Post-construction method for cavity layer structure

Abstract

The invention relates to the technical field of building construction, and discloses a cavity layer structure post-construction method which comprises the following steps: S1, after bottom plate construction is completed, construction of a negative first-layer structure is directly carried out; s2, before the negative first-layer wall column formwork is closed, a steel bar reserved opening is formed in the inner side of the formwork; s3, a temporary supporting system for a negative first-layer structure is built; s4, steel bar binding and concrete pouring of wall columns and beam plates of the negative first layer are completed, and the structure is maintained; s5, the formworks and the supports are rearranged after the negative first-layer supporting system is dismantled; and S6, a plurality of holes are reserved in the construction process of the cavity laminate. By adjusting the construction sequence and preferentially constructing the negative first-layer structure, a traditional cavity layer construction process is changed, the negative first-layer structure is completed in advance, connection of the negative first-layer structure and the beam plate reinforcing steel bars of the cavity layer is more accurate, and the effect that the actual clear height of the negative first layer is not affected is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, in particular to a post-construction method for a cavity layer structure. Background Art

[0002] In traditional cavity-level construction, the base slab and cavity-level beams are typically completed first, followed by the basement structure. This sequence often complicates the construction process, and the cavity-level support system must be installed after the basement level is constructed. This not only increases construction time but also potentially affects structural stress and the accuracy of steel connections. During basement level construction, the cavity-level support system often affects the actual net height of the basement level, causing inconvenience in space utilization and construction difficulties.

[0003] In addition, the traditional process of steel bar connection and support system construction usually requires multiple adjustments and coordination between multiple construction links, which can easily lead to inaccurate steel bar connections, extended construction periods, and even affect the stability and force transmission of the final structure. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a post-construction method for a cavity layer structure, which solves the problem that when encountering a cavity layer, the existing technology generally needs to construct the cavity layer structure first, and then set up a formwork frame to construct the upper main structure, and the progress requirements cannot be met in the order during the construction process.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A post-construction method of a cavity layer structure, comprising the following steps: S1: After the basement construction is completed, the construction of the basement structure will be carried out directly; S2: Before closing the wall column formwork on the first floor below ground, a steel bar reservation is set on the inner side of the formwork to embed the steel bars of the cavity layer beam slab inside the wall column and connect and fix them with the wall column reinforcement; S3: Build a temporary support system for the basement structure to support the upper load when the cavity layer is not under construction; S4: Complete the steel bar binding and concrete pouring of the basement wall columns, beams and slabs, and perform structural maintenance; S5: After dismantling the support system of the first basement floor, the formwork and support are rearranged, and the construction of the cavity floor beams and slabs is carried out. The reinforcement of the cavity floor beams and slabs is connected with the embedded reinforcement to complete the structural integrity; S6: During the construction of the cavity laminate, several openings are reserved for material transportation and personnel passage during construction, and are closed after the construction is completed.

[0006] Through the above technical solution: after the base plate construction is completed, the cavity layer structure is not constructed first according to the traditional order, but the basement layer structure is directly constructed. This sequence changed the traditional construction process, ensuring the early completion of the basement structure. Before the basement wall column formwork was closed, rebar reservations were created inside the formwork to embed the rebar for the cavity-level beams and slabs within the wall columns and securely connect them to the wall column reinforcement, ensuring structural continuity between the cavity-level beams and slabs. After the rebar binding of the basement wall columns and beams and slabs was completed, concrete was poured and the structure was cured to ensure the strength and stability of the basement structure. After the basement support system was removed, the formwork and supports were rearranged, and the cavity-level beams and slabs were constructed. The rebar was connected to the embedded rebar to complete the integrity of the cavity-level beams and slabs. During the cavity-level slab construction, several openings were reserved for material transportation and personnel passage during construction. These openings were closed using the formwork after completion. This changed the traditional cavity-level construction process, allowing the basement structure to be completed early and the cavity-level support system to be efficiently constructed. Not only was the rebar connection between the basement structure and the cavity-level beams and slabs more precise, but it also did not affect the actual clear height of the basement.

[0007] Preferably, in S1, after the base plate construction is completed, the underground structure construction is carried out immediately, and pre-embedded steel bars are set. The pre-embedded connection method of the steel bars is completed by mechanical connection. The mechanical connection method includes straight thread sleeve connection, grouting sleeve connection or tapered thread connection, which is used to cooperate with the pre-embedded steel bars during later installation to complete the continuity of the steel bars.

[0008] Through the above technical solution: through the setting of embedded steel bars and mechanical connection methods including straight thread sleeve connection, it can ensure the accuracy of steel bar connection, improve structural continuity and construction efficiency.

[0009] Preferably, in S2, the pre-embedded steel bars are carried out by setting up a special template, and the template design includes inner steel bar fixation and outer steel bar anchoring to determine whether the pre-embedded steel bars are in place. The special template includes a template plate body with a steel bar insertion window, a limiting member for fixing the inserted steel bars, and a sealing device for closing the window after the steel bars are inserted.

[0010] Through the above technical solution: setting up special templates and limiting and sealing structure designs, it can standardize the insertion position of steel bars, ensure the accurate embedding, and improve construction quality and efficiency.

[0011] Preferably, in said S2, the pre-embedding process further includes the following steps: S201, before installing the wall column formwork on the first floor below ground, determine the direction and position of the reinforcement bars for the beam and slab in the cavity layer and preset the reinforcement insertion area; S202: A reserved opening for inserting reinforcement bars is opened at a corresponding position on the inner side of the wall column formwork, and the size of the reserved opening meets the requirements for reinforcement insertion; S203, inserting the cavity layer beam and slab reinforcement into the wall column formwork through the reserved opening and positioning it to the required length; S204, temporarily tying or butting the inserted steel bars with the main reinforcement of the wall column; S205: After completing the steel bar connection, close the template reserved opening and prepare for the subsequent wall column concrete pouring.

[0012] Through the above technical solution: by inserting steel bars into the preset rebar area and template opening and then closing it, it can ensure the precise docking of steel bars, improve the connection reliability and construction convenience. Preferably, in S3, the temporary support system includes a support frame and a support beam, and the support frame is provided with an adjustable height support mechanism according to the construction requirements of the wall columns of the first basement floor, for supporting the cavity layer.

[0013] Through the above technical solution: by combining the support frame and the support beam and setting an adjustable height support mechanism, it can flexibly adapt to the structural size and stably bear the upper load. Preferably, in S4, the maintenance adopts the method of binding wire, limiter, spot welding or template nailing to temporarily fix the inserted embedded steel bars on the wall column reinforcement to prevent displacement or rotation during the concrete pouring process. The concrete pouring adopts fast-setting concrete pouring, and the concrete is vibrated in the wall columns and beams and slabs by a vibrating rod.

[0014] Through the above technical solution: temporarily fixing the steel bars and pouring the quick-setting concrete and vibrating and tamping them by means of binding wires, limiters, spot welds or template nails, the steel bars are ensured to be in a stable position and the concrete is poured densely.

[0015] Preferably, in said S5, after the filled concrete is poured and solidified, dismantling the temporary support system comprises the following steps: S501, start dismantling the temporary support frame, support beam or support system previously erected; S502: After dismantling the support system, a new formwork is erected. The new formwork is used to pour concrete for the cavity layer beam and slab. S503, connecting the cavity layer beam and slab reinforcement to the reinforcement embedded in the wall column by using a straight thread connection; S504, during the connection process, aligning the lap length, connection method, and steel bars of the steel bars; S505, after the connection is completed, the connection part is inspected to check whether the connection between the steel bar and the sleeve is loose and without misalignment; S506, when the steel bar connection is stable, prepare to pour concrete for the subsequent cavity layer beam and slab.

[0016] Through the above technical solution: by removing the temporary support system, installing new formwork and using straight thread to connect the steel bars, it can ensure the stable connection between the cavity layer beam and wall column steel bars and the controllable construction quality. Preferably, the new formwork is positioned and installed according to the size and structural design of the cavity layer beam and slab, and is used to align the connection part between the formwork and the embedded steel bars of the wall column. The straight thread connection is used to thread the ends of the steel bars and connect and fix the steel bars through threaded sleeves. During the connection process, steel bar clamps, positioners or welding methods are used to fix the steel bars.

[0017] Through the above technical solution: by positioning and installing the new template according to the structural dimensions and using straight thread sleeves and auxiliary clamps to fix the steel bars, it can ensure the precise docking of steel bars, improve installation efficiency and connection quality. Preferably, in S6, the opening is arranged to provide a 1 m x 1 m passage every 15 m, and during construction, temporary steel pipes or hanging basket equipment are used for material transportation.

[0018] Through the above technical solution: by laying out passage openings and using temporary steel pipes or hanging basket equipment to transport materials, the construction convenience and material transportation efficiency are improved.

[0019] Preferably, in S6, the hole is closed by hanging formwork after the construction is completed, including the following steps: After the construction of wall columns or beams is completed, clean the area around the reserved openings; After cleaning, install a steel frame or wooden frame around the opening, and then customize the formwork panels according to the inner dimensions of the installed frame. The formwork panels include steel or plywood templates, and preset hanging parts or hook holes on the back of the template; Use a tower crane, construction lifting equipment or manual labor to lift the formwork to the opening position; Align the mark on the opening and slowly lower it, making sure it fits tightly against the bottom edge of the opening. Foam strips and stoppers can be laid between the formwork and the structural surface for sealing. After sealing, the formwork is secured to the structural surface by steel wedges, screws, support rods or through-wall bolts; After the formwork is fixed, concrete sealing construction is carried out at the opening. Fine stone concrete or concrete of the same grade as the original material is used for pouring and vibrating to make it dense.

[0020] Through the above technical solution: by using the hanging formwork method to install the formwork and seal and reinforce it before sealing with concrete, it can ensure that the opening is tightly closed and that the structural integrity and construction safety are taken into account.

[0021] The present invention provides a post-construction method for a cavity layer structure. It has the following beneficial effects: 1. The present invention changes the traditional cavity layer construction process by adjusting the construction sequence and giving priority to the construction of the underground first floor structure. The underground first floor structure is completed in advance. Not only is the connection between the underground first floor structure and the cavity layer beam and slab steel bars more precise, but it also has the effect of not affecting the actual clear height of the underground first floor.

[0022] 2. The present invention sets steel bar reserved openings and combines special templates to carry out pre-embedded steel bar connections. It adopts a mechanical connection method to mechanize the connection between the pre-embedded steel bars and the steel bars of later construction. During use, it achieves good steel bar continuity, reliable connection and simple construction, thereby improving the overall bearing capacity and stability of the structure.

[0023] 3. The present invention optimizes the material transportation path by setting holes at reasonable intervals during the construction process and cooperating with hanging baskets or steel pipe equipment to transport materials, thereby significantly improving construction efficiency and reducing labor costs and operational difficulty during transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a post-construction method of a cavity layer structure according to the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Please see the attached Figure 1 , an embodiment of the present invention provides a cavity layer structure post-construction method, comprising the following steps: S1: After the basement construction is completed, the construction of the basement structure will be carried out directly; S2: Before closing the wall column formwork on the first floor below ground, a steel bar reservation is set on the inner side of the formwork to embed the steel bars of the cavity layer beam slab inside the wall column and connect and fix them with the wall column reinforcement; S3: Build a temporary support system for the basement structure to support the upper load when the cavity layer is not under construction; S4: Complete the steel bar binding and concrete pouring of the basement wall columns, beams and slabs, and perform structural maintenance; S5: After dismantling the support system of the first basement floor, the formwork and support are rearranged, and the construction of the cavity floor beams and slabs is carried out. The reinforcement of the cavity floor beams and slabs is connected with the embedded reinforcement to complete the structural integrity; S6: During the construction of the cavity laminate, several openings are reserved for material transportation and personnel passage during construction, and are closed after the construction is completed.

[0027] In S1, after the base plate construction is completed, the underground structure construction is carried out immediately, and pre-buried steel bars are set. The pre-buried connection method of the steel bars is completed through mechanical connection. The mechanical connection method includes straight thread sleeve connection, grouting sleeve connection or tapered thread connection, which is used to cooperate with the pre-buried steel bars during the later installation to complete the continuity of the steel bars.

[0028] Specifically, after the construction of the foundation slab is completed, the construction process of the underground structure is immediately started. At this stage, by setting up a pre-buried steel bar structure, the connection components required for the subsequent cavity layer beam and slab construction are arranged in advance. The pre-buried steel bars no longer rely on the traditional post-embedded reinforcement process, but are completed simultaneously during the construction of the underground wall columns, effectively improving construction accuracy and reducing the risk of rework in the later stage. At the same time, the pre-buried steel bars are connected to the upper structure by mechanical connection methods, including straight thread sleeve connection, grouting sleeve connection or tapered thread connection. Each connection method is adapted to the interface requirements between different types of components; Among them, the straight thread connection method completes the connection by processing standard threads on the end of the steel bar and tightening it with the matching connecting sleeve. It has the advantages of simple operation and reliable mechanical properties; the grouting sleeve connection is suitable for scenarios where embedded components are difficult to fully emerge, and the embedded connection of the steel bars is achieved by later pouring high-strength non-shrinkage grouting materials; and the tapered thread connection improves the tensile strength and construction tolerance of the connection through a special tapered thread structure. It is particularly suitable for complex node areas with limited space. The traditional post-installation and error-prone steel bar connection process is completed in the construction stage of the first-floor structure, and the standardized component interface ensures the force continuity, reasonable structure and efficient construction between the subsequent cavity layer beams and lower wall columns. It can solve the problems of delayed beam-column connection, incomplete structure, and template interference in the construction of existing cavity systems, and provide structural guarantees for the integrated and modular implementation of layered construction systems. By setting up a mechanically connectable pre-buried steel bar system in the construction of the first-floor structure, efficient docking of subsequent cavity layer components is achieved, and a continuous structural system is formed from bottom to top and layer by layer, which fundamentally improves construction efficiency and structural integrity, and lays the foundation for the implementation of large-volume, rapidly assembled structures.

[0029] In S2, the pre-embedded steel bars are carried out by setting up a special template. The template design includes the fixing of the inner steel bars and the anchoring of the outer steel bars to determine whether the pre-embedded steel bars are in place. The special template includes a template plate with a steel bar insertion window, a limiting component for fixing the inserted steel bars, and a sealing device for closing the window after the steel bars are inserted.

[0030] Specifically, a steel bar insertion window is provided on one side of the formwork plate body, and the window is used to insert the cavity layer beam and slab steel bars into the wall column when the formwork is closed. The size and position of the window are preset in the formwork design stage, and accurately correspond to the position of the embedded steel bars. During the steel bar insertion process, limiting components such as steel bar clamps, positioning rings or guide hole grooves are provided on the inside of the formwork plate body to constrain and control the direction and depth of the inserted steel bars, thereby effectively avoiding deflection, dislocation or out-of-position phenomena during the manual insertion process. At the same time, an identification anchoring device or a positioning stop structure is also provided on the outside of the formwork, which facilitates visual judgment or physical confirmation of the steel bar insertion status during on-site construction, to ensure that each steel bar is indeed in place and reaches the specified anchoring length; After the reinforcement is inserted, the insertion window can be sealed by a sealing device, which is usually a removable plate, a flap structure or a bolt fastener, and the closing operation is completed before the concrete is poured. This design ensures the overall closure of the formwork and the safety of the pouring process, while not destroying the overall stress-bearing performance of the formwork, and is suitable for repeated use and efficient turnover at the construction site. Through the special formwork, an active control mechanism for the guidance and positioning of steel bars is introduced into the formwork. Different from the traditional method that relies solely on manual placement and binding, the position control of the embedded steel bars is more standardized, the structural construction is more controllable, and the docking accuracy of the connecting components and the overall construction efficiency of the structure are improved. This formwork plate not only solves the problems of poor joints and structural stress interruptions caused by steel bar positioning errors, but also creates a precise spatial alignment foundation for subsequent mechanical connections.

[0031] In S2, the pre-embedding process also includes the following steps: S201, before installing the wall column formwork on the first floor below ground, determine the direction and position of the reinforcement bars for the beam and slab in the cavity layer and preset the reinforcement insertion area; S202: A reserved opening for inserting reinforcement bars is opened at a corresponding position on the inner side of the wall column formwork, and the size of the reserved opening meets the requirements for reinforcement insertion; S203, inserting the cavity layer beam and slab reinforcement into the wall column formwork through the reserved opening and positioning it to the required length; S204, temporarily tying or butting the inserted steel bars with the main reinforcement of the wall column; S205: After completing the steel bar connection, close the template reserved opening and prepare for the subsequent wall column concrete pouring.

[0032] Specifically, before the wall and column formwork is installed, the direction and location of the reinforcement bars for the cavity layer beams and slabs are determined in advance. Construction personnel, combining structural design drawings with on-site measurement data, clearly define the wall and column axis, elevation, and spatial orientation corresponding to the inserted bars. This allows the reinforcement insertion area to be locked in during the initial stages of structural construction, eliminating the uncertainty of "blind insertion" of reinforcement bars after the formwork has been installed, and achieving a high degree of geometric matching between the embedded components and the structural system. Next, a reserved opening for rebar insertion is created at a specific location inside the wall column formwork. The size of this opening is calculated based on the diameter of the inserted rebar, positioning tolerance, and operating space, and is completed during the formwork processing stage. The provision of the reserved opening not only ensures smooth insertion of the rebar but also provides ease of operation for construction personnel, enhancing the formwork system's ability to accommodate and control the behavior of rebar insertion. Subsequently, the cavity layer beam and slab reinforcement is inserted into the formwork through the aforementioned reserved openings and secured at the preset depth using positioning marks or limiting components. The reinforcement insertion process, combined with the formwork's built-in limiting devices and external visual aids, provides clear operational feedback, allowing construction personnel to confirm whether the reinforcement is fully in place, in the correct direction, and at the required depth. This step significantly improves the reliability and standardization of pre-embedded reinforcement. After the reinforcement is inserted, further preparations are made for temporary binding or docking with the main reinforcement of the wall column. Depending on the subsequent connection method, initial fixation can be achieved using methods such as binding wire, positioning frames, and pre-installed sleeves to avoid positional shifting or connection failure during construction. Finally, after the reinforcement is inserted and connected, the formwork opening is sealed with a removable cover, sliding cover, or spiral lock to restore the overall sealing properties of the formwork. This process not only ensures the safety of subsequent concrete pouring and the integrity of the formwork support, but also achieves an organic combination of the reinforcement insertion function and the formwork sealing performance, providing conditions for the formation of high-quality wall column structures.

[0033] In S3, the temporary support system includes a support frame and a support beam, and the support frame is provided with an adjustable height support mechanism according to the construction requirements of the wall columns of the first floor below ground level to support the cavity layer.

[0034] Specifically, support beams are arranged horizontally between multiple support frames to support the wall column formwork, embedded steel bar formwork, and some construction loads. They are securely connected to the support frames via bolts, slots, or welding, forming a high-strength, stable framework support structure. The support beams can be flexibly positioned based on the formwork distribution to effectively transmit structural reaction forces. This temporary support system provides reliable support for the basement wall columns and beam-slab structure even before the cavity layer is constructed and the lower structure lacks permanent load-bearing components. Furthermore, the adjustable height of the support frames meets the precise construction requirements for elevation control and formwork joint alignment for different structural components in complex sites.

[0035] In S4, the embedded steel bars are temporarily fixed to the wall column reinforcement by means of binding wires, limiters, spot welds or formwork nails to prevent displacement or rotation during the concrete pouring process. The concrete is poured using fast-setting concrete, and the concrete is vibrated in the wall columns and beams and slabs by means of vibrating rods.

[0036] Specifically, the reinforcement and the original main reinforcement of the wall column can be mechanically limited and fixed by various means such as binding with wire, embedding with limiters, short spot welding connection or positioning with formwork nails. Binding wire is used to achieve local bundling through manual quick wrapping, which is suitable for conventional reinforcement; the limiter can be a prefabricated plastic clip or steel clip, which is used to lock the space between reinforcements; and spot welding parts are suitable for reinforcement welding areas with construction conditions to achieve short-range rigid connection between reinforcements; for the reinforcement insertion end close to the formwork surface, the formwork reinforcement can also be integrated with the formwork reinforcement by inserting positioning nails through the formwork opening, which effectively prevents the reinforcement from axial sliding, lateral displacement or angular torsion due to vibration, impact or concrete flow during concrete pouring, ensuring that the inserted reinforcement is always in the spatial position specified by the design, thereby ensuring the geometric accuracy and structural performance of the subsequent mechanical connection; After the formwork is sealed, concrete pouring for the walls, columns, beams, and slabs begins. During the pouring process, vibrators are used to vibrate the concrete within the formwork layer by layer, focusing on increasing the density of the concrete in areas with dense reinforcement and at rebar joints. The sequence, insertion depth, and spacing of the vibrators are carefully tailored to the distribution of reinforcement and the formwork shape, ensuring continuous, dense concrete, free of voids and honeycombing, within the transition areas between the walls, columns, and beams.

[0037] In S5, after the filling concrete is poured and solidified, the temporary support system is dismantled, including the following steps: S501, start dismantling the temporary support frame, support beam or support system previously erected; S502: After dismantling the support system, a new formwork is erected. The new formwork is used to pour concrete for the cavity layer beam and slab. S503, connecting the cavity layer beam and slab reinforcement to the reinforcement embedded in the wall column by using a straight thread connection; S504, during the connection process, aligning the lap length, connection method, and steel bars of the steel bars; S505, after the connection is completed, the connection part is inspected to check whether the connection between the steel bar and the sleeve is loose and without misalignment; S506, when the steel bar connection is stable, prepare to pour concrete for the subsequent cavity layer beam and slab.

[0038] Specifically, after the infill concrete has completely solidified, the temporary support system will be dismantled first, including the phased and layered removal of the supporting structures such as the support frames and beams erected earlier. To prevent sudden unloading of the structure, the dismantling process follows the principle of removing the secondary first, then the primary, and the outer ring first, then the core. After the support system is completely dismantled, a new formwork is erected. This formwork is installed around the cavity layer beam and slab area, and is responsible for the subsequent concrete forming and steel bar connection positioning functions. The formwork structure is arranged according to the direction of the pre-embedded steel bar interface, and space for steel bar connection operations is reserved to facilitate subsequent plug-in and operation.

[0039] The steel bar connection adopts the straight thread connection method, that is, the connection is completed by screwing the end threads of the cavity layer beam and slab steel bars and the embedded steel bars in the wall columns with the standard sleeve connector. The straight thread connection has the characteristics of high tensile strength and high degree of standardization of construction operations. It is a mature solution for current force-type connections. In this way, the upper beam and slab steel bars and the lower embedded bars are accurately connected, providing a guarantee for the continuous transmission of structural force. During the connection process, the lap length, connection method and axis alignment of the steel bars are especially checked. The steel bar connection must strictly comply with the design specification requirements and no eccentricity, short circuit or misalignment shall occur. To this end, physical limiters, positioning scales or sleeve locking torque control devices can be used to ensure the high consistency of the steel bars in the spatial direction and mechanical path; After the connection is complete, a comprehensive inspection of the connection is immediately conducted, including the length of the sleeve thread engagement, whether the connection is loose, and whether there is any lateral misalignment. The inspection process can be supplemented by visual inspection, test tightening with tools, and positioning calipers to achieve standardized acceptance. Once all connection nodes are confirmed to be stable and meet the structural acceptance standards, the concrete pouring of the cavity layer beam and slab can be prepared. This stage of construction will complete the formation and sealing of the beam and slab structure and further anchor the previously inserted reinforcement system into the structure, forming a complete load-bearing system for the upper and lower components.

[0040] The new formwork is positioned and installed according to the size and structural design of the cavity layer beam and slab. It is used to align the connection part between the formwork and the embedded steel bars of the wall column. The straight thread connection is used to thread the ends of the steel bars and fix the steel bars through threaded sleeves. During the connection process, steel bar clamps, positioners or welding methods are used to fix the steel bars.

[0041] Specifically, the new formwork system, installed after the temporary support system was removed, not only takes on the task of concrete forming but also assists in rebar positioning. This formwork is fabricated based on the structural dimensions, beam width, beam height, and spatial arrangement of the embedded rebar in the cavity layer beam slab. During installation, three-dimensional positioning is performed using elevation control points, structural axes, and rebar interface points to ensure that the formwork edges and positioning holes are axially aligned and positionally aligned with the embedded rebar in the lower wall studs. The connection area between the formwork and the wall studs is pre-installed with rebar guide holes or observation windows during the formwork design phase. This allows the rebar inserted into the cavity layer beam slab to smoothly pass through the formwork and dock with the embedded rebar during the connection process, avoiding connection difficulties or error accumulation caused by formwork obstruction.

[0042] The steel bar connection adopts a straight thread mechanical connection method, that is, the ends of the steel bars are subjected to thread rolling or cutting to form standard straight thread ends; then they are screwed together through a matching standard threaded connection sleeve to achieve axial connection and mechanical property transfer of the steel bars. During the steel bar docking process, in order to further improve the connection accuracy and stability, auxiliary positioning devices including steel bar clamps, limiters or temporary welds are used. The steel bar clamp is used to clamp the steel bars at both ends and force them to align; the limiter can limit the axial slippage or deflection of the steel bars during the screwing process; if construction conditions permit, the steel bars can also be spot welded to form a temporary rigid connection, thereby maintaining the stability of the connection interface during the sleeve screwing process. Through the above control measures, it is ensured that the ends of the steel bars are centered and the threaded connection is not loose, laying the foundation for the subsequent beam and slab casting and the stress of the overall structure.

[0043] In S6, the opening is set up as a 1m×1m passage every 15m, and during construction, temporary steel pipes or hanging basket equipment are used for material transportation.

[0044] Specifically, during construction, tunnel openings are used in conjunction with temporary steel pipe supports or suspended basket transport equipment to facilitate the targeted transport of materials from the lower working level to the interior of the cavity. Steel pipe supports can be used to create platforms, inclined ladders, or cantilevered supports, forming material slides or manual handling paths that span multiple levels. Suspended basket equipment is primarily used for vertically lifting heavy materials, steel components, or equipment, often operated via a hoist or winch, and combined with guide rails and limiters to ensure safe and stable transportation.

[0045] In S6, the opening is closed by hanging formwork after construction is completed, including the following steps: After the construction of wall columns or beams is completed, clean the area around the reserved openings; After cleaning, install a steel frame or wooden frame around the opening, and then customize the formwork panels according to the inner dimensions of the installed frame. The formwork panels include steel or plywood templates, and preset hanging parts or hook holes on the back of the template; Use a tower crane, construction lifting equipment or manual labor to lift the formwork to the opening position; Align the mark on the opening and slowly lower it, making sure it fits tightly against the bottom edge of the opening. Foam strips and stoppers can be laid between the formwork and the structural surface for sealing. After sealing, the formwork is secured to the structural surface by steel wedges, screws, support rods or through-wall bolts; After the formwork is fixed, concrete sealing construction is carried out at the opening. Fine stone concrete or concrete of the same grade as the original material is used for pouring and vibrating to make it dense.

[0046] Specifically, first, after the concrete construction of the wall column or beam slab is completed and reaches a certain strength, the area around the previously preset passage opening is thoroughly cleaned, including removing slurry, oil stains, residues and loose concrete blocks, to provide a clean, dry and bondable structural interface for formwork sealing; After cleaning, install a steel frame or wooden frame on the structural surface around the opening to form a template installation guide and support structure. Customize the template panels according to the inner dimensions of the installation frame. The template can be a steel template or a plywood template. The back of the template is preset with hanging parts, rings or hook holes to facilitate the lifting equipment to safely lift and position the template. After the template is completed, the template panels are hoisted above the opening by a tower crane, construction lifting equipment or manual handling, and slowly lowered and aligned with the positioning mark. During the contact between the template and the structural surface of the opening, foam strips, grouting tapes, sealants and other materials are set between the joints to form an effective sealing layer to prevent mortar leakage during subsequent pouring; After the formwork is aligned with the structural surface of the opening, temporary fixings such as steel wedges, screws, support rods, or through-wall bolts are used to securely fasten the formwork to the structural surface. Fixing devices should be strategically positioned according to the formwork's position and opening dimensions to ensure uniform stress distribution, prevent warping or displacement, and create a stable forming space for subsequent concrete sealing. Once the formwork is stabilized, concrete sealing of the opening can begin. Fine aggregate concrete or high-strength commercial concrete of the same grade as the original component should be preferred, mixed according to the specified proportions. During pouring, vibrate the concrete appropriately with an inserted vibrator to ensure that the concrete fills the formwork space and is free of hollows or honeycombing. After initial setting, the surface layer is leveled and cured. The reserved ends of the beams need to be threaded for later use as straight-thread connections. Use a Grade 1 straight-thread sleeve. The reserved beam-slab bottom reinforcement should be left at a span ratio of (1:4) to (1:3). Joints between adjacent longitudinal tension bars within the same component must be staggered.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A post-construction method for a cavity layer structure, characterized in that: The following steps are involved: S1: After the basement construction is completed, the construction of the basement structure will be carried out directly; S2: Before closing the wall column formwork on the first floor below ground, a steel bar reservation is set on the inner side of the formwork to embed the steel bars of the cavity layer beam slab inside the wall column and connect and fix them with the wall column reinforcement. S3: Build a temporary support system for the basement structure to support the upper load when the cavity layer is not under construction; S4: Complete the steel bar binding and concrete pouring of the basement wall columns, beams and slabs, and perform structural maintenance; S5: After dismantling the support system of the first basement floor, the formwork and support are rearranged, and the construction of the cavity floor beams and slabs is carried out. The reinforcement of the cavity floor beams and slabs is connected with the embedded reinforcement to complete the structural integrity; S6: During the construction of the cavity laminate, several openings are reserved for material transportation and personnel passage during construction, and are closed after the construction is completed.

2. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In S1, after the base plate construction is completed, the underground structure construction is carried out immediately, and pre-embedded steel bars are set. The pre-embedded connection method of the steel bars is completed by mechanical connection. The mechanical connection method includes straight thread sleeve connection, grouting sleeve connection or tapered thread connection, which is used to cooperate with the pre-embedded steel bars during later installation to complete the continuity of the steel bars.

3. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In S2, the pre-embedded steel bars are carried out by setting up a special template. The template design includes fixing the inner steel bars and anchoring the outer steel bars to determine whether the pre-embedded steel bars are in place. The special template includes a template plate body with a steel bar insertion window, a limiting member for fixing the inserted steel bars, and a sealing device for closing the window after the steel bars are inserted.

4. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In said S2, the pre-embedding process further includes the following steps: S201, before installing the wall column formwork on the first floor below ground, determine the direction and position of the reinforcement bars for the beam and slab in the cavity layer and preset the reinforcement insertion area; S202: A reserved opening for inserting reinforcement bars is opened at a corresponding position on the inner side of the wall column formwork, and the size of the reserved opening meets the requirements for reinforcement insertion; S203, inserting the cavity layer beam and slab reinforcement into the wall column formwork through the reserved opening and positioning it to the required length; S204, temporarily tying or butting the inserted steel bars with the main reinforcement of the wall column; S205: After completing the steel bar connection, close the template reserved opening and prepare for the subsequent wall column concrete pouring.

5. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In S3, the temporary support system includes a support frame and a support beam, and the support frame is provided with an adjustable height support mechanism according to the construction requirements of the wall columns of the first underground floor, so as to support the cavity layer.

6. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In said S4, the embedded steel bars are temporarily fixed to the wall column reinforcement by means of binding wires, limiters, spot welds or template nails, so as to prevent displacement or rotation during the concrete pouring process. The concrete pouring adopts fast-setting concrete pouring, and the concrete is vibrated in the wall columns and beams and slabs by means of a vibrating rod.

7. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In said S5, after the filled concrete is poured and solidified, dismantling the temporary support system includes the following steps: S501, start dismantling the temporary support frame, support beam or support system previously erected; S502: After dismantling the support system, a new formwork is erected. The new formwork is used to pour concrete for the cavity layer beam and slab. S503, connecting the cavity layer beam and slab reinforcement to the reinforcement embedded in the wall column by using a straight thread connection; S504, during the connection process, aligning the lap length, connection method, and steel bars of the steel bars; S505, after the connection is completed, the connection part is inspected to check whether the connection between the steel bar and the sleeve is loose and without misalignment; S506, when the steel bar connection is stable, prepare to pour concrete for the subsequent cavity layer beam and slab.

8. The post-construction method of a cavity layer structure according to claim 7, characterized in that: The new template is positioned and installed according to the size and structural design of the cavity layer beam and slab, and is used to align the template with the embedded steel bar connection part of the wall column. The straight thread connection is used to thread the end of the steel bar and connect and fix the steel bar through a threaded sleeve. During the connection process, the steel bar is fixed by a steel bar clamp, a positioner or welding means.

9. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In the S6, the opening is set to set a 1 meter × 1 meter channel every 15 meters, and during the construction period, temporary steel pipes or hanging basket equipment are used for material transportation.

10. The post-construction method of a cavity layer structure according to claim 1, characterized in that: In S6, the opening is closed by hanging formwork after the construction is completed, including the following steps: After the construction of wall columns or beams is completed, clean the area around the reserved openings; After cleaning, install a steel frame or wooden frame around the opening, and then customize the formwork panels according to the inner dimensions of the installed frame. The formwork panels include steel or plywood templates, and preset hanging parts or hook holes on the back of the template; Use a tower crane, construction lifting equipment or manual labor to lift the formwork to the opening position; Align the mark on the opening and slowly lower it, making sure it fits tightly against the bottom edge of the opening. Foam strips and stoppers can be laid between the formwork and the structural surface for sealing. After sealing, the formwork is secured to the structural surface by steel wedges, screws, support rods or through-wall bolts; After the formwork is fixed, concrete sealing construction is carried out at the opening. Fine stone concrete or concrete of the same grade as the original material is used for pouring and vibrating to make it dense.

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