Prestressed reinforced concrete protective layer sleeve method pier column construction process and equipment

Abstract

The present application relates to the field of reinforced concrete pier construction, in particular to a prefabricated reinforced concrete protective layer sleeve method pier construction process and equipment. The prefabricated reinforced concrete protective layer sleeve method pier construction process is to first prefabricate the pier column steel reinforcement protective layer sleeve, then install it to the pier design position, and through the vertical reinforcement connection, annular reinforcement and vertical main reinforcement welding, center concrete pouring and other processes, the pier construction process is repeatedly installed and poured. The construction process is suitable for circular cross-section reinforced concrete piers with a diameter range of 1-2m. The prefabricated reinforced concrete protective layer sleeve equipment includes an outer mold, a modular inner mold, a bottom plate, a top mold and other auxiliary components. The present application combines the concrete filled steel tube pier and the cylindrical pier integral pouring process, retains the characteristics of corrosion resistance, low cost and consistent appearance of the concrete protective layer, solves the problem of prefabricated pier hoisting difficulty, and improves the operation efficiency and facilitates standardization promotion.

Description

Technical Field

[0001] This invention relates to the field of reinforced concrete pier construction, specifically to a precast reinforced concrete protective layer sleeve method for pier construction and related equipment. Background Technology

[0002] In bridge engineering, concrete piers can be either hollow or solid. Among solid piers, cylindrical piers are the most common and are frequently found in highway bridges, municipal overpasses, approach bridges of large bridges, and other small and medium-sized bridge projects.

[0003] In the concrete construction of bridge piers, the first method is the common on-site assembly and casting of concrete piers using steel formwork. Each pour is approximately 4-6 meters high. Reinforcing cages are prefabricated at a steel processing plant and then transported to the site for connection. This method is subject to strict control over the construction sequence and formwork cycle, resulting in a long construction period. Furthermore, the construction quality is greatly affected by the skill level of the construction workers, making it difficult to guarantee key quality indicators for the piers, such as the thickness of the concrete cover, the spacing of the reinforcing bars, and the appearance of the piers. The second method is prefabricated pier construction. This is a newer technology that improves pier quality and construction progress. However, its disadvantages include difficulties in hoisting large structures and stringent requirements for installation precision. Summary of the Invention

[0004] The purpose of this invention is to address the problems of long construction periods, quality affected by the technical level of construction personnel, and difficulties in hoisting precast piers caused by commonly used construction techniques in pier concrete construction. The invention designs a precast reinforced concrete protective layer sleeve method for pier construction technology and equipment to improve work efficiency and facilitate standardization.

[0005] In a first aspect, this application provides a construction process for precast reinforced concrete protective layer sleeve method for pier columns, which adopts the following technical solution, including the following steps:

[0006] S100, prefabricated protective sleeve;

[0007] S200 uses a straight threaded sleeve to connect the vertical main reinforcement of the pier column, ensuring that the vertical main reinforcement of the pier column is coaxial.

[0008] S300, protective layer sleeve hoisting and transportation, vertically hoisting the cured protective layer sleeve to the top of the construction site;

[0009] S400, First protective sleeve positioning and installation;

[0010] S500, secondary and above protective layer sleeve positioning installation;

[0011] S600, vertical main reinforcement is welded to the circumferential reinforcement of the protective sleeve;

[0012] S700, concrete pouring at the center of the protective sleeve;

[0013] S800, central concrete curing;

[0014] S900, the next cycle of pier construction begins when the central concrete strength reaches or exceeds the specified strength. This process repeats steps S200 to S800.

[0015] Furthermore, step S100 specifically includes the following steps:

[0016] S101, Template size design: Based on the design values ​​of the pier diameter and height in the project, design the size of the protective layer sleeve template for installation and pouring.

[0017] S102, Bottom mold outer ring and outer mold installation and fixation, 4 limit rods are inserted;

[0018] S103, rotate the upper bracket to torsion lever of the inner mold support, unfold the modular inner mold, lower the inner ring of the top mold, raise the lower inner mold support plate, and remove the central shaft of the support from the central hole of the bottom plate. Lift the outer ring of the bottom mold, the modular inner mold, the inner ring of the top mold, the inner mold support plate, the inner mold support, and the central shaft of the support as a whole to the ground; spray release agent on the outer ring of the bottom mold, the modular inner mold, the inner ring of the top mold, the inner mold support plate, and the inner ring of the bottom mold.

[0019] S104, the protective sleeve circumferential steel bars are cut to a fixed length and then bent into a spiral shape slightly smaller than the outer diameter of the modular inner mold on the processing equipment. The protective sleeve circumferential wire rod steel bars are fixed from top to bottom in the steel bar groove of the modular inner mold, and the upper and lower ends are respectively closed-loop welded together.

[0020] S105, hoist the modular inner mold, bottom outer mold, top inner mold, inner mold support plate, inner mold bracket, and bracket central shaft, which have been installed with protective sleeve circumferential reinforcement, into the outer mold. Insert the lower end of the bracket central shaft into the center hole of the bottom plate and lift the top inner mold.

[0021] S106, concrete pouring, the material is evenly distributed along the edge of the template using a hopper and a hose, and the pouring process uses an attached vibrator with an immersion vibrator for compaction.

[0022] S107 When the concrete is poured to near the top surface of the formwork, install the outer ring of the top formwork, vibrate and press down at the same time, and the concrete will emerge from the inner ring until the outer ring of the top formwork is tightly attached to the top of the outer formwork. Then lower the inner ring of the top formwork until the inner ring of the top formwork is tightly attached to the top of the modular inner formwork.

[0023] S108, after standing and initial setting, remove the inner ring of the top mold, and start curing with the mold on after 24 hours. When the concrete strength reaches the specified value, prepare to demold.

[0024] S109, Demolding process: Remove the outer ring of the top mold, the modular inner mold and the 4 limiting rods in sequence. Use a special lifting tool to slowly lift the protective layer sleeve together with the inner ring of the bottom mold and transfer it to the curing location. The outer mold together with the outer ring of the bottom mold is left on the base. Replace the inner ring of the bottom mold and prepare for the next cycle.

[0025] S110, repeat steps S101~S109, and perform cyclical operations.

[0026] Furthermore, in step S400, the installation of the vertical main reinforcement and the positioning of the protective sleeve are carried out simultaneously; before the construction of the pier column, a 5-10cm annular groove is excavated in the concrete around the outer side of the pre-embedded reinforcement of the pier column to form the bottom installation groove of the first section of the protective sleeve. The first section of the protective sleeve is embedded in the annular groove, and the vertical main reinforcement and the circumferential reinforcement of the protective sleeve are welded stably. The gap on the outside of the annular groove is sealed with mortar.

[0027] Furthermore, in step S500, before installing the secondary and higher protective layer sleeves, ensure the accurate position of the vertical main reinforcement bars. The exposed vertical main reinforcement bars should be temporarily tied and fixed to the steel reinforcement ring to facilitate the hoisting of the secondary and higher protective layer sleeves. The interface end of the secondary protective layer sleeve is inserted into the insertion end of the current protective layer sleeve. A layer of cement or pressure-reducing slurry is applied to the joint of the protective layer sleeve as a sealing adhesive. After checking and testing that the protective layer sleeve is accurately positioned, the vertical main reinforcement bars are welded to the circumferential reinforcement bars of the protective layer sleeve.

[0028] Furthermore, in step S600, the vertical main reinforcement and the circumferential reinforcement of the protective sleeve should be welded tightly and firmly. When installing the protective sleeve, each intersection of reinforcements should be welded to maximize the overall stability. The reinforcements in the secondary and above protective sleeves should be welded in a way that involves full welding or skip welding at intersections.

[0029] Furthermore, in step S700, after the protective sleeve of the pier column is installed to an appropriate height, the center concrete is poured in a timely manner. The concrete is poured using methods such as pumping, bucketing, and screw conveying, and is poured in layers and vibrated. When using a high-power vibrator, a safe distance is maintained between it and the protective sleeve. The entire concrete pouring process is carried out on a temporarily erected construction platform, and the protective sleeve must not be used as a support point for the operation. The concrete pouring height is more than 10cm lower than the upper edge of the protective sleeve of the current segment, and the construction joints of the two concrete pours are staggered from the splicing joints of the protective sleeve.

[0030] Furthermore, in step S800, after the central concrete is poured, the internal temperature gradually rises. When the ambient temperature is low, the protective layer sleeve is insulated and cured by covering it with a film and geotextile. The temperature difference between the inner and outer surfaces of the concrete is controlled below 25°C. The precast protective layer sleeve is cured by covering it with a film after demolding. When the construction period is tight, steam curing is used to shorten the demolding cycle.

[0031] Secondly, this application provides a precast reinforced concrete protective layer sleeve device, which can realize the precast reinforced concrete protective layer sleeve method for pier construction. The device includes a base, which comprises a concrete base. An I-beam support is provided on the upper outer side of the concrete base. A bottom plate is located within the area enclosed by the I-beams. The bottom plate has four through holes coaxial with four countersunk holes in the concrete base. Four limiting rods are inserted into the four countersunk holes of the concrete base. A support central shaft is inserted into the center of the bottom plate. The support central shaft is sequentially divided into a support central forward thread shaft and a support central reverse thread shaft. From bottom to top, the support central shaft is fitted with an inner mold support plate, two inner mold supports, and a top mold inner ring. The support central forward thread shaft and the support central reverse thread shaft are respectively located in the movable nut area at the upper center and lower center of the two inner mold supports. The four limiting rods abut against the two inner mold supports in pairs to maintain the stability of the inner mold supports. The inner mold support has a straight-edged inner mold abutting its outer circumference. Multiple straight-edged inner molds and multiple inclined inner molds are arranged alternately to form a circular structure. The straight-edged and inclined inner molds together constitute a modular inner mold. Inner mold hook sleeves are provided on both sides of the inner ring of the straight-edged inner mold, and inner mold hooks are provided on both sides of the inner ring of the inclined inner mold. The inner mold hook sleeves are fitted onto the inner mold hooks, thereby fixing the modular inner mold. When the inner mold support presses against the straight-edged inner mold, the multiple straight-edged inner molds and multiple inclined inner molds can be... The inclined inner mold is connected and closed to form a ring shape. The outer side of the modular inner mold is spirally provided with a rebar groove to fix the circumferential rebar of the protective sleeve. The top of the support central shaft is provided with a support torsion lever. The upper part of the I-beam supports the outer ring of the bottom mold. The outer mold is provided on the upper outer ring surface of the bottom mold outer ring. The outer mold is formed by two detachable semi-circular structures. The inner ring of the bottom mold is provided on the upper inner ring surface of the bottom mold outer ring. The top mold outer ring is movably provided on the top of the outer mold. An attached vibrator is provided on the outer side of the outer mold.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. Prefabricated concrete protective sleeves can maximize the roundness of the circumferential reinforcement of the protective sleeves. When installing vertical main reinforcement, since the reinforcement is installed one by one on site, it avoids the trouble of deformation during the stacking or transportation of the reinforcement cage. The vertical reinforcement is easier to accurately position, saving the process of assembling the formwork and making the reinforcement cage on site. It also increases the welding between the vertical main reinforcement and the circumferential reinforcement of the protective sleeve. Multiple welding points make the connection between the protective sleeves more stable.

[0034] 2. Precast protective layer sleeves offer advantages in terms of construction conditions and time. Construction can begin simultaneously with precast beams and other precast components in the early stages of the project. Precast formwork suffers less damage and deformation during use compared to on-site disassembly and assembly. They are lightweight, small in size, and easy to lift and transport. Quality inspection is conducted before the precast protective layer sleeves leave the site, using specialized lifting tools and fixed bases to protect them from external damage. Leveling and fixing the precast protective layer sleeves does not require screws or tie rods, reducing the risk of deformation and grout leakage associated with conventional molds.

[0035] 3. The use of precast reinforced concrete protective sleeves is no less effective than that of integrally cast piers in terms of load-bearing capacity. The corrosion resistance and impact resistance of the pier can be improved by increasing the strength and density of the concrete in the protective sleeve. The compressive strength of the solid structure can be improved by utilizing the hoop effect of the protective sleeve. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the installation structure of the precast reinforced concrete protective layer sleeve method for pier construction of the present invention;

[0037] Figure 2 This is a top view of the structure during the installation of the precast reinforced concrete protective layer sleeve method for pier columns according to the present invention.

[0038] Figure 3 This is a schematic diagram of the precast reinforced concrete protective sleeve structure of the present invention;

[0039] Figure 4 This is a schematic diagram of the precast reinforced concrete protective layer sleeve processing equipment of the present invention;

[0040] Figure 5 This is a partial exploded structural diagram of the precast reinforced concrete protective sleeve processing equipment of the present invention;

[0041] Figure 6 This is a top view schematic diagram of the precast reinforced concrete protective layer sleeve processing equipment of the present invention;

[0042] Figure 7 This is a schematic diagram of the structure of the precast reinforced concrete protective layer sleeve processing equipment of the present invention when the straight-side inner mold and the inclined-side inner mold are not connected and closed;

[0043] Figure 8 This is a schematic diagram of the circumferential reinforcement arrangement of the precast reinforced concrete protective sleeve of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1-Protective sleeve; 2-Protective sleeve interface end; 3-Protective sleeve spigot end; 4-Vertical main reinforcement; 5-Protective sleeve splice joint; 6-Bottom installation groove of the first protective sleeve section; 7-Circumferential reinforcement of the protective sleeve; 100-Concrete base; 101-Outer formwork; 102-Modular inner formwork; 1021-Beveled inner formwork; 1022-Straight inner formwork; 103-Inner ring of the bottom formwork; 104-Inner ring of the top formwork; 105-I-beam; 06-Inner mold support; 107-Top mold outer ring; 108-Bottom mold outer ring; 109-Support torsion lever; 110-Support center forward threaded shaft; 111-Support center reverse threaded shaft; 112-Support movable nut; 113-Inner mold hook; 114-Inner mold hook sleeve; 115-Attached vibrator; 116-Limit rod; 117-Inner mold support plate; 118-Support center shaft; 119-Rebar groove; 120-Base plate. Detailed Implementation

[0046] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0047] like Figure 1 , Figure 2 As shown, a construction process for a precast reinforced concrete protective layer sleeve method for pier columns includes the following steps:

[0048] S100, Prefabrication of protective sleeve; wherein, step S100 specifically includes the following steps:

[0049] S101, Template size design: Based on the design values ​​of the pier diameter and height in the project, design the size of the protective layer sleeve template for installation and pouring.

[0050] S102, Bottom mold outer ring and outer mold installation and fixation, 4 limit rods are inserted;

[0051] S103, rotate the upper bracket to torsion lever of the inner mold support, unfold the modular inner mold, lower the inner ring of the top mold, raise the lower inner mold support plate, and remove the central shaft of the support from the central hole of the bottom plate. Lift the outer ring of the bottom mold, the modular inner mold, the inner ring of the top mold, the inner mold support plate, the inner mold support, and the central shaft of the support as a whole to the ground; spray release agent on the outer ring of the bottom mold, the modular inner mold, the inner ring of the top mold, the inner mold support plate, and the inner ring of the bottom mold.

[0052] S104, the protective sleeve circumferential steel bars are cut to a fixed length and then bent into a spiral shape slightly smaller than the outer diameter of the modular inner mold on the processing equipment. The protective sleeve circumferential wire rod steel bars are fixed from top to bottom in the steel bar groove of the modular inner mold, and the upper and lower ends are respectively closed-loop welded together.

[0053] S105, hoist the modular inner mold, bottom outer mold, top inner mold, inner mold support plate, inner mold bracket, and bracket central shaft, which have been installed with protective sleeve circumferential reinforcement, into the outer mold. Insert the lower end of the bracket central shaft into the center hole of the bottom plate and lift the top inner mold.

[0054] S106, concrete pouring, the material is evenly distributed along the edge of the template using a hopper and a hose, and the pouring process uses an attached vibrator with an immersion vibrator for compaction.

[0055] S107 When the concrete is poured to near the top surface of the formwork, install the outer ring of the top formwork, vibrate and press down at the same time, and the concrete will emerge from the inner ring until the outer ring of the top formwork is tightly attached to the top of the outer formwork. Then lower the inner ring of the top formwork until the inner ring of the top formwork is tightly attached to the top of the modular inner formwork.

[0056] S108, after standing and initial setting, remove the inner ring of the top mold, and start curing with the mold on after 24 hours. When the concrete strength reaches the specified value, prepare to demold.

[0057] S109, Demolding process: Remove the outer ring of the top mold, the modular inner mold and the 4 limiting rods in sequence. Use a special lifting tool to slowly lift the protective layer sleeve together with the inner ring of the bottom mold and transfer it to the curing location. The outer mold together with the outer ring of the bottom mold is left on the base. Replace the inner ring of the bottom mold and prepare for the next cycle.

[0058] S110, repeat steps S101~S109, and perform cyclical operations.

[0059] S200 uses a straight threaded sleeve to connect the vertical main reinforcement of the pier column, ensuring that the vertical main reinforcement of the pier column is coaxial.

[0060] For S300 protective sleeves, hoisting and transportation are only permitted when the strength of the properly cured sleeve reaches 100% or more of the design value. Special lifting tools should be used for hoisting, and the sleeves should be hoisted vertically and not laid upside down to avoid damaging them. The transport vehicle should be equipped with a flexible base to achieve better vehicle shock absorption.

[0061] S400, the first protective layer sleeve is positioned and installed; the installation of the vertical main reinforcement is carried out simultaneously with the positioning of the protective layer sleeve. Before the construction of the pier column, a 5-10cm annular groove is excavated in the concrete around the outside of the pre-embedded reinforcement of the pier column to form the bottom installation groove of the first protective layer sleeve. The first protective layer sleeve is embedded in the annular groove, and the vertical main reinforcement is welded to the circumferential reinforcement of the protective layer sleeve for stability. The gap outside the annular groove is sealed with mortar.

[0062] S500, positioning and installation of the secondary and above protective layer sleeves; before installing the secondary and above protective layer sleeves, ensure the accurate position of the vertical main reinforcement bars. The exposed vertical main reinforcement bars should be temporarily tied and fixed to the steel reinforcement ring to facilitate the hoisting of the secondary and above protective layer sleeves; insert the interface end of the secondary protective layer sleeve into the insertion end of the current protective layer sleeve, apply a layer of cement or pressure reduction material slurry as a sealant to the joint of the protective layer sleeve, and after checking and testing that the positioning of the protective layer sleeve is accurate, weld the vertical main reinforcement bars to the circumferential reinforcement bars of the protective layer sleeve;

[0063] S600, vertical main reinforcement bars are welded to the circumferential reinforcement bars of the protective sleeve; the welding of vertical main reinforcement bars to the circumferential reinforcement bars of the protective sleeve should be tight and firm. When installing the protective sleeve, weld each intersection of reinforcement bars to maximize the overall stability; the reinforcement bars in the secondary and above protective sleeves are welded using full welding or skip welding at intersections.

[0064] S700, concrete pouring at the center of the protective sleeve; after the protective sleeve of the pier column is installed to an appropriate height, the center concrete should be poured in a timely manner, using methods such as pumping, bucketing, or screw conveying, and poured in layers and vibrated. When using a high-power vibrator, a safe distance should be maintained from the protective sleeve; the entire concrete pouring process should be carried out on a temporarily erected construction platform, and the protective sleeve should not be used as a support point for operation; the concrete pouring height should be more than 10cm lower than the upper edge of the protective sleeve of the current segment, and the construction joint of the two concrete pours should be staggered from the splicing joint of the protective sleeve;

[0065] S800, central concrete curing; after the central concrete is poured, the internal temperature gradually rises. When the ambient temperature is low, the protective layer sleeve is insulated and cured by covering it with a film and geotextile. The temperature difference between the inner and outer surfaces of the concrete is controlled below 25℃. The precast protective layer sleeve is cured by covering it with a film after demolding. When the construction period is tight, steam curing is used to shorten the demolding cycle.

[0066] S900, the next cycle of pier construction begins when the central concrete strength reaches or exceeds the specified strength. This process repeats steps S200 to S800.

[0067] like Figures 3-8As shown, a precast reinforced concrete protective layer sleeve device is used to realize the precast reinforced concrete protective layer sleeve method for pier construction. It includes a base, which comprises a concrete base 100. An I-beam 105 support is provided on the outer upper part of the concrete base 100. A bottom plate 120 is disposed within the area enclosed by the I-beam 105. The bottom plate 120 has four through holes coaxial with four countersunk holes in the concrete base 100. Four limiting rods 116 are inserted into the four countersunk holes of the concrete base 100. A central shaft 118 of the support is inserted into the center of the bottom plate 120. The support is divided into a central forward threaded shaft 110 and a central reverse threaded shaft 111. From bottom to top, the central shaft 118 is fitted with an inner mold support plate 117, two inner mold supports 106, and a top mold inner ring 104. The central forward threaded shaft 110 and the central reverse threaded shaft 111 are respectively located in the movable areas of the upper and lower centers of the two inner mold supports 106. Four limiting rods 116 abut against the two inner mold supports 106 in pairs to maintain their stability. The outer circumference of each inner mold support 106 is abutted by... A straight-edged inner mold 1022, and multiple straight-edged inner molds 1022 and multiple inclined-edged inner molds 1021 are arranged in an alternating circular structure. The straight-edged inner molds 1022 and the inclined-edged inner molds 1021 together constitute a modular inner mold 102. Inner mold hook sleeves 114 are provided on both sides of the inner ring of the straight-edged inner mold 1022, and inner mold hooks 113 are provided on both sides of the inner ring of the inclined-edged inner mold 1021. The inner mold hook sleeves 114 are fitted onto the inner mold hooks 113, thereby fixing the modular inner mold 102. When the inner mold support 106 presses against the straight-edged inner mold 1022, the multiple straight-edged inner molds 1022 and the multiple inclined-edged inner molds 1021 can be connected and closed to form a ring. The modular inner mold 102 has a spiral groove 119 on its outer side to fix the circumferential reinforcing bars 7 of the protective sleeve. The top of the support central shaft 118 is equipped with a support torsion lever 109. The upper part of the I-beam 105 supports the bottom mold outer ring 108. The outer ring surface of the bottom mold outer ring 108 is equipped with an outer mold 101. The outer mold 101 is composed of two detachable semi-circular structures that do not need to be disassembled when the demolding effect is good. The inner ring surface of the bottom mold outer ring 108 is equipped with a bottom mold inner ring 103. The top of the outer mold 101 is movably equipped with a top mold outer ring 107. The outer mold 101 is equipped with an attached vibrator 115 on its outer side.

[0068] The modular inner mold 102 is designed as 8 arc-shaped modules, symmetrically arranged. Among them, 4 straight-edge inner molds 1022 are connected to the inner mold support 106 and are removed first during demolding. The remaining 4 inclined inner molds 1021 are slidably connected to the straight-edge inner molds 1022 through the inner mold hooks 113. When the straight-edge inner molds 1022 move a certain distance, they will pull the inner mold hooks 113 to drive the inclined inner molds 1021 to complete demolding.

[0069] The precast reinforced concrete protective sleeve equipment is installed below ground level, with a height sufficient for the pouring of a single sleeve section. The base is a combination of an I-beam 105 and a concrete base 100. First, the concrete base 100 is poured, and then an I-beam 105 is placed around the concrete base 100. The interior of the I-beam 105 is filled and shaped with concrete to form the base plate 120.

[0070] The precast reinforced concrete protective layer sleeve method for pier construction involves a relatively thin protective layer thickness compared to the pipe diameter. To improve its impact resistance, the strength grade of the precast protective layer concrete should be increased to at least C40, with a slump of 160-200mm upon placement. Raw materials include 5-20mm continuously graded crushed stone, P.O42.5 silicate cement, Class F II fly ash, polycarboxylate superplasticizer, and medium-coarse sand with a fineness modulus of 2.3-3.2. The concrete mix design follows the specifications for ordinary concrete mix design.

[0071] The precast reinforced concrete protective sleeve method for pier construction involves first prefabricating the protective sleeve for the pier reinforcement, then installing it at the designed position of the pier, and repeatedly installing and pouring the pier through processes such as connecting the vertical reinforcement, welding the ring reinforcement to the vertical main reinforcement, and pouring the central concrete.

[0072] This process is suitable for reinforced concrete piers with circular cross-sections, ranging from 1 to 2 meters in diameter. It combines the techniques of steel-concrete composite pier construction and monolithic casting of cylindrical piers, retaining the corrosion resistance, low cost, and consistent appearance of the concrete protective layer. It utilizes the hoop effect of steel-concrete composite piers and the overall compressive strength enhancement properties of the longitudinal layered structure. Unlike concrete pipes used in hydraulic engineering, the inner wall of the precast reinforced concrete protective layer sleeve is designed in a gear-like pattern. This design serves two purposes: firstly, it increases the contact area between the new and old concrete, allowing for a more stable bond between the later-cast central concrete and the protective layer; secondly, it provides fixed positions for the vertical main reinforcement bars of the pier, enabling connection with the circumferential reinforcement bars within the precast sleeve and improving overall stability.

[0073] Unlike common precast pipe fittings, the ring-shaped reinforcing bars of the precast reinforced concrete protective sleeve need to be installed within the circumferential U-shaped groove of the inner mold. The portion of the reinforcing bars in contact with the inner mold is coated with a thin layer of cement slurry after demolding, which is easy to remove and facilitates welding to the vertical main reinforcement during later installation. Because the inner wall of the sleeve has an irregular cross-section, the inner mold can only be removed laterally. To facilitate disassembly and assembly, a telescopic inner mold support device was designed. To ensure concrete compaction, an attached vibrator is installed on the outer mold, and immersion vibration is used in conjunction with the pouring process.

[0074] The various embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A construction process of a prefabricated reinforced concrete protective layer sleeve method pier column, characterized in that, The method comprises the following steps: S100, prefabricating the protective layer sleeve; In step S100, the following steps are specifically included: S101, template size design, according to the design value of the diameter and height of the pier column in engineering, the size of the installation and pouring protective layer sleeve template is designed; S102, bottom mold outer ring, outer mold installation and fixation, inserting and placing four limiting rods; S103, rotating the support lever of the upper part of the inner mold support, unfolding the modular inner mold, falling the inner ring of the top mold, lifting the lower inner mold support plate, taking out the support center shaft from the center hole of the bottom plate, and hoisting the bottom mold outer ring, the modular inner mold, the inner ring of the top mold, the inner mold support plate, the inner mold support, and the support center shaft to the ground as a whole; the bottom mold outer ring, the modular inner mold, the inner ring of the top mold, the inner mold support plate, the inner ring of the bottom mold, and the insulating agent are sprayed; S104, protective layer sleeve hoop reinforcement is cut to size, and is bent into a spiral shape slightly smaller than the outer diameter of the modular inner mold on the reprocessing equipment, and the protective layer sleeve hoop reinforcement is fixed in the modular inner mold steel reinforcement groove from top to bottom, and the upper and lower ends are respectively closed loop welded and connected; S105, hoisting the modular inner mold with the installed protective layer sleeve hoop reinforcement, the bottom mold outer ring, the inner ring of the top mold, the inner mold support plate, the inner mold support, and the support center shaft into the outer mold, inserting the lower end of the support center shaft into the center hole of the bottom plate, and lifting the inner ring of the top mold; S106, concrete pouring, using a hopper and a rubber pipe to evenly distribute the material along the template edge, and using an attached vibrator combined with a vibrating rod inserted vibrating during the pouring process; S107, when the concrete is poured close to the top surface of the template, the outer ring of the top mold is installed, the concrete is poured from the inner ring, and the outer ring of the top mold is tightly fitted with the upper end of the outer mold, and then the inner ring of the top mold is lowered until the inner ring of the top mold is tightly fitted with the upper end of the modular inner mold; S108, standing, removing the inner ring of the top mold after initial setting, and starting to cure with the mold after 24 hours, and preparing to demold when the concrete strength reaches the specified value; S109, demolding process, sequentially removing the outer ring of the top mold, the modular inner mold, and the four limiting rods, slowly lifting the protective layer sleeve together with the inner ring of the bottom mold using a special lifting device, transferring to the curing site, leaving the outer mold together with the outer ring of the bottom mold on the base, replacing the inner ring of the bottom mold, and preparing for the next cycle; S110, repeating steps S101-S109, cyclically operating periodically; S200, connecting the vertical main reinforcement of the pier column by using a straight thread sleeve to ensure that the vertical main reinforcement of the pier column is coaxial; S300, hoisting and transporting the protective layer sleeve, vertically hoisting and transporting the cured protective layer sleeve above the construction site; S400, positioning and installing the first section of the protective layer sleeve; S500, positioning and installing the second section and above of the protective layer sleeve; S600, welding the vertical main reinforcement and the hoop reinforcement of the protective layer sleeve; S700, pouring the center concrete of the protective layer sleeve; S800, curing the center concrete; S900, next cycle pier construction, when the center concrete strength reaches the specified strength, the next cycle of pier construction is carried out, and steps S200-S800 are repeated.

2. The construction process of the precast reinforced concrete protective layer sleeve method pier column according to claim 1, characterized in that, In step S400, vertical main reinforcement installation is carried out simultaneously with the positioning of the protective layer sleeve; before the construction of the pier column, a 5-10 cm annular groove is excavated under the outer periphery of the pier column pre-embedded reinforcement, forming a first section protective layer sleeve bottom installation groove, the first section protective layer sleeve is embedded in the annular groove, the vertical main reinforcement is welded with the protective layer sleeve hoop reinforcement to stabilize, and the annular groove outer gap is sealed with mortar.

3. The construction technology of the prefabricated reinforced concrete protective layer sleeve method pier column according to claim 1, characterized in that, In step S500, before the installation of the second and subsequent protective layer sleeves, ensure the accurate position of the vertical main reinforcement, and the higher vertical main reinforcement should be temporarily tied and fixed on the reinforcement ring to facilitate the hoisting of the second and subsequent protective layer sleeves; the interface end of the second section protective layer sleeve is inserted into the socket end of the current section protective layer sleeve, a layer of cement or pressure reducing material grout is applied to the joint gap of the protective layer sleeve as a sealing adhesive, and after checking and detecting the accurate positioning of the protective layer sleeve, the vertical main reinforcement is welded on the protective layer sleeve hoop reinforcement.

4. The precast reinforced concrete cover tube method pier construction process according to claim 1, characterized in that, In step S600, the vertical main reinforcement and the protective layer sleeve hoop reinforcement should be tightly and firmly welded, and when installing the protective layer sleeve, each steel reinforcement intersection point should be welded to maximize the overall stability; the steel reinforcement welding in the second and subsequent protective layer sleeves should be all welded or cross-point skip welding.

5. The precast reinforced concrete cover tube method pier construction process according to claim 1, characterized in that, In step S700, after the protective layer sleeve of the pier column is installed to an appropriate height, the central concrete is poured in time, and pumping, hoisting, and spiral conveying methods are used for pouring, layer-by-layer pouring and vibration, and a safe distance should be maintained between the protective layer sleeve and the high-power vibration rod; the entire concrete pouring process is carried out on the temporarily erected construction platform, and the protective layer sleeve cannot be used as a support point for operation; the concrete pouring height is more than 10 cm above the upper edge of the current section protective layer sleeve, and the construction joints of two times of concrete are staggered with the joint gap of the protective layer sleeve.

6. The precast reinforced concrete cover tube method pier construction process according to claim 1, characterized in that, In step S800, after the central concrete is poured, the internal temperature gradually rises, and when the ambient temperature is low, the protective layer sleeve is kept warm and maintained, covered with film and geotextile, and the internal temperature difference of the concrete is controlled below 25°C; the precast protective layer sleeve is cured after demolding and covered with film, and when the construction period is tight, steam curing is used to shorten the demolding period.

7. A precast reinforced concrete protection layer sleeve device, capable of realizing the precast reinforced concrete protection layer sleeve method pier construction process according to any one of claims 1-6, characterized in that, The utility model provides a kind of prefabricated concrete base, including base, the base includes concrete base (100), the concrete base (100) upper outer side is provided with I-beam (105) support, bottom plate (120) is arranged in the area inside being surrounded by the I-beam (105), the bottom plate (120) is provided with 4 through holes with the 4 counterbores of the concrete base (100) coaxial, 4 counterbores of the concrete base (100) are inserted with 4 limit rods (116) respectively, the bottom plate (120) center is inserted with support center shaft (118), the support center shaft (118) is successively divided into support center positive screw shaft (110) and support center reverse screw shaft (111), the support center shaft (118) is respectively sleeved with inner mould support plate (117), two inner mould supports (106), top mould inner ring (104) from bottom to top, the support center positive screw shaft (110) and the support center reverse screw shaft (111) are arranged in the support movable nut (112) and the support movable nut (112) active area of center upper portion and center lower portion of two inner mould supports (106) respectively, 4 limit rods (116) are respectively abutted with two inner mould supports (106) two by two, keep the stability of the inner mould support (106), the circumferential outer side of the inner mould support (106) is provided with straight edge inner mould (1022) and is pressed on, multiple straight edge inner mould (1022) and multiple bevel edge inner mould (1021) are staggered and arranged to form circular structure, the straight edge inner mould (1022) and the bevel edge inner mould (1021) jointly constitute modular inner mould (102), the inner ring both sides of the straight edge inner mould (1022) are provided with inner mould hook sleeve pipe (114), the inner ring both sides of the bevel edge inner mould (1021) are provided with inner mould hook (113), the inner mould hook sleeve pipe (114) is sleeved with the inner mould hook (113), to fix modular inner mould (102) in turn, when the inner mould support (106) is pressed on the straight edge inner mould (1022), multiple straight edge inner mould (1022) and multiple bevel edge inner mould (1021) can be connected closed to form circular ring shape, the modular inner mould (102) outer side is provided with the bar dowel slot (119) of spiral, to fixed protection layer sleeve circumferential reinforcement (7), the support center shaft (118) top is provided with support torsion lever (109), the I-beam (105) upper portion is supported with bottom mould outer ring (108), the bottom mould outer ring (108) upper outer ring surface is provided with outer mould (101), the outer mould (101) is formed by two half circular structures detachable surrounding, the bottom mould outer ring (108) upper inner ring surface is provided with bottom mould inner ring (103), the outer mould (101) top end is movably provided with top mould outer ring (107), the outer mould (101) outer side is provided with attached vibrator (115).

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