Optimized structure and construction method of stress of transverse bulkhead at turning position of steel box girder bottom plate

Abstract

The application discloses a kind of steel box girder bottom plate turning place diaphragm stress optimization structure and construction method, structure includes top plate and is located at the bottom of top plate bottom plate, the both ends of bottom plate main body are formed into turning portion by turning up, the both ends of bottom plate turning portion are equipped with inclined bottom plate, diaphragm is equipped between the inclined bottom plate and top plate, and top plate, bottom plate, inclined bottom plate and side web are jointly constituted one cavity, multiple diaphragms are arranged in the cavity along its longitudinal bridge direction interval, and diaphragm is fixedly connected with the inside of top plate, bottom plate, inclined bottom plate and side web, and the inside of top plate, bottom plate, inclined bottom plate and side web is equipped with multiple stiffening ribs arranged at intervals, and the both sides of bottom plate turning portion and diaphragm junction are equipped with corner point stiffening plate or the stiffening rib in bottom plate is arranged in bottom plate turning portion.The application can transmit the resultant force of bottom plate turning portion to the more distant position of diaphragm, avoid stress concentration in turning portion, can optimize the stress distribution of diaphragm, improve the safety and durability of structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bridge engineering, and more particularly to a stress-optimized structure of a transverse diaphragm at a turning point of a steel box girder bottom plate and a construction method. BACKGROUND

[0002] Under the background of the vigorous development of domestic infrastructure construction, large bridge construction projects are emerging like mushrooms, and their construction speed is impressive. Steel box girder, with its excellent mechanical properties, high strength-to-weight ratio and good adaptability, has become one of the preferred structural forms for many bridge engineers in designing various types of bridges, and is widely used in continuous girder bridges, arch bridges, cable-stayed bridges and suspension bridges and other complex bridge systems, playing a crucial role in the construction of China's transportation network and bearing heavy traffic transportation tasks, effectively promoting economic exchanges and development between regions.

[0003] However, the detailed design of the steel box girder often becomes a key factor in determining its overall performance during long-term use, especially at the junction of the bottom plate and the inclined bottom plate. Stress concentration problems threaten the service life and safety of the steel box girder at all times. From the perspective of mechanics, when the steel box girder is in normal working condition, the bottom plate and the inclined bottom plate jointly bear the pressure load transmitted from the upper structure. According to the classical principle of force combination, a resultant force pointing to the inside corner will be formed at the corner intersection of the two, and the transverse diaphragm in this area is usually constructed with a sharp corner. This construction form is a relatively unfavorable stress distribution pattern in mechanics. When the above-mentioned resultant force acts on the transverse diaphragm with a sharp corner structure, due to the sudden change of the force transmission path and the geometric discontinuity of the structure, the stress will be sharply concentrated on the transverse diaphragm, as well as on the bottom plate and the inclined bottom plate connected thereto. Once the internal force generated by this stress concentration exceeds the ultimate strength that the material can withstand, the material may yield, causing irreversible plastic deformation of the internal microstructure of the steel, which in turn leads to a significant decrease in the carrying capacity of the entire structure, making it unable to meet the strict requirements of the design specification for strength, stiffness and stability, affecting the safety and service life of the bridge.

[0004] In the traditional method, most of the solutions are to set triangular stiffening ribs at the junction of the steel box girder bottom plate and the inclined bottom plate, so as to relieve stress concentration by increasing stiffness, the size of the triangular stiffening ribs is large, and the stress of the triangular stiffening ribs is defective, so it is necessary to set stiffening ribs on the triangular stiffening ribs to improve the stress, and due to the longitudinal connection joint of the bottom plate and the inclined bottom plate at the junction of the steel box girder bottom plate and the inclined bottom plate, the setting of the triangular stiffening ribs will cause the overlap of the weld, so a backing plate is set under the triangular stiffening ribs, which improves the stress to a certain extent, but the overall structure is still complex, and the construction process is not clear. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a steel box girder bottom plate turning point diaphragm stress optimization structure and construction method, by setting corner point stiffening plates on both sides of the junction of the bottom plate turning point and the diaphragm, or setting the stiffening ribs in the bottom plate at the bottom plate turning point, when the bottom plate and the inclined bottom plate are subjected to tension and force synthesis, the resultant force will act on the stiffening ribs or the corner point stiffening plates, the stiffening ribs or the corner point stiffening plates will transmit the resultant force to a farther position of the diaphragm, avoiding excessive stress concentration at the turning point, which can effectively optimize the stress distribution of the diaphragm, reduce the high stress area, thereby improving the safety and durability of the structure, making the structure stress more reasonable and uniform. Prolong the service life of the bridge, the stiffening ribs or the corner point stiffening plates are made together with the main structure of the steel box girder, which has simple structure, clear stress, significant effect, convenient construction, strong applicability, and almost no additional cost, greatly improving the convenience of construction, using the same technical requirements as the main structure, the finished product quality is easy to guarantee.

[0006] In order to achieve the above purpose, according to one aspect of the present application, a steel box girder bottom plate turning point diaphragm stress optimization structure is provided, which comprises a top plate arranged at the bottom of the bridge deck, the bottom of the top plate is provided with a bottom plate, the two ends of the main body of the bottom plate are upwardly turned to form turning parts, and the turning parts and the main body of the bottom plate jointly constitute a bottom plate;

[0007] A plurality of middle webs extending along the longitudinal direction of the bridge are arranged between the top plate and the bottom plate, inclined bottom plates are fixedly installed at the two ends of the turning parts, side webs are fixedly installed between the inclined bottom plates and the top plate, the top plate, the bottom plate, the inclined bottom plates and the side webs jointly constitute a cavity, a plurality of diaphragms are arranged in the cavity along the longitudinal direction of the bridge, the diaphragms are fixedly connected to the inner sides of the top plate, the bottom plate, the inclined bottom plates and the side webs, and a plurality of stiffening ribs are arranged at intervals on the inner sides of the top plate, the bottom plate, the inclined bottom plates and the side webs;

[0008] Corner point stiffening plates are arranged on both sides of the junction of the bottom plate turning point and the diaphragm, the corner point stiffening plates are perpendicular to the diaphragm, which is used to improve the stress concentration of the diaphragm at the bottom plate turning point, optimize the stress distribution of the diaphragm, and reduce the high stress area.

[0009] Further, the bottom plate body is twice turned up at both ends to form two turning parts, when the bottom plate stiffening rib is a closed stiffening rib, the width near the turning part of the bottom plate matches the spacing between the two webs of the closed stiffening rib, and the stiffening rib is arranged near the turning part of the bottom plate; when the bottom plate stiffening rib is an open stiffening rib, two stiffening ribs are arranged at the turning parts near the ends of the turning part of the bottom plate.

[0010] Further, the stiffening rib includes but is not limited to a closed type and an open type.

[0011] Further, the cross partition plate includes but is not limited to a solid web type and a hollow web type.

[0012] Further, the connection between the inclined bottom plate and the turning part of the bottom plate is achieved by welding or a pre-tightening piece.

[0013] Further, the corner point stiffening plate is connected to the bottom plate and the cross partition plate by welding.

[0014] Further, the corner point stiffening plate evenly distributes the obtuse angles at the bending parts of the bottom plate.

[0015] Further, the corner point stiffening plates on both sides of the cross partition plate are a whole piece, a hole in the shape of the corner point stiffening plate is formed on the cross partition plate, the corner point stiffening plate is passed through the hole and welded to the turning part of the bottom plate and the cross partition plate.

[0016] Further, the stiffening rib arranged at the turning part of the bottom plate is specially made to match the stiffening rib, and the thickness and size of the stiffening rib are adjusted according to the stress condition.

[0017] According to the second aspect of the present application, a construction method of a stress optimization structure of a cross partition plate at a turning part of a bottom plate of a steel box girder is provided, including the following steps:

[0018] S100: According to the design drawing, the steel box girder is prefabricated in stages, the steel material meeting the standard is selected, the cutting and forming of the top plate, the bottom plate, the inclined bottom plate, the stiffening rib, the edge web, the cross partition plate, and the middle web are performed, and the necessary surface treatment is performed on all components to ensure the welding quality;

[0019] S200: The top plate, the bottom plate, the inclined bottom plate, the stiffening rib, the edge web, the cross partition plate, and the middle web are sequentially welded to ensure the welding quality;

[0020] S300: If the corner point stiffening plate is used to improve the stress concentration of the cross partition plate at the turning part of the bottom plate, the corner point stiffening plate is welded to the cross partition plate and the turning part of the bottom plate.

[0021] S400: If the measure of increasing the stiffening rib is adopted to improve the stress concentration of the transverse plate at the bottom plate turning part, the two ends of the bottom plate main body need to be turned up twice to form two turning parts, when the bottom plate stiffening rib is a closed stiffening rib, the width close to the turning part of the bottom plate matches the spacing between the two webs of the closed stiffening rib, and the stiffening rib is arranged close to the turning part of the bottom plate; when the bottom plate stiffening rib is an open stiffening rib, two stiffening ribs are arranged at the turning parts of the two ends close to the turning part of the bottom plate;

[0022] S500: The tuyere is fixedly installed on both sides of the steel box girder.

[0023] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0024] 1. The steel box girder bottom plate turning part transverse plate stress optimization structure of the present application, by providing an angle point stiffening plate on both sides of the intersection between the bottom plate turning part and the transverse plate or arranging the stiffening rib in the bottom plate at the bottom plate turning part, when the bottom plate and the inclined bottom plate are subjected to tension and force synthesis, the resultant force will act on the stiffening rib or the angle point stiffening plate, and the stiffening rib or the angle point stiffening plate will transmit the resultant force to a more distant position of the transverse plate, thereby greatly reducing the stress of the angle point of the transverse plate at the bottom plate bending part, effectively optimizing the stress distribution of the transverse plate, reducing the high stress area, and improving the safety and durability of the structure.

[0025] 2. The steel box girder bottom plate turning part transverse plate stress optimization structure of the present application, the stiffening rib or the angle point stiffening plate is made together with the main structure of the steel box girder, which is simple in structure, clear in stress, remarkable in effect, convenient in construction, strong in applicability, and almost does not increase the cost, greatly improving the convenience of construction, adopting the same technical requirements as the main body, and the finished product quality is easy to guarantee.

[0026] 3. The steel box girder bottom plate turning part transverse plate stress optimization structure of the present application, the stiffening rib arranged at the bottom plate turning part can also be specially made according to the requirements, and the thickness and size can be adjusted according to the stress condition, these diversified design choices can flexibly choose the most suitable structure form according to the specific engineering requirements and stress condition, thereby improving the stability and carrying capacity of the structure, adapting to different bridge construction scenes, and enhancing the applicability and practicality of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structure schematic view of the steel box girder bottom plate turning part transverse plate stress optimization structure of the embodiment of the present application;

[0028] Figure 2 It is a turning part structure schematic view of the steel box girder bottom plate turning part transverse plate stress optimization structure of the embodiment of the present application;

[0029] Figure 3A turning structure schematic view of a turning structure of a stress-optimized structure of a transverse bulkhead at a turning position of a steel box girder bottom plate according to an embodiment of the present application;

[0030] Figure 4 A construction method flowchart schematic view of a stress-optimized structure of a transverse bulkhead at a turning position of a steel box girder bottom plate according to an embodiment of the present application.

[0031] In all the drawings, the same reference signs refer to the same technical features, specifically: 1 - top plate, 2 - bottom plate, 3 - inclined bottom plate, 4 - stiffening rib, 5 - side web, 6 - transverse bulkhead, 7 - middle web, 8 - corner point stiffening plate, 9 - wind scoop. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0033] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly.

[0034] In addition, if the embodiments of the present application involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes and should not be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features with "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present application.

[0035] In this patent, the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the elements defined by the statement "comprise" do not exclude the presence of other identical elements in the process, method, article or equipment comprising the elements.

[0036] Example 1

[0037] like Figures 1-3 As shown, this embodiment of the invention provides an optimized structure for the stress of the transverse diaphragm at the turning point of the bottom plate of a steel box girder. It includes a top plate 1 located at the bottom of the bridge deck, a bottom plate 2 at the bottom of the top plate 1, and a turning section formed by the upward turning of both ends of the main body of the bottom plate 2. The turning section and the main body of the bottom plate together constitute the bottom plate 2. Multiple intermediate web plates 7 extending longitudinally along the bridge are provided between the top plate 1 and the bottom plate 2. Inclined bottom plates 3 are fixedly installed at both ends of the turning section of the bottom plate 2, with an obtuse angle between the bottom plate 2 and the inclined bottom plates 3. A side web plate 5 is fixedly installed between the inclined bottom plate 3 and the top plate 1. The top plate 1, bottom plate 2, inclined bottom plate 3, and side web plate 5 together form a cavity. Multiple transverse diaphragms 6 are spaced apart along the longitudinal direction of the cavity. The transverse diaphragms 6 are fixedly connected to the inner sides of the top plate 1, bottom plate 2, inclined bottom plate 3, and side web plate 5. Multiple stiffening ribs 4 are spaced apart on the inner sides of the top plate 1, bottom plate 2, inclined bottom plate 3, and side web plate 5. Vents 9 are fixedly installed on the outer sides of the side web plate 5 at both ends of the transverse direction of the cavity. The top plate 1, bottom plate 2, inclined bottom plate 3, and side web plate 5 together form a closed cavity structure, which can significantly improve the load-bearing capacity of the bridge. The top plate 1 bears the upper load, the bottom plate 2 provides support and enhances structural stability, and the inclined bottom plate 3 and side web plate 5 serve to connect and transfer the load. The diaphragm 6 and stiffening rib 4 further enhance the overall integrity and rigidity of the structure, enabling the bridge to better withstand various loads. The two ends of the main body of the bottom plate 1 turn upwards to form a turning section, which, together with the main body of the bottom plate 2, constitutes a complete bottom plate structure, enhancing the torsional stiffness of the bottom plate 2 and improving the stability of the bridge. The wind nozzle 9 helps reduce wind resistance and the impact of wind loads on the bridge, further improving the stability of the bridge. The diaphragm 6 helps limit the distortion and lateral bending deformation of the steel box girder, maintain the cross-sectional shape of the box girder, and reduce the adverse effects caused by load eccentricity. In particular, the diaphragms at the supports can disperse the support reaction force and reduce the impact of local loads on the structure. The stiffening rib 4 enhances the local stiffness of the diaphragm 6 and adjacent plates, improving the structure's resistance to local loads.

[0038] Corner stiffening plates 8 are provided on both sides of the junction between the bottom plate 2 and the transverse diaphragm 6. The corner stiffening plates 8 are perpendicular to the transverse diaphragm 6. The corner stiffening plates 8 increase the local stiffness at the junction between the bottom plate 2 and the transverse diaphragm 6, so that this area can better bear the loads from the upper part and the surrounding area of ​​the bridge. By being perpendicular to the transverse diaphragm 6, the corner stiffening plates 8 can more effectively transfer and distribute the load, avoid excessive stress concentration at the junction, thereby enhancing the strength and stability of the overall structure. The corner stiffening plates 8 can reduce structural damage and fatigue failure caused by stress concentration, making the structural stress more reasonable and uniform, and extending the service life of the bridge.

[0039] Further, the stiffening rib 4 includes but is not limited to closed and open structural forms. The closed stiffening rib has higher torsional stiffness and carrying capacity due to its closed structural characteristics, and is particularly suitable for situations that need to withstand larger lateral loads or torsional loads. Its cross-sectional shape can be designed as rectangular, circular, oval, etc., depending on the stress analysis and design requirements. The closed stiffening rib can also effectively prevent moisture intrusion, reduce corrosion risk, and prolong the service life of the structure. The open stiffening rib is characterized by its lightweight, easy processing and cost-effectiveness, and is suitable for situations with relatively small loads or strict requirements on material weight. The cross-sectional form of the open stiffening rib can be angle steel, channel steel, etc., and its opening direction can be optimized according to the stress direction to improve material utilization efficiency. The most suitable structural form can be selected according to the specific stress conditions and design requirements, thereby improving the stability and carrying capacity of the structure.

[0040] Further, the cross diaphragm 6 includes but is not limited to solid-web and open-web structural forms. The connection between the inclined bottom plate 3 and the transition of the bottom plate 2 is achieved by welding or pre-tightening. By using different forms of stiffening ribs 4 (closed or open) and cross diaphragms 6 (solid-web or open-web), the solid-web cross diaphragm is known for its good integrity, large stiffness, and strong carrying capacity, and is suitable for situations that need to withstand large vertical and horizontal loads. The solid-web cross diaphragm is usually designed as rectangular or circular, and its size and thickness need to be calculated and determined according to the specific stress conditions. The open-web cross diaphragm realizes lightweight design while ensuring certain carrying capacity, and is suitable for situations with strict requirements on structural weight, such as large-span bridges. The open-web cross diaphragm can also be locally reinforced according to the stress needs to improve its carrying capacity. The most suitable structural form can be selected according to the specific stress conditions and design requirements, thereby improving the stability and carrying capacity of the structure.

[0041] Further, the corner point stiffening plate 8 is connected to the bottom plate 2 and the cross diaphragm 6 by welding, and the corner point stiffening plate 8 evenly distributes the obtuse angle at the bend of the bottom plate 2. This not only optimizes stress distribution and reduces the occurrence of high stress areas, but also improves the overall carrying capacity and durability of the structure. By dispersing stress, the corner point stiffening plate 8 effectively reduces the stress concentration degree of the cross diaphragm corner point at the bottom plate bend, thereby prolonging the service life of the structure and reducing maintenance and replacement costs caused by stress concentration.

[0042] Furthermore, the corner stiffening plates 8 on both sides of the diaphragm 6 can be made as a single piece. A hole shaped like the corner stiffening plate 8 is made in the diaphragm 6, through which the corner stiffening plate 8 passes and is welded to the diaphragm 6 at the junction of the base plate 2. As a single piece, the corner stiffening plate 8, compared to the traditional multi-piece splicing method, can better coordinate the force transmission at the junction of the diaphragm 6 and the base plate 2, significantly improving the overall integrity of the structure and effectively resisting various complex external forces. Only a single hole of a specific shape needs to be made in the diaphragm 6, reducing the cumbersome steps of separately positioning and installing multiple corner stiffening plates in traditional construction, simplifying the construction process, and reducing construction difficulty and labor costs. At the same time, the installation accuracy of a single corner stiffening plate 8 is easier to control, helping to improve overall construction quality and efficiency, and shorten the construction cycle. Especially for large-scale projects, it can effectively save time and resource costs.

[0043] Example 2

[0044] like Figure 3 As shown, this embodiment of the invention provides another optimized structure for the stress of the transverse diaphragm at the turning point of the bottom plate of a steel box girder. In this embodiment, the other contents are the same as those in Embodiment 1. The only difference from Embodiment 1 is that the two ends of the main body of the bottom plate 2 turn upward twice to form two turning parts. The two turning parts and the main body of the bottom plate together constitute the bottom plate 2. When the stiffening rib 4 of the bottom plate is a closed stiffening rib, the width near the turning point of the bottom plate 2 matches the distance between the two web plates of the closed stiffening rib, and the stiffening rib 4 is set at the turning point near the bottom plate 2. When the stiffening rib 4 of the bottom plate is an open stiffening rib, two stiffening ribs 4 are set at the turning points near the two ends of the turning point of the bottom plate 2.

[0045] When the base plate 2 and the inclined base plate 3 are subjected to tension and the resultant force is applied to the stiffening rib 4, the stiffening rib 4 transmits the resultant force to a more distant position on the diaphragm, thereby greatly reducing the stress at the corner of the diaphragm at the bend of the base plate. This can effectively optimize the stress distribution of the diaphragm, reduce high-stress areas, and thus improve the safety and durability of the structure. The stiffening rib 4 enhances the local stability at the bend of the base plate and prevents structural deformation or damage caused by stress concentration. The stiffening rib 4 is directly set at the bend of the base plate with almost no additional cost and improves the convenience of construction.

[0046] Further, the stiffening ribs 4 at the turning parts of the bottom plate 2 are specially made to match the stiffening ribs 4, the thickness and size of which are adjusted according to the stress condition; according to the stress analysis result, the thickness of the stiffening ribs can be adjusted locally or as a whole, the thickness is appropriately increased in the stress concentration area to improve the carrying capacity; in the area with smaller stress, the thickness can be appropriately reduced to reduce the weight, by adjusting the stiffening ribs 4 at the turning parts, the carrying capacity and stress distribution performance of the turning parts are improved, the local stability of the structure is improved, and the stress concentration is reduced, so as to adapt to different engineering requirements, which is helpful to prolong the service life of the structure, improve the fatigue resistance, and reduce the risk of structural damage caused by stress concentration.

[0047] In terms of material selection, the stiffening ribs 4 are the most important carrying elements in the bridge structure, and the material properties directly determine the overall mechanical properties, safety and durability of the structure. High-strength and corrosion-resistant steel is selected as the material for making the stiffening ribs 4 to meet the stringent requirements of the structure for strength and durability. The use of high-strength steel enables the stiffening ribs to maintain excellent carrying capacity and stability under complex and variable load conditions, effectively resisting external impact. The use of corrosion-resistant steel ensures that the stiffening ribs can maintain the integrity and durability of the structure in harsh natural environments such as humidity, salt spray and other corrosive conditions, prolonging the service life of the bridge.

[0048] The material thickness and yield strength of the stiffening ribs 4 also need to be calculated precisely. The determination of the material thickness needs to consider factors such as bending moment, shear force, axial force, etc. based on the specific stress condition of the stiffening ribs in the bridge structure, and through structural mechanics analysis to ensure that the stiffening ribs have sufficient strength and stiffness to resist external forces. The yield strength is related to whether the stiffening ribs will deform plastically or break under extreme load conditions. Based on the mechanical properties of the material and the safety factor of the structure design, the yield strength is accurately calculated to ensure that the stiffening ribs can maintain stability when subjected to combined forces and will not be damaged.

[0049] Example 3

[0050] In combination Figures 1-3 As Figure 4 shown, the present application provides a construction method for optimizing the stress structure of the transverse diaphragm at the turning part of the steel box girder bottom plate, comprising the following steps:

[0051] S100: According to the design drawing, the steel box girder is prefabricated in stages, the steel material meeting the standard is selected, the cutting and forming of the top plate 1, the bottom plate 2, the inclined bottom plate 3, the stiffening rib 4, the edge web 5, the transverse diaphragm 6, and the middle web 7 are carried out, and the necessary surface treatment is carried out on all components to ensure the welding quality;

[0052] S200: Weld the top plate 1, the bottom plate 2, the inclined bottom plate 3, the stiffener 4, the edge web 5, the transverse diaphragm 6, and the middle web 7 in sequence, and ensure the welding quality;

[0053] Before welding, all the plates need to be pretreated, including rust removal, cleaning, alignment, etc., to ensure the quality and reliability of the welded joints. Use positioning fixtures or tooling to accurately align and clamp the parts to eliminate deformation and misalignment during welding. According to the structural characteristics and stress conditions, develop a reasonable welding sequence, and perform visual inspection, non-destructive testing, and mechanical property testing on the welded joints to ensure that the weld quality meets the design requirements.

[0054] S300: If the corner point stiffened plate 8 is used to improve the stress concentration of the transverse diaphragm 6 at the bottom plate 2 transition, weld the corner point stiffened plate 8 with the transverse diaphragm 6 and the bottom plate 2 transition;

[0055] According to the stress distribution of the transverse diaphragm 6 at the bottom plate 2 transition, design the shape, size, and thickness of the corner point stiffened plate 8, accurately place the corner point stiffened plate 8 at the predetermined position of the transverse diaphragm 6 and the bottom plate 2 transition, and use positioning fixtures or tooling to fix it. Weld the corner point stiffened plate 8 with the transverse diaphragm 6 and the bottom plate 2 transition. During welding, the welding deformation and weld quality should be strictly controlled.

[0056] S400: If the stiffener 4 is used to improve the stress concentration of the transverse diaphragm 6 at the bottom plate 2 transition, the two ends of the bottom plate 2 main body need to be folded upward twice to form two transition parts. When the bottom plate stiffener 4 is a closed stiffener, the width near the transition part of the bottom plate 2 matches the spacing between the two webs of the closed stiffener, and the stiffener 4 is set near the transition part of the bottom plate 2. When the bottom plate stiffener 4 is an open stiffener, two stiffeners 4 are set near the transition parts of the two ends of the transition part of the bottom plate 2.

[0057] According to the stress distribution of the transverse diaphragm 6 at the bottom plate 2 transition, design the appropriate size and thickness of the stiffener 4, accurately place the stiffener 4 at the predetermined position of the bottom plate 2 transition, and use positioning fixtures or tooling to fix it. Weld the stiffener 4 with the bottom plate 2 transition. During welding, the welding deformation and weld quality should be strictly controlled.

[0058] S500: Fix and install the wind nozzle 9 on both sides of the steel box girder.

[0059] The steel box girder bottom plate turning place diaphragm stress optimization structure and construction method, through setting the corner point stiffener 8 on both sides of the intersection of the bottom plate 2 turning place and the diaphragm 6 or setting the stiffening rib 4 in the bottom plate 2 turning place in the bottom plate 2, effectively transfer the resultant force of the bottom plate 2 and the inclined bottom plate 3 when being subjected to tensile force and force synthesis to the further position of the diaphragm 6, avoids the excessive stress concentration at the turning place, can significantly optimize the stress distribution of the diaphragm 6, reduces the high stress area, improves the safety and durability of the structure, the setting of the corner point stiffener 8 or the stiffening rib 4 increases the local stiffness of the intersection of the bottom plate 2 turning place and the diaphragm 6, so that the area can better bear the load from the bridge upper part and the periphery, helps to prevent the structural deformation or damage caused by stress concentration, improves the strength and stability of the overall structure, the connection mode of the corner point stiffener 8, the bottom plate 2 and the diaphragm 6 adopts welding, so that the construction is more convenient and fast, improves the construction efficiency.

[0060] Those skilled in the art will easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A stress-optimized structure of a transverse diaphragm at a turn of a steel box girder bottom plate, characterized by, It includes the top plate (1) arranged at the bottom of the bridge deck, the bottom of the top plate (1) is provided with the bottom plate (2), the two ends of the main body of the bottom plate (2) are upwardly folded to form the turning portions, and the turning portions and the main body of the bottom plate (2) jointly constitute the bottom plate (2); A plurality of middle webs (7) extending along the longitudinal direction of the bridge are arranged between the top plate (1) and the bottom plate (2), the two ends of the turning portions are fixedly provided with the inclined bottom plates (3), the inclined bottom plates (3) and the top plate (1) are fixedly provided with the side webs (5), the top plate (1), the bottom plate (2), the inclined bottom plate (3) and the side web (5) jointly constitute a cavity, a plurality of transverse webs (6) are arranged in the cavity along the longitudinal direction of the cavity, the transverse webs (6) are fixedly connected to the inner sides of the top plate (1), the bottom plate (2), the inclined bottom plate (3) and the side web (5), and a plurality of stiffening ribs (4) are arranged at intervals in the inner sides of the top plate (1), the bottom plate (2), the inclined bottom plate (3) and the side web (5); The two ends of the main body of the bottom plate (2) are upwardly folded twice to form two turning portions, when the bottom plate stiffening rib (4) is a closed stiffening rib, the width close to the turning portion of the bottom plate (2) matches the spacing between the two webs of the closed stiffening rib, the stiffening rib (4) is arranged at the turning portion close to the bottom plate (2), when the bottom plate stiffening rib (4) is an open stiffening rib, two stiffening ribs (4) are arranged at the turning portions of the two ends close to the turning portion of the bottom plate (2), the stiffening rib (4) in the bottom plate (2) is arranged at the turning portion of the bottom plate (2), when the bottom plate (2) and the inclined bottom plate (3) are subjected to tension and force synthesis, the resultant force will act on the stiffening rib (4), the stiffening rib (4) will transmit the resultant force to a more distant position of the transverse web (6), so that excessive stress concentration is avoided at the turning portion.

2. The stress-optimized structure of a cross diaphragm at a turn of a steel box girder bottom plate according to claim 1, characterized in that, The stiffening rib (4) includes but is not limited to the structure forms of the closed type and the open type.

3. The stress-optimized structure of a cross diaphragm at a turn of a steel box girder bottom plate according to claim 1, characterized in that, The transverse web (6) includes but is not limited to the structure forms of the solid web type and the hollow web type.

4. The stress-optimized structure of a cross diaphragm at a turn of a bottom plate of a steel box girder according to any one of claims 1 to 3, characterized in that, The connection mode of the inclined bottom plate (3) and the turning portion of the bottom plate (2) adopts welding or pre-tightening piece connection.

5. The stress-optimized structure of a cross diaphragm at a turn of a bottom plate of a steel box girder according to any one of claims 1 to 3, characterized in that, The stiffening rib (4) arranged at the turning portion of the bottom plate (2) is specially made according to the requirements, and the thickness and size of the stiffening rib (4) are adjusted according to the stress condition.

6. A construction method of the stress-optimized structure of the cross diaphragm at the turn of the bottom plate of a steel box girder according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S100: according to the design drawing, the steel box girder is prefabricated in stages, the steel materials meeting the standards are selected, the top plate (1), the bottom plate (2), the inclined bottom plate (3), the stiffening rib (4), the side web (5), the transverse web (6) and the middle web (7) are cut and formed, and the necessary surface treatment is performed on all components to ensure the welding quality; S200: the top plate (1), the bottom plate (2), the inclined bottom plate (3), the stiffening rib (4), the side web (5), the transverse web (6) and the middle web (7) are sequentially welded to ensure the welding quality; S300: The measure of increasing the stiffening rib (4) is adopted to improve the stress concentration of the transverse partition plate (6) at the turning part of the bottom plate (2). The two ends of the main body of the bottom plate (2) need to be turned up twice to form two turning parts. When the bottom plate stiffening rib (4) is a closed stiffening rib, the width near the turning part of the bottom plate (2) matches the spacing between the two webs of the closed stiffening rib, and the stiffening rib (4) is arranged near the turning part of the bottom plate (2); when the bottom plate stiffening rib (4) is an open stiffening rib, two stiffening ribs (4) are arranged at the turning parts of the two ends near the turning part of the bottom plate (2); S400: The tuyere (9) is fixedly installed on both sides of the steel box girder.

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