Construction method for unidirectional erection of reinforced concrete beams of large-span arch bridge

Abstract

The invention relates to the technical field of a construction method for erecting a reinforced concrete beam in a long-span arch bridge, in particular to a construction method for unidirectionally erecting a reinforced concrete beam in a long-span arch bridge, which comprises the following steps of: hoisting and conveying a first-span steel beam section to a corresponding erection position by using a bridge girder erection machine; arranging a water bag for testing to a first counterweight area on the arch ring so as to carry out arch ring stress testing; obtaining the average moving distance of the water bag for testing on the upper surface of the arch ring and judging the stress state of the arch ring; determining a weight balancing mode of the weight balancing water bag according to the stress state to balance the weight of the first weight balancing area, and obtaining the vibration strength of the weight balancing water bag on the first weight balancing area; determining the moving speed of the bridge girder erection machine based on the vibration intensity; and controlling the bridge girder erection machine to sequentially complete erection of the steel beam sections according to the moving speed, and releasing the counterweight of the first counterweight area to complete erection of the tail span steel beam sections. According to the one-way bridging construction method, it is guaranteed that the arch ring is evenly stressed by combining the water bag balance weight and the stress test.

Description

Technical Field

[0001] This invention relates to the technical field of construction methods for erecting steel-concrete beams for long-span arch bridges, and particularly to a construction method for erecting steel-concrete beams for long-span arch bridges in one direction. Background Technology

[0002] Because large-span arches generate unbalanced bending moments and deformations when subjected to concentrated loads from the superstructure, traditional large-span arch bridge construction often employed two bridge-erecting machines symmetrically to avoid exceeding stress and deformation limits in the arch, which could lead to safety accidents. However, during the construction of the steel-concrete composite beam bridge deck of the Yashiqing Bridge, simulation calculations and on-site measurements were used to study a construction method that eliminated excessive loads by employing counterweights. This method ensured that the arch stress and deformation still met requirements when constructed span by span by span using a single bridge-erecting machine, guaranteeing construction safety, reducing temporary works and equipment usage, protecting the environment, and lowering costs. Previous bridge-erecting methods, which used two bridge-erecting machines simultaneously, required coordination between the two machines, resulting in high construction difficulty, high costs, and the risk of unbalanced loads.

[0003] In the prior art, Chinese Patent Publication No. CN118029266A discloses a method for erecting steel beams of a steel truss bridge, including: installing a jacking system on a jacking auxiliary support; installing temporary supports on each truss on the assembly support, and assembling and installing guide beams and rear counterweights; installing a girder erecting crane on the guide beam; installing and jacking the first segment; cyclically hoisting subsequent segment units; gradually dismantling the guide beam after the auxiliary pier side brackets on the guide beam; synchronously and cyclically constructing the steel beams to complete the jacking and erection of the side span steel beams, and lowering the entire bridge beams to the design elevation; using the girder erecting crane to erect the main span steel beams in a unidirectional cantilever towards the mid-span, and gradually hanging and tensioning the cables; installing the closure section with the girder erecting crane to complete the steel beam closure, thus completing the steel beam erection. Therefore, it can be seen that the steel beam erection method of the steel truss bridge has the problem that the arch ring has not yet formed a stable structural system before the bridge is completed. The construction load and the vibration caused by the movement of the bridge erecting machine will cause stress and deformation in the arch ring, which will lead to unbalanced torque during the construction process and reduce the construction efficiency. Summary of the Invention

[0004] To address this, the present invention provides a construction method for unidirectional erection of steel-concrete beams for long-span arch bridges, which overcomes the problem in the prior art where, because the arch ring has not yet formed a stable structural system before the bridge is completed, the construction load and the vibration caused by the movement of the bridge erecting machine will cause stress and deformation in the arch ring, resulting in unbalanced moments during the construction process and a decrease in construction efficiency.

[0005] To achieve the above objectives, the present invention provides a method for constructing a steel-concrete composite beam for a long-span arch bridge in one direction, comprising the following steps:

[0006] The first span steel beam segment is hoisted and transported to the corresponding erection position using a bridge erecting machine. The first span steel beam segment includes two sets of first span steel beams, and each set of first span steel beams includes the first steel beam segment, the middle steel beam segment, and the tail steel beam segment.

[0007] A corresponding number of bridge deck panels are erected on the first span of the steel beam at the corresponding erection position, and wet joints and shear stud welding are performed on each bridge deck panel and its adjacent bridge deck panels, as well as steel beam connections are made.

[0008] Test water bags were arranged in a weight gradient on the first counterweight area of ​​the arch ring to conduct arch ring stress tests.

[0009] The average distance the test water bag moved on the upper surface of the arch was obtained;

[0010] The stress state of the arch ring is determined based on the average moving distance.

[0011] The counterweight method of the counterweight water bag is determined based on the stress state and the area of ​​stress action;

[0012] Continue to apply weight to the first weight area according to the aforementioned weighting method, and detect the effective movement distance of the water bag used for weighting in the first weight area;

[0013] The number of counterweight water bags to be arranged is determined based on the effective moving distance;

[0014] The counterweight water bags are arranged in the first counterweight area according to the specified number, and the vibration intensity of the counterweight water bags in the first counterweight area is obtained.

[0015] The moving speed of the bridge erecting machine is determined based on the vibration intensity.

[0016] The bridge erecting machine is controlled to erect the first span steel beam segment and the middle span steel beam segment sequentially according to the moving speed, and the counterweight in the first counterweight area is released to complete the erection of the tail span steel beam segment.

[0017] Furthermore, the method for obtaining the average travel distance includes:

[0018] After placing the test water bags in the first counterweight area, record the initial position of each test water bag on the arch.

[0019] Real-time monitoring of the positional changes of the test water bags in the first counterweight area, and acquisition of the movement distance of each test water bag in the first counterweight area;

[0020] The average distance traveled was calculated based on the distance traveled by all the water bags in the tests, where,

[0021] The formula for calculating the average moving distance is the ratio of the total moving distance of each test water bag during the stress test to the total number of test water bags.

[0022] The distance each test water bag moves during the stress test is the difference between the final position of the individual test water bag after the stress test ends and the initial position of the individual test water bag before the test begins.

[0023] Further, determining the stress state of the arch ring based on the average moving distance includes:

[0024] The average moving distance is compared with a preset first moving distance and a preset second moving distance, respectively;

[0025] If the average moving distance is greater than the preset first moving distance and less than or equal to the preset second moving distance, then the stress state of the arch ring is determined to be a first-level stress state.

[0026] If the average moving distance is greater than or equal to the preset second moving distance, then the stress state of the arch ring is determined to be a secondary stress state.

[0027] The stress in the first-level stress state is greater than the stress corresponding to the second-level stress state.

[0028] Furthermore, if the stress state is determined to be the secondary stress state, the number of water bags used in the test is reduced.

[0029] The number of water bags used in the test is positively correlated with the feed distance of the bridge erecting machine.

[0030] Furthermore, the method of determining the counterweight of the water bag based on the stress state and the area of ​​stress application includes:

[0031] If the stress application area is a first-order stress state, then the stress application area is obtained;

[0032] The aforementioned counterweight method is applied to the area where the stress occurs, wherein...

[0033] The stress is applied to the area on the upper surface of the arch corresponding to the first-level stress state.

[0034] Furthermore, the counterweight method involves first moving the counterweight area to an edge position away from the center of the bridge, and then restoring the counterweight water bag to its initial position when the bridge erecting machine has traveled a distance exceeding half the radial length of the arch.

[0035] Furthermore, the effective moving distance is the actual moving distance of the water bag used for counterweighting in the first counterweight area during the counterweighting process according to the counterweighting method.

[0036] The effective movement distance is calculated as the ratio of the sum of the movement distances of each counterweight water bag in the first counterweight area to the total number of counterweight water bags:

[0037] The distance each counterweight water bag moves in the first counterweight area is the difference between the final position of the individual counterweight water bag during the counterweighting process according to the counterweighting method and the initial position of the individual counterweight water bag before the counterweighting begins according to the counterweighting method.

[0038] Furthermore, determining the moving speed of the bridge erecting machine based on the vibration intensity includes:

[0039] If the vibration intensity of the bridge erecting machine on the first steel beam is greater than the preset vibration intensity, the weight of the water bag will be converted into lateral pressure between the water bags as counterweight, reducing the feed speed of the bridge erecting machine moving along the steel beam.

[0040] The moving speed of the bridge erecting machine on the steel beam is negatively correlated with the vibration intensity.

[0041] Furthermore, the wet joint and shear stud welding of each bridge deck with its adjacent bridge deck, as well as the steel beam connection, includes:

[0042] The reinforcing bars at the longitudinal wet joint of the bridge deck are welded to the reinforcing bars of the adjacent bridge deck. The welding method is double-sided welding or lap welding.

[0043] The reinforcing bars at the transverse wet joint of the bridge deck are welded to the reinforcing bars of the main beam of the steel beam and the adjacent bridge deck, respectively.

[0044] Shear studs are vertically welded to the shear groove of the main beam of the steel beam;

[0045] The steel longitudinal beam joints are designed with friction-type high-strength bolts at the joints between the web and the lower flange of the steel longitudinal beam, and with submerged arc butt welding at the joints between the upper flange of the steel longitudinal beam.

[0046] The steel crossbeam joints are connected by friction-type high-strength bolts at the joint between the web of the steel crossbeam and the stiffening steel plate of the main steel beam, and by submerged arc welding at the joint between the upper flange of the steel longitudinal beam and the upper and lower flanges of the steel crossbeam.

[0047] The steel beam segments are assembled by fixing the longitudinal and transverse steel beams with bolts.

[0048] The connection of steel beam segments involves completing the on-site submerged arc butt weld and high-strength bolt connection between the steel beam segments.

[0049] Furthermore, the removal of the counterweight to the first counterweight area includes reducing the number of counterweight water bags in the first counterweight area after the erection of the first span steel beam segment and the middle span steel beam segment is completed in sequence.

[0050] Compared with existing technologies, the advantages of this invention are as follows: This invention utilizes simulation calculations and on-site measurements to implement unidirectional counterweight construction, eliminating excessive loads. This construction method ensures that the arch stress and deformation still meet requirements when constructed span by span by span using a single bridge erecting machine. By employing a bridge erecting machine to unidirectionally erect steel beam segments and bridge decks, combined with the use of counterweights in testing water bags and stress testing, the uniformity of the arch stress is ensured, overcoming the problem of excessive local stress caused by concentrated loads in traditional construction. Furthermore, by dynamically determining the bridge erecting machine's moving speed based on the vibration intensity of the counterweight water bags, the problem of reduced counterweight effect caused by excessively fast machine movement leading to water bag displacement in the counterweight area is overcome. Finally, by gradually releasing the counterweight in the first and middle span steel beam segments during erection, the problem of sudden stress changes in the arch caused by the complete removal of counterweights is overcome, ensuring the stability and safety of the structural system transition.

[0051] Furthermore, this invention determines the stress state of the main arch ring by simulating the stress values ​​of the top and bottom plates. Because the curvature of the arch axis and the local tangent angle change when the arch ring deforms under stress, the test water bags placed on the surface of the arch ring are displaced under the influence of gravity. This displacement is positively correlated with the deformation of the arch ring and its internal stress. Therefore, the simulation results verify the rationality of the water bag counterweight scheme, design the arrangement position, quantity, and weight of the water bags, and adjust the arrangement position, quantity, and weight of the water bags according to the dynamic progress of the bridge erecting machine's feed to ensure the counterweight effect, optimize the construction process, and improve erection efficiency.

[0052] Furthermore, the present invention determines the stress state of the arch by obtaining the average moving distance of the test water bag, so that the stress change trend of the test water bag during the test can be digitally quantified.

[0053] Furthermore, this invention installs vibration sensors at the placement of the test water bags in the stress area of ​​the arch ring to monitor the vibration intensity generated during the movement of the bridge erecting machine in real time. Based on the vibration intensity, the feed speed of the bridge erecting machine along the steel beam is dynamically adjusted. When the vibration intensity exceeds the preset vibration intensity, the weight of the counterweight water bags will be converted into lateral pressure between the water bags, causing the water bags to slip. By reducing the feed speed of the bridge erecting machine, the input of vibration energy can be effectively reduced, ensuring that the water bags remain stable in the counterweight area, thereby guaranteeing the counterweight effect and construction safety.

[0054] Furthermore, by employing water-filled ballast, this invention ensures that the stress and deformation of the arch ring meet the requirements, avoids simultaneous construction on multiple work surfaces, and reduces the number of risk points for personnel and equipment operations.

[0055] Furthermore, the present invention improves the integrity and durability of the structure through wet joint and shear stud construction. The combination of wet joint and shear stud is used to connect the bridge deck and steel beams, thereby improving the integrity and durability of the bridge.

[0056] Furthermore, the present invention ensures the integrity of the structure and the optimization of its stress performance by connecting the steel longitudinal beams and steel transverse beams.

[0057] Furthermore, this invention, by gradually reducing the number of counterweight water bags in the first counterweight area according to the construction progress during the erection of the first span steel beam, the middle span steel beam, and the tail section steel beam, avoids stress mutation and structural damage caused by the sudden release of the counterweight load, and ensures that the alignment and internal forces of the completed bridge meet the design requirements. Attached Figure Description

[0058] Figure 1 This is a flowchart illustrating the construction process of a unidirectional steel beam erection method for a large-span arch bridge according to an embodiment of the present invention.

[0059] Figure 2 This is a flowchart illustrating the process of connecting adjacent bridge decks and steel beams in the construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to an embodiment of the present invention.

[0060] Figure 3 This is a schematic diagram of the starting position of the steel beam segment hoisting and conveying in the construction method of unidirectional erection of steel-concrete beams for large-span arch bridges according to an embodiment of the present invention;

[0061] Figure 4 This is a schematic diagram showing the end position of the steel beam segment hoisting and transportation in the construction method of unidirectional steel-concrete beam erection for a large-span arch bridge according to an embodiment of the present invention. Detailed Implementation

[0062] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0063] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0064] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0065] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, these are respectively a process flow diagram of the unidirectional erection of steel-concrete beams for a large-span arch bridge according to an embodiment of the present invention, a process flow diagram of the connection between adjacent bridge decks and steel beams, a schematic diagram of the starting position of the steel beam segment hoisting and transportation, and a schematic diagram of the ending position of the steel beam segment hoisting and transportation; the unidirectional erection of steel-concrete beams for a large-span arch bridge according to the present invention includes:

[0067] Step S1: Use a bridge erecting machine to hoist and transport the first span steel beam segment to the corresponding erection position. The first span steel beam segment includes two sets of first span steel beams. Each set of first span steel beams includes the first steel beam segment, the middle steel beam segment, and the tail steel beam segment.

[0068] Step S2: Install a corresponding number of bridge decks on the first span of the steel beam at the corresponding erection position, and perform wet joint and shear stud welding on each bridge deck and its adjacent bridge deck, as well as steel beam connection.

[0069] Step S3: Arrange the test water bags according to the weight gradient on the first counterweight area of ​​the arch ring to conduct the arch ring stress test;

[0070] Step S4: Obtain the average distance the test water bag moves on the upper surface of the arch;

[0071] Step S5: Determine the stress state of the arch ring based on the average moving distance;

[0072] Step S6: Determine the counterweight method of the counterweight water bag based on the stress state and the area of ​​stress action;

[0073] Step S7: Continue to apply weight to the first weight area according to the described weight method, and detect the effective movement distance of the water bag used for weight application in the first weight area.

[0074] Step S8: Determine the number of counterweight water bags to be arranged based on the effective moving distance;

[0075] Step S9: Arrange the counterweight water bags in the first counterweight area according to the specified arrangement quantity, and obtain the vibration intensity of the counterweight water bags in the first counterweight area.

[0076] Step S10: Determine the moving speed of the bridge erecting machine based on the vibration intensity;

[0077] Step S11: Control the bridge erecting machine to sequentially erect the first span steel beam segment and the middle span steel beam segment according to the moving speed, and release the counterweight on the first counterweight area to complete the erection of the tail span steel beam segment.

[0078] Specifically, the first span of steel beam is hoisted and transported to the corresponding erection position using a JQ200 walking bridge erecting machine, and the corresponding number of bridge panels are erected on the first span of steel beam at the corresponding erection position using the JQ200 walking bridge erecting machine.

[0079] Specifically, the hoisting and transporting process uses a beam transport flatcar and a crane.

[0080] Specifically, the corresponding erection location is the design coordinate point corresponding to the bridge centerline and the 2% cross slope of the large-span arch bridge.

[0081] Specifically, the length of the first span steel beam is 23.8m.

[0082] Specifically, the first steel beam is about 7.9m long and weighs about 12t; the middle steel beam is about 8.0m long and weighs about 12t; and the last steel beam is about 7.9m long and weighs about 12t.

[0083] Specifically, each bridge deck measures 608.5cm in length, 269.5cm in width, and 25cm in thickness, and each bridge deck weighs 10.2t.

[0084] As will be understood by those skilled in the art, the process of hoisting, transporting, and erecting bridge decks is a conventional technical method well known to them, and therefore the process of hoisting, transporting, and erecting bridge decks will not be described in detail here.

[0085] In implementation, this invention employs unidirectional counterweight construction through simulation calculations and on-site measurements, eliminating excessive loads. This construction method ensures that the arch stress and deformation still meet requirements when constructed span by span by span using a single bridge erecting machine. By using the bridge erecting machine to erect steel beam segments and bridge decks unidirectionally, combined with the counterweight setting of testing water bags and stress testing, the uniformity of the arch stress is ensured, overcoming the problem of excessive local stress caused by concentrated loads in traditional construction. By dynamically determining the bridge erecting machine's moving speed based on the vibration intensity of the counterweight water bags, the problem of the counterweight water bags shifting in the counterweight area due to excessive machine speed, thus reducing the counterweight effect, is overcome. By gradually releasing the counterweight in the first counterweight area during the erection of the first and middle span steel beam segments, the problem of sudden stress change in the arch caused by the complete removal of counterweights is overcome, ensuring the stability and safety of the structural system transition.

[0086] Specifically, the long-span arch bridge is 469.2m long. The horizontal plane of the long-span arch bridge is a straight section with a longitudinal slope of 2.2% and a transverse slope of 2% in one direction. The main arch ring of the long-span arch bridge adopts a catenary reinforced concrete box section with a clear span L0=200m, a clear rise f0=34m, a clear rise-to-span ratio f0 / L0=1 / 5.88, and an arch axis coefficient m=1.85.

[0087] Specifically, the arch box of the long-span arch bridge has a single-box double-cell cross-section, with a single box width of 8.0m and a box height of 3.8m. The arch foot section 0 is constructed using scaffolding and cast-in-place, while sections 1 to 16 are constructed using inverted triangular inclined climbing basket cantilever construction, and the mid-span closure section is constructed using hanging scaffolding.

[0088] Specifically, test water bags are arranged in a weight gradient from the arch foot to the middle of the span in the first counterweight area on the arch ring to conduct arch ring stress tests.

[0089] In practice, the weight is gradually increased. Under the condition that the weight of a single test water bag is constant at 2 tons, the longitudinal spacing of the water bags is shortened from 4m to 2m from the arch foot of the large-span arch bridge towards the mid-span of the large-span arch bridge. At the same time, the number of transverse arrangement rows is increased. In a specific embodiment, the number of transverse arrangement rows is increased from 2 rows to 4 rows, so that the total counterweight load per unit arch axis length of the large-span arch bridge presents a gradient distribution that increases from small to large.

[0090] Specifically, the method for obtaining the average movement distance includes:

[0091] After placing the test water bags in the first counterweight area, record the initial position of each test water bag on the arch.

[0092] Real-time monitoring of the positional changes of the test water bags in the first counterweight area, and acquisition of the movement distance of each test water bag in the first counterweight area;

[0093] The average distance traveled was calculated based on the distance traveled by all the water bags in the tests, where,

[0094] The formula for calculating the average moving distance is the ratio of the total moving distance of each test water bag during the stress test to the total number of test water bags.

[0095] The distance each test water bag moves during the stress test is the difference between the final position of the individual test water bag after the stress test ends and the initial position of the individual test water bag before the test begins.

[0096] Specifically, the stress test process lasted for 48 hours.

[0097] Specifically, the mass of a single test water bag is 2 tons.

[0098] In practice, the present invention determines the stress state of the arch by obtaining the average moving distance of the water bag, so that the stress change trend of the water bag during the test can be digitally quantified.

[0099] Specifically, determining the stress state of the arch ring based on the average moving distance includes:

[0100] The average moving distance is compared with a preset first moving distance and a preset second moving distance, respectively;

[0101] If the average moving distance is greater than the preset first moving distance and less than or equal to the preset second moving distance, then the stress state of the arch ring is determined to be a first-level stress state.

[0102] If the average moving distance is greater than or equal to the preset second moving distance, then the stress state of the arch ring is determined to be a secondary stress state.

[0103] The stress in the first-level stress state is greater than the stress corresponding to the second-level stress state.

[0104] In practice, this invention determines the stress state of the arch by obtaining the average moving distance of the test water bag, so that the stress change trend of the test water bag during the test can be digitally quantified.

[0105] Specifically, if the stress state is determined to be the secondary stress state, the number of test water bags is reduced, wherein the number of test water bags is positively correlated with the feed distance of the bridge erecting machine.

[0106] Optionally, the selectable ranges for the preset first moving distance and the preset second moving distance are respectively the elevation values ​​of each control section of the main arch ring [23.9mm, 40mm] and [42.5mm, 45mm].

[0107] Preferably, the first preset moving distance is 24 mm, and the second preset moving distance is 43 mm.

[0108] In practice, when the average moving distance is greater than or equal to the preset second moving distance within 4 mm, it is determined to be a level two stress state, and the number of test water bags is adjusted to 95% of the current number of test water bags. When the average moving distance is greater than or equal to the preset second moving distance and exceeds 4 mm, the number of test water bags is reduced by 1 for every 1 mm exceeding the preset second moving distance. In a specific embodiment, the current average moving distance is 49 mm, the current number of test water bags is 100, and the reduced number of test water bags is 100 × 95% - (2 mm / 1 mm) × 1 = 93.

[0109] Specifically, the method of determining the counterweight of the water bag based on the stress state and the area of ​​stress application includes:

[0110] If the stress application area is a first-order stress state, then the stress application area is obtained;

[0111] The aforementioned counterweight method is applied to the area where the stress occurs, wherein...

[0112] The stress is applied to the area on the upper surface of the arch corresponding to the first-level stress state.

[0113] Specifically, the counterweight method involves first moving the counterweight area to an edge position away from the center of the bridge, and then restoring the counterweight water bag to its initial position when the bridge erecting machine has traveled more than half the radial length of the arch.

[0114] Specifically, the counterweight area is moved by changing the position of the counterweight water bags on the arch.

[0115] In implementation, this invention determines the stress state of the main arch ring by simulating the stress values ​​of the top and bottom plates. When the arch ring is deformed under stress, the curvature of its arch axis and the local tangent angle change, causing the test water bags placed on the surface of the arch ring to displace under the influence of gravity. This displacement is positively correlated with the deformation of the arch ring and its internal stress. Thus, the rationality of the water bag counterweight scheme is verified through simulation calculation results, the placement, quantity, and weight of the water bags are designed, and the placement, quantity, and weight of the water bags are adjusted according to the dynamic progress of the bridge erecting machine's feed to ensure the counterweight effect, optimize the construction process, and improve the erection efficiency.

[0116] Specifically, the effective moving distance is the actual moving distance of the water bag used for counterweighting in the first counterweight area during the counterweighting process according to the counterweighting method.

[0117] The effective movement distance is calculated as the ratio of the sum of the movement distances of each counterweight water bag in the first counterweight area to the total number of counterweight water bags:

[0118] The distance each counterweight water bag moves in the first counterweight area is the difference between the final position of the individual counterweight water bag during the counterweighting process according to the counterweighting method and the initial position of the individual counterweight water bag before the counterweighting begins according to the counterweighting method.

[0119] Specifically, the counterweighting process lasts for 48 hours.

[0120] Specifically, determining the moving speed of the bridge erecting machine based on the vibration intensity includes:

[0121] If the vibration intensity of the bridge erecting machine on the first steel beam is greater than the preset vibration intensity, the weight of the water bag will be converted into lateral pressure between the water bags as counterweight, reducing the feed speed of the bridge erecting machine moving along the steel beam.

[0122] The moving speed of the bridge erecting machine on the steel beam is negatively correlated with the vibration intensity.

[0123] Specifically, the vibration intensity test method involves setting a vibration sensor at the test water bag placement location in the stress area of ​​the arch ring, and determining the vibration generated by the bridge erecting machine during the feeding process that begins to cause displacement of the test water bag as the preset vibration intensity.

[0124] Optionally, the preset vibration intensity can be selected within a range of [0.05m / ]. 0.2m / ].

[0125] Preferably, the preset vibration intensity in this embodiment is 0.12 m / s. .

[0126] Specifically, the position of each test water bag is obtained by fixing a prism target at the top center of each test water bag, so as to obtain the average moving distance and effective moving distance of the test water bag.

[0127] During implementation, when the vibration intensity exceeds the preset vibration intensity value by 0.02 m / s... When the vibration intensity is within the specified range, adjust the feed rate to 95% of the current feed rate. If the vibration intensity exceeds the preset vibration intensity value by more than 0.02 m / s... For every 0.01m / This reduces the feed rate by 0.1 m / min. In one specific embodiment, the current vibration intensity is 0.17 m / min. The current feed rate is 1.5 m / min. The reduced feed rate is 1.5 m / min × 95% - (0.03 m / min). / 0.01m / ) × 0.1 m / min = 1.125 m / min.

[0128] In practice, this invention uses vibration sensors placed at the test water bag location in the stress zone of the arch ring to monitor the vibration intensity generated during the bridge erecting machine's movement in real time. Based on this vibration intensity, the feed speed of the bridge erecting machine along the steel beam is dynamically adjusted. When the vibration intensity exceeds the preset vibration intensity, the weight of the test water bag is converted into lateral pressure between the water bags, causing the water bags to slip. By reducing the feed speed of the bridge erecting machine, the input of vibration energy can be effectively reduced, ensuring that the water bags remain stable in the counterweight area, thereby guaranteeing the counterweight effect and construction safety.

[0129] Specifically, the wet joints and shear stud welding, as well as the steel beam connections, include:

[0130] The reinforcing bars at the longitudinal wet joint of the bridge deck are welded to the reinforcing bars of the adjacent bridge deck. The welding method is double-sided welding or lap welding.

[0131] The reinforcing bars at the transverse wet joint of the bridge deck are welded to the reinforcing bars of the main beam of the steel beam and the adjacent bridge deck, respectively.

[0132] Shear studs are vertically welded to the shear groove of the main beam of the steel beam;

[0133] The steel longitudinal beam joints are designed with friction-type high-strength bolts at the joints between the web and the lower flange of the steel longitudinal beam, and with submerged arc butt welding at the joints between the upper flange of the steel longitudinal beam.

[0134] The steel crossbeam joints are connected by friction-type high-strength bolts at the joint between the web of the steel crossbeam and the stiffening steel plate of the main steel beam, and by submerged arc welding at the joint between the upper flange of the steel longitudinal beam and the upper and lower flanges of the steel crossbeam.

[0135] The steel beam segments are assembled by fixing the longitudinal and transverse steel beams with bolts.

[0136] The connection of steel beam segments involves completing the on-site submerged arc butt weld and high-strength bolt connection between the steel beam segments.

[0137] In practice, this invention improves the integrity and durability of the structure through wet joint and shear stud construction. The combination of wet joint and shear stud is used to connect the bridge deck and steel beams, improving the integrity and durability of the bridge. By connecting the steel longitudinal beams and steel transverse beams, the integrity and stress performance of the structure are optimized.

[0138] In practice, this invention ensures the integrity of the structure and optimizes its load-bearing performance by connecting the steel longitudinal beams and steel transverse beams.

[0139] Those skilled in the art will understand that, based on the influence of natural conditions such as temperature, humidity, wind force, and terrain in the bridge erection environment, as well as factors such as traffic and space constraints at the construction site on wet joints, shear studs, and welding construction, the selection of concrete, reinforcing steel, and welding wire can be adaptively adjusted according to the erection environment factors.

[0140] Specifically, removing the counterweight to the first counterweight area includes reducing the number of counterweight water bags in the first counterweight area after the erection of the first span steel beam segment and the middle span steel beam segment is completed in sequence.

[0141] Specifically, the number of water bags used for counterweighting in the first counterweight area is reduced as follows: During the unidirectional erection of the 469.2m long steel-concrete beam, after the first and middle span steel beam sections are all erected and the bridge deck connections are completed, the erection of the tail span and the removal of the counterweight are carried out simultaneously in the following order: First, when the bridge erecting machine is about to enter the tail span and the cantilever bending moment reaches its maximum, all 93 2-ton water bags in the first counterweight area are kept in place to maintain balance; then, after the first steel beam section of the tail span is hoisted into place and connected to the middle span, 15 water bags are symmetrically removed to accommodate the cantilever length. The bridge deck was then shortened; next, after the deck was laid and the wet joint concrete had initially set, 20 water bags were symmetrically removed to utilize the permanent structure that formed the rigidity to share the load; when the bridge erecting machine moved to the vicinity of the mid-span of the tail span, 22 more water bags were removed; after all the steel beam segments of the tail span had their high-strength bolts finally tightened to form a continuous system, 18 more water bags were removed; finally, after all the wet joint concrete of the tail span had completed its curing period and the bridge deck system had formed a complete steel-concrete composite structure, the remaining 18 water bags were removed all at once, thus completing the counterweight removal work of the first counterweight area.

[0142] In practice, this invention gradually reduces the number of counterweight water bags in the first counterweight area according to the construction progress during the erection of the first span steel beam, the middle span steel beam, and the tail section steel beam. This avoids stress mutation and structural damage caused by the sudden release of the counterweight load, and ensures that the alignment and internal forces of the completed bridge meet the design requirements.

[0143] Construction Process: A bridge erecting machine is used to hoist and transport the first span steel beam segment to its corresponding erection position. The first span steel beam segment consists of two sets of first span steel beams, each set consisting of a first segment steel beam, a middle segment steel beam, and a last segment steel beam. A corresponding number of bridge deck panels are erected on the first span steel beam segment. Wet joints and shear studs are welded to each bridge deck panel and its adjacent bridge deck panels. At the same time, the connection between the steel beams is completed. After the steel beam segment is assembled in place, the relevant welding and bolting operations are completed. Solid wire CO2 gas shielded welding is used for the root pass, and flux-cored wire CO2 gas shielded filling and cover passes are used. The longitudinal and transverse wet joints of the bridge deck panels are poured with C50 micro-expansion concrete. After the single-span bridge steel beams and precast bridge deck panels are installed, the wet joints and shear grooves are constructed from the opposite direction of erection. To ensure a tight contact between the top surface of the steel beam and the reinforced concrete bridge deck, a 40mm thick epoxy mortar layer is applied to the top surface of the steel beam. To ensure no leakage of concrete during the wet joint pouring of the bridge deck and to ensure a smooth and uniform epoxy mortar surface, a 40x40mm rubber strip is attached to each side of the top surface of the steel beam. The rubber strips are straight and tightly fitted at the joints. During epoxy mortar application, the space between the rubber strips is filled and smoothed. Test water bags are then arranged according to a weight gradient in the first counterweight area of ​​the arch ring for arch ring stress testing. During the stress test, the positional changes of the test water bags are monitored in real time, and the movement distance of each test water bag is recorded. The average movement distance of all test water bags is calculated to assess the stress state of the arch ring. The average movement distance is compared with a preset first and second movement distance to determine the stress state of the arch ring: if the average movement distance is greater than the first movement distance but less than or equal to the second movement distance, it is determined to be a first-level stress state; if the average movement distance is greater than or equal to the second movement distance, it is determined to be a second-level stress state. The stress state and stress application area are used to determine the counterweight method of the water bags. If the stress state is level two, the number of test water bags is reduced. According to the determined counterweight method, the first counterweight area is counterweighted, and the effective movement distance of the water bags in the first counterweight area is measured. Based on the effective movement distance, the number of water bags to be arranged is determined. The water bags are then arranged in the first counterweight area according to the determined number, and the vibration intensity of the water bags in the first counterweight area is obtained. Based on the vibration intensity, the moving speed of the bridge erecting machine is determined, and the bridge erecting machine is controlled to complete the erection of the first span and the middle span steel beam segment sequentially at the determined moving speed. After the middle span steel beam segment is erected, the counterweight in the first counterweight area is removed to prepare for the erection of the tail span steel beam segment. Finally, the tail span steel beam segment is erected.

[0144] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A construction method for unidirectional erection of steel-concrete beams for a long-span arch bridge, characterized in that, include: The first span steel beam segment is hoisted and transported to the corresponding erection position using a bridge erecting machine. The first span steel beam segment includes two sets of first span steel beams, and each set of first span steel beams includes the first steel beam segment, the middle steel beam segment, and the tail steel beam segment. A corresponding number of bridge deck panels are erected on the first span of the steel beam at the corresponding erection position, and wet joints and shear stud welding are performed on each bridge deck panel and its adjacent bridge deck panels, as well as steel beam connections are made. Test water bags were arranged in a weight gradient on the first counterweight area of ​​the arch ring to conduct arch ring stress tests. The average distance the test water bag moved on the upper surface of the arch was obtained; The stress state of the arch ring is determined based on the average moving distance. The counterweight method of the counterweight water bag is determined based on the stress state and the area of ​​stress action; Continue to apply weight to the first weight area according to the aforementioned weighting method, and detect the effective movement distance of the water bag used for weighting in the first weight area; The number of counterweight water bags to be arranged is determined based on the effective moving distance; The counterweight water bags are arranged in the first counterweight area according to the specified number, and the vibration intensity of the counterweight water bags in the first counterweight area is obtained. The moving speed of the bridge erecting machine is determined based on the vibration intensity. The bridge erecting machine is controlled to erect the first span steel beam segment and the middle span steel beam segment sequentially according to the moving speed, and the counterweight in the first counterweight area is released to complete the erection of the tail span steel beam segment.

2. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 1, characterized in that, The method for obtaining the average movement distance includes: After placing the test water bags in the first counterweight area, record the initial position of each test water bag on the arch. Real-time monitoring of the positional changes of the test water bags in the first counterweight area, and acquisition of the movement distance of each test water bag in the first counterweight area; The average distance traveled was calculated based on the distance traveled by all the water bags in the tests, where, The formula for calculating the average moving distance is the ratio of the total moving distance of each test water bag during the stress test to the total number of test water bags. The distance each test water bag moves during the stress test is the difference between the final position of the individual test water bag after the stress test ends and the initial position of the individual test water bag before the test begins.

3. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 2, characterized in that, Determining the stress state of the arch ring based on the average moving distance includes: The average moving distance is compared with a preset first moving distance and a preset second moving distance, respectively; If the average moving distance is greater than the preset first moving distance and less than or equal to the preset second moving distance, then the stress state of the arch ring is determined to be a first-level stress state. If the average moving distance is greater than or equal to the preset second moving distance, then the stress state of the arch ring is determined to be a secondary stress state. The stress in the first-level stress state is greater than the stress corresponding to the second-level stress state.

4. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 3, characterized in that, If the stress state is determined to be the secondary stress state, then the number of water bags used for testing should be reduced. The number of water bags used in the test is positively correlated with the feed distance of the bridge erecting machine.

5. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 4, characterized in that, The method for determining the counterweight of the water bag based on the stress state and the stress application area includes: If the stress application area is a first-order stress state, then the stress application area is obtained; The aforementioned counterweight method is applied to the area where the stress occurs, wherein... The stress is applied to the area on the upper surface of the arch corresponding to the first-level stress state.

6. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 5, characterized in that, The counterweight method involves first moving the counterweight area to an edge position away from the center of the bridge, and then restoring the counterweight water bag to its initial position when the bridge erecting machine has traveled more than half the radial length of the arch.

7. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 6, characterized in that, The effective moving distance is the actual moving distance of the water bag used for counterweighting in the first counterweight area during the counterweighting process according to the counterweighting method. The effective movement distance is calculated as the ratio of the sum of the movement distances of each counterweight water bag in the first counterweight area to the total number of counterweight water bags: The distance each counterweight water bag moves in the first counterweight area is the difference between the final position of the individual counterweight water bag during the counterweighting process according to the counterweighting method and the initial position of the individual counterweight water bag before the counterweighting begins according to the counterweighting method.

8. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 7, characterized in that, The process of determining the moving speed of the bridge erecting machine based on the vibration intensity includes: If the vibration intensity of the bridge erecting machine on the first steel beam is greater than the preset vibration intensity, the weight of the counterweight water bags will be converted into lateral pressure between the water bags, reducing the feed speed of the bridge erecting machine moving along the steel beam. The moving speed of the bridge erecting machine on the steel beam is negatively correlated with the vibration intensity.

9. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 8, characterized in that, The process of wet-jointing and shear stud welding of each bridge deck with its adjacent bridge deck, as well as the connection of steel beams, includes: The reinforcing bars at the longitudinal wet joint of the bridge deck are welded to the reinforcing bars of the adjacent bridge deck. The welding method is double-sided welding or lap welding. The reinforcing bars at the transverse wet joint of the bridge deck are welded to the reinforcing bars of the main beam of the steel beam and the adjacent bridge deck, respectively. Shear studs are vertically welded to the shear groove of the main beam of the steel beam; The steel longitudinal beam joints are designed with friction-type high-strength bolts at the joints between the web and the lower flange of the steel longitudinal beam, and with submerged arc butt welding at the joints between the upper flange of the steel longitudinal beam. The steel crossbeam joints are connected by friction-type high-strength bolts at the joint between the web of the steel crossbeam and the stiffening steel plate of the main steel beam, and by submerged arc welding at the joint between the upper flange of the steel longitudinal beam and the upper and lower flanges of the steel crossbeam. The steel beam segments are assembled by fixing the longitudinal and transverse steel beams with bolts. The connection of steel beam segments involves completing the on-site submerged arc butt weld and high-strength bolt connection between the steel beam segments.

10. The construction method for unidirectional erection of steel-concrete beams for long-span arch bridges according to claim 9, characterized in that, The removal of the counterweight to the first counterweight area includes reducing the number of counterweight water bags in the first counterweight area after the erection of the first span steel beam segment and the middle span steel beam segment is completed in sequence.

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