Construction method to improve the installation positioning accuracy of steel box beam

Abstract

The present invention relates to the technical field of bridge construction, and in particular to a construction method for improving the installation and positioning accuracy of steel box girders. First, a bracket hierarchical installation method is adopted, and a site that does not affect the operation of a crawler crane is selected. Steel box girder brackets for hoisting steel box girders are installed horizontally in groups of two, and then a distribution beam is fixed above the steel box girder bracket; the steel box girder is hoisted onto the distribution beam by a double crawler crane, and then the position of the steel box girder is measured and fine-tuned by a six-point positioning measurement method; after the installation and positioning of the steel box girder is completed, the crawler crane withdraws and prepares to install the next segment of the steel box girder bracket; the above steps are repeated to complete the hoisting of the steel box girder, and finally a temporary access road is used as a hoisting site to hoist the remaining steel box girders, and the temporary access road is a non-construction area outside the preset area of ​​the steel box girder bracket. This method can greatly improve the installation and positioning work efficiency and positioning accuracy of the steel box girder, and ensure the stability of the entire construction process.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a construction method for improving the installation and positioning accuracy of a steel box girder. Background Art

[0002] During the construction of large steel bridges, temporary supports are usually erected in the construction area of ​​the steel bridge as a temporary support system for the steel box girder. After all temporary support systems are erected, a large-tonnage crawler crane is used to install the steel box girder to the top of the support with a single-machine lifting method. A distribution beam is welded on the top of the support, and a steel pipe hard support supporting the steel box girder is welded on the distribution beam. The contact part between the steel pipe hard support and the steel box girder is processed by flame cutting. Then, the six-point positioning measurement method is used to measure the x, y, and z values ​​of the spatial coordinates of the four corner reference points of the top wing plate of the steel box girder, a total of 12 measurement values. The crawler crane, jack, hand winch and other auxiliary tools are used to adjust the steel box girder to the coordinate value required by the design according to the actual measured values ​​to achieve the positioning of the steel box girder. However, due to the limited construction site, there is no suitable place to place the steel box girder on site. The position between the steel box girder brackets limits the range of activities of the crawler crane, the occupied space and the rotation radius of the crane boom, resulting in the steel box girder not being able to accurately reach the installation position required by the design during hoisting. The steel pipe hard support welded on the top of the distribution beam is not in complete contact with the steel box girder, which requires high technical skills from the crawler crane driver, and the operation is also difficult during the hoisting process. The positioning accuracy of the steel box girder is low. It is difficult to adjust the spatial coordinates of each reference point to the range allowed by the specification with a large-tonnage crawler crane at the same time during the fine-tuning process, which also has a great impact on the threading of high-strength bolts and the pouring of the bridge deck system in the later stage. Therefore, a construction method to improve the installation and positioning accuracy of the steel box girder is studied in response to this situation. Summary of the invention

[0003] The present invention provides a construction method for improving the installation and positioning accuracy of a steel box girder in order to solve the technical problems existing in the known technology, so as to improve the work efficiency and positioning accuracy and ensure the stability of the entire construction process.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A construction method for improving the installation positioning accuracy of a steel box girder comprises the following steps:

[0006] S1. Use the bracket graded installation method, select a site that does not affect the operation of the crawler crane, and horizontally install steel box beam brackets for hoisting steel box beams in groups of two, with a certain distance L between two adjacent groups of steel box beam brackets; then fix a horizontal distribution beam above the two steel box beam brackets with a distance of L, and the distribution beam is vertically arranged with the steel box beam bracket below it; two groups of positioning plates are also welded on the distribution beam, and the distance between the two groups of positioning plates is greater than the width of the steel box beam, and the positioning plates are a group of two, and the outer side of each positioning plate is reinforced with a diagonal brace;

[0007] S2. Use a double crawler crane to lift the steel box girder onto the distribution beam, and then use the six-point positioning measurement method to measure and fine-tune the position of the steel box girder. Specifically: select an end reference point at each end of the central axis of the steel box girder, measure the x value and y value of the spatial coordinates of the end reference point by a measuring instrument, and adjust them to match the corresponding coordinates in the design drawing; two steel box girder top wing plates are provided on both sides of the top of the steel box girder along the length direction, and two cross partition top plates are provided between the two top wing plates along the width direction of the steel box girder; select an angle reference point at each end of each top wing plate, and adjust the z value of the spatial coordinates of the four angle reference points to match the corresponding coordinates in the design drawing by measuring and adjusting the spatial coordinates. The national geodetic coordinate system is used as a reference;

[0008] S3. After the installation and positioning of the steel box girder is completed, the crawler crane withdraws and prepares to install the next segment of the steel box girder support; repeat the above steps to complete the lifting of the steel box girder, and finally use the temporary access road as the lifting site to lift the remaining steel box girders. The temporary access road is a non-construction area outside the preset area of ​​the steel box girder support.

[0009] As a preferred technical solution, the distance between the two sets of positioning plates in S1 is 15 mm different from the width of the steel box girder.

[0010] As a preferred technical solution, the position of the positioning plate can be obtained through measurement. First, the position of the outermost positioning plate is measured, and then the positions of other groups of positioning plates are calculated based on the width M of the steel box girder and the distance N between two adjacent sections of the steel box girder: assuming that the position of the outermost positioning plate is O, the position of the positioning plate that matches it is O+M+15mm, and the positions of a group of positioning plates adjacent to it are O+M+N and O+M+N+M+15mm respectively.

[0011] As a preferred technical solution, in S2, steel pipe hard supports are provided at the four corners of the top of the distribution beam; specifically, four installation points are pre-designed on the top of the distribution beam, that is, the steel pipe hard supports are fixed at the installation points in groups of two, and a group of steel pipe hard supports are used at both ends of each section of the steel box beam.

[0012] As a preferred technical solution, the upper end cutout of the steel pipe hard support is processed into a cross-section that matches the curvature of the bottom plate of the steel box beam.

[0013] As a preferred technical solution, during the process of measuring and fine-tuning the position of the steel box girder in S2, a dual crawler crane dual-machine step-by-step adjustment method is adopted to fine-tune both ends of the steel box girder: first use a crawler crane to adjust one end of the steel box girder, and then adjust the other end of the steel box girder after completion until the steel box girder reaches the installation position.

[0014] As a preferred technical solution, the end reference point in S2 can be determined by any of the following two methods:

[0015] A) Draw diagonal lines in the rectangular cross-sectional area at each end of the steel box girder. The intersection of the diagonal lines is temporarily set as the end reference point. Then use a measuring ruler to check whether the center point of the rectangular cross-sectional area coincides with the intersection of the diagonal lines. If they coincide, the line connecting the two end reference points at both ends of the steel box girder is taken as the center axis of the steel box girder;

[0016] B) Using an observation position higher than the top plate of the diaphragm, diagonal lines are drawn in the rectangular area at the top of the top plate of the diaphragm at each end of the steel box girder. The intersection of the diagonals is temporarily set as the end reference point. A measuring ruler is then used to check whether the center point of the rectangular area coincides with the intersection of the diagonals. If so, the intersection of the diagonals is determined as the end reference point.

[0017] The advantages and positive effects of the present invention are:

[0018] Compared with the prior art, the construction method for improving the installation positioning accuracy of the steel box girder created by the present invention has the following advantages:

[0019] (1) The construction method for improving the installation and positioning accuracy of the steel box girder described in the present invention improves the installation and positioning method of the transmission bridge, improves the work efficiency and positioning accuracy, and ensures the stability of the entire construction process. The use of the bracket hierarchical installation method solves the problems of limited hoisting space and difficult rotation of the crawler crane boom, realizes the rational use of the construction site, reduces the risk of the hoisting process, and ensures the smooth progress of the project;

[0020] (2) Through the limiting positioning function of the positioning plate, the lifting adjustment range is reduced, avoiding the trouble caused by large-scale adjustments in the later stage;

[0021] (3) The use of double crawler cranes reduces the difficulty of the lifting and adjustment process, reduces the destructiveness of the lifting site during the construction process, and improves the safety of the entire lifting process;

[0022] (4) The six-point positioning measurement method is used to measure the x and y values ​​of the end reference points at both ends of the steel box girder and the z values ​​of the four corner reference points at the top, reducing 12 measurement values ​​to 8. This reduces the measurement value of each section of the steel box girder, making it easier to control the points with the two crawler cranes during positioning and adjustment. The degree of mutual influence between the reference points during measurement is relatively small, and the measured data is more accurate, saving time and improving efficiency.

[0023] (5) A cutting saw is used instead of flame cutting. The oblique cut of the steel pipe hard support obtained by cutting is smooth and consistent with the curvature of the bottom plate of the steel box girder, which improves the stability of the installation process and improves the installation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a stent-by-stent installation method according to an embodiment of the present invention;

[0025] Figure 2 A front view of a steel box beam support according to an embodiment of the present invention;

[0026] Figure 3 A side view of a steel box girder support according to an embodiment of the present invention;

[0027] Figure 4 A front view of a steel box girder according to an embodiment of the present invention;

[0028] Figure 5 This is a top view of the steel box girder described in an embodiment of the present invention.

[0029] Description of reference numerals:

[0030] 1-steel box girder support; 2-steel box girder support preset area; 21-temporary access road; 3-steel box girder; 31-steel box girder I; 32-steel box girder II; 33-steel box girder III; 4-crawler crane; 5-concrete pier; 6-steel pipe hard support; 7-distribution beam; 8-positioning plate; 9-diagonal brace; 101-end reference point; 102-corner reference point; 11-diaphragm top plate; 12-wing plate; 13-rectangular cross-section area. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0032] like Figure 1-5 As shown, the present invention provides a construction method for improving the installation positioning accuracy of a steel box girder, comprising the following steps:

[0033] 1) A bracket grading installation method is adopted, and steel box beam brackets 1 for hoisting steel box beams 3 are installed horizontally in groups of two, and a certain distance L is left between two adjacent groups of steel box beam brackets 1; the steel box beam bracket preset area 2 that affects the crawler crane 4 entering and exiting the construction position and the crawler crane boom swing operation is not installed first;

[0034] Then, a horizontal distribution beam 7 is fixed above the two steel box beam supports 1 with a distance of L, and the distribution beam 7 is vertically arranged with the steel box beam support 1 below it; four installation points of the steel pipe hard support 6 are pre-designed at the four corners of the top of the distribution beam 7, that is, the steel pipe hard support 6 is a group of two, and a group of steel pipe hard support 6 is used at both ends of each section of the steel box beam 3; the installation points are determined to ensure that the steel pipe hard support 6 is in full contact with the bottom plate of the steel box beam, and the steel pipe hard support 6 needs to be welded to the corresponding installation points during installation; preferably, the upper end cutout of the steel pipe hard support 6 needs to be processed into a cross-section that matches the curvature of the bottom plate of the steel box beam;

[0035] Preferably, Figure 2 , Figure 3 As shown, two sets of positioning plates 8 are welded on the distribution beam 7. The positioning plates 8 are a set of two and are located outside the steel pipe hard support 6. The distance between the two sets of positioning plates 8 is greater than the width of the steel box beam 3. The difference between the distance and the width of the steel box beam is 15 mm. The outer side of each positioning plate 8 is reinforced with a diagonal brace 9.

[0036] The position of the positioning plate 8 can be obtained through measurement. The specific operation is: measure the position of the outermost positioning plate, and calculate the positions of other groups of positioning plates according to the width M of the steel box girder 3 and the distance N between two adjacent sections of the steel box girder 3. For example: the position of the outermost positioning plate is O, and the position of a positioning plate matching it is O+M+15mm, and the positions of a group of positioning plates adjacent to it are O+M+N and (O+M+N)+M+15mm respectively.

[0037] 2) The steel box girder 3 is hoisted to the upper ends of the four steel pipe hard supports 6 by a double crawler crane, and then the position of the steel box girder 3 is measured and fine-tuned by a six-point positioning measurement method. Specifically: an end reference point 101 is selected at each end of the central axis of the steel box girder, and the x value and y value of the spatial coordinates of the end reference point 101 are measured by a measuring instrument, and adjusted to coincide with the corresponding coordinates in the design drawing; it is known that two steel box girder top wing plates 12 are provided on both sides of the top of the steel box girder 3 along the length direction, and two cross partition top plates 11 are provided between the two top wing plates 12 along the width direction of the steel box girder 3; the present invention selects an angular reference point 102 at each end of each top wing plate 12, and adjusts the z values ​​of the spatial coordinates of the four angular reference points 102 to coincide with the corresponding coordinates in the design drawing by measuring and adjusting the spatial coordinates, and the spatial coordinates are referenced to the 2000 National Geodetic Coordinate System.

[0038] After the installation and positioning of the steel box girder 3 is completed, the crawler crane 4 withdraws and prepares to install the next segment of the steel box girder support; repeat the above steps to complete the lifting of the steel box girder, and finally use the temporary access road 21 as the lifting site to lift the remaining steel box girders. The temporary access road 21 is a non-construction area outside the preset area 2 of the steel box girder support.

[0039] Preferably, during the measurement and fine-tuning process described in step 2), the two ends of the steel box girder are fine-tuned by using a dual crawler crane and dual machine step-by-step adjustment method: first, one end of the steel box girder is adjusted using a crawler crane, and then the other end of the steel box girder is adjusted after completion until the steel box girder reaches the installation position.

[0040] Preferably, the end reference point 101 in step 2) can be determined by any one of the following two methods:

[0041] A) If Figure 4 As shown, a diagonal line is drawn in the rectangular cross-sectional area 13 at each end of the steel box girder 3, and the intersection of the diagonal lines is temporarily set as the end reference point 101. Then a measuring ruler is used to check whether the center point of the rectangular cross-sectional area 13 coincides with the intersection of the diagonal lines. If they coincide, the line connecting the two end reference points 101 at both ends of the steel box girder 3 is used as the center axis of the steel box girder;

[0042] B) Figure 5 As shown, an observation position higher than the diaphragm top plate 11 is used to draw diagonal lines in the rectangular area on the top of the diaphragm top plate at each end of the steel box girder 3. The intersection of the diagonals is temporarily determined as the end reference point 101. A measuring ruler is then used to check whether the center point of the rectangular area coincides with the intersection of the diagonals. If so, the intersection of the diagonals is determined as the end reference point 101.

[0043] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A construction method for improving the installation positioning accuracy of a steel box girder, characterized in that: The steps include: S1. Use the bracket graded installation method, select a site that does not affect the operation of the crawler crane, and horizontally install steel box beam brackets for hoisting steel box beams in groups of two, with a certain distance L between two adjacent groups of steel box beam brackets; then fix a horizontal distribution beam above the two steel box beam brackets with a distance of L, and the distribution beam is vertically arranged with the steel box beam bracket below it; two groups of positioning plates are also welded on the distribution beam, and the distance between the two groups of positioning plates is greater than the width of the steel box beam, and the positioning plates are a group of two, and the outer side of each positioning plate is reinforced with a diagonal brace; S2. Use a double crawler crane to lift the steel box girder onto the distribution beam, and then use the six-point positioning measurement method to measure and fine-tune the position of the steel box girder. Specifically: select an end reference point at each end of the central axis of the steel box girder, measure the x value and y value of the spatial coordinates of the end reference point by a measuring instrument, and adjust them to match the corresponding coordinates in the design drawing; two steel box girder top wing plates are provided on both sides of the top of the steel box girder along the length direction, and two cross partition top plates are provided between the two top wing plates along the width direction of the steel box girder; select an angle reference point at each end of each top wing plate, and adjust the z value of the spatial coordinates of the four angle reference points to match the corresponding coordinates in the design drawing by measuring and adjusting the spatial coordinates. The national geodetic coordinate system is used as a reference; In S2, during the measurement and fine-tuning of the position of the steel box girder, the two ends of the steel box girder are fine-tuned by using a double crawler crane double machine step-by-step adjustment method: first, one end of the steel box girder is adjusted by a crawler crane, and then the other end of the steel box girder is adjusted after completion, until the steel box girder reaches the installation position; S3. After the steel box girder installation and positioning is completed, the crawler crane withdraws and prepares to install the next section of the steel box girder support; Repeat the above steps to complete the lifting of the steel box girder, and finally use the temporary access road as the lifting site to lift the remaining steel box girders. The temporary access road is a non-construction area outside the preset area of ​​the steel box girder support.

2. The construction method for improving the installation and positioning accuracy of a steel box girder according to claim 1, characterized in that: The difference between the distance between the two sets of positioning plates in S1 and the width of the steel box girder is 15 mm.

3. The construction method for improving the installation and positioning accuracy of a steel box girder according to claim 2, characterized in that: The position of the locating plate can be obtained through measurement. First, the position of the outermost locating plate is measured. According to the width M of the steel box girder and the distance N between two adjacent steel box girder sections, the positions of other groups of locating plates are calculated: assuming that the position of the outermost locating plate is O, the position of the locating plate matching it is O+M+15mm, and the positions of the adjacent group of locating plates are O+M+N and O+M+N+M+15mm respectively.

4. The construction method for improving the installation and positioning accuracy of a steel box girder according to claim 1, characterized in that: In S2, steel pipe hard supports are provided at the four corners of the top of the distribution beam; specifically, four installation points are pre-designed on the top of the distribution beam, that is, the steel pipe hard supports are fixed at the installation points in groups of two, and a group of steel pipe hard supports is used at both ends of each section of the steel box beam.

5. The construction method for improving the installation and positioning accuracy of a steel box girder according to claim 4, characterized in that: The upper end cutout of the steel pipe hard support is processed into a cross section that matches the curvature of the bottom plate of the steel box beam.

6. The construction method for improving the installation and positioning accuracy of a steel box girder according to claim 1, characterized in that: The end reference point in S2 can be determined by any of the following two methods: A) Draw diagonal lines in the rectangular cross-sectional area at each end of the steel box girder. The intersection of the diagonal lines is temporarily set as the end reference point. Then use a measuring ruler to check whether the center point of the rectangular cross-sectional area coincides with the intersection of the diagonal lines. If they coincide, the line connecting the two end reference points at both ends of the steel box girder is used as the center axis of the steel box girder; B) Using an observation position higher than the top plate of the diaphragm, diagonal lines are drawn in the rectangular area on the top of the diaphragm top plate at each end of the steel box girder. The intersection of the diagonals is temporarily set as the end reference point. A measuring ruler is then used to check whether the center point of the rectangular area coincides with the intersection of the diagonals. If so, the intersection of the diagonals is determined as the end reference point.

Images