Annular concrete pole connecting piece anti-corrosion construction technology

Abstract

The invention relates to the technical field of corrosion prevention of concrete pole connecting pieces, and provides an annular concrete pole connecting piece corrosion prevention construction technology which comprises the steps that firstly, drawing force, bonding strength and concrete wrapping thickness are accurately checked based on the field environment and experimental data, and it is ensured that design parameters are not excessively conserved and have no potential safety hazards; 2, strictly calculating the anchoring length of the thread at the end part of the reinforcing steel bar and marking a processing drawing, so that the thread section gives full play to bonding bearing and is convenient to assemble on site; thirdly, through graded torque control of primary tightening seam arrangement and final tightening pre-tightening, the nut and the threaded section are tightly engaged like being attached to a rubber ring, meanwhile, the loosening risk is eradicated through a locking gasket, and no high-temperature electric welding damages a zinc coating in the whole process; and 4, centrifugally pouring concrete in a factory to form a uniform and compact'armor 'package, adjusting by combining dynamically checked graded curing time and environment temperature, and finally detecting the thickness, internal defects and corrosion resistance in all directions by using ultrasonic waves, radar and salt spray tests.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion protection of concrete pole connectors, and in particular to an anti-corrosion construction process for an annular concrete pole connector. Background Art

[0002] Annular concrete poles are made of sand, stone, cement, steel, and admixtures. They are formed through high-speed centrifugal molding and have the advantages of strong bearing capacity, low cost, smooth and beautiful surface, long service life, and no maintenance. They are mainly used for overhead power lines and line facilities such as communications and railways. Annular concrete poles: When line construction requires taller and longer annular concrete poles, but the poles are too long and cannot be transported due to road conditions, the poles must be produced and processed in sections to solve the transportation problem. After transportation to the site, they are assembled for line construction. To ensure the safety of line operation, according to national and industry standards, the connectors of the assembled poles must be effectively treated with anti-corrosion. In the existing production process of assembled poles, the connecting flanges must be pre-installed in advance. The connecting flanges of the assembled poles are connected to the main steel bars inside the pole body before concrete is poured and formed to produce a complete finished pole. The method currently adopted by annular concrete pole manufacturers is to weld the main steel bars inside the pole to the connecting flanges to form a whole.

[0003] In traditional electric welding processes, the arc heat effect of around 7000°C between the flange and the main steel bars inside the pole will inevitably cause the hot-dip galvanized layer to melt and peel off, destroying the original anti-corrosion protection. During the subsequent concrete wrapping and service process, this exposed steel surface is susceptible to water vapor and electrochemical corrosion, ultimately reducing the durability of the entire connection and posing a safety hazard to line operation. Summary of the Invention

[0004] The purpose of the present invention is to provide an anti-corrosion construction process for an annular concrete pole connector to solve the problem that in the traditional electric welding process, the flange and the main steel bars inside the pole are inevitably melted and peeled off under the arc heat effect of about 7000°C, thereby destroying the original anti-corrosion protection; during the subsequent concrete wrapping and service process, this exposed steel surface is susceptible to water vapor and electrochemical corrosion, ultimately reducing the durability of the entire connector and burying a safety hazard in the operation of the line.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: a kind of anti-corrosion construction process of annular concrete pole connector,

[0006] Collect raw materials and conduct preliminary cleaning of raw materials;

[0007] Process the raw materials and clean the surface;

[0008] Assemble the processed raw materials, perform graded pre-tightening, and record;

[0009] The assembled materials are centrifugally poured, graded and cured, and the finished products are subjected to non-destructive testing.

[0010] As a preferred embodiment, the raw materials include: hot-dip galvanized flange, hanging ring, main steel bar, nut, lock washer, concrete raw material, epoxy mortar;

[0011] The specific steps of the preliminary cleaning are:

[0012] Take a special degreaser or industrial alcohol and soak a lint-free cloth;

[0013] Rinse the surface you just wiped with clean water or a low-pressure water gun to wash away any remaining degreaser or alcohol;

[0014] For light rust or scratches, use a scouring pad to wipe until the metal turns to its original color;

[0015] Rinse again; let dry.

[0016] As a preferred embodiment, the specific steps of processing the raw materials are as follows:

[0017] Fix the ends of the main steel bars on the CNC machine tool and set the processing parameters;

[0018] Start the machine tool, cut out the thread segment, and remove it;

[0019] Fix the hanging ring on the workbench of the drilling machine and ensure that the hole is aligned with the designed center;

[0020] Replace the chamfering tool and make a small chamfer of 1-2mm on the edge of the hole;

[0021] Clean the processed raw materials;

[0022] As a preferred embodiment, the assembly includes the following steps:

[0023] Install an adjustable guide sleeve on the outside of the reinforcement ring; insert the threaded section main steel bar into the reinforcement ring hole, and adjust the guide sleeve so that the reinforcement ring and the threaded section main steel bar are concentric.

[0024] As a preferred embodiment, the graded pre-tightening comprises the following steps:

[0025] Use a manual torque wrench to connect the nut to the main steel bar of the threaded section, calculate the initial tightening torque, and maintain the torque for 30 seconds to allow the contact surface to produce initial deformation;

[0026] Take a hydraulic wrench, calculate the final tightening torque, use the hydraulic wrench to connect the nut to the main steel bar of the threaded section, and maintain the final tightening torque for 10 seconds to ensure there is no rebound;

[0027] And record the initial tightening torque and final tightening torque of the assembly components;

[0028] The calculation formulas for the initial tightening torque and the final tightening torque are: Where: T des is the total design torque, T init is the initial tightening torque, T final is the final tightening torque, L is the length of the threaded anchor, C is the thickness of the concrete cover, and k is the empirical adjustment coefficient, which is between 0.5 and 1.0.

[0029] As a preferred embodiment, the centrifugal casting steps include:

[0030] Place the assembled components vertically in a centrifugal mold, start the centrifuge, pour in concrete, and rotate at 300-400 rpm;

[0031] After reaching the pouring volume, continue centrifugation for 60 seconds and let it rest for 1 hour to prepare the protective layer.

[0032] As a preferred embodiment, the graded curing comprises the following steps:

[0033] For initial maintenance, cover with film, humidity ≥ 90%, temperature 20-25℃, for 24 hours;

[0034] Calculate and adjust the subsequent routine maintenance time. The formula is: Where: T min is the shortest required curing time, t0 is the curing time under reference conditions, C0 is the thickness of the protective layer under reference conditions, T0 is the temperature under reference conditions, T amb is the actual ambient temperature, m and α are empirical coefficients, reflecting the gain effect of thickness on curing time and temperature sensitivity respectively.

[0035] As a preferred embodiment, the specific steps of the non-destructive testing are:

[0036] Scan the finished product circumferentially to check for cracks and pores.

[0037] The beneficial effects of the present invention are:

[0038] 1. The first step is to accurately check the pull-out force, bond strength and concrete wrap thickness based on the on-site environment and experimental data to ensure that the design parameters are neither overly conservative nor leave safety hazards; the second step is to strictly calculate the thread anchorage length of the steel bar end and mark the processing drawings, so that the thread segment can fully exert the bond load and facilitate on-site assembly; the third step is to use the graded torque control of "initial tightening and pre-tightening" to tightly fit the nut and thread segment like a rubber ring, and at the same time use locking washers to eliminate the risk of loosening. The whole process does not involve high-temperature electric welding to damage the galvanized layer; the fourth step is to centrifugally pour concrete in the factory to form a uniform and dense "armor" wrap, and combine the graded curing time and ambient temperature adjustment of dynamic verification. Finally, ultrasonic, radar and salt spray tests are used to comprehensively detect thickness, internal defects and corrosion.

[0039] Legend

[0040] Figure 1 The figure is a flow chart of the anti-corrosion construction process of an annular concrete pole connector. DETAILED DESCRIPTION

[0041] In order to make the technical means, creative features, purpose and efficacy of the present invention easy to understand, the present invention is further described below in conjunction with specific examples, but the following examples are only preferred embodiments of the present invention, not all. Based on the examples in the embodiments, other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. The experimental methods in the following examples, unless otherwise specified, are conventional methods, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0042] Example 1: A corrosion-resistant construction process for a ring-shaped concrete pole connector:

[0043] Collecting raw materials and performing preliminary cleaning of the raw materials, including: hot-dip galvanized flanges, hanging rings, main steel bars, nuts, lock washers, concrete raw materials, epoxy mortar, etc.;

[0044] The specific steps of the preliminary cleaning are:

[0045] Take a special degreaser or industrial alcohol, soak a lint-free cloth, and repeatedly wipe the flange, hanging ring, steel bar end face and nut surface, focusing on removing cutting oil, rust residue and fingerprints;

[0046] Rinse the surface you just wiped with clean water or a low-pressure water gun to wash away any remaining degreaser or alcohol. If you used a strong base or acid for degreasing, rinse again with a neutral detergent to ensure the surface has a neutral pH.

[0047] For light rust or scratches, use a scouring pad to wipe until the metal color is restored. For thicker oxide scale or rust layer, use fine sandpaper (#120~#240) to polish until the metallic luster is exposed.

[0048] After rinsing and drying, all hot-dip galvanized flanges, reinforcement rings, steel bars, nuts and washers are quickly degreased, derusted and stored in categories to ensure that the surface of each component is free of oil and rust and the dimensions are qualified, laying a clean and stable foundation for subsequent machining and anchoring.

[0049] Example 2, based on Example 1, further explanation is that the raw materials are processed and the surface is cleaned. The specific steps of processing the raw materials are as follows:

[0050] Fix the ends of the main steel bars on the CNC machine tool, set the processing parameters, thread length, pitch and nut matching, cutting depth and feed speed according to the steel bar grade;

[0051] Start the machine tool, cut out the thread segment, and remove it;

[0052] Fix the reinforcement ring on the workbench of the drilling machine, ensure that the hole position is aligned with the designed center line, and use a carbide drill bit that is 3-5mm larger than the outer diameter of the main steel bar of the threaded section, and drill through to the marked depth;

[0053] Replace the chamfering tool and make a small chamfer of 1-2mm on the edge of the hole;

[0054] The processed raw materials are cleaned to remove chips, iron filings, and dust. A 300mm thread segment is precisely machined out of the end of the steel bar. A guide hole is precisely drilled in the rebar ring to match the thread and chamfered to prevent cracking. The chips and processing oil are then blown away with high-pressure air and wiped with alcohol to ensure that the thread valley and the inner wall of the hole are free of debris, providing a reliable matching surface for the "thread + nut" mechanical anchoring.

[0055] Example 3, based on Example 2, it is further explained that the processed raw materials are assembled, graded and pre-tightened, and recorded. The assembly includes the following steps:

[0056] Install an adjustable guide sleeve on the outside of the reinforcement ring; insert the threaded main steel bar into the reinforcement ring hole, and adjust the guide sleeve so that the reinforcement ring and the threaded main steel bar are concentric. The graded pre-tightening includes the following steps:

[0057] Use a manual torque wrench to connect the nut to the main steel bar of the threaded section, calculate the initial tightening torque, and maintain the torque for 30 seconds to allow the contact surface to produce initial deformation;

[0058] Take a hydraulic wrench, calculate the final tightening torque, use the hydraulic wrench to connect the nut to the main steel bar of the threaded section, and maintain the final tightening torque for 10 seconds to ensure there is no rebound;

[0059] And record the initial tightening torque and final tightening torque of the assembly components;

[0060] The calculation formulas for the initial tightening torque and the final tightening torque are: Where: T des is the total design torque, the final tightening torque required for the entire thread + nut connection to achieve the required design preload, T init is the initial tightening torque, T final is the final tightening torque, L is the thread anchor length, that is, the effective length of the thread section on the main steel bar wrapped by concrete to provide bonding, C is the thickness of the concrete cover, k is the empirical adjustment coefficient, usually 0.5 to 1.0, assuming T des is 660Nm, the threaded anchor length L is 300mm, the concrete cover thickness C is 50mm, and the empirical adjustment coefficient k is 0.2. First calculate =-0.2×300÷50=-1.2, e -1.2 Approximately equal to 0.301, the initial tightening torque is T init =660(1-0.301)≈660×0.699≈461m; that is, the initial tightening reaches about 460Nm to achieve the seam locking, and the final tightening torque is T final =660-461=199Nm, that is, the final tightening is 199Nm, forming the final prestress, initial tightening torque T init First, it is used to eliminate the small gap between the nut and the thread and the uneven contact surface, to prevent a large torque from acting directly on the interface between the concrete and the steel bar, to reduce local stress concentration and micro cracks, and then use the final tightening torque T after the gap is eliminated. final Apply the required design preload force to lock the nut and thread segment together through friction and concrete bonding, maintaining long-term stability. After concentric insertion through the guide sleeve, first use a manual torque wrench to slowly tighten the joint according to the calculated initial tightening torque (about 460N·m); then use an electric or hydraulic wrench to increase the remaining final tightening torque (about 200N·m) and tighten the lock washer to prevent loosening. The error is controlled within ±5%, ensuring that each connector can achieve stable prestressed anchoring without high-temperature electric welding interfering with the galvanized layer.

[0061] Example 4, based on Example 3, it is further explained that the assembled materials are centrifugally poured, graded curing is performed, and non-destructive testing is performed on the finished product. The specific steps of the centrifugal pouring include:

[0062] Place the assembled components vertically in a centrifugal mold, start the centrifuge, pour in concrete, and rotate at 300-400 rpm;

[0063] After reaching the pouring volume, continue centrifugation for 60 seconds and let it rest for 1 hour to prepare the protective layer. The graded curing includes the following steps:

[0064] For initial curing, cover with film and keep humidity ≥90% to minimize surface cracks and ensure hydration. Then enter the regular curing stage at 20-25℃ for 24 hours.

[0065] Calculate and adjust the subsequent routine maintenance time. The formula is: Where: T min is the shortest required curing time, t0 is the curing time under reference conditions, C0 is the thickness of the protective layer under reference conditions, T0 is the temperature under reference conditions, T amb is the actual ambient temperature, m and α are empirical coefficients, reflecting the gain effect of thickness on curing time and temperature sensitivity, respectively. Assuming that the curing time t0 under reference conditions is 7 days, the cover thickness C0 under reference conditions is 40 mm, the concrete cover thickness C is 50 mm, the thickness index m = 1.2, and the temperature sensitivity α is 0.03 °C -1 , the reference temperature T0 is 20℃, the actual ambient temperature T amb At 25°C, T min =7×1.307×0.861≈7.9d. In addition to the 24-hour high-humidity curing on the first day, at least another 8 days of curing are required to ensure the strength and anti-corrosion effect of the concrete. Under different component thicknesses and climatic conditions, the traditional "7-day curing" may be too short (thick components are not strong enough) or too long (thin components waste construction time). This formula can calculate the shortest safe curing days that just meet the design requirements, neither delaying the construction period nor taking risks. The formula can be integrated into the construction plan to automatically generate the curing cycle for each batch of components, improving the coordination efficiency between the factory and the site. The specific steps of the non-destructive testing are as follows: the finished product is scanned circumferentially to check whether it is qualified. If it is unqualified, it is repaired and checked for cracks, air holes, etc. All assembled components are sent to the centrifugal mold, poured and vibrated at 300-400rpm, and set for 60 seconds to form a thickness-controlled, dense and seamless concrete "armor"; after initial setting, it is covered with wet burlap or plastic film and cured at high humidity for 24 hours, and then dynamically adjusted to a minimum curing period of about 8 days according to the thickness of the protective layer and the ambient temperature.

[0066] The first step is to accurately check the pull-out force, bond strength and concrete wrapping thickness based on the on-site environment and experimental data to ensure that the design parameters are neither overly conservative nor leave safety hazards; the second step is to strictly calculate the threaded anchorage length of the steel bar end and mark the processing drawings, so that the threaded section can fully exert the bond load and facilitate on-site assembly; the third step is to use the graded torque control of "initial tightening + final tightening and pre-tightening" to tightly fit the nut and the threaded section like a rubber ring, and at the same time use locking washers to eliminate the risk of loosening. There is no high-temperature electric welding to damage the galvanized layer during the entire process; the fourth step is to centrifugally pour concrete in the factory to form a uniform and dense "armor" wrapping, and combine the dynamically checked graded curing time and ambient temperature adjustment. Finally, ultrasonic, radar and salt spray tests are used to comprehensively detect the thickness, internal defects and corrosion resistance.

[0067] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A corrosion-resistant construction process for an annular concrete pole connector, characterized by: Collect raw materials and conduct preliminary cleaning of raw materials; Process the raw materials and clean the surface; Assemble the processed raw materials, perform graded pre-tightening, and record; The assembled materials are centrifugally poured, graded and cured, and the finished products are subjected to non-destructive testing.

2. The anti-corrosion construction process for annular concrete pole connector according to claim 1, characterized in that: The raw materials include: hot-dip galvanized flange, hanging ring, main steel bar, nut, lock washer, concrete raw material, epoxy mortar; The specific steps of the preliminary cleaning are: Take a special degreaser or industrial alcohol and soak a lint-free cloth; Rinse the surface you just wiped with clean water or a low-pressure water gun to wash away any remaining degreaser or alcohol; For light rust or scratches, use a scouring pad to wipe until the metal turns to its original color; Rinse again; let dry.

3. The anti-corrosion construction process for annular concrete pole connector according to claim 2, characterized in that: The specific steps of processing the raw materials are as follows: Fix the ends of the main steel bars on the CNC machine tool and set the processing parameters; Start the machine tool, cut out the thread segment, and remove it; Fix the hanging ring on the workbench of the drilling machine and ensure that the hole is aligned with the designed center; Replace the chamfering tool and make a small chamfer of 1-2mm on the edge of the hole; Clean the processed raw materials.

4. The anti-corrosion construction process for annular concrete pole connector according to claim 1, characterized in that: The assembly comprises the following steps: Install an adjustable guide sleeve on the outside of the reinforcement ring; insert the threaded section main steel bar into the reinforcement ring hole, and adjust the guide sleeve so that the reinforcement ring and the threaded section main steel bar are concentric.

5. The anti-corrosion construction process for annular concrete pole connector according to claim 4, characterized in that: The graded pre-tightening comprises the following steps: Use a manual torque wrench to connect the nut to the main steel bar of the threaded section, calculate the initial tightening torque, and maintain the torque for 30 seconds to allow the contact surface to produce initial deformation; Take a hydraulic wrench, calculate the final tightening torque, use the hydraulic wrench to connect the nut to the main steel bar of the threaded section, and maintain the final tightening torque for 10 seconds to ensure there is no rebound; And record the initial tightening torque and final tightening torque of the assembly components; The calculation formulas for the initial tightening torque and the final tightening torque are: Where: T des is the total design torque, T init is the initial tightening torque, T final is the final tightening torque, L is the length of the threaded anchor, C is the thickness of the concrete cover, and k is the empirical adjustment coefficient, which is between 0.5 and 1.

0.

6. The anti-corrosion construction process for annular concrete pole connector according to claim 5, characterized in that: The specific steps of centrifugal casting include: Place the assembled components vertically in a centrifugal mold, start the centrifuge, pour in concrete, and rotate at 300-400 rpm; After reaching the pouring volume, continue centrifugation for 60 seconds and let it rest for 1 hour to prepare the protective layer.

7. The anti-corrosion construction process for annular concrete pole connector according to claim 1, characterized in that: The graded maintenance comprises the following steps: For initial maintenance, cover with film, humidity ≥ 90%, temperature 20-25℃, for 24 hours; Calculate and adjust the subsequent routine maintenance time. The formula is: Where: T min is the shortest required curing time, t0 is the curing time under reference conditions, C0 is the thickness of the protective layer under reference conditions, T0 is the temperature under reference conditions, T amb is the actual ambient temperature, m and α are empirical coefficients, reflecting the gain effect of thickness on curing time and temperature sensitivity respectively.

8. The anti-corrosion construction process for annular concrete pole connector according to claim 7, characterized in that: The specific steps of the non-destructive testing are: The finished product is scanned circumferentially to check whether it is qualified. If it is unqualified, it will be repaired.

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