Method for reinforcing distorted I-shaped steel beam

Abstract

The invention discloses a method for reinforcing a distorted I-shaped steel beam, which only needs to arrange a first section increasing structure and a second section increasing reinforcing structure on a deformed section and a non-deformed section of the distorted I-shaped steel beam to locally reinforce the distorted I-shaped steel beam, and does not need to reinforce the whole beam and support the whole beam, so that a building can operate as usual. The first section increasing reinforcing structure and the second section increasing reinforcing structure are both located below the upper flange, reinforcing operation is carried out at the beam bottom, the maintenance structure does not need to be detached and replaced, meanwhile, stress redistribution is achieved through combination of the first stiffening plate and the second stiffening plate, and the torsional bearing capacity and out-of-plane stability of the distorted I-shaped steel beam are improved through the lateral tie bars; the technical problems that in the prior art, in-situ hot working correction is difficult to implement and low in effect, a maintenance structure needs to be dismantled in replacement work, a building needs to be stopped in the construction period, supporting scheme demonstration is conducted on local dismantling of the building, the association surface is large, construction is difficult, and a traditional section enlarging method needs full-beam-span reinforcement and is high in cost are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of deformed steel beam reinforcement, and in particular to a method for reinforcing a twisted and deformed I-shaped steel beam. Background Art

[0002] Portal frame structures are a common form of steel structure. Due to their rational load-bearing characteristics, convenient construction, and cost-effectiveness, they are widely used in various industrial and civil buildings, including single-story factories, industrial warehouses and logistics centers, exhibition halls, auto dealerships, farmers' markets, shopping malls, supermarkets, stadiums, auditoriums, station waiting rooms, and farms. Existing portal frame structures may experience defects such as excessive deformation, localized buckling, and fatigue damage in steel components over the long term due to factors such as impact from equipment and construction quality.

[0003] I-beams are a common type of steel beam used in portal frames. For warped and deformed I-beams, the standard stipulates that "hot working methods may be used for correction. When correction is difficult, replacement or reinforcement should be performed." However, for severely warped and deformed steel members, in-situ hot working correction is difficult or ineffective. Replacement requires the removal of associated supporting structures (such as roof panels, purlins, and bracing). This also requires the decommissioning of existing buildings during construction, and requires the verification of a comprehensive support plan for partial demolition. This involves a large area, making construction difficult and challenging. Traditional methods of increasing cross-sections require full-span reinforcement, which is costly. Summary of the Invention

[0004] In response to the above shortcomings, the present invention provides a method for reinforcing a twisted and deformed I-beam, thereby overcoming the technical problems existing in the prior art and completing the reinforcement and maintenance of the twisted and deformed I-beam without dismantling it. The specific technical solution is as follows: A method for reinforcing a twisted and deformed I-beam, comprising the following steps: S1: Conduct on-site measurement of the twisted and deformed I-beam to obtain the actual twist length of the actual twisted area of ​​the twisted and deformed I-beam and the actual twist position of the actual twisted area of ​​the twisted and deformed I-beam in the entire beam; S2: establishing finite element mechanical models for the twisted and deformed I-beam and the standard component corresponding to the twisted and deformed I-beam, respectively, and applying identical loads to the two finite element mechanical models to generate a stress nephogram and a standard stress nephogram of the twisted and deformed I-beam; S3: Based on the stress nephogram, the standard stress nephogram, the actual twist length, and the actual twist position of the twisted and deformed I-beam, dividing the twisted and deformed I-beam into a deformed section and a first undeformed section, wherein the point where the stress on the deformed section is the maximum deformation point, and the first undeformed sections are located at both ends of the deformed section; S4: dividing a second undeformed segment at an end of each first undeformed segment away from the deformed segment, and unifying the first undeformed segment and the second undeformed segment into an undeformed segment; S5: first stiffening plates are provided at the maximum deformation point, at both ends of the deformation section, and on both sides of the web of the undeformed section away from one end of the deformation section; S6: providing a first cross-section enlarging reinforcement structure on the deformed section, and providing a second cross-section enlarging reinforcement structure on the undeformed section; S7: A lateral tie rod is installed on one of the first stiffening plates arranged at the maximum deformation position, and the other end of the lateral tie rod is connected to the steel beam adjacent to the twisted and deformed I-beam, thereby completing the reinforcement of the twisted and deformed I-beam.

[0005] Preferably, the first cross-section enlarged reinforcement structure includes a first newly added upper wing plate, a first newly added lower wing plate, a first newly added vertical web plate, a newly added inclined web plate and a lower flange connecting plate; The first newly added upper wing plate is welded to the bottom surface of the upper flange of the steel beam of the deformation section and is distributed on both sides of the web of the steel beam of the deformation section. The first newly added lower wing plate is arranged below the lower flange of the steel beam of the deformation section, one end of which is welded to one end of the lower flange of the steel beam of the deformation section, and the other end is connected to the other end of the lower flange of the steel beam of the deformation section through the lower flange connecting plate. The width of the first newly added lower wing plate is greater than the width of the lower flange of the steel beam of the deformation section. The first newly added upper wing plate is parallel to the first newly added lower wing plate. The top end of the first newly added vertical web is welded to the first newly added upper wing plate, and the other end is welded to the first newly added lower wing plate. The top end of the newly added inclined web is welded to the first newly added upper wing plate, and the other end is welded to the first newly added lower wing plate and connected to the lower flange of the steel beam of the deformation section.

[0006] Preferably, when the width of the first newly added lower wing panel is greater than or equal to 350 mm, the number of the lower flange connecting plates is at least two, and the distance between the first newly added lower wing panel and the lower flange of the steel beam of the deformation section and at least two of the lower flange connecting plates is not greater than 200 mm.

[0007] Preferably, the second cross-section enlarged reinforcement structure includes a second newly added upper wing plate, a second newly added lower wing plate and a second newly added vertical web plate; The second newly added upper wing plate is welded to the bottom surface of the upper flange of the steel beam of the undeformed section and is distributed on both sides of the web of the steel beam of the undeformed section. The second newly added lower wing plate is welded to the bottom surface of the lower flange of the steel beam of the undeformed section. The second newly added vertical web is arranged on both sides of the web of the steel beam of the undeformed section, the top end of which is welded to the second newly added upper wing plate, and the bottom end is welded to the lower flange of the steel beam of the undeformed section. The second newly added upper wing plate is parallel to the second newly added lower wing plate.

[0008] Preferably, the thickness of the upper flange and the lower flange of the twisted and deformed I-beam is defined as H1, and the thickness of the first newly added upper wing plate, the first newly added lower wing plate, the second newly added upper wing plate and the second newly added lower wing plate is h1, then H1 and h1 satisfy h1≤H1.

[0009] Preferably, the thickness of the web of the twisted and deformed I-beam is defined as H2, the thickness of the first newly added vertical web, the second newly added vertical web and the newly added inclined web is h2, then H2 and h2 satisfy h2≤H2.

[0010] Preferably, a plurality of second stiffening plates are arranged on both sides of the web of the deformed section and the undeformed section at a first distance interval. The first stiffening plate and the second stiffening plate located in the deformed section are tightly attached to the first newly added lower wing plate and the upper flange, web and lower flange of the deformed section steel beam, and pass through the first newly added vertical web or the newly added inclined web. The first stiffening plate and the second stiffening plate located in the undeformed section are tightly attached to the upper flange, web and lower flange of the undeformed section steel beam, and pass through the second newly added vertical web.

[0011] Preferably, the first distance is 500 mm.

[0012] Preferably, the lateral protrusion of the first stiffening plate is provided with a connecting block, the lateral tie rod is connected to the first stiffening plate via the connecting block, and the other end of the lateral tie rod is connected to the top end of the steel beam adjacent to the twisted and deformed I-beam.

[0013] Preferably, the length of the first undeformed segment is defined as D, and the length of the second undeformed segment is defined as d, and then D and d satisfy D / 3≤d≤D / 2.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for reinforcing a twisted and deformed I-beam, which comprises providing a box-type first-section enlarged reinforcement structure adapted to the twisted shape on the deformed section of the twisted and deformed I-beam, and providing a box-type second-section enlarged reinforcement structure on the undeformed section extending outward from the deformed section. Only the deformed section and the undeformed section need to be locally reinforced, without the need for full-span reinforcement or overall support. Physical reinforcement methods are used instead of thermal correction to complete the repair of the deformed beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly describes the drawings required for describing the embodiments. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0016] Figure 1 It is an elevation view of the twisted and deformed I-beam of the present invention.

[0017] Figure 2 It is a three-dimensional stereogram of the twisted and deformed I-beam in the present invention.

[0018] Figure 3 It is a cross-sectional view of the deformation section in the present invention.

[0019] Figure 4 It is a structural schematic diagram of the deformation section in the present invention.

[0020] Figure 5 It is a structural schematic diagram of the deformation section (including lateral tie rods) in the present invention.

[0021] Figure 6 It is a structural schematic diagram of the undeformed section in the present invention.

[0022] 10-twisted and deformed I-beam, 20-deformed section, 21-first newly added upper wing plate, 22-first newly added lower wing plate, 23-first newly added vertical web plate, 24-newly added inclined web plate, 25-lower flange connecting plate, 30-undeformed section, 31-second newly added upper wing plate, 32-second newly added lower wing plate, 33-second newly added vertical web plate, 40-first stiffening plate, 50-lateral tie rod, 60-second stiffening plate. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0025] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The terms "first," "second," and "third" are used solely for descriptive purposes and to distinguish technical features. They are not to be construed as indicating or implying relative importance, or as implicitly specifying the number or order of the technical features indicated.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Example like Figures 1 to 6 As shown, an embodiment of the present invention provides a method for reinforcing a twisted and deformed I-beam, the method comprising the following steps: Step S1: performing on-site measurement on the twisted and deformed I-beam 10 to obtain the actual twist length of the actual twisted region of the twisted and deformed I-beam and the actual twist position of the actual twisted region of the twisted and deformed I-beam in the entire beam.

[0028] Step S2: establishing finite element mechanical models for the twisted and deformed I-beam 10 and the standard parts corresponding to the twisted and deformed I-beam respectively, and applying exactly the same load in the two finite element mechanical models to generate a stress nephogram of the twisted and deformed I-beam and a standard stress nephogram.

[0029] Step S3: Based on the stress cloud map, standard stress cloud map, actual twisting length and actual twisting position of the twisted and deformed I-beam, a deformation section 20 and a first undeformed section are divided on the twisted and deformed I-beam. The point with the maximum stress on the deformation section is the maximum deformation point, and the first undeformed section is located at both ends of the deformation section.

[0030] Among them, the deformation section 20 is divided by using the stress cloud map of the twisted and deformed I-beam, the actual twisting length and the actual twisting position. Based on the divided deformation section 20, the stress cloud map of the twisted and deformed I-beam and the standard stress cloud map, it can be known that the actual stress change range extends a distance beyond the deformation section 20 to the actual undeformed area of ​​the twisted and deformed I-beam, and the area at both ends of the deformation section 20 where the stress changes but is actually not deformed is divided into a first undeformed section.

[0031] Step S4: dividing a second undeformed segment at one end of each first undeformed segment away from the deformed segment, and unifying the first undeformed segment and the second undeformed segment into an undeformed segment 30 .

[0032] Specifically, the length of the first undeformed segment is defined as D, and the length of the second undeformed segment is defined as d, and then D and d satisfy D / 3≤d≤D / 2.

[0033] Step S5: first stiffening plates 40 are provided at the maximum deformation point, at both ends of the deformation section 20 , and on both sides of the web of the undeformed section 30 away from one end of the deformation section 20 .

[0034] Preferably, a plurality of second stiffening plates 60 are arranged on both sides of the web of the deformed section 20 and the undeformed section 30 at a first distance interval. The first stiffening plate 40 and the second stiffening plate 60 located in the deformed section 20 are tightly attached to the first newly added lower wing plate 22 and the upper flange, web and lower flange of the steel beam of the deformed section 20, and pass through the first newly added vertical web 23 or the newly added inclined web 24. The first stiffening plate 40 and the second stiffening plate 60 located in the undeformed section 30 are tightly attached to the upper flange, web and lower flange of the steel beam of the undeformed section 30, and pass through the second newly added vertical web 33.

[0035] In this embodiment, the first distance is 500 mm. If the first stiffening plate 40 and the second stiffening plate 60 should be provided at the same time at a certain position, the first stiffening plate 40 is retained.

[0036] Step S6: providing a first cross-section enlarging reinforcement structure on the deformed section 20 , and providing a second cross-section enlarging reinforcement structure on the undeformed section 30 .

[0037] Preferably, the first cross-section enlarged reinforcement structure includes a first newly added upper wing plate 21, a first newly added lower wing plate 22, a first newly added vertical web 23, a newly added inclined web 24 and a lower flange connecting plate 25, the first newly added upper wing plate 21 is welded below the upper flange of the steel beam of the deformation section 20, and is distributed on both sides of the steel beam web of the deformation section 20, the first newly added lower wing plate 22 is arranged below the lower flange of the steel beam of the deformation section 20, one end of which is welded to one end of the lower flange of the steel beam of the deformation section 20, and the other end is connected to the other end of the lower flange of the steel beam of the deformation section 20 through the lower flange connecting plate 25, the width of the first newly added lower wing plate 22 is greater than the width of the lower flange of the steel beam of the deformation section 20, the first newly added upper wing plate 21 is parallel to the first newly added lower wing plate 22, the top of the first newly added vertical web 23 is welded to the first newly added upper wing plate 21, and the other end is welded to the The first newly added lower wing panel 22 is welded, the top end of the newly added inclined web 24 is welded to the first newly added upper wing panel 21, and the other end is welded to the first newly added lower wing panel 22, and is connected to the lower flange of the steel beam of the deformed section 20. The second cross-section enlarged reinforcement structure includes a second newly added upper wing panel 31, a second newly added lower wing panel 32 and a second newly added vertical web panel 33. The second newly added upper wing panel 31 is welded below the upper flange of the steel beam of the undeformed section 30 and is distributed on both sides of the steel beam web of the undeformed section 30. The second newly added lower wing panel 32 is welded below the lower flange of the steel beam of the undeformed section 30. The second newly added vertical web panel 33 is arranged on both sides of the steel beam web of the undeformed section 30, and its top end is welded to the second newly added upper wing panel 31 and the bottom end is welded to the lower flange of the steel beam of the undeformed section 30. The second newly added upper wing panel 31 is parallel to the second newly added lower wing panel 32.

[0038] It is worth mentioning that, since in the deformation section 20, the first stiffening plate 40 and the second stiffening plate 60 are both closely attached to the first newly added lower wing plate 22 and the upper flange, lower flange and web of the steel beam of the deformation section 20, during the specific reinforcement construction process, the first newly added lower wing plate 22 should be welded below the lower flange of the steel beam of the deformation section 20, and at the same time, the lower flange connecting plate 25 should be welded between the first newly added lower wing plate 22 and the lower flange of the steel beam of the deformation section 20, and the lower flange connecting plate 25 and the lower flange of the steel beam of the deformation section 20 are welded by slot welding. Next, the first stiffening plate 40 and the second stiffening plate 60 are welded to the top surface of the first newly added lower wing plate 22 and the lower part of the upper flange, the upper part of the lower flange and the web of the deformed section 20 steel beam. Finally, the first newly added upper wing plate 21, the first newly added vertical web plate 23 and the newly added inclined web plate 24 are welded. Specifically, in the span direction of the twisted and deformed I-beam, both ends of the first newly added upper wing plate 21, the first newly added vertical web plate 23 and the newly added inclined web plate 24 are welded to the stiffening plate (the first stiffening plate or the second stiffening plate). , determined by whether the two ends are specifically the first stiffening plates or the second stiffening plates), the first newly added vertical web 23 is arranged on the concave side of the web of the steel beam of the deformed section 20, the newly added inclined web 24 is arranged on the convex side of the web of the steel beam of the deformed section 20, and the first newly added lower wing plate 22 is welded to the lower flange of the steel beam of the deformed section 20 on the concave side of the web of the steel beam of the deformed section 20; because in the undeformed section 30, the first stiffening plate 40 and the second stiffening plate 60 are both tightly attached to the upper flange, web and lower flange of the steel beam of the undeformed section 30 Therefore, during the specific reinforcement construction process, the first stiffening plate 40 and the second stiffening plate 60 should first be welded to the bottom of the upper flange, the top of the lower flange and the web of the undeformed section 30 steel beam, and finally the second newly added upper wing plate 31 and the second newly added vertical web 33 should be welded. Specifically, in the span direction of the twisted and deformed I-beam, both ends of the second newly added upper wing plate 31 and the second newly added vertical web 33 are welded to the stiffening plate (the first stiffening plate or the second stiffening plate, determined by whether the two ends are the first stiffening plate or the second stiffening plate).

[0039] Preferably, the thickness of the upper flange and the lower flange of the twisted and deformed I-beam 10 is defined as H1, the thickness of the first newly added upper wing plate 21, the first newly added lower wing plate 22, the second newly added upper wing plate 31 and the second newly added lower wing plate 32 is h1, then the H1 and the h1 satisfy h1≤H1, the thickness of the web of the twisted and deformed I-beam 10 is defined as H2, the thickness of the first newly added vertical web plate 23, the second newly added vertical web plate 33 and the newly added inclined web plate 24 is h2, then the H2 and the h2 satisfy h2≤H2, and the box-type is formed by arranging the first newly added upper wing plate 21, the first newly added lower wing plate 22, the first newly added vertical web plate 23, the newly added inclined web plate 24 and the lower flange connecting plate 25 The first cross-section enlarged reinforcement structure improves the bearing capacity and stiffness of the deformed section 20. A box-type second cross-section enlarged reinforcement structure is formed by arranging a second newly added upper wing plate 31, a second newly added lower wing plate 32 and a second newly added vertical web 33. The second cross-section enlarged reinforcement structure is arranged on the first undeformed section and the second undeformed section. Combined with the arrangement of the first stiffening plate 40 and the second stiffening plate 60, the stress redistribution effect is achieved on the premise of improving the bearing capacity and stiffness of the non-deformed section 20, ensuring a smooth transition in stiffness between the reinforced section (the deformed section and the non-deformed section are collectively referred to as the reinforced section) and the unreinforced section (the portion of the entire beam excluding the reinforced section) of the reinforced twisted and deformed I-beam, thereby avoiding sudden stress changes.

[0040] Preferably, when the width of the first newly added lower wing panel 22 is greater than or equal to 350 mm, the number of the lower flange connecting plates 25 is at least two, and the distance between the welding point between the first newly added lower wing panel 22 and the lower flange of the steel beam of the deformation section 20 and at least two of the lower flange connecting plates 25 is not greater than 200 mm.

[0041] In some preferred embodiments, by setting the number of the lower flange connecting plates 25 to at least two, and ensuring that the distance between the first newly added lower wing plate 22 and the lower flange of the steel beam of the deformation section 20 and at least two of the lower flange connecting plates 25 is not greater than 200 mm, that is, the distance between the first newly added lower wing plate 22 and the lower flange of the steel beam of the deformation section 20 and the adjacent lower flange connecting plates 25 is not greater than 200 mm, and the distance between two adjacent lower flange connecting plates 25 is also not greater than 200 mm, so as to improve the welding stability of the first newly added lower wing plate 22 and the lower flange of the steel beam of the deformation section 20, and at the same time, reduce the stress on a single weld.

[0042] Step S7: A lateral tie rod 50 is installed on one of the first stiffening plates 40 located at the maximum deformation position, and the other end of the lateral tie rod 50 is connected to the adjacent steel beam of the twisted and deformed I-beam 10 to complete the reinforcement of the twisted and deformed I-beam.

[0043] Preferably, the lateral protrusion of the first stiffening plate 40 is provided with a connecting block, and the lateral tie rod 50 is connected to the first stiffening plate 40 through the connecting block, and the other end of the lateral tie rod 50 is connected to the top end of the steel beam adjacent to the twisted and deformed I-beam 10.

[0044] In some preferred embodiments, the lateral tie rod 50 is connected to the first stiffening plate 40 located on the concave side of the web of the steel beam of the deformation section 20. By arranging the proximal end of the lateral tie rod 50 to be connected to the bottom end of the first stiffening plate 40 and the distal end to be connected to the top end of the adjacent steel beam, the lateral support of the twisted and deformed I-beam is increased, and the torsional bearing capacity and out-of-plane stability of the twisted and deformed I-beam are improved.

[0045] In summary, the present invention provides a method for reinforcing a twisted and deformed I-beam, which provides a box-type first-section enlarged reinforcement structure that adapts to the twisted shape on the deformed section of the twisted and deformed I-beam, and provides a box-type second-section enlarged reinforcement structure on the undeformed section extending outward from the deformed section. Only the deformed section and the undeformed section need to be locally reinforced, without the need for full-span reinforcement or overall support. Physical reinforcement methods are used instead of thermal correction to complete the repair of the deformed beam.

[0046] The foregoing descriptions of specific exemplary embodiments of the present invention are for the purpose of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although an embodiment of the present invention has been shown and described, this specific embodiment is only an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described can be combined in an appropriate manner in any one or more embodiments or examples. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can make modifications, substitutions, variations and various different selections and changes to the embodiments as needed without departing from the principles and purpose of the present invention after reading this specification, but they are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for reinforcing a twisted and deformed I-beam, characterized in that: The method comprises the following steps: S1: Conducting on-site measurement of the twisted and deformed I-beam (10) to obtain the actual twist length of the actual twisted region of the twisted and deformed I-beam and the actual twist position of the actual twisted region of the twisted and deformed I-beam in the entire beam; S2: establishing finite element mechanical models for the twisted and deformed I-beam (10) and the standard parts corresponding to the twisted and deformed I-beam, respectively, and applying identical loads in the two finite element mechanical models to generate a stress cloud diagram of the twisted and deformed I-beam and a standard stress cloud diagram; S3: Based on the stress cloud map of the twisted and deformed I-beam, the standard stress cloud map, the actual twist length and the actual twist position, a deformation section (20) and a first undeformed section are divided on the twisted and deformed I-beam, the point with the maximum stress on the deformation section is the maximum deformation point, and the first undeformed section is located at both ends of the deformation section; S4: dividing a second undeformed segment at one end of each first undeformed segment away from the deformed segment, and unifying the first undeformed segment and the second undeformed segment into an undeformed segment (30); S5: first stiffening plates (40) are provided at the maximum deformation point, at both ends of the deformation section (20), and on both sides of the web of the undeformed section (30) away from one end of the deformation section (20); S6: providing a first cross-section enlarging reinforcement structure on the deformed section (20), and providing a second cross-section enlarging reinforcement structure on the undeformed section (30); S7: A lateral tie rod (50) is installed on one of the first stiffening plates (40) located at the maximum deformation position, and the other end of the lateral tie rod (50) is connected to a steel beam adjacent to the twisted and deformed I-beam (10), thereby completing the reinforcement of the twisted and deformed I-beam.

2. The method for reinforcing a twisted and deformed I-beam according to claim 1, characterized in that: The first cross-section enlarged reinforcement structure comprises a first newly added upper wing plate (21), a first newly added lower wing plate (22), a first newly added vertical web plate (23), a newly added inclined web plate (24) and a lower flange connecting plate (25); The first newly added upper wing plate (21) is welded to the bottom surface of the upper flange of the steel beam of the deformation section (20) and is distributed on both sides of the web of the steel beam of the deformation section (20). The first newly added lower wing plate (22) is arranged below the lower flange of the steel beam of the deformation section (20), one end of which is welded to one end of the lower flange of the steel beam of the deformation section (20), and the other end is connected to the other end of the lower flange of the steel beam of the deformation section (20) through the lower flange connecting plate (25). The width of the first newly added lower wing plate (22) is greater than the width of the lower flange. The width of the lower flange of the steel beam of the deformation section (20), the first newly added upper wing plate (21) is parallel to the first newly added lower wing plate (22), the top end of the first newly added vertical web (23) is welded to the first newly added upper wing plate (21), and the other end is welded to the first newly added lower wing plate (22), the top end of the newly added inclined web (24) is welded to the first newly added upper wing plate (21), and the other end is welded to the first newly added lower wing plate (22), and is connected to the lower flange of the steel beam of the deformation section (20).

3. The method for reinforcing a twisted and deformed I-beam according to claim 2, characterized in that: When the width of the first newly added lower wing plate (22) is greater than or equal to 350 mm, the number of the lower flange connecting plates (25) is at least two, and the distance between the first newly added lower wing plate (22) and the welded portion of the steel beam lower flange of the deformation section (20) and at least two of the lower flange connecting plates (25) is no greater than 200 mm.

4. The method for reinforcing a twisted and deformed I-beam according to claim 2, wherein: The second cross-section enlarged reinforcement structure comprises a second newly added upper wing plate (31), a second newly added lower wing plate (32), and a second newly added vertical web plate (33); The second newly added upper wing plate (31) is welded to the bottom surface of the upper flange of the steel beam of the undeformed section (30) and is distributed on both sides of the steel beam web of the undeformed section (30). The second newly added lower wing plate (32) is welded to the bottom surface of the lower flange of the steel beam of the undeformed section (30). The second newly added vertical web (33) is arranged on both sides of the steel beam web of the undeformed section (30), with its top end welded to the second newly added upper wing plate (31) and its bottom end welded to the lower flange of the steel beam of the undeformed section (30). The second newly added upper wing plate (31) is parallel to the second newly added lower wing plate (32).

5. The method for reinforcing a twisted and deformed I-beam according to claim 4, characterized in that: The thickness of the upper flange and the lower flange of the twisted and deformed I-beam (10) is defined as H1, and the thickness of the first newly added upper wing plate (21), the first newly added lower wing plate (22), the second newly added upper wing plate (31), and the second newly added lower wing plate (32) is defined as h1, then H1 and h1 satisfy h1≤H1.

6. The method for reinforcing a twisted and deformed I-beam according to claim 4, characterized in that: The thickness of the web of the twisted and deformed I-beam (10) is defined as H2, and the thickness of the first newly added vertical web (23), the second newly added vertical web (33), and the newly added inclined web (24) is defined as h2, then H2 and h2 satisfy h2≤H2.

7. The method for reinforcing a twisted and deformed I-beam according to claim 4, characterized in that: A plurality of second stiffening plates (60) are arranged at first distance intervals on both sides of the webs of the deformed section (20) and the undeformed section (30); the first stiffening plate (40) and the second stiffening plate (60) located in the deformed section (20) are closely attached to the first newly added lower wing plate (22) and the upper flange, web and lower flange of the steel beam of the deformed section (20), and pass through the first newly added vertical web (23) or the newly added inclined web (24); the first stiffening plate (40) and the second stiffening plate (60) located in the undeformed section (30) are closely attached to the upper flange, web and lower flange of the steel beam of the undeformed section (30), and pass through the second newly added vertical web (33).

8. The method for reinforcing a twisted and deformed I-beam according to claim 7, characterized in that: The first distance is 500 mm.

9. The method for reinforcing a twisted and deformed I-beam according to claim 1, wherein: The first stiffening plate (40) is laterally protruded with a connecting block, the lateral tie rod (50) is connected to the first stiffening plate (40) via the connecting block, and the other end of the lateral tie rod (50) is connected to the top end of the steel beam adjacent to the twisted and deformed I-beam (10).

10. The method for reinforcing a twisted and deformed I-beam according to claim 1, characterized in that: The length of the first undeformed segment is defined as D, and the length of the second undeformed segment is defined as d. Then, D and d satisfy D / 3≤d≤D / 2.

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