A prefabricated assembly type steel reinforced concrete rectangular composite column with removable formwork

Abstract

The utility model discloses a kind of prefabricated assembly type steel concrete rectangular composite columns of exempt from dismantling mould, including peripheral formwork and H-shaped steel, H-shaped steel is set along the axial direction of peripheral formwork when using, and fixed in the cavity central axis of peripheral formwork, the gap of H-shaped steel and peripheral formwork is the pouring space of cast-in-place concrete;Wherein, the stainless steel tube of peripheral formwork is arranged at the outermost side, PBL board is spaced apart and arranged on the inner surface of stainless steel tube, steel reinforcement cage is fixed on the inner surface of stainless steel tube, and is formed by using ultra-high performance concrete pouring molding, forms hollow peripheral formwork;H-shaped steel plate with hole is arranged at the both ends of peripheral formwork.The utility model provides a kind of prefabricated assembly type steel concrete rectangular composite columns of exempt from dismantling mould, and its peripheral formwork connection realizes full prefabricated assembly technology, with high continuous reliability, high durability, with excellent environmental protection performance, excellent anti-seismic performance and high node rigidity, simultaneously with high economic performance.

Description

Technical Field

[0001] This utility model relates to the field of building technology, and in particular to a prefabricated steel-concrete rectangular composite column that does not require demolding. Background Technology

[0002] In existing technologies, column-to-column connections in precast steel frames often employ high-strength bolts or welded joints, effectively transferring axial force, bending moment, and shear force to meet structural load continuity requirements. However, the design of connection joints in precast concrete formwork, a key component for external constraint and lateral force resistance, is often overlooked. Currently, the common practice is to treat the formwork as a non-load-bearing component, using post-cast concrete or simple splicing methods, leading to the following problems: 1) Insufficient collaborative performance between the formwork and steel frame, weakening the overall stiffness and seismic energy dissipation capacity of the composite column; 2) Additional formwork and concrete pouring in the joint area are required on-site, increasing construction steps and affecting assembly efficiency; 3) Cracks easily form at the interface between the post-cast area and the precast formwork, affecting structural durability.

[0003] In the field of prefabricated building structures, the performance of joint connections directly determines the overall structure's load-bearing capacity, seismic performance, and construction efficiency. Currently, traditional prefabricated concrete structure joints mostly adopt wet connections (such as cast-in-place concrete post-pouring strips, grouting sleeves, etc.), which, while achieving a certain degree of integrity, still have the following problems:

[0004] 1) Low construction efficiency: Wet connection requires on-site formwork, pouring and curing, which is complicated, prolongs the construction period, and is subject to environmental conditions, resulting in increased construction costs and difficulty in ensuring construction quality under multiple processes, resulting in the overall performance of the joint being worse than expected.

[0005] 2) Insufficient connection reliability: In areas with dense reinforcement, problems such as incomplete grouting and sleeve misalignment are prone to occur, causing the nodes to become weak links in the structure, resulting in connection quality problems and making it difficult to guarantee the overall structure integrity;

[0006] 3) High transportation and hoisting costs: Traditional precast concrete components are heavy, making transportation and hoisting difficult and economical.

[0007] 4) Durability defects: Ordinary formwork is prone to rust, and the concrete surface needs to be treated again after demolding. In the long term, the joint area is prone to leakage or corrosion, which affects its performance.

[0008] 5) Insufficient environmental protection: Wet construction generates a large amount of construction waste, wastewater and carbon emissions, which does not conform to the concept of green building.

[0009] While dry connection technologies (such as bolted connections and welding) simplify construction, the stiffness of dry connection joints is generally lower than that of cast-in-place joints, making them prone to deformation, especially under cyclic loading (such as earthquakes), leading to a decrease in overall structural integrity. Insufficient interfacial bond between steel and concrete may cause stress redistribution, reducing load-bearing capacity. Stress concentration is prone to occur at connection points (such as bolt holes and welds), which may lead to fatigue cracks under long-term or dynamic loads, affecting durability. The ductility of dry connection joints is generally lower than that of cast-in-place joints, making it difficult to dissipate energy through plastic deformation during earthquakes, potentially leading to brittle failure. Loosening of bolted connections or cracking of welds will further weaken seismic performance. Summary of the Invention

[0010] In view of the aforementioned deficiencies in the prior art, the technical problem to be solved by this utility model is the existence of problems such as weak continuous reliability, low durability, poor environmental performance, and low joint stiffness in precast assembled steel-concrete composite columns. This utility model provides a precast assembled steel-concrete rectangular composite column without formwork removal, featuring dry-wet mixed joints. Its outer formwork connection realizes fully precast assembly technology, exhibiting high continuous reliability, high durability, excellent environmental performance, excellent seismic performance, and high joint stiffness, while also possessing high economic performance.

[0011] To achieve the above objectives, this utility model provides a precast assembled steel-concrete rectangular composite column that does not require demolding, including an outer mold shell and H-beams. In use, the H-beams are arranged along the axial direction of the outer mold shell and fixed to the central axis of the cavity of the outer mold shell. The gap between the H-beams and the outer mold shell is the pouring space for cast-in-place concrete.

[0012] The outer formwork includes stainless steel pipes, ultra-high performance concrete, a reinforcing cage, a U-shaped perforated steel plate, and PBL plates. The stainless steel pipes are placed on the outermost side, and the PBL plates are spaced apart on the inner surface of the stainless steel pipes. The reinforcing cage is fixed to the inner surface of the stainless steel pipes and is cast using ultra-high performance concrete to form a hollow outer formwork. The U-shaped perforated steel plate is placed at both ends of the outer formwork.

[0013] Furthermore, the outer shell is designed as a hollow column structure with a rectangular cross-section, and both its outer and inner walls are planar.

[0014] Furthermore, the reinforcing cage includes a number of main bars extending axially along the stainless steel pipe, and closed stirrups surrounding the main bars.

[0015] Furthermore, closed stirrups include either ring stirrups or continuous spiral stirrups.

[0016] Furthermore, the length of the H-beam is greater than the length of the outer mold shell.

[0017] Furthermore, the outer edge of the U-shaped perforated steel plate is flush with the stainless steel pipe, and the inner edge is flush with the inner edge of the high-performance concrete. The U-shaped perforated steel plate is fixedly connected to the main reinforcement.

[0018] Furthermore, the perforated steel plate in the shape of a square has pre-reserved holes.

[0019] Furthermore, each of the four edges of the U-shaped perforated steel plate has three reserved holes.

[0020] Furthermore, pre-drilled bolt holes are provided at both ends of the H-beam.

[0021] Technical effect

[0022] This utility model provides a precast, modular, assembled steel-concrete rectangular composite column that requires no formwork removal. The column, composed of stainless steel pipes, ultra-high-performance concrete, H-beams, and cast-in-place concrete, is connected by perforated steel plates, high-strength steel plates, and bolts to form a novel composite column connection node. This connection node is a hybrid dry-wet node, and the outer formwork connection achieves fully precast assembly technology. Through precision factory manufacturing and modular on-site assembly, the internal concrete is poured monolithically. Details are as follows:

[0023] 1) High connection reliability: The integrated precast formwork is seamlessly spliced ​​with adjacent formwork through connectors, forming a continuous closed constraint on the concrete in the joint area, which improves the integrity of the prefabricated composite column. It realizes the integration of formwork function and structural performance.

[0024] 2) Good economic efficiency: Lightweight component design reduces transportation and hoisting costs.

[0025] 3) High durability: The no-removal-formwork design and high-performance concrete shell reduce the risk of leakage and corrosion.

[0026] 4) Excellent environmental performance: Reduces wet work, reduces construction waste and carbon emissions, and conforms to the concept of green building.

[0027] 5) High node stiffness: The wet connection enhances the node stiffness while maintaining the construction convenience of the dry connection, significantly improving the bending and shear stiffness of the node area.

[0028] 6) Excellent seismic performance: The wet connection in this patented joint design effectively transmits internal forces, enhancing the integrity and deformation capacity of the joint, thus providing higher ductility and energy dissipation capacity. The high-strength bolts in the dry connection possess rigid connection characteristics. This combination of designs allows the joint to concentrate and dissipate energy under seismic loads while maintaining the integrity of the main structure, preventing premature entry into the plastic stage, thereby significantly improving the structure's seismic performance.

[0029] This utility model provides a prefabricated, formwork-free, assembled steel-concrete rectangular composite column, which integrates the high strength of the steel frame, the durability of concrete, and the high efficiency of prefabrication technology, offering significant technical advantages. The H-beams and outer formwork are prefabricated as a single unit in the factory. Standardized production achieves high dimensional accuracy, controllable quality, and short on-site construction cycles, while also reducing on-site wet work, aligning with the development trends of green building and industrialized construction. It can be widely used in high-rise buildings, long-span bridges, industrial plants, and underground space engineering, demonstrating significant competitiveness, especially in scenarios requiring rapid construction or high seismic performance.

[0030] The following will further explain the concept, specific structure and technical effects of this utility model in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of this utility model. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the outer mold shell of a precast steel-concrete rectangular composite column that does not require demolding, according to a preferred embodiment of this utility model.

[0032] Figure 2 This is a cross-sectional structural diagram of the outer mold shell of a precast assembled steel-concrete rectangular composite column that does not require demolding, according to a preferred embodiment of this utility model.

[0033] Figure 3 yes Figure 2 A schematic diagram of the AA section along the central axis;

[0034] Figure 4 yes Figure 2 A schematic diagram of the BB cross-section along the central axis;

[0035] Figure 5 This is a schematic diagram of the CC cross-section along the central axis.

[0036] Figure 6 This is a cross-sectional structural schematic diagram of a prefabricated steel-concrete rectangular composite column that does not require demolding, according to a preferred embodiment of this utility model.

[0037] Figure 7 yes Figure 6 A schematic diagram of the AA section along the central axis;

[0038] Figure 8 This is a schematic diagram of the node steel connection of a precast steel-concrete rectangular composite column without demolding, according to a preferred embodiment of this utility model.

[0039] Figure 9This is a schematic diagram of the node formwork connection of a precast steel-concrete rectangular composite column without formwork removal, according to a preferred embodiment of this utility model.

[0040] Figure 10 This is a schematic diagram of the completed mold shell connection of a precast assembled steel-concrete rectangular composite column without demolding, according to a preferred embodiment of this utility model.

[0041] Figure 11 This is a schematic diagram of the overall connection of a precast steel-concrete rectangular composite column without demolding, according to a preferred embodiment of this utility model.

[0042] Figure 12 This is a schematic diagram of pouring UHPC concrete into the cavity of a precast steel-concrete rectangular composite column without demolding, which is a preferred embodiment of this utility model.

[0043] Among them, 1. Stainless steel pipe; 2. Reinforcing cage; 3. Ordinary concrete; 4. Concrete reserved cavity; 5. H-beam; 6. PBL plate; 7. Ultra-high performance concrete; 8. Perforated steel plate with a U-shape. Detailed Implementation

[0044] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0045] like Figure 1-7 As shown, this utility model provides a precast assembled steel-concrete rectangular composite column that does not require demolding, including an outer mold shell and H-beams. When in use, the H-beams are arranged along the axial direction of the outer mold shell and fixed to the central axis of the cavity of the outer mold shell. The gap between the H-beams and the outer mold shell is the pouring space for cast-in-place concrete.

[0046] The outer formwork comprises stainless steel pipe 1, ultra-high performance concrete (UHPC) 7, reinforcing cage 2, UHPC-shaped perforated steel plate 8, and PBL plate 6. Stainless steel pipe 1 is positioned on the outermost side, and PBL plates 6 are spaced apart on the inner surface of stainless steel pipe 1. The reinforcing cage 2 is fixed to the inner surface of stainless steel pipe 1 and cast using UHPC 7 to form a hollow outer formwork. The UHPC-shaped perforated steel plate 8 is positioned at both ends of the outer formwork. One short side of the PBL plate is welded to the stainless steel pipe, while the other three sides are encased in UHPC. The PBL plate interlocks with the concrete through openings in the steel plate, efficiently transferring interfacial shear force, ensuring that the steel and concrete share the load, and reducing the risk of slippage. Ultra-high performance concrete (UHPC) has a compressive strength ≥120MPa and a flexural strength ≥20MPa. The composite formwork composed of UHPC and the outer stainless steel pipe 2 combines high strength with synergistic ductility enhancement.

[0047] The outer shell is designed as a rectangular cross-section hollow column structure, with both its outer and inner walls being planar.

[0048] The reinforcing cage 2 includes a number of main reinforcing bars extending axially along the stainless steel pipe, and closed stirrups surrounding the main reinforcing bars. The closed stirrups include either ring stirrups or continuous spiral stirrups.

[0049] The length of H-beam 5 is greater than the length of the outer mold shell. Pre-drilled bolt holes are provided at both ends of the H-beam.

[0050] The outer edge of the U-shaped perforated steel plate 8 is flush with the stainless steel pipe, and the inner edge is flush with the inner edge of the high-performance concrete. The U-shaped perforated steel plate is fixedly connected to the main reinforcement. The U-shaped perforated steel plate is provided with reserved holes. Specifically, there are 3 reserved holes on each of the four edges of the U-shaped perforated steel plate.

[0051] This utility model discloses a precast, assembled steel-concrete rectangular composite column that requires no formwork removal. In use, it employs a step-by-step construction method: "positioning of H-beams 5 → assembly of the outer formwork → concrete pouring," fully leveraging the synergistic effect of prefabrication and cast-in-place construction. The prefabrication of the outer formwork ensures the precise shaping of the high-performance outer materials, while the on-site pouring of C50 concrete 3 ensures a tight bond between the core area and the H-beams 5, eliminating interface defects.

[0052] The following will describe in detail the prefabrication and cast-in-place steps of a precast assembled steel-concrete rectangular composite column without formwork removal according to this utility model.

[0053] S1: Prefabricate a high-performance peripheral mold shell in the factory. The specific steps are as follows:

[0054] 1) Cut two L-shaped stainless steel parts according to the design dimensions, and cut off the corresponding hole area of ​​the U-shaped perforated steel plate so that the U-shaped perforated end plate can be opened with reserved holes.

[0055] 2) Weld PBL plates 6 at equal intervals along the inner wall of the L-shaped part.

[0056] 3) Weld two L-shaped parts to form a stainless steel pipe 1.

[0057] 4) Position welding of one end of the U-shaped perforated steel plate 8, the reinforcing cage 2, and the stainless steel pipe 1.

[0058] 5) Using stainless steel pipe 1 as the external template, after installing the cavity template, pour ultra-high performance concrete (UHPC), cure and demold to form a composite mold shell with a U-shaped perforated steel plate 8 and a reserved cavity 4. Weld the other end of the U-shaped perforated steel plate 8 to form a hollow outer mold shell. During the pouring of UHPC, the template is installed at the position of the reserved cavity 4. The reserved cavity 4 is a working space reserved when tightening the U-shaped perforated end plate with bolts.

[0059] S2: On-site casting of precast, assembled, formwork-free precast steel-concrete rectangular composite columns, the specific steps are as follows:

[0060] 1) The H-beam 5 is precisely fixed using a positioning device, and the sleeve installation of the outer mold shell is completed simultaneously, strictly controlling the design gap value between the inner wall of the mold shell and the main body of the H-beam 5;

[0061] 2) Implement ordinary concrete layered pouring process, and after curing and hardening, form a prefabricated assembled steel-concrete rectangular composite column structure system with stainless steel-UHPC composite formwork.

[0062] like Figure 8-12 As shown below, the connection construction method of prefabricated steel-concrete rectangular composite columns that do not require formwork removal will be explained in detail below.

[0063] S1: Construction of precast steel-concrete composite rectangular columns without formwork removal, the specific steps are as follows:

[0064] 1) At the construction site, locate the lower layer of Q345B grade H-beams 5 according to the design drawings, and use a temporary support system to fix the H-beams to the foundation or existing structure. During positioning, use measuring instruments to calibrate the position to ensure that the verticality and flatness of the H-beams meet the requirements, and check the installation accuracy after fixing.

[0065] 2) Hoist the lower precast stainless steel-UHPC mold shell and fit it onto the outside of the H-beam (5). Adjust the position of the mold shell during installation to ensure that the ends of the steel section (5) and the connecting holes are fully exposed. After completion, check and adjust the fitting gap to meet the design requirements.

[0066] The gap should meet the requirements for concrete compaction, and is generally not less than 30-50mm (adjusted according to aggregate size, and should be greater than 1.5 times the maximum aggregate size). The gap should allow for the insertion of vibratory equipment (e.g., vibrator diameter is typically 50-80mm), and a gap of ≥80mm is recommended to ensure sufficient vibration. The thickness of the concrete protective layer from the inner side of the formwork to the surface of the H-beam should meet the requirements for corrosion and fire protection: General environment: ≥30mm (refer to GB 50936 "Technical Specification for Steel Pipe Concrete Structures"). Corrosive environment: ≥50mm, or compensated for by additional anti-corrosion measures (e.g., coating).

[0067] 3) Position the upper layer of Q345B grade H-beam 5. The upper and lower layers of H-beam 5 are joined by end plates (end plates refer to a rigid connection method using perforated steel plates and bolts). Pre-drill bolt holes at the flange and web ends of the H-beam according to the specified spacing (≥3d). Use Q355B steel plates as connecting plates, with their hole positions matching the hole groups of the H-beams. Install 10.9 grade M24 high-strength bolts using the pre-drilled bolt holes for mechanical connection. During installation, ensure the end plates fit tightly, tighten the bolts sequentially step by step, and check the tightness of the connection joints after completion.

[0068] 4) Hoist the upper precast stainless steel-UHPC formwork shell. The outer formwork shell is bolted together using Q345B grade U-shaped perforated steel plates (bolted together through pre-reserved cavities). The joints are sealed by welding. Clean the contact surfaces before welding, weld continuously to ensure full welds, and treat spatter and check the sealing performance after welding.

[0069] 5) Pour UHPC grout into the outer mold cavity, controlling the flow rate to remove air during grouting. After grouting, seal the grouting hole by welding a stainless steel pipe to ensure the cavity is completely filled.

[0070] 6) After the column-to-column connection is completed, C50 grout is injected into the gap between the upper formwork of the composite column and the H-beam 5. During concrete pouring, a continuous and uniform construction rhythm should be maintained to avoid interruptions or localized accumulation. During pouring, specialized equipment should be used to fully fill the gap between the outer formwork and the H-beam 5 with concrete, ensuring the poured surface is flush with the top of the outer formwork. Immediately after pouring, a vibratory compactor should be used to thoroughly vibrate the concrete, eliminating internal air bubbles and voids, and improving density. Curing should begin after the concrete has set. The surface should be kept moist by regularly sprinkling water or covering it with a moisture-retaining material. The curing period should be no less than 28 days to prevent shrinkage cracks.

[0071] 7) Inspection and acceptance after construction must ensure the structural installation accuracy, verticality of upper and lower H-beams ≤ 1 / 1000, end plate gap ≤ 0.5mm, connection node quality, M24 bolt torque 900~1100N·m, welds without leakage and qualified ultrasonic testing, and the compactness of the formwork and UHPC / C50 concrete pouring (cavity rate ≤ 0.5%, concrete strength ≥ 115% of design value). Material certificates, construction records and third-party testing reports must be verified. After passing load tests and corrosion tests, acceptance is only possible if 100% of key items are qualified and the overall qualification rate is ≥ 95%. Local defects must be rectified and re-inspected for confirmation.

[0072] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A precast, assembled steel-concrete rectangular composite column that requires no formwork removal, characterized in that, It includes a peripheral formwork and an H-shaped steel. During use, the H-shaped steel is arranged along the axial direction of the peripheral formwork and fixed to the central axis of the cavity of the peripheral formwork. The gap between the H-shaped steel and the peripheral formwork is the pouring space for cast-in-place concrete; Among them, the peripheral formwork includes a stainless steel pipe, ultra-high performance concrete, a steel reinforcement cage, a perforated steel plate in a shape of a Chinese character "hui" and a PBL plate. The stainless steel pipe is arranged on the outermost side. The PBL plates are arranged at intervals on the inner surface of the stainless steel pipe. The steel reinforcement cage is fixed to the inner surface of the stainless steel pipe and is formed into a hollow peripheral formwork by casting with ultra-high performance concrete; The perforated steel plate in a shape of a Chinese character "hui" is arranged at both ends of the peripheral formwork.

2. The precast, modular steel-concrete composite column without formwork removal as described in claim 1, characterized in that, The peripheral formwork is set as a rectangular cross-section hollow column structure, and its outer wall and inner wall are both flat surfaces.

3. The precast, modular steel-concrete composite column without formwork removal as described in claim 1, characterized in that, The steel reinforcement cage includes several main reinforcements extending along the axial direction of the stainless steel pipe and closed stirrups arranged around the main reinforcements.

4. The precast, assembled steel-concrete rectangular composite column without formwork removal as described in claim 3, characterized in that, The closed stirrup includes one of an annular stirrup or a continuous spiral stirrup.

5. A precast, modular steel-concrete composite column without formwork removal as described in claim 1, characterized in that, The length of the H-shaped steel is greater than the length of the peripheral formwork.

6. A precast, modular steel-concrete composite column without formwork removal as described in claim 3, characterized in that, The outer edge of the perforated steel plate in a shape of a Chinese character "hui" is flush with the stainless steel pipe, and the inner edge is flush with the inner edge of the high-performance concrete. The perforated steel plate in a shape of a Chinese character "hui" is fixedly connected to the main reinforcement.

7. A precast, modular steel-concrete composite column without formwork removal as described in claim 1, characterized in that, The perforated steel plate in a shape of a Chinese character "hui" is provided with reserved holes.

8. A precast, modular steel-concrete composite column without formwork removal as described in claim 7, characterized in that, There are 3 reserved holes at each of the four edges of the perforated steel plate in a shape of a Chinese character "hui".

9. A precast, modular steel-concrete composite column without formwork removal as described in claim 5, characterized in that, Reserved bolt holes are provided at both ends of the H-shaped steel.

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