Optimization structure and construction method for transverse partition plate stress at turning position of steel box girder bottom plate

Abstract

The invention discloses a steel box girder bottom plate turning position diaphragm plate stress optimization structure and a construction method.The structure comprises a top plate and a bottom plate arranged at the bottom of the top plate, the two ends of a bottom plate body are turned upwards to form turning parts, inclined bottom plates are arranged at the two ends of the turning parts of the bottom plate, and side webs are arranged between the inclined bottom plates and the top plate; the top plate, the bottom plate, the inclined bottom plate and the side web jointly form a cavity, a plurality of transverse partition plates are arranged in the cavity in the longitudinal bridge direction at intervals, the transverse partition plates are fixedly connected with the top plate, the bottom plate, the inclined bottom plate and the inner side of the side web, and a plurality of stiffening ribs are arranged on the inner side of the top plate, the inner side of the bottom plate, the inner side of the inclined bottom plate and the inner side of the side web at intervals. Corner point stiffening plates are arranged on the two sides of the joint of the bottom plate turning position and the transverse partition plate, or stiffening ribs in the bottom plate are arranged at the bottom plate turning position. The resultant force at the turning position of the bottom plate can be transmitted to the farther position of the transverse partition plate, stress concentration at the turning position is avoided, stress distribution of the transverse partition plate can be optimized, and the safety and durability of the structure are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of bridge engineering, and more specifically, relates to an optimized structure for the stress of the diaphragm at the turning of the steel box girder bottom plate and a construction method thereof. Background Art

[0002] Under the background of the booming development of domestic infrastructure construction today, large-scale bridge construction projects have emerged in an endless stream, and their construction speed is remarkable. The 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 when designing various bridge types, and is widely used in various complex bridge type systems such as continuous girder bridges, arch bridges, cable-stayed bridges and suspension bridges. It plays a crucial role in the construction of China's transportation network, undertakes heavy transportation tasks, and effectively promotes economic exchanges and development between regions.

[0003] However, during the long-term use of the steel box girder, the details of its design often become the key factors determining its overall performance. Especially at the critical part where the bottom plate meets the inclined bottom plate, the stress concentration problem always threatens the service life and safety of the steel box girder. From the perspective of mechanical principles, when the steel box girder is in a normal working state and 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 synthesis, at the angular intersection of the two, a resultant force pointing to the inner corner side will be formed. Correspondingly, the diaphragms in this area usually adopt a sharp-angle structure, and this structural form is a relatively unfavorable stress distribution pattern in mechanics. When the above resultant force acts on the diaphragm with a sharp-angle structure, due to the sudden change in the force transmission path and the geometric discontinuity of the structure, the stress will sharply concentrate on the diaphragm and the bottom plate and the inclined bottom plate connected to it. Once the internal force generated by this stress concentration phenomenon exceeds the ultimate strength that the material itself can bear, it is very likely to cause the material to yield, resulting in irreversible plastic deformation of the internal microstructure of the steel, and then leading to a significant decrease in the load-bearing capacity of the entire structure, unable to meet the strict requirements for strength, stiffness and stability in the established design specifications, and affecting the safety and service life of the bridge.

[0004] In traditional methods, most of the solutions are to set triangular stiffeners at the junction of the bottom plate and the inclined bottom plate of the steel box girder, in order to relieve stress concentration by increasing stiffness. The size of the triangular stiffeners used is relatively large, and there are defects in their own stress conditions. Therefore, it is necessary to set stiffeners on the triangular stiffeners to improve the stress conditions. At the same time, since a longitudinal connection seam between the bottom plate and the inclined bottom plate is provided longitudinally and continuously at the junction of the bottom plate and the inclined bottom plate of the steel box girder, the setting of the triangular stiffeners will cause the overlap of welds. Therefore, backing plates are set under the triangular stiffeners. Although the stress conditions are improved to a certain extent, the overall structure is still relatively complex and the construction process is not clear enough. Summary of the Invention

[0005] In view of the above defects or improvement requirements of the prior art, the present invention provides an optimized structure and construction method for the stress of the diaphragm at the turning point of the bottom plate of the steel box girder. By providing corner stiffening plates on both sides of the junction of the bottom plate turning point and the diaphragm or arranging the stiffeners in the bottom plate at the bottom plate turning point, when the bottom plate and the inclined bottom plate are subjected to tensile forces and the forces are synthesized, the resultant force will act on the stiffeners or corner stiffening plates. The stiffeners or corner stiffening plates will transfer the resultant force to a farther position of the diaphragm, avoiding excessive stress concentration at the turning point, effectively optimizing the stress distribution of the diaphragm, reducing the high-stress area, thereby improving the safety and durability of the structure, making the structure more reasonable and uniform in stress. Extending the service life of the bridge, the stiffeners or corner stiffening plates are fabricated together with the main structure of the steel box girder, with simple structure, clear stress, remarkable effect, convenient construction, strong applicability, and almost no additional cost, greatly improving the convenience of construction. Adopting the same technical requirements as the main structure, the quality of the finished product is easy to guarantee.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided an optimized structure for the stress of the diaphragm at the turning point of the bottom plate of the steel box girder, including a top plate provided at the bottom of the bridge deck. A bottom plate is provided at the bottom of the top plate. Both ends of the main body of the bottom plate are turned upward to form a turning portion, and the turning portion and the main body of the bottom plate together form the bottom plate.

[0007] A plurality of middle webs extending longitudinally along the bridge are provided between the top plate and the bottom plate. The inclined bottom plates are fixedly installed at both ends of the turning portion. 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 together form a cavity. A plurality of diaphragms are arranged at intervals along the longitudinal direction of the cavity inside the cavity. The diaphragms are fixedly connected to the inner sides of the top plate, the bottom plate, the inclined bottom plates and the side webs. A plurality of stiffeners arranged at intervals are provided on the inner sides of the top plate, the bottom plate, the inclined bottom plates and the side webs.

[0008] Corner stiffening plates are provided on both sides of the junction of the bottom plate turning point and the diaphragm. The corner stiffening plates are perpendicular to the diaphragm and are 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] Furthermore, both ends of the main body of the bottom plate are turned upward twice to form two turning parts. When the bottom plate stiffener is a closed stiffener, the width near the turning part of the bottom plate matches the distance between the two webs of the closed stiffener, and stiffeners are arranged near the turning part of the bottom plate. When the bottom plate stiffener is an open stiffener, two stiffeners are arranged at the turning points at both ends near the turning part of the bottom plate.

[0010] Furthermore, the stiffeners include, but are not limited to, closed-type and open-type structural forms.

[0011] Furthermore, the diaphragms include, but are not limited to, solid-web and open-web structural forms.

[0012] Furthermore, the connection mode between the inclined bottom plate and the turning part of the bottom plate adopts welding or connection with pre-tightening parts.

[0013] Furthermore, the corner stiffening plates are connected to the bottom plate and the diaphragms by welding.

[0014] Furthermore, the corner stiffening plates evenly distribute the obtuse angles at the bending parts of the bottom plate.

[0015] Furthermore, the corner stiffening plates on both sides of the diaphragm are integral, a hole in the shape of a corner stiffening plate is opened on the diaphragm, and the corner stiffening plates are passed through the holes and welded to the turning parts of the bottom plate and the diaphragms.

[0016] Furthermore, the stiffeners arranged at the turning parts of the bottom plate are specially manufactured according to requirements to match the corresponding stiffeners, and the thickness and size of the stiffeners are adjusted according to the stress conditions.

[0017] According to the second aspect of the present invention, a construction method for an optimized structure of the stress of the diaphragm at the turning part of the steel box girder bottom plate is provided, including the following steps:

[0018] S100: According to the design drawings, prefabricate the steel box girder in stages, select steel that meets the standards, cut and form the top plate, bottom plate, inclined bottom plate, stiffeners, side webs, diaphragms, and middle webs, and perform necessary surface treatment on all components to ensure the welding quality;

[0019] S200: Weld the top plate, bottom plate, inclined bottom plate, stiffeners, side webs, diaphragms, and middle webs in sequence to ensure the welding quality;

[0020] S300: If corner stiffening plates are used to improve the stress concentration of the diaphragm at the turning part of the bottom plate, weld the corner stiffening plates to the diaphragm and the turning part of the bottom plate;

[0021] S400: If the measure of adding stiffeners is adopted to improve the stress concentration at the turning point of the diaphragm plate at the bottom plate, it is necessary to turn up the two ends of the main body of the bottom plate twice to form two turning parts. When the bottom plate stiffener is a closed stiffener, the width near the turning part of the bottom plate matches the distance between the two webs of the closed stiffener, and a stiffener is arranged near the turning part of the bottom plate; when the bottom plate stiffener is an open stiffener, two stiffeners are arranged at the turning points at both ends near the turning part of the bottom plate.

[0022] S500: Fix the wind nozzle on both sides of the steel box girder.

[0023] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0024] 1. For the optimized structure of the stress of the diaphragm plate at the turning point of the bottom plate of the steel box girder of the present invention, by providing corner stiffening plates on both sides at the intersection of the turning point of the bottom plate and the diaphragm plate or arranging the stiffeners in the bottom plate at the turning point of the bottom plate, when the bottom plate and the inclined bottom plate are subjected to tensile forces and force synthesis is performed, the resultant force will act on the stiffeners or corner stiffening plates, and the stiffeners or corner stiffening plates will transfer the resultant force to a farther position of the diaphragm plate. Thus, the stress at the corner of the diaphragm plate at the bending part of the bottom plate is greatly reduced, the stress distribution of the diaphragm plate can be effectively optimized, the high-stress area can be reduced, and the safety and durability of the structure can be improved.

[0025] 2. For the optimized structure of the stress of the diaphragm plate at the turning point of the bottom plate of the steel box girder of the present invention, the stiffeners or corner stiffening plates are fabricated together with the main structure of the steel box girder. The structure is simple, the force is clear, the effect is remarkable, the construction is convenient, the applicability is strong, and the cost is hardly increased. The convenience of construction is greatly improved. By adopting the same technical requirements as the main structure, the quality of the finished product is easy to guarantee.

[0026] 3. For the optimized structure of the stress of the diaphragm plate at the turning point of the bottom plate of the steel box girder of the present invention, the stiffeners arranged at the turning point of the bottom plate can also be specially fabricated according to requirements, and their thickness and size can be adjusted according to the stress conditions. These diversified design options can flexibly select the most suitable structural form according to the specific engineering requirements and stress conditions, so as to improve the stability and load-bearing capacity of the structure, adapt to different bridge construction scenarios, and enhance the applicability and practicability of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of an optimized structure of the stress of the diaphragm plate at the turning point of the bottom plate of a steel box girder according to an embodiment of the present invention;

[0028] Figure 2 It is a schematic structural diagram of the turning point of an optimized structure of the stress of the diaphragm plate at the turning point of the bottom plate of a steel box girder according to an embodiment of the present invention;

[0029] Figure 3Schematic diagram of the structure at the turning point of the transverse diaphragm at the turning point of the steel box girder bottom plate in an embodiment of the present invention;

[0030] Figure 4 Schematic flow chart of the construction method of the optimized structure of the transverse diaphragm stress at the turning point of the steel box girder bottom plate in an embodiment of the present invention.

[0031] In all the drawings, the same reference numerals represent the same technical features, specifically: 1 - top plate, 2 - bottom plate, 3 - inclined bottom plate, 4 - stiffening rib, 5 - side web, 6 - transverse diaphragm, 7 - middle web, 8 - corner stiffening plate, 9 - air nozzle. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

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

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions conflicts with each other or cannot be realized, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0035] In this patent, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the presence of additional identical elements in the process, method, article or device comprising the said elements.

[0036] Example 1

[0037] like Figures 1 - 3 As shown, an embodiment of the present invention provides an optimized structure for the stress of the diaphragm at the turning point of the bottom plate of a steel box girder, comprising a top plate 1 arranged at the bottom of the bridge deck, a bottom plate 2 is arranged at the bottom of the top plate 1, both ends of the main body of the bottom plate 2 are turned upward to form a turning part, and the turning part and the bottom plate main body together constitute the bottom plate 2, a plurality of middle web plates 7 extending along the longitudinal direction of the bridge are arranged between the top plate 1 and the bottom plate 2, an inclined bottom plate 3 is fixedly installed at both ends of the turning part of the bottom plate 2, and the angle between the bottom plate 2 and the inclined bottom plate 3 is an obtuse angle, and the A side web 5 is fixedly installed between the inclined bottom plate 3 and the top plate 1. The top plate 1, the bottom plate 2, the inclined bottom plate 3 and the side web 5 together form a cavity. A plurality of transverse partitions 6 are arranged at intervals along the longitudinal direction of the cavity. The transverse partitions 6 are fixedly connected to the top plate 1, the bottom plate 2, the inclined bottom plate 3 and the inner side of the side web 5. A plurality of stiffening ribs 4 arranged at intervals are arranged inside the top plate 1, the bottom plate 2, the inclined bottom plate 3 and the side web 5. Wind nozzles 9 are fixedly installed on the outer side of the side web 5 at both ends of the transverse direction of the cavity. The top plate 1, the bottom plate 2, the inclined bottom plate 3 and the side web 5 together form a closed cavity structure, which can significantly improve the bearing capacity of the bridge. The top plate 1 bears the upper load, the bottom plate 2 provides support and enhances the structural stability, and the inclined bottom plate 3 and the side web 5 play the role of connecting and transferring loads. The provision of the diaphragm 6 and the stiffening ribs 4 further enhances the integrity and rigidity of the structure, allowing the bridge to better withstand various loads. The two ends of the main body of the bottom plate 1 turn upward to form a turning part, which together with the main body of the bottom plate 2 constitute a complete bottom plate structure, which can enhance the torsional rigidity of the bottom plate 2 and improve the stability of the bridge. The provision of the wind nozzle 9 helps to reduce wind resistance, reduce the impact of wind loads on the bridge, and further improve the stability of the bridge. The provision of the diaphragm 6 helps to 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 diaphragm provided at the support can disperse the support reaction force and reduce the impact of local loads on the structure. The provision of the stiffening ribs 4 enhances the local rigidity of the diaphragm 6 and adjacent plates, and improves the structure's resistance to local loads.

[0038] Corner stiffening plates 8 are provided on both sides of the intersection of the turning point of the base plate 2 and the diaphragm 6. The corner stiffening plates 8 are perpendicular to the diaphragm 6. The setting of the corner stiffening plates 8 increases the local stiffness of the intersection of the turning point of the base plate 2 and the diaphragm 6, so that this area can better withstand the load from the upper part and the surrounding area of ​​the bridge. By being set perpendicular to the diaphragm 6, the corner stiffening plates 8 can more effectively transfer and disperse the load, avoid excessive stress concentration at the turning point, thereby enhancing the strength and stability of the overall structure. The corner stiffening plates 8 can reduce structural damage and fatigue damage caused by stress concentration, make the structural force more reasonable and uniform, and extend the service life of the bridge.

[0039] Furthermore, the stiffener 4 includes, but is not limited to, closed and open structural forms. Due to its closed structural characteristics, the closed stiffener has higher torsional stiffness and load-bearing capacity, and is particularly suitable for situations that need to withstand large lateral or torsional loads. Its cross-sectional shape can be designed as rectangular, circular, elliptical, etc., depending on the force analysis and design requirements. The closed stiffener can also effectively prevent moisture intrusion, reduce the corrosion risk, and extend the service life of the structure; the open stiffener is characterized by its light weight, easy processing, and high cost-effectiveness, and is suitable for scenarios with relatively small loads or strict requirements for material weight. The cross-sectional form of the open stiffener can be angle steel, channel steel, etc., and its opening direction can be optimized according to the force direction to improve the material utilization efficiency; the most suitable structural form can be selected according to the specific force conditions and design requirements, so as to improve the stability and load-bearing capacity of the structure.

[0040] Furthermore, the diaphragm 6 includes, but is not limited to, solid-web and open-web structural forms. The connection method between the inclined bottom plate 3 and the turning part of the bottom plate 2 is welding or connection with pre-tightening parts. By adopting different forms of stiffeners 4 (closed or open) and diaphragms 6 (solid-web or open-web), the solid-web diaphragm is known for its good integrity, high stiffness, and strong load-bearing capacity, and is suitable for situations that need to withstand large vertical and horizontal loads. The solid-web diaphragm is usually designed as rectangular or circular, and its size and thickness need to be calculated and determined according to the specific force conditions; the open-web diaphragm adopts an open-web structure, realizing a lightweight design while ensuring a certain load-bearing capacity, and is suitable for situations with strict requirements for the self-weight of the structure, such as long-span bridges. The open-web diaphragm can also be locally strengthened according to the force needs to improve its load-bearing capacity; the most suitable structural form can be selected according to the specific force conditions and design requirements, so as to improve the stability and load-bearing capacity of the structure.

[0041] Furthermore, the corner stiffening plate 8 is connected to the bottom plate 2 and the diaphragm 6 by welding, and the corner stiffening plate 8 evenly distributes the obtuse angle at the bending of the bottom plate 2, not only optimizing the stress distribution, reducing the generation of high-stress areas, improving the overall load-bearing capacity and durability of the structure, but also effectively reducing the stress concentration at the corner of the diaphragm at the bending of the bottom plate by dispersing the stress, thereby extending the service life of the structure and reducing the 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 into a single piece. A hole in the shape of the corner stiffening plate 8 is opened on the diaphragm 6, and the corner stiffening plate 8 is passed through the hole and welded to the turning point of the bottom plate 2 and the diaphragm 6. As a single piece, the corner stiffening plate 8 can better coordinate the force transfer at the turning point of the diaphragm 6 and the bottom plate 2 compared with the traditional multi-piece splicing method, significantly enhancing the integrity of the entire structure and effectively resisting various complex external forces. Only a hole with a specific shape needs to be opened on 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 the construction difficulty and labor cost. At the same time, the installation accuracy of a single-piece corner stiffening plate 8 is easier to control, which helps to improve the overall construction quality and efficiency, shorten the construction period. Especially for large-scale engineering projects, it can effectively save time and resource costs.

[0043] Embodiment 2

[0044] As Figure 3 shown, the embodiment of the present invention provides another optimized structure for the stress of the diaphragm at the turning point of the steel box girder bottom plate. In this embodiment, other contents are the same as those in Embodiment 1. The difference from Embodiment 1 is only that both ends of the main body of the bottom plate 2 are turned upward twice to form two turning parts, and the two turning parts and the bottom plate main body together form the bottom plate 2. 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 distance 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 points at both ends near the turning part of the bottom plate 2.

[0045] When the bottom plate 2 and the inclined bottom plate 3 are under tension and the forces are synthesized, the resultant force will act on the stiffening rib 4, and the stiffening rib 4 will transfer the resultant force to a farther position of the diaphragm. Thereby, the stress at the corner of the diaphragm at the bottom plate bending part is greatly reduced, the stress distribution of the diaphragm can be effectively optimized, and the high-stress area can be reduced, thus improving the safety and durability of the structure. The setting of the stiffening rib 4 enhances the local stability at the turning point of the bottom plate, preventing structural deformation or damage caused by stress concentration. Setting the stiffening rib 4 directly at the turning point of the bottom plate hardly increases the cost and improves the construction convenience.

[0046] Furthermore, the stiffening ribs 4 provided at the turning point of the bottom plate 2 are specially manufactured to match the stiffening ribs 4 according to the needs, and the thickness and size of the stiffening ribs 4 are adjusted according to the stress conditions; according to the force analysis results, the thickness of the stiffening ribs can be partially or completely adjusted, and in the stress concentration area, the thickness can be appropriately increased to improve the bearing capacity; in the stress area, the thickness can be appropriately reduced to reduce the weight. By adjusting the stiffening ribs 4 at the turning point, the bearing capacity and stress distribution performance of the place can be improved, the local stability of the structure can be improved, and the stress concentration can be reduced to adapt to different engineering needs, which helps to extend 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 rib 4 is a crucial load-bearing element in the bridge structure. Its material properties directly determine the overall mechanical properties, safety and durability of the structure. High-strength and corrosion-resistant steel is selected as the manufacturing material of the stiffening rib 4 to meet the stringent requirements of the structure for strength and durability. The selection of high-strength steel enables the stiffening rib to maintain excellent load-bearing capacity and stability when facing complex and changeable load conditions, and effectively resist the impact of external forces. The use of corrosion-resistant steel ensures that the stiffening rib can maintain the integrity and durability of the structure under harsh natural environments, such as moisture, salt spray and other corrosive conditions, thereby extending the service life of the bridge.

[0048] The material thickness and yield strength of the stiffener 4 also need to be calculated rigorously and accurately. The determination of the material thickness needs to be based on the specific stress conditions of the stiffener in the bridge structure, taking into account various factors such as bending moment, shear force, axial force, etc. Through structural mechanics analysis, it is ensured that the stiffener has sufficient strength and rigidity to resist damage from external forces. The yield strength is related to whether the stiffener will undergo plastic deformation or fracture under extreme load conditions. Based on the mechanical properties of the material and the safety factor of the structural design, the yield strength is accurately calculated to ensure that the stiffener can remain stable and will not be damaged when subjected to the combined force.

[0049] Example 3

[0050] Combination Figures 1 - 3 ,like Figure 4 As shown, the present invention provides a construction method for optimizing the stress of the diaphragm at the turning point of the bottom plate of a steel box beam, comprising the following steps:

[0051] S100: Prefabricate the steel box girder in stages according to the design drawings, select steel materials that meet the standards, cut and shape the top plate 1, bottom plate 2, inclined bottom plate 3, stiffening ribs 4, side webs 5, diaphragms 6, and middle webs 7, and perform necessary surface treatment on all components to ensure welding quality;

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

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

[0054] S300: If additional corner stiffening plates 8 are used to improve the stress concentration at the turning point of the diaphragm 6 on the bottom plate 2, weld the corner stiffening plates 8 to the turning point of the diaphragm 6 and the bottom plate 2;

[0055] According to the stress distribution at the turning point of the diaphragm 6 on the bottom plate 2, design the appropriate shape, size, and thickness of the corner stiffening plates 8. Place the corner stiffening plates 8 accurately at the predetermined positions at the turning point of the diaphragm 6 and the bottom plate 2, and use positioning jigs or tooling to fix them. Weld the corner stiffening plates 8 to the turning point of the diaphragm 6 and the bottom plate 2. During the welding process, strictly control the welding deformation and weld quality.

[0056] S400: If measures are taken to increase the stiffening ribs 4 to improve the stress concentration at the turning point of the diaphragm 6 on 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 distance between the two webs of the closed stiffening rib, and the stiffening rib 4 is set 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 set at the turning points at both ends near the turning part of the bottom plate 2;

[0057] According to the stress distribution at the turning point of the diaphragm 6 on the bottom plate 2, design the appropriate size and thickness of the stiffening rib 4. Place the stiffening rib 4 accurately at the predetermined position at the turning point of the bottom plate 2, and use positioning jigs or tooling to fix it. Weld the stiffening rib 4 to the turning point of the bottom plate 2. During the welding process, strictly control the welding deformation and weld quality.

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

[0059] An optimized structure and construction method for the stress of the diaphragm at the turning point of the steel box girder floor slab according to the present invention. By setting corner stiffeners 8 on both sides of the intersection of the turning point of the floor slab 2 and the diaphragm 6 or arranging the stiffening ribs 4 in the floor slab 2 at the turning point of the floor slab 2, the resultant force when the floor slab 2 and the inclined floor slab 3 are subjected to tensile forces and the forces are synthesized is effectively transmitted to a farther position of the diaphragm 6, avoiding excessive stress concentration at the turning point, significantly optimizing the stress distribution of the diaphragm 6, reducing the high-stress area, improving the safety and durability of the structure. The setting of the corner stiffeners 8 or the stiffening ribs 4 increases the local stiffness at the intersection of the turning point of the floor slab 2 and the diaphragm 6, enabling this area to better bear the loads from the upper part and the periphery of the bridge, helping to prevent structural deformation or damage caused by stress concentration, and improving the strength and stability of the overall structure. The connection method of the corner stiffeners 8 with the floor slab 2 and the diaphragm 6 is welding, making the construction more convenient and fast and improving the construction efficiency.

[0060] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An optimized structure for the stress of the diaphragm at the turning point of the bottom plate of a steel box beam, characterized in that: It comprises a top plate (1) arranged at the bottom of a bridge deck, a bottom plate (2) being arranged at the bottom of the top plate (1), two ends of a main body of the bottom plate (2) being turned upward to form a turning portion, and the turning portion and the main body of the bottom plate together constitute the bottom plate (2); A plurality of middle webs (7) extending in the longitudinal direction of the bridge are arranged between the top plate (1) and the bottom plate (2); inclined bottom plates (3) are fixedly installed at both ends of the turning part; side webs (5) are fixedly installed between the inclined bottom plate (3) and the top plate (1); the top plate (1), the bottom plate (2), the inclined bottom plate (3) and the side webs (5) together form a cavity; a plurality of transverse diaphragms (6) are arranged at intervals inside the cavity along the longitudinal direction of the bridge; the transverse diaphragms (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 webs (5); a plurality of stiffening ribs (4) arranged at intervals are arranged on the inner sides of the top plate (1), the bottom plate (2), the inclined bottom plate (3) and the side webs (5); Corner point stiffening plates (8) are provided on both sides of the intersection of the bottom plate (2) and the transverse diaphragm (6); the corner point stiffening plates (8) are perpendicular to the transverse diaphragm (6) and are used to improve the stress concentration of the transverse diaphragm (6) at the turning point of the bottom plate (2), optimize the stress distribution of the transverse diaphragm (6), and reduce the high stress area.

2. The optimized structure of the cross diaphragm stress at the turning point of the bottom plate of the steel box beam according to claim 1 is characterized in that: It also includes two turning parts formed by turning upward twice at both ends of the bottom plate (2) body. When the bottom plate stiffening rib (4) is a closed stiffening rib, the width of the turning part close to the bottom plate (2) matches the spacing between the two webs of the closed stiffening rib, and the stiffening rib (4) is arranged at the turning part 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 parts at both ends of the turning part close to the bottom plate (2).

3. The optimized structure of the cross diaphragm stress at the turning point of the bottom plate of a steel box beam according to claim 1 is characterized in that: The stiffening ribs (4) include but are not limited to closed-type and open-type structural forms.

4. The structure for optimizing the stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to claim 1, characterized in that: The transverse partition (6) includes but is not limited to a solid-belly type and a hollow-belly type structure.

5. An optimized structure for the stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to any one of claims 1 to 4, characterized in that: The inclined bottom plate (3) and the turning portion of the bottom plate (2) are connected by welding or pre-tightening.

6. An optimized structure for stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to any one of claims 1 to 4, characterized in that: The corner stiffening plate (8) is connected to the bottom plate (2) and the transverse partition plate (6) by welding.

7. The structure for optimizing the stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to claim 6, characterized in that: The corner point stiffening plates (8) evenly distribute the obtuse angles at the bends of the bottom plate (2).

8. The structure for optimizing the stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to any one of claim 7, characterized in that: The corner stiffening plates (8) on both sides of the transverse partition (6) are a whole piece, a hole in the shape of the corner stiffening plate (8) is opened on the transverse partition (6), the corner stiffening plate (8) passes through the hole and is welded to the turning point of the bottom plate (2) and the transverse partition (6).

9. An optimized structure for stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to any one of claims 1 to 4, characterized in that: The stiffening ribs (4) arranged at the turning point of the bottom plate (2) are specially manufactured according to the requirements to match the stiffening ribs (4), and the thickness and size of the stiffening ribs (4) are adjusted according to the stress conditions.

10. A construction method for optimizing the stress of the diaphragm at the turning point of the bottom plate of a steel box beam according to any one of claims 1 to 9, characterized in that: The steps include: S100: Prefabricate the steel box girder in stages according to the design drawings, select steel materials that meet the standards, cut and shape the top plate (1), bottom plate (2), inclined bottom plate (3), stiffening ribs (4), side webs (5), diaphragms (6), and middle webs (7), and perform necessary surface treatment on all components to ensure welding quality; S200: welding the top plate (1), the bottom plate (2), the inclined bottom plate (3), the stiffening ribs (4), the side webs (5), the diaphragm (6), and the middle webs (7) in sequence to ensure the welding quality; S300: If a corner stiffening plate (8) is added to improve the stress concentration of the diaphragm (6) at the turning point of the bottom plate (2), the corner stiffening plate (8) is welded to the turning point of the diaphragm (6) and the bottom plate (2); S400: If the measure of adding stiffening ribs (4) is adopted to improve the stress concentration of the diaphragm (6) at the turning point of the bottom plate (2), it is necessary to turn the two ends of the bottom plate (2) upward twice to form two turning parts. When the bottom plate stiffening rib (4) is a closed stiffening rib, the width of the turning part close to the bottom plate (2) matches the distance between the two webs of the closed stiffening rib, and the stiffening rib (4) is arranged at the turning part 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 parts at both ends of the turning part close to the bottom plate (2); S500: The air nozzles (9) are fixedly installed on both sides of the steel box girder.

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