilever end elevation of the L-MBn beam section is H12+△Hhl, and the right R-MCn decreases until the maximum cantilever end elevation of the R-MBn beam section is H12-△Hhl;

[0072] Step 7: The left bridge crane unilaterally lifts the MBH steel structure of the joint section. At this time, the maximum cantilever end elevation of the left L-MBn beam section is H12-△Hhl. The right bridge crane does not lift the joint section, the external load remains unchanged, and the maximum cantilever end elevation of the R-MBn beam section is still H12-△Hhl.

[0073] Step 8: The MBH steel structure of the joint section is precisely matched and permanently connected with the steel structures of the L-MBn beam section and the R-MBn beam section on the left and right sides, and the bridge deck crane is unhooked; the system conversion of the entire bridge is completed;

[0074] Step 9: Tension the stay cables L-MCn and R-MCn for the third time; the cable forces of L-MCn and R-MCn on the left and right sides before the bridge deck installation is completed after the system conversion is completed according to the original lifting scheme are used as the target cable forces for the third tensioning of the stay cables L-MCn and R-MCn.

[0075] Step 10: Hoisting and installation of the remaining bridge deck, casting of the remaining wet joints of the closure section, and curing for 7 days;

[0076] Step 11: Remove the bridge crane and complete the closure of the middle span by lifting on one side;

[0077] Step 12: Full adjustment of cables and second phase of paving.

[0078] Among them, H12 is the maximum cantilever end elevation before the joint is closed using the original lifting scheme; △Hhl is the displacement value of the maximum cantilever end drop when the mid-span joint section is lifted on both sides, that is, the maximum cantilever end drop displacement when the crane bears half the weight of the mid-span joint section.

[0079] The middle span of Aojiang Bridge was closed by single-sided lifting. The mid-span line shape of the completed bridge is consistent with the design value. The mid-span is 2 to 3 cm higher than the design value and gradually becomes 0 towards the tower area. The error between the measured cable force of the completed bridge and the theoretical cable force of the completed bridge is within ±2% to 3%, which meets the design and relevant specification requirements.

[0080] Since the lifting scheme for the middle span closure of Aojiang Bridge was changed from double-sided lifting at the closure mouth to single-sided lifting closure, in order to make the closure state of the middle span with the lifting and closure state of the bridge deck cranes on both sides of the closure mouth consistent with the original scheme, and reduce its adverse effects on the line shape and cable force of the completed bridge. This paper conducted a parameter sensitivity analysis on the maximum cantilever state before the closure. The results show that the lifting weight of the beam section and the tension cable force are the two most important factors affecting the line shape of the main beam in the maximum cantilever state before the closure of the middle span. According to the analysis results, by adjusting the cable force of the inclined cable at the maximum cantilever end of the closure mouth, the difference between the elevation of the closure mouth on the Aojiang side and the Longgang side that bears the single-sided lifting is exactly equal to the downward displacement value caused by the weight of the closure section on the Aojiang side that bears the single-sided lifting. Based on this, a single-sided lifting construction plan is further proposed. The cable force and line shape results of the completed bridge show that the control effect is good.

[0081] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0082] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0083] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for closing the middle span of a cable-stayed bridge by lifting it from one side, characterized in that: It includes the following steps: Bridge cranes (1) are respectively installed on the erected bridges (5) on both sides of the joint; The bridge crane (1) is used to hoist the beam section (2) to be erected onto the erected bridge (5), and the first stay cable (3) is tensioned on the beam section (2) to be erected; Moving the bridge crane (1) on one of the two sides of the joint to the corresponding side of the beam section (2) to be erected, and performing a second tensioning of the inclined cable (3) so that the maximum cantilever end elevation of the beam section (2) to be erected on the side is increased to the first design elevation, and the maximum cantilever end elevation of the beam section (2) to be erected on the other side is reduced to the second design elevation; Using a bridge crane (1) moved to the beam section (2) to be erected, the steel structure of the joint section (4) is lifted, and the steel structure of the joint section (4) is connected to the two beam sections (2) to be erected that have been erected, and the bridge crane (1) is unhooked after the connection is completed; The second design elevation is the maximum cantilever end elevation of a beam section (2) to be erected when half the weight of the joint section steel structure (4) and the bridge crane (1) act on the beam section (2) to be erected using double-sided lifting; The elevation difference between the first design elevation and the second design elevation is: when a single-sided crane is used, the total weight of the joint section steel structure (4) and the bridge crane (1) act on a beam section (2) to be erected, and the change in the maximum cantilever end elevation of the beam section (2) to be erected.

2. The method for closing the middle span of a cable-stayed bridge by lifting it from one side as claimed in claim 1, characterized in that: After the first tensioning of the stay cable (3), the following steps are also included before the bridge deck crane (1) on one of the two sides of the joint is moved to the corresponding beam section (2) to be erected: Using the bridge deck crane (1) to hoist the bridge deck on two beam sections (2) to be erected; Tie the reinforcement between wet joints; The transverse wet joints between the beam sections (2) to be erected and the longitudinal and transverse wet joints between the bridge decks are cast and cured to a set time.

3. The method for closing the middle span of a cable-stayed bridge by lifting it from one side as claimed in claim 1, characterized in that: After the bridge crane (1) releases the hook, the following steps are also included: Performing a third tensioning on the stay cable (3); Using two of the bridge deck cranes (1) or one bridge deck crane (1) to hoist the remaining bridge deck; Tie the reinforcement between wet joints; The transverse wet joints between the beam section to be erected (2) and the joint section steel structure (4), as well as the longitudinal and transverse wet joints between the bridge decks are cast and maintained until a set time.

4. The method for closure of the middle span of a cable-stayed bridge by single-side hoisting as claimed in claim 3, characterized in that: The target cable force of the inclined cable (3) for the third tensioning is equal to the cable force when the double-sided lifting is adopted. The cable force is the cable force of the inclined cable (3) when the bridge deck is laid after the joint section steel structure (4) and the beam section to be erected (2) are connected.

5. The method for closing the middle span of a cable-stayed bridge by lifting it from one side as claimed in claim 3, characterized in that: Before using two of the bridge deck cranes (1) or one bridge deck crane (1) to hoist the remaining bridge deck, compare the completed bridge alignment and mid-span alignment with the theoretical design value, as well as the measured bridge cable force with the theoretical completed bridge cable force; If the error between the mid-span alignment of the completed bridge and the theoretical design value, as well as the error between the measured cable tension and the theoretical completed bridge cable tension are both within ±2% to 3%, the requirements of the specification are met; otherwise, they are not met.

6. The method for closing the middle span of a cable-stayed bridge by lifting it from one side as claimed in claim 3, characterized in that: After the maintenance is completed, the bridge deck crane (1) is dismantled, and then all the inclined cables (3) are adjusted to carry out the second phase of paving the bridge deck.

7. The method for closing the middle span of a cable-stayed bridge by lifting it from one side as claimed in claim 2 or 3, characterized in that: The setting time is 6-9 days.

8. The method for closing the middle span of a cable-stayed bridge by lifting it from one side as claimed in claim 1, characterized in that: The bridge deck crane (1) is located on the cantilever end of the erected bridge (5) near the joint.

9. A cable-stayed bridge, characterized in that: It is erected by adopting the method for single-side lifting and mid-span closure of a cable-stayed bridge as described in any one of claims 1 to 8.

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