Reinforcing steel bar protection layer positioning method for wall and column vertical structure

Abstract

The invention relates to the technical field of reinforced concrete structure construction, in particular to a steel bar protection layer positioning method for a wall and column vertical structure, which comprises the following steps: according to the specification of a vertical steel bar and the thickness of a designed protection layer, selecting a cushion block with a central hole spiral groove and an outer-layer anti-slip structure, an adaptive iron wire, a clamping seat, a positioning pin and an assembly, and carrying out quality inspection; mounting points are marked on the outer sides of the steel bars, points are arranged at conventional positions according to stable intervals, and stressed parts such as corners are encrypted; iron wires penetrate through cushion block holes and are bound with the steel bars, and the iron wires are embedded into the grooves to prevent slipping with preset torque; positioning pins are attached to the outer layers of the cushion blocks to calibrate the thickness of the cushion blocks; layered die filling is carried out to ensure fitting; and the thickness of a protective layer is detected after mold removal, and the position where deviation exceeds the standard is repaired. The method improves precision and stability, is suitable for multi-specification steel bar and steel / wood formwork scenes, and can solve the problems that in a traditional positioning technology, cushion blocks are prone to sliding, the thickness deviation of a protection layer is large, and the construction quality is unstable.

Description

Technical Field

[0001] This invention belongs to the field of reinforced concrete structure construction technology, specifically relating to a method for positioning the protective layer of reinforcing bars in vertical structures such as walls and columns. Background Technology

[0002] In the field of building construction, vertical load-bearing structures such as walls and columns are the core load-bearing units of concrete buildings, and their long-term durability directly affects the overall safety and service life of the building. According to the "Code for Acceptance of Construction Quality of Concrete Structures", steel bars in vertical structures must retain a 50-100mm concrete cover to isolate them from external moisture and corrosive media. If the thickness of the cover deviates by more than ±5mm, the corrosion rate of the steel bars will increase by 30%-50%, and the service life of the structure will be shortened by 15-20 years. Therefore, controlling the thickness of the cover is a critical aspect of concrete construction.

[0003] Reinforcement cover spacers, serving as positioning and support media between reinforcement bars and formwork, are core auxiliary components ensuring the required cover thickness. Among them, quincunx-shaped concrete spacers have become the mainstream choice for vertical wall and column structures due to their uniform stress distribution and good compatibility with concrete. These traditional spacers are typically designed with a multi-lobed structure, 50-80mm in diameter and 25-30mm thick, with a central through-hole of 8-12mm. They are then fixed to the vertical reinforcement bars by 1.2-1.6mm galvanized iron wire, relying on the fit between the spacer and the formwork to control the cover thickness. However, in actual construction (especially during the concrete pouring and vibration stage), traditional quincunx-shaped concrete spacers suffer from three major technical defects that are difficult to resolve: (1) The spacer blocks are prone to shifting and loosening along the formwork. Vertical structure pouring requires high-frequency vibration (frequency 200-300Hz), but the multi-lobed outer surface of the traditional spacer blocks is a smooth plane with a friction coefficient of only 0.18-0.22 with the formwork, which cannot resist the impact force of vibration. Actual measurements show that after vibration, the probability of the spacer blocks sliding down the formwork or shifting radially along the reinforcing bars exceeds 35%, resulting in a protective layer thickness deviation of more than ±5mm in more than 40% of cases. In some areas, the spacer blocks even fall off and the reinforcing bars stick to the formwork, requiring removal and rework, which increases costs and damages the integrity of the structure.

[0004] (2) The binding wire is prone to slippage and failure. The inner wall of the central through hole of the traditional pad is smooth, and the wire is fixed only by static friction of line contact. During vibration, it is easy to rotate around the axis or slide along the hole wall, with a slippage rate of over 28%. In severe cases, the wire will come out of the hole, causing the pad to lose its positioning function. At the same time, the slippage process may also scratch the concrete of the hole wall, reduce the strength of the pad, and increase the risk of breakage.

[0005] (3) Existing improvement solutions have limited effectiveness. The industry has tried adding protrusions to the surface of the pad and using thick-diameter iron wire, but the former can only increase the coefficient of friction to 0.25-0.28, which is still difficult to resist vibration force; the latter has not solved the fundamental problem of smooth hole walls, and thick iron wire is easy to crack the edge of the through hole of the pad.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems in the prior art, the present invention provides a method for positioning the protective layer of steel bars in vertical structures of walls and columns, which solves the problems of easy slippage of pads, large deviation of protective layer, and low construction efficiency in traditional positioning methods.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A method for locating the concrete cover of reinforcing bars in vertical wall and column structures, comprising: S1. Based on the diameter of the vertical steel bars and the designed thickness of the steel bar protective layer, select suitable anti-slip multi-lobed concrete pads, special binding wires, steel bar positioning brackets and template positioning pins. The inner wall of the central hole of the anti-slip multi-lobed concrete pad is provided with a spiral groove, and the outer surface of the plum blossom petals is provided with an outer anti-slip structure. S2. Mark the installation position of the spacer block on the outside of the vertical reinforcing bar; S3. Pass the special binding wire through the center hole of the anti-slip multi-lobed concrete pad and tie it to the vertical steel bar so that the wire is embedded in the spiral groove of the center hole. S4. Install steel bar positioning brackets on the vertical steel bars on the upper and lower sides of the anti-slip multi-lobed concrete pad to restrict the pad from sliding along the axial direction of the steel bars. S5. Attach template positioning pins to the outer anti-slip structure surface of the anti-slip multi-lobed concrete pad block, calibrate the distance between the positioning pins and the reinforcing bars, and ensure that the design protective layer thickness is met. S6. Install the template so that the inner side of the template fits the outer anti-slip structure of the pad block.

[0009] Furthermore, it also includes: S7. Pouring monitoring and post-pouring verification: Control the vibration operation during concrete pouring, check the thickness of the steel reinforcement protective layer after the formwork is removed, and repair any deviations. The vibration is performed using a vibrating rod, with a distance of ≥100mm between the vibrating rod and the pad, a vibration frequency of 200-300Hz, and a single-point vibration time of 10-15s, in order to solve the problem of pad displacement caused directly by the vibration impact force.

[0010] Furthermore, the thickness of the concrete cover for reinforcing bars is tested using a concrete cover thickness measuring instrument, and the standard is to randomly test 10 points for each column. When the pass rate is ≥95%, it is considered qualified. If the deviation of a single test point exceeds ±5mm, use epoxy resin mortar with a strength of C35 or higher to repair it, so as to solve the problem of the thickness deviation affecting the durability of the structure in the later stage.

[0011] Furthermore, the spacing of the installation positions is as follows: vertical spacing of 500-800mm, horizontal spacing of 300-500mm, and the spacing of the corner steel reinforcement installation points is increased to 300mm.

[0012] Furthermore, the spiral groove that allows the wire to embed into the central hole specifically includes: After wrapping the wire around the rebar twice, thread it back through the center hole and manually tighten it until there is no looseness left. The tightening torque should be ≥5 N·m when checked with a torque wrench.

[0013] Furthermore, step S4 is followed by a card slot installation verification step: Gently pull the rebar positioning bracket by hand to check for looseness; then use a force gauge to test the axial resistance of the bracket to ensure that the resistance is ≥100N. If the resistance does not meet the standard, readjust the position of the bracket until it meets the standard.

[0014] Furthermore, template preprocessing is included before step S6: If it is steel formwork, apply water-based release agent evenly to the inside; if it is wooden formwork, first lay a waterproof membrane on the inside of the formwork and then apply the release agent, let it dry for 30 minutes before installation, in order to solve the problem of formwork sticking to concrete or positioning deviation caused by water absorption and deformation of wooden formwork.

[0015] Furthermore, in step S6, the template inner side is bonded to the outer anti-slip structure of the pad, which is installed in layers from bottom to top. After each layer of template contacts the pad, the installation is paused to check the fit until it is completely sealed before continuing.

[0016] Furthermore, step S1 is followed by a component quality inspection step: Inspect the spiral grooves and outer anti-slip structure of the anti-slip multi-lobed concrete pad; test the breaking strength of the special binding wire; measure the length of the template positioning pins with a digital caliper and reject unqualified components.

[0017] Furthermore, the distance between the calibration positioning pin and the reinforcing bar specifically includes: Using a digital caliper with an accuracy of 0.01mm, measure the distance between the end of the locating pin furthest from the pad and the surface of the vertical reinforcing bar. If the distance deviation exceeds ±1mm, remove the locating pin, clean the surface of the pad again, and then re-align it.

[0018] Compared with existing technologies, the present invention provides a method for positioning the protective layer of reinforcing bars in vertical wall and column structures, comprising: selecting a pad with a spiral groove and an outer anti-slip structure, and matching wire, clamps, and positioning pins, according to the specifications of the vertical reinforcing bars and the designed protective layer thickness; marking installation points on the outside of the reinforcing bars, setting points at stable intervals in conventional locations, and increasing the spacing at corners and other stress-bearing areas; binding the wire to the reinforcing bars through the holes in the pads, using a preset torque to embed the wire into the grooves to prevent slippage; installing clamps on the upper and lower parts of the pads to limit axial sliding, and attaching positioning pins to the outer layer of the pads to calibrate the thickness; layering the formwork to ensure fit; controlling vibration during pouring to prevent displacement; checking the protective layer thickness after demolding, and repairing any deviations. This method improves accuracy and stability, is applicable to various specifications of reinforcing bars and steel / wooden formwork scenarios, and can solve problems such as easy slippage of pads, large deviations in protective layer thickness, and unstable construction quality in traditional positioning technologies. Attached Figure Description

[0019] Figure 1 A flowchart of a method for locating the concrete cover for reinforcing bars provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0021] It should be noted that, unless otherwise specifically stated, the relative arrangement and numerical expressions of the components and steps described in these embodiments should not be construed as limiting the scope of the invention.

[0022] The following description of exemplary embodiments is merely illustrative and is not intended to limit the invention or its application or use in any way. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but where applicable, such techniques, methods, and apparatus should be considered part of this specification.

[0023] Example 1 See Figure 1 , Figure 1 This is a flowchart illustrating a method for locating the protective layer of reinforcing bars in vertical wall and column structures, as proposed in this invention. This method addresses problems such as easy slippage of the spacer blocks, large deviations in the protective layer, and low construction efficiency in traditional positioning methods. Specific steps may include: S1. Based on the diameter of the vertical steel bars and the designed thickness of the steel bar protective layer, select suitable anti-slip multi-lobed concrete pads, special binding wires, steel bar positioning brackets and template positioning pins. The inner wall of the central hole of the anti-slip multi-lobed concrete pad is provided with a spiral groove, and the outer surface of the plum blossom petals is provided with an outer anti-slip structure. The anti-slip multi-petal concrete pad uses a six-petal plum blossom-shaped solid structure with an overall diameter of 70mm and a thickness of 30mm. The main material is C40 fine stone concrete (aggregate particle size 5-10mm, sand ratio 38%, water-cement ratio 0.42), and 0.5% (by mass) of 12mm long polypropylene fiber (tensile strength 650MPa) is added to ensure a compressive strength of 42MPa and a single block load capacity ≥600N. The center hole of the pad has a diameter of 11mm, and the inner wall is provided with a continuous spiral groove with a pitch of 4mm and a tooth depth of 1.8mm. The outer surface of the plum blossom petals is an arc-shaped corrugated anti-slip surface (wave height 2.5mm, wavelength 6mm) to meet the friction requirements of steel formwork.

[0024] The diameter of the special binding wire is set at 1.5mm, which can fit the 11mm diameter hole in the center of the pad, ensuring smooth wire insertion and no obvious loose gaps after insertion; the rebar positioning bracket is selected to fit the 25mm diameter rebar, with an inner diameter of 25mm, which can be tightly fitted on the outside of the rebar; the length of the template positioning pin is set at 30mm, and the sum of the pad thickness and the positioning pin length reaches a 60mm matching relationship, accurately matching the designed rebar protective layer thickness.

[0025] After the components are selected, quality inspections must be carried out in batches, with 10% of the components randomly selected from each batch for inspection. For the pads, a special gauge is used to inspect the spiral grooves on the inner wall of the center hole. If the groove tooth depth error exceeds ±0.2mm, the component is deemed scrap. At the same time, the corrugated structure on the outer surface of the plum blossom petals is checked to ensure there are no defects such as missing corners or breakage. For the special binding wire, its strength performance is verified through a tensile test. If the breaking strength is lower than 550 MPa, it is rejected. For the template positioning pins, the length is measured using a digital caliper with an accuracy of 0.01mm. If the length error exceeds ±1mm, the component must not be used. Through the above inspection process, the quality of all components is ensured to meet the construction requirements.

[0026] S2. Mark the installation position of the spacer block on the outside of the vertical reinforcing bar; This step uses a 5-meter steel tape measure with an accuracy of ±1mm, along with a marker and a level, to ensure the accuracy of the installation position markings. The spacing of the installation positions is: 500-800mm vertically and 300-500mm horizontally, with the spacing of corner rebar installation points increased to 300mm. Specifically, when marking the installation points of the spacers along the outside of the vertical rebars, the standard is a vertical spacing of 600mm and a horizontal spacing of 400mm. For the four vertical rebars at the column corners, considering their more concentrated stress in the structure and higher stability requirements during vibration, the spacing of the installation points is increased to 300mm.

[0027] During the marking process, each marking line must be calibrated segment by segment using a level to ensure that the horizontal deviation of the marking line does not exceed one degree, thus avoiding misalignment of the subsequent pad installation position due to tilted markings. This marking scheme effectively solves the problem of support failure during vibration caused by excessively large installation spacing (such as 1,000 mm) during construction. By optimizing the spacing design, the support density of the pads for the reinforcing bars is increased, laying the foundation for the stability of the subsequent positioning structure.

[0028] S3. Pass the special binding wire through the center hole of the anti-slip multi-lobed concrete pad and tie it to the vertical steel bar so that the wire is embedded in the spiral groove of the center hole. First, perform the wire threading operation. Use a special wire threader made of 1 mm diameter steel wire. Insert the threader into one end of the center hole of the pad and out the other end. Then, tie one end of a special binding wire to the threader and slowly pull the threader to allow the wire to smoothly pass through the center hole along the threader's trajectory. During the operation, it is necessary to control the pulling force to avoid scratching the spiral groove on the inner wall of the center hole with excessive force, which would affect the subsequent engagement of the wire with the groove.

[0029] After threading the wire, proceed to the binding and securing stage. Place the spacer block on the outside of the vertical rebar, adjust the position of the spacer block to ensure that the spacer block is in close contact with the surface of the rebar; after wrapping the wire around the rebar twice, thread it back through the center hole, and manually tighten it until there is no loose wire, and check the tightening torque with a torque wrench to be ≥5N・m; Specifically, wrap one end of the wire around the rebar twice, with the first wrap close to the rebar surface and the second wrap pressing on top of the first. This double-wrap method distributes the tension, preventing excessive stress at a single point that could damage the rebar or wire. The other end of the wire is then threaded back through the center hole. First, tighten the wire by hand to ensure the spacer block shows no obvious signs of loosening. Then, using a digital torque wrench with an accuracy of ±0.1 N·m, clamp the end of the wire and slowly apply torque until it reaches 5.5 N·m. After the torque is achieved, double verification is required: gently shake the spacer block to observe for any displacement; simultaneously, closely inspect the engagement between the wire and the spiral groove on the inner wall of the center hole, ensuring the wire is fully embedded in the groove to a depth of at least 1.2 mm. This step solves the slippage problem caused by insufficient adhesion between the wire and the hole wall during construction, significantly improving the stability of the binding structure.

[0030] S4. Install steel bar positioning brackets on the vertical steel bars on the upper and lower sides of the anti-slip multi-lobed concrete pad to restrict the pad from sliding along the axial direction of the steel bars. The installation of the rebar positioning brackets follows the sequence of bottom-to-top and close-fitting positioning. First, install the lower bracket by attaching it to the vertical rebar through its opening. Slowly adjust the position of the bracket to ensure that the lower end face of the lower bracket is precisely aligned with the installation line marked in step S2. After alignment, use a level to calibrate the end face of the bracket to ensure that it remains horizontal. Next, place the already tied spacer on the rebar and gently adjust the spacer downwards to ensure that the lower end face of the spacer is tightly fitted with the upper end face of the lower bracket. After fitting, check for any gaps between them. Finally, install the upper bracket by attaching it to the rebar through the opening as well. Adjust the position of the upper bracket so that its lower end face is fitted with the upper end face of the spacer, and the gap at the fitting point does not exceed 0.2mm.

[0031] After installation, the clamping performance needs to be verified: Gently pull the upper and lower clamps by hand to check for any signs of looseness; at the same time, use a force gauge to test the axial resistance of the clamps to ensure the resistance is adequate. This ensures that the positioning bracket can effectively limit the sliding of the pad along the axial direction of the reinforcing bar, and prevents the pad from shifting up and down during the concrete pouring and vibration process.

[0032] S5. Attach template positioning pins to the outer anti-slip structure surface of the anti-slip multi-lobed concrete pad block, calibrate the distance between the positioning pins and the reinforcing bars, and ensure that the design protective layer thickness is met. First, prepare the base surface: lightly sand the outer corrugated surface of the pad with 80-grit sandpaper to remove surface dust and release agent residue, exposing the fresh concrete surface; then wipe the sanded surface with a lint-free cloth dampened with alcohol to remove dust, and let it dry for 5 minutes until the surface is dry.

[0033] After the base surface is prepared, proceed to the bonding and calibration stage: Apply epoxy resin AB glue (glue ratio 1:1) evenly to the bonding surface of the template positioning pin, and control the glue layer thickness to 0.2-0.3mm. Avoid generating air bubbles during the application process; attach the positioning pin to the outer corrugated surface of the pad, and use a right-angle ruler to calibrate the perpendicularity of the positioning pin axis to the radial direction of the pad, ensuring that the deviation is ≤1°. After calibration, apply 50N of pressure by hand and hold for 30 seconds to initially fix the positioning pin to the pad. Then let it stand for 2 hours to allow the glue to fully cure.

[0034] After curing, thickness calibration is performed: Using a digital caliper with an accuracy of 0.01mm, measure the distance between the end of the locating pin furthest from the pad and the surface of the rebar, ensuring this distance is 60mm (i.e., the designed rebar protective layer thickness). If the deviation exceeds ±1mm, the locating pin position needs to be readjusted and the curing calibration repeated. This step effectively controls the protective layer thickness deviation, reducing the deviation range from ±5mm in traditional construction to ±1mm, significantly improving thickness control accuracy.

[0035] S6. Install the template so that the inner side of the template fits the outer anti-slip structure of the pad block.

[0036] Specifically, wipe the inside of the formwork with a cotton cloth to remove oil and rust. Apply a water-based release agent evenly to the inside of the steel formwork, controlling the thickness to 0.1mm. Use a roller to apply the agent horizontally, ensuring no oil accumulation or missed areas, and ensuring a uniform coating. After application, allow it to dry for 30 minutes until the release agent forms a transparent film on the formwork surface (not sticky to the touch), preventing subsequent concrete from adhering to the formwork. If using wooden formwork, an additional 0.1mm thick polyethylene waterproof membrane must be laid on the inside of the formwork (secured at the edges with double-sided tape), and then the release agent should be applied following the same steps to prevent the wooden formwork from absorbing water and deforming, which could lead to positioning deviations.

[0037] The template installation adopts a bottom-up, layered installation method. To ensure the fitting accuracy between the template and the pad during installation, the height of each template layer is controlled to not exceed 500mm. When installing the first layer, the 1m high template is first divided into two layers (500mm each). The lower 500mm high template is placed close to the outside of the column, and the template is slowly pushed towards the column with both hands until the inside of the template is tightly fitted with the end of the template positioning pin (number 4) away from the anti-slip multi-lobed concrete pad. At this time, the inside of the template and the corrugated surface of the outer layer of the pad also make initial contact, avoiding the positioning pin from shifting or the pad from moving due to pushing too fast.

[0038] After the template is initially attached, a fit check is performed: a feeler gauge with an accuracy of 0.02mm is used to measure the gap between the template and the spacer at different contact points (one test point is selected every 100mm). The gap at all test points is controlled within 0.3mm, and the gap at some test points is 0.15mm and 0.28mm, which fully meets the standard of complete tight fit. This ensures that the gap will not cause grout leakage or spacer displacement during subsequent concrete pouring.

[0039] After the fit meets the standard, fix the template: Use M12 tie bolts, make bolt holes on the template at 400mm intervals and insert bolts, use a torque wrench to slowly tighten the bolts, and control the tightening torque at 30N・m to avoid deformation of the template due to excessive torque, which would affect the accuracy of the protective layer thickness, and also to prevent the template from being not firmly fixed due to insufficient torque.

[0040] S7. Pouring monitoring and post-pouring verification: Control the vibration operation during concrete pouring, check the thickness of the steel reinforcement protective layer after the formwork is removed, and repair any deviations; The vibration is performed using a vibrator, with the distance between the vibrator and the pad block ≥100mm, the vibration frequency 200-300Hz, and the vibration time at a single location 10-15s, in order to solve the problem of pad block displacement caused directly by the vibration impact force.

[0041] Specifically, before pouring concrete, confirm the concrete parameters and pouring process: use C35 ready-mixed concrete (slump controlled at 180mm±20mm, initial setting time ≥6 hours) to avoid pouring difficulties due to poor concrete fluidity or displacement of the formwork blocks due to excessive strength. Use a layered pouring method, strictly controlling the height of each layer to within 500mm, maintaining a pouring speed of 0.3m³ / h, and proceeding uniformly from one side of the column to the other to avoid excessive pressure on one side, which could compress the formwork and formwork blocks. Vibration is the core monitoring step; use a Φ50mm immersion vibrator. Before vibration, measure the distance between the vibrator and the formwork blocks to ensure that the distance between the vibrator insertion point and the block is not less than 120mm each time. The vibration frequency was set to 250Hz (within the 200-300Hz range), and the vibration time at a single point was controlled to 13 seconds (within the 10-15 second range). Vibration was stopped when no more continuous bubbles emerged from the concrete surface, the surface became smooth and no longer settled. This prevented over-vibration from causing concrete segregation or under-vibration from leaving a honeycomb-like surface, and also prevented the vibration impact force from directly acting on the spacers and causing displacement. Two dedicated personnel were assigned to monitor the entire process during pouring. A 20mm diameter observation hole was reserved every 500mm on the outside of the formwork. The monitoring personnel used a flashlight and a small endoscope through the observation holes to check the status of the spacers in real time, paying particular attention to whether the spacers were sliding along the formwork, whether the positioning pins had fallen off, and whether the retaining brackets were loose. The entire monitoring process was recorded. In this embodiment, no spacer displacement or component detachment occurred.

[0042] After the concrete pouring is completed, the post-treatment stage begins: First, curing is carried out by covering the column surface with geotextile and sprinkling water to maintain moisture. The curing time is no less than 7 days, during which the ambient temperature is kept above 5℃ to avoid low temperatures affecting the concrete strength development. The formwork can only be removed after the concrete cube compressive strength reaches 75% of the design strength (actually measured at 26.2MPa, while the design strength of C35 concrete is 35MPa). When removing the formwork, the principle of "non-load-bearing first, then load-bearing, top to bottom" must be followed. Use a pry bar to gently pry from the formwork joints, avoiding excessive force that could damage the pads or positioning pins, thus preventing damage to the formed concrete surface. At the same time, protect the positioning components for later recycling (such as the rebar positioning brackets, which can be disassembled and reused).

[0043] After the formwork is removed, the thickness of the concrete cover is tested: a concrete cover thickness measuring instrument conforming to GB / T50344 standard (accuracy ±1mm) is used. The instrument is calibrated before testing (calibration error ≤0.5mm using standard test blocks). Ten testing points are randomly selected for each column across three height segments (top, middle, and bottom) (at least three points per height segment, with coverage at corners and the middle). During testing, the instrument probe is placed close to the concrete surface, avoiding rebar joints and embedded parts to ensure accurate data. In this example, 50 points were tested on 5 frame columns. The results showed 49 qualified points, a pass rate of 98%, with an average cover thickness of 59.8mm, and thickness deviations concentrated within ±0.8mm. Only one testing point had a thickness of 65.3mm (exceeding the ±5mm deviation standard), requiring repair.

[0044] During the repair, first use an electric drill (with a Φ6mm drill bit) to drill four anchor holes (50mm apart) around the area exceeding the tolerance. Use compressed air to blow away dust and debris from the holes, then apply a concrete interface agent (0.1mm thick). After the interface agent is surface dry, fill it with C40 epoxy resin mortar (mixture ratio: epoxy resin: hardener: quartz sand = 1:0.2:3), and compact and smooth it with a trowel to ensure a tight bond between the mortar and the original concrete. After the repair is completed, cover it with plastic film for curing for 3 days. The thickness at this point is then checked again and found to be 60.2mm, with the deviation reduced to ±0.2mm, meeting the design requirements and completely solving the problem of later thickness deviation affecting the structural durability.

[0045] In summary, the present invention has the following advantages: 1. By setting a spiral groove in the center hole of the pad block and designing an anti-slip structure for different scenarios on the outer layer, the slippage rate of the wire is reduced and the displacement rate of the pad block after vibration is reduced, which can greatly improve the positioning stability. 2. By precisely matching the design thickness with the length of the template positioning pins and calibrating the spacing with a digital caliper during installation, the thickness deviation is reduced to ±1-2mm, improving the pass rate of the protective layer and reducing the amount of subsequent repair work. 3. By designing multi-specification pads and multi-model rebar positioning brackets, combined with an outer layer of scene-specific anti-slip structure, it covers mainstream rebar diameters and both steel and wood templates, improving adaptability to various scenarios and reducing construction costs. 4. By clarifying standardized construction parameters and setting key step verification nodes, the average daily construction efficiency per person has been improved, and the difference in construction quality between different work teams has been reduced to less than 3%.

[0046] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for locating the concrete cover of reinforcing bars in vertical structures such as walls and columns, characterized in that, include: S1. Based on the diameter of the vertical steel bars and the designed thickness of the steel bar protective layer, select suitable anti-slip multi-lobed concrete pads, special binding wires, steel bar positioning brackets and template positioning pins. The inner wall of the central hole of the anti-slip multi-lobed concrete pad is provided with a spiral groove, and the outer surface of the plum blossom petals is provided with an outer anti-slip structure. S2. Mark the installation position of the spacer block on the outside of the vertical reinforcing bar; S3. Pass the special binding wire through the center hole of the anti-slip multi-lobed concrete pad and tie it to the vertical steel bar so that the wire is embedded in the spiral groove of the center hole. S4. Install steel bar positioning brackets on the vertical steel bars on the upper and lower sides of the anti-slip multi-lobed concrete pad to restrict the pad from sliding along the axial direction of the steel bars. S5. Attach template positioning pins to the outer anti-slip structure surface of the anti-slip multi-lobed concrete pad block, calibrate the distance between the positioning pins and the reinforcing bars, and ensure that the design protective layer thickness is met. S6. Install the template so that the inner side of the template fits the outer anti-slip structure of the pad block.

2. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, Also includes: S7. Pouring monitoring and post-pouring verification: Control the vibration operation during concrete pouring, check the thickness of the steel reinforcement protective layer after the formwork is removed, and repair any deviations. The vibration is performed using a vibrating rod, with a distance of ≥100mm between the vibrating rod and the pad, a vibration frequency of 200-300Hz, and a single-point vibration time of 10-15s, in order to solve the problem of pad displacement caused directly by the vibration impact force.

3. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 2, characterized in that, The thickness of the concrete cover for reinforcing bars is tested using a concrete cover thickness measuring instrument. The standard is to randomly test 10 points for each column, and the column is considered qualified when the pass rate is ≥95%. If the deviation of a single test point exceeds ±5mm, use epoxy resin mortar with a strength of C35 or higher to repair it, so as to solve the problem of the thickness deviation affecting the durability of the structure in the later stage.

4. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, The spacing of the installation positions is as follows: vertical spacing of 500-800mm, horizontal spacing of 300-500mm, and the spacing of the corner steel reinforcement installation points is increased to 300mm.

5. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, The spiral groove that allows the wire to be embedded in the central hole specifically includes: After wrapping the wire around the rebar twice, thread it back through the center hole and manually tighten it until there is no looseness left. The tightening torque should be ≥5 N·m when checked with a torque wrench.

6. The method for locating the protective layer of reinforcing bars in vertical wall and column structures according to claim 1, characterized in that, The step S4 is followed by a card slot installation verification step: Gently pull the rebar positioning bracket by hand to check for looseness; then use a force gauge to test the axial resistance of the bracket to ensure that the resistance is ≥100N. If the resistance does not meet the standard, readjust the position of the bracket until it meets the standard.

7. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, The step S6 is preceded by template preprocessing: If it is steel formwork, apply water-based release agent evenly to the inside; if it is wooden formwork, first lay a waterproof membrane on the inside of the formwork and then apply the release agent, let it dry for 30 minutes before installation, in order to solve the problem of formwork sticking to concrete or positioning deviation caused by water absorption and deformation of wooden formwork.

8. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, In step S6, the template inner side is bonded to the outer anti-slip structure of the pad block. The installation is carried out in layers from bottom to top. After each layer of template contacts the pad block, the installation is paused and the fit is checked until it is completely sealed before continuing.

9. The method for locating the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, The step S1 is followed by a component quality inspection step: Inspect the spiral grooves and outer anti-slip structure of the anti-slip multi-lobed concrete pad; test the breaking strength of the special binding wire; measure the length of the template positioning pins with a digital caliper and reject unqualified components.

10. The method for positioning the concrete cover of steel bars in vertical wall and column structures according to claim 1, characterized in that, The distance between the calibration positioning pin and the reinforcing bar specifically includes: Using a digital caliper with an accuracy of 0.01mm, measure the distance between the end of the locating pin furthest from the pad and the surface of the vertical reinforcing bar. If the distance deviation exceeds ±1mm, remove the locating pin, clean the surface of the pad again, and then re-align it.

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