Steel box girder structure and method for repairing weld cracking of steel box girder

Abstract

The present invention relates to the technical field of steel box girders, and particularly to a steel box girder structure and a method for repairing weld cracking of a steel box girder. The steel box girder structure includes a steel box girder assembly and a longitudinal reinforcement assembly. The steel box girder assembly includes a deck plate and U-shaped ribs. The open ends of the U-shaped ribs are connected to the bottom surface of the deck plate to form a cross-section of an annular closed structure. The longitudinal reinforcement assembly is pasted on the deck plate and the U-shaped ribs to cover the weld where the deck plate and the U-shaped ribs are connected. Under the condition that there are many limited conditions for the maintenance of steel box girders in the prior art, the longitudinal reinforcement assembly is pasted to the fatigue cracking part of the steel box girder, providing other feasible solutions in addition to welding and bolting, playing a role in structural reinforcement, improving the bearing capacity and restricting the development of cracks, and achieving the maintenance effect of sustainable maintenance, non-destructive maintenance and minimizing the impact on traffic as much as possible.

Description

Technical Field

[0001] The present invention relates to the technical field of steel box girders, and particularly to a steel box girder structure and a method for repairing weld cracking of a steel box girder. Background Art

[0002] The steel box girder structure is composed of a series of components such as a top plate, a bottom plate, webs, longitudinal stiffeners, transverse stiffeners, and vertical stiffeners, and each component can be connected by a welding process. Due to the large number of welding parts of the steel box girder and the complex stress, and the steel box girder is always under the repeated action of wheel loads. In addition, there are many uncertain factors in the welding process, and there may also be a series of influences such as welding residual stress at the weld. The weld of the steel box girder often becomes the part where cracks are most likely to appear and the cracks develop relatively fast. On the other hand, the large traffic flow and heavy load traffic also exacerbate the generation and development of fatigue cracking of the steel box girder. Especially, the heavy traffic volume that plays a leading role in fatigue damage has increased significantly, resulting in bridges using the steel box girder cross-section form becoming a disaster area for steel fatigue cracking.

[0003] The treatment of weld cracking between the deck plate and the U-rib has always been the key and difficult point in the maintenance of steel box girders. Limited by the characteristics of large traffic flow and heavy load traffic of in-service bridges, in the treatment of corresponding fatigue cracks, it is impossible to carry out maintenance treatment operations by means of interrupting traffic for a long time or affecting traffic. Reducing the traffic impact has become an important factor in controlling the selection of feasible solutions. For the treatment of this type of crack, the conventional typical repair methods (crack welding method, bolt-connected reinforcing steel plate method, combined bridge deck paving reconstruction method) are limited in the implementation of maintenance.

[0004] 1) The welding method is to use the welding method to re-weld the cracked part together after treating the cracked crack. Since welding is repeated at the same position, the heat-affected zone will expand, and the non-uniform heating in the repaired welding area causes a certain degree of composition segregation and structural stress, resulting in different mechanical properties and microstructures between the repaired welding area and the non-repaired welding area, affecting the welding quality. According to relevant research results, repeated welding will cause a decrease in tensile strength and elongation. In addition to the damage of the above process, the construction quality is also difficult to guarantee. On the one hand, the construction quality of overhead welding for maintenance inside the box is difficult to ensure, and the penetration non-compliance rate and construction defects will exceed the in-factory processing. On the other hand, without interrupting traffic, the vibration of the bridge deck will also have a serious impact on the welding construction.

[0005] 2) The bolt-connected reinforcing steel plate is to reinforce across the crack at the crack development position by bolt connection, playing a role of alternative reinforcement. This method requires drilling holes at the corresponding positions of the U-rib and the top plate, which will cause local weakening of the existing steel structure. At the same time, there will be stress concentration problems at the bolt holes. Among them, the bolt connection of the top plate requires breaking the paving in the corresponding area of the top plate, resulting in the interruption of traffic. The protruding bolt head will cause local occupation in the paving layer, resulting in a weak link in the paving stress.

[0006] 3) The combined bridge deck pavement reconstruction method replaces the existing pavement with ultra-high performance concrete pavement to increase the pavement stiffness and reduce the steel plate stress, thereby controlling the development of subsequent cracks. This method requires demolishing the existing pavement and also needs to consider the compatibility between the adopted ultra-high performance concrete pavement system and the original system. The same requirement of long-term traffic closure also restricts the selection of this method. Summary of the Invention

[0007] (1) Technical problems to be solved

[0008] The technical problem to be solved by the present invention is the problem that the existing steel box girder structure is difficult to repair when the weld cracks and the repair process is limited.

[0009] (2) Technical solutions

[0010] To solve the above technical problems, the present invention provides a steel box girder structure, including a steel box girder component and a longitudinal reinforcement component. The steel box girder component includes a deck plate and U ribs. The open ends of the U ribs are connected to the bottom surface of the deck plate to form a cross-section of a circular closed structure. The longitudinal reinforcement component is pasted on the deck plate and the U ribs to cover the weld where the deck plate and the U ribs are connected.

[0011] Wherein, the longitudinal reinforcement component extends along the length direction of the steel box girder component.

[0012] Wherein, the longitudinal reinforcement component includes two reinforcement members symmetrically arranged on both sides of the U rib. One end of the reinforcement member is pasted on the bottom surface of the deck plate, and the other end is pasted on the outer surface of the web of the U rib.

[0013] Wherein, it further includes at least one transverse reinforcement component. The transverse reinforcement component is perpendicular to the deck plate. The transverse reinforcement component is pasted at the weld of the deck plate and the U rib and surrounds the U rib in the cross-section of the steel box girder component.

[0014] Wherein, each transverse reinforcement component is arranged along the width direction of the steel box girder component, and a plurality of transverse reinforcement components are sequentially distributed along the length direction of the steel box girder component.

[0015] Wherein, the transverse reinforcement component is provided with a first flange plate and a second flange plate. The first flange plate is pasted on the bottom surface of the deck plate, and the second flange plate is pasted on the outer surface of the web of the U rib.

[0016] Wherein, the transverse reinforcement component includes a plurality of pairs of sub-transverse reinforcement members. Each pair of sub-transverse reinforcement members is oppositely arranged and joined together to surround a U rib.

[0017] Among them, two adjacent pairs of the sub-horizontal reinforcement members are connected by fasteners.

[0018] The present invention also provides a method for repairing the weld cracking of a steel box girder, including:

[0019] Along the width direction of the steel box girder, a transverse reinforcement assembly surrounding the U-rib is pasted at the weld between the deck plate and the U-rib;

[0020] Along the length direction of the steel box girder, a longitudinal reinforcement assembly covering the weld connecting the deck plate and the U-rib is pasted on the deck plate and the U-rib.

[0021] Among them, at both ends of the crack formed by the weld cracking between the deck plate and the U-rib, holes are drilled downward along the thickness direction of the steel box girder bridge.

[0022] (III) Beneficial effects

[0023] The above technical solutions of the present invention have the following advantages:

[0024] In the steel box girder structure of the embodiment of the present invention, a longitudinal reinforcement assembly is added at the welded joint between the deck plate and the rib plate. The longitudinal reinforcement assembly and the original structure are pasted. That is, the method of pasting reinforcement members is used to repair the cracking of the deck plate-U-rib fillet weld of the steel box girder without damage. The pasted reinforcement member connects the high-strength material and the structure to be reinforced by using a high-performance structural adhesive. The plane force transmission form of the overall structure after pasting replaces the concentrated force transmission form of traditional welding or bolting, relieves the stress concentration condition, and at the same time ensures non-destructive treatment of the part to be repaired. On the other hand, the pasted longitudinal reinforcement assembly can be easily disassembled, leaving the possibility for other possible alternative treatment solutions in the future. Under the condition that there are many limited conditions for the maintenance of steel box girders in the prior art, the longitudinal reinforcement assembly is pasted to the fatigue cracking part of the steel box girder, providing other feasible solutions in addition to welding and bolting, playing a role in structural reinforcement, improving the bearing capacity and restricting the development of cracks, and achieving the maintenance effect of sustainable maintenance, non-destructive maintenance and minimizing the impact on traffic as much as possible.

[0025] The thickness and length of the steel plate of the longitudinal reinforcement assembly are determined according to the force requirements. The first purpose is to directly transmit the deck load to the U-rib through the transverse support of the longitudinal reinforcement assembly under the vehicle load acting in the cross-section direction of the steel box girder assembly, improve the stress condition of the weld between the deck plate and the U-rib, and ensure that the original force system does not change greatly; the second purpose is to exert the stiffness effect of the longitudinal reinforcement assembly to replace and reinforce the stiffness at the crack. Through the method of bonding steel plates for reinforcement, the deformation of the deck plate and the stress of the U-rib can be effectively reduced. Under the same loading conditions, compared with the original structure state, under the simulated wheel loading condition, the deformation of the deck plate can be reduced by 19% and the stress of the U-rib can be reduced by 15%. If the bonding of the steel plate is reliable, it can play a good role in structural reinforcement and delaying fatigue development.

[0026] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted, and the advantages brought by these technical features of the technical solutions described above, other technical features of the present invention and the advantages brought by these technical features will be further described in conjunction with the accompanying drawings. Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of the steel box girder structure of the embodiment of the present invention with a longitudinal reinforcement assembly;

[0028] Figure 2 is a schematic structural diagram of the steel box girder structure of the embodiment of the present invention with a transverse reinforcement assembly;

[0029] Figure 3 is a schematic structural diagram of drilling when repairing the weld cracking of the steel box girder bridge in the embodiment of the present invention.

[0030] 1: Steel box girder assembly; 11: Bridge deck; 12: U-rib;

[0031] 2: Longitudinal reinforcement assembly; 21: Reinforcement member;

[0032] 3: Transverse reinforcement assembly; 31: First flange; 32: Second flange; 33: Sub-transverse reinforcement member;

[0033] 4: Fastener;

[0034] 5: Crack;

[0035] 6: Drill hole. Detailed Embodiments

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In addition, in the description of the present invention, unless otherwise specified, the meanings of "multiple", "multiple roots", and "multiple groups" are two or more, and the meanings of "several", "several roots", and "several groups" are one or more.

[0039] As Figure 1 shown, the steel box girder structure provided by the embodiment of the present invention includes a steel box girder assembly 1 and a longitudinal reinforcement assembly 2. The steel box girder assembly 1 includes a bridge deck 11 and U ribs 12. The open ends of the U ribs 12 are connected to the bottom surface of the bridge deck 11 to form a cross-section of an annular closed structure. The longitudinal reinforcement assembly 2 is pasted on the bridge deck 11 and the U ribs 12 to cover the weld where the bridge deck 11 and the U ribs 12 are connected.

[0040] In the steel box girder structure of the embodiment of the present invention, a longitudinal reinforcement assembly 2 is added at the welded joint of the bridge deck 11 and the rib plate. The longitudinal reinforcement assembly 2 and the original structure are pasted together, that is, the high-strength materials are connected to the structure to be reinforced by using a high-performance structural adhesive. The plane force transmission form of the overall structure after pasting replaces the concentrated force transmission form of traditional welding or bolting, relieves the stress concentration condition, and at the same time ensures that the part to be repaired is treated without damage. On the other hand, the longitudinally pasted reinforcement assembly 2 can be easily disassembled, leaving room for possible other alternative treatment schemes in the future. In the case where there are many restricted conditions for the maintenance of steel box girders in the prior art, the longitudinal reinforcement assembly 2 is pasted to the fatigue cracking position of the steel box girder, providing other feasible solutions in addition to welding and bolting, playing a role in structural reinforcement, improving the bearing capacity and restricting the development of cracks, and achieving the maintenance effect of sustainable maintenance, non-destructive maintenance and minimizing the impact on traffic as much as possible.

[0041] The steel plate thickness and length of the longitudinal reinforcement assembly 2 are determined according to the force requirements. The first purpose is to directly transmit the bridge deck load to the U ribs 12 under the action of the vehicle load in the cross-section direction of the steel box girder assembly 1 by using the transverse support effect of the longitudinal reinforcement assembly 2, improving the stress condition of the weld between the bridge deck 11 and the U ribs 12, and ensuring that the original force system does not change significantly; the second purpose is to exert the stiffness effect of the longitudinal reinforcement assembly 2 to replace and reinforce the stiffness at the crack. By the method of bonding steel plates for reinforcement, the deformation of the bridge deck 11 and the stress of the U ribs 12 can be effectively reduced. Under the same loading conditions, compared with the original structure state, under the simulated wheel loading condition, the deformation of the bridge deck 11 can be reduced by 19% and the stress of the U ribs 12 can be reduced by 15%. When the steel plate bonding is reliable, it can play a good role in structural reinforcement and delaying fatigue development.

[0042] Among them, the longitudinal reinforcement component 2 is arranged along the length direction of the steel box girder component 1. In this embodiment, the cross-section direction of the steel box girder component 1 is the plane formed by the cross-sections of the bridge deck 11 and the U-rib 12, and the length direction of the steel box girder component 1 is perpendicular to the cross-section direction of the steel box girder component 1. Since the weld where the bridge deck 11 is connected to the U-rib 12 is prone to cracking and cracks will appear, the longitudinal reinforcement component 2 is arranged along the length direction of the steel box girder component 1 to cover the crack position, which can strengthen the structural strength of the bridge deck 11 and the U-rib 12, improve the bearing capacity and play a role in restricting the development of cracks.

[0043] Among them, the longitudinal reinforcement component 2 includes two reinforcement members 21 symmetrically arranged on both sides of the U-rib 12. One end of the reinforcement member 21 is pasted on the bottom surface of the bridge deck 11, and the other end is pasted on the outer surface of the web of the U-rib 12. In this embodiment, the reinforcement member 21 of the longitudinal reinforcement component 2 is an arc-shaped bent steel plate, and the steel plate has a bend. The parts on both sides of the bend are respectively pasted on the bottom surface of the bridge deck 11 and the outer surface of the web of the U-rib 12 to connect the bridge deck 11 and the U-rib 12 as the structural reinforcement of the bridge deck 11 and the U-rib 12.

[0044] As Figure 2 shown, the steel box girder structure of the embodiment of the present invention further includes at least one transverse reinforcement component 3. The transverse reinforcement component 3 is perpendicular to the bridge deck 11, the transverse reinforcement component 3 is pasted at the weld of the bridge deck 11 and the U-rib 12, and surrounds the U-rib 12 on the cross-section of the steel box girder component 1. The transverse reinforcement component 3 is also arranged on the bottom surface of the bridge deck 11 and is a structure spanning the U-rib 12 perpendicular to the bridge deck 11, which can change the local stress mode of the steel box girder component 1. The number of pasted transverse reinforcement components 3 is determined according to the force requirement. In this embodiment, after one end of the transverse reinforcement component 3 is pasted on the bridge deck 11 and the U-rib 12, the other end extends towards the closed end of the U-rib 12. The transverse reinforcement components 3 are symmetrically structured on both sides of the U-rib 12 to achieve the enclosure of the U-rib 12. By adding the transverse reinforcement component 3, the local transverse stiffness is strengthened, and together with the longitudinal reinforcement component 2, an orthotropic stress system is formed, which can reduce the deformation of the bridge deck 11 by 52% and the stress of the U-rib 12 by 55%. In the case of reliable steel bonding, it can play a good role in structural reinforcement and delaying fatigue development, and the effect of simultaneous reinforcement of the longitudinal reinforcement component 2 and the transverse reinforcement component 3 is better.

[0045] Among them, each transverse reinforcement component 3 is arranged along the width direction of the steel box girder component 1, and multiple transverse reinforcement components 3 are sequentially distributed along the length direction of the steel box girder component 1. In this embodiment, the cross-section direction of the steel box girder component 1 is the width direction of the steel box girder component 1. A plurality of transverse reinforcement components 3 can be continuously arranged on one cross-section as one transverse reinforcement component 3, and multiple transverse reinforcement components 3 can be continuously arranged in the length direction of the steel box girder to change the local stress mode of the steel box girder structure.

[0046] Among them, a first flange plate 31 and a second flange plate 32 are provided on the transverse reinforcement component 3. The first flange plate 31 is adhered to the bottom surface of the bridge deck 11, and the second flange plate 32 is adhered to the outer surface of the web of the U-rib 12. The transverse reinforcement component 3 fits the bridge deck 11 and the U-rib 12 by using the flange plates formed by extending the end edges thereof, and is connected by a high-performance structural adhesive. The welding seam between the bridge deck 11 and the U-rib 12 is located between the first flange plate 31 and the second flange plate 32. The setting of the flange plates effectively increases the contact area between the transverse reinforcement component 3 and the steel box girder structure, and is more firmly and stably connected after adhesion.

[0047] Among them, the transverse reinforcement component 3 includes multiple pairs of sub-transverse reinforcement members 33. Each pair of sub-transverse reinforcement members 33 is arranged oppositely and joined together to surround a U-rib 12. The transverse reinforcement component 3 can adopt an integral or assembled structure. The integral assembly means that on the cross-section of a steel box girder component 1, the transverse reinforcement component 3 is an integral body and does not need to be assembled, and is integrally disassembled and connected to the steel box girder component 1. In this embodiment, an assembled assembly is provided. Each transverse reinforcement component 3 includes two symmetrical sub-transverse reinforcement members 33. One end of the sub-transverse reinforcement member 33 is adhered to the steel box girder component 1, and the other end extends towards the closed end of the U-rib 12. The groups are joined together by bolting.

[0048] Among them, adjacent pairs of sub-transverse reinforcement members 33 are connected by fasteners 4. In this embodiment, multiple U-ribs 12 are distributed on the cross-section of the same steel box girder component 1. A pair of sub-transverse reinforcement members 33 surrounds the outside of each U-rib 12. To ensure the integrity of the transverse reinforcement component 3 on the same cross-section, as well as to improve the connection strength and structural strength, the transverse reinforcement components 3 are connected by fasteners. In this embodiment, bolts are used as the fasteners and are connected by bolting.

[0049] In this embodiment, the steel plate material, thickness and length of the transverse reinforcement component 3 and the longitudinal reinforcement component 2 are determined according to the crack opening length and the force requirement. The arc-shaped steel plate of the longitudinal reinforcement component 2 is bent by mechanical processing, and the bending radius is as small as possible to meet the requirement of being close to the bridge deck 11 and the U-rib 12. The temperature application range of the high-performance structural adhesive used for adhesion should take into account the requirements of high-temperature special working conditions such as subsequent paving replacement, etc., and at the same time, it is required to have sufficient durability and be applicable to frequent vibration and impact loads. During construction, it is necessary to adopt the method of temporary support to reduce the influence of vibration on the curing of the adhesive, and at the same time, take necessary construction measures to ensure that the thickness of the adhesive layer meets the requirements.

[0050] In the current engineering applications of the present invention, steel is used as the main base material for the reinforcement components. Other similar high-strength and lightweight materials, such as carbon fiber plates, can also be used as the main base materials for processing templates and are substitutable. There are many options for selecting high-performance adhesives, which are also substitutable. The present invention uses high-performance material bonding as the main connection method. Although bolting, welding, etc. have limitations, they can still be used as alternative connection methods.

[0051] The embodiment of the present invention also provides a method for repairing the weld cracking of a steel box girder bridge, including:

[0052] Along the width direction of the steel box girder, a transverse reinforcement component 3 surrounding the U-rib 12 is pasted at the weld between the deck 11 and the U-rib 12;

[0053] Along the length direction of the steel box girder, a longitudinal reinforcement component 2 covering the weld connecting the deck 11 and the U-rib 12 is pasted on the deck 11 and the U-rib 12.

[0054] In the method for repairing the weld cracking of the steel box girder bridge according to the embodiment of the present invention, the longitudinal reinforcement component 2 and the transverse reinforcement component 3 are connected to the steel box girder component by pasting, that is, the angle weld cracking between the deck 11 - U-rib 12 of the steel box girder bridge is repaired without damage by the steel bonding method. Steel bonding uses a high-performance structural adhesive to connect high-strength materials to the structure to be strengthened. The plane force transmission form of the overall structure after pasting replaces the concentrated force transmission form of traditional welding or bolting, relieves the stress concentration condition, and at the same time ensures non-destructive treatment of the part to be repaired. On the other hand, the longitudinal reinforcement component 2 and the transverse reinforcement component 3 after pasting can be easily disassembled, leaving room for possible other alternative treatment solutions in the future. In the case where there are many restricted conditions for the maintenance of steel box girders in the prior art, the longitudinal reinforcement component 2 and the transverse reinforcement component 3 are pasted to the fatigue cracking position of the steel box girder component, providing other feasible solutions in addition to welding and bolting, playing a role in structural reinforcement, improving the bearing capacity and restricting the development of cracks, and achieving the maintenance effect of sustainable maintenance, non-destructive maintenance and minimizing the impact on traffic as much as possible.

[0055] Among them, as Figure 3 shown, at both ends of the crack 5 formed by the weld cracking between the deck 11 and the U-rib 12, holes 6 are drilled downward along the thickness direction of the steel box girder bridge. The crack treatment of the steel box girder component 1 is carried out by combining pasting the transverse reinforcement component 3 in the width direction of the steel box girder component 1, pasting the longitudinal reinforcement component 2 in the length direction of the steel box girder component 1 and crack arrest by drilling. In this embodiment, the direction perpendicular to the deck 11 and the length direction of the steel box girder component 1 is the thickness direction of the steel box girder component 1. After non-destructive testing or hole inspection, according to the detected tip position of the crack 5, holes are drilled to arrest the crack. By the method of crack arrest by drilling, on the one hand, the crack development path is intercepted, and on the other hand, a plastic zone is formed to limit the continuous expansion of the crack towards the plate and the U-rib 12.

[0056] 1) Using ANSYS analysis software, a locally refined analysis model was established. Among them, the deck 11, U-ribs 12, transverse reinforcement components 3, longitudinal reinforcement components 2, etc. were simulated using shell63 elements; the gap between the bonded steel longitudinal reinforcement components 2 and the steel box girder components 1 to be repaired was controlled at 5 mm. The connection was simulated by means of node coupling; the cracking simulation at the weld position was carried out by using the method of birth and death elements. The loading calculation was carried out in accordance with the vehicle load checking standard in the "General Code for Design of Highway Bridges and Culverts" (JTG D60-2015). The wheel load was averaged to the nodes at the loading position and applied as node loads. The deformation of the deck 11 and the Von Mises stress condition of the U-ribs 12 were focused on.

[0057]

[0058] Theoretical calculations show that through the method of bonding steel for reinforcement, both the simplified scheme (only adding longitudinal reinforcement components 2) and the complete scheme (adding longitudinal reinforcement components 2 and transverse reinforcement components 3) can effectively reduce the deformation of the deck 11 and the stress of the U-ribs 12. Under the same loading conditions, compared with the original structural state, in the simulated wheel loading condition, the simplified scheme can reduce the deformation of the deck 11 by 19% and the stress of the U-ribs 12 by 15%; the complete scheme can reduce the deformation of the deck 11 by 52% and the stress of the U-ribs 12 by 55%. It can be considered that under the condition of reliable bonding of steel, the above schemes can play a good role in structural reinforcement and delaying fatigue development, and the complete scheme with simultaneous longitudinal and transverse reinforcement has better effect.

[0059] 2) The effect tracking was carried out on the position after construction. The mechanical evaluation of the effect was carried out from the perspectives of the vibration of the deck 11, the stress of the U-ribs 12, and the relative dislocation of the bonded steel plates. At the same time, the ultrasonic detection method was adopted to make a qualitative judgment on the internal filling fullness.

[0060] After the follow-up monitoring, the monitoring results show that.

[0061] (1) After pasting the steel plates, the vibration of the deck 11 can be effectively controlled. Before pasting the steel plates, under the impact of heavy trucks, the instantaneous maximum acceleration of some parts of the deck 11 could reach 4g, and the vibration was visually visible. After pasting the steel plates, the vibration of the deck 11 was effectively reduced. When different vehicle types passed by, the overall vibration was relatively smooth, and the acceleration amplitude was reduced to less than 2g.

[0062] (2) After pasting the steel plates, the stress of the U-ribs 12 was monitored. From the monitoring results, when different vehicle types passed by, the strain change at the bottom edge of the U-ribs 12 was relatively smooth, and no obvious fluctuations were seen. And the long-term monitoring law was consistent with the overall law of temperature rise and fall.

[0063] (3) By ultrasonic qualitative judgment, the adhesive layer was basically uniformly full.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A steel box girder structure, characterized in that: It includes a steel box girder assembly and orthotropic longitudinal and transverse reinforcement assemblies. The steel box girder assembly includes a bridge deck and U-shaped ribs. The open ends of the U-shaped ribs are connected to the bottom surface of the bridge deck to form a cross-section of a circular closed structure. The longitudinal and transverse reinforcement assemblies are connected to the bridge deck and the U-shaped ribs by pasting reinforcement members. Among them, the longitudinal reinforcement assembly covers the weld cracking position where the bridge deck is connected to the U-shaped ribs. The transverse reinforcement assembly is arranged perpendicular to the bridge deck. The transverse reinforcement assembly is pasted at the weld between the bridge deck and the U-shaped ribs and surrounds the U-shaped ribs in the cross-section of the steel box girder assembly. The transverse reinforcement assembly is symmetrically structured on both sides of the U-shaped ribs. The transverse reinforcement assembly is provided with a first flange and a second flange. The first flange is pasted on the bottom surface of the bridge deck, and the second flange is pasted on the outer surface of the web of the U-shaped rib. The transverse reinforcement assembly includes multiple pairs of sub-transverse reinforcement members. Each pair of the sub-transverse reinforcement members is arranged oppositely and joined together to surround a U-shaped rib. Adjacent pairs of the sub-transverse reinforcement members are connected by fasteners; The steel plate thickness and length of the longitudinal reinforcement assembly are determined according to the force requirements; The number of the pasted transverse reinforcement assemblies is determined according to the force requirements. Each transverse reinforcement assembly is arranged along the width direction of the steel box girder assembly, and multiple transverse reinforcement assemblies are arranged in sequence along the length direction of the steel box girder assembly.

2. The steel box girder structure according to claim 1, characterized in that: The longitudinal and transverse reinforcement assemblies extend orthogonally along the longitudinal and transverse directions of the steel box girder assembly.

3. The steel box girder structure according to claim 1, characterized in that: The longitudinal reinforcement assembly includes two reinforcement members symmetrically arranged on both sides of the U-shaped rib. One end of the reinforcement member is pasted on the bottom surface of the bridge deck, and the other end is pasted on the outer surface of the web of the U-shaped rib.

4. A method for repairing the weld cracking of a steel box girder, which is used in the steel box girder structure described in any one of claims 1-3, and is characterized in that: It includes: Along the width direction of the steel box girder, paste a transverse reinforcement assembly surrounding the U-shaped rib at the weld between the bridge deck and the U-shaped rib; Along the length direction of the steel box girder, paste a longitudinal reinforcement assembly covering the weld where the bridge deck is connected to the U-shaped rib on the bridge deck and the U-shaped rib.

5. The method for repairing the weld crack of the steel box girder according to claim 4, characterized in that: At both ends of the crack formed by the weld cracking between the bridge deck and the U-shaped rib, drill holes downward along the thickness direction of the steel box girder bridge.

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