Method for setting the transverse camber of a bridge of the box girder type

Abstract

The application discloses a kind of transverse pre-camber setting method of longitudinal and cross beam structure bridge, it is related to steel bridge prefabricated assembly technology.This method first calculates the position of side longitudinal beam rotating shaft according to transverse pre-camber offset, solves the rotating angle of side longitudinal beam, uses CAD to add longitudinal pre-camber coordinate to complete middle and side longitudinal beam lofting, pre-lofting cross beam and checking its perpendicularity with longitudinal beam, if it is out of tolerance, then trim beam end 500mm away from bolt hole, then rotate side longitudinal beam around rotating shaft to form transverse pre-camber, respectively adapt size cross beam with middle longitudinal beam lower flange as reference, adjust splicing plate or beam end according to 10mm gap change, and plane flatness out of tolerance can be connected by micro folding splicing plate.The application fills the gap of transverse pre-camber complete construction, can actively offset lateral deformation of transverse load, has high digital lofting accuracy, and standardized grading adjustment considers construction efficiency and connection stress, avoids member distortion, base material damage, reduces manufacturing cost, shortens construction period, and is suitable for various longitudinal and cross beam system steel bridge.

Description

Technical Field

[0001] This invention relates to the field of steel structure bridge construction technology, specifically to a method for setting the lateral precamber of a longitudinal and transverse beam structure bridge. Background Technology

[0002] In bridge construction, setting the pre-camber is a crucial technology. Its purpose is to counteract the deflection of the bridge under load, ensuring the bridge's alignment and structural safety during use. Currently, in the field of bridge engineering, there is relatively mature theory and practical experience in setting longitudinal pre-camber. By rationally setting the longitudinal pre-camber, the vertical deformation of the bridge under loads such as vehicles and pedestrians can be effectively controlled. However, existing technologies have significant shortcomings in setting the transverse pre-camber of bridge structures. In practical engineering, bridge structures are subjected not only to vertical loads but also to lateral loads such as wind loads, centrifugal forces, and vehicle eccentric loads. These lateral loads can cause lateral deformation of the bridge. Traditional bridge structures, especially those with longitudinal and transverse beam systems, often neglect the impact of lateral deformation in their design, failing to incorporate lateral pre-camber, making it difficult to effectively control lateral deformation. When a bridge bears significant lateral loads during long-term use, it may cause unevenness on the bridge deck, affecting driving comfort; it may also lead to deviations from design requirements in lateral alignment and localized stress concentrations in the structure, ultimately impacting the bridge's service life and safety. For example, Chinese patent CN108978642A, entitled "A Method for Setting the Pre-camber of Steel Truss Beams," discloses a process for fitting the vertical pre-camber curve of steel truss beams. However, it only addresses the longitudinal pre-camber setting for vertical deflection and completely ignores lateral deformation control. Its technical solution only adjusts the length of the upper and lower chords of the truss to achieve vertical anti-camber, lacking the technical logic of rotating the side longitudinal beams and adapting the crossbeam interfaces. It is not suitable for steel bridges with multiple longitudinal beams and graded crossbeams in a longitudinal and transverse beam system. In addition, the journal "Key Technologies for Manufacturing and Installation of Highway Steel Structure Bridges" (Transportation World, Issue 18, 2021) discloses a construction process for laying out the alignment of steel longitudinal and transverse beam bridges and bolting and splicing. However, it only uses CAD to overlay the longitudinal pre-camber coordinates for laying out and does not propose an implementation path for lateral pre-camber. It relies solely on thickening the crossbeam section and adding lateral supports to reinforce the stiffness in response to lateral deformation. However, this passive stiffness reinforcement results in a large amount of material consumption, increased self-weight, poor economic efficiency, and lacks the core method of determining the lateral pre-arch by rotating the longitudinal beam, making it impossible to reserve space for lateral reverse deformation during the prefabrication stage.

[0003] Therefore, there is an urgent need for a new method for setting the lateral pre-camber of bridge structures, which can effectively set the lateral pre-camber without affecting the connection between the various parts of the structure, thus ensuring the stability of the bridge structure and the convenience of construction. Summary of the Invention

[0004] To address the shortcomings of existing technologies, such as the inability to actively set transverse pre-camber, difficulties in adapting transverse beam joints after longitudinal beam rotation, easy twisting of members, poor construction accuracy, and high cost, this invention provides a method for setting the transverse pre-camber of a longitudinal and transverse beam structure bridge.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned technical effects is as follows: A method for setting the lateral precamber of a longitudinal and transverse beam structure bridge, wherein the longitudinal and transverse beam structure includes a central longitudinal beam, side longitudinal beams, small transverse beams, large transverse beams, splicing plates connecting the longitudinal beams, and splicing plates connecting the longitudinal and transverse beams. The method for setting the lateral precamber includes the following steps: S1. Based on the bridge design requirements and load calculations, determine the required transverse precamber value and the rotation axis of the side longitudinal beams. S2. Based on the transverse precamber value determined in step S1 and the rotation axis of the side longitudinal beam, use trigonometric functions to calculate the rotation angle of the side longitudinal beam. S3. Laying out the middle longitudinal beam and the side longitudinal beam: Based on the design theoretical line shape and longitudinal precamber, lay out the line shape of the middle longitudinal beam and the side longitudinal beam to determine their theoretical positions; S4. Lay out the joint positions of the small and large horizontal beams. Determine their connection positions on the side longitudinal beams based on the coordinate values ​​of the key points where the small and large horizontal beams are located. Ensure the perpendicular relationship between the small and large horizontal beams and the side longitudinal beams. Then project the positions of the small and large horizontal beams on the side longitudinal beams onto the plane of the middle longitudinal beam to obtain the connection positions of the small and large horizontal beams on the middle longitudinal beam. S5. Based on the rotation angle of the side longitudinal beam determined in step S2, rotate the side longitudinal beam along its rotation axis until the predetermined angle is reached. S6. Laying out the main beam: After the side longitudinal beam is rotated, based on its rotated position, angle and the position of the main beam joint, redetermine the position of the main beam between the middle longitudinal beam and the side longitudinal beam, and adjust the dimensions of the connection between the main beam and the middle longitudinal beam and the side longitudinal beam according to the new position of the main beam. S7. Lofting of small crossbeams: After the side longitudinal beams are rotated, the position of the small crossbeams between the middle longitudinal beams and the side longitudinal beams is re-determined based on their rotated position, angle and the position of the small crossbeam joints. The dimensions of the small crossbeams connected to the middle longitudinal beams and the side longitudinal beams are adjusted according to the new position of the small crossbeams. S8. After all structural dimensions have been adjusted, the middle longitudinal beam, side longitudinal beam, small cross beam, and large cross beam are bolted together as a whole using the splicing plates between longitudinal beams and between longitudinal and transverse beams, thus completing the setting of the transverse pre-camber of the bridge structure.

[0006] Preferably, in the above-mentioned method for setting the transverse precamber of a longitudinal and transverse beam structure bridge, in step S1, based on the transverse precamber values ​​△1 and △2 provided by the designer, the position of the rotation axis of the side longitudinal beam is determined according to the formula H1=△1*H / (△1+△2). Where H1 is the vertical height between the rotation axis of the longitudinal beam to be solved and the lower surface of the upper flange of the longitudinal beam, H is the total vertical height of the longitudinal beam, △1 is the horizontal offset value of the key point of the center line of the longitudinal beam on the lower surface of the upper flange under the transverse pre-arch design relative to the original theoretical plumb line of the longitudinal beam, and △2 is the horizontal offset value of the key point of the center line of the longitudinal beam on the upper surface of the lower flange under the transverse pre-arch design relative to the original theoretical plumb line of the longitudinal beam.

[0007] Preferably, in the above-mentioned method for setting the transverse precamber of the longitudinal and transverse beam structure bridge, in step S2, the rotation angle of the side longitudinal beam is calculated based on the trigonometric function β = arcsin △1 / H1.

[0008] Preferably, the key points are the joint positions of the side longitudinal beams with the main crossbeam and the small crossbeam, as well as the joint positions of the two ends of the side longitudinal beams with the adjacent side longitudinal beams. Under the transverse pre-arch design, the side longitudinal beams are divided into sections according to the sections where each set of key points is located, and the rotation angle of the center line of the side longitudinal beam in each section is calculated independently until the rotation angle of the center line of the side longitudinal beam in each section where the key points are located is determined. When the rotation angles of the center lines of the side longitudinal beams in each section where the key points are located are not significantly different, the variance of the rotation angles at each location is taken as the rotation angle of the side longitudinal beam.

[0009] Preferably, in the above-mentioned method for setting the transverse precamber of the longitudinal and transverse beam structure bridge, when the variance of the rotation angle at each location is taken as the rotation angle of the side longitudinal beam, the difference of the rotation angle at each location is ≤1.5°.

[0010] Preferably, in the above-mentioned method for setting the transverse precamber of a longitudinal and transverse beam structure bridge, step S3, which involves laying out the alignment of the middle longitudinal beam and the side longitudinal beams based on the design theoretical alignment and the longitudinal precamber to determine their theoretical positions, includes the following steps: The positions of the main beam, the secondary beam, and the key points of the member interfaces are determined, and the theoretical lines provided by the design are converted into coordinate values ​​using CAD software. The precamber value determined by the design calculation is superimposed on the coordinate value of the theoretical alignment in the table; The coordinate values ​​after superimposing the pre-camber are converted into spatial lines in CAD software.

[0011] Preferably, in the above-mentioned method for setting the transverse precamber of the longitudinal and transverse beam structure bridge, after determining the connection positions of the small and large transverse beams on the middle longitudinal beam, the vertical relationship between the small and large transverse beams and the middle longitudinal beam is checked. If the deviation is within a negligible range of ≤0.2°, the small and large transverse beams are manufactured as normal members. If the vertical relationship exceeds the set deviation threshold, the angle between the end flange plate and the web plate of the small and large transverse beams is appropriately adjusted to ensure the vertical connection relationship between the small and large transverse beams and the middle longitudinal beam.

[0012] Preferably, in the above-mentioned method for setting the transverse precamber of the longitudinal and transverse beam structure bridge, the appropriate adjustment is as follows: at the end of the small transverse beam and the large transverse beam that are connected to the middle longitudinal beam, the angles of the upper and lower flange plates and the web plates are adjusted at a position more than 500mm away from the bolt hole range, so that the angles are consistent with the layout angle.

[0013] Preferably, in the above-mentioned method for setting the transverse precamber of a longitudinal and transverse beam structure bridge, the step of redetermining the position of the main transverse beam between the middle longitudinal beam and the side longitudinal beam based on its rotated position, angle, and the position of the main transverse beam joint after the side longitudinal beam has been rotated includes the following steps: The lower flange plate of the middle longitudinal beam end of the main crossbeam is flush with the lower flange plate of the middle longitudinal beam, and the gap is ensured. Using this point as a reference, rotate the main beam so that the lower flange plate of the side longitudinal beam is flush with the lower flange plate of the side longitudinal beam. The method of adjusting the dimensions of the connections between the main crossbeam and the middle longitudinal beam and the side longitudinal beam according to the new position of the main crossbeam includes the following steps: When the gap variation between the lower flange plate at the end of the main crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is ≤10mm, adjust the size of the splicing plate connecting the main crossbeam and the middle longitudinal beam and the side longitudinal beam. If the gap variation between the lower flange plate at the end of the main crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is greater than 10mm, adjust the end dimensions of the main crossbeam while ensuring the theoretical gap value.

[0014] Preferably, in the above-mentioned method for setting the transverse precamber of a longitudinal and transverse beam structure bridge, the step of redetermining the position of the small transverse beam between the middle longitudinal beam and the side longitudinal beam based on its rotated position, angle, and the position of the small transverse beam joint after the side longitudinal beam has been rotated includes the following steps: The lower flange plate of the middle longitudinal beam end of the small crossbeam is flush with the lower flange plate of the middle longitudinal beam, and the gap is ensured. Using this point as a reference, rotate the small crossbeam so that the lower flange plate of the side longitudinal beam is flush with the lower flange plate of the side longitudinal beam. The method of adjusting the dimensions of the connections between the small crossbeam and the middle longitudinal beam and the side longitudinal beam according to the new position of the small crossbeam includes the following steps: When the gap variation between the lower flange plate at the end of the small crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is ≤10mm, adjust the size of the splicing plate connecting the small crossbeam and the middle longitudinal beam and the side longitudinal beam. If the gap variation between the lower flange plate at the end of the small crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is greater than 10mm, adjust the end size of the small crossbeam while ensuring the theoretical gap value.

[0015] The beneficial effects of this invention are as follows: By setting a transverse pre-camber in the bridge structure, this invention can effectively counteract the deformation of the bridge under transverse loads, ensuring the transverse alignment and structural safety of the bridge, improving driving comfort and safety, extending the service life of the bridge, and optimizing the overall performance of the bridge. It also fills a gap in existing technology regarding the setting of transverse pre-camber in bridges. The process of setting the transverse pre-camber does not affect the connection between the main longitudinal beams, requiring no modification to the connection structure between the main longitudinal beams, thus ensuring the stability of the bridge structure. Simultaneously, it reduces construction difficulty and cost, and shortens the construction period. In addition, by adjusting the end dimensions of the crossbeam structure or the dimensions of the connecting parts between the longitudinal and transverse beams, it is possible to better adapt to the structural changes after the main longitudinal beam is rotated, ensure the tightness and stability of the connection between the crossbeam and the longitudinal beam, improve the overall performance of the bridge structure, and effectively solve the problems of difficulty in setting the transverse precamber of the bridge and the impact of structural adjustment on the connection in the existing technology. Attached Figure Description

[0016] Figure 1 This is a diagram showing the connection relationship of the longitudinal and transverse beam structures in this invention; Figure 2 This is a schematic diagram illustrating the determination of the rotation axis of the side longitudinal beam in this invention; Figure 3 This is a schematic diagram of the layout of the central longitudinal beam and the side longitudinal beam in this invention; Figure 4 This is a schematic diagram showing the layout of the crossbeam joint position in this invention; Figure 5 This is a schematic diagram showing the lateral pre-camber setting of the rotating side longitudinal beam in this invention; Figure 6 This is a schematic diagram of the layout and connection adjustment of the main beam structure in this invention; Figure 7 This is a schematic diagram of the layout and connection adjustment of the small crossbeam structure in this invention; Figure 8 This is a schematic diagram of the splicing plate connecting the longitudinal and transverse beams in this invention. Detailed Implementation

[0017] To provide a further understanding of the present invention, the invention will be further described below with reference to the accompanying drawings and specific embodiments: In the description of this invention, it should be noted that the terms "vertical," "upper," "lower," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0018] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0019] This invention proposes a method for setting the transverse precamber of a longitudinal and transverse beam bridge, such as... Figure 1 As shown, the longitudinal and transverse beam structure includes a central longitudinal beam 1, side longitudinal beams 2, small transverse beams 3, a large transverse beam, and connecting splicing plates between the longitudinal beams. The side longitudinal beams 2 are located on the left and right ends of the central longitudinal beam 1. Small transverse beams 3 are spaced between the side longitudinal beams 2 and the central longitudinal beam 1. Typically, the spacing between adjacent small transverse beams 3 is the same, and this space is used to install the large transverse beam. In the longitudinal direction, adjacent central longitudinal beams 1 and adjacent side longitudinal beams 2 are connected by connecting splicing plates between the longitudinal beams. Specifically, the connecting splicing plates between the longitudinal beams have an array of bolt holes. The sides of the central longitudinal beam 1 and side longitudinal beams 2, as well as the ends of the small transverse beams 3 and the large transverse beam, also have corresponding arrays of bolt holes. The structures are connected by high-strength bolts. The longitudinal beam members are I-shaped members, while the longitudinal beams at the supports and under the towers are variable-height I-box combined members. The small crossbeam members are I-shaped members, and the large crossbeam members are box-shaped members. All kinds of members are connected together by bolting to form a longitudinal and transverse beam structural system bridge.

[0020] In the transverse direction, the ends of the small crossbeam 3 and the large crossbeam are connected to the sides of the central longitudinal beam 1 and the side longitudinal beam 2 via connecting splicing plates between the longitudinal and transverse beams. The central longitudinal beam 1 and the two side longitudinal beams 2 are parallel in the longitudinal direction. Note that parallelism here refers to linear parallelism, not that their web surfaces are parallel. In fact, in the final longitudinal and transverse beam structure of this invention, the web surface of the central longitudinal beam 1 is typically vertical, while the web surfaces of the two side longitudinal beams 2 have a relative angle of inclination with the web surface of the central longitudinal beam 1. It should be noted that... Figure 1 The diagram shows a non-final arrangement of the longitudinal and transverse beam structure described in this invention, illustrating only the intermediate connection relationship of the longitudinal and transverse beam structure.

[0021] In an embodiment of the present invention, the method for setting the lateral pre-camber includes the following steps: S1. Based on the bridge design requirements and load calculations, determine the required transverse precamber value and the rotation axis of the side longitudinal beams. S2. Based on the transverse precamber value determined in step S1 and the rotation axis of the side longitudinal beam, use trigonometric functions to calculate the rotation angle of the side longitudinal beam. S3. Laying out the middle longitudinal beam and the side longitudinal beam: Based on the design theoretical line shape and longitudinal precamber, lay out the line shape of the middle longitudinal beam and the side longitudinal beam to determine their theoretical positions; S4. Lay out the joint positions of the small and large horizontal beams. Determine their connection positions on the side longitudinal beams based on the coordinate values ​​of the key points where the small and large horizontal beams are located. Ensure the perpendicular relationship between the small and large horizontal beams and the side longitudinal beams. Then project the positions of the small and large horizontal beams on the side longitudinal beams onto the plane of the middle longitudinal beam to obtain the connection positions of the small and large horizontal beams on the middle longitudinal beam. S5. Based on the rotation angle of the side longitudinal beam determined in step S2, rotate the side longitudinal beam along its rotation axis until the predetermined angle is reached. S6. Laying out the main beam: After the side longitudinal beam is rotated, based on its rotated position, angle and the position of the main beam joint, redetermine the position of the main beam between the middle longitudinal beam and the side longitudinal beam, and adjust the dimensions of the connection between the main beam and the middle longitudinal beam and the side longitudinal beam according to the new position of the main beam. S7. Lofting of small crossbeams: After the side longitudinal beams are rotated, the position of the small crossbeams between the middle longitudinal beams and the side longitudinal beams is re-determined based on their rotated position, angle and the position of the small crossbeam joints. The dimensions of the small crossbeams connected to the middle longitudinal beams and the side longitudinal beams are adjusted according to the new position of the small crossbeams. S8. After all structural dimensions have been adjusted, the middle longitudinal beam, side longitudinal beam, small cross beam, and large cross beam are bolted together as a whole using the splicing plates between longitudinal beams and between longitudinal and transverse beams, thus completing the setting of the transverse pre-camber of the bridge structure.

[0022] Specifically, in embodiments of the present invention, such as Figure 2 As shown, in step S1, based on the determined transverse precamber values ​​△1 and △2 provided by the designer, the position of the rotation axis of the side longitudinal beam is determined according to the formula H1=△1*H / (△1+△2); Where H1 is the vertical height between the rotation axis of the longitudinal beam to be solved and the lower surface of the upper flange of the longitudinal beam, H is the total vertical height of the longitudinal beam, △1 is the horizontal offset value of the key point of the center line of the longitudinal beam on the lower surface of the upper flange under the transverse pre-arch design relative to the original theoretical plumb line of the longitudinal beam, and △2 is the horizontal offset value of the key point of the center line of the longitudinal beam on the upper surface of the lower flange under the transverse pre-arch design relative to the original theoretical plumb line of the longitudinal beam. Figure 2 The black dot matrix on the left side of the mid-section plate indicates the array of bolt holes. (For example...) Figure 2 As shown, the original theoretical plumb line of the longitudinal beam is... Figure 2 The vertical line shown is generally determined by the designer based on the stress analysis results. That is, the values ​​of the lateral camber △1 and △2 are calculated by the designer based on the design requirements and load of the bridge. They are not analyzed in this invention. The problem to be solved by this invention is how to set the lateral camber on the longitudinal and transverse beam structures of the bridge.

[0023] Further, in step S2, as Figure 2 As shown, the rotation angle of the longitudinal beam is calculated using the trigonometric function β = arcsin△1 / H1.

[0024] In embodiments of the present invention, the key points are the joint positions of the side longitudinal beams with the main crossbeam and the small crossbeam, as well as the joint positions of the two ends of the side longitudinal beams with adjacent side longitudinal beams. Under the transverse pre-camber design, multiple key points are provided on the same side longitudinal beam, namely, the connection point A between the side longitudinal beam and the crossbeam and the end interface B of the side longitudinal beam. There are multiple A's and two B's. Two key points located on the same center line of the side longitudinal beam constitute a set of key points. The transverse pre-camber values ​​of each set of key points, i.e., △1 and △2, are provided by the designer.

[0025] Under the transverse pre-arch design, the side longitudinal beams are divided into sections according to the location of each set of key points. The rotation angle of the centerline of the side longitudinal beam in each section is calculated independently until the rotation angle of the centerline of the side longitudinal beam in each set of key points is determined. When the rotation angles of the centerlines of the side longitudinal beams in the sections of each set of key points are not significantly different, the variance of the rotation angles at each location is taken as the rotation angle of that side longitudinal beam. It should be noted that the division described here is not a physical division of the side longitudinal beam, but a theoretical design division; the centerline of the side longitudinal beam is the centerline along the height direction of the side longitudinal beam, that is, the line connecting the upper flange plate, web plate, and lower flange plate of the side longitudinal beam.

[0026] This invention aims to calculate the rotation angle of the centerline of the longitudinal beam at each set of key points under a transverse pre-camber design. The rotation angle at each set of key points may differ, with a difference ≤1.5°. After calculating and determining the rotation angle of the centerline at each set of key points, the variance of the rotation angles at each set of key points is used as the rotation angle of the entire longitudinal beam. That is, when determining the rotation angle of a longitudinal beam, the longitudinal beam is analyzed independently for each section containing a set of key points under the transverse pre-camber design (because the transverse pre-camber values ​​corresponding to each set of key points are not exactly the same), thereby determining the rotation angle of the centerline of the longitudinal beam in that section. After determining the rotation angle of the centerline of the longitudinal beam in each section containing a set of key points, the variance of the rotation angles at each location is taken as the rotation angle of the entire longitudinal beam.

[0027] When the rotation angles of the longitudinal beams at various points are not significantly different, the variance of the rotation angles at each point is taken as the rotation angle of the longitudinal beam. This ensures that the dimensions of the members meet the requirements and the connection relationships are correct, while also ensuring that the longitudinal beam members are non-torsional members, thus simplifying the manufacturing of the members and avoiding major adjustments. Typically, the rotation angles of the centerlines of the longitudinal beams at each set of key points are not significantly different, with an angle difference ≤1.5°, and most structures should meet this design requirement.

[0028] Furthermore, such as Figure 3 As shown, in step S3, the process of laying out the longitudinal beams and side beams according to the design theoretical alignment and longitudinal pre-camber to determine their theoretical positions includes the following steps: The positions of the main beam, the secondary beam, and the key points of the member interfaces are determined, and the theoretical lines provided by the design are converted into coordinate values ​​using CAD software. The precamber value determined by the design calculation is superimposed on the coordinate value of the theoretical alignment in the table; The coordinate values ​​after superimposing the pre-camber are converted into spatial lines in CAD software.

[0029] In the picture, Figure 3 (a) is a linear shape with a pre-camber value. Figure 3 (b) Theoretical linearity, Figure 3 (c) is the design line shape on which the precamber value is superimposed on the theoretical line shape.

[0030] Furthermore, in a preferred embodiment of the present invention, after determining the connection positions of the small crossbeam and the large crossbeam on the middle longitudinal beam, the vertical relationship between the small crossbeam and the large crossbeam and the middle longitudinal beam is checked. If the deviation is within a negligible range of ≤0.2°, the small crossbeam and the large crossbeam are manufactured as normal members. If the vertical relationship exceeds the set deviation threshold, the angle between the end flange plate and the web plate of the small crossbeam and the large crossbeam is appropriately adjusted to ensure the vertical connection relationship between the small crossbeam and the large crossbeam and the middle longitudinal beam.

[0031] Specifically, such as Figure 4 As shown, the appropriate adjustment is as follows: at the ends of the small crossbeam and the large crossbeam that are connected to the middle longitudinal beam, adjust the angles of the upper and lower flange plates and the web plates at a position more than 500mm away from the bolt hole, so that their angles are consistent with the layout angle α. Figure 4 (a) is a plan view of the end of the longitudinal beam in the connection of the crossbeam (small crossbeam, large crossbeam), wherein, at a position more than 500mm away from the bolt hole, the upper and lower flanges of the crossbeam are not perpendicular to the web plate and have a lofting angle α. Figure 4 (b) is Figure 4 (a) shows a cross-sectional view at “1-1”, which illustrates the lofting angle α between the upper flange, lower flange and web at that location. Figure 4 In (a), the black dot matrix on the left side of the web of the crossbeam represents the array of bolt holes. Step S4 of this invention ensures that the large and small crossbeams are manufactured as non-torsional members. After completing step S4, as... Figure 5 As shown, based on the rotation angle of the side longitudinal beam determined in step S2, the side longitudinal beam is rotated along its rotation axis until a predetermined angle is reached. In the figure, D indicates the horizontal distance between the rotation axis of the side longitudinal beam and the center line of the middle longitudinal beam, and D1 indicates the horizontal distance between the key point on the upper surface of the lower edge flange of the side longitudinal beam and the center line of the middle longitudinal beam. Where D1 < D, the side longitudinal beam is rotated through step S5 until a predetermined lateral pre-camber angle is reached.

[0032] Furthermore, in a preferred embodiment of the present invention, the step of re-determining the position of the main beam between the middle longitudinal beam and the side longitudinal beam based on its rotated position, angle, and the position of the main beam joint after the side longitudinal beam has been rotated includes the following steps: The lower flange plate of the middle longitudinal beam end of the main crossbeam is flush with the lower flange plate of the middle longitudinal beam, and the gap is ensured. Using this point as a reference, rotate the main beam so that the lower flange plate of the side longitudinal beam is flush with the lower flange plate of the side longitudinal beam. The method of adjusting the dimensions of the connections between the main crossbeam and the middle longitudinal beam and the side longitudinal beam according to the new position of the main crossbeam includes the following steps: When the gap variation between the lower flange plate at the end of the main crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is ≤10mm, adjust the size of the splicing plate connecting the main crossbeam and the middle longitudinal beam and the side longitudinal beam. Under this condition, it is more convenient to adjust the size of the splicing plate connecting the longitudinal beam and the side longitudinal beam. If the gap variation between the lower flange plate at the end of the main crossbeam and the lower flange plate of the middle longitudinal beam, and the lower flange of the side longitudinal beam is greater than 10mm, adjust the end dimensions of the main crossbeam while ensuring the theoretical gap value to ensure more reasonable stress distribution. After the connection dimensions are adjusted, if the flatness of the connection between the upper and lower flange plates exceeds the design threshold (>3mm), the splicing plate connecting the longitudinal and transverse beams at that location can be slightly bent to achieve a smooth connection between the members.

[0033] like Figure 6 The diagram shows the layout of the main beam structure and the adjustment of the connection points. The outer ends of the main beams 4 on both sides of the central longitudinal beam 1 are connected to the corresponding side longitudinal beams 2. The inner ends of the main beams 4 on both sides of the central longitudinal beam 1 are connected to the corresponding side of the central longitudinal beam 1. The gap or beam end size at each connection point is corrected according to the gap change value. The black dot matrix at each connection point indicates the bolt holes arranged in an array.

[0034] Furthermore, in a preferred embodiment of the present invention, the step of re-determining the position of the small crossbeam between the middle longitudinal beam and the side longitudinal beam based on its rotated position, angle, and the position of the small crossbeam joint after the side longitudinal beam has been rotated includes the following steps: The lower flange plate of the middle longitudinal beam end of the small crossbeam is flush with the lower flange plate of the middle longitudinal beam, and the gap is ensured. Using this point as a reference, rotate the small crossbeam so that the lower flange plate of the side longitudinal beam is flush with the lower flange plate of the side longitudinal beam. The method of adjusting the dimensions of the connections between the small crossbeam and the middle longitudinal beam and the side longitudinal beam according to the new position of the small crossbeam includes the following steps: When the gap variation between the lower flange plate at the end of the small crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is ≤10mm, adjust the size of the splicing plate connecting the small crossbeam and the middle longitudinal beam and the side longitudinal beam. Under this condition, it is more convenient to adjust the size of the splicing plate connecting the longitudinal beam and the side longitudinal beam. If the gap variation between the lower flange plate of the small crossbeam end and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is greater than 10mm, adjust the end dimensions of the small crossbeam while ensuring the theoretical gap value to ensure more reasonable stress distribution. After the connection dimensions are adjusted, if the flatness of the connection between the upper and lower flange plates exceeds the design threshold (>3mm), the splicing plate connecting the longitudinal and transverse beams at that location can be slightly bent to achieve a smooth connection between the members.

[0035] like Figure 7The diagram shows the layout and connection adjustments of the small crossbeam structure. The outer ends of the small crossbeams 5 on both sides of the central longitudinal beam 1 are connected to the corresponding side longitudinal beams 2. The inner ends of the small crossbeams 5 on both sides of the central longitudinal beam 1 are connected to the corresponding sides of the central longitudinal beam 1. The gaps or crossbeam end dimensions at each connection are adjusted according to the variation in gap values. The black dots at each connection represent the arrayed bolt holes. Figure 8 The diagram shows a schematic of the splicing plate 6 connecting the longitudinal and transverse beams. This splicing plate 6 has a bending line in the middle and bolt holes arranged in an array on both sides. It undergoes a micro-bending treatment based on the corresponding flatness difference. The splicing plate connecting the longitudinal and transverse beams... Figure 8 The structure of the splicing plate 6 connecting the longitudinal and transverse beams shown is the same.

[0036] This invention sets the transverse precamber of a bridge by rotating the longitudinal beam structure. While ensuring the connection between the side longitudinal beams and the middle longitudinal beams, the transverse beam structure is adjusted according to the structure after rotation, which effectively solves the problems of difficulty in setting the transverse precamber of bridges and the impact of structural adjustment on the connection in the prior art.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for setting the transverse precamber of a longitudinal and transverse beam structure bridge, wherein the longitudinal and transverse beam structure includes a central longitudinal beam, side longitudinal beams, small transverse beams, large transverse beams, connecting splice plates between longitudinal beams, and connecting splice plates between longitudinal and transverse beams, characterized in that, The method for setting the lateral pre-camber includes the following steps: S1. Based on the bridge design requirements and load calculations, determine the required transverse precamber value and the rotation axis of the side longitudinal beams. S2. Based on the transverse precamber value determined in step S1 and the rotation axis of the side longitudinal beam, use trigonometric functions to calculate the rotation angle of the side longitudinal beam. S3. Laying out the middle longitudinal beam and the side longitudinal beam: Based on the design theoretical line shape and longitudinal precamber, lay out the line shape of the middle longitudinal beam and the side longitudinal beam to determine their theoretical positions; S4. Lay out the joint positions of the small and large horizontal beams. Determine their connection positions on the side longitudinal beams based on the coordinate values ​​of the key points where the small and large horizontal beams are located. Ensure the perpendicular relationship between the small and large horizontal beams and the side longitudinal beams. Then project the positions of the small and large horizontal beams on the side longitudinal beams onto the plane of the middle longitudinal beam to obtain the connection positions of the small and large horizontal beams on the middle longitudinal beam. S5. Based on the rotation angle of the side longitudinal beam determined in step S2, rotate the side longitudinal beam along its rotation axis until the predetermined angle is reached. S6. Laying out the main beam: After the side longitudinal beam is rotated, based on its rotated position, angle and the position of the main beam joint, redetermine the position of the main beam between the middle longitudinal beam and the side longitudinal beam, and adjust the dimensions of the connection between the main beam and the middle longitudinal beam and the side longitudinal beam according to the new position of the main beam. S7. Lofting of small crossbeams: After the side longitudinal beams are rotated, the position of the small crossbeams between the middle longitudinal beams and the side longitudinal beams is re-determined based on their rotated position, angle and the position of the small crossbeam joints. The dimensions of the small crossbeams connected to the middle longitudinal beams and the side longitudinal beams are adjusted according to the new position of the small crossbeams. S8. After all structural dimensions have been adjusted, the middle longitudinal beam, side longitudinal beam, small cross beam, and large cross beam are bolted together as a whole using the splicing plates between longitudinal beams and between longitudinal and transverse beams, thus completing the setting of the transverse pre-camber of the bridge structure.

2. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1, characterized in that, In step S1, based on the determined transverse precamber values ​​△1 and △2 provided by the designer, the position of the rotation axis of the side longitudinal beam is determined according to the formula H1=△1*H / (△1+△2); Where H1 is the vertical height between the rotation axis of the longitudinal beam to be solved and the lower surface of the upper flange of the longitudinal beam, H is the total vertical height of the longitudinal beam, △1 is the horizontal offset value of the key point of the center line of the longitudinal beam on the lower surface of the upper flange under the transverse pre-arch design relative to the original theoretical plumb line of the longitudinal beam, and △2 is the horizontal offset value of the key point of the center line of the longitudinal beam on the upper surface of the lower flange under the transverse pre-arch design relative to the original theoretical plumb line of the longitudinal beam.

3. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1, characterized in that, In step S2, the rotation angle of the side longitudinal beam is calculated using the trigonometric function β = arcsin △1 / H1.

4. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1 or 2, characterized in that, The key points are the joint positions of the side longitudinal beams with the main and secondary horizontal beams, as well as the joint positions of the two ends of the side longitudinal beams with the adjacent side longitudinal beams. Under the transverse pre-arch design, the side longitudinal beams are divided into sections according to the area where each set of key points is located. The rotation angle of the center line of the side longitudinal beam in each section is calculated independently until the rotation angle of the center line of the side longitudinal beam in each section where the key points are located is determined. When the rotation angles of the center lines of the side longitudinal beams in each section where the key points are located are not significantly different, the variance of the rotation angles at each location is taken as the rotation angle of the side longitudinal beam.

5. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 4, characterized in that, When taking the variance of the rotation angle at each location as the rotation angle of the edge longitudinal beam, the difference in the rotation angle at each location should be ≤1.5°.

6. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1, characterized in that, In step S3, the process of laying out the alignment of the middle and side longitudinal beams based on the design theoretical alignment and longitudinal pre-camber to determine their theoretical positions includes the following steps: The positions of the main beam, the secondary beam, and the key points of the member interfaces are determined, and the theoretical lines provided by the design are converted into coordinate values ​​using CAD software. The precamber value determined by the design calculation is superimposed on the coordinate value of the theoretical alignment in the table; The coordinate values ​​after superimposing the pre-camber are converted into spatial lines in CAD software.

7. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1, characterized in that, After determining the connection positions of the small and large crossbeams on the middle longitudinal beam, check the vertical relationship between the small and large crossbeams and the middle longitudinal beam. If the deviation is within a negligible range of ≤0.2°, the small and large crossbeams are manufactured as normal members. If the vertical relationship exceeds the set deviation threshold, the angle between the end flanges and webs of the small and large crossbeams is appropriately adjusted to ensure the vertical connection between the small and large crossbeams and the middle longitudinal beam.

8. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 7, characterized in that, The appropriate adjustment is as follows: at the ends of the small crossbeam and the large crossbeam that are connected to the longitudinal beam, adjust the angles of the upper and lower flange plates and the web plates at a position more than 500mm away from the bolt holes, so that their angles are consistent with the layout angle.

9. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1, characterized in that, The process of re-determining the position of the main beam between the middle and side longitudinal beams based on the rotated position, angle, and position of the main beam joint after the side longitudinal beam has been rotated includes the following steps: The lower flange plate of the middle longitudinal beam end of the main crossbeam is flush with the lower flange plate of the middle longitudinal beam, and the gap is ensured. Using this point as a reference, rotate the main beam so that the lower flange plate of the side longitudinal beam is flush with the lower flange plate of the side longitudinal beam. The method of adjusting the dimensions of the connections between the main crossbeam and the middle longitudinal beam and the side longitudinal beam according to the new position of the main crossbeam includes the following steps: When the gap variation between the lower flange plate at the end of the main crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is ≤10mm, adjust the size of the splicing plate connecting the main crossbeam and the middle longitudinal beam and the side longitudinal beam. If the gap variation between the lower flange plate at the end of the main crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is greater than 10mm, adjust the end dimensions of the main crossbeam while ensuring the theoretical gap value.

10. The method for setting the transverse precamber of a longitudinal and transverse beam structure bridge according to claim 1, characterized in that, The process of re-determining the position of the small crossbeam between the middle longitudinal beam and the side longitudinal beam after the side longitudinal beam has been rotated, based on its rotated position, angle, and the position of the small crossbeam joint, includes the following steps: The lower flange plate of the middle longitudinal beam end of the small crossbeam is flush with the lower flange plate of the middle longitudinal beam, and the gap is ensured. Using this point as a reference, rotate the small crossbeam so that the lower flange plate of the side longitudinal beam is flush with the lower flange plate of the side longitudinal beam. The method of adjusting the dimensions of the connections between the small crossbeam and the middle longitudinal beam and the side longitudinal beam according to the new position of the small crossbeam includes the following steps: When the gap variation between the lower flange plate at the end of the small crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is ≤10mm, adjust the size of the splicing plate connecting the small crossbeam and the middle longitudinal beam and the side longitudinal beam. If the gap variation between the lower flange plate at the end of the small crossbeam and the lower flange plate of the middle longitudinal beam and the lower flange of the side longitudinal beam is greater than 10mm, adjust the end size of the small crossbeam while ensuring the theoretical gap value.

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