Intelligent composite bar and concrete component operation and maintenance method using the same

Abstract

The application discloses an intelligent composite reinforcing bar and a concrete component operation and maintenance method applying the intelligent composite reinforcing bar, relates to the concrete component operation and maintenance field, and the intelligent composite reinforcing bar comprises the following steps: a groove with a specific depth is formed on an inner core reinforcing bar; an optical fiber wrapped with a polyethylene protective sleeve is embedded in the groove; the outer side of the inner core reinforcing bar after embedding the optical fiber is wrapped with a GFRP layer with a first set thickness; and the outer side of the GFRP layer is wrapped with a CFRP layer with a second set thickness. The concrete component operation and maintenance method applying the intelligent composite reinforcing bar comprises the following steps: the target bearing capacity, the target ductility coefficient, the initial structure parameter and the cross section area ratio of the concrete component are determined; the total cross section area of the basic reinforcing bar, the optimal cross section area ratio, the optimal structure parameter and the optimal current density are obtained by continuous correction, and the concrete component is constructed by using the total cross section area of the basic reinforcing bar, the optimal cross section area ratio, the optimal structure parameter and the optimal current density and the cathodic protection is implemented. The intelligent composite reinforcing bar is obtained by improving the ordinary reinforcing bar structure, and the effective operation and maintenance of the concrete component is completed by applying the intelligent composite reinforcing bar.

Description

Technical Field

[0001] The present application relates to the technical field of operation and maintenance of concrete components, and in particular to an intelligent composite reinforcement and a method for operation and maintenance of concrete components using the intelligent composite reinforcement. Background Art

[0002] Rebar and concrete, due to their low cost, widespread availability, and durability, are the most widely used and in-demand building materials in civil engineering infrastructure construction. In civil engineering, buildings are typically constructed using concrete components cast with rebar and concrete. Therefore, the strength and lifespan of concrete components significantly impact the quality of the building.

[0003] At present, due to the long-term service of buildings in coastal areas in high temperature, high humidity and high chloride ion environment, the steel bars inside the concrete components are prone to corrosion and the concrete outside is also prone to cracking. The corrosion of steel bars and the cracking of concrete seriously affect the service performance of concrete components and may even cause the collapse and damage of the entire building.

[0004] To address and solve the above problems, existing technologies mainly use the following methods to maintain concrete components: 1) Use fiber-reinforced composite bars to replace ordinary steel bars to increase the overall strength of the concrete component; 2) Apply sacrificial anode cathodic protection to the concrete component, using carbon fiber reinforced composite materials (CFRP) as the anode material in cathodic protection to protect the steel bars in the concrete component from corrosion through the sacrifice of the anode material; 3) Add rust inhibitors to the concrete to improve the concrete's impermeability and thus ensure the overall strength of the concrete component. However, the above methods can only improve the condition of the concrete component from a unilateral perspective and have little effect on the actual maintenance of the concrete component. Summary of the Invention

[0005] The purpose of this application is to provide an intelligent composite reinforcement and a concrete component operation and maintenance method using the intelligent composite reinforcement, by improving the ordinary steel bar structure to obtain the intelligent composite reinforcement, and using the intelligent composite reinforcement to complete the effective operation and maintenance of the concrete component.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a smart composite reinforcement, the smart composite reinforcement comprising at least an inner core steel bar, a GFRP layer, and a CFRP layer arranged sequentially from the inside to the outside;

[0008] The inner core steel bar is provided with a groove of a specific depth; an optical fiber covered with a polyethylene protective sheath is embedded in the groove; the outer side of the inner core steel bar after embedding the optical fiber is wrapped with a GFRP layer of a first set thickness; the outer side of the GFRP layer is wrapped with a CFRP layer of a second set thickness;

[0009] The inner core steel bar is used to provide mechanical support for the smart composite bar; the optical fiber is used to cooperate with the demodulator to complete the strain sensing of the smart composite bar; the GFRP layer is used to protect the inner core steel bar from current corrosion; and the CFRP layer is used to serve as the anode material for cathodic protection.

[0010] In a second aspect, the present application further provides a method for operating and maintaining a concrete component using the intelligent composite reinforcement described in the first aspect. The method for operating and maintaining a concrete component using the intelligent composite reinforcement includes:

[0011] Determining a target bearing capacity, target ductility coefficient, initial structural parameters, and cross-sectional area ratio of a concrete component; the concrete component is composed of at least smart composite reinforcement, bottom stress reinforcement, and concrete; the cross-sectional area ratio is the ratio of the cross-sectional area of ​​the CFRP layer to the total cross-sectional area of ​​the reinforcement; the total cross-sectional area of ​​the reinforcement is the sum of the cross-sectional areas of the inner core reinforcement and the bottom stress reinforcement;

[0012] Based on the initial structural parameters of the concrete component, determine the initial total cross-sectional area of ​​the steel bars;

[0013] Calculating the actual bearing capacity and ductility coefficient of the concrete member based on the initial structural parameters, cross-sectional area ratio, and total cross-sectional area of ​​the steel bars of the concrete member, and correcting the initial total cross-sectional area, cross-sectional area ratio, and structural parameters of the steel bars according to the target bearing capacity and the target ductility coefficient to obtain the basic total cross-sectional area of ​​the steel bars, the basic cross-sectional area ratio, and the basic structural parameters;

[0014] Determine the initial current density based on the target service life of the concrete component;

[0015] Based on the initial current density, calculating the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection, and correcting the initial current density according to the target bearing capacity and the target ductility coefficient to obtain a basic current density;

[0016] determining a corrosion growth rate of bottom reinforcement bars in a concrete member, and when the corrosion growth rate of the bottom reinforcement bars is not within a set speed range, modifying the basic current density to obtain an optimal current density;

[0017] Based on the optimal current density, calculating the bearing capacity and ductility coefficient of the concrete component when it reaches a target service life under cathodic protection, and correcting the foundation cross-sectional area ratio and the foundation structural parameters according to the target bearing capacity and the target ductility coefficient to obtain an optimal cross-sectional area ratio and optimal structural parameters;

[0018] A concrete component is constructed based on the total cross-sectional area of ​​the basic steel bars, the optimal cross-sectional area ratio and the optimal structural parameters, and cathodic protection is performed on the concrete component using the optimal current density.

[0019] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0020] On the one hand, the smart composite bar of the present application adds a glass fiber reinforced plastic (GFRP) layer between the inner core steel bar and the CFRP layer. In addition to further increasing the strength of the smart composite bar, the GFRP layer can also protect the inner core steel bar from current corrosion. If the CFRP layer is in direct contact with the inner core steel bar, then with the activation of cathodic protection, the current in the CFRP layer will directly corrode the inner core steel bar, seriously affecting its normal life. On the other hand, in the operation and maintenance process of concrete components using smart composite bars, the present application fully considers the influence of factors such as the corrosion growth rate of the bottom stress reinforcement, and based on these factors, continuously modifies the initial structural parameters, cross-sectional area ratio, total cross-sectional area of ​​steel bars and current density of the concrete components. The concrete components are constructed by modifying the structural parameters, cross-sectional area ratio and total cross-sectional area of ​​steel bars to ensure the effectiveness of the cross-sectional area of ​​the inner core steel bar, CFRP layer and bottom stress reinforcement in the concrete components. At the same time, the modified current density is also used to effectively perform cathodic protection on the concrete components. Therefore, the present application achieves effective operation and maintenance from the perspective of the construction and cathodic protection of the concrete components. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A cross-sectional view of the intelligent composite reinforcement provided in an embodiment of the present application;

[0023] Figure 2 A cross-sectional view of an inner core steel bar after grooves are formed according to an embodiment of the present application;

[0024] Figure 3A schematic diagram of the structure of the intelligent composite reinforcement provided in an embodiment of the present application;

[0025] Figure 4 A flowchart of a method for operating and maintaining a concrete component using intelligent composite reinforcement provided in an embodiment of the present application;

[0026] Figure 5 The curve showing the change in corrosion growth rate and time of the bottom stress reinforcement provided in the embodiment of the present application.

[0027] Explanation of symbols:

[0028] Inner core steel bar-1, GFRP layer-2, CFRP layer-3, optical fiber-4. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] The purpose of this application is to provide an intelligent composite reinforcement and a concrete component operation and maintenance method using the intelligent composite reinforcement, by improving the ordinary steel bar structure to obtain the intelligent composite reinforcement, and using the intelligent composite reinforcement to complete the effective operation and maintenance of the concrete component.

[0031] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment provides an intelligent composite reinforcement, which includes at least an inner core steel bar 1, a GFRP layer 2 and a CFRP layer 3 arranged in sequence from the inside to the outside; a groove of a specific depth is opened on the inner core steel bar 1; an optical fiber 4 wrapped with a polyethylene protective sheath is buried in the groove; after the optical fiber 4 is buried, the outer side of the inner core steel bar 1 is wrapped with a GFRP layer 2 of a first set thickness; the outer side of the GFRP layer 2 is wrapped with a CFRP layer 3 of a second set thickness; the second set thickness is greater than the first set thickness.

[0034] Specifically, the inner core steel bar 1 is used to provide mechanical support for the smart composite bar; the optical fiber 4 is used to cooperate with the demodulator to complete the strain sensing of the smart composite bar; the GFRP layer 2 is used to protect the inner core steel bar 1 from current corrosion; and the CFRP layer 3 is used to act as the anode material for cathodic protection.

[0035] In this embodiment, the depth of the groove on the inner steel bar 1 and the thickness of the GFRP layer 2 are generally not directly related to the operation and maintenance of the concrete component. They can usually be set according to actual needs. Generally, the groove on the inner steel bar 1 is set to a 1.5mm×1.5mm square groove, and the thickness of the GFRP layer 2 is set to 0.2mm. Because the thickness of the CFRP layer 3 is directly related to the operation and maintenance of the concrete component, it cannot be set arbitrarily. It needs to be determined in combination with factors such as the target bearing capacity, target ductility coefficient, structural parameters, and cross-sectional area ratio of the concrete component. The specific determination process will be elaborated in detail in the operation and maintenance method of concrete components using intelligent composite bars.

[0036] Furthermore, this embodiment also provides a method for manufacturing an intelligent composite rib, which specifically includes:

[0037] The first step is to cut grooves: Use a metal notching machine to etch along the length of the inner steel bar 1. Figure 2 The 1.5mm×1.5mm square groove is shown.

[0038] The second step is decontamination: use sandpaper to remove the rust stains on the surface of the inner core steel bar 1 after the square groove is etched, and then use acetone to clean it.

[0039] The third step is to make a fiber optic protective cover: cut the polyethylene film material into strips of appropriate width, place the bare optical fiber in the center of the longitudinal wrapping machine, wrap the strip polyethylene film material around the outside of the optical fiber through the longitudinal wrapping machine, and form a tight protective cover by heating or bonding it. After it cools and solidifies, a fiber 4 covered with a polyethylene protective cover is formed.

[0040] The fourth step is to implant the optical fiber: place the optical fiber 4 covered with the polyethylene protective sheath at the bottom of the square groove of the inner core steel bar 1, keep it straight and fix it with transparent tape, then put glue in the square groove to fix it to the inner core steel bar 1 as a whole.

[0041] Step 5: Production of the GFRP layer: To ensure that the GFRP layer 2 fits tightly against the inner core steel bar 1, the fiber material needs to be cut into appropriate widths and lengths according to the size and shape of the inner core steel bar 1 so that it can be woven along the mold. The cut fiber material is woven along the surface of the inner core steel bar. Starting from one end of the inner core steel bar, the fiber material is evenly laid on the mold surface and woven in an interlaced manner according to the designed fiber direction and number of layers. Each layer of fiber material should form a certain angle (usually 45 degrees or 90 degrees) with the previous layer to ensure the overall strength and stability of the multi-layer fiber material. In addition, after each layer of fiber material is woven, it is compacted using a roller or scraper to ensure that the fiber material fits tightly against the surface of the inner core steel bar, expel air, and tightly bond the fiber materials between each layer. Since the GFRP layer mainly serves as an insulator, in order to ensure that current does not pass through the inner core steel bar, an insulating glue is selected and evenly applied to each layer of fiber material using a brush, roller, or spray gun to ensure that the resin completely penetrates each layer of fiber material to avoid the formation of bubbles and dry spots.

[0042] Step 6: CFRP layer production: The production method of CFRP layer 3 is basically the same as that of GFRP layer 2. The fiber material impregnated with epoxy resin is wound around the surface of GFRP layer 2 at a certain angle until the set thickness is reached.

[0043] Step 7: Overall curing: Real-time monitoring of temperature and time to ensure that the resin is fully cured and achieves the required mechanical properties. Figure 3 Smart composite reinforcement shown.

[0044] Example 2

[0045] like Figure 4 As shown, this embodiment provides a method for operating and maintaining a concrete component using the above-mentioned intelligent composite reinforcement. The method for operating and maintaining a concrete component using the intelligent composite reinforcement specifically includes:

[0046] Step S1: Determine the target bearing capacity, target ductility coefficient, initial structural parameters and cross-sectional area ratio of the concrete component.

[0047] In this embodiment, the concrete component is composed of at least intelligent composite reinforcement, bottom stress reinforcement and concrete pouring, and may also involve different structural reinforcements such as stirrups and angle reinforcements; the cross-sectional area ratio ζ is the cross-sectional area of ​​the CFRP layer and the total cross-sectional area of ​​the reinforcement A. s The ratio of the total cross-sectional area of ​​steel bars A s The sum of the cross-sectional areas of the inner core steel bars and the bottom stress reinforcements; structural parameters include: cross-sectional dimensions (cross-sectional width b, cross-sectional height h) and material parameters (concrete strength grade f c , concrete tensile strength f t , ultimate compressive strain of concrete ε cu, steel bar yield strength f y (refers to the yield strength of the inner core steel bar / bottom stress bar, the two are the same), steel bar elastic modulus E s wait).

[0048] Step S2: Based on the initial structural parameters of the concrete component, determine the initial total cross-sectional area of ​​the steel bars.

[0049] In this embodiment, step S2 specifically includes:

[0050] Step S21: determining the failure mode of the concrete component (the failure mode in this embodiment is that the intelligent composite reinforcement yields first and then the concrete is crushed).

[0051] Step S22: Based on the initial structural parameters of the concrete component, the minimum and maximum steel reinforcement areas required by the concrete component in the failure mode are calculated. Specifically:

[0052] A smin =b×h×ρ min ;

[0053] A smax =b×h×ρ max ;

[0054]

[0055] Where A smin is the minimum steel bar area, A smax is the maximum reinforcement area, ρ min is the minimum reinforcement ratio, ρ max is the maximum reinforcement ratio, ξ b is the relative limit compression zone height, and α1 is an empirical parameter.

[0056] Step S23: Based on the minimum steel bar area and the maximum steel bar area, set the initial total cross-sectional area of ​​the steel bars. Specifically:

[0057] A smin ≤A s ≤A smax .

[0058] Step S3: Based on the initial structural parameters, cross-sectional area ratio, and total cross-sectional area of ​​the concrete component, the actual bearing capacity and ductility coefficient of the concrete component are calculated. According to the target bearing capacity and target ductility coefficient, the initial total cross-sectional area, cross-sectional area ratio, and structural parameters of the steel bars are corrected to obtain the basic total cross-sectional area of ​​the steel bars, the basic cross-sectional area ratio, and the basic structural parameters.

[0059] In this embodiment, step S3 specifically includes:

[0060] Step S31: Based on the initial structural parameters of the concrete component, the total cross-sectional area and the cross-sectional area ratio of the steel bars, the yield curvature and peak curvature of the concrete component, as well as the peak strain of the smart composite bar are calculated.

[0061] Specifically, based on the equilibrium condition and the stress-strain relationship of the material, the equation is established:

[0062] C = T;

[0063] C=0.85×f c ×b×β1×c1;

[0064] T=A s ×f y ;

[0065] Where C is the compressive stress in concrete, T is the tensile stress in steel, β1 is an empirical parameter, and c1 is the first neutral axis depth. Solve the equation C = T to find the first neutral axis depth c1.

[0066] Furthermore, the yield curvature u of the concrete member is calculated y :

[0067]

[0068] Where, ε y is the yield strain of the steel bar.

[0069] When the concrete and steel bars reach their respective ultimate strains simultaneously, the second neutral axis depth c2 is determined by iteratively solving the following equation:

[0070] C = T;

[0071] C=0.85×f c ×b×β1×c2;

[0072] T=A s1 ×σ s1 +A s2 ×σ s2 ;

[0073] Where A s1 is the cross-sectional area of ​​the bottom reinforcement, A s2 is the cross-sectional area of ​​the CFRP layer and the inner core steel bar, σ s1 is the actual stress of the bottom reinforcement, σ s2 is the actual stress of the smart composite reinforcement. Solve the equation C = T to find the second neutral axis depth c2.

[0074] Furthermore, the peak strain ε of the smart composite reinforcement is calculated s :

[0075]

[0076] h0 = h - a;

[0077] if ε s > ε y , then σ s1 = f y , where h0 is the effective height of the cross section, a is the thickness of the protective layer, ζ is the cross-sectional area ratio, E f is the elastic modulus of the CFRP layer, and ε u is the fracture strain of the CFRP layer.

[0078] Further, the peak curvature u p of the concrete member is calculated.

[0079]

[0080] Step S32: When the peak strain of the smart composite bar does not satisfy the first set condition, the initial total cross-sectional area of the steel bar is corrected to obtain a first total cross-sectional area of the steel bar.

[0081] Specifically, the first set condition is greater than the yield strain ε y of the steel bar and less than the fracture strain ε u of the CFRP layer. If the peak strain of the smart composite bar does not satisfy the first set condition, the initial total cross-sectional area of the steel bar is continuously corrected until the peak strain of the smart composite bar satisfies the first set condition, and the total cross-sectional area of the steel bar when the first set condition is satisfied is taken as the first total cross-sectional area of the steel bar.

[0082] Step S33: Based on the peak strain of the smart composite bar and the initial cross-sectional area ratio of the concrete member, the actual bearing capacity of the concrete member is calculated, and when the actual bearing capacity of the concrete member is less than the target bearing capacity, the first total cross-sectional area of the steel bar is corrected to obtain a basic total cross-sectional area of the steel bar.

[0083] Specifically, the calculation formula of the bearing capacity is:

[0084]

[0085] In the formula, M is the bearing capacity, f y1 is the yield stress of the bottom force bar (f y1 = f y ), and f y2 is the yield stress of the smart composite bar

[0086] If the actual bearing capacity of the concrete component is less than the target bearing capacity, the total cross-sectional area of ​​the first steel bar needs to be continuously revised until the actual bearing capacity of the concrete component is greater than or equal to the target bearing capacity, and the total cross-sectional area of ​​the first steel bar when it is greater than or equal to the target bearing capacity is used as the total cross-sectional area of ​​the basic steel bar.

[0087] Step S34: Calculate the ratio of the peak curvature to the yield curvature of the concrete component to obtain the actual ductility coefficient of the concrete component.

[0088]

[0089] Where u is the ductility coefficient.

[0090] Step S35: When the actual ductility coefficient of the concrete component is less than the target ductility coefficient, the initial cross-sectional area ratio is corrected to obtain the basic cross-sectional area ratio; when the actual ductility coefficient of the concrete component has no solution, the initial structural parameters are corrected to obtain the basic structural parameters.

[0091] Specifically, if the actual ductility coefficient of a concrete component is less than the target ductility coefficient, the initial cross-sectional area ratio needs to be continuously revised until the actual ductility coefficient of the concrete component is greater than or equal to the target ductility coefficient. The cross-sectional area ratio when it is greater than or equal to the target ductility coefficient is used as the base cross-sectional area ratio. In addition, the actual ductility coefficient of a concrete component may have no solution (such as when the denominator in the ductility coefficient calculation formula is 0). If such a situation occurs, the initial structural parameters need to be continuously revised and the actual ductility coefficient of the concrete component recalculated until the actual ductility coefficient of the concrete component is greater than or equal to the target ductility coefficient. The structural parameters when it is greater than or equal to the target ductility coefficient are used as the base structural parameters.

[0092] Step S4: Determine the initial current density based on the target service life of the concrete component.

[0093] In this embodiment, the current density is determined by the formula:

[0094]

[0095] Where i is the current density, k is the adjustment factor, Q is the total electric flux of the CFRP layer calculated based on the target service life of the concrete component, and t is the time from the start of service to the start of cathodic protection of the concrete component.

[0096] Step S5: Based on the initial current density, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated, and according to the target bearing capacity and target ductility coefficient, the initial current density is corrected to obtain the basic current density.

[0097] In this embodiment, step S5 specifically includes:

[0098] Step S51: Based on the initial current density, the tensile strength of the bottom reinforcement and the reduced cross-sectional area of ​​the CFRP layer are calculated when the concrete component reaches the target service life under cathodic protection, and the first tensile strength of the bottom reinforcement and the first reduced cross-sectional area of ​​the CFRP layer are obtained.

[0099]

[0100] Where, is the first tensile strength of the bottom reinforcement, is the first cross-sectional area reduced by the CFRP layer, f1(·) is the first tensile strength calculation function, f2(·) is the first cross-sectional area calculation function, ρ is the corrosion rate of the bottom reinforcement, T is the target service life, and i0 is the initial current density.

[0101] Step S52: Calculating a first cross-sectional area ratio after the CFRP layer is reduced based on the first cross-sectional area of ​​the CFRP layer, the total cross-sectional area of ​​the foundation steel bars, and the foundation cross-sectional area ratio.

[0102] Specifically, the cross-sectional area of ​​the initial CFRP layer can be determined by multiplying the total cross-sectional area of ​​the basic steel bars by the basic cross-sectional area ratio. The cross-sectional area of ​​the initial CFRP layer minus the first cross-sectional area is then deducted from the cross-sectional area of ​​the initial CFRP layer and the ratio is calculated with the total cross-sectional area of ​​the basic steel bars to obtain the first cross-sectional area ratio after the CFRP layer is reduced.

[0103] Step S53: Based on the first tensile strength of the bottom reinforcement and the first cross-sectional area ratio of the CFRP layer after reduction, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated to obtain the first bearing capacity and the first ductility coefficient.

[0104] Specifically, the calculation process of the first bearing capacity and the first ductility coefficient is the same as that of the above step S3. It is only necessary to numerically replace the tensile strength and cross-sectional area ratio of the bottom stress reinforcement in step S3 and re-execute the above process to obtain the first bearing capacity and the first ductility coefficient.

[0105] Step S54: When the first bearing capacity is less than the target bearing capacity, or the first ductility coefficient is less than the target ductility coefficient, the initial current density is corrected to obtain a basic current density.

[0106] If the first bearing capacity is less than the target bearing capacity, or the first ductility coefficient is less than the target ductility coefficient, then the initial current density needs to be continuously revised until the first bearing capacity is greater than or equal to the target bearing capacity, and the first ductility coefficient is greater than or equal to the target ductility coefficient. The current density when this condition is met is used as the basic current density.

[0107] Step S6: determining the corrosion growth rate of the bottom reinforcement bars in the concrete component; when the corrosion growth rate of the bottom reinforcement bars is not within a set speed range, correcting the basic current density to obtain the optimal current density.

[0108] Specifically, if Figure 5 As shown in the figure, first calculate the corrosion growth rate λ of the bottom reinforcement according to the corrosion rate of the bottom reinforcement at different times:

[0109]

[0110] Where ρ″ and ρ' are the corrosion rates of the bottom reinforcement at different times, and Δt is the time difference. The speed range is set to (λ0,λ t ), λ0 is the corrosion growth rate of the bottom reinforcement without cathodic protection, λ t It is the corrosion growth rate of the bottom reinforcement under cathodic protection and at the maximum current density that does not affect the seismic performance of the concrete member.

[0111] Furthermore, if the corrosion growth rate of the bottom reinforcement is not within (λ0,λ t ), then it is necessary to continuously revise the basic current density according to the curve of the corrosion growth rate of the bottom stress reinforcement and the current density, until the corrosion growth rate of the bottom stress reinforcement is within (λ0,λ t ) and the current density at this time is taken as the optimal current density.

[0112] Step S7: Based on the optimal current density, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated, and according to the target bearing capacity and target ductility coefficient, the foundation cross-sectional area ratio and foundation structural parameters are corrected to obtain the optimal cross-sectional area ratio and optimal structural parameters.

[0113] In this embodiment, step S7 specifically includes:

[0114] Step S71: Based on the optimal current density, the tensile strength of the bottom reinforcement and the reduced cross-sectional area of ​​the CFRP layer are calculated when the concrete component reaches the target service life under cathodic protection, and the second tensile strength of the bottom reinforcement and the second reduced cross-sectional area of ​​the CFRP layer are obtained.

[0115]

[0116] Where, is the second tensile strength of the bottom reinforcement, is the second cross-sectional area reduced by the CFRP layer, g1(·) is the second tensile strength calculation function, g2(·) is the second cross-sectional area calculation function, and i1 is the optimal current density.

[0117] Step S72: Calculate the second sectional area ratio of the CFRP layer after reduction based on the second sectional area of the CFRP layer after reduction, the total sectional area of the basic steel bars, and the basic sectional area ratio.

[0118] Specifically, the initial sectional area of the CFRP layer can be determined by multiplying the total sectional area of the basic steel bars and the basic sectional area ratio, and the second sectional area ratio of the CFRP layer after reduction can be calculated by subtracting the second sectional area from the initial sectional area of the CFRP layer and then dividing the result by the total sectional area of the basic steel bars.

[0119] Step S73: Calculate the bearing capacity and the ductility coefficient of the concrete member when it reaches the target service life under cathodic protection based on the second tensile strength of the bottom force bar and the second sectional area ratio of the CFRP layer after reduction, to obtain the second bearing capacity and the second ductility coefficient.

[0120] Specifically, the calculation process of the second bearing capacity and the second ductility coefficient is the same as that of step S3, and only the tensile strength and the sectional area ratio of the bottom force bar in step S3 need to be replaced with numerical values, and the second bearing capacity and the second ductility coefficient can be obtained by re-executing the above process.

[0121] Step S74: When the second bearing capacity is less than the target bearing capacity, correct the basic sectional area ratio to obtain the optimal sectional area ratio; when the second ductility coefficient has no solution, correct the basic structural parameters to obtain the optimal structural parameters.

[0122] If the second bearing capacity is less than the target bearing capacity, the basic sectional area ratio needs to be continuously corrected until the second bearing capacity is greater than or equal to the target bearing capacity, and the basic sectional area ratio at this time is taken as the optimal sectional area ratio. If the second ductility coefficient has no solution (the denominator of the second ductility coefficient is 0), the basic structural parameters need to be continuously corrected, and the second ductility coefficient needs to be recalculated until the second bearing capacity is greater than or equal to the target bearing capacity, and the basic structural parameters at this time are taken as the optimal structural parameters.

[0123] Step S8: Construct the concrete member based on the total sectional area of the basic steel bars, the optimal sectional area ratio, and the optimal structural parameters, and cathodically protect the concrete member with the optimal current density.

[0124] Specifically, the optimal cross-sectional area of the CFRP layer can be obtained by multiplying the total cross-sectional area of the base steel bars and the optimal cross-sectional area ratio. To further determine the optimal thickness of the CFRP layer, the optimal cross-sectional area of the CFRP layer can be regarded as the area of a circular ring, the cross-sectional area of the smart composite bar can be regarded as the area of a large circle, and the cross-sectional area of the GFRP layer and the inner core steel bars can be regarded as the area of a small circle. The difference between the area of the large circle and the area of the small circle is the optimal cross-sectional area of the CFRP layer. The optimal thickness of the CFRP layer can be determined by the area formula of the circle. The CFRP layer with the optimal thickness can serve as an effective anode material. In addition, the steel bars in the concrete member can be reasonably configured according to the total cross-sectional area of the base steel bars and the optimal cross-sectional area ratio, and the concrete member can be constructed in combination with the optimal structural parameters. The constructed concrete member can be effectively cathodically protected by using the optimal current density, thereby prolonging the service life of the concrete member.

[0125] In summary, the smart composite bar applied in the present application can reinforce the concrete member and improve the ultimate bearing capacity thereof. Meanwhile, the CFRP layer on the surface of the smart composite bar serves as an anode material for cathodic protection of the concrete member, and the GFRP layer inside the smart composite bar serves as an insulation layer to effectively prevent damage to the inner core steel bars. The optical fiber embedded in the groove of the inner core steel bar can also cooperate with the demodulator to achieve strain monitoring and sensing. In addition, since the loss of the anode material affects the effect of cathodic protection to some extent during the cathodic protection process of the concrete member, the determination of the thickness of the CFRP layer of the smart composite bar is crucial to the cathodic protection. Moreover, whether the current density is appropriate also affects the progress of the cathodic protection. The concrete member operation and maintenance method applied in the present application not only determines the effective thickness of the CFRP layer, but also determines the effective current density during the cathodic protection process. By reasonably configuring the cross-sectional areas of the bottom load-bearing bars, the inner core steel bars, and the CFRP layer in the concrete member, the strength of the concrete member can be effectively improved. Meanwhile, under the cathodic protection of the effective current density, the service life of the concrete member can also be prolonged.

[0126] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0127] The principles and implementation manners of the present application are described by using specific examples. The above description of the embodiments is only used to help understand the method and core idea of the present application. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method for operating and maintaining a concrete component using intelligent composite reinforcement, characterized in that: The intelligent composite reinforcement comprises at least an inner core steel bar, a GFRP layer and a CFRP layer arranged in sequence from the inside to the outside; The inner core steel bar is provided with a groove; an optical fiber covered with a polyethylene protective sheath is embedded in the groove; the outer side of the inner core steel bar after embedding the optical fiber is wrapped with a GFRP layer of a first set thickness; the outer side of the GFRP layer is wrapped with a CFRP layer of a second set thickness; The inner core steel bar is used to provide mechanical support for the smart composite bar; the optical fiber is used to cooperate with the demodulator to complete the strain sensing of the smart composite bar; the GFRP layer is used to protect the inner core steel bar from current corrosion; The CFRP layer is used to serve as an anode material for cathodic protection; The operation and maintenance methods of concrete components using intelligent composite reinforcement include: Determining a target bearing capacity, target ductility coefficient, initial structural parameters, and cross-sectional area ratio of a concrete component; the concrete component is composed of at least smart composite reinforcement, bottom stress reinforcement, and concrete; the cross-sectional area ratio is the ratio of the cross-sectional area of ​​the CFRP layer to the total cross-sectional area of ​​the reinforcement; the total cross-sectional area of ​​the reinforcement is the sum of the cross-sectional areas of the inner core reinforcement and the bottom stress reinforcement; Based on the initial structural parameters of the concrete component, determine the initial total cross-sectional area of ​​the steel bars; Calculating the actual bearing capacity and ductility coefficient of the concrete member based on the initial structural parameters, cross-sectional area ratio, and total cross-sectional area of ​​the steel bars of the concrete member, and correcting the initial total cross-sectional area, cross-sectional area ratio, and structural parameters of the steel bars according to the target bearing capacity and the target ductility coefficient to obtain the basic total cross-sectional area of ​​the steel bars, the basic cross-sectional area ratio, and the basic structural parameters; Determine the initial current density based on the target service life of the concrete component; Based on the initial current density, calculating the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection, and correcting the initial current density according to the target bearing capacity and the target ductility coefficient to obtain a basic current density; determining a corrosion growth rate of bottom reinforcement bars in a concrete member, and when the corrosion growth rate of the bottom reinforcement bars is not within a set speed range, modifying the basic current density to obtain an optimal current density; Based on the optimal current density, calculating the bearing capacity and ductility coefficient of the concrete component when it reaches a target service life under cathodic protection, and correcting the foundation cross-sectional area ratio and the foundation structural parameters according to the target bearing capacity and the target ductility coefficient to obtain an optimal cross-sectional area ratio and optimal structural parameters; A concrete component is constructed based on the total cross-sectional area of ​​the basic steel bars, the optimal cross-sectional area ratio and the optimal structural parameters, and cathodic protection is performed on the concrete component using the optimal current density.

2. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: The second set thickness is greater than the first set thickness.

3. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: The structural parameters include: cross-sectional dimensions and material parameters; the cross-sectional dimensions include: cross-sectional width and cross-sectional height; the material parameters include at least: concrete strength grade, concrete tensile strength and steel bar yield strength.

4. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: Based on the initial structural parameters of the concrete component, determine the initial total cross-sectional area of ​​the steel bars, including: Determine the failure modes of concrete components; Based on the initial structural parameters of the concrete component, the minimum and maximum steel reinforcement areas required for the concrete component under the failure mode are calculated; An initial total cross-sectional area of ​​the steel bars is set based on the minimum steel bar area and the maximum steel bar area.

5. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: Based on the initial structural parameters, cross-sectional area ratio, and total cross-sectional area of ​​the concrete component, the actual bearing capacity and ductility coefficient of the concrete component are calculated. According to the target bearing capacity and the target ductility coefficient, the initial total cross-sectional area, cross-sectional area ratio, and structural parameters of the steel bars are corrected to obtain the basic total cross-sectional area of ​​the steel bars, the basic cross-sectional area ratio, and the basic structural parameters, which specifically include: Based on the initial structural parameters of the concrete member, the total cross-sectional area of ​​the steel bars and the cross-sectional area ratio, the yield curvature and peak curvature of the concrete member, as well as the peak strain of the smart composite reinforcement, are calculated. When the peak strain of the smart composite reinforcement does not meet the first set condition, the initial total cross-sectional area of ​​the reinforcement is corrected to obtain a first total cross-sectional area of ​​the reinforcement; the first set condition is greater than the yield strain of the reinforcement and less than the fracture strain of the CFRP layer; Calculating the actual bearing capacity of the concrete member based on the peak strain of the smart composite reinforcement and the initial cross-sectional area ratio of the concrete member, and when the actual bearing capacity of the concrete member is less than the target bearing capacity, correcting the total cross-sectional area of ​​the first reinforcement to obtain the total cross-sectional area of ​​the foundation reinforcement; Calculate the ratio of the peak curvature to the yield curvature of the concrete component to obtain the actual ductility coefficient of the concrete component; When the actual ductility coefficient of the concrete component is less than the target ductility coefficient, the initial cross-sectional area ratio is corrected to obtain the basic cross-sectional area ratio; when the actual ductility coefficient of the concrete component has no solution, the initial structural parameters are corrected to obtain the basic structural parameters.

6. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: The formula for determining current density is: ； Where, is the current density, is the adjustment coefficient, is the total electric flux of the CFRP layer calculated based on the target service life of the concrete component, It is the time from the start of service of the concrete component to the start of cathodic protection.

7. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: Based on the initial current density, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated, and according to the target bearing capacity and the target ductility coefficient, the initial current density is corrected to obtain the basic current density, specifically including: Based on the initial current density, the tensile strength of the bottom reinforcement and the reduced cross-sectional area of ​​the CFRP layer are calculated when the concrete component reaches the target service life under cathodic protection. The first tensile strength of the bottom reinforcement and the first reduced cross-sectional area of ​​the CFRP layer are obtained. Calculate the first cross-sectional area ratio after the CFRP layer is reduced based on the first cross-sectional area reduced by the CFRP layer, the total cross-sectional area of ​​the foundation steel bars, and the cross-sectional area ratio of the foundation; Based on the first tensile strength of the bottom reinforcement and the first cross-sectional area ratio after the CFRP layer is reduced, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated to obtain the first bearing capacity and the first ductility coefficient; When the first bearing capacity is less than the target bearing capacity, or the first ductility coefficient is less than the target ductility coefficient, the initial current density is corrected to obtain a basic current density.

8. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: The setting speed range is ( );in, is the corrosion growth rate of the bottom reinforcement without cathodic protection, It is the corrosion growth rate of the bottom reinforcement under cathodic protection and at the maximum current density that does not affect the seismic performance of the concrete member.

9. The operation and maintenance method of concrete components using intelligent composite reinforcement according to claim 1, characterized in that: Based on the optimal current density, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated, and according to the target bearing capacity and the target ductility coefficient, the foundation cross-sectional area ratio and the foundation structural parameters are corrected to obtain the optimal cross-sectional area ratio and the optimal structural parameters, specifically including: Based on the optimal current density, calculating the tensile strength of the bottom reinforcement and the reduced cross-sectional area of ​​the CFRP layer when the concrete component reaches the target service life under cathodic protection, and obtaining the second tensile strength of the bottom reinforcement and the second reduced cross-sectional area of ​​the CFRP layer; Calculate the second cross-sectional area ratio after the CFRP layer is reduced based on the second cross-sectional area reduced by the CFRP layer, the total cross-sectional area of ​​the foundation steel bars, and the cross-sectional area ratio of the foundation; Based on the second tensile strength of the bottom reinforcement and the second cross-sectional area ratio after the CFRP layer is reduced, the bearing capacity and ductility coefficient of the concrete component when it reaches the target service life under cathodic protection are calculated to obtain the second bearing capacity and second ductility coefficient; When the second bearing capacity is less than the target bearing capacity, the foundation cross-sectional area ratio is modified to obtain an optimal cross-sectional area ratio; when there is no solution for the second ductility coefficient, the foundation structural parameters are modified to obtain optimal structural parameters.

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