CN216304454U

CN216304454U - UHPC cladding restoration structure of corrosion steel bridge girder tip

Info

Publication number: CN216304454U
Application number: CN202122860633.8U
Authority: CN
Inventors: 李兆超; 张哲�; 彭勃; 伍梦晴
Original assignee: Hunan University of Technology
Current assignee: Hunan University of Technology
Priority date: 2021-11-19
Filing date: 2021-11-19
Publication date: 2022-04-15
Anticipated expiration: 2031-11-19

Abstract

A UHPC (ultra high performance concrete) coated repairing structure for rusted end parts of a steel bridge girder belongs to the technical field of bridge repairing structures and is characterized in that the steel bridge girder is connected with UHPC coated sections through shear connectors, each UHPC coated section is composed of an UHPC web plate and an UHPC flange plate, and the UHPC coated sections are coated outside a rusted area at the end parts of the steel bridge girder. The degraded section of the end part of the rusted steel bridge girder is repaired by adopting the UHPC, so that on one hand, the end part of the steel bridge girder can be effectively prevented from being rusted continuously due to the compact structure and the strong impermeability of the UHPC, and the durability of the steel bridge girder is improved; on the other hand, due to the fact that the UHPC is light and high in strength, the bearing capacity of the repaired steel main beam is improved by more than 20% compared with that of the steel main beam before the steel main beam is damaged, the vertical rigidity is improved by more than 60%, and the structural rigidity and the bearing capacity of the steel bridge main beam are greatly improved.

Description

UHPC cladding restoration structure of corrosion steel bridge girder tip

Technical Field

The utility model belongs to the technical field of bridge repairing structures, and particularly relates to a UHPC (ultra high performance concrete) cladding repairing structure for rusted steel bridge girder ends.

Background

Compared with the traditional concrete bridge, the steel beam bridge has the advantages of small self weight, large bearing capacity, strong spanning capacity, larger under-bridge clearance, lower bridge deck elevation, fine bridge structure appearance and good landscape effect, most of components are directly manufactured in factories and assembled on site, the installation speed is high, the construction period is short, the repair and the replacement are convenient, and the steel beam bridge is gradually popularized and used in China.

Although the steel beam bridge is simple and convenient to construct and attractive in appearance, some problems exist in the practical engineering application. The steel plate at the end part of the main girder of the steel bridge is washed and corroded by water flow leaked from the joint of the bridge deck for a long time, so that structural defects can be generated, the original mechanical property of the steel plate is lost, and the strength and the bearing capacity of the bridge are reduced.

The existing common method for repairing the end part of the main girder of the rusted steel bridge is to replace the original rusted steel with new steel, a large amount of manual welding between steel is needed, the field manual welding process is complex, a large amount of surface treatment work needs to be carried out before welding, the speed is slow, and the welded structure has poor ductility and a large amount of residual stress; moreover, the traditional paint coating can not effectively prevent the corrosion of the steel bridge girder and has poor durability, and the problems are to be solved in the repair work of the steel bridge girder.

For example, in a document published in northern traffic 2021 in 9 months entitled "analysis of diseases of existing steel structure bridges and research on protection techniques thereof", the "corrosion diseases of steel structure bridges cause great harm to safe and stable production and application of bridge construction projects"; also, for example, in the review document entitled "review of research and review of bridge engineering academia 2021" published in 2 months in 2021 of the journal, "the document at page 12" welding is used as a main connection mode of the current steel structure bridge, and the initial welding defect and the geometric discontinuity, stress concentration and local plasticization caused by the welding residual stress on the microscopic scale significantly reduce the fatigue extension life of the welding node.

SUMMERY OF THE UTILITY MODEL

Aiming at the technical problems, the utility model provides the UHPC cladding repair structure for rusting the end part of the steel bridge girder, which can effectively prevent the end part of the steel bridge girder from being corroded continuously on one hand, thereby improving the durability of the steel bridge girder; on the other hand, the bearing capacity of the repaired steel main beam is improved by more than 20 percent and the vertical rigidity is improved by more than 60 percent compared with the bearing capacity before the steel main beam is damaged, so that the structural rigidity and the bearing capacity of the steel bridge main beam are greatly improved.

The utility model adopts the following specific technical scheme:

a UHPC (ultra high performance concrete) coated repair structure for rusted end parts of a steel bridge girder is formed by connecting the steel bridge girder and UHPC coated sections through shear connectors, each UHPC coated section is composed of a UHPC web plate and a UHPC flange plate, and the UHPC coated sections are coated outside a rusted area at the end parts of the steel bridge girder.

Preferably, the length of the UHPC cladding section is larger than the rust length of the steel bridge girder.

Preferably, the height of the UHPC web plate exceeds the height of a rusted part of the steel bridge girder by 0.2m and is not lower than 1/3 of the total height of the steel bridge girder, and the thickness of the UHPC web plate is 2-5 cm.

Preferably, the UHPC flange plate is horseshoe-shaped, and the upper part of the horseshoe-shaped UHPC flange plate is a thickening transition area.

Preferably, the thickness of the UHPC flange plate is 5-7 cm, and the height of the variable thickness transition zone is 5-10 cm.

Preferably, the material of the UHPC coated segment adopts ultra-high performance fiber reinforced concrete or reactive powder concrete.

Preferably, the steel bridge girder is composed of a steel top plate, a steel web plate and a steel bottom plate from top to bottom respectively.

Preferably, the shear connectors are divided into transverse shear connectors and longitudinal shear connectors, the transverse shear connectors are arranged on the steel web plate at the end part of the steel bridge girder and embedded in the UHPC web plate, and the longitudinal shear connectors are arranged on the non-rusted area of the steel bottom plate at the end part of the steel bridge girder and embedded in the UHPC flange plate.

Preferably, the shear connector adopts a cylindrical head shear nail or/and a welding steel bar.

Preferably, the length of the transverse shear connector is less than the thickness of the UHPC web, and the length of the vertical shear connector is less than the height of the UHPC flange plate.

The utility model has the beneficial effects that:

(1) the degraded section at the end part of the steel bridge girder is wrapped by the UHPC with compact structure, light weight and high strength, the excellent impermeability, crack resistance, ultrahigh mechanical property and ductility of the UHPC are fully utilized, and the durability, structural rigidity and bearing capacity of the steel bridge girder can be greatly enhanced;

(2) the UHPC flange plate is provided with a horseshoe-shaped variable thickness area for transition, so that water flow aggregation can be prevented, stress concentration can be avoided, local pressure bearing of the bottom plate is assisted, and structural stability is improved;

(3) the shear connector is adopted to connect the steel bridge girder and the UHPC coated segment, so that the shearing resistance and structural integrity of the structure can be enhanced, the stress of each part of the structure is more reasonable, a large amount of manual welding work can be avoided, the residual stress is greatly reduced, and the structural safety is improved.

Drawings

FIG. 1 is a schematic diagram of a UHPC cladding repair structure of the end part of a main girder of a rusted steel bridge of the utility model;

fig. 2 is a sectional view taken along the line a-a in fig. 1.

1. A steel bridge girder; 11. a steel top plate; 12. a steel web; 13. a steel bottom plate; 2. UHPC coated segments; 21. A UHPC web; 22. a UHPC flange plate; 3. a shear connector; 31. a lateral shear connector; 32. A bottom surface shear connector; 4. an abutment; 5. provided is a bridge pier.

Detailed Description

The utility model is further illustrated by the following specific examples. The starting materials and methods employed in the examples of the present invention are those conventionally available in the market and conventionally used in the art, unless otherwise specified. The UHPC in the application is the Ultra-high Performance Concrete, which is called Ultra-high Performance Concrete for short in English.

Example 1

As shown in fig. 1 and 2, a bridge abutment 4 on a bridge pier 5 is connected with an end of a steel bridge girder 1, in the UHPC coated restoration structure of the end of the corroded steel bridge girder of the embodiment, the steel bridge girder 1 and a UHPC coated segment 2 are connected through a shear connector 3, the UHPC coated segment 2 is composed of a UHPC web 21 and a UHPC flange plate 22, the steel bridge girder 1 is composed of a steel top plate 11, a steel web 12 and a steel bottom plate 13 from top to bottom, the shear connector 3 is divided into a transverse shear connector and a longitudinal shear connector, and the UHPC coated segment 2 is coated outside a corrosion area at the end of the steel bridge girder 1 to compensate a cross section lost by corrosion at the end of the steel bridge girder 1. The UHPC coated section 2 is made of ultra-high performance fiber reinforced concrete and/or active powder concrete, which is prepared according to the maximum packing density principle, has low water-cement ratio and compact structure, and improves the strength and the deformation performance of the material by adding short and fine fibers (usually mainly steel fibers). Compared with common concrete and high-strength concrete, the ultra-high performance concrete has the advantages of ultra-high mechanical property, ultra-high durability, excellent waterproofness, and adjustable matching and designability facing to performance requirements.

The length of the UHPC cladding section 2 is larger than the rusted length of the steel bridge girder 1, the height of the UHPC web plate 21 exceeds the height of the rusted part of the steel bridge girder by 0.2m and is not lower than 1/3 of the total height of the steel bridge girder 1, and the thickness of the UHPC web plate 21 is 2-5 cm. The thickness of the UHPC flange plate 22 is 5-7 cm, the cross section is designed to be horseshoe-shaped, the upper part of the horseshoe-shaped UHPC flange plate is a variable thickness transition area, the height of the variable thickness transition area is 5-10 cm, and the variable thickness transition area is used for preventing water flow from gathering and avoiding stress concentration and assisting the bottom plate to bear pressure locally.

The transverse shear connectors are arranged on the steel web plate 12 at the end part of the steel bridge girder 1 and are embedded in the UHPC web plate 21, and the longitudinal shear connectors are arranged on the non-rusted area of the steel bottom plate 13 at the end part of the steel bridge girder 1 and are embedded in the UHPC flange plate 22. The shear connector 3 adopts cylindrical shear nails or/and welded steel bars, the length of the transverse shear connector is less than the thickness of the UHPC web plate 21, the length of the longitudinal shear connector is less than the height of the UHPC flange plate 22, the installation of the shear connector 3 can enhance the shear resistance and structural integrity of the structure, and the stress of each part of the structure is more reasonable.

The UHPC coated segment 2 has excellent crack resistance and impermeability, protects the end part of the steel bridge girder 1 from being corroded by corrosive substances, and improves the durability of the steel bridge; the excellent crack resistance is represented by tensile strain hardening performance and tensile strain level exceedingWhen the crack width of the UHPC coated segment 2 is over 0.2 percent, the crack width of the UHPC coated segment 2 is not more than 0.05 mm; excellent impermeability is that the impermeability grade is not less than P35, and the permeability coefficient of chloride ion is less than 2.0 x 10^-14m²And/s, the carbonization depth is not more than 0.5 mm/year in natural environment. The UHPC coated segment 2 also has excellent mechanical properties so as to strengthen the structural rigidity and the bearing capacity of the steel girder 1 after UHPC coating repair; the mechanical properties are that the compressive strength is not lower than 130MPa, and the tensile strength is not lower than 7.0 MPa; the bearing capacity of the repaired steel bridge is improved by more than 20 percent compared with the bearing capacity before the steel bridge is damaged, the integral rigidity is improved by more than 5 percent compared with the bearing capacity before the steel bridge is damaged, and the vertical rigidity is improved by more than 60 percent compared with the bearing capacity before the steel bridge is damaged.

In the UHPC cladding repair structure design in this embodiment, the same standard design is adopted for a typical bridge type, and individual design and customized design shapes for specific projects are avoided.

Example 2

The UHPC cladding restoration structure of corrosion steel bridge girder tip of this embodiment is connected through shear force connecting piece 3 by steel bridge girder 1 and UHPC cladding section 2, UHPC cladding section 2 comprises UHPC web 21 and UHPC flange board 22, steel bridge girder 1 is from last to down respectively by steel roof 11, steel web 12 and steel bottom plate 13 constitution, shear force connecting piece 3 divide into horizontal shear force connecting piece and vertical shear force connecting piece, UHPC cladding section 2 cladding compensates the cross-section that steel bridge girder 1 tip lost because of the corrosion in the corrosion region outside of steel bridge girder 1 tip. The UHPC coated section 2 is made of ultra-high performance fiber reinforced concrete and/or active powder concrete, which is prepared according to the maximum packing density principle, has low water-cement ratio and compact structure, and improves the strength and the deformation performance of the material by adding short and fine fibers (usually mainly steel fibers). Compared with common concrete and high-strength concrete, the ultra-high performance concrete has the advantages of ultra-high mechanical property, ultra-high durability, excellent waterproofness, and adjustable matching and designability facing to performance requirements.

The UHPC coated segment 2 has excellent crack resistance and impermeability, protects the end part of the steel bridge girder 1 from being corroded by corrosive substances, and improves the durability of the steel bridge; the excellent crack resistance is represented by tensile strain hardening performance, and when the tensile strain level exceeds 0.2%, the crack width of the UHPC coated segment 2 is not more than 0.05 mm; excellent impermeability is that the impermeability grade is not less than P35, and the permeability coefficient of chloride ion is less than 2.0 x 10^-14m²And/s, the carbonization depth is not more than 0.5 mm/year in natural environment. The UHPC coated segment 2 also has excellent mechanical properties so as to strengthen the structural rigidity and the bearing capacity of the steel girder 1 after UHPC coating repair; the mechanical properties are that the compressive strength is not lower than 130MPa, and the tensile strength is not lower than 7.0 MPa; the bearing capacity of the repaired steel bridge is improved by more than 20 percent compared with the bearing capacity before the steel bridge is damaged, the integral rigidity is improved by more than 5 percent compared with the bearing capacity before the steel bridge is damaged, and the vertical rigidity is improved by more than 60 percent compared with the bearing capacity before the steel bridge is damaged.

In the UHPC cladding repair structure at the end part of the rusted steel bridge girder, the height of an I-shaped steel bridge girder 1 is 528mm, the thickness of the I-shaped steel bridge girder is 14mm, the length of an UHPC cladding section 2 is 660mm, the height of the UHPC cladding section is 230mm, the thickness of an UHPC web plate 21 is 45mm, the thickness of an UHPC flange plate 22 is 73mm, the height of the UHPC flange plate is 50mm, and the width of a variable thickness transition area between the UHPC web plate 21 and the UHPC flange plate 22 is 50 mm. The shear connector 3 has a diameter of 10mm and a length of 30mm, and the UHPC clad segment 2 provides the shear connector 3 with a protective layer having a thickness of 15 mm.

The UHPC coated section 2 is poured by ultra-high performance fiber reinforced concrete, and the shear connector 3 is an ultra-short cylindrical head shear nail.

Example 3

The difference between the embodiment and the embodiment 2 is that the UHPC coated segment 2 is poured by ultra-high performance fiber reinforced concrete, and the shear connector 3 is welded steel bars.

Example 4

A construction method for UHPC cladding repair of a rusted steel bridge girder end part comprises the following steps:

and S1, removing the rust on the end part of the rusted steel bridge girder and locally blasting sand to remove rust. Compared with the traditional repairing method, the method has the advantages that a large amount of complex surface treatment work can be reduced in the construction process, the complex lead elimination work is avoided, and the lead-containing waste is prevented from polluting the environment.

S2, welding shear nails or constructing other shear connectors on the steel web 12 and the steel bottom plate 13 of the steel bridge girder;

s3, manufacturing a UHPC coated segment template, embedding the shear connector 3 and the end part of the steel bridge girder 1 in the UHPC coated segment 2 in a coating manner, pouring UHPC material to enable the UHPC coated repair structure and the steel bridge girder 1 to form a whole, and removing the template after the UHPC coated segment 2 is maintained to finish construction.

The construction process can avoid jacking and ground stress rechecking, has lower requirements on the terrain and foundation bearing capacity around the bridge to be repaired and wider application range, and can greatly shorten the construction period and reduce the project cost.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A UHPC coating repair structure for rusted end portions of a steel bridge girder is characterized in that the steel bridge girder is connected with UHPC coating segments through shear connectors, each UHPC coating segment is composed of a UHPC web plate and a UHPC flange plate, and the UHPC coating segments are coated outside a rusted area at the end portions of the steel bridge girder.

2. The rusted steel bridge girder end UHPC clad repair structure according to claim 1, wherein the length of the UHPC clad section is greater than the rusted length of the steel bridge girder.

3. The UHPC cladding repair structure of the rusted steel bridge girder end part according to claim 1, wherein the height of the UHPC web plate exceeds the height of a rusted part of the steel bridge girder by 0.2m and is not lower than 1/3 of the total height of the steel bridge girder, and the thickness of the UHPC web plate is 2-5 cm.

4. The UHPC cladding repair structure of corrosion steel bridge girder tip of claim 1, characterized in that, the UHPC flange board is the shape of a horseshoe, and the upper portion of shape of a horseshoe UHPC flange board is the thickness transition district.

5. The UHPC cladding repair structure of the rusted steel bridge girder end part according to claim 4, wherein the thickness of the UHPC flange plate is 5-7 cm, and the height of the variable thickness transition zone is 5-10 cm.

6. The rusted steel bridge girder end UHPC clad repair structure of claim 2, wherein the material of the UHPC clad section is ultra-high performance fiber reinforced concrete or reactive powder concrete.

7. The UHPC clad-repaired structure at the end part of the rusted steel bridge girder of claim 1, wherein the steel bridge girder consists of a steel top plate, a steel web plate and a steel bottom plate from top to bottom respectively.

8. The UHPC clad repair structure of the rusted steel bridge girder end part according to claim 1, wherein the shear connectors are divided into a transverse shear connector and a longitudinal shear connector, the transverse shear connector is arranged on the steel web plate of the steel bridge girder end part and is embedded in the UHPC web plate, and the longitudinal shear connector is arranged on the non-rusted area of the steel bottom plate of the steel bridge girder end part and is embedded in the UHPC flange plate.

9. The UHPC cladding repair structure of the rusted steel bridge girder end part according to claim 8, characterized in that the shear connector adopts a cylindrical head shear nail or/and a welded steel bar.

10. The UHPC clad repair structure of the rusted steel bridge girder end part according to claim 8, wherein the length of the transverse shear connector is less than the thickness of the UHPC web plate, and the length of the longitudinal shear connector is less than the height of the UHPC flange plate.