Millimeter-level reinforced concrete reinforcement protective layer positioning device and method

Abstract

The present invention relates to a millimeter-level reinforced concrete steel bar protective layer positioning device and method. The device includes a cross clamp fixed end, a threaded pressure rod, a cross clamp, and a fixed end provided on the cross clamp fixed end. The cross clamp is connected to the fixed end of the steel bar positioning part through a connecting rod. The threaded pressure rod is sequentially installed with a fastening nut, a spring washer, a rotating double-layer sleeve, and an insert. The device is set at the intersection of the steel bars through the fixed end, and is fixed to the steel bar skeleton together with the cross clamp by tying iron wire or welding. The rotating sleeve accurately determines the thickness of the protective layer. After tightening the fastening nut, a steel bar protective layer positioning device is formed, and the device is installed on the steel bar skeleton during the forming process. It has the advantages of simple structure, economy, easy installation, positioning accuracy reaching the millimeter level, stability, concrete can completely wrap the components, improve construction efficiency and quality, ensure design mechanical indicators, and not reduce the structural cross-sectional area.

Description

Technical Field

[0001] The present invention relates to the field of civil engineering structure construction, and in particular to a device and method for positioning a millimeter-level reinforced concrete steel bar protective layer. Background Art

[0002] Reinforced concrete and prestressed concrete are widely used in all civil engineering construction fields. According to structural design principles and concrete material requirements, both steel and prestressed steel require a concrete cover within the concrete. This ensures a certain thickness of concrete from the outermost edge of the steel or prestressed steel to the concrete surface. This ensures that the steel and concrete form a cohesive structure, provides a certain bond strength, and meets the requirements of mechanical calculations. This also prevents surface temperature cracking of the concrete, which can lead to corrosion and rusting of the steel due to atmospheric oxygen and water, and thus affect the durability of the concrete structure. In the event of a fire, a sufficient concrete cover thickness protects the steel within the structure from thermal strength loss, which could lead to collapse. The positioning and setting of the concrete cover thickness for both steel and prestressed steel is crucial to the mechanical performance, quality, durability, and safety of reinforced and prestressed concrete structures. Therefore, the highway project handover and completion acceptance method issued by the Ministry of Transport clearly stipulates that the thickness of the concrete structure protective layer needs to be tested. The Ministry of Housing and Urban-Rural Development stipulates that the use of simple on-site production of steel bar protective layer pads (steel bar protective layer pads are produced on-site by mixing mortar, cutting and other processes) will be prohibited starting from September 15, 2022.

[0003] Currently, the protective layer pads commonly used for steel bars and prestressed reinforced concrete components include plastic, concrete blocks or concrete sleeves, and specially manufactured steel components. Plastic pads are easily deformed during formwork installation and correction, affecting positioning accuracy and thickness. In particular, the temperature deformation rate of plastic and concrete differs significantly. When the external temperature fluctuates during use, the thermal expansion and contraction of the plastic pads can cause cracks and voids in the surrounding concrete. Oxygen and moisture in the air can corrode the steel bars, affecting the durability of the structure. Concrete blocks or concrete sleeves have problems with inaccurate thickness positioning and can cause displacement, overturning, or voiding when correcting the steel skeleton. In particular, the different creep of concrete formed at different times can cause cracks at the interface between new and old concrete, also affecting structural durability. Specially manufactured steel components require spray-coating for rust prevention. They can also cause displacement, overturning, or voiding when correcting the steel skeleton. They also have poor adhesion to concrete, resulting in cracks on the contact surface. In the event of a fire, heat transfer is rapid, which can cause rapid structural collapse. Furthermore, the cost is high.

[0004] The existing disc-type plastic and disc-type concrete locators are generally worn on stirrups or distribution bars, or outer steel bars, and cannot be used at the nodes between main bars and stirrups. During the clamping and extrusion process of the steel skeleton and formwork, the stirrups have a small cross-section, poor bending resistance, and are easily deformed, which will cause the concrete cover to become smaller. Concrete pads or other pads will have slight displacements during the correction of the steel skeleton or formwork, causing the pads to shift or fail, affecting the positioning effect of the protective layer. There are also some theoretical and technical explorations of steel bar protective layer locators. In addition to the complex structure and the presence of voids in the locator itself, the entire locator or related components cannot be fully wrapped by concrete, reducing the effective cross-sectional area of ​​the structure. They cannot be used at steel bar nodes, and slight displacements of the steel skeleton and formwork will cause them to be crooked and fail. In addition, the cost is high, the structure is complex, and there are many shortcomings, making them difficult to apply in practice.

[0005] During the construction of reinforced concrete foundations for highway, municipal, and railway projects, a foundation cushion is often considered for ease of operation and to ensure a correct underlying reinforcement cover. Often, the foundation reinforcement is placed directly on the cushion concrete. However, under normal circumstances, the concrete grade of the cushion is relatively low, and the foundation's geometric dimensions do not include the cushion concrete thickness. Therefore, even with a cushion, a precise reinforcement cover is still required for the underlying reinforcement of reinforced concrete foundations. For bored piles with mud walls, the hole walls are irregular due to geological variations beneath the hole. Current bored pile foundations utilize a circular protective layer positioning device with "〔"-shaped steel bars welded to the main reinforcement cage along the perimeter to guide the cage into the hole. However, due to potential hole misalignment, correcting the cage will cause the "〔"-shaped protective layer positioning bars to abut one side of the hole wall, or even partially penetrate the hole wall, making it difficult for the protective layer positioning device to ensure the concrete cover thickness. Furthermore, once the "〔"-shaped protective layer positioning bars rust, they can cause corrosion of the main reinforcement, impacting the durability and bearing capacity of the project. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a millimeter-level reinforced concrete steel bar protective layer positioning device, which has the effects of simple structure, economy, easy installation, positioning accuracy reaching millimeter level, stability, concrete can completely wrap the components, improve construction efficiency and quality, ensure design mechanical indicators, and not reduce the structural cross-sectional area.

[0007] The technical solutions of the present invention are as follows:

[0008] A millimeter-level reinforced concrete steel bar protective layer positioning device comprises a cross clamp fixing end, a fastening nut, a spring washer, and a rotating double-layer sleeve;

[0009] The cross clamp fixed end includes a fixed end, a clamp, a connecting rod connecting the fixed end and the clamp, and a threaded pressure rod on the fixed end;

[0010] The rotating double-layer sleeve includes a tongue, an internal threaded sleeve and a separating stiffening plate;

[0011] Small holes are provided in the radial direction on the internal threaded sleeve, and the concrete slurry fills the space inside the internal threaded sleeve through the small holes;

[0012] The threaded pressure rod on the fixed end of the cross clamp is connected to the fastening nut through threaded rotation. The spring washer is placed between the fastening nut on the threaded pressure rod and the rotating double-layer sleeve. The rotating double-layer sleeve is connected to the threaded pressure rod on the fixed end of the cross clamp through threaded rotation.

[0013] Furthermore, it also includes an insert block, and concrete slurry enters to fill the gap between the insert block and the separating stiffening plate; the tongue of the rotating double-layer sleeve is used to fix the inserted insert block through friction; the rotating double-layer sleeve has no less than 4 tongues, and the cumulative length of the width of each piece is no less than half the circumference length.

[0014] Furthermore, small holes distributed in a plum blossom shape are provided in the radial direction on the internal threaded sleeve.

[0015] Furthermore, the partition stiffening plate is provided with distributed plum blossom-shaped small holes to allow concrete slurry to enter the gap between the filling plug and the partition stiffening plate.

[0016] Furthermore, the fixed end of the cross clamp is arranged at the intersection of the outermost stirrups or distribution bars and the second outermost steel bars or steel of the steel frame structure, and the arc-shaped positioning groove of the fixed end is clamped at the intersection of the outermost stirrups or distribution bars and the second outermost steel bars or steel. The cross clamp is clamped on the outermost stirrups or distribution bars and the second outermost steel bars or steel through the clamp, and is tied or welded to the steel frame.

[0017] Furthermore, the angle between the cross connecting rod and the threaded compression rod is 90 degrees, and the clamp connecting rod of the second outer layer of steel bars or steel forms a certain angle with the fixed end, and the angle between the cross connecting rod and the threaded compression rod is greater than 90 degrees.

[0018] The present invention also relates to a construction method of a millimeter-level reinforced concrete steel bar protective layer positioning device, comprising the following steps:

[0019] Step (1) calculating the number of the devices required on the bottom surface based on the weight of the steel bars and the steel forming structure skeleton, the distribution of the steel bars or stirrups on the bottom surface, and the supporting weight that the devices can bear, and planning and arranging the devices on the bottom surface and the side surfaces;

[0020] Step (2) accurately lay out the positions of the distribution bars or stirrups on the bottom mold or pedestal and mark them, and clearly mark the points where the device is planned and arranged according to the above step (1);

[0021] Step (3) screw the fastening nut into the threaded pressure rod at the fixed end of the cross clamp, put on the spring washer, insert the plug into the rotating double-layer sleeve, rotate the internal threaded sleeve of the rotating double-layer sleeve into the threaded pressure rod at the fixed end of the cross clamp to the position required for the insulation layer thickness, and tighten the fastening nut to position the rotating double-layer sleeve;

[0022] Step (4) placing the assembled device according to the cross position of the steel bars marked on the bottom mold, and installing the distribution steel bars or stirrups, the secondary outer steel bars or steel materials on the arc-shaped positioning grooves at the fixed ends thereof, and at the same time using the steel bar binding wire to bind and connect with the steel bars at the clamps, and forming other steel bars according to the designed steel bar skeleton structure;

[0023] Step (5) After the steel frame is formed, check whether the thickness of the bottom mold steel bar protective layer is accurate. If there is a difference, loosen the fastening nut, rotate the double-layer sleeve to adjust it, and then tighten the fastening nut again;

[0024] Step (6) installing the device at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end is clamped on the outermost steel bar, and the clamp is tied to the outermost and second outermost steel bars with binding wire;

[0025] Step (7) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut, rotate the double-layer sleeve to adjust, and then tighten the fastening nut again;

[0026] Step (8) pouring concrete in layers and in sequence, and curing it, and removing the formwork after reaching the specified demoulding time and strength.

[0027] The present invention also relates to a construction method of a millimeter-level reinforced concrete steel bar protective layer positioning device, comprising the following steps:

[0028] Step (1) The geometric dimensions and elevation of the pre-tensioned pedestal are accurately positioned, and the elevation of the pedestal top surface and the distance between the steel strands or steel wires after tensioning are in accordance with the requirements of the design drawings;

[0029] Step (2) accurately lay out the bottom distribution reinforcement position on the pedestal and mark it, and at the same time calculate the weight of the steel strand or steel wire after the steel skeleton is loaded. The principle when considering the installation quantity of the device is that the steel strand or steel wire does not bear the load transmitted by the steel skeleton, ensure that the tension of the steel strand or steel wire is accurate, and plan the point of the device and mark it clearly;

[0030] Step (3) pre-tensioning the steel strands or steel wires, wherein the pre-tensioning stress does not exceed 5 to 8% of the design tensioning force, to ensure that the steel strands or steel wires are taut and perform steel skeleton forming operations;

[0031] Step (4) screw the fastening nut into the threaded pressure rod at the fixed end of the cross clamp, put on the spring washer, insert the plug into the tongue of the rotating double-layer sleeve, rotate the internal threaded sleeve of the rotating double-layer sleeve into the threaded pressure rod at the fixed end of the cross clamp to the position required for the thickness of the insulation layer, and tighten the fastening nut to position the rotating double-layer sleeve;

[0032] Step (5) preliminarily installs the assembled device at the position of the bottom distribution reinforcement, so that the arc-shaped positioning groove of the fixed end is clamped with the distribution reinforcement, the clamp on the cross connecting rod along the arc-shaped positioning groove is tied with the distribution reinforcement, and then the block is inserted through the gap between the steel strand or steel wire and the pedestal, the plug contacts the bottom surface of the pedestal, the clamp on the cross connecting rod perpendicular to the arc-shaped positioning groove is clamped with the steel strand or steel wire, and is fixed with iron wire; at the same time, the nodes of the distribution reinforcement and the steel strand or steel wire are tied to keep the distribution reinforcement and the steel strand or steel wire in close contact, and other reinforcements are formed according to the designed reinforcement skeleton structure;

[0033] Step (6) After the steel skeleton is formed, check whether the steel geometry and steel type of the steel skeleton are correct, tension the steel strands or wires to the design stress, and check whether the thickness of the steel protection layer of the pedestal distribution is accurate. If there is a difference, loosen the fastening nut, rotate the double-layer sleeve to adjust, and then tighten the fastening nut again to accurately position it at the millimeter level;

[0034] Step (7) installing the device at the intersection of the stirrups and the second outermost steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end is clamped on the outermost steel bar, and the clamp is tied to the outermost and second outermost steel bars with binding wire;

[0035] Step (8) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut, rotate the double-layer sleeve to adjust, and then tighten the fastening nut again;

[0036] Step (9) Concrete is poured layer by layer and in sequence, and cured. After the specified demoulding time and strength are reached, the formwork is removed and the tensile stress is released.

[0037] The present invention also relates to a construction method of a millimeter-level reinforced concrete steel bar protective layer positioning device, comprising the following steps:

[0038] Step (1) According to the steel structure design drawing of the cast-in-place reinforced concrete structure, the cutting length of each steel bar is calculated based on the designed position of the stress-bearing steel bars, and the steel bars are manufactured and formed according to the type specified in the design;

[0039] Step (2) The support formwork is installed and pre-pressed to adjust the elevation. The strength, rigidity and flatness of the bottom formwork and side formwork meet the design requirements.

[0040] Step (3) calculating the number of the devices required on the bottom surface based on the weight of the steel bar forming structure skeleton and embedded parts, the distribution of steel bars or stirrups on the bottom surface, and the supporting weight that can be borne by using a single device, and planning and arranging the devices on the bottom surface and side surfaces;

[0041] Step (4) accurately lay out the distribution reinforcement or stirrup positions on the bottom form and mark them, and at the same time plan and arrange the points of the device according to the above step (3) and clearly mark them on the template;

[0042] Step (5) screw the fastening nut of the device into the threaded pressure rod at the fixed end of the cross clamp, put on the spring washer, insert the plug into the rotating double-layer sleeve, rotate the internal threaded sleeve of the rotating double-layer sleeve into the threaded pressure rod at the fixed end of the cross clamp to the position required for the thickness of the insulation layer, and tighten the fastening nut to position the rotating double-layer sleeve;

[0043] Step (6) placing the assembled device according to the cross position of the steel bars marked on the bottom mold, and installing the distribution steel bars or stirrups, the second outer layer steel bars or steel materials on the arc-shaped positioning grooves at the fixed ends thereof, and at the same time using the binding wire for binding the steel bars to bind and connect with the steel bars at the clamps, and forming other steel bars according to the designed steel bar skeleton structure. When the steel bars are divided into upper and lower layer structures, the spacing between the upper and lower layers is accurately fixed according to conventional methods;

[0044] Step (7) After the steel frame is formed, check whether the thickness of the bottom mold steel bar protective layer is accurate. If there is a difference, loosen the fastening nut, rotate the double-layer sleeve to adjust it, and then tighten the fastening nut again;

[0045] Step (8) installing the device at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end is clamped on the outermost steel bar, and the clamp is tied to the outermost and second outermost steel bars with binding wire;

[0046] Step (9) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut, rotate the double-layer sleeve to adjust, and then tighten the fastening nut again;

[0047] Step (10) Concrete is poured layer by layer and in sequence, and cured. The support and formwork are removed after the specified demoulding time and strength are reached.

[0048] The present invention also relates to a construction method of a millimeter-level reinforced concrete steel bar protective layer positioning device, comprising the following steps:

[0049] Step (1) According to the steel structure design drawing of the cast-in-place reinforced concrete bored pile structure, the cutting length of each steel bar is calculated based on the designed position of the stress-bearing steel bar, and the steel bar is manufactured and formed according to the type specified in the design;

[0050] Step (2) The bored pile must be accurately laid out before drilling and checked for accuracy; the drilling process should be slow and even, the wall slurry consistency should be maintained, and the deviation of the hole should be checked at any time to make effective corrections;

[0051] Step (3) planning and arranging the minimum number and arc spacing required for one circle of the device according to the diameter of the bored pile reinforcement cage forming structure skeleton;

[0052] Step (4) arranging the device on the bored pile reinforcement cage at intervals of 3 to 6 meters, and marking the bored pile reinforcement cage;

[0053] Step (5) screw the fastening nut of the device into the threaded pressure rod at the fixed end of the cross clamp, put on the spring washer, insert the plug into the rotating double-layer sleeve, rotate the internal threaded sleeve of the rotating double-layer sleeve into the threaded pressure rod at the fixed end of the cross clamp to the position required for the thickness of the insulation layer, and tighten the fastening nut to position the rotating double-layer sleeve;

[0054] Step (6) Install the assembled device according to the marked position of the above step (4), clamp the arc-shaped positioning groove of the fixed end at the intersection of the stirrup and the main reinforcement, spot weld the clamp on the cross connecting rod along the arc-shaped positioning groove to the stirrup, clamp the clamp on the cross connecting rod perpendicular to the arc-shaped positioning groove to the main reinforcement and then spot weld, and check the stability of the device plug;

[0055] Step (7) After the hole is drilled, the hole position, verticality and hole diameter are inspected. If the deviation of the hole position, verticality and hole diameter exceeds the specified value, the hole position, verticality and hole diameter should be corrected and then the hole should be cleaned.

[0056] Step (8) Use a crane or other lifting equipment to vertically lift the steel cage, align the center of the steel cage with the center of the drill hole, slowly and evenly insert the steel cage into the hole, and fix the steel cage after reaching the height of the steel cage; when the steel cage needs to be extended, it should be welded and extended while it is vertically lifted;

[0057] Step (9) lowers the conduit and performs underwater concrete pouring.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The present invention is a millimeter-level precision positioning device, because the steel bar protective layer cannot be too thick. If it is too thick, the geometric dimensions of the concrete structure will be increased, which is not economical and will cause excessive cracks in the concrete protective layer in the tension zone. If the protective layer is too thin, the concrete cannot guarantee the grip of the steel, so that the concrete and steel cannot form an integrated structure, and the durability of the structure is affected. Under normal conditions, the thickness of the steel bar protective layer is between 15mm and 55mm. The relevant national construction acceptance specifications generally allow construction deviations of plus or minus 3mm, plus or minus 5mm, plus or minus 10mm, or a value between plus or minus 3mm and 10mm. If the accuracy of the steel bar protective layer positioning device cannot be guaranteed to the millimeter level, it will not meet the requirements of the specification, indicating that the technology does not meet the current industry regulations and the technology is not feasible.

[0060] The existing steel bar protection pads cannot be effectively connected and fixed to the steel bars. When the steel bar skeleton is corrected or moved, it is difficult to ensure that the relative position of the steel bar and the protective layer pad remains unchanged, which affects the protective layer effect. When the pads are used vertically or laterally, they cannot be effectively connected and docked with the steel bars or formwork to ensure the stable installation of the pads. Plastic rings can only be used instead. Plastic rings and concrete rings cannot be installed at the intersection of the steel bars (they can only be installed close to them), and their positions are not fixed, resulting in poor positioning effect. The material properties of the pads are different from those of concrete and steel, and the positioning accuracy is not in the millimeter range. The present invention addresses the above problems from the following aspects: First, to ensure that the device of the present invention can be installed at the "cross" intersection of the steel bars and prevent displacement, a groove with a certain curvature is provided at the contact point between the fixed end and the steel bar. The fixed end is connected to a "cross" connecting rod. The end of the "cross" connecting rod is provided with a clamp. The clamp is clamped on the outermost and second outermost layers of the cross-intersecting steel bars, and is effectively connected to the steel bar skeleton by binding wire, which can also be spot welded. Secondly, in order to ensure the millimeter-level accuracy of the protective layer positioning device, combined with the changing requirements and versatility of the protective layer thickness under different environments, a threaded pressure rod is provided on the fixed end, and the threaded pressure rod is connected to the rotating double-layer sleeve by a threaded rotation. The total length of the device of the present invention is adjusted by rotating the position of the double-layer sleeve on the threaded pressure rod to achieve different protective layer thicknesses and millimeter-level positioning accuracy, and the rotating double-layer sleeve is fixed in the exact position on the threaded pressure rod with a spring washer and a fastening nut.

[0061] Taking into account the cost of the device of the present invention and the possible spot welding connection with the steel skeleton, the materials of the fixed end and the threaded pressure rod, the "cross" connecting rod, the clamp, the internal threaded sleeve, the spring washer and the fastening nut are mainly steel, so it is considered to use an insert to separate the steel from the outside world. The material of the insert can be consistent with the concrete aggregate or a material that will not rust or age and has a temperature expansion rate consistent with that of concrete.

[0062] In order to ensure that the device of the present invention is fully integrated with the concrete to form an integral structure, openings or holes are formed at various locations of the internal threaded sleeve.

[0063] The device of the present invention can adjust the size of corresponding parts according to the pressure of the steel frame and a certain amount of concrete placed at the bottom, or increase the number of arrangements of the device of the present invention.

[0064] The device of the present invention takes both technical creativity and economic efficiency into consideration, so as to facilitate its popularization and use in reinforced concrete and prestressed reinforced concrete in the civil engineering industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a structural schematic diagram of the positioning device for the reinforced concrete protective layer of the present invention;

[0066] Figure 2 Schematic diagram of the connection of the reinforcement concrete protective layer positioning device of the present invention at the reinforcement node;

[0067] Figure 3 It is a schematic diagram of the structure of the rotating double-layer sleeve and the insert block of the reinforced concrete protective layer positioning device of the present invention;

[0068] Figure 4 It is a schematic diagram of the AA section of the rotating double-layer sleeve;

[0069] Figure 5 It is a schematic diagram of the cross section of the rotating double-layer sleeve BB;

[0070] Figure 6 It is a schematic diagram of the CC section of the rotating double-layer sleeve;

[0071] Figure 7 It is a schematic diagram of the DD section of the plug;

[0072] Figure 8 This is a schematic diagram of the EE section of the clamp;

[0073] In the figure: 1-threaded compression rod, 2-fixed end, 3-cross connecting rod, 4-clamp, 5-second outer layer of steel bars or steel, 6-outermost layer of stirrups or distribution bars, 7-insert block, 8-tongue, 9-inner threaded sleeve, 10-partitioning stiffener, 11-rotating double-layer sleeve, 12-spring washer, 13-fastening nut, 14-small hole on the inner threaded sleeve, 15-small hole on the partitioning stiffener. DETAILED DESCRIPTION

[0074] 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. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0075] Unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meanings understood by a person of ordinary skill in the art. The terms "first," "second," and similar terms used in this embodiment do not indicate any order, quantity, or importance, but are simply used to distinguish different components. The terms "include" or "comprise," and similar terms, mean that the element or object preceding the term includes the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms "mounted," "connected," "coupled," and "connected" should be interpreted broadly. For example, they can mean fixed, removable, or integral; they can mean direct, indirect, or internally connected through an intermediary; and they can mean internal communication between two components. The terms "upper," "lower," "left," "right," "horizontal," and "vertical" are used only with respect to the orientation of components in the drawings. These directional terms are relative concepts and are used for description and clarification relative to the actual position of the components in the drawings. They may change accordingly depending on the orientation of the components in the drawings. Example 1

[0076] like Figure 1 As shown, the millimeter-level reinforced concrete reinforcement cover positioning device of this embodiment includes a threaded compression rod 1, a cross connecting rod 3, a clamp 4, a fixed end 2, a fastening nut 13, a spring washer 12, a rotating double-layer sleeve 11, and an insert 7. The threaded compression rod 1 on the fixed end of the cross clamp is connected to the fastening nut 13 via a threaded rotation. The spring washer 12 is placed between the fastening nut 13 on the threaded compression rod 1 and the rotating double-layer sleeve 11. The tongue 8 of the rotating double-layer sleeve 11 is used to secure the inserted insert 7 through friction.

[0077] The cross clamp fixed end is composed of a fixed end 2, a clamp 4, a cross connecting rod 3 connecting the fixed end 2 and the clamp 4, and a threaded pressure rod 1 on the fixed end 2, and is made as a whole.

[0078] The rotating double-layer sleeve 11 comprises a tongue piece 8, an internally threaded sleeve 9, and a separating stiffening plate 10. The tongue piece 8, the internally threaded sleeve 9, and the separating stiffening plate 10 are made as a whole.

[0079] Small holes distributed in a plum blossom shape are provided radially on the internal threaded sleeve 9, allowing concrete slurry to enter the filling space inside the internal threaded sleeve through the small holes; small holes distributed in a plum blossom shape are provided on the separation stiffening plate 10, allowing concrete slurry to enter the gap between the filling plug 7 and the separation stiffening plate 10.

[0080] The fixed end of the cross clamp is set at the intersection of the outermost stirrups or distribution bars 6 and the second outermost steel bars or steel 5 of the steel skeleton structure. The arc-shaped positioning groove of the fixed end 2 is clamped at the intersection of the outermost stirrups or distribution bars 6 and the second outermost steel bars or steel 5. The cross clamp is clamped on the outermost stirrups or distribution bars 6 and the second outermost steel bars or steel 5 through the clamp 4 respectively. The cross connecting rod 3 is used to connect the clamp 4 and the fixed end 2 into a whole to ensure that the fixed end 2 will not move or skew.

[0081] The angle between the cross-connecting rods 3 is 90°, and this angle can be adjusted based on the angle between the outermost and second-outer layers of the steel or steel in the steel skeleton structure. The curvature of the arc-shaped positioning grooves at the fixed end 2 and the arc-shaped grooves of the clamps 4 are designed to accommodate various diameters of steel bars.

[0082] The clamps 4 connecting rods 3 on the outermost layer of stirrups or distribution bars 6 are on the same horizontal plane as the fixed end 2, that is, the angle between the cross connecting rod 3 and the threaded compression rod 1 is 90°. The clamp connecting rods of the sub-outer layer of reinforcement or steel 5 are at a certain angle to the fixed end 2, and the angle between them and the threaded compression rod 1 is greater than 90°. The different curvatures of the two pairs of clamps are adapted to stirrups, distribution bars and sub-outer layer reinforcement or steel of different diameters, so that the fixed end of the cross clamp is firmly positioned.

[0083] The rotating double-layer sleeve 11 has no fewer than four tongues 8, and the cumulative length of the width of each tongue is no less than half the circumference, so as to ensure the overall rigidity and load-bearing requirements of the rotating double-layer sleeve 11, and to be able to be firmly connected with the inserted plug 7; the internally threaded sleeve 9 is connected to the separating stiffening plate 10; the internally threaded sleeve 9, the tongue 8, and the separating stiffening plate 10 are made as an integral component.

[0084] The circumferential surface of the insert 7 is made into an uneven and rough surface except for the insertion section or the contact surface with the tongue 8, and a "well"-shaped pattern of a certain depth is engraved on both ends to effectively bond with the concrete material to form an integral reinforced concrete structure.

[0085] In this embodiment, the cross clamp fixed end, the rotating double-layer sleeve 11, the fastening nut 13, and the spring washer 12 can be made of materials consistent with building steel bars and steel, or related materials with temperature expansion and contraction rates consistent with concrete and building steel; the insert 7 is made of stone cutting or concrete of the same grade as the building structure.

[0086] The construction method of the reinforced concrete protective layer positioning device for reinforced concrete prefabricated beams and piles of the device of this embodiment is as follows:

[0087] Step (1) Carefully read and study the steel bar and steel structure drawings of reinforced concrete and prestressed reinforced concrete structures to determine the type and size of the outermost and second outermost steel bars or steel on the bottom and side surfaces of the structure, as well as the thickness of the protective layer.

[0088] Step (2): Based on the steel bar and steel material design drawings of reinforced concrete and prestressed reinforced concrete structures, and taking the designed positions of the stressed steel bars and steel materials as the basis, calculate the cutting length of each steel bar and steel material, and manufacture and shape them according to the type specified in the design.

[0089] Step (3): Calculate the number of devices of the present invention required on the bottom surface based on the weight of the steel bars and the steel forming structure skeleton, the distribution of steel bars or stirrups on the bottom surface, and the supporting weight that the device of the present invention can bear, and plan and arrange the devices of the present invention on the bottom surface and sides.

[0090] Step (4): accurately lay out the positions of the distribution bars or stirrups on the bottom mold or the pedestal and mark them. At the same time, clearly mark the points of the device of the present invention as planned and arranged according to the above step (3).

[0091] Step (5): screw the fastening nut 13 into the threaded pressure rod 1 at the fixed end of the cross clamp, put on the spring washer 12, insert the insert block 7 into the rotating double-layer sleeve 11, rotate the internal threaded sleeve 9 of the rotating double-layer sleeve 11 into the threaded pressure rod 1 at the fixed end of the cross clamp to the position required for the insulation layer thickness, and tighten the fastening nut 13 to position the rotating double-layer sleeve 11.

[0092] Step (6): Place the assembled device of the present invention according to the cross position of the steel bars marked on the bottom mold, and install the outermost stirrups or distribution bars 6 and the second outermost steel bars or steel 5 on the arc-shaped positioning groove of the fixed end 2. At the same time, use the steel bar binding wire to bind and connect with the steel bars at the clamp 4, and shape other steel bars according to the designed steel bar skeleton structure.

[0093] Step (7), after the steel skeleton is formed, check whether the thickness of the bottom mold steel bar protective layer is accurate. If there is a difference, loosen the fastening nut 13, rotate the rotating double-layer sleeve 11 to adjust, and then tighten the fastening nut 13 again.

[0094] Step (8): Install the device of the present invention at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end 2 is clamped on the outermost steel bar at the intersection of the steel bars, and the clamp 4 is tied and connected with the outermost and second outer layer steel bars with binding wire.

[0095] Step (9): Install and fix the side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut 13, rotate the double-layer sleeve 11 to adjust, and then tighten the fastening nut 13 again.

[0096] Step (10): pour concrete in layers and in sequence, and cure it. Remove the formwork after reaching the specified demoulding time and strength. Example 2

[0097] In the millimeter-level reinforced concrete steel bar protective layer positioning device of this embodiment, if the rotating double-layer sleeve 11 is made of rust-free related steel or cast iron, the insert 7 can be eliminated and the tongue 8 can be extended accordingly.

[0098] The rotating double-layer sleeve 11 is connected by a rotating thread through the threaded pressure rod 1 on the fixed end of the cross clamp. Example 3

[0099] The reinforced concrete reinforcement protective layer positioning device of this embodiment has the same structure as that of embodiment 1, except that the cross connecting rod of the arc-shaped positioning groove is made to be consistent with the curvature of the circular stirrup. Example 4

[0100] The structure of the reinforced concrete reinforcement protective layer positioning device of this embodiment is the same as that of embodiment 1. The construction method of the reinforced concrete reinforcement protective layer positioning device of the pre-tensioned prestressed reinforced concrete precast beam of this embodiment is as follows:

[0101] Step (1) Preparation: Same as steps (1) to (3) in Example 1.

[0102] Step (2) The geometric dimensions and elevation of the pre-tensioned pedestal are precisely positioned, and the elevation of the pedestal top surface and the distance between the steel strands or wires after tensioning are in accordance with the requirements of the design drawings.

[0103] Step (3) accurately lay out the bottom distribution reinforcement position on the pedestal and mark it, and at the same time calculate the weight of the steel strand or steel wire after the steel skeleton is loaded. The principle when considering the installation quantity of the device of this embodiment is that the steel strand or steel wire does not bear the load transmitted by the steel skeleton, ensure that the tension of the steel strand or steel wire is accurate, and plan the point position of the device of this embodiment and mark it clearly.

[0104] Step (4) pre-tensioning the steel strands or steel wires, wherein the pre-tensioning stress does not exceed 5 to 8% of the design tensioning force, to ensure that the steel strands or steel wires are taut and perform the steel skeleton forming operation.

[0105] Step (5): Screw the fastening nut 13 into the threaded pressure rod 1 at the fixed end of the cross clamp, put on the spring washer 12, insert the insert block 7 into the tongue 8 of the rotating double-layer sleeve 11, rotate the internal threaded sleeve 9 of the rotating double-layer sleeve 11 into the threaded pressure rod 1 at the fixed end of the cross clamp to the position required for the insulation layer thickness, and tighten the fastening nut 13 to position the rotating double-layer sleeve 11.

[0106] Step (6) The assembled device of this embodiment is preliminarily installed at the position of the bottom distribution reinforcement, so that the arc-shaped positioning groove of the fixed end 2 is clamped with the distribution reinforcement, and the clip on the cross connecting rod along the arc-shaped positioning groove is tied with the distribution reinforcement. Then, the insert 7 is inserted through the gap between the steel strand or steel wire and the pedestal, and the clip on the cross connecting rod perpendicular to the arc-shaped positioning groove is clamped with the steel strand or steel wire, and then fixed with iron wire. At the same time, the nodes of the distribution reinforcement and the steel strand or steel wire are tied to keep the distribution reinforcement and the steel strand or steel wire close to each other, and other steel bars are formed according to the designed steel skeleton structure.

[0107] Step (7) After the steel skeleton is formed, check whether the steel geometric dimensions and steel types of the steel skeleton are correct, tension the steel strands or wires to the design stress, and check whether the thickness of the steel protection layer of the pedestal distribution is accurate. If there is a difference, loosen the fastening nut 13, rotate the double-layer sleeve 11 to adjust, and then tighten the fastening nut 13 again to accurately position it at the millimeter level.

[0108] Step (8) The device of this embodiment is installed at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end 2 is clamped on the outermost steel bar, and the clamp 4 is tied and connected with the outermost and second outer layer steel bars with binding wire.

[0109] Step (9) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut 13, rotate the double-layer sleeve 11 to adjust, and then tighten the fastening nut 13 again.

[0110] Step (10) Concrete is poured layer by layer and in sequence, and cured. After the specified demoulding time and strength are reached, the formwork is removed and the tensile stress is released. Example 5

[0111] The structure of the reinforced concrete steel bar protective layer positioning device of this embodiment is the same as that of embodiment 1. The construction method of the reinforced concrete steel bar protective layer positioning device of the cast-in-place reinforced concrete beam of this embodiment is as follows:

[0112] Step (1) Carefully read and study the reinforcement structure diagram of the cast-in-place reinforced concrete structure to determine the type and size of the outermost and second outermost reinforcements on the bottom and side surfaces of the structure, as well as the thickness of the protective layer.

[0113] Step (2) Calculate the cutting length of each steel bar based on the steel bar structure design drawing of the cast-in-place reinforced concrete structure and the designed position of the stress-bearing steel bar, and shape it according to the type specified in the design.

[0114] Step (3) The support formwork is installed and the elevation is adjusted after pre-stressing. The strength, rigidity and flatness of the bottom formwork and side formwork meet the design requirements.

[0115] Step (4) calculates the number of devices of this embodiment required on the bottom surface based on the weight of the steel bar forming structure skeleton and embedded parts, the distribution of steel bars or stirrups on the bottom surface, and the supporting weight that can be borne by a single device of this embodiment, and plans and arranges the devices of this embodiment on the bottom surface and side surfaces.

[0116] Step (5) accurately lay out the positions of the distribution bars or stirrups on the bottom formwork and mark them. At the same time, plan and arrange the points of the device of this embodiment according to the above step (4) and clearly mark them on the template.

[0117] Step (6) Screw the fastening nut 13 of the device of this embodiment into the threaded pressure rod 1 at the fixed end of the cross clamp, put on the spring washer 12, insert the plug block 7 into the rotating double-layer sleeve 11, rotate the internal threaded sleeve 9 of the rotating double-layer sleeve 11 into the threaded pressure rod 1 at the fixed end of the cross clamp to the position required for the insulation layer thickness, and tighten the fastening nut 13 to position the rotating double-layer sleeve 11.

[0118] Step (7) The assembled device of this embodiment is placed according to the cross position of the steel bars marked on the bottom mold, and the outermost stirrups or distribution bars 6 and the second outermost steel bars or steel materials 5 are installed on the arc-shaped positioning groove of the fixed end 2. At the same time, the steel bars are tied and connected with the steel bars at the clamp 4 with the tying wire for tying the steel bars, and other steel bars are formed according to the designed steel bar skeleton structure. When the steel bars are divided into upper and lower layer structures, the spacing between the upper and lower layers is accurately fixed according to the conventional method.

[0119] Step (8) After the steel skeleton is formed, check whether the thickness of the bottom mold steel bar protective layer is accurate. If there is a difference, loosen the fastening nut 13, rotate the double-layer sleeve 11 to adjust, and then tighten the fastening nut 13 again.

[0120] Step (9) The device of this embodiment is installed at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end 2 is clamped on the outermost steel bar, and the clamp 4 is tied and connected with the outermost and second outer layer steel bars with binding wire.

[0121] Step (10) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut 13, rotate the double-layer sleeve 11 for adjustment, and then tighten the fastening nut 13 again.

[0122] Step (11) Concrete is poured in layers and in sequence, and cured. The support and formwork are removed after the specified demoulding time and strength are reached. Example 6

[0123] The structure of the reinforced concrete reinforcement protective layer positioning device of this embodiment is the same as that of Example 1, except that the cross connecting rod of the arc-shaped positioning groove is made to match the curvature of the circular stirrup. The construction method of the reinforced concrete protective layer positioning device of this embodiment for cast-in-place reinforced concrete bored piles is as follows:

[0124] Step (1) Carefully read and study the reinforcement structure diagram of the cast-in-place reinforced concrete bored pile structure to determine the type, size, quantity and protective layer thickness of the stirrups and main reinforcement.

[0125] Step (2) According to the steel structure design drawing of the cast-in-place reinforced concrete bored pile structure, the cutting length of each steel bar is calculated based on the designed position of the stress-bearing steel bar, and the steel bar is manufactured and formed according to the type specified in the design.

[0126] Step (3) Before drilling bored piles, the layout must be accurate and verified to be correct; the drilling process should be slow and even, the wall slurry consistency should be maintained, and the deviation of the hole should be checked at any time to make effective corrections.

[0127] Step (4) plans and arranges the minimum number and arc spacing required for one circle of the device of this embodiment based on the diameter of the bored cast-in-place pile reinforcement cage forming structure skeleton.

[0128] Step (5) Arrange a circle of the device of this embodiment on the bored pile reinforcement cage at intervals of 3 to 6 meters, and mark the bored pile reinforcement cage.

[0129] Step (6) Screw the fastening nut 13 of the device of this embodiment into the threaded pressure rod 1 at the fixed end of the cross clamp, put on the spring washer 12, insert the plug block 7 into the rotating double-layer sleeve 11, rotate the internal threaded sleeve 9 of the rotating double-layer sleeve 11 into the threaded pressure rod 1 at the fixed end of the cross clamp to the position required for the insulation layer thickness, and tighten the fastening nut 13 to position the rotating double-layer sleeve 11.

[0130] Step (7) Install the assembled device of this embodiment according to the marked position of the above step (5), the arc-shaped positioning groove of the fixed end 2 is clamped at the intersection of the stirrup and the main reinforcement, the clamp on the cross connecting rod along the arc-shaped positioning groove is spot welded to the stirrup, the clamp on the cross connecting rod perpendicular to the arc-shaped positioning groove is clamped to the main reinforcement and then spot welded, and the stability of the plug 7 of the device of this embodiment is checked.

[0131] Step (8) After the hole is drilled, the hole position, verticality and aperture are inspected. If the deviation of the hole position, verticality and aperture exceeds the specified value, the hole position, verticality and aperture should be corrected and then the hole should be cleaned.

[0132] Step (9) Use a crane or other lifting equipment to vertically lift the steel cage, align the center of the steel cage with the center of the drill hole, and slowly and evenly insert the steel cage into the hole. After reaching the height of the steel cage, fix the steel cage. When the steel cage needs to be extended, it should be welded while it is vertically lifted.

[0133] Step (10): lower the conduit and perform underwater concrete pouring.

[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A millimeter-level reinforced concrete reinforcement cover positioning device, characterized by: It includes a cross clamp fixing end, a fastening nut (13), a spring washer (12), and a rotating double-layer sleeve (11); The cross clamp fixed end comprises a fixed end (2), a clamp (4), a connecting rod (3) connecting the fixed end (2) and the clamp (4), and a threaded pressure rod (1) on the fixed end (2); The rotating double-layer sleeve (11) comprises a tongue (8), an internally threaded sleeve (9) and a separating stiffening plate (10); Small holes are provided in the radial direction on the internal threaded sleeve (9), and the concrete slurry fills the space inside the internal threaded sleeve through the small holes; The threaded pressure rod (1) on the fixed end of the cross clamp is connected to the fastening nut (13) by thread rotation, the spring washer (12) is placed between the fastening nut (13) on the threaded pressure rod (1) and the rotating double-layer sleeve (11), and the rotating double-layer sleeve (11) is connected to the threaded pressure rod (1) on the fixed end of the cross clamp by thread rotation; It also includes an insert (7), and the concrete slurry enters and fills the gap between the insert (7) and the separating stiffening plate (10); the tongue (8) of the rotating double-layer sleeve (11) is used to fix the inserted insert (7) through friction; the tongue (8) of the rotating double-layer sleeve (11) is not less than 4 pieces, and the cumulative length of the width of each piece is not less than half the circumference length; Small holes distributed in a plum blossom shape are provided radially on the internally threaded sleeve (9); The partition stiffening plate (10) is provided with plum blossom-shaped small holes distributed thereon, allowing concrete slurry to enter the gap between the filling plug (7) and the partition stiffening plate (10); The fixed end of the cross clamp is arranged at the intersection of the outermost stirrup or distribution bar (6) and the second outermost steel bar or steel material (5) of the steel frame structure, and the arc-shaped positioning groove of the fixed end (2) is clamped at the intersection of the outermost stirrup or distribution bar (6) and the second outermost steel bar or steel material (5). The cross clamp is clamped on the outermost stirrup or distribution bar (6) and the second outermost steel bar or steel material (5) through the clamp (4) and is tied or welded to the steel frame.

2. The device according to claim 1, characterized in that: The cross connecting rod (3) and the threaded pressure rod (1) are at an angle of 90 degrees, and the clamp connecting rod of the secondary outer layer steel bar or steel material (5) is at an angle to the fixed end (2), and the angle to the threaded pressure rod (1) is greater than 90 degrees.

3. A construction method for a millimeter-level reinforced concrete reinforcement protective layer positioning device, characterized by: The device according to claim 1 comprises the following steps: Step (1) Calculate the number of devices required on the bottom surface based on the weight of the steel bars and the steel forming structure skeleton, the distribution of steel bars or stirrups on the bottom surface, and the supporting weight that the device can bear, and plan and arrange the devices on the bottom surface and side surfaces; Step (2) accurately lay out the positions of the distribution bars or stirrups on the bottom mold or pedestal and mark them, and clearly mark the points where the device is planned and arranged according to the above step (1); Step (3) screw the fastening nut (13) into the threaded pressure rod (1) at the fixed end of the cross clamp, put on the spring washer (12), insert the plug (7) into the rotating double-layer sleeve (11), rotate the internal threaded sleeve (9) of the rotating double-layer sleeve (11) into the threaded pressure rod (1) at the fixed end of the cross clamp to the position required for the thickness of the insulation layer, and tighten the fastening nut (13) to position the rotating double-layer sleeve (11); Step (4) placing the assembled device according to the cross position of the steel bars marked on the bottom mold, and installing the outermost stirrups or distribution bars (6) and the second outermost steel bars or steel (5) on the arc-shaped positioning groove of the fixed end (2) thereof, and at the same time using the steel bar binding wire to bind and connect with the steel bars at the clamp (4), and forming other steel bars according to the designed steel bar skeleton structure; Step (5) After the steel frame is formed, check whether the thickness of the bottom mold steel bar protective layer is accurate. If there is a difference, loosen the fastening nut (13), rotate the double-layer sleeve (11) to adjust, and then tighten the fastening nut (13) again; Step (6) installing the device at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end (2) is clamped on the outermost steel bar, and the clamp (4) is tied and connected with the outermost and second outer layer steel bars with binding wire; Step (7) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut (13), rotate the double-layer sleeve (11) to adjust, and then tighten the fastening nut (13) again; Step (8) pouring concrete in layers and in sequence, and curing it, and removing the formwork after reaching the specified demoulding time and strength.

4. A construction method for a millimeter-level reinforced concrete reinforcement protective layer positioning device, characterized by: The device according to claim 1 comprises the following steps: Step (1) The geometric dimensions and elevation of the pre-tensioned pedestal are accurately positioned, and the elevation of the pedestal top surface and the distance between the steel strands or steel wires after tensioning are in accordance with the requirements of the design drawings; Step (2) accurately lay out the bottom distribution reinforcement position on the pedestal and mark it, and at the same time calculate the weight of the steel strand or steel wire after the steel skeleton is loaded. The principle when considering the installation quantity of the device is that the steel strand or steel wire does not bear the load transmitted by the steel skeleton, ensure that the tension of the steel strand or steel wire is accurate, and plan the point of the device and mark it clearly; Step (3) pre-tensioning the steel strands or steel wires, wherein the pre-tensioning stress does not exceed 5 to 8% of the design tensioning force, to ensure that the steel strands or steel wires are taut and perform steel skeleton forming operations; Step (4) screw the fastening nut (13) into the threaded pressure rod (1) at the fixed end of the cross clamp, put on the spring washer (12), insert the plug (7) into the tongue (8) of the rotating double-layer sleeve (11), rotate the internal threaded sleeve (9) of the rotating double-layer sleeve (11) into the threaded pressure rod (1) at the fixed end of the cross clamp to the position required for the thickness of the insulation layer, and tighten the fastening nut (13) to position the rotating double-layer sleeve (11); Step (5) preliminarily installs the assembled device at the position of the bottom distribution reinforcement, so that the arc-shaped positioning groove of the fixed end (2) is clamped with the distribution reinforcement, and the clamp on the cross connecting rod (3) along the arc-shaped positioning groove is tied with the distribution reinforcement, and then the gap between the steel strand or steel wire and the pedestal is inserted, and the plug (7) contacts the bottom surface of the pedestal, and the clamp on the cross connecting rod (3) perpendicular to the arc-shaped positioning groove is clamped with the steel strand or steel wire, and is fixed with iron wire; at the same time, the nodes of the distribution reinforcement and the steel strand or steel wire are tied to keep the distribution reinforcement and the steel strand or steel wire close to each other, and other steel bars are formed according to the designed steel skeleton structure; Step (6) After the steel skeleton is formed, check whether the steel geometric dimensions and steel types of the steel skeleton are correct, tension the steel strands or wires to the design stress, and check whether the thickness of the steel protection layer of the pedestal distribution is accurate. If there is a difference, loosen the fastening nut (13), rotate the double-layer sleeve (11) to adjust, and then tighten the fastening nut (13) again to perform millimeter-level accurate positioning; Step (7) installing the device at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end (2) is clamped on the outermost steel bar, and the clamp (4) is tied and connected with the outermost and second outer layer steel bars with binding wire; Step (8) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut (13), rotate the double-layer sleeve (11) to adjust, and then tighten the fastening nut (13) again; Step (9) Concrete is poured layer by layer and in sequence, and cured. After the specified demoulding time and strength are reached, the formwork is removed and the tensile stress is released.

5. A construction method for a millimeter-level reinforced concrete reinforcement protective layer positioning device, characterized by: The device according to claim 1 comprises the following steps: Step (1) According to the steel structure design drawing of the cast-in-place reinforced concrete structure, the cutting length of each steel bar is calculated based on the designed position of the stress-bearing steel bars, and the steel bars are manufactured and formed according to the type specified in the design; Step (2) The support formwork is installed and pre-pressed to adjust the elevation. The strength, rigidity and flatness of the bottom formwork and side formwork meet the design requirements. Step (3) calculating the number of the devices required on the bottom surface based on the weight of the steel bar forming structure skeleton and embedded parts, the distribution of steel bars or stirrups on the bottom surface, and the supporting weight that can be borne by using a single device, and planning and arranging the devices on the bottom surface and side surfaces; Step (4) accurately lay out the distribution reinforcement or stirrup positions on the bottom form and mark them, and at the same time plan and arrange the points of the device according to the above step (3) and clearly mark them on the template; Step (5) screwing the fastening nut (13) of the device into the threaded pressure rod (1) at the fixed end of the cross clamp, putting on the spring washer (12), inserting the plug (7) into the rotating double-layer sleeve (11), rotating the internal threaded sleeve (9) of the rotating double-layer sleeve (11) into the threaded pressure rod (1) at the fixed end of the cross clamp to the position required for the thickness of the protective layer, and tightening the fastening nut (13) to position the rotating double-layer sleeve (11); Step (6) placing the assembled device according to the cross position of the steel bars marked on the bottom mold, and installing the outermost stirrups or distribution bars (6) and the second outermost steel bars or steel (5) on the arc-shaped positioning groove of the fixed end (2) thereof, and at the same time using the steel bar binding wire to bind and connect with the steel bars at the clamp (4), and forming other steel bars according to the designed steel bar skeleton structure. When the steel bars are divided into upper and lower layer structures, the spacing between the upper and lower layers is accurately fixed according to the conventional method; Step (7) After the steel frame is formed, check whether the thickness of the bottom mold steel bar protective layer is accurate. If there is a difference, loosen the fastening nut (13), rotate the double-layer sleeve (11) to adjust, and then tighten the fastening nut (13) again; Step (8) installing the device at the intersection of the stirrups and the second outer layer of steel bars of the side steel bar skeleton according to the planned layout, the arc-shaped positioning groove of the fixed end (2) is clamped on the outermost steel bar, and the clamp (4) is tied and connected with the outermost and second outer layer steel bars with binding wire; Step (9) Install the fixed side formwork and check the thickness of the steel bar protective layer. If any deviation is found, loosen the fastening nut (13), rotate the double-layer sleeve (11) to adjust, and then tighten the fastening nut (13) again; Step (10) Concrete is poured layer by layer and in sequence, and cured. The support and formwork are removed after the specified demoulding time and strength are reached.

6. A construction method for a millimeter-level reinforced concrete reinforcement protective layer positioning device, characterized by: The device according to claim 1 comprises the following steps: Step (1) According to the steel structure design drawing of the cast-in-place reinforced concrete bored pile structure, the cutting length of each steel bar is calculated based on the designed position of the stress-bearing steel bar, and the steel bar is manufactured and formed according to the type specified in the design; Step (2) The bored pile must be accurately laid out before drilling and checked for accuracy; the drilling process should be slow and even, the wall slurry consistency should be maintained, and the deviation of the hole should be checked at any time to make effective corrections; Step (3) planning and arranging the minimum number and arc spacing required for one circle of the device according to the diameter of the bored pile reinforcement cage forming structure skeleton; Step (4) arranging the device on the bored pile reinforcement cage at intervals of 3 to 6 meters, and marking the bored pile reinforcement cage; Step (5) screwing the fastening nut (13) of the device into the threaded pressure rod (1) at the fixed end of the cross clamp, putting on the spring washer (12), inserting the plug (7) into the rotating double-layer sleeve (11), rotating the internal threaded sleeve (9) of the rotating double-layer sleeve (11) into the threaded pressure rod (1) at the fixed end of the cross clamp to the position required for the thickness of the protective layer, and tightening the fastening nut (13) to position the rotating double-layer sleeve (11); Step (6) Install the assembled device according to the marked position of the above step (4), the arc-shaped positioning groove of the fixed end (2) is clamped at the intersection of the stirrup and the main reinforcement, the clamp on the cross connecting rod (3) along the arc-shaped positioning groove is spot-welded to the stirrup, the clamp on the cross connecting rod (3) perpendicular to the arc-shaped positioning groove is clamped to the main reinforcement and then spot-welded, and the stability of the device plug (7) is checked; Step (7) After the hole is drilled, the hole position, verticality and hole diameter are inspected. If the deviation of the hole position, verticality and hole diameter exceeds the specified value, the hole position, verticality and hole diameter should be corrected and then the hole should be cleaned. Step (8) Use a crane or other lifting equipment to vertically lift the steel cage, align the center of the steel cage with the center of the drill hole, slowly and evenly insert the steel cage into the hole, and fix the steel cage after reaching the height of the steel cage; when the steel cage needs to be extended, it should be welded and extended while it is vertically lifted; Step (9) lowers the conduit and performs underwater concrete pouring.

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