Steel structure fatigue crack reinforcing device and method

Abstract

The invention relates to the technical field of steel structures, in particular to a steel structure fatigue crack reinforcing device and method. The steel structure fatigue crack reinforcing device comprises an upper reinforcing steel plate, a lower reinforcing steel plate, crack end holes and check bolts. The crack end hole is formed in the tail end of the crack on the steel structure; the upper reinforcing steel plate and the lower reinforcing steel plate are fixedly installed on the upper side and the lower side of the steel structure respectively and are of strip-shaped plate structures, and the length direction of the upper reinforcing steel plate and the length direction of the lower reinforcing steel plate are perpendicular to cracks. The anti-loosening bolts are arranged in the penetrating holes and the bolt mounting holes in a penetrating mode and used for locking the upper reinforcing steel plate and the lower reinforcing steel plate on the upper side and the lower side of the steel structure. The method effectively solves the problems of crack propagation and strength reduction, has the advantages of simplicity and convenience in construction, economy, high efficiency, high adaptability and the like, and remarkably improves the safety and prolongs the service life of the steel structure.

Description

Technical Field

[0001] The invention relates to the technical field of steel structures, and in particular to a steel structure fatigue crack reinforcement device and method. Background Art

[0002] Steel structures are widely used in the fields of ships, automobiles, buildings and bridges due to their advantages such as light weight, high strength and good earthquake resistance. However, fatigue cracking is one of the main causes of steel structure failure. According to statistics, 80% to 90% of steel structure failures are related to fatigue fracture. Therefore, maintenance and reinforcement measures must be taken for steel structures with fatigue cracks to ensure safety.

[0003] Common fatigue crack treatment technologies include drilling to stop cracks, optimizing structures, and gluing steel plates or CFRP. Among them, drilling to stop cracks is often used in bridge maintenance because it is simple to operate and economical and efficient. The principle is to improve stress concentration, delay crack propagation, and increase component fatigue life by drilling holes at the front end of the crack. In actual engineering, larger apertures are often used to reduce the stress concentration factor, but studies have shown that drilling to stop cracks has limited effects, especially under out-of-plane deformation or high stress amplitudes, cracks may initiate again, and secondary reinforcement is required.

[0004] In order to improve the effect of drilling crack arrest, the Chinese patent application number 202410593239.8 proposed a cold expansion bolt reinforcement device, which forms a residual compressive stress area by cold expansion treatment at the front end or middle section of the crack, delaying or even preventing the crack from expanding. The permanent reinforcement structure of the cold expansion bolt can also prevent loosening and stress relaxation. However, this method can only delay the crack expansion, and cannot repair the strength reduction problem of the crack that has already occurred.

[0005] Therefore, there is an urgent need for a new type of steel structure fatigue crack reinforcement device and method to provide an effective solution to the defects of the existing technology. Summary of the invention

[0006] The object of the present invention is to provide a steel structure fatigue crack reinforcement device and method to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A fatigue crack reinforcement device for a steel structure, comprising an upper reinforcing steel plate, a lower reinforcing steel plate, a crack end hole and an anti-loosening bolt; the crack end hole is arranged at the end of the crack on the steel structure; the upper reinforcing steel plate and the lower reinforcing steel plate are respectively fixedly mounted on the upper and lower sides of the steel structure, the upper reinforcing steel plate and the lower reinforcing steel plate are strip-shaped plate structures, and the length direction of the upper and lower reinforcing steel plates is perpendicular to the crack; the upper and lower reinforcing steel plates are provided with bolt mounting holes, the steel structure is provided with through holes, the positions of the through holes and the bolt mounting holes coincide, the through holes are evenly distributed on both sides of the crack, the bolt mounting holes are evenly distributed on both sides of the center line of the length direction of the upper and lower reinforcing steel plates, and the anti-loosening bolts are penetrated through the through holes and the bolt mounting holes, and are used to lock the upper and lower reinforcing steel plates to the upper and lower sides of the steel structure.

[0009] Furthermore, the anti-loosening bolt includes a screw, a nut and two pairs of anti-loosening washers, and the two pairs of anti-loosening washers are respectively pressed on the upper surface of the upper reinforcing steel plate and the lower surface of the lower reinforcing steel plate, and the anti-loosening washers include an upper washer and a lower washer, and the lower surface of the upper washer is distributed with lower slope teeth in a ring array, and the upper surface of the lower washer is distributed with upper slope teeth in a ring array, and the upper slope teeth are snap-fitted with the lower slope teeth, and the shape of the upper slope teeth is convex in front and concave in the rotation direction of the screw thread, and the shape of the lower slope teeth is concave in front and convex in the rotation direction of the screw thread, and the tooth surface inclination angles of the upper slope teeth and the lower slope teeth are greater than the helix angle of the screw.

[0010] Furthermore, upper resistance-increasing teeth are distributed in a ring array on the upper surface of the upper gasket, and lower resistance-increasing teeth are distributed in a ring array on the lower surface of the lower gasket.

[0011] Furthermore, reinforcing ribs parallel to the length direction are provided on the upper surface of the upper reinforcing steel plate and on the lower surface of the lower reinforcing steel plate.

[0012] Furthermore, the upper reinforcement steel plate and the lower reinforcement steel plate are wide in the middle and uniformly narrowed at both ends in the length direction.

[0013] Furthermore, the upper reinforcement steel plate and the lower reinforcement steel plate are made of metal material or carbon fiber material.

[0014] A steel structure fatigue crack reinforcement method is applicable to any steel structure fatigue crack reinforcement device described in claims 1-6, comprising the following steps:

[0015] S1. Drill crack end holes at the ends of cracks on the steel structure to prevent further crack expansion;

[0016] S2. Perforations are evenly opened on the steel structure in a direction perpendicular to the cracks, and bolt installation holes are opened in the length direction of the upper reinforcement steel plate and the lower reinforcement steel plate, and the bolt installation holes coincide with the perforation positions;

[0017] S3. Fix the upper reinforcement steel plate and the lower reinforcement steel plate on the upper and lower sides of the steel structure respectively by bolts.

[0018] Furthermore, when there are multiple cracks on the steel structure in S, the placement directions of the upper and lower reinforcing steel plates are determined by a fitting straight line of the multiple cracks, and the length directions of the upper and lower reinforcing steel plates are perpendicular to the fitting straight line.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention improves the stress concentration at the front end of the crack and compensates for the strength reduction problem caused by the crack by setting a crack end hole at the end of the crack and combining the reinforcement effect of the upper reinforcement steel plate and the lower reinforcement steel plate. Compared with the traditional drilling crack arrest method, the device significantly improves the reinforcement effect through comprehensive reinforcement measures, reduces the need for secondary reinforcement, and reduces maintenance costs.

[0021] 2. The present invention effectively prevents the bolt from loosening under frequent vibration or dynamic loads through the self-locking structure of the bevel teeth, significantly improves the reliability of the connection, and reduces the structural safety hazards caused by loosening. Due to the existence of the self-locking function, the bolts do not need to be frequently checked and tightened during long-term use, reducing maintenance costs and workload. The self-locking function ensures the stability of the bolt connection, especially in high vibration or impact environments, and can maintain the firmness of the connection and extend the service life of the structure.

[0022] 3. The present invention improves stress concentration through crack end holes, delays crack expansion, improves overall structural strength and rigidity through upper and lower reinforcement steel plates, and determines the reinforcement direction through fitting straight lines to fully cover multiple cracks. The present invention effectively solves the problems of crack expansion and strength reduction, has the advantages of simple construction, economic efficiency, strong adaptability, etc., and significantly improves the safety and life of steel structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a steel structure fatigue crack reinforcement device;

[0024] Figure 2 It is a schematic diagram of the structural decomposition of a steel structure fatigue crack reinforcement device;

[0025] Figure 3 It is a structural schematic diagram of the steel structure;

[0026] Figure 4 It is a schematic diagram of the structure of the reinforced steel plate;

[0027] Figure 5 It is a structural schematic diagram of the anti-loosening bolt;

[0028] Figure 6It is a structural schematic diagram of the anti-loosening gasket;

[0029] Figure 7 It is a schematic diagram of the structure of the anti-loosening gasket and the screw.

[0030] In the figure: 1. Steel structure; 2. Crack; 3. Crack end hole; 4. Bolt mounting hole; 5. Upper reinforcing steel plate; 6. Reinforcing ribs; 7. Perforation; 8. Lower reinforcing steel plate; 9. Anti-loosening bolt; 10. Screw; 11. Nut; 12. Anti-loosening gasket; 13. Upper gasket; 14. Upper resistance-increasing tooth; 15. Lower slope tooth; 16. Lower gasket; 17. Lower resistance-increasing tooth; 18. Upper slope tooth; 19. Tooth surface inclination angle; 20. Helix angle. DETAILED DESCRIPTION

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

[0032] Example 1: Please refer to Figures 1 to 7 , a steel structure fatigue crack reinforcement device, comprising an upper reinforcing steel plate 5, a lower reinforcing steel plate 8, a crack end hole 3 and an anti-loosening bolt 9; the crack end hole 3 is arranged at the end of the crack 2 on the steel structure 1; the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 are fixedly installed on the upper and lower sides of the steel structure 1 respectively, the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 are strip-shaped plate structures, and the length direction of the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 is perpendicular to the crack 2; the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 are provided with bolt mounting holes 4, and the steel structure 1 is provided with through holes 7, the positions of the through holes 7 and the bolt mounting holes 4 coincide, the through holes 7 are evenly distributed on both sides of the crack 2, the bolt mounting holes 4 are evenly distributed on both sides of the center lines of the length directions of the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8, and the anti-loosening bolts 9 are penetrated in the through holes 7 and the bolt mounting holes 4, and are used to lock the upper and lower reinforcing steel plates 5 and the lower reinforcing steel plates 8 on the upper and lower sides of the steel structure 1.

[0033] Reinforcement ribs 6 parallel to the length direction are provided on the upper surface of the upper reinforcing steel plate 5 and on the lower surface of the lower reinforcing steel plate 8 .

[0034] The upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 are wide in the middle and uniformly narrow at both ends in the length direction.

[0035] The upper reinforcement steel plate 5 and the lower reinforcement steel plate 8 are made of metal material or carbon fiber material.

[0036] Working principle of this embodiment:

[0037] In this embodiment, a crack end hole 3 is set at the end of the crack 2 on the steel structure 1, and the stress concentration at the front end of the crack is improved by drilling to stop the crack, thereby delaying the crack extension. The upper reinforcement steel plate 5 and the lower reinforcement steel plate 8 are respectively installed on the upper and lower sides of the steel structure 1, and the length direction is perpendicular to the crack 2. The reinforcement steel plate is aligned with the through hole 7 on the steel structure 1 through the bolt installation hole 4, and the anti-loosening bolt 9 passes through these holes to firmly fix the reinforcement steel plate on the steel structure.

[0038] The upper surface of the upper reinforcement steel plate 5 and the lower surface of the lower reinforcement steel plate 8 are provided with reinforcing ribs 6 parallel to the length direction, which further enhance the rigidity and bending resistance of the reinforcement steel plates and improve the stability of the overall structure. The design of the upper reinforcement steel plate 5 and the lower reinforcement steel plate 8 being wide in the middle and uniformly narrowed at both ends makes the stress distribution more uniform and reduces the stress concentration phenomenon.

[0039] The upper reinforcement steel plate 5 and the lower reinforcement steel plate 8 can be made of metal material or carbon fiber material. Suitable materials are selected according to specific engineering requirements to achieve the best reinforcement effect.

[0040] This embodiment improves the stress concentration at the front end of the crack and compensates for the strength reduction problem caused by the crack by setting the crack end hole 3 at the end of the crack and combining the reinforcement effect of the upper reinforcement steel plate 5 and the lower reinforcement steel plate 8. Compared with the traditional drilling crack arrest method, the device significantly improves the reinforcement effect through comprehensive reinforcement measures, reduces the need for secondary reinforcement, and reduces maintenance costs.

[0041] Example 2: Please refer to Figures 5 to 7 , a steel structure fatigue crack reinforcement device and method, which is different from Example 1 in that the anti-loosening bolt 9 includes a screw 10, a nut 11 and two pairs of anti-loosening washers 12, and the two pairs of anti-loosening washers 12 are respectively pressed on the upper surface of the upper reinforcement steel plate 5 and the lower surface of the lower reinforcement steel plate 8, and the anti-loosening washers 12 include an upper washer 13 and a lower washer 16. The lower surface of the upper washer 13 is provided with lower slope teeth 15 in an annular array, and the upper surface of the lower washer 16 is provided with upper slope teeth 18 in an annular array. The upper slope teeth 18 are snap-fitted with the lower slope teeth 15. The shape of the upper slope teeth 18 is convex in front and concave in the direction of rotation of the screw thread 10, and the shape of the lower slope teeth 15 is concave in front and convex in the direction of rotation of the screw thread 10. The tooth surface inclination angle 19 of the upper slope teeth 18 and the lower slope teeth 15 is greater than the helix angle 20 of the screw 10.

[0042] Upper resistance-increasing teeth 14 are distributed in an annular array on the upper surface of the upper gasket 13 , and lower resistance-increasing teeth 17 are distributed in an annular array on the lower surface of the lower gasket 16 .

[0043] In this embodiment, the upper bevel teeth 18 and the lower bevel teeth 15 are engaged with each other through a tooth shape design of convex in front and concave in the back and concave in front and convex in the back. This structure forms a one-way locking mechanism in the direction of thread rotation of the screw 10. The tooth surface inclination angle 19 of the bevel teeth 18 and the lower bevel teeth 15 is greater than the helix angle 20 of the screw 10. This design enables the bevel teeth to be tightly engaged during the tightening of the bolt to form a self-locking effect. When the bolt is subjected to vibration or external load, the bite of the bevel teeth will prevent the nut 11 from rotating in the opposite direction, thereby avoiding loosening. Due to the self-locking effect of the bevel teeth, a torque greater than the self-locking force needs to be applied during disassembly to overcome the bite resistance of the bevel teeth, so that the upper bevel teeth 18 are separated from the lower bevel teeth 15, thereby realizing the disassembly of the bolt. The upper surface of the upper gasket 13 is provided with upper resistance-increasing teeth 14 in an annular array, and the lower surface of the lower gasket 16 is provided with lower resistance-increasing teeth 17 in an annular array. These friction-enhancing teeth increase the friction between the gasket and the reinforcement plate, further preventing the bolts from loosening.

[0044] This embodiment effectively prevents the bolt from loosening under frequent vibration or dynamic loads through the self-locking structure of the bevel teeth, significantly improves the reliability of the connection, and reduces the structural safety hazards caused by loosening. Due to the existence of the self-locking function, the bolts do not need to be frequently checked and tightened during long-term use, reducing maintenance costs and workload. The self-locking function ensures the stability of the bolt connection, especially in high vibration or impact environments, and can maintain the firmness of the connection and extend the service life of the structure.

[0045] Example 3: Please refer to Figures 1 to 7 A steel structure fatigue crack reinforcement method is applicable to any steel structure fatigue crack reinforcement device of claims 1-6, comprising the following steps:

[0046] S1. Drill a crack end hole 3 at the end of the crack 2 on the steel structure 1 to prevent the crack from further expanding;

[0047] S2. Perforations 7 are evenly opened on the steel structure 1 in a direction perpendicular to the crack 2, and bolt mounting holes 4 are opened in the length direction of the upper reinforcement steel plate 5 and the lower reinforcement steel plate 8, and the bolt mounting holes 4 coincide with the positions of the perforations 7;

[0048] S3. Fix the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 on the upper and lower sides of the steel structure 1 respectively by bolts.

[0049] When there are multiple cracks 2 on the steel structure 1 in S1, the placement direction of the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 is determined by the fitting straight line of the multiple cracks 2, and the length direction of the upper reinforcing steel plate 5 and the lower reinforcing steel plate 8 is perpendicular to the fitting straight line.

[0050] This embodiment improves stress concentration through the crack end hole 3, delays crack extension S1, improves overall structural strength and stiffness S3 after fixing the upper and lower reinforcing steel plates 5 and 8, and comprehensively covers multiple cracks by determining the reinforcement direction through fitting straight lines. This embodiment effectively solves the problems of crack extension and strength reduction through the comprehensive application of crack end holes and reinforcing steel plates, has the advantages of simple construction, economic efficiency, strong adaptability, etc., and significantly improves the safety and life of the steel structure.

Claims

1. A steel structure fatigue crack reinforcement device, characterized in that: It comprises an upper reinforcing steel plate (5), a lower reinforcing steel plate (8), a crack end hole (3) and an anti-loosening bolt (9); The crack end hole (3) is arranged at the end of the crack (2) on the steel structure (1); The upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) are respectively fixedly mounted on the upper and lower sides of the steel structure (1); the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) are strip-shaped plate structures; and the length directions of the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) are perpendicular to the crack (2); The upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) are provided with bolt mounting holes (4), and the steel structure (1) is provided with through holes (7). The positions of the through holes (7) and the bolt mounting holes (4) coincide with each other. The through holes (7) are evenly distributed on both sides of the crack (2). The bolt mounting holes (4) are evenly distributed on both sides of the lengthwise center lines of the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8). The anti-loosening bolts (9) are inserted into the through holes (7) and the bolt mounting holes (4) to lock the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) on the upper and lower sides of the steel structure (1).

2. A steel structure fatigue crack reinforcement device according to claim 1, characterized in that: The anti-loosening bolt (9) comprises a screw rod (10), a nut (11) and two pairs of anti-loosening washers (12). The two pairs of anti-loosening washers (12) are respectively pressed on the upper surface of the upper reinforcing steel plate (5) and the lower surface of the lower reinforcing steel plate (8). The anti-loosening washers (12) comprise an upper washer (13) and a lower washer (16). The lower surface of the upper washer (13) is provided with lower slope teeth (15) in an annular array. The upper surface of the lower washer (16) is provided with lower slope teeth (15). An annular array of upper slope teeth (18) is distributed on the surface, and the upper slope teeth (18) are engaged with the lower slope teeth (15). The shape of the upper slope teeth (18) is convex in front and concave in the rear in the direction of rotation of the screw thread (10), and the shape of the lower slope teeth (15) is concave in front and convex in the rear in the direction of rotation of the screw thread (10). The tooth surface inclination angle (19) of the upper slope teeth (18) and the lower slope teeth (15) is greater than the helix angle (20) of the screw (10).

3. A steel structure fatigue crack reinforcement device according to claim 2, characterized in that: Upper resistance-increasing teeth (14) are distributed in a ring array on the upper surface of the upper gasket (13), and lower resistance-increasing teeth (17) are distributed in a ring array on the lower surface of the lower gasket (16).

4. A steel structure fatigue crack reinforcement device according to claim 1, characterized in that: Reinforcing ribs (6) parallel to the length direction are provided on the upper surface of the upper reinforcing steel plate (5) and on the lower surface of the lower reinforcing steel plate (8).

5. A steel structure fatigue crack reinforcement device according to claim 1, characterized in that: The upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) are wide in the middle and uniformly narrow at both ends in the length direction.

6. A steel structure fatigue crack reinforcement device according to claim 1, characterized in that: The upper reinforcement steel plate (5) and the lower reinforcement steel plate (8) are made of metal material or carbon fiber material.

7. A steel structure fatigue crack reinforcement method applicable to any steel structure fatigue crack reinforcement device according to claims 1-6, characterized in that: The steps include: S1. Drilling a crack end hole (3) at the end of a crack (2) on a steel structure (1) to prevent the crack from further expanding; S2. Perforations (7) are uniformly provided on the steel structure (1) in a direction perpendicular to the crack (2), and bolt mounting holes (4) are provided in the length direction of the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8), and the bolt mounting holes (4) and the perforations (7) are overlapped in position; S3. The upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) are respectively fixedly mounted on the upper and lower sides of the steel structure (1) by means of bolts.

8. A steel structure fatigue crack reinforcement method according to claim 7, characterized in that: When there are multiple cracks (2) on the steel structure (1) in S1, the placement direction of the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) is determined by a fitting straight line of the multiple cracks (2), and the length direction of the upper reinforcing steel plate (5) and the lower reinforcing steel plate (8) is perpendicular to the fitting straight line.

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