A mesh steel frame cage for small box beams

Abstract

The present invention relates to a meshed steel skeleton cage for a small box girder, characterized in that the meshed steel skeleton cage is constructed by modular steel meshes, each modular steel mesh is composed of steel bars in two different directions, namely, transverse steel bars and longitudinal steel bars, and the plane intersection angle of the longitudinal steel bars and the transverse steel bars is 30-150°. Compared with the traditional steel skeleton cage for bridge components, the present invention has subversive significance and can have a revolutionary impact on the design and construction of bridge structures. The present invention can effectively reduce the operation time, on-site working time and labor intensity of steel engineering, improve work efficiency, reduce energy consumption and environmental pollution, greatly improve the specialization and industrialization of steel engineering, have good economic benefits, scientific and technological benefits, environmental benefits and social benefits, and is worthy of promotion and application.

Description

Technical Field

[0001] The invention relates to a meshed steel bar skeleton cage for bridge components, and in particular to a meshed steel bar skeleton cage for small box beams and a design and construction method thereof.

[0002] The invention is automatically processed by special equipment controlled by a program, and can replace the reinforcement form in the current structure, effectively reducing the operation time, on-site working time and labor intensity of the reinforcement engineering, improving work efficiency, reducing energy consumption and environmental pollution, and greatly improving the specialization and industrialization of the reinforcement engineering. The invention belongs to the field of civil engineering technology. Background Art

[0003] At present, the steel bars in the structure are mainly processed by bending single steel bars, assembling them and tying them at the intersection to form a steel cage, which is then poured together with concrete to form a reinforced concrete structure. However, the above working method leads to heavy workload, poor working conditions, low work efficiency, and great environmental pollution for workers. In addition, due to the uneven technical level of workers, omissions are prone to occur during the operation, resulting in the construction quality of the steel bars not being guaranteed.

[0004] like Figure 1 As shown, the conventional small box girder reinforcement skeleton cage usually includes bottom plate closed ring reinforcement 11, bottom plate longitudinal reinforcement 12, web plate closed stirrups 13, web plate longitudinal reinforcement 14, top plate closed ring reinforcement 15, top plate longitudinal reinforcement 16, chamfered and axilla reinforcement 17. The general construction method is to first tie the bottom plate closed ring reinforcement and the bottom plate longitudinal reinforcement into a bottom plate reinforcement skeleton, and then tie the web plate closed stirrups and web plate longitudinal reinforcement on both sides of the bottom plate reinforcement skeleton to form a web plate reinforcement skeleton, and then tie the top plate closed ring reinforcement and the top plate longitudinal reinforcement on the upper part of the web plate reinforcement skeleton on both sides to form a top plate reinforcement skeleton, and finally tie the chamfered and axilla reinforcement to form the final small box girder reinforcement skeleton cage, which has the disadvantages of long on-site construction time, heavy workload for workers, poor working conditions, low work efficiency, and no guarantee of construction quality. Summary of the invention

[0005] The purpose of the present invention is to provide a mesh steel skeleton cage for small box girders, which can replace the current reinforcement form in bridge structures, effectively reduce the operation time of steel engineering, on-site working time and labor intensity, improve work efficiency, reduce energy consumption and environmental pollution, greatly improve the specialization and industrialization of steel engineering, and have good economic benefits, scientific and technological benefits, environmental benefits and social benefits.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a meshed steel skeleton cage for a small box girder, characterized in that the meshed steel skeleton cage is constructed by modular steel meshes, each modular steel mesh is composed of steel bars in two different directions, namely, transverse steel bars and longitudinal steel bars, and the plane intersection angle of the longitudinal steel bars and the transverse steel bars is 30~150°.

[0007] Furthermore, the modular steel mesh includes a first steel mesh, a second steel mesh, a third steel mesh, a fourth steel mesh, a fifth steel mesh and a sixth steel mesh, wherein the sixth steel mesh is a plane mesh corresponding to the upper part of the small box girder top plate; the main structure of the first steel mesh is a U-shaped structure, and the U-shaped structure includes a bottom surface corresponding to the lower part of the small box girder bottom plate, and both sides of the bottom surface are bent obliquely upward to form side surfaces corresponding to the outer side of the web, and the tops of the side surfaces on both sides are bent to both sides respectively to form horizontal bending portions corresponding to the sixth steel mesh; the main structure of the second steel mesh is a horizontal plane structure, and both ends of the second steel mesh are bent obliquely upward to form oblique bending portions matching the side surfaces of the first steel mesh; the main body of the third steel mesh is a U-shaped structure corresponding to the inner side of the web Inclined structure, the bottom of the third steel mesh is bent inwardly to form a lower bending portion matching the bottom surface of the first steel mesh, and the top of the third steel mesh is bent outwardly to form an upper bending portion corresponding to the sixth steel mesh; the fourth steel mesh includes a top surface corresponding to the lower part of the top plate, and both sides of the top surface are bent obliquely downward to form inner chamfered and armpit inclined surfaces corresponding to the inner chamfered and armpit, and the bottoms of the inner chamfered and armpit inclined surfaces on both sides are bent obliquely downward respectively to form a lower bending portion corresponding to the side surface of the first steel mesh; the main body of the fifth steel mesh is an outer chamfered and armpit surface corresponding to the outer chamfered and armpit, the outer end of the outer chamfered and armpit surface is bent to form an outer bending portion corresponding to the bottom of the top plate, and the inner end of the outer chamfered and armpit surface is bent to form an inner bending portion corresponding to the inclined structure of the third steel mesh.

[0008] Furthermore, the bottom surface of the first steel mesh is located at the lower part of the bottom plate of the small box beam, and the side surfaces of the first steel mesh are located on the outside of the web; the second steel mesh is located in the U-shaped structure of the first steel mesh, and the horizontal plane of the second steel mesh is located above the bottom surface of the first steel mesh and is located at the upper part of the bottom plate of the small box beam, and the oblique bending parts at both ends of the second steel mesh are respectively attached to the inner sides of the side surfaces of the first steel mesh; the inclined surface structure of the first third steel mesh is located in the first steel mesh and is located on the inner side of the web position on one side of the small box beam, the lower bending part of the first third steel mesh is attached above the first steel mesh, the inclined surface structure of the second third steel mesh is located in the first steel mesh and is located on the inner side of the web position on the other side of the small box beam, and the second third steel mesh The lower bending part of the sheet is attached to the first steel mesh; the fourth steel mesh is located in the U-shaped structure of the first steel mesh, the top surface of the fourth steel mesh is at the lower part of the small box girder top plate position, and the lower bending parts on both sides of the fourth steel mesh are respectively attached to the inner sides of the side surfaces on both sides of the first steel mesh; two fifth steel meshes are arranged at the outer chamfer and armpit position of the small box girder, the outer chamfer and armpit inclined surface of the fifth steel mesh is located at the outer chamfer and armpit position of the small box girder, the outer bending part of the fifth steel mesh is located at the lower part of the small box girder top plate position, and the inner bending part of the fifth steel mesh is attached to the outer side of the corresponding third steel mesh inclined surface structure; the sixth steel mesh is located at the upper part of the small box girder top plate position, and the horizontal bending part of the first steel mesh and the upper bending part of the third steel mesh are both attached to the bottom of the sixth steel mesh.

[0009] Furthermore, the first steel mesh may be formed by splicing two symmetrically arranged left and right pieces, or may be integrally processed at one time.

[0010] Another object of the present invention is to provide a construction method for a mesh steel skeleton cage for a small box girder, which can replace the current reinforcement form in the bridge structure, effectively reduce the steel engineering operation time, on-site working time and labor intensity, improve work efficiency, reduce energy consumption and environmental pollution, greatly improve the specialization and industrialization of steel engineering, and have good economic benefits, scientific and technological benefits, environmental benefits and social benefits.

[0011] In order to achieve the above object, the technical solution of the present invention is as follows: a construction method of a mesh steel frame cage for a small box girder, characterized in that the construction method comprises:

[0012] A. Process the first steel mesh, the second steel mesh, the third steel mesh, the fourth steel mesh, the fifth steel mesh and the sixth steel mesh, wherein the sixth steel mesh is a plane mesh corresponding to the upper part of the small box girder top plate; the main structure of the first steel mesh is a U-shaped structure, and the U-shaped structure includes a bottom surface corresponding to the lower part of the bottom plate of the small box girder, and the two sides of the bottom surface are bent obliquely upward to form side surfaces corresponding to the outer side of the web, and the tops of the two side surfaces are bent toward both sides respectively to form horizontal bending portions corresponding to the sixth steel mesh; the main structure of the second steel mesh is a horizontal plane structure, and the two ends of the second steel mesh are bent obliquely upward to form oblique bending portions matching the side surfaces of the first steel mesh; the main body of the third steel mesh is an inclined surface structure corresponding to the inner side of the web, The bottom of the third steel mesh is bent inwardly to form a lower bending portion that matches the bottom surface of the first steel mesh, and the top of the third steel mesh is bent outwardly to form an upper bending portion corresponding to the sixth steel mesh; the fourth steel mesh includes a top surface corresponding to the lower portion of the top plate, and both sides of the top surface are bent obliquely downward to form inner chamfered and axillary inclined surfaces corresponding to the inner chamfered and axillary surfaces, and the bottoms of the inner chamfered and axillary inclined surfaces on both sides are bent obliquely downward to form a lower bending portion corresponding to the side surface of the first steel mesh; the main body of the fifth steel mesh is an outer chamfered and axillary surface corresponding to the outer chamfered and axillary surface, and the outer end of the outer chamfered and axillary surface is bent to form an outer bending portion corresponding to the bottom of the top plate, and the inner end of the outer chamfered and axillary surface is bent to form an inner bending portion corresponding to the inclined surface structure of the third steel mesh;

[0013] B. First set up the outer formwork, install the first steel mesh on the outer formwork, install the second steel mesh inside the first steel mesh, then install a third steel mesh on both sides of the inside of the first steel mesh, then set up the inner formwork, and then install the fourth steel mesh and two fifth steel meshes in sequence, and finally install the sixth steel mesh. The steel bars of each mesh and the mesh steel bars and the formwork are positioned and temporarily fixed by means of pads, bracket steel bars, etc., and finally a mesh steel skeleton cage of a small box girder structure is formed.

[0014] Another object of the present invention is to provide a design method for a meshed steel skeleton cage for a small box girder. The designed meshed steel skeleton cage can replace the current reinforcement form in the bridge structure, effectively reduce the steel engineering operation time, on-site working time and labor intensity, improve work efficiency, reduce energy consumption and environmental pollution, greatly improve the specialization and industrialization of steel engineering, and have good economic benefits, scientific and technological benefits, environmental benefits and social benefits.

[0015] In order to achieve the above object, the technical solution of the present invention is as follows: a design method for a mesh steel frame cage for a small box girder, characterized in that the design method comprises:

[0016] Firstly, the closed ring reinforcement of the top and bottom plates and the closed stirrups of the web are discretized. The top and bottom plate reinforcements are discretized into upper and lower layers of reinforcement, respectively, and the web is discretized into inner and outer reinforcements.

[0017] Then, the lower layer of top plate steel bars are integrated with the bent steel bars at the chamfered corners and the armpits, the upper layer of bottom plate steel bars are integrated with the bent steel bars at the chamfered corners and the armpits, and the outer vertical steel bars of the web and the lower layer of transverse steel bars of the bottom plate are integrated into an integrated U-shaped bar.

[0018] Finally, meshed steel bars are formed, wherein the first steel mesh of a U-shaped structure is formed by the outer vertical steel bars of the web and the lower steel bars of the bottom plate, as well as the longitudinal steel bars of the web and the longitudinal steel bars of the bottom plate that match them; the second steel mesh is formed by the upper transverse steel bars of the bottom plate and the longitudinal steel bars that match them; the third steel mesh is formed by the inner vertical steel bars of the web and the longitudinal steel bars of the web that match them; the fourth steel mesh is formed by the middle part of the lower steel bars of the top plate and the inner chamfered and armpit bent steel bars and the longitudinal steel bars that match them; the fifth steel mesh is formed by the outer part of the lower steel bars of the top plate and the outer chamfered and armpit bent steel bars and the longitudinal steel bars that match them; and the sixth steel mesh is formed by the upper steel bars of the top plate and the longitudinal steel bars that match them.

[0019] The mesh steel skeleton cage of the present invention is entirely composed of modular steel mesh pieces, which are assembled through automated installation equipment. Compared with traditional steel skeleton cages, it greatly improves work efficiency and has subversive significance.

[0020] The mesh steel cage can replace the reinforcement form in the current structure. For example, the steel cage in the current small box girder structure is mainly formed by bending a single steel bar, assembling it and tying it at the intersection, and the production cycle of a small box girder steel cage is about 20 working days; if the method of the present invention is adopted, the corresponding finished steel bars can be purchased according to the design requirements, and then they can be automatically processed into a whole steel mesh by special processing and production equipment in the factory, and finally hoisting machinery is used to directly install it in place in a certain order to form a mesh steel cage, and the production cycle of a small box girder steel cage is about 5 working days.

[0021] The mesh steel cage, its design, production, installation method and its application in bridge structure are breakthroughs in existing traditional concepts and ideas, and are the results of analysis and verification through a large number of theoretical and experimental studies, including full-scale experimental research on bridge structures using mesh steel cages, experimental research on mesh steel cage technology, experimental research on bridge components using mesh steel cages, and spatial finite element numerical simulation research. The above theoretical analysis and experimental research have verified that the bending, shear and torsion resistance of bridge structures using mesh steel cages and their industrialized processing and production methods can meet relevant specifications and actual application requirements.

[0022] The application of the mesh steel skeleton cage in the bridge structure can have a revolutionary impact on the design and construction of the bridge structure, greatly improve the construction efficiency, and provide strong technical support for the ultimate realization of the industrialized and information-based construction method of the bridge structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the cross section of the existing traditional small box girder structure steel frame cage;

[0024] Figure 2 A schematic cross-sectional view of a mesh steel frame cage of a small box beam structure using the present invention;

[0025] Figure 3 This is a schematic diagram of the cross section of the No. 1 steel mesh in the web of the small box girder;

[0026] Figure 4 This is a schematic diagram of the cross section of the No. 2 steel mesh in the web of the small box girder;

[0027] Figure 5 This is a schematic diagram of the cross section of the No. 3 steel mesh in the bottom plate of the small box beam;

[0028] Figure 6 This is a schematic diagram of the cross section of the No. 4 steel mesh in the web of the small box girder;

[0029] Figure 7 This is a schematic diagram of the cross section of the No. 5 steel mesh in the top plate of the small box beam;

[0030] Figure 8 This is a schematic diagram of the cross section of the No. 6 steel mesh in the top plate of the small box beam;

[0031] Fig. 9 It is a three-dimensional spatial schematic diagram of a mesh steel bar skeleton cage of a small box girder structure using the present invention. DETAILED DESCRIPTION

[0032] The following combination Figures 1 to 9 , the present invention is further explained by describing a preferred specific embodiment in detail.

[0033] Figure 1This is a schematic diagram of the cross-section of the traditional small box girder structure steel cage. The steel cage is first processed by cutting and bending a single steel bar to form closed ring bars and web stirrups for the top and bottom plates, chamfered and bent steel bars at the axils, and longitudinal force-bearing steel bars and structural steel bars. Then they are manually positioned and installed, and finally tied at the intersection to form a steel cage. The traditional steel cage method is time-consuming and labor-intensive, and cannot be processed and installed using modern machinery. The installation accuracy is poor, and it is impossible to achieve industrialized and information-based production and processing methods. The production cycle of a small box girder steel cage is about 20 working days. On the other hand, the layout of the traditional steel cage also limits its application route for industrialized and information-based production methods. For example, the top and bottom plates use closed ring bars and the webs use stirrups, which form a bottleneck for its industrialized processing and installation.

[0034] In order to break through the bottleneck, we must take the design idea as the source and entry point, break through the existing traditional design ideas, and propose a set of design concepts and methods suitable for industrialized and information-based construction methods. First, the closed ring reinforcement of the top and bottom plates and the closed stirrups of the web are discretized. The top and bottom plate steel bars are discretized into two layers of upper and lower steel bars, and the web is discretized into two pieces of left and right steel bars; then they are partially integrated, the lower layer of the top plate steel bars are integrated with the bent steel bars at the chamfer and axilla, the upper layer of the bottom plate steel bars are integrated with the bent steel bars at the chamfer and axilla, and the outer vertical steel bars of the web and the lower horizontal steel bars of the bottom plate are integrated into an integrated U-shaped bar. Finally, meshed steel bars are formed, among which No. 1 steel mesh 1 of U-shaped structure is formed by the outer vertical steel bars of the web and the lower steel bars of the bottom plate, as well as the longitudinal steel bars of the web and the longitudinal steel bars of the bottom plate matched therewith; No. 2 steel mesh 2 is formed by the upper transverse steel bars of the bottom plate and the longitudinal steel bars matched therewith; No. 3 steel mesh 3 is formed by the inner vertical steel bars of the web and the longitudinal steel bars of the web matched therewith; No. 4 steel mesh 4 is formed by the middle part of the lower steel bars of the top plate and the inner chamfers and the bent steel bars at the armpits and the longitudinal steel bars matched therewith; No. 5 steel mesh 5 is formed by the outer part of the lower steel bars of the top plate and the outer chamfers and the bent steel bars at the armpits and the longitudinal steel bars matched therewith; No. 6 steel mesh 6 is formed by the upper steel bars of the top plate and the longitudinal steel bars matched therewith. The above-mentioned breakthrough in the existing traditional steel cage design is the result of a lot of theoretical research and experimental research, which has been analyzed and verified, and finally formed as follows. Figure 2 The schematic diagram of the cross-section of the mesh steel frame cage of the small box girder structure is shown.

[0035] Figure 2 When the small box beam structure mesh steel frame cage is produced, it is first produced by program-controlled automatic processing production equipment. Figure 3 The No. 1 U-shaped steel mesh shown in FIG. Figure 4 The bottom plate No. 2 steel mesh 2 shown, Figure 5 The web plate No. 3 steel mesh 3 shown Figure 6 The top plate No. 4 steel mesh 4 shown, Figure 7The top plate No. 5 steel mesh 5 shown Figure 8 The top plate No. 6 steel mesh 6 is shown.

[0036] The steel meshes No. 1 to No. 6 are composed of longitudinal steel bars and transverse steel bars, and the plane intersection angle (α) of the longitudinal and transverse steel bars is 90°. During production, the automatic processing and production equipment is used to weld the intersection of the longitudinal and transverse steel bars to form a flat integral steel mesh. Among them, the steel meshes No. 1 to No. 5 are further bent as a whole to form a spatial integral steel mesh.

[0037] After completing the production of the mesh steel bars, use mechanical installation equipment to first set up the outer formwork and install the Figure 3 The No. 1 U-shaped steel mesh is then installed inside the No. 1 steel mesh. Figure 4 The bottom plate No. 2 steel mesh is shown, and then one piece is installed on each side of the inner side of the No. 1 steel mesh. Figure 5 The web No. 3 steel mesh is shown, and then the inner template is set up and then installed in sequence Figure 6 The top plate No. 4 steel mesh and two pieces Figure 7 The top plate No. 5 steel mesh is shown, and finally installed Figure 8 The No. 6 steel mesh of the top plate shown in the figure is positioned and temporarily fixed between each mesh steel bar and between the mesh steel bar and the formwork through pads, support steel bars and other measures, and finally forms a mesh steel skeleton cage of the small box girder structure. The production cycle of making a small box girder mesh steel skeleton cage in the above way is about 5 working days.

[0038] The steel mesh used to make the mesh steel skeleton cage is composed of steel bars in two different directions, namely, longitudinal steel bars and transverse steel bars. In the present embodiment, the plane intersection angle of the longitudinal steel bars and the transverse steel bars is 90°. Those skilled in the art should understand that the angle can also be any other angle, but generally speaking, the angle is preferably 30~150°.

[0039] The longitudinal and transverse steel bars of the steel mesh used to make the meshed steel skeleton cage can be stress-bearing steel bars or structural steel bars, and the steel meshes currently used in bridge structures are all used for structural steel bars.

[0040] The steel mesh used to make the mesh steel skeleton cage is not limited in the type and diameter of the steel bars, and can be used according to the design requirements. The steel bars can be various types of structural steel bars. The diameter of the steel bars generally ranges from 6mm to 50mm, and can be selected according to the needs in special cases. The diameter of the steel mesh currently used in bridge structures is no more than 12mm. The types of steel bars in the steel mesh include one or more of HPB235, HPB300, HRB335, HRBF335, HRB335E, HRBF335E, HRB400, HRBF400, HRB400E, HRBF400E, HRB500, HRBF500, HRB500E, HRBF500E, and RRB400.

[0041] The plane integral steel mesh can be further bent as a whole to form a spatial integral steel mesh through program-controlled processing and production equipment according to actual needs. The overall bending angle is generally ≥90° according to actual needs, and can also be any angle.

[0042] In summary, the mesh steel skeleton cage for bridge components proposed by the present invention is entirely assembled from modular steel meshes, and is manufactured in an industrialized and informationized manner throughout the process. It can completely replace the reinforcement form in the current structure, and compared with the traditional steel skeleton cage, it has a subversive significance, and can have a revolutionary impact on the design and construction of bridge structures, effectively reducing the operation time, on-site working time and labor intensity of steel engineering, improving work efficiency, reducing energy consumption and environmental pollution, greatly improving the specialization and industrialization of steel engineering, and having very good economic benefits, scientific and technological benefits, environmental benefits and social benefits.

[0043] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be regarded as limiting the present invention, and the protection scope of the present invention should be defined by the appended claims.

Claims

1. A mesh steel frame cage for small box beams, characterized in that The mesh steel skeleton cage is constructed by modular steel meshes, each modular steel mesh is composed of two steel bars in different directions, namely, transverse steel bars and longitudinal steel bars, the plane intersection angle of the longitudinal steel bars and the transverse steel bars is 30-150°, and the diameter range of the transverse steel bars and the longitudinal steel bars in the steel mesh is 6mm-50mm; The modular steel mesh comprises a first steel mesh, a second steel mesh, a third steel mesh, a fourth steel mesh, a fifth steel mesh and a sixth steel mesh, wherein the sixth steel mesh is a plane mesh corresponding to the upper part of the small box girder top plate; the main structure of the first steel mesh is a U-shaped structure, wherein the U-shaped structure comprises a bottom surface corresponding to the lower part of the small box girder bottom plate, the two sides of the bottom surface are bent obliquely upward to form a side surface corresponding to the outer side of the web, and the tops of the two side surfaces are bent to the two sides respectively to form a horizontal bending portion corresponding to the sixth steel mesh; The main structure of the second steel mesh is a horizontal plane structure, and the two ends of the second steel mesh are bent obliquely upward to form an oblique bending portion that matches the side of the first steel mesh; the main body of the third steel mesh is an inclined surface structure corresponding to the inner side of the web, the bottom of the third steel mesh is bent inward to form a lower bending portion that matches the bottom surface of the first steel mesh, and the top of the third steel mesh is bent outward to form an upper bending portion corresponding to the sixth steel mesh; the fourth steel mesh includes a corresponding lower portion of the top plate The top surface of the steel mesh sheet has two sides that are bent obliquely downward to form inner chamfered and armpit inclined surfaces corresponding to the inner chamfered and armpit surfaces, and the bottoms of the inner chamfered and armpit inclined surfaces on both sides are bent obliquely downward to form lower bending portions corresponding to the side surfaces of the first steel mesh sheet; the main body of the fifth steel mesh sheet is an outer chamfered and armpit surface corresponding to the outer chamfered and armpit surfaces, and the outer ends of the outer chamfered and armpit surfaces are bent to form an outer bending portion corresponding to the bottom of the top plate, and the inner ends of the outer chamfered and armpit surfaces are bent to form an inner bending portion corresponding to the inclined surface structure of the third steel mesh sheet.

2. The mesh steel skeleton cage according to claim 1, characterized in that: The bottom surface of the first steel mesh is located at the lower part of the bottom plate of the small box girder, and the side surfaces of the first steel mesh are located on the outer side of the web; the second steel mesh is located in the U-shaped structure of the first steel mesh, and the horizontal surface of the second steel mesh is located above the bottom surface of the first steel mesh and is located at the upper part of the bottom plate of the small box girder, and the oblique bending parts at both ends of the second steel mesh are respectively attached to the inner sides of the side surfaces of the first steel mesh; the inclined surface structure of the first third steel mesh is located in the first steel mesh and is located on the inner side of the web of one side of the small box girder, the lower bending part of the first third steel mesh is attached above the first steel mesh, and the inclined surface structure of the second third steel mesh is located in the first steel mesh , and is located on the inner side of the web position on the other side of the small box beam, the lower bending portion of the second third steel mesh is attached to the first steel mesh; the fourth steel mesh is located in the U-shaped structure of the first steel mesh, the top surface of the fourth steel mesh is located at the lower part of the top plate position of the small box beam, and the lower bending portions on both sides of the fourth steel mesh are respectively attached to the inner sides of the side surfaces on both sides of the first steel mesh; two fifth steel meshes are arranged at the outer chamfer plus arm position of the small box beam, the outer chamfer plus arm inclined surface of the fifth steel mesh is located at the outer chamfer plus arm position of the small box beam, the outer bending portion of the fifth steel mesh is located at the lower part of the top plate position of the small box beam, and the inner bending portion of the fifth steel mesh is attached to the outer side of the corresponding third steel mesh inclined surface structure; The sixth steel mesh is located above the top plate of the small box girder, and the horizontal bending portion of the first steel mesh and the upper bending portion of the third steel mesh are both attached to the bottom of the sixth steel mesh.

3. The mesh steel skeleton cage according to claim 1 or 2, characterized in that: The first steel mesh is formed by splicing two symmetrically arranged left and right pieces, or is processed as a whole at one time.

4. A construction method for a mesh steel frame cage for a small box girder, characterized in that The construction method comprises: A. Process the first steel mesh, the second steel mesh, the third steel mesh, the fourth steel mesh, the fifth steel mesh and the sixth steel mesh, wherein the sixth steel mesh is a plane mesh corresponding to the upper part of the small box girder top plate; the main structure of the first steel mesh is a U-shaped structure, and the U-shaped structure includes a bottom surface corresponding to the lower part of the bottom plate of the small box girder, and the two sides of the bottom surface are bent obliquely upward to form side surfaces corresponding to the outer side of the web, and the tops of the two side surfaces are bent toward both sides respectively to form horizontal bending portions corresponding to the sixth steel mesh; the main structure of the second steel mesh is a horizontal plane structure, and the two ends of the second steel mesh are bent obliquely upward to form oblique bending portions matching the side surfaces of the first steel mesh; the main body of the third steel mesh is an inclined surface structure corresponding to the inner side of the web, The bottom of the third steel mesh is bent inwardly to form a lower bending portion that matches the bottom surface of the first steel mesh, and the top of the third steel mesh is bent outwardly to form an upper bending portion corresponding to the sixth steel mesh; the fourth steel mesh includes a top surface corresponding to the lower portion of the top plate, and both sides of the top surface are bent obliquely downward to form inner chamfered and axillary inclined surfaces corresponding to the inner chamfered and axillary surfaces, and the bottoms of the inner chamfered and axillary inclined surfaces on both sides are bent obliquely downward to form a lower bending portion corresponding to the side surface of the first steel mesh; the main body of the fifth steel mesh is an outer chamfered and axillary surface corresponding to the outer chamfered and axillary surface, and the outer end of the outer chamfered and axillary surface is bent to form an outer bending portion corresponding to the bottom of the top plate, and the inner end of the outer chamfered and axillary surface is bent to form an inner bending portion corresponding to the inclined surface structure of the third steel mesh; B. First set up the outer formwork, install the first steel mesh on the outer formwork, install the second steel mesh inside the first steel mesh, then install a third steel mesh on both sides of the inside of the first steel mesh, then set up the inner formwork, and then install the fourth steel mesh and two fifth steel meshes in sequence, and finally install the sixth steel mesh. The steel bars of each mesh and the mesh steel bars and the formwork are positioned and temporarily fixed by pads and bracket steel bars, finally forming a mesh steel skeleton cage of a small box girder structure.

5. A design method for a mesh steel frame cage for a small box girder, characterized in that The design approach includes: Firstly, the closed ring reinforcement of the top and bottom plates and the closed stirrups of the web are discretized. The top and bottom plate reinforcements are discretized into upper and lower layers of reinforcement, respectively, and the web is discretized into inner and outer reinforcements. Then, the lower layer of top plate steel bars are integrated with the bent steel bars at the chamfered corners and the armpits, the upper layer of bottom plate steel bars are integrated with the bent steel bars at the chamfered corners and the armpits, and the outer vertical steel bars of the web and the lower layer of transverse steel bars of the bottom plate are integrated into an integrated U-shaped bar. Finally, meshed steel bars are formed, wherein the first steel mesh of a U-shaped structure is formed by the outer vertical steel bars of the web and the lower steel bars of the bottom plate, as well as the longitudinal steel bars of the web and the longitudinal steel bars of the bottom plate that match them; the second steel mesh is formed by the upper transverse steel bars of the bottom plate and the longitudinal steel bars that match them; the third steel mesh is formed by the inner vertical steel bars of the web and the longitudinal steel bars of the web that match them; the fourth steel mesh is formed by the middle part of the lower steel bars of the top plate and the inner chamfered and armpit bent steel bars and the longitudinal steel bars that match them; the fifth steel mesh is formed by the outer part of the lower steel bars of the top plate and the outer chamfered and armpit bent steel bars and the longitudinal steel bars that match them; and the sixth steel mesh is formed by the upper steel bars of the top plate and the longitudinal steel bars that match them.

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