Railway pier structure for improving durability of marine environment

Abstract

The utility model relates to the technical field of marine environment railway bridges, in particular to a railway bridge pier structure for improving the durability of a marine environment, which is characterized in that an anti-corrosion coating is arranged on the outer surface of a concrete member in the range of a water level variation area, a splash area and an atmospheric area; the anti-corrosion coating comprises fluorocarbon finish paint, an epoxy resin middle layer and epoxy seal primer; the steel bars, located in the range of the water level change area, of the pile foundation are epoxy coating steel bars; the steel bars, located in the water level change area and the splash area, of the bearing platform are epoxy coating steel bars. The steel bars, located in the water level change area and the splash area, of the pier body are epoxy coating steel bars. The periphery of the pile foundation is sleeved with a steel casing. The bridge pier has the advantages that the durability of the bridge pier in the marine environment is effectively improved, construction is convenient, and the effect is good; and the method has good technical economy, obvious social benefits and wide application prospects.

Description

Technical Field

[0001] The utility model relates to the technical field of marine environment railway bridges, in particular to a railway bridge pier structure capable of improving the durability in marine environment. Background Art

[0002] With the rapid development of railway construction in my country, the number of cross-sea bridges is increasing. However, the environment around cross-sea bridges is extremely harsh. In addition to bearing the live load of upper trains, they must also meet the durability requirements of strong winds, large waves, and highly corrosive environments. Under the long-term effects of harsh environments and loads, cross-sea bridges have experienced varying degrees of concrete protective layer peeling, steel bar corrosion and other problems within the design life. Their maintenance and reinforcement are extremely difficult and costly. Therefore, the durability design of cross-sea bridges has become a key research topic.

[0003] To improve the durability of bridges in marine environments, the commonly used method is to start with the building materials themselves to improve their corrosion resistance. For example, adding fly ash, silica fume, water reducer and other admixtures to concrete can effectively improve the durability, stability, density and impermeability of concrete. High-performance concrete is used to inhibit the diffusion of chloride ions, thereby improving durability. Engineering practice has proved that relying solely on improving the performance of the main structure building materials still results in a large number of bridge pier corrosion. Summary of the invention

[0004] The purpose of the utility model is to provide a railway pier structure with improved durability in the marine environment in accordance with the above-mentioned deficiencies of the prior art, and to improve the durability of the railway piers in the marine environment from three aspects: structural construction (protective layer thickness, crack width, widened top cap and elimination of hanging fence), building materials (high-performance concrete, epoxy-coated steel bars, anti-cracking steel mesh, rust inhibitors, etc.) and anti-corrosion measures (silane impregnation, permeable formwork cloth, etc.).

[0005] The purpose of this utility model is achieved by the following technical solutions:

[0006] A railway pier structure with improved durability in a marine environment, the railway pier structure comprising a plurality of concrete components, wherein the concrete components include a pile foundation, a cap, a pier body, a tray, and a cap, wherein the cap is supported on the pile foundation, the pier body is supported on the cap, the tray is arranged on the top of the pier body, and the cap is arranged on the top of the tray, the railway pier structure is in a marine environment, and the marine environment is divided into an atmospheric zone, a wave splash zone, a water level change zone, and an underwater zone from shallow to deep, and is characterized in that:

[0007] An anti-corrosion coating is provided on the outer surface of the concrete member within the water level fluctuation zone, the wave splash zone and the atmospheric zone, wherein the anti-corrosion coating comprises a fluorocarbon topcoat, an epoxy resin intermediate layer and an epoxy sealing primer;

[0008] The steel bars of the pile foundation located within the water level change zone are epoxy coated steel bars;

[0009] The steel bars of the said foundation located in the water level fluctuation zone and the wave splash zone are epoxy coated steel bars;

[0010] The steel bars in the pier body located in the water level fluctuation zone and the wave splash zone are epoxy coated steel bars;

[0011] The outer periphery of the pile foundation is provided with a steel casing.

[0012] The concrete of the cap and the pier body below the atmospheric zone, the grouting of the prestressed channel and the sealing mortar of the anchor end are added with steel bar rust inhibitor.

[0013] On the outer surface of the pier body and the outer surface of the cap, an anti-cracking steel mesh is arranged between the outermost layer of ordinary steel bars and the concrete surface.

[0014] The steel casing has a reinforced single layer epoxy powder coating.

[0015] The surface of the concrete member is impregnated with silane.

[0016] The concrete component adopts a permeable template cloth.

[0017] The utility model has the advantages of effectively improving the durability of bridge piers in marine environments, being convenient to construct and having excellent effects; having good technical and economic performance, obvious social benefits and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the elevation layout of the bridge pier of the utility model;

[0019] Figure 2 It is the plan layout diagram of the pier top cap of the utility model. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the features of the present invention and other related features through embodiments in conjunction with the accompanying drawings to facilitate understanding by technicians in the same industry:

[0021] like Figure 1-2 As shown, the marks 1-13 and AD in the figure respectively represent: pile foundation 1, abutment 2, pier body 3, tray 4, top cap 5, short column 6, enclosure 7, supporting cushion stone 8, groove 9, drainage hole 10, support 11, beam body 12, steel casing 13, underwater area A, water level change area B, splash zone C, and atmospheric area D.

[0022] Example: Figure 1 to Figure 2As shown, the railway bridge pier structure with improved marine environmental durability in this embodiment is determined according to the "Railway Concrete Structure Durability Design Code" and "Harbor Engineering Concrete Structure Anti-corrosion Technical Code", and the environmental action level and location division (atmospheric zone D, wave splash zone C, water level change zone B and underwater zone A) of the concrete structure at the bridge site are determined. The concrete of the beam body 12, the bridge pier body 3, the cap 2 and the pile foundation 1 are configured according to the marine durable concrete, the net protective layer thickness of the concrete structure steel bars is determined according to the durability code, reasonable structural construction measures are designed, and appropriate building materials are selected. Anti-corrosion measures (fluorocarbon topcoat, epoxy resin intermediate paint, epoxy sealing primer, etc.) are added to the outer surface of the pier and pile foundation concrete components within the water level change zone B, wave splash zone C and atmospheric zone D to improve the structural durability.

[0023] This embodiment improves the durability of railway piers in marine environment from three aspects: structural construction (protective layer thickness, crack width, widening the top cap and eliminating the hanging fence), building materials (high-performance concrete, epoxy-coated steel bars, anti-cracking steel mesh, rust inhibitors, etc.) and anti-corrosion measures (silane impregnation, permeable formwork cloth, etc.).

[0024] According to the provisions of the Technical Specification for Anti-corrosion of Concrete Structures in Seaport Engineering, the structure is divided into four zones: atmospheric zone D, splash zone C, water level change zone B and underwater zone A. Among them, the structures in the splash zone C and water level change zone B need to take enhanced anti-corrosion measures.

[0025] Pile foundation 1 is a reinforced concrete structure. The concrete grade is determined in combination with the environmental action grade at the bridge site. The steel bars within the water level change zone B are epoxy coated steel bars. The number of pile foundation 1 is designed in combination with the force calculation.

[0026] The pedestal 2 is a reinforced concrete structure. The concrete grade is determined based on the environmental action grade at the bridge site. The steel bars located in the water level change zone B and the splash zone C are epoxy-coated steel bars.

[0027] The pier body 3 is a reinforced concrete structure. The concrete grade is determined in combination with the environmental grade at the bridge site. The steel bars located in the water level change zone B and the wave splash zone C are epoxy coated steel bars. The pier body 3 has a round end shape.

[0028] The tray 4 is a reinforced concrete structure. The concrete grade is determined in combination with the environmental action grade at the bridge site. The tray 4 is a width transition section between the top cap 5 and the pier body 3 .

[0029] The top cap 5 is a reinforced concrete structure. The concrete grade is determined in combination with the environmental action grade at the bridge site. The top cap 5 must meet the bearing arrangement conditions and have an inspection channel for personnel to inspect the bearings. In order to reduce the workload of bridge pier maintenance, the conventional steel structure hanging fence is cancelled, and the top cap 5 is widened to set short columns 6. The daily inspection and maintenance of the bearings 11 are carried out on the widened top cap 5. The top cap 5 is rectangular in shape.

[0030] The short column 6 is a reinforced concrete structure, and the concrete grade is determined in combination with the environmental action grade at the bridge site. The short column is about 1m high, and a supporting cushion stone 8 is arranged on its top surface. The top caps 5 around the short column are provided with conditions for maintenance bearings 11.

[0031] The enclosure 7 is a reinforced concrete structure, and the concrete grade is determined in combination with the environmental action grade at the bridge site. It is arranged on the outer circle of the top cap 5, about 1m high, to protect personnel from checking the safety of the bearings.

[0032] The supporting cushion stone 8 is a reinforced concrete structure, the concrete grade is determined in combination with the environmental action grade at the bridge site, and a bearing 11 is arranged on the top surface thereof.

[0033] The groove 9 is arranged on the top of the short column 6 and between the supporting pad stones 8 , and the maintenance personnel can check the bearing around the short column 6 through the groove 9 .

[0034] The drain hole 10 is arranged on the top surface of the top cap 5, passes through the enclosure 7, and drains rainwater on the top surface of the top cap.

[0035] The support 11 is an important connecting structure between the beam body 12 and the bridge pier. The load of the beam body 12 is transferred to the bridge pier through the support 11.

[0036] The beam body 12 is a prestressed concrete structure. The concrete grade is determined in combination with the environmental action grade at the bridge site, and its span is arranged in combination with the on-site conditions.

[0037] The steel casing 13 is a steel structure, and the steel casing 13 is driven below the seabed surface before the construction of the pile foundation 1. The steel casing below the bottom of the cap is retained, and the steel casing is anti-corrosive with a reinforced single-layer epoxy powder coating (≥800μm). Its technical standards should comply with the relevant provisions of "Anti-corrosion Coating of Fusion-bonded Epoxy Powder Coating" (GB / T18593-2010) and "Technical Specification for Single-layer Fusion-bonded Epoxy Powder External Coating of Steel Pipelines" (SY / T 0315-2005). The coating range is from the bottom of the cap to 1m below the seabed scour line.

[0038] Table 1 Concrete structure and main building materials design principles

[0039]

[0040] Table 2 Additional anti-corrosion measures for concrete structures

[0041]

[0042] Note: The environmental action levels in this table need to be determined in combination with the specific marine environment.

[0043] In this embodiment, the performance requirements of the main anti-corrosion measures are as follows:

[0044] Fluorocarbon topcoat: It has self-cleaning function, and the self-cleaning characteristics should meet the requirements of the standard "Self-cleaning Paint for Building Exterior Surfaces" (GB / T31815-2015).

[0045] Silane impregnation: isooctyl triethoxy silane paste is recommended as the silane impregnation material, and the amount of silane should be no less than 400g / m 2 The quality requirements for silane impregnation materials are shown in Table 3.

[0046] Table 3 Quality requirements for silane impregnation materials

[0047]

[0048] After the concrete surface has been impregnated with silane for at least 7 days, a group of samples per 500m2 are taken on site to test the water absorption rate, immersion depth, and chloride absorption reduction effect.

[0049] Permeable formwork cloth: Meet the requirements of "Permeable formwork cloth for concrete engineering" (JTT 736-2015).

[0050] Epoxy rebar: Technical standards and construction should comply with the provisions of "Epoxy Resin Coated Rebar" (JG / T502-2016) and "Epoxy Coated Rebar for Reinforced Concrete" (GB / T25826-2022). Epoxy coated rebars shall not be connected by welding. HRB400 rebars with a diameter of <20mm may be connected by binding lap joints unless otherwise specified in the drawings. HRB400 rebars with a diameter of ≥20mm should be connected mechanically. The sleeve should use a special high-performance anti-corrosion coating connection sleeve, and the coating should comply with the provisions of "Anti-corrosion Coating of Fusion-bonded Epoxy Powder Coating" (GB / T18593-2010). High-performance repair materials should be used at the connection to repair the connection sleeve and other connection parts.

[0051] Steel bar rust inhibitor: Steel bar rust inhibitor is added to the concrete of the foundation and the pier body below the atmospheric zone, the grouting of the prestressed channel and the sealing mortar of the anchor end to improve the corrosion resistance of the concrete. The dosage and usage of the rust inhibitor shall be used in accordance with the recommendations of the corresponding products, and trial mixing and adaptability tests shall be carried out to meet the relevant provisions of the "Technical Code for Construction of Railway Concrete Engineering" (Q / CR9207-2017) and the "Technical Specification for the Application of Corrosion Resistance of Reinforced Concrete Rust Inhibitors" (GB / T33803-2017).

[0052] Anti-crack steel mesh: On the outer surface of the cast-in-place pier body and the outer surface of the cap, an anti-crack steel mesh is set between the outermost ordinary steel bar and the concrete surface. A bidirectional stainless steel mesh with a diameter of d=6mm (spacing of 10cm×10cm) is used. The net protective layer thickness of the mesh is 35mm, and the mesh is insulated from the internal ordinary steel bars. In order to ensure the anti-crack and anti-corrosion effect of the stainless steel mesh, arc welding or plasma welding is used.

[0053] After the marine environment piers are reasonably designed in terms of structural construction, building materials and anti-corrosion measures, the steel casing 13 is first installed on site using a construction trestle or ship, and the seawater in the abutment range is removed by a steel cofferdam. Then, the construction of the pile foundation 1, the abutment 2, and the pier body 3 is completed within the cofferdam. Finally, after the anti-corrosion measures on the outer surface of the structure are completed, the marine environment piers are formed.

[0054] Although the above embodiments have described the concepts and embodiments of the purpose of the utility model in detail with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and modifications can still be made to the utility model without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A railway pier structure with improved durability in marine environment, the railway pier structure comprising a plurality of concrete components, the concrete components comprising a pile foundation, a cap, a pier body, a tray, and a cap, wherein the cap is supported on the pile foundation, the pier body is supported on the cap, the tray is arranged on the top of the pier body, the cap is arranged on the top of the tray, the railway pier structure is in a marine environment, the marine environment is divided into an atmospheric zone, a splash zone, a water level change zone, and an underwater zone from shallow to deep, and is characterized in that: An anti-corrosion coating is provided on the outer surface of the concrete member within the water level fluctuation zone, the wave splash zone and the atmospheric zone, wherein the anti-corrosion coating comprises a fluorocarbon topcoat, an epoxy resin intermediate layer and an epoxy sealing primer; The steel bars of the pile foundation located within the water level change zone are epoxy coated steel bars; The steel bars of the said foundation located in the water level fluctuation zone and the wave splash zone are epoxy coated steel bars; The steel bars in the pier body located in the water level fluctuation zone and the wave splash zone are epoxy coated steel bars; The outer periphery of the pile foundation is provided with a steel casing.

2. The railway bridge pier structure with improved marine environment durability according to claim 1, characterized in that: The concrete of the cap and the pier body below the atmospheric zone, the grouting of the prestressed channel and the sealing mortar of the anchor end are added with steel bar rust inhibitor.

3. The railway bridge pier structure with improved marine environment durability according to claim 1, characterized in that: On the outer surface of the pier body and the outer surface of the cap, an anti-cracking steel mesh is arranged between the outermost layer of ordinary steel bars and the concrete surface.

4. The railway bridge pier structure with improved marine environment durability according to claim 1, characterized in that: The steel casing has a reinforced single layer epoxy powder coating.

5. The railway bridge pier structure with improved marine environment durability according to claim 1, characterized in that: The surface of the concrete member is impregnated with silane.

6. The railway bridge pier structure with improved marine environment durability according to claim 1, characterized in that: The concrete component adopts a permeable template cloth.

Images