Prestressed fiber cloth lossless reinforcing device and method for locally reinforcing steel structure

Abstract

The invention discloses a prestressed fiber cloth lossless reinforcing device and method for locally reinforcing a steel structure. The reinforcing device comprises a steel frame, an upper anchor plate, a fixing shaft, a lower anchor plate, a tensioning shaft, a tensioning screw and fiber cloth. The upper anchor plate and the lower anchor plate are connected to the fixing shaft, the fixing shaft and the tensioning shaft are inserted into a notch of the steel frame, and the tensioning screw is connected with the tensioning shaft and the steel frame. During reinforcement, one end of the fiber cloth is fixed to the lower portion of the fixing shaft through the lower anchor plate, then the fiber cloth is wound around the tensioning shaft and the fixing shaft to the required layer number, and the other end of the fiber cloth is fixed to the upper portion of the fixing shaft through the upper anchor plate; after prestress is applied, surface treatment and gluing are conducted; and the reinforcing device is fixed to the surface of the steel structure through a magnetic fixator, redundant fiber cloth is cut off after the dipping glue is maintained, and the reinforcing device is taken down. Construction is easy and convenient, the reinforcing efficiency is high, punching and anchoring do not need to be conducted on the steel structure, and lossless reinforcing of the prestressed fiber cloth on the steel structure is achieved.

Description

Technical Field

[0001] The present invention relates to the field of engineering structure reinforcement, in particular to a prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structures, and also to a prestressed fiber cloth non-destructive reinforcement method for local reinforcement of steel structures. Background Art

[0002] Steel structures have been widely used in buildings and transportation infrastructure. Under long-term service loads, many steel structures face the threat of fatigue cracking, which greatly reduces the durability and service safety of steel structures. Therefore, it is necessary to carry out fatigue resistance reinforcement in key areas of steel structures and improve the fatigue performance of local details of steel structures. Compared with traditional reinforcement materials such as concrete and steel, fiber cloth (such as carbon fiber cloth, basalt fiber cloth, etc.) has the advantages of light weight, high strength and good corrosion resistance. However, when fiber cloth is used for structural reinforcement, its high strength characteristics cannot be brought into play, resulting in the reinforcement effect in the normal use stage and a great waste of material strength. Compared with non-prestressed reinforcement, prestressed reinforcement can not only greatly improve the strength utilization rate of reinforcement materials, but also significantly improve the reinforcement effect in the normal use stage and limit state. In particular, when prestressed fiber cloth is used for fatigue resistance reinforcement of steel structures, the fatigue resistance of areas with insufficient fatigue performance can be significantly improved. Even for cracked areas, the propagation rate of fatigue cracks in steel structures can be effectively reduced, and even the effect of completely stopping cracks can be achieved.

[0003] Then, when the existing prestressed fiber cloth or fiberboard reinforcement method is used for reinforcement, holes are usually drilled on the surface of the structure due to the need to fix anchors and tension prestress. However, drilling will damage the cross section of the steel structure. What is more serious is that the edge of the hole is a stress concentration area, which may cause new fatigue cracks in the drilling area. On the other hand, since a single layer of fiber cloth is very thin, multiple layers of fiber cloth are usually required to reinforce the steel structure. However, the winding method of the existing anchoring device is complicated, resulting in low construction efficiency and inconvenience for engineering application. Therefore, in the face of local reinforcement needs caused by fatigue damage of steel structures, how to perform non-destructive reinforcement with prestressed fiber cloth is an important technical problem that needs to be solved urgently. Summary of the invention

[0004] Purpose of the invention: In view of the shortcomings of the prior art, the present invention proposes a device and method for non-destructive reinforcement of prestressed fiber cloth for local reinforcement of steel structure. By tensioning multiple layers of prestressed fiber cloth at the same time and without the need to drill holes and anchor the steel structure, non-destructive reinforcement of the steel structure by prestressed fiber cloth is conveniently and efficiently achieved.

[0005] Technical solution: The present invention provides a non-destructive reinforcement device for prestressed fiber cloth for local reinforcement of steel structure, comprising a steel frame, an upper anchor plate, a fixed shaft, a lower anchor plate, a tensioning shaft, a tensioning screw and a fiber cloth;

[0006] The steel frame is provided with a first notch, a second notch, and a waist-shaped hole; the two ends of the fixed shaft are inserted into the first notch, and the two ends of the tensioning shaft are inserted into the second notch; a through slit is provided on the side of the fixed shaft;

[0007] The upper anchor plate is located above the fixed axis in the steel frame; the lower anchor plate is located below the fixed axis in the steel frame; and the tensioning screw rod is connected with the tensioning axis after passing through the waist-shaped hole on the steel frame.

[0008] The fixed shaft is provided with an extended end, a threaded through hole and a through slot; the extended end is inserted into the notch of the steel frame so that the fixed shaft is connected to the steel frame.

[0009] The tensioning shaft is provided with an elongated end and a circular shaft; a rectangular block is connected between the elongated end and the circular shaft.

[0010] A circular through hole for passing the tensioning screw rod is arranged on the tensioning shaft.

[0011] The lower anchor plate is provided with a countersunk hole, and the lower anchor plate is connected to the fixed shaft through the countersunk hole. The function of the countersunk hole is to hide the nut of the installed bolt and reduce the installation error.

[0012] A circular through hole is provided on the upper anchor plate, and the upper anchor plate is connected with the fixed shaft through the circular through hole.

[0013] The through seam on the fixed shaft is a rectangular through seam.

[0014] The utility model also comprises a magnetic fixer, the lower surface of which is flush with the lower surface of the steel frame.

[0015] The present invention provides a method for local reinforcement of steel structure, which is implemented by using a prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure. The reinforcement method includes the following steps:

[0016] Step (1), installing a magnetic fixture on the steel frame, and aligning the lower surface of the magnetic fixture with the lower surface of the steel frame;

[0017] Step (2), placing one end of the fiber cloth at the starting point of the lower anchor plate, rotating the lower anchor plate so that one end of the fiber cloth is wrapped around the lower anchor plate for multiple turns, and then fixing the lower anchor plate to the lower surface of the fixed shaft;

[0018] Step (3), winding the fiber cloth around the circular axis of the tensioning shaft and through the through-slit of the fixed shaft, and performing winding of one layer of the fiber cloth; repeating step (3) until the fiber cloth reaches the set number of winding layers; placing the other end of the fiber cloth on the lower surface of the upper anchor plate, rotating the upper anchor plate so that the other end of the fiber cloth is wound around the upper anchor plate for multiple turns, and then fixing the upper anchor plate on the upper surface of the fixed shaft;

[0019] Step (4), after the tensioning screw is passed through the circular through hole of the tensioning shaft and the waist-shaped hole of the steel frame, the tensioning screw and the tensioning shaft are connected and fixed to the steel frame; the fiber cloth is driven to slide downward by the self-weight of the upper anchor plate, the fixed shaft, the lower anchor plate, the tensioning shaft, and the tensioning screw, so that the lower surface of the steel frame and the outermost surface of the fiber cloth are in the same plane; the prestress is applied to the fiber cloth by synchronously rotating the nuts on the outer side of the steel frame with two torque wrenches;

[0020] Step (5), pre-treating the area to be reinforced, and applying the impregnating glue to the adhesive area of ​​the area to be reinforced;

[0021] Step (6), applying impregnating glue to the fiber cloth to which prestress has been applied on the lower side, and after the impregnated area of ​​the fiber cloth overlaps with the glue-coated area of ​​the area to be reinforced, adsorbing the non-destructive reinforcement device to the surface of the area to be reinforced by a magnetic fixture;

[0022] Step (7), after the impregnated glue is cured to the required strength, use a wrench to simultaneously rotate the nuts on the outside of the steel frame to release the prestress, then cut off the excess fiber cloth, remove the non-destructive reinforcement device through the magnetic fixture, and complete the non-destructive reinforcement of the prestressed fiber cloth on the steel structure.

[0023] In step (5), the surface of the area to be reinforced is pre-treated by removing oil, rust and drying, and the impregnating glue is applied to the adhesive area of ​​the area to be reinforced.

[0024] Working principle: The steel frame of the present invention is provided with two notches and a waist-shaped hole. The two notches are used to connect the fixed shaft and the tensioning shaft, and the waist-shaped hole is used to allow the tensioning screw to pass through. The fixed shaft, the tensioning shaft and the tensioning screw move along the two notches and the waist-shaped hole to achieve the purpose of adjusting the position of the fiber cloth.

[0025] The upper anchor plate is provided with a circular through hole and a rounded corner; the lower anchor plate is provided with a countersunk hole and a rounded corner; the upper anchor plate and the lower anchor plate are fixed to the fixed shaft by bolts and hexagon socket bolts respectively. The tensioning shaft is inserted into the notch of the steel frame, and the tensioning screw passes through the waist-shaped hole on the steel frame and is connected to the tensioning shaft.

[0026] When the present invention is reinforced, the extended end of the fixed shaft extends into the corresponding notch of the steel frame, and the fixed shaft slides up and down in the notch but cannot slide forward and backward. The extended end of the tensioning shaft extends into the notch of the steel frame and can slide up and down and left and right; the tensioning screw passes through the waist-shaped hole on the steel frame and the circular through hole on the tensioning shaft in turn, and is connected by a nut; during the tensioning process of the fiber cloth, each layer of the fiber cloth realizes self-regulation of internal stress under the action of the tensioning force, so as to achieve the purpose of uniform stress of each layer of the fiber cloth.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] (1) The non-destructive reinforcement device of the present invention is adsorbed on the surface of the steel structure to be reinforced by a magnetic fixer. The entire reinforcement process does not require drilling holes on the steel structure, thereby achieving non-destructive reinforcement of the prestressed fiber cloth.

[0029] (2) After the reinforcement is completed, only the prestressed fiber cloth used for reinforcement is left, and the other parts of the reinforcement device can be removed and reused, saving the reinforcement cost.

[0030] (3) By reciprocatingly winding the fiber cloth between the fixed axis and the tensioning axis of the reinforcement device, it is convenient to carry out multi-layer prestressed fiber cloth reinforcement. At the same time, during the tensioning process, each layer of fiber cloth realizes "internal stress self-regulation" under the action of the tensioning force, so as to achieve the purpose of uniform stress in each layer of fiber cloth.

[0031] (4) Both ends of the fiber cloth are anchored by wrapping around the anchor plate and forming an extrusion force with the fixed shaft through bolts, thereby achieving convenient and efficient anchoring.

[0032] (5) The application of prestress is convenient, and the installation and removal of the reinforcement device on the steel structure are convenient, achieving high efficiency of reinforcement construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the structure of the U-rib of the orthotropic bridge deck reinforced by the present invention in the embodiment;

[0034] Figure 2 It is a schematic diagram of the overall structure of the non-destructive reinforcement device of the present invention;

[0035] Figure 3 It is a schematic diagram of the steel frame structure of the non-destructive reinforcement device of the present invention;

[0036] Figure 4 is a schematic diagram of the fixed axis structure of the non-destructive reinforcement device of the present invention;

[0037] Figure 5 It is a schematic diagram of the tensioning shaft structure of the non-destructive reinforcement device of the present invention;

[0038] Figure 6 It is a schematic diagram of the processing and forming structure of the steel frame, fixed axis and tension axis of the non-destructive reinforcement device of the present invention;

[0039] Figure 7 is a top view of the lower anchor plate of the non-destructive reinforcement device of the present invention;

[0040] Figure 8 is a bottom view of the lower anchor plate of the non-destructive reinforcement device of the present invention;

[0041] Fig. 9 Schematic diagram of the upper anchor plate of the non-destructive reinforcement device of the present invention;

[0042] Fig.10It is a schematic diagram of the assembly of the upper anchor plate, the fixed shaft and the lower anchor plate of the non-destructive reinforcement device of the present invention;

[0043] Fig.11 Schematic diagram of the fiber cloth winding path of the non-destructive reinforcement device of the present invention;

[0044] Fig.12 It is a schematic diagram of the magnetic fixer of the non-destructive reinforcement device of the present invention. DETAILED DESCRIPTION

[0045] like Figures 1 to 12 As shown, the prestressed fiber cloth non-destructive reinforcement device and reinforcement method for local reinforcement of steel structure of the present invention are used to reinforce the U-rib 9 weld joint of the orthotropic steel bridge deck to improve the fatigue resistance of this position.

[0046] In this embodiment, due to the long-term exposure to wind loads and temperature effects, local cracks appear at the position of the weld 10 of the U-rib 9 of the orthotropic steel bridge deck. The prestressed fiber cloth non-destructive reinforcement device of the present invention is used to locally reinforce it to reduce the width of the existing cracks, slow down the crack development rate, effectively improve its fatigue resistance, and extend its service life.

[0047] like Figure 2 As shown, the prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure of the present invention includes a steel frame 1, an upper anchor plate 2, a fixed shaft 3, a lower anchor plate 4, a tensioning shaft 5, a tensioning screw 6 and a fiber cloth 7.

[0048] like Figure 3 As shown, the steel frame 1 is provided with a first slot 1-1, a second slot 1-2, and two waist-shaped holes 1-3, the two ends of the fixed shaft 3 are inserted into the first slot 1-1, and the two ends of the tensioning shaft 5 are inserted into the second slot 1-2. The tensioning screw 6 passes through the waist-shaped holes 1-3.

[0049] like Figure 4 As shown, the fixed shaft 3 is provided with an extended end 3-1, a threaded through hole 3-2 and a through slit 3-3. The fixed shaft 3 is connected by being inserted into the first notch 1-1 of the steel frame 1 through the extended ends 3-1 at both ends. The width of the first notch 1-1 is the same as the width of the extended end 3-1, and the height of the first notch 1-1 is higher than the height of the extended end 3-1, so that the fixed shaft 3 can slide up and down along the notch 1-1. The edge of the through slit 3-3 is processed with a rounded corner 3-4. In this embodiment, the through slit 3-3 is a rectangular through slit.

[0050] like Figure 5As shown, the tensioning shaft 5 is provided with an elongated end 5-1 and a round shaft 5-4, and a rectangular block 5-2 is connected between the elongated end 5-1 and the round shaft 5-4. The tensioning shaft 5 is connected by inserting the elongated ends 5-1 at both ends into the second notch 1-2 of the steel frame 1, and the height of the second notch 1-2 is higher than the height of the elongated end 5-1 to meet the requirement of the tensioning shaft 5 sliding up and down along the second notch 1-2. The width of the second notch 1-2 is greater than the width of the elongated end 5-1, so as to facilitate the left and right sliding of the tensioning shaft 5 when prestress is applied. A circular through hole 5-3 is opened on the side of the tensioning shaft 5.

[0051] When the steel frame 1 is manufactured, the two ends of the fixed shaft 3 are inserted into the first notch 1-1, and the tensioning shaft 5 is inserted into the second notch 1-2 of the steel frame 1. Figure 6 shown.

[0052] like Figures 7 to 10 As shown, a countersunk hole 4-1 is formed on the surface of the lower anchor plate 4, and a rounded corner 4-2 is processed on the side of the lower anchor plate 4. After one end of the fiber cloth 7 is wrapped around the lower anchor plate 4, the upper surface 4-3 of the lower anchor plate 4 is brought into contact with the lower surface 3-6 of the fixed shaft 3, and then the fiber cloth 7 is fixed by a hexagon socket bolt, so that the end of the fiber cloth 7 is clamped between the lower anchor plate 4 and the fixed shaft 3 to achieve anchoring of the end of the fiber cloth 7, and the nut of the hexagon socket bolt is hidden in the countersunk hole 4-1.

[0053] The upper anchor plate 2 is provided with a circular through hole 2-1 and a rounded corner 2-2. After the other end of the fiber cloth 7 is wrapped around the upper anchor plate 2, the lower surface 2-4 of the upper anchor plate 2 is brought into contact with the upper surface 3-5 of the fixed shaft 3 and fixed by bolts, thereby clamping the other end of the fiber cloth 7 between the upper anchor plate 2 and the fixed shaft 3 to achieve the anchoring of the other end of the fiber cloth 7.

[0054] like Fig.10 As shown, the width of the upper anchor plate 2 and the lower anchor plate 4 is equal to the width of the fixed shaft 3. The best way is that the widths of the three are equal. The length of the upper anchor plate 2 and the lower anchor plate 4 is equal to the length of the fixed shaft 3 excluding the length of the extension end 3-1, so as to ensure that the upper anchor plate 2 and the lower anchor plate 4 are installed in the steel frame 1.

[0055] like Fig.11As shown, when winding the anchoring fiber cloth 7, one end of the fiber cloth 7 is placed at the starting position, and the lower anchor plate 4 is rotated 720° clockwise according to the "a" path, so that one end of the fiber cloth 7 is wound around the lower anchor plate 4 for 2 turns, and the lower anchor plate 4 is fixed to the lower surface 3-6 of the fixed shaft 3; then the fiber cloth 7 is wound between the fixed shaft 3 and the tensioning shaft 5 to the required number of layers according to the "b" and "c" paths; thereafter, the other end of the fiber cloth 7 is placed on the lower surface 2-4 of the upper anchor plate 2 according to the "d" path, and the upper anchor plate 2 is rotated 720° counterclockwise according to the "e" path, so that the other end of the fiber cloth 7 is wound around the upper anchor plate 2 for 2 turns, and the upper anchor plate 2 is fixed to the upper surface 3-5 of the fixed shaft 3 with bolts, thus completing the winding and anchoring of the fiber cloth 7.

[0056] like Figure 2 As shown, after the fiber cloth 7 is wound and anchored, two torque wrenches are used to simultaneously rotate the two nuts on the outside of the steel frame 1. The torque value of the torque wrench is observed while rotating the nuts. When the designed torque value is reached, the torque wrench is stopped from being rotated, i.e., the tension is extended to the desired prestress level.

[0057] like Figure 1 and Fig.12 As shown, in order to achieve lossless reinforcement, the present embodiment fixes the reinforcement device to the U-rib 9 of the steel bridge deck to be reinforced by means of a magnetic fixture 8. The magnetic fixture 8 is provided with a knob 8-1 and "ON" and "OFF" indication marks. The magnetic fixture 8 is connected to the short side of the steel frame 1 by welding or gluing. When connected, the lower surface 1-5 of the steel frame 1 is flush with the lower surface 8-2 of the magnetic fixture 8. The magnetic switch of the magnetic fixture 8 is controlled by turning the knob 8-1.

[0058] The method for locally reinforcing a steel structure using a prestressed fiber cloth non-destructive reinforcement device of the present invention comprises the following steps:

[0059] (1) The magnetic fixture 8 is installed on the steel frame 1 by welding or gluing, and the lower surface 8-2 of the magnetic fixture 8 is flush with the lower surface 1-5 of the steel frame 1 during installation;

[0060] (2) Place one end of the fiber cloth 7 on the Fig.11 At the starting position of the lower anchor plate 4 shown, the lower anchor plate 4 is rotated 720° clockwise along the path "a", so that one end of the fiber cloth 7 is wrapped around the lower anchor plate 4 for 2 turns, and then the lower anchor plate 4 is fixed to the lower surface 3-6 of the fixed shaft 3 by the hexagon socket bolt, and the hexagon socket bolt is hidden in the countersunk hole 4-1 of the lower anchor plate 4;

[0061] (3) The fiber cloth 7 is wound around the circular axis 5-4 of the tensioning shaft 5 and the rectangular through-slit 3-3 of the fixed shaft 3 in accordance with the paths "b" and "c", and is wound between the fixed shaft 3 and the tensioning shaft 5 to the required number of layers. Then, the other end of the fiber cloth 7 is placed on the lower surface 2-4 of the upper anchor plate 2 in accordance with the path "d", and the upper anchor plate 2 is rotated 720° counterclockwise in accordance with the path "e", so that the other end of the fiber cloth 7 is wound around the upper anchor plate 2 for 2 turns, and the upper anchor plate 2 is fixed to the upper surface 3-5 of the fixed shaft 3 with bolts, thereby completing the winding and anchoring of the fiber cloth 7;

[0062] (4) Pass two tensioning screws 6 through the circular through hole 5-3 of the tensioning shaft 5 and the waist-shaped hole 1-3 of the steel frame 1 in sequence, and connect the tensioning screws 6, the tensioning shaft 5 and the steel frame 1 through nuts. Then place the reinforcement device on a plane, and drive the fiber cloth 7 to slide slightly downward through the self-weight of the upper anchor plate 2, the fixed shaft 3, the lower anchor plate 4, the tensioning shaft 5 and the tensioning screws 6, so that the lower surface 1-5 of the steel frame 1 and the outermost surface of the fiber cloth 7 are in the same plane; use two torque wrenches to synchronously rotate the two nuts on the outer side of the steel frame 1 to apply prestress to the fiber cloth 7;

[0063] (5) The U-rib 9 to be reinforced is pre-treated by removing oil stains, rust, grinding, and drying, and the impregnating glue is applied to the U-rib 9 to be glued;

[0064] (6) Apply impregnation glue to the fiber cloth 7 with prestress applied on the lower side, move the reinforcement device to the surface of the U rib 9, and after the impregnation area of ​​the fiber cloth 7 coincides with the glue-coated area on the surface of the U rib 9, rotate the knob 8-1 of the magnetic table base 8 to "ON" to adsorb the reinforcement device to the surface of the U rib 9;

[0065] (7) After the impregnation glue is cured to the required strength, use a wrench to simultaneously rotate the two nuts on the outside of the steel frame 1 to release the prestress, then cut off the excess fiber cloth 7, rotate the knob 8-1 of the magnetic fixer 8 to "OFF" to remove the reinforcement device, and complete the non-destructive reinforcement of the prestressed fiber cloth of the U rib 9.

Claims

1. A non-destructive reinforcement device for prestressed fiber cloth for local reinforcement of steel structure, characterized by: It comprises a steel frame (1), an upper anchor plate (2), a fixed shaft (3), a lower anchor plate (4), a tensioning shaft (5), a tensioning screw rod (6) and a fiber cloth (7); The steel frame (1) is provided with a first notch (1-1), a second notch (1-2), and a waist-shaped hole (1-3); the two ends of the fixed shaft (3) are inserted into the first notch (1-1), and the two ends of the tensioning shaft (5) are inserted into the second notch (1-2); the side surface of the fixed shaft (3) is provided with a through slit (3-3); The upper anchor plate (2) is located above the fixed shaft (3) in the steel frame (1); the lower anchor plate (4) is located below the fixed shaft (3) in the steel frame (1); and the tensioning screw rod (6) is connected to the tensioning shaft (5) after passing through the waist-shaped hole (1-3) on the steel frame (1).

2. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1 is characterized in that: The fixed shaft (3) is provided with an extended end (3-1), a threaded through hole (3-2) and a through slit (3-3); the extended end (3-1) is inserted into a notch (1-1) of the steel frame (1).

3. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1 is characterized in that: The tensioning shaft (5) is provided with an elongated end (5-1) and a circular shaft (5-4); a rectangular block (5-2) is connected between the elongated end (5-1) and the circular shaft (5-4).

4. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1, characterized in that: The tensioning shaft (5) is provided with a circular through hole (5-3) through which the tensioning screw rod (6) passes.

5. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1, characterized in that: The lower anchor plate (4) is provided with a countersunk hole (4-1), and the lower anchor plate (4) is connected to the fixed shaft (3) via the countersunk hole (4-1).

6. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1, characterized in that: A circular through hole (2-1) is provided on the upper anchor plate (2), and the upper anchor plate (2) is connected to the fixed shaft (3) via the circular through hole (2-1).

7. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1, characterized in that: The through slit (3-3) on the fixed shaft (3) is a rectangular through slit.

8. The prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1, characterized in that: It also includes a magnetic fixer (8), the lower surface of which is flush with the lower surface of the steel frame (1).

9. A method for local reinforcement of a steel structure, characterized in that: The reinforcement method is implemented by using the prestressed fiber cloth non-destructive reinforcement device for local reinforcement of steel structure according to claim 1, and the reinforcement method comprises the following steps: Step (1), installing a magnetic fixture (8) on the steel frame (1), and aligning the lower surface (8-2) of the magnetic fixture (8) with the lower surface (1-5) of the steel frame (1); Step (2), placing one end of the fiber cloth (7) at the starting point of the lower anchor plate (4), rotating the lower anchor plate until one end of the fiber cloth (7) is wrapped around the lower anchor plate (4) for multiple turns, and then fixing the lower anchor plate (4) to the lower surface (3-6) of the fixed shaft (3); Step (3), winding the fiber cloth (7) around the circular axis (5-4) of the tensioning axis (5) and through the through slit (3-3) of the fixed axis (3), and performing winding of one layer of the fiber cloth; repeating step (3) until the fiber cloth (7) reaches a set number of winding layers; placing the other end of the fiber cloth (7) on the lower surface (2-4) of the upper anchor plate (2), rotating the upper anchor plate (2) until the other end of the fiber cloth (7) is wound around the upper anchor plate (2) for multiple turns, and then fixing the upper anchor plate (2) on the upper surface (3-5) of the fixed axis (3); Step (4), after the tensioning screw (6) passes through the circular through hole (5-3) of the tensioning shaft (5) and the waist-shaped hole (1-3) of the steel frame (1), the tensioning screw (6) and the tensioning shaft (5) are connected and fixed to the steel frame (1); the fiber cloth (7) is driven to slide downward by the self-weight of the upper anchor plate (2), the fixed shaft (3), the lower anchor plate (4), the tensioning shaft (5) and the tensioning screw (6), so that the lower surface (1-5) of the steel frame (1) and the outermost surface of the fiber cloth (7) are in the same plane; the prestress is applied to the fiber cloth (7) by synchronously rotating the nuts on the outside of the steel frame (1) with two torque wrenches; Step (5), pre-treating the area to be reinforced, and applying the impregnating glue to the adhesive area of ​​the area to be reinforced; Step (6), applying impregnating glue to the fiber cloth (7) to which prestress has been applied on the lower side, and after the impregnated area of ​​the fiber cloth (7) overlaps with the glue-coated area of ​​the area to be reinforced, adsorbing the non-destructive reinforcement device to the surface of the area to be reinforced by a magnetic fixture (8); Step (7), after the impregnated glue is cured to the required strength, use a wrench to simultaneously rotate the nuts on the outside of the steel frame (1) to release the prestress, then cut off the excess fiber cloth (7), remove the non-destructive reinforcement device through the magnetic fixture (8), and complete the non-destructive reinforcement of the prestressed fiber cloth on the steel structure.

10. The method for local reinforcement of a steel structure according to claim 9, characterized in that: In step (5), the surface of the area to be reinforced is pre-treated by removing oil, rust and drying, and the impregnating glue is applied to the adhesive area of ​​the area to be reinforced.

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