Steel member protection structure during staged implementation of structural column
By using polyethylene foam protective sleeves and plastic board inner formwork combined with low-grade concrete in the phased implementation of structural columns, a multi-layer protective structure was formed, which solved the problems of rust and connection of steel bars or steel sections during phased construction, achieved efficient protection of steel bars or steel sections, and reduced construction workload and costs.
Patent Information
- Application Number
- CN202422811355.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-11-19
AI Technical Summary
During the phased implementation of structural columns, existing technologies make it difficult to effectively protect reserved steel bars or steel sections, especially when they are exposed to the outside for a long time. They are prone to rust and difficult to connect efficiently after construction is completed, resulting in a large workload for concrete pouring and demolition, affecting project progress and costs.
Polyethylene foam protective sleeves and plastic board inner formwork are combined with low-grade concrete or foam concrete to form a multi-layer protective structure, which isolates air and moisture, simplifies the demolition process, and achieves temporary protection of steel bars or steel sections through detachable rainproof protective covers and bolt connections.
It can effectively isolate steel bars or steel sections from contact with air and water, reduce the workload of concrete pouring and demolition, improve the safety and construction efficiency of steel bars or steel sections, and reduce project costs and construction period.
Smart Images
Figure CN223387008U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of structural engineering construction, in particular to a steel component protection structure when a structural column is implemented in stages. Background Art
[0002] The general implementation process for integrated property development projects above rolling stock bases is as follows: Construction of the platform is completed simultaneously with rail transit construction. The completed platform land enters the market through land transfer procedures, and secondary developers undertake integrated property development. This results in discontinuous construction between the above- and below-ground construction. Given the unique and systematic nature of development, it is subject to numerous external factors, resulting in uncertain development times.
[0003] In order to reserve greater flexibility for the development plan of the cover, usually only one platform is constructed during rail transit construction, and the second platform is implemented together with the cover property. The vertical components reserved for the cover platform are mostly conversion components or bear various loads such as the cover soil, landscape, etc., with large cross-sections and a lot of reinforcement.
[0004] In the process of promoting such projects, when phased development or batch implementation occurs and on-site construction cannot be completed continuously vertically, the steel bars of concrete columns or the steel-concrete columns and the steel sections need to be reserved for extension according to the force and structure. For phased construction situations such as cover development, where the overall number is large, the cross-section of individual components is large, and there is a lot of reinforcement, protection measures for reserved steel bars or steel sections are very important. In the short term, measures should be taken to protect the reserved steel bars or steel sections from rusting. In the long term, during construction, the steel bars or steel sections should be connected upward according to the structural requirements, and then concrete should be poured to form a vertical load-bearing component that is connected from top to bottom and transmits force smoothly. The short-term protection measures for the reserved steel bars and steel sections are only to isolate them from air corrosion, and they do not bear loads.
[0005] At present, the commonly used engineering practice is to cast low-grade concrete across the entire section. This approach does help prevent steel bars from rusting during the construction window period, but it requires a large amount of concrete and temporary distribution reinforcement to be removed during secondary development. The reserved steel bars are often damaged by the removal of supporting concrete and are difficult to repair.
[0006] In addition, previous research on steel protection has focused on reducing steel corrosion to improve the durability of new or existing concrete structures. Researchers have developed a series of protection measures, such as coating, sealing and film covering protection, patch repair, electrochemical chloride extraction, cathodic protection, rust inhibitors, etc.
[0007] All of the above methods rely on chemical reactions to passivate the rebar surface or alter the media environment at the rebar-concrete interface, delaying rebar corrosion and thereby extending the lifespan of concrete structures. Each method has its own applicability and corresponding impacts. For example, epoxy coatings are porous and hydrophilic, making them susceptible to wear during construction and failing to provide long-term corrosion protection. Thick coatings can also weaken the bond between rebar and concrete, leading to wider cracks in the structure and exacerbating rebar corrosion. Cathodic protection is primarily used in industrial water or seawater conditions. The design of impressed current protection systems within concrete structures is complex, and there is a high risk of failure throughout construction and operation. Rust inhibitors, whether incorporated for new construction or penetrating for renovation of existing structures, have certain impacts on concrete strength and the surrounding environment. For short-term exposure of rebar during work stoppages or large-scale concrete pours, protection options include simply spraying C15 strength mortar on the rebar or, in dry environments, wrapping the rebar with a specialized moisture-proof plastic sheeting, tightly wrapping the sheeting with plastic tape, and then covering it with a sleeve.
[0008] In summary, the protection of steel bars in permanent structures is mainly to improve the durability of concrete structures; steel bar covering films and sleeves are temporary protection methods for very short-term exposed steel bars. Their applicability to structural columns of projects that require phased development, when the reserved steel bars may be exposed for a long period of time, needs to be improved and verified. Summary of the Invention
[0009] The purpose of the utility model is to provide a steel component protection structure when the structural column is implemented in stages, based on the deficiencies of the above-mentioned existing technology, wherein only low-grade concrete or foam concrete is poured on the surrounding steel bars and formwork devices with different modules and steel bar protection devices that are conducive to the removal of concrete are used, thereby reducing the concrete pouring in the middle area of the component, the temporary fixing steel bar binding and removal work, thereby reducing the amount of abandoned projects, saving project costs and shortening construction period.
[0010] The purpose of this utility model is achieved by the following technical solutions:
[0011] A steel component protection structure for use when structural columns are implemented in stages, used to protect steel components reserved in future structural columns, the steel components extending out from the top surface of the future structural columns being cast this time, characterized in that the steel component protection structure includes a protective cover wrapped around the outer periphery of the steel component, plastic plate inner formwork is provided on the inner and outer sides of the protective cover, the plastic plate entirely encloses the steel component, a casting protective layer is cast on the inner and outer sides of the plastic plate, and the height of the casting protective layer is higher than the steel component.
[0012] The bottom of the plastic board inner formwork is embedded in the future structural column to be cast this time.
[0013] The top cover of the cast protective layer is provided with a rainproof protective cover.
[0014] The top of the cast protective layer is pre-embedded with embedded bolts for connecting with the rainproof protective cover, and the cast protective layer is connected to the rainproof protective cover in a detachable bolted manner through the embedded bolts.
[0015] The pouring protection layer is made of low-grade concrete or foam concrete that is easy to remove.
[0016] The protective cover is a polyethylene foam protective cover.
[0017] The steel components are longitudinal reinforcements reserved in the future structural columns of this casting. The heights of the longitudinal reinforcements are different, and the height of the casting protective layer covers all the longitudinal reinforcements.
[0018] The advantages of the utility model are:
[0019] 1) For structural members with large cross-sections and a large number of reinforcements, this method of hollow protection with reserved reinforcement can effectively isolate the air and avoid reinforcement modification. Compared with pouring concrete across the entire cross-section, it greatly saves the amount of concrete pouring and demolition work, as well as the distribution reinforcement for temporarily fixing the longitudinal reinforcement;
[0020] 2) The longitudinal reinforcement is protected from damage during concrete removal by the foam wrapping and the “J”-shaped plastic sheeting. Furthermore, the outer ring of the longitudinal reinforcement is encased in concrete, effectively blocking the corrosion from outside air and moisture, thereby improving the safety and effectiveness of the reserved longitudinal reinforcement.
[0021] 3) When the protective layer concrete is broken, due to the effect of the "J"-shaped plastic plate, it is only necessary to chisel shallow holes along the inner and outer circles at the bottom of the protective layer to remove it as a whole. The whole piece can be hoisted and removed, which greatly improves efficiency;
[0022] 4) When pouring the cover concrete, consider marking any areas that require removal. For example, mark the height of the bottom end of a "J"-shaped plastic sheet to facilitate identification of the starting point for chiseling, thereby minimizing chiseling. Select a number of horizontal spacing marks for the longitudinal reinforcement to facilitate vertical division of the cover concrete into small pieces. Mark the end position of the longitudinal reinforcement to facilitate horizontal division of the cover concrete.
[0023] 5) By pouring permanent concrete inside the steel section, the anti-corrosion coating area of the steel section and the long-term concrete removal project are reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a schematic structural diagram of the first embodiment of the present invention;
[0025] Figure 2 Two cross-sectional schematic diagrams of the first embodiment of the present utility model;
[0026] Figure 3 This is a schematic structural diagram of a template device for pouring a protective layer in accordance with the first embodiment of the present invention;
[0027] Figure 4 This is a schematic diagram of the structure of the first embodiment of the present utility model when it is dismantled;
[0028] Figure 5 This is a schematic structural diagram of the second embodiment provided by the present utility model;
[0029] Figure 6 This is a cross-sectional schematic diagram of the second embodiment of the present utility model;
[0030] Figure 7 This is a schematic structural diagram of a template device for pouring a protective layer according to the second embodiment of the present utility model;
[0031] Figure 8 This is a schematic diagram of the structure of the second embodiment of the present invention when it is dismantled. DETAILED DESCRIPTION
[0032] The following is a further detailed description of the features of the present invention and other related features through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art:
[0033] like Figure 1-8 As shown in the figure, numbers 1-17 respectively represent: long-term structural column 1 for this casting, permanent stirrups 2, reserved longitudinal reinforcement 3, reserved longitudinal reinforcement 4, polyethylene foam steel bar protective cover 5, plastic board inner formwork 6, L-shaped formwork 7, vertical bar formwork 8, short wooden support 9, low-grade concrete or foam concrete 10, rainproof protective cover 11, steel section 12, reserved permanent reinforcement 13, permanent concrete 14, flange inter-formwork 15, embedded bolts 16, and cutting position of temporary concrete cover 17.
[0034] Example 1: Figures 1 to 4 As shown, in this embodiment, the steel member protection structure is applied to the short-term protection of the steel bars of reinforced concrete frame columns when the structural columns are implemented in stages. The specific implementation method is as follows:
[0035] A future structural column 1 will be cast at a height h1 above the recently constructed structural surface elevation. The height of this future structural column 1 will comply with specifications and atlas requirements. The column cross-section, stirrups, concrete grade, and construction requirements for this height range are the same as those for future permanent structural columns. A protective layer of distributed reinforcement greater than 50mm is recommended for this future structural column 1 at height h1.
[0036] During this pour, the reserved longitudinal reinforcement is staggered and cut at a certain height h2 above the height of the future structural column 1. The first batch of steel bars is cut approximately 200mm above h1 to serve as reserved longitudinal reinforcement 3 (joint area percentage ≤ 50%), facilitating future mechanical connection of the reinforcement. The second batch of steel bars is cut approximately 200mm below h2 to serve as reserved longitudinal reinforcement 4.
[0037] Within the height range h2, the longitudinal reinforcements distributed around (reserved longitudinal reinforcements 3 and 4) are wrapped with polyethylene foam steel bar protective sleeves 5 to provide the first layer of protection for the longitudinal reinforcements. The thickness of the polyethylene foam steel bar protective sleeves 5 is preferably 10-20mm. Plastic board inner formwork 6 is erected on both sides of the polyethylene foam steel bar protective sleeves 5. Figure 2 As shown, the plastic board inner formwork 6 is entirely enclosed around the periphery of each longitudinal reinforcement to form a second layer of protection. When in use, the plastic board inner formwork 6 also serves as a formwork for the subsequent concrete pouring protective layer. The thickness of the plastic board inner formwork 6 is preferably 20-30 mm.
[0038] In this embodiment, to facilitate securement, the plastic panel inner formwork 6 has a longitudinal cross-sectional structure shaped like a "J" (a character in Chinese). Specifically, the plastic panel inner formwork 6 features an outwardly extending toe-shaped structure embedded above the h1 segment of the distribution reinforcement of the currently cast future structural column 1. Concrete is then poured in the h1 segment, thereby integrating the plastic panel inner formwork 6 with the currently cast future structural column 1 to form a self-stabilizing integral structure. The height of the "J"-shaped plastic panel inner formwork 6 is 200-220mm lower than the h2 height, ensuring that it just covers the reserved longitudinal reinforcement 3. If necessary, transverse ties can be installed between the waists of the inner and outer plastic panel inner formwork 6 to further enhance its stability.
[0039] Within the height range h2, the thickness of the protective layer on both sides of the reserved longitudinal reinforcement 3 and the reserved longitudinal reinforcement 4 shall not be less than the thickness of the permanent structure protective layer starting from the outer side of the plastic board inner formwork 6.
[0040] Within the height range of h2, the templates are supported on the inner and outer sides of the reserved longitudinal reinforcement 3 and the reserved longitudinal reinforcement 4. The structure of the template is as follows Figure 3 shown.
[0041] like Figure 3 As shown in the left figure, for a rectangular column, the outer formwork for the longitudinal reinforcement consists of four corner forms and several intermediate forms. The four corner forms are L-shaped forms 7, preferably with a length of 500-1000mm; the intermediate forms are vertical strip forms 8, preferably with a width of 300-500mm. L-shaped forms 7 and vertical strip forms 8 of varying sizes are combined to form the outer formwork that meets the requirements of the column cross-section. The inner formwork also consists of four corner forms and several intermediate vertical strip forms, and the combined dimensions meet the requirements for forming a protective casting layer.
[0042] like Figure 3As shown in the right figure, for a circular cross-section column, a number of vertical strip templates 8 can be fitted to form the inner and outer layer templates. In some cases, steel templates can also be used.
[0043] In this embodiment, the outer template adopts a conventional fixing scheme, and the inner template can be reinforced by arranging a cross short wooden support 9 inside. If necessary, the plastic board inner template 6 can be further fixed with a short support between it and the template.
[0044] Low-grade concrete or foam concrete 10 or other easily removable casting materials are poured between the inner and outer formworks and the plastic board inner formwork 6. After the low-grade concrete or foam concrete 10 is dense and reaches the age, the formwork is removed, and a casting protective layer is formed on the inner and outer sides of the plastic board inner formwork 6 to provide three-layer protection for the reserved longitudinal reinforcement.
[0045] The formwork will be removed after the reserved longitudinal reinforcement protective layer concrete (cast protective layer) reaches the age.
[0046] A plastic or aluminum rain cover 11 is placed on top of the cast protective layer to prevent rainwater from entering the column. During construction, bolts are embedded in the cast protective layer around the longitudinal reinforcement at a certain distance within the protective layer range on top of the longitudinal reinforcement to facilitate the fixing and installation of the rain cover 11 by bolts.
[0047] like Figure 4 As shown, during secondary development, at the cutting point 17 of the temporary concrete cover, notches are cut along the inner and outer protective layers of the reserved longitudinal bars to the inner plastic sheet formwork 6. This allows the reserved longitudinal bars to be separated from the protective layer concrete and the plastic sheet formwork 6. The polyethylene foam protective cover surrounding the reserved longitudinal bars is then removed to expose the reserved longitudinal bars 3 and 4.
[0048] If the removed longitudinal reinforcement cover concrete block is difficult to transport, it can be cut horizontally within the longitudinal reinforcement cover area and divided into three small blocks for transport. Alternatively, it can be cut vertically to avoid the longitudinal reinforcement and into strips. To ensure accurate avoidance of the reinforcement when chiseling or cutting, it can be marked during the concrete pouring.
[0049] The exposed reserved longitudinal reinforcement is connected and extended, and stirrups, tie reinforcement and concrete pouring are carried out according to the requirements of permanent structure.
[0050] Example 2: This example differs from Example 1 in that: Figures 4 to 8 As shown, this embodiment is applied to the short-term protection of steel and steel bars of steel-concrete frame columns. The main differences between its specific implementation method and the first embodiment are as follows:
[0051] Within the reserved height of the steel section 12, concrete is poured inside the flange of the steel section 12 according to the concrete grade and construction requirements of the permanent structure. Depending on the configuration of the column stirrups, whether to install reserved permanent stirrups 13 inside the steel section is determined. Anti-corrosion treatment is applied to the outer side of the flange of the steel section 12. Afterwards, permanent concrete 14 is poured inside the steel section 12.
[0052] In this embodiment, the permanent concrete 14 is poured by arranging inter-flange formwork 15 between the steel sections 12 to enclose a pouring space for the permanent concrete 14 .
[0053] During demolition, the anti-corrosion protective layer on the outside of the flange of steel section 12 is removed; longitudinal reinforcement is extended according to the permanent structure, steel sections and studs are welded, stirrups are installed, and concrete is poured.
[0054] Although the above embodiments have described the concepts and embodiments of the present invention in detail with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, so they are not described here one by one.
Claims
1. A steel member protection structure for phased construction of structural columns, used to protect steel members reserved in future structural columns, wherein the steel members extend beyond the top surface of the future structural columns being cast, and characterized by: The steel component protection structure includes a protective cover wrapped around the outer periphery of the steel component, and plastic plate inner formwork is provided on the inner and outer sides of the protective cover. The plastic plate surrounds the steel component as a whole, and a casting protective layer is cast on the inner and outer sides of the plastic plate. The height of the casting protective layer is higher than that of the steel component.
2. The steel component protection structure for phased implementation of structural columns according to claim 1, characterized in that: The bottom of the plastic board inner formwork is embedded in the future structural column to be cast this time.
3. The steel component protection structure for phased implementation of structural columns according to claim 1, characterized in that: The top cover of the cast protective layer is provided with a rainproof protective cover.
4. The steel component protection structure for phased implementation of structural columns according to claim 3, characterized in that: The top of the cast protective layer is pre-embedded with embedded bolts for connecting with the rainproof protective cover, and the cast protective layer is connected to the rainproof protective cover in a detachable bolted manner through the embedded bolts.
5. The steel component protection structure for phased implementation of structural columns according to claim 1 is characterized by: The pouring protection layer is made of low-grade concrete or foam concrete that is easy to remove.
6. The steel component protection structure for phased implementation of structural columns according to claim 1, characterized in that: The protective cover is a polyethylene foam protective cover.
7. The steel component protection structure for phased implementation of structural columns according to claim 1, characterized in that: The steel components are longitudinal reinforcements reserved in the future structural columns of this casting. The heights of the longitudinal reinforcements are different, and the height of the casting protective layer covers all the longitudinal reinforcements.