CTRC-steel pipe semi-fabricated rc column facing marine environment and preparation method thereof

Abstract

The application discloses a CTRC-steel pipe semi-assembly type RC column for marine environment and a preparation method thereof, which comprises an inner steel pipe, a TRC shell, a core reinforced concrete layer and an external power supply; the inner steel pipe comprises a plurality of inner layer steel pipe assemblies which are coaxially stacked from top to bottom; each inner layer steel pipe assembly comprises an inner layer steel pipe segment and a connecting steel bar for connecting longitudinal steel bars; the TRC shell comprises a carbon fiber woven net capable of conducting electricity; a negative electrode of the external power supply is in electrically connected with the longitudinal steel bars, and a positive electrode is in electrically connected with each carbon fiber woven net. By utilizing the excellent electrical conductivity of the carbon fiber woven net in the TRC shell, the carbon fiber woven net bundle is used as an anode by using an impressed current cathodic protection method, and the internal steel framework is used as a cathode, so that the internal steel framework is protected, the durability of the whole structure is effectively improved, and the application is especially suitable for buildings, bridges and other engineering projects in corrosive environments such as marine environment, humid environment, saline land and saline-alkali land.

Description

Technical Field

[0001] This invention relates to the field of concrete technology, and in particular to a CTRC-steel pipe semi-assembled RC column for marine environments and its preparation method. Background Technology

[0002] Traditional concrete-filled steel tube columns effectively overcome the shortcomings of concrete's brittleness and poor ductility by placing the concrete under the constraint of an outer steel tube, and have advantages such as high load-bearing capacity and convenient construction, thus gaining widespread use. However, in marine environments, the outer steel tube of concrete-filled steel tube columns is susceptible to chloride corrosion, making durability issues particularly prominent. Therefore, there is an urgent need to develop concrete structures adapted to marine environments.

[0003] With the increasing environmental protection requirements for the civil engineering industry in recent years, the prices of materials such as steel and concrete have soared, making the cost of traditional solid concrete columns increasingly high. Conserving materials and related energy has become a major challenge for the civil engineering industry. Traditional steel-concrete composite columns are mainly solid-section columns, performing well as axially compressed members or compression-bending members with small load eccentricities. However, when solid steel-concrete composite columns are subjected to loads with large eccentricities, their bearing capacity is mainly controlled by bending stiffness. In this case, the concrete near the centroid of the cross-section contributes less to bending stiffness but increases the self-weight of the member. Therefore, using hollow sections can effectively reduce economic costs.

[0004] Traditional hollow concrete columns require extensive welding work when embedding the reinforcing cage, lack adequate construction space, and are difficult to construct. In addition, the production process requires the erection of formwork, and after pouring, the formwork needs to be removed. This process involves a large amount of formwork installation and removal work, a long service life, and requires a lot of personnel and equipment, making the process quite cumbersome.

[0005] In conclusion, it is necessary to invent a type of hollow concrete column that is suitable for marine corrosive environments, has good economic benefits, is easy to construct, has reliable quality, and meets industrialization requirements. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a CTRC-steel pipe semi-assembled RC column and its preparation method for marine environments. This CTRC-steel pipe semi-assembled RC column and its preparation method for marine environments uses an inner steel pipe and a TRC outer shell to compositely constrain the concrete of the core area. The inner steel pipe is quickly assembled using inner steel pipe assemblies to form the inner steel pipe and the prefabricated TRC outer shell. An impressed current cathodic protection method is also used, thereby solving problems such as insufficient structural durability, long construction period and excessive economic cost.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A CTRC-steel tube semi-assembled RC column for marine environments includes an inner steel tube, a TRC shell, a core reinforced concrete layer, and an external power supply.

[0009] The core reinforced concrete layer includes the core concrete column and the longitudinal reinforcement embedded in the core concrete column.

[0010] The inner steel pipe consists of several inner steel pipe assemblies stacked coaxially from top to bottom.

[0011] Each inner steel tube assembly includes an inner steel tube segment and at least one ring of connecting steel bars.

[0012] Each ring of connecting bars includes several connecting bars evenly distributed along the outer periphery of the inner steel pipe segment. Each connecting bar is radially distributed along the inner steel pipe segment. The inner end of each connecting bar is connected to the inner steel pipe segment. Each connecting bar has at least one longitudinal bar sleeve hole, and one longitudinal bar is inserted longitudinally into each longitudinal bar sleeve hole.

[0013] The core concrete column is poured between the inner steel tube and the TRC shell.

[0014] The TRC shell includes at least one loop of conductive carbon fiber woven mesh.

[0015] The negative terminal of the external power supply is connected to the longitudinal steel bar; the positive terminal of the external power supply is connected to each ring of carbon fiber woven mesh.

[0016] Each connecting rebar is figure-eight shaped and has two longitudinal rebar sleeve holes.

[0017] The inner end of each connecting rebar is connected to the inner steel pipe segment via threads.

[0018] Each inner steel pipe assembly includes two rings of connecting reinforcement bars: a top ring and a bottom ring.

[0019] The top ring connecting bars are set on the top outer periphery of the corresponding inner steel pipe segment, and have N connecting bars.

[0020] The bottom ring connecting bars are set at the bottom outer periphery of the corresponding inner steel pipe segment, and have N connecting bars.

[0021] The N connecting bars in the top ring and the N connecting bars in the bottom ring are arranged in a staggered manner in the circumferential direction.

[0022] N=3; the three connecting bars in the top ring are arranged in an equilateral triangle; the three connecting bars in the bottom ring are arranged in an inverted triangle.

[0023] The inner steel tube and the TRC outer shell provide composite confinement to the core reinforced concrete layer, increasing its compressive strength. Let F be the total axial compressive force that the CTRC-steel tube semi-assembled RC column can withstand. T Then F T The calculation formula is expressed as follows:

[0024] F T =F c +F e

[0025] in:

[0026] F c =f c A c +f y A s

[0027] F e =(σ r +σ sv A c

[0028]

[0029]

[0030] In the formula, F c The axial compressive bearing capacity provided for the core reinforced concrete layer.

[0031] F e Additional axial compressive bearing capacity provided for the inner steel tube, TRC shell, and connecting reinforcement to confine the core reinforced concrete layer.

[0032] f c The axial compressive strength of the core reinforced concrete layer.

[0033] A c The effective cross-sectional area of ​​the core concrete column.

[0034] f y This represents the yield strength of the longitudinal reinforcement.

[0035] A s This represents the total cross-sectional area of ​​the longitudinal reinforcement bars.

[0036] σ r The radial compressive stress is exerted on the core concrete column by the inner steel tube and TRC outer shell.

[0037] σ sv The radial compressive stress is applied to the core concrete column to be constrained by the connecting steel reinforcement.

[0038] n represents the number of layers or turns of carbon fiber woven mesh laid in the TRC shell.

[0039] f f This represents the ultimate tensile strength of the fibers in the carbon fiber woven mesh.

[0040] A f This refers to the cross-sectional area of ​​a single bundle of weft fibers in a carbon fiber woven mesh.

[0041] f a The yield strength of the inner steel pipe.

[0042] s1 is the mesh spacing of the carbon fiber woven mesh.

[0043] d a The thickness is the wall thickness of the inner steel pipe.

[0044] d1 is the distance between the inner steel pipe and the TRC outer shell.

[0045] 'a' represents the number of connecting steel rings arranged around the outer perimeter of an inner steel pipe segment.

[0046] N represents the number of connecting bars contained in one ring of connecting bars.

[0047] f yv This represents the yield strength of the connecting steel reinforcement.

[0048] A yv This represents the cross-sectional area of ​​the connecting reinforcing bars.

[0049] d2 is the inner diameter of the TRC shell.

[0050] s2 is the vertical height of an inner steel pipe segment.

[0051] The external power source is a solar-powered external power supply facility.

[0052] A method for fabricating a CTRC (steel tube semi-assembled RC) column for marine environments includes the following steps:

[0053] Step 1: Prefabricate inner steel pipe assembly: Prepare several inner steel pipe segments; arrange a rings of connecting steel bars on the outer periphery of each inner steel pipe segment; each ring of connecting steel bars includes N connecting steel bars evenly arranged along the circumference; each connecting steel bar has b longitudinal steel bar sleeve holes; where a≥1; N≥2; b≥1.

[0054] When a≥2, the connecting steel bars of two adjacent rings are staggered in the circumferential direction.

[0055] On the same cross section, a×N×b longitudinal steel bar sleeve holes will be formed.

[0056] Step 2, Prefabricate the TRC shell: Prepare a TRC shell consisting of n layers of carbon fiber woven mesh, each layer of carbon fiber woven mesh having an external conductor.

[0057] Step 3: Locate the longitudinal reinforcement bars: Arrange the a×N×b longitudinal reinforcement bars evenly in N circles along the circumference, and make them correspond one-to-one with the positions of the a×N×b longitudinal reinforcement bar sleeve holes.

[0058] Step 4: Assemble the inner steel pipe, which includes the following steps:

[0059] Step 4-1, hoisting: Hoist the prefabricated inner steel pipe assembly from Step 1 directly above the positioned longitudinal reinforcing bars, ensuring that the a×N×b longitudinal reinforcing bar sleeve holes of the inner steel pipe assembly are all directly above the corresponding longitudinal reinforcing bars.

[0060] Step 4-2, Installing longitudinal reinforcement: The height of the inner steel pipe assembly decreases, so that the a×N×b longitudinal reinforcement sleeve holes of the inner steel pipe assembly are all fitted onto the outer periphery of the corresponding longitudinal reinforcement; the height of the inner steel pipe assembly continues to decrease to the bottom.

[0061] Step 4-3, Assembly: Repeat steps 4-1 to 4-2 until all the inner steel pipe assemblies are assembled. At this point, all the inner steel pipe assemblies are stacked vertically to form the assembled inner steel pipe. The inner steel pipe and the longitudinal reinforcing bars together form a steel skeleton.

[0062] Step 5: Install the TRC shell: Hoist the prefabricated TRC shell from Step 2 directly above the inner steel pipe assembled in Step 4. Then, lower the TRC shell to the bottom and coaxially fit it around the outermost longitudinal steel bar.

[0063] Step 6, Pouring: Pour core concrete between the inner steel pipe and the TRC outer shell and cure it to form a double-walled confined column.

[0064] Step 7, Powering On: Connect the negative terminal of the external power supply to the longitudinal reinforcing bar, and connect the positive terminal to the external conductors of the n-layer carbon fiber woven mesh to form an impressed current cathodic protection circuit (ICCP). The n-layer carbon fiber woven mesh serves as the auxiliary anode of the ICCP. The external power supply continuously supplies electrons to the inner steel pipe through the longitudinal and connecting reinforcing bars. This inhibits the loss of electrons from the steel skeleton, thereby preventing corrosion by seawater. Furthermore, chloride ions in the seawater migrate towards the auxiliary anode, where a chloride evolution reaction occurs, reducing the chloride ion content that penetrates the core reinforced concrete layer and the steel skeleton.

[0065] In step 1, a = 2; N = 3; b = 2; 12 longitudinal steel bar sleeve holes will be formed on the same cross section.

[0066] Step 2, the method for preparing the TRC shell, includes the following steps:

[0067] Step 2-1: Laying plastic film: Select a PVC pipe of the specified size and lay a layer of plastic film on the PVC pipe. Apply interface adhesive evenly to the plastic film.

[0068] Step 2-2: Preparation of carbon fiber woven mesh: Apply conductive silver paste to the wire connection points of the carbon fiber woven mesh, then clamp and adhere it with copper foil, and finally solder the wires onto the copper foil using a soldering method, thereby producing a carbon fiber woven mesh with wires.

[0069] Steps 2-3: Apply fine aggregate concrete: Apply a layer of fine aggregate concrete onto the plastic film to form the first layer of fine aggregate concrete.

[0070] Step 2-4: Laying carbon fiber woven mesh: Lay a layer of carbon fiber woven mesh prepared in step 2-2 on the outside of the first layer of fine aggregate concrete.

[0071] Steps 2-5: Repeat steps 2-3 to 2-4 to complete the laying of the set n layers of carbon fiber woven mesh until the designed thickness is reached and cured.

[0072] Steps 2-6: Forming the TRC casing: After curing is complete, remove the internal PVC pipe and plastic film to form the TRC casing.

[0073] The present invention has the following beneficial effects:

[0074] 1. Cost savings: Compared with traditional concrete columns, this invention uses a hollow section, which can effectively reduce the amount of concrete poured and the self-weight of the structure while ensuring structural performance, thus saving economic costs. It can be applied to concrete columns with larger cross-section requirements.

[0075] 2. Improved Mechanical Properties: This invention improves the load-bearing capacity of the core concrete by using an inner steel pipe wall and a TRC outer shell to confine the concrete. Furthermore, the invention employs double rows of circumferential longitudinal reinforcement, which directly provides axial load-bearing capacity, effectively improving the compressive performance of the double-walled confined column.

[0076] 3. Excellent Corrosion Resistance: This invention utilizes a double-walled restraint column with a TRC shell, exhibiting superior durability in marine environments. The TRC shell, acting as a protective layer for the double-walled restraint column, effectively prevents the steel frame from being directly exposed to the marine environment, thus providing passive protection. Furthermore, the carbon fiber woven mesh within the TRC is a conductive material, and the shell is evenly distributed around the double-walled restraint column. Therefore, an external current cathodic protection method can be employed, allowing the TRC shell to act as an auxiliary anode, suppressing the electron loss process of the internal steel frame and providing active protection. The combined effect of these two protective measures significantly enhances the overall structural durability.

[0077] 4. Shortened Construction Cycle: Marine environments place high demands on construction, typically requiring rapid installation. This invention employs a semi-prefabricated process. During construction, simply aligning the holes of the connecting bars in the inner steel pipe assembly with the longitudinal reinforcing bars and hoisting them together allows for rapid assembly to form the inner steel pipe wall of the structure. Positioning is simple and convenient, avoiding the difficulties of on-site welding of reinforcing bars in traditional double-walled confined columns. Furthermore, the inner steel pipe and the TRC outer shell can serve as the inner support plate and permanent outer formwork, respectively, for pouring the core concrete, eliminating the need for additional formwork and simplifying on-site construction, making on-site construction faster and more efficient. Attached Figure Description

[0078] Figure 1 The diagram shows a structural schematic of a CTRC-steel tube semi-assembled RC column for marine environments according to the present invention.

[0079] Figure 2 A three-dimensional schematic diagram of the inner steel pipe assembly of the present invention is shown.

[0080] Figure 3 The diagram shows the combined connection of the inner steel pipe assembly and the longitudinal reinforcing bars of the present invention.

[0081] Figure 4 The diagram shows a cross-sectional view of the inner steel pipe assembly and longitudinal reinforcing bars of the present invention at the connecting reinforcing bars.

[0082] Figure 5 The schematic diagram of the impressed current cathodic protection method of the present invention is shown.

[0083] Figure 6 The diagram shows the force analysis of the constraint effect of the outer shell and inner steel pipe of the TRC on the core concrete.

[0084] Figure 7 The diagram shows the stress analysis of the constraint effect of the reinforcing steel bars on the core concrete of the present invention.

[0085] Among them are:

[0086] 1. Inner steel pipe assembly; 11. Inner steel pipe segment; 12. Connecting reinforcement; 13. Connecting hole;

[0087] 2. Core reinforced concrete layer; 21. Longitudinal reinforcement;

[0088] 3. TRC outer shell; 31. Carbon fiber woven mesh;

[0089] 4. External power supply. Detailed Implementation

[0090] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0091] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0092] like Figure 1 As shown, a CTRC-steel pipe semi-assembled RC column for marine environments includes an inner steel pipe, a TRC outer shell 3, a core reinforced concrete layer 2, and an external power supply 4.

[0093] The core reinforced concrete layer includes the core concrete column and the longitudinal steel bars 21 embedded in the core concrete column.

[0094] like Figure 2 , Figure 3 and Figure 4 As shown, the inner steel pipe includes several inner steel pipe assemblies 1 stacked coaxially from top to bottom. Each inner steel pipe assembly 1 includes an inner steel pipe segment 11 and at least one ring of connecting steel bars 12.

[0095] Each ring of connecting bars includes several connecting bars evenly distributed along the outer periphery of the inner steel pipe segment. Each connecting bar is arranged radially along the inner steel pipe segment. The inner end of each connecting bar is connected to the inner steel pipe segment. Each connecting bar has at least one longitudinal bar sleeve hole, and a longitudinal bar is inserted longitudinally into each longitudinal bar sleeve hole.

[0096] In this embodiment, two rings of connecting steel bars are preferred, namely the top ring connecting steel bars and the bottom ring connecting steel bars.

[0097] The top ring connecting bars are set on the top outer periphery of the corresponding inner steel pipe segment, and have N connecting bars.

[0098] The bottom ring connecting bars are set at the bottom outer periphery of the corresponding inner steel pipe segment, and have N connecting bars.

[0099] The N connecting bars in the top ring and the N connecting bars in the bottom ring are staggered in the circumferential direction.

[0100] Furthermore, in this embodiment, N=3 is preferred; the three connecting bars in the top ring connecting bars are arranged in an equilateral triangle; and the three connecting bars in the bottom ring connecting bars are arranged in an inverted triangle.

[0101] Furthermore, each connecting steel bar is preferably shaped like an 8 and has two longitudinal steel bar sleeve holes.

[0102] A connection hole 13 is reserved at the installation location of the connecting steel bar in each inner steel pipe segment, and the inner end (preferably a threaded rod) of each connecting steel bar is connected to the connection hole of the inner steel pipe segment by thread.

[0103] The core concrete column is poured between the inner steel tube and the TRC shell.

[0104] The TRC shell comprises at least one ring of conductive carbon fiber woven mesh 31 and fine aggregate concrete. The carbon fiber woven mesh serves as reinforcement, and the fine aggregate concrete serves as the matrix.

[0105] like Figure 5 As shown, the negative terminal of the external power supply 4 is energized and connected to the longitudinal reinforcing bars; the positive terminal of the external power supply is energized and connected to each ring of carbon fiber woven mesh. The longitudinal reinforcing bars are connected to the internal steel frame through connecting reinforcing bars, thereby establishing an electronic transmission path between the TRC outer shell and the internal steel frame.

[0106] In this embodiment, the external power source is preferably a solar-powered external power supply facility, which uses a solar DC power source.

[0107] like Figure 6 and Figure 7 As shown, the inner steel tube and the TRC outer shell provide composite restraint for the core reinforced concrete layer, increasing its compressive strength. Let F be the total axial pressure that the CTRC-steel tube semi-assembled RC column can withstand. T Then F T The calculation formula is expressed as follows:

[0108] F T =F c +F e

[0109] in:

[0110] F c =f c A c +f y A s

[0111] F e =(σ r +σ sv A c

[0112]

[0113]

[0114] In the formula, F c The axial compressive bearing capacity provided for the core reinforced concrete layer.

[0115] F e Additional axial compressive bearing capacity provided for the inner steel tube, TRC shell, and connecting reinforcement to confine the core reinforced concrete layer.

[0116] f c The axial compressive strength of the core reinforced concrete layer.

[0117] A c The effective cross-sectional area of ​​the core concrete column.

[0118] f y This represents the yield strength of the longitudinal reinforcement.

[0119] A s This represents the total cross-sectional area of ​​the longitudinal reinforcement bars.

[0120] σ r The radial compressive stress is exerted on the core concrete column by the inner steel tube and TRC outer shell.

[0121] σ sv The radial compressive stress is applied to the core concrete column to be constrained by the connecting steel reinforcement.

[0122] n represents the number of layers or turns of carbon fiber woven mesh laid in the TRC shell.

[0123] f f This represents the ultimate tensile strength of the fibers in the carbon fiber woven mesh.

[0124] A f This refers to the cross-sectional area of ​​a single bundle of weft fibers in a carbon fiber woven mesh.

[0125] f a The yield strength of the inner steel pipe.

[0126] s1 is the mesh spacing of the carbon fiber woven mesh.

[0127] d a The thickness is the wall thickness of the inner steel pipe.

[0128] d1 is the distance between the inner steel pipe and the TRC outer shell.

[0129] 'a' represents the number of connecting steel rings arranged around the outer perimeter of an inner steel pipe segment.

[0130] N represents the number of connecting bars contained in one ring of connecting bars.

[0131] f yv This represents the yield strength of the connecting steel reinforcement.

[0132] A yv This represents the cross-sectional area of ​​the connecting reinforcing bars.

[0133] d2 is the inner diameter of the TRC shell.

[0134] s2 is the vertical height of an inner steel pipe segment.

[0135] A method for preparing a CTRC-steel tube semi-assembled RC column for marine environments includes the following steps.

[0136] Step 1: Prefabricate inner steel pipe assembly: Prepare several inner steel pipe segments; arrange a rings of connecting steel bars on the outer periphery of each inner steel pipe segment; each ring of connecting steel bars includes N connecting steel bars evenly arranged along the circumference; each connecting steel bar has b longitudinal steel bar sleeve holes; where a≥1; N≥2; b≥1.

[0137] When a≥2, the connecting steel bars of two adjacent rings are staggered in the circumferential direction.

[0138] On the same cross-section, a×N×b longitudinal reinforcing bar holes will be formed. Based on this staggered arrangement, the inner steel pipe assembly will have 6 connecting reinforcing bars at the joint section.

[0139] In this embodiment, a=2; N=3; b=2; and 12 longitudinal steel bar sleeve holes will be formed on the same cross section.

[0140] Step 2, Prefabricate the TRC shell: Prepare a TRC shell consisting of n layers of carbon fiber woven mesh, each layer of carbon fiber woven mesh having an external conductor.

[0141] The method for preparing the above-mentioned TRC shell preferably includes the following steps.

[0142] Step 2-1: Laying plastic film: Select a PVC pipe of the specified size and lay a layer of plastic film on the PVC pipe. Apply interface adhesive evenly to the plastic film.

[0143] Step 2-2: Preparation of carbon fiber woven mesh: Apply conductive silver paste to the wire connection points of the carbon fiber woven mesh, then clamp and adhere it with copper foil, and finally solder the wires onto the copper foil using a soldering method, thereby producing a carbon fiber woven mesh with wires.

[0144] Steps 2-3: Apply fine aggregate concrete: Apply a layer of fine aggregate concrete onto the plastic film to form the first layer of fine aggregate concrete.

[0145] Step 2-4: Laying carbon fiber woven mesh: Lay a layer of carbon fiber woven mesh prepared in step 2-2 on the outside of the first layer of fine aggregate concrete.

[0146] Steps 2-5: Repeat steps 2-3 to 2-4 to complete the laying of the set n layers of carbon fiber woven mesh until the designed thickness is reached and cured.

[0147] Steps 2-6: Forming the TRC casing: After curing is complete, remove the internal PVC pipe and plastic film to form the TRC casing.

[0148] Step 3, Positioning the longitudinal reinforcement: It is preferable to use positioning clamps (such as column reinforcement spacing frames) to evenly arrange a×N×b longitudinal reinforcements in N circles along the circumference, and to correspond one-to-one with the position of the a×N×b longitudinal reinforcement sleeve holes.

[0149] Step 4: Assemble the inner steel pipe, which includes the following steps:

[0150] Step 4-1, hoisting: Hoist the prefabricated inner steel pipe assembly from Step 1 directly above the positioned longitudinal reinforcing bars, ensuring that the a×N×b longitudinal reinforcing bar sleeve holes of the inner steel pipe assembly are all directly above the corresponding longitudinal reinforcing bars.

[0151] Step 4-2, Installing longitudinal reinforcement: The height of the inner steel pipe assembly decreases, so that the a×N×b longitudinal reinforcement sleeve holes of the inner steel pipe assembly are all fitted onto the outer periphery of the corresponding longitudinal reinforcement; the height of the inner steel pipe assembly continues to decrease to the bottom.

[0152] Step 4-3, Assembly: Repeat steps 4-1 to 4-2 until all the inner steel pipe assemblies are assembled. At this point, all the inner steel pipe assemblies are stacked vertically to form the assembled inner steel pipe. The inner steel pipe and the longitudinal reinforcing bars together form a steel skeleton.

[0153] Step 5: Install the TRC shell: Hoist the prefabricated TRC shell from Step 2 directly above the inner steel pipe assembled in Step 4. Then, lower the TRC shell to the bottom and coaxially fit it around the outermost longitudinal steel bar.

[0154] Step 6, Pouring: Pour core concrete between the inner steel pipe and the TRC outer shell and cure it to form a double-walled confined column.

[0155] Step 7, Powering On: Connect the negative terminal of the external power supply to the longitudinal reinforcing bar, and connect the positive terminal to the external conductors of the n-layer carbon fiber woven mesh to form an impressed current cathodic protection circuit (ICCP). The n-layer carbon fiber woven mesh serves as the auxiliary anode of the ICCP. The external power supply continuously supplies electrons to the inner steel pipe through the longitudinal and connecting reinforcing bars. This inhibits the loss of electrons from the steel skeleton, thereby preventing corrosion by seawater. Furthermore, chloride ions in the seawater migrate towards the auxiliary anode, where a chloride evolution reaction occurs, reducing the chloride ion content that penetrates the core reinforced concrete layer and the steel skeleton.

[0156] The reaction equations for the anode and cathode are as follows:

[0157] 2Cl - -2e- →Cl2 (anode)

[0158] Fe 2+ +2e - →Fe (cathode)

[0159] This invention, by employing an inner steel pipe and a TRC outer shell, effectively restrains the core concrete while considering economic efficiency, thereby improving the axial compressive bearing capacity of the RC column. This semi-prefabricated RC column eliminates the need for additional formwork during core concrete pouring; the inner steel pipe serves as an internal support plate, and the TRC outer shell acts as a permanent external formwork, effectively simplifying the construction process and saving formwork materials. Furthermore, by utilizing the excellent conductivity of the carbon fiber woven mesh within the TRC outer shell, this invention employs impressed current cathodic protection, using the carbon fiber woven mesh bundle as the anode and the internal steel skeleton as the cathode, thus protecting the internal steel skeleton and effectively improving the overall structural durability. This patented invention improves the mechanical properties, bending stiffness, compressive strength, seismic performance, and corrosion resistance of hollow tube columns; it is convenient to construct, shortens the construction period, and offers good economic benefits; it is particularly suitable for construction and bridge projects in harsh environments prone to corrosion, such as marine, humid, saline, and alkaline soils.

[0160] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a CTRC-steel tube semi-assembled RC column for marine environments, characterized in that: Includes the following steps: Step 1: Prefabricate inner steel pipe assembly: Prepare several inner steel pipe segments; arrange a rings of connecting steel bars on the outer periphery of each inner steel pipe segment; each ring of connecting steel bars includes N connecting steel bars evenly arranged along the circumference; each connecting steel bar has b longitudinal steel bar sleeve holes; where a≥1; N≥2; b≥1; When a≥2, the connecting steel bars of two adjacent rings are staggered in the circumferential direction. On the same cross section, a×N×b longitudinal steel bar sleeve holes will be formed; Step 2, Prefabrication of TRC Shell: Preparation including The TRC shell is made of multiple layers of carbon fiber woven mesh, each layer of which has an external conductor. Step 3: Locate the longitudinal reinforcement bars: Arrange the a×N×b longitudinal reinforcement bars evenly in N circles along the circumference, and make them correspond one-to-one with the positions of the a×N×b longitudinal reinforcement bar sleeve holes; Step 4: Assemble the inner steel pipe, which includes the following steps: Step 4-1, hoisting: Hoist the prefabricated inner steel pipe assembly from Step 1 directly above the positioned longitudinal reinforcing bars, and ensure that the a×N×b longitudinal reinforcing bar sleeve holes of the inner steel pipe assembly are all directly above the corresponding longitudinal reinforcing bars. Step 4-2, Installing longitudinal reinforcement: The height of the inner steel pipe assembly decreases, so that the a×N×b longitudinal reinforcement sleeve holes of the inner steel pipe assembly are all fitted onto the outer periphery of the corresponding longitudinal reinforcement; the height of the inner steel pipe assembly continues to decrease to the bottom. Step 4-3, Assembly: Repeat steps 4-1 to 4-2 until all the inner steel pipe assemblies are assembled; at this point, all the inner steel pipe assemblies are stacked vertically to form the assembled inner steel pipe; the inner steel pipe and the longitudinal reinforcing bars together form a steel skeleton; Step 5: Install the TRC shell: Hoist the prefabricated TRC shell from Step 2 directly above the inner steel pipe assembled in Step 4. Then, lower the TRC shell to the bottom and coaxially fit it around the outermost longitudinal steel bar. Step 6, Pouring: Pour core concrete between the inner steel pipe and the TRC outer shell and cure it to form a double-walled confined column; Step 7, Power On: Connect the negative terminal of the external power supply to the longitudinal steel bar, and the positive terminal to... The external conductors of the multi-layered carbon fiber woven mesh are all electrically connected, forming an impressed current cathodic protection circuit (ICCP); among them... The carbon fiber woven mesh serves as the auxiliary anode of the impressed current cathodic protection circuit ICCP. The external power supply continuously delivers electrons to the inner steel pipe through the longitudinal steel bars and connecting steel bars. On the one hand, it can inhibit the loss of electrons in the steel skeleton, thereby inhibiting the corrosion of the steel skeleton by seawater. On the other hand, chloride ions in the seawater will migrate to the auxiliary anode and undergo a chloride evolution reaction at the auxiliary anode, reducing the chloride ion content that invades the core reinforced concrete layer and the steel skeleton.

2. The method for preparing a CTRC-steel pipe semi-assembled RC column for marine environments according to claim 1, characterized in that: In step 1, a=2; N=3; b=2; 12 longitudinal steel bar sleeve holes will be formed on the same cross section.

3. The method for preparing a CTRC-steel pipe semi-assembled RC column for marine environments according to claim 1, characterized in that: Step 2, the method for preparing the TRC shell, includes the following steps: Step 2-1: Laying plastic film: Select a PVC pipe of the specified size and lay a layer of plastic film on the PVC pipe. Apply interface adhesive evenly to the plastic film. Step 2-2: Preparation of carbon fiber woven mesh: Apply conductive silver paste to the wire connection points of the carbon fiber woven mesh, then clamp and stick it with copper foil, and finally solder the wires onto the copper foil using a soldering method, thereby producing a carbon fiber woven mesh with wires. Steps 2-3: Apply fine aggregate concrete: Apply a layer of fine aggregate concrete onto the plastic film to form the first layer of fine aggregate concrete; Step 2-4: Laying carbon fiber woven mesh: Lay a layer of carbon fiber woven mesh prepared in step 2-2 on the outside of the first layer of fine aggregate concrete. Steps 2-5: Repeat steps 2-3 to 2-4 to complete the setup. Laying layers of carbon fiber woven mesh until the designed thickness is achieved and then curing; Steps 2-6: Forming the TRC casing: After curing is complete, remove the internal PVC pipe and plastic film to form the TRC casing.

4. A CTRC-steel tube semi-assembled RC column for marine environments, based on the preparation method of the CTRC-steel tube semi-assembled RC column for marine environments according to any one of claims 1-3, characterized in that: Includes inner steel pipe, TRC outer shell, core reinforced concrete layer and external power supply; The core reinforced concrete layer includes the core concrete column and the longitudinal reinforcement embedded in the core concrete column. The inner steel pipe consists of several inner steel pipe assemblies that are coaxially stacked from top to bottom; Each inner steel tube assembly includes an inner steel tube segment and at least one ring of connecting steel bars; Each ring of connecting bars includes several connecting bars evenly distributed along the outer periphery of the inner steel pipe segment. Each connecting bar is radially distributed along the inner steel pipe segment. The inner end of each connecting bar is connected to the inner steel pipe segment. Each connecting bar has at least one longitudinal bar sleeve hole, and one longitudinal bar is inserted longitudinally into each longitudinal bar sleeve hole. The core concrete column is poured between the inner steel pipe and the TRC outer shell; The TRC shell includes at least one loop of conductive carbon fiber woven mesh; The negative terminal of the external power supply is connected to the longitudinal steel bars; the positive terminal of the external power supply is connected to each ring of carbon fiber woven mesh.

5. The CTRC-steel pipe semi-assembled RC column for marine environments according to claim 4, characterized in that: Each connecting rebar is figure-eight shaped and has two longitudinal rebar sleeve holes.

6. The CTRC-steel tube semi-assembled RC column for marine environments according to claim 4 or 5, characterized in that: The inner end of each connecting rebar is connected to the inner steel pipe segment via threads.

7. The CTRC-steel tube semi-assembled RC column for marine environments according to claim 4 or 5, characterized in that: Each inner steel pipe assembly includes two rings of connecting reinforcement bars, namely the top ring of connecting reinforcement bars and the bottom ring of connecting reinforcement bars; The top ring connecting bars are set on the top outer periphery of the corresponding inner steel pipe segment, and have N connecting bars; The bottom ring connecting bars are set at the bottom outer periphery of the corresponding inner steel pipe segment, and have N connecting bars; The N connecting bars in the top ring and the N connecting bars in the bottom ring are arranged in a staggered manner in the circumferential direction.

8. The CTRC-steel tube semi-assembled RC column for marine environments according to claim 7, characterized in that: N = 3; the three connecting bars in the top ring are arranged in an equilateral triangle; the three connecting bars in the bottom ring are arranged in an inverted triangle.

9. The CTRC-steel tube semi-assembled RC column for marine environments according to claim 4, characterized in that: The inner steel tube and TRC outer shell provide composite restraint for the core reinforced concrete layer, increasing its compressive strength. The total axial pressure that the CTRC-steel tube semi-assembled RC column can withstand is... ,but The calculation formula is expressed as follows: ； in: ； ； ； ； In the formula, The axial compressive bearing capacity provided for the core reinforced concrete layer; Additional axial compressive bearing capacity provided for the inner steel tube, TRC shell and connecting reinforcement to confine the core reinforced concrete layer; The axial compressive strength of the core reinforced concrete layer; The effective cross-sectional area of ​​the core concrete column; The yield strength of the longitudinal reinforcement; This represents the total cross-sectional area of ​​the longitudinal reinforcement bars; The radial compressive stress is exerted on the core concrete column by the inner steel tube and TRC outer shell. To constrain the radial compressive stress on the core concrete column by connecting steel reinforcement; The number of layers or turns of carbon fiber woven mesh to be laid in the TRC shell; This represents the ultimate tensile strength of the fibers in the carbon fiber woven mesh. This refers to the cross-sectional area of ​​a single bundle of weft fibers in a carbon fiber woven mesh. The yield strength of the inner steel pipe; The mesh spacing of the carbon fiber woven mesh; The thickness is the wall thickness of the inner steel pipe; This is the distance between the inner steel pipe and the TRC outer shell; The number of connecting steel rings arranged around the outer perimeter of an inner steel pipe segment; This refers to the number of connecting bars included in one ring of connecting bars; The yield strength of the connecting steel bars; This represents the cross-sectional area of ​​the connecting reinforcing bars; This refers to the inner diameter of the TRC casing; This refers to the vertical height of an inner steel pipe segment.

10. The CTRC-steel tube semi-assembled RC column for marine environments according to claim 4, characterized in that: The external power source is a solar-powered external power supply facility.

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