Large-span steel box girder bridge incremental launching construction refined local reinforcing method and structure

Abstract

The invention relates to a refined local reinforcement method and structure for incremental launching construction of a large-span steel box girder bridge. The method comprises the following steps: establishing a finite element bar system model; analyzing to obtain a bearing reaction result of each temporary pier in the whole incremental launching construction process; establishing a standard segment local plate shell model; obtaining a critical bearing reaction value under a local stress limit value of the steel box girder; obtaining the position of the steel box girder section at the temporary pier support counter-force over-limit position; local reinforcement is conducted on the steel box girder sections at the temporary pier bearing counter-force over-limit positions; correcting the rigidity and the mass of the section of the reinforced finite element model of the rod system; the most unfavorable working condition is obtained; and checking the local stress of the most unfavorable working condition of pushing of the reinforced steel box girder to judge whether the local stress requirement is met or not. The method can accurately judge the position of the steel box girder segment at the position where the temporary pier supporting reaction force exceeds the limit in the steel box girder pushing process, improves the economic benefit and saves the construction time. The local reinforcing structure can be detached independently, is convenient to install in the steel box girder, and can be recycled or reused in the whole bridge according to actual reinforcing working conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of steel box girder jacking construction, and in particular relates to a refined local reinforcement method and structure for jacking construction of a large-span steel box girder bridge. Background Art

[0002] Pushing construction is a common construction method in bridge construction. With the development of materials, equipment and theory, the application of bridge pushing method is becoming more and more widespread. Among them, the walking multi-point pushing technology has a walking translation pushing device and a computing synchronization control system. Compared with the traditional dragging pushing, it can realize the convenient vertical and horizontal adjustment and can better control the reaction force of each temporary pier. Therefore, the walking multi-point pushing construction is widely used in bridge construction.

[0003] During the multi-point jacking construction of steel box girders, the problem of local stress exceeding the limit is usually faced. During the jacking process, the steel box girder is subjected to the reaction force of the temporary pier support. If the reaction force of the temporary pier support is too large, it may cause the local stress exceeding the limit during the jacking process, resulting in local buckling of the steel box girder. The existing local reinforcement method for jacking construction of steel box girders usually uses a bar system model to determine the most unfavorable working condition of the jacking construction, analyzes the local stress state of the most unfavorable working condition, and determines the reinforcement scheme that meets the most unfavorable working condition, so as to reinforce the entire bridge of the jacking section. However, during the jacking process, the reaction force of the temporary pier support changes continuously with the jacking process. Not all steel box girder segments will cause local stress exceeding the limit due to excessive support reaction force. Therefore, reinforcing the entire length of the bridge will make the reinforcement scheme uneconomical and affect construction efficiency.

[0004] The existing top-pushing construction of steel box girders generally adopts two types of reinforcement structures: welding corner stiffeners at the junction of the bottom plate and the web to reinforce the steel box girder; and thickening the plate within a certain range at the junction of the bottom and web. The two top-pushing reinforcement structures cannot be disassembled and remain permanently in the steel box girder during the service life of the bridge, which is not conducive to reuse.

[0005] Therefore, it is necessary to propose a method for local fine reinforcement of steel box girders during jacking construction, determine the length of the reinforced segment of the steel box girder by the support reaction force, formulate a reinforcement plan, and propose a new local reinforcement structure based on the existing local reinforcement structure. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a refined local reinforcement method and structure for the jacking construction of a large-span steel box girder bridge. The inner support rods and the outer support rods can be disassembled by bolts at the anchor plate. After the jacking construction is completed, they can be recycled or the entire bridge can be reused according to the actual reinforcement conditions during the jacking process, thereby improving economic benefits and construction efficiency.

[0007] The present invention solves the technical problem by the following technical solutions:

[0008] A method for fine local reinforcement of top-pushing construction of a large-span steel box girder bridge, the method comprising the following steps:

[0009] S1: The finite element bar system model of the whole process of top-pushing construction of steel box girder bridge was established using the general spatial finite element analysis software Midas / Civil, and the step length of the top-pushing construction stage was set to 1m;

[0010] S2. Conduct finite element analysis of the bar system model during the entire process of jacking construction to obtain the reaction force results of each temporary pier support during the entire process of jacking construction;

[0011] S3. Use the large-scale general finite element analysis software ANSYS to establish the local plate shell model of the standard segment of the large-span steel box girder bridge top-pushing construction;

[0012] S4, applying the support reaction force as a load to the unfavorable position between the transverse diaphragms of the steel box girder, and calculating the critical support reaction force value under the local stress limit of the steel box girder;

[0013] S5. Use the critical support reaction value to determine the location of the steel box girder segment where the temporary pier support reaction exceeds the limit during the entire process of jacking construction;

[0014] S6. Locally strengthen the steel box girder segment where the reaction force of the temporary pier exceeds the limit;

[0015] S7, Section stiffness and mass of the finite element bar model after correction and strengthening;

[0016] S8. Repeat S2 to calculate the support reaction force during the entire process of the reinforced push construction to obtain the most unfavorable working condition;

[0017] S9. Check the local stress of the most unfavorable working condition of the steel box girder after strengthening. If it does not meet the local stress requirements, return to S5 to add a reinforced section. If it meets the local stress requirements, complete the strengthening.

[0018] Moreover, S5 specifically adopts the local plate shell model of the steel box girder to determine the temporary pier support reaction limit under the local stress limit of the steel box girder, and judges the support reaction during the whole process of jacking construction. If the temporary pier support reaction is less than the support reaction limit, the steel box girder at the temporary pier under this working condition will not be locally strengthened; if the temporary pier support reaction is greater than or equal to the support reaction limit, the steel box girder at the temporary pier under this working condition needs to be locally strengthened.

[0019] A refined local reinforcement structure for jacking construction of a large-span steel box girder bridge adopts the refined local reinforcement method for jacking construction of a large-span steel box girder bridge, including a web reinforcement plate and a bottom plate reinforcement plate, the web reinforcement plate and the bottom plate reinforcement plate are arranged at the same angle according to the web and bottom plate of the steel box girder, the web reinforcement plate and the bottom plate reinforcement plate are connected to an inner support rod, the two ends of the inner support rod are respectively fixedly connected to the web reinforcement plate and the bottom plate reinforcement plate by bolts, the web reinforcement plate and the bottom plate reinforcement plate are also connected to an outer support rod, the outer support rod includes an adjusting rod and an adjusting sleeve provided with positive and negative threaded openings, the adjusting rods are arranged at both ends of the adjusting sleeve, the adjusting rods are respectively fixedly connected to the web reinforcement plate and the bottom plate reinforcement plate by bolts, the web reinforcement plate and the bottom plate reinforcement plate are respectively adhesively connected to the outer web of the steel box girder, the inner web of the steel box girder and the bottom plate of the steel box girder.

[0020] The advantages and beneficial effects of the present invention are:

[0021] 1. The present invention can accurately determine the position of the steel box girder segment where the temporary pier support reaction force exceeds the limit during the steel box girder jacking process, provide a reasonable reinforcement plan for the steel box girder jacking construction, improve economic benefits and save construction time.

[0022] 2. The present invention provides measures to improve the local reinforcement of the steel box, reinforce the sections with excessive support reaction forces, and verify the most unfavorable working conditions after reinforcement to ensure the safety of the steel box girder during the jacking process.

[0023] 3. The local reinforcement structure described in the present invention can be separated into its components for easy installation inside the steel box girder. The length of the brace can be adjusted to adapt to the inclination angle of the inclined web. The reinforcement plate is tightly attached to the steel box girder to reinforce the web and bottom plate. The brace can prevent local buckling of the steel box girder during the jacking process. The inner brace and the outer brace can be disassembled by bolts at the anchor plate. After the jacking construction is completed, they can be recycled or reused throughout the bridge according to the actual reinforcement conditions during the jacking process, thereby improving economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the process of the present invention;

[0025] Figure 2 It is a structural schematic diagram of the steel box girder top-pushing construction process according to an embodiment of the present invention;

[0026] Figure 3 It is a cross-sectional view of a standard section of a steel box girder at a temporary pier section according to an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of a local reinforcement segment determined in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the local reinforcement structure of the present invention;

[0029] Figure 6 This is a schematic diagram of the installation position of the local reinforcement structure described in an embodiment of the present invention inside the steel box girder.

[0030] Description of Reference Numerals

[0031] 1. Push assembly platform; 2. Temporary pier; 3. Walking jack; 4. Steel main beam; 5. Permanent pier; 6. Guide beam; 7. Outer web of steel box beam; 8. Bottom plate of steel box beam; 9. Inner web of steel box beam; 10. Top plate; 11. Transverse diaphragm; 12. Web reinforcement plate; 13. Bottom plate reinforcement plate; 14. Inner support rod; 15. Outer support rod; 16. Adjustment sleeve; 17. Adjustment rod. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0033] like Figure 1 As shown, a method for fine local reinforcement of a large-span steel box girder bridge in top-pushing construction is innovative in that the steps of the method are:

[0034] Step 1: Use the general spatial finite element analysis software Midas / Civil to establish the finite element bar system model of the entire process of steel box girder jacking construction. Set a jacking condition every 1m during the jacking construction stage to accurately simulate the actual temporary pier reaction force of each condition during the jacking construction process;

[0035] Step 2: Conduct finite element analysis of the bar system model during the entire process of jacking construction to obtain the reaction force variation results of each temporary pier support during the entire process of jacking construction;

[0036] Step 3: Use the large-scale general finite element analysis software ANSYS to establish a local plate shell model of the standard segment of the large-span ultra-wide steel box girder top-pushing construction. According to the Saint-Venant principle, the length of the local model along the bridge direction is 3.0-4.5 times the beam height, and the shell181 unit is used to simulate the stress of the steel box girder;

[0037] Step 4: Apply the support reaction force to the unfavorable position between the transverse diaphragms of the steel box girder, and calculate the critical support reaction force value under the local stress limit of the steel box girder. The transverse diaphragm can enhance the lateral stiffness of the steel box girder, maintain the cross-sectional shape of the steel box girder, and avoid buckling caused by excessive local stress. Therefore, when the support reaction force is between the two transverse diaphragms, the web and the bottom plate are subjected to the most unfavorable force.

[0038] Step 5: Use the critical support reaction value to determine the location of the steel box girder segment where the temporary pier support reaction exceeds the limit during the entire process of jacking construction;

[0039] Step 6: locally strengthen the segmental steel box girder with excessive support reaction force by using the local reinforcement structure described in the present invention;

[0040] Step 7: According to the adopted reinforcement structure, modify the cross-sectional stiffness and mass of the reinforced bar system model. After local reinforcement, the weight of the steel box girder and the cross-sectional stiffness after reinforcement change, resulting in changes in the reaction force of the temporary pier support. The bar system model is modified to simulate the actual stress state of the reinforced steel box girder;

[0041] Step 8: Return to step 2, calculate the support reaction force during the entire process of the reinforced jacking construction, and obtain the most unfavorable working condition;

[0042] Step 9: Check the local stress of the most unfavorable working condition of the reinforced steel box girder under top pushing. If the local stress requirements are not met, return to step 5 to add a reinforced segment. If the local stress requirements are met, the reinforcement plan is obtained.

[0043] like Figures 2 to 4 As shown, a specific embodiment of positioning the local reinforcement segment of a steel box girder is given below.

[0044] The steel box girder is constructed by walking multi-point jacking. The steel main beam 4 is assembled in sections on the assembly platform 1. A walking jack 3 is set on the temporary pier 2 to push the steel main beam 4 to the permanent pier 5 in the direction of the guide beam 6.

[0045] According to the support reaction limit, four reinforced sections L1, L2, L3, L4 and L5 are determined. L1 includes two standard sections B15-B16, L2 includes two standard sections B18-B19, L3 includes five standard sections B15'-B19', L4 includes two standard sections B12'-B13', and L5 includes five standard sections B3'-B7'. The total reinforced length is 144m.

[0046] The steel box girder is composed of an outer web 7, a bottom plate 8, an inner web 9, a top plate 10 and a cross diaphragm 11. The local stresses at the bottom plate 8, the outer web 7 and the inner web 9 of the steel box girder in contact with the top push jack 3 are relatively large and need to be strengthened.

[0047] like Figure 5As shown, a refined local reinforcement structure for top-pushing construction of a large-span steel box girder bridge is innovative in that it includes a web reinforcement plate 12 and a bottom reinforcement plate 13, the web reinforcement plate 12 and the bottom reinforcement plate 13 are arranged at the same angle as the web and bottom of the steel box girder, the web reinforcement plate 12 and the bottom reinforcement plate 13 are connected to an inner support rod 14, the two ends of the inner support rod 14 are respectively fixedly connected to the web reinforcement plate 12 and the bottom reinforcement plate 13 by bolts, and the web reinforcement plate 12 and the bottom reinforcement plate 13 are connected to the web reinforcement plate 12 and the bottom reinforcement plate 13 by bolts. The strong plate 12 and the bottom plate reinforcement plate 13 are also connected to the outer support rod 15, and the outer support rod 15 includes an adjusting rod 17 and an adjusting sleeve 16 provided with positive and negative thread openings. The adjusting rod 17 is provided at both ends of the adjusting sleeve 16. The adjusting rod 17 is fixedly connected to the web reinforcement plate 12 and the bottom plate reinforcement plate 13 by bolts respectively. The web reinforcement plate 12 and the bottom plate reinforcement plate 13 are respectively adhesively connected to the outer web 7 of the steel box girder, the inner web 9 of the steel box girder and the bottom plate 8 of the steel box girder.

[0048] During the construction of the local reinforcement structure, each component of the reinforcement structure can be flexibly disassembled for easy construction and installation. The web reinforcement plate 13 is tightly adhered to the outer web plate 9 of the steel box beam by structural adhesive, and the bottom plate reinforcement plate 14 is tightly adhered to the bottom plate 8 of the steel box beam. The support rod is connected to the reinforcement plate by bolts, and the length of the support rod is adjusted by adjusting the sleeve 15 to support the reinforcement plate, and participate in the force of the steel box beam structure together with the reinforcement plate. Figure 6 As shown, the local reinforcement structure is arranged at the junction of the inner and outer webs and the bottom plate.

[0049] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A refined local reinforcement method for top-pushing construction of a large-span steel box girder bridge, characterized in that: The steps of the method are: S1: The finite element bar system model of the whole process of top-pushing construction of steel box girder bridge was established using the general spatial finite element analysis software Midas / Civil, and the step length of the top-pushing construction stage was set to 1m; S2. Conduct finite element analysis of the bar system model during the entire process of jacking construction to obtain the reaction force results of each temporary pier support during the entire process of jacking construction; S3. Use the large-scale general finite element analysis software ANSYS to establish the local plate shell model of the standard segment of the large-span steel box girder bridge top-pushing construction; S4, applying the support reaction force as a load to the unfavorable position between the transverse diaphragms of the steel box girder, and calculating the critical support reaction force value under the local stress limit of the steel box girder; S5. Use the critical support reaction value to determine the location of the steel box girder segment where the temporary pier support reaction exceeds the limit during the entire process of jacking construction; S6. Locally strengthen the steel box girder segment where the reaction force of the temporary pier exceeds the limit; S7, Section stiffness and mass of the finite element bar model after correction and strengthening; S8. Repeat S2 to calculate the support reaction force during the entire process of the reinforced push construction to obtain the most unfavorable working condition; S9. Check the local stress of the most unfavorable working condition of the steel box girder after strengthening. If it does not meet the local stress requirements, return to S5 to add a reinforced section. If it meets the local stress requirements, complete the strengthening.

2. The method for refined local reinforcement of the jacking construction of a large-span steel box girder bridge according to claim 1 is characterized by: The S5 specifically adopts the local plate shell model of the steel box girder to determine the temporary pier support reaction limit under the local stress limit of the steel box girder, and judges the support reaction during the whole process of jacking construction. If the temporary pier support reaction is less than the support reaction limit, the steel box girder at the temporary pier under this working condition will not be locally strengthened; if the temporary pier support reaction is greater than or equal to the support reaction limit, the steel box girder at the temporary pier under this working condition needs to be locally strengthened.

3. A refined local reinforcement structure for top-pushing construction of a large-span steel box girder bridge, characterized in that: A refined local reinforcement method for top-pushing construction of a long-span steel box girder bridge as claimed in any one of claims 1 and 2 is adopted, comprising a web reinforcement plate (12) and a bottom plate reinforcement plate (13), wherein the web reinforcement plate (12) and the bottom plate reinforcement plate (13) are arranged at the same angle as the web and the bottom plate of the steel box girder, the web reinforcement plate (12) and the bottom plate reinforcement plate (13) are connected to an inner support rod (14), the two ends of the inner support rod (14) are respectively fixedly connected to the web reinforcement plate (12) and the bottom plate reinforcement plate (13) by bolts, and the web reinforcement plate (12) and the bottom plate reinforcement plate (13) are respectively fixedly connected to the web reinforcement plate (12) and the bottom plate reinforcement plate (13) by bolts. 2) An outer support rod (15) is also connected to the bottom plate reinforcement plate (13), and the outer support rod (15) includes an adjustment rod (17) and an adjustment sleeve (16) provided with positive and negative thread holes. The adjustment rod (17) is provided at both ends of the adjustment sleeve (16). The adjustment rod (17) is respectively fixedly connected to the web reinforcement plate (12) and the bottom plate reinforcement plate (13) by bolts. The web reinforcement plate (12) and the bottom plate reinforcement plate (13) are respectively connected to the outer web (7) of the steel box beam, the inner web (9) of the steel box beam and the bottom plate (8) of the steel box beam by corresponding adhesive bonding.

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