Reinforcing device and method for steel tube recycled concrete and steel beam joint

Abstract

The invention relates to a reinforcing device and method for a steel pipe recycled concrete and steel beam joint, and aims to improve the bearing capacity, durability and anti-seismic property of the joint. Along with complexity of a building structure, a traditional steel beam and concrete structure joint has the problems of insufficient bearing capacity, poor durability, poor anti-seismic property and the like, and especially in a steel pipe recycled concrete structure, the joint is prone to fatigue damage and structural failure. The method comprises the steps that the surfaces of a steel pipe and a steel beam are pretreated, a proper CFRP material is selected and cut, the surfaces are coated with CFRP dipping glue, and the anti-seismic property is enhanced through stud anchoring. And finally, curing and protective layer treatment are completed. Test results show that the bearing capacity and shock resistance of the structural joints are remarkably improved through the method, the performance of damaged joints can be effectively recovered and even improved, reliable guarantee is provided for safety of the steel pipe recycled concrete structure, and the method has wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of building engineering and structural reinforcement, and in particular to a reinforcement device and method for a steel tube recycled concrete and steel beam node. Background Art

[0002] At present, with the increasing complexity of building structures and the increasing requirements for high-performance structures, traditional steel beam and concrete structure nodes are facing a series of challenges. These nodes usually bear important loads of the structure, and with the increase of service life, the bearing capacity of these nodes gradually decreases, the durability decreases, and the seismic performance is insufficient. In particular, in the application of recycled concrete, the strength and stability of concrete are often affected by the source of raw materials and production processes. These factors determine the differences in their physical properties, resulting in weak bonding between steel beams and concrete, and increasing the risk of fatigue damage and damage to structural nodes under stress. In building structures, the connection between steel beams and concrete nodes is not only the key to bearing capacity, but also a decisive factor in the overall stability of the structure.

[0003] Steel tube recycled concrete structure has gradually become a new structural form in modern architecture due to its light weight, good compressive performance and high economy. The use of recycled concrete helps to achieve sustainable utilization of building materials, but its strength, toughness and stability are still far behind traditional concrete. In particular, the performance problem of steel tube recycled concrete steel beam nodes has become an important bottleneck affecting the safety of the entire structure. Although the steel tube itself has high strength and can effectively resist external compressive loads, the tensile strength and bending resistance of recycled concrete are relatively poor, which makes the connection node between the steel beam and the concrete prone to structural failure under stress conditions, especially under long-term loads or vibrations, the node may experience crack expansion, interface detachment or damage.

[0004] In order to improve the performance of steel tube recycled concrete steel beam nodes, traditional reinforcement methods often rely on technologies such as steel plate wrapping, concrete reinforcement or external support. However, although these methods can improve structural performance in the short term, they have obvious shortcomings in terms of construction complexity, reinforcement effect, cost, and long-term durability. Although steel plate wrapping can provide additional bearing capacity, its increased deadweight and construction difficulty cannot be ignored. Although concrete reinforcement can improve the overall strength of structural nodes, its construction process is complicated and may lead to an increase in the volume of the original structure, affecting space utilization. In addition, traditional methods are often difficult to effectively improve the seismic performance of nodes, especially in seismically active areas, where the seismic performance of structural nodes is crucial.

[0005] In this context, carbon fiber reinforced composites (CFRP) have gradually become an important material in the field of structural reinforcement. CFRP materials are gradually being used in the reinforcement and reconstruction of building structures due to their superior properties such as light weight, high strength, corrosion resistance, and fatigue resistance. The specific strength and specific stiffness of CFRP are much higher than those of traditional steel, which enables it to provide a greater reinforcement effect during the reinforcement process without increasing the additional deadweight of the structure, thus avoiding the problem of weight increase in traditional reinforcement methods. CFRP also has excellent corrosion resistance, which makes it have a longer service life in humid and corrosive environments and reduces the frequency of maintenance and replacement. In addition, the fatigue resistance of CFRP materials is significant, which can effectively improve the stability of the structure under long-term loads and vibrations, thereby significantly improving the durability and service life of the entire structure. Although CFRP has achieved certain success in the reinforcement of steel and concrete structures, the research and application of existing technologies for the reinforcement of steel tube recycled concrete-steel beam nodes are still insufficient. Traditional CFRP reinforcement technology usually focuses on the reinforcement effect of a single material, and lacks in-depth research on the complexity of composite structures, especially the mechanical relationship between steel tubes and recycled concrete. As a composite structure, the mechanical behavior of steel tube recycled concrete steel beam node is not only affected by the mechanical properties of steel and concrete itself, but also involves the interaction and matching performance between the two. How to effectively combine CFRP material with steel tube recycled concrete steel beam node to maximize the potential of CFRP material is still a technical problem that needs to be solved urgently.

[0006] In addition, CFRP reinforcement technology faces some challenges during its application. First, the bonding strength and construction process of CFRP directly affect its reinforcement effect. If the bonding is not strong, the reinforcement effect may be greatly reduced, and even safety hazards such as falling off may occur. Secondly, CFRP materials may be affected by environmental factors such as temperature changes, humidity changes, and ultraviolet rays during long-term use, resulting in performance degradation. Therefore, how to improve the construction process of CFRP materials, optimize their bonding properties, and improve their long-term stability in different environments are key directions for future research.

[0007] In general, how to effectively use CFRP materials to reinforce steel tube recycled concrete-steel beam nodes and improve their bearing capacity, durability and seismic performance is an important research topic in the current field of structural reinforcement. Solving this problem can not only provide more reliable technical support for the application of steel tube recycled concrete structures, but also promote the wider application of CFRP materials in construction projects, and promote the sustainable development and safety improvement of building structures. Therefore, further research and innovation on CFRP reinforcement technology will play an important role in the future field of building structure reinforcement. Summary of the invention

[0008] The technical problem solved by the present invention is that the construction is complicated, and there are obvious deficiencies in reinforcement effect, cost, and long-term durability. For this purpose, a reinforcement device and method for a steel tube recycled concrete and steel beam node are provided.

[0009] In order to solve the above technical problems, the present invention provides a reinforcement device for a steel tube recycled concrete and steel beam node, comprising a steel tube recycled concrete column, which is used as the foundation of a bearing structure;

[0010] Node core connectors, which are fixedly connected to the steel tube recycled concrete columns and steel beams;

[0011] A CFRP material layer covering the outer surface of the steel tube recycled concrete column, the node core connector and the partial steel beam;

[0012] Studs, which are used to fix the CFRP material layer to the steel beam;

[0013] The beam end is anchored to the steel beam by means of bolts.

[0014] A reinforcement method for a steel tube recycled concrete and steel beam node, comprising the following steps: Step 1, node surface pretreatment: cleaning the steel tube and steel beam surface to remove dust, oil and other impurities to ensure the bonding strength of the CFRP material;

[0015] Step 2: Pre-drill holes at the beam ends for later bolt anchoring;

[0016] Step 3: CFRP material selection and preparation: Select CFRP strips or cloth suitable for reinforcement and cut them according to the shape and stress conditions of the nodes;

[0017] Step 4: CFRP material bonding: Apply the CFRP material evenly to the surface of the steel pipe and steel beam through the CFRP impregnation adhesive to ensure uniform and dense bonding;

[0018] Step 5: Anchor the pre-drilled holes at the ends of the beams to enhance the seismic performance of the CFRP nodes;

[0019] Step 6: Curing and protection of the reinforcement layer: After bonding is completed, let it stand for 1-3 days until the CFRP material is cured to ensure a close bond between the material and the structure, and then apply the protective layer.

[0020] Preferably, in step three, the CFRP material is CJ200-II carbon fiber cloth, which has a calculated thickness of 0.111 mm, a tensile strength of 3325.4, an elastic modulus of 240000, and an elongation of 1.74%, and is cut into a suitable size according to the node shape.

[0021] Preferably, in step 4, CFRP impregnation glue is used and evenly coated on the cleaned steel pipe and concrete surface, and the coating thickness is controlled to be 0.4-0.6 mm.

[0022] Preferably, in step five, the pre-drilled holes at the ends of the beams are anchored with bolts at a distance of 30-50 mm from the ends of the beams to enhance the integrity of the structure.

[0023] Preferably, in step six, curing is carried out at room temperature for 24-72 hours to ensure that the impregnating glue is completely cured. After curing, a protective coating treatment is performed to prevent the influence of environmental moisture on the CFRP material.

[0024] Compared with the related art, the present invention has the following beneficial effects:

[0025] The present invention conducts quasi-static tests and numerical simulations on steel tube recycled concrete-steel beam nodes with different degrees of damage, and adopts the reinforcement method of the present invention. First, the surface of the node is cleaned and surface impurities are removed, and then CJ200-II carbon fiber cloth is selected for reinforcement. The CFRP cloth is bonded to the steel tube and the concrete surface by CFRP impregnation glue, and is bolted and anchored at the end of the beam. The reinforcement effect after curing is significant. The reinforcement method increases the bearing capacity of undamaged specimens by 22.9%, restores the bearing capacity of severely damaged specimens to even slightly higher than that of unreinforced specimens, increases the node energy consumption capacity by 56.0% and 27.4% respectively, and significantly enhances the seismic performance.

[0026] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a schematic diagram of the structure of the CFRP reinforced steel tube recycled concrete column-steel beam node of the present invention;

[0029] Figure 2 A partial view of the CFRP reinforcement of the steel tube recycled concrete column-steel beam node of the present invention;

[0030] Figure 3 This is a stress analysis diagram of the steel tube recycled concrete column-steel beam node when it is destroyed.

[0031] Numbers in the figure:

[0032] 1. Steel tube recycled concrete column; 2. Node core connector; 3. CFRP material layer; 4. Steel beam; 5. Studs; 6. Beam end. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1-3 A reinforcement device for a steel tube recycled concrete and steel beam node, comprising a steel tube recycled concrete column 1, used as the basis of a bearing structure; a node core connector 2, which is fixedly connected to the steel tube recycled concrete column 1 and the steel beam 4; a CFRP material layer 3, which covers the steel tube recycled concrete column 1, the node core connector 2 and a partial outer surface of the steel beam 4; a bolt 5, which is used to fix the CFRP material layer 3 to the steel beam 4; and a beam end 6, which is anchored to the steel beam 4 through the bolt 5.

[0035] A reinforcement method for steel tube recycled concrete and steel beam four nodes, comprising the following steps:

[0036] Step 1: Node surface pretreatment: clean the surface of steel pipe and steel beam 4 to remove dust, oil and other impurities to ensure the bonding strength of CFRP material; Step 2: pre-drill the beam end 6 for later bolt 5 anchoring; Step 3: CFRP material selection and preparation: select CFRP sheet or cloth suitable for reinforcement, and cut it according to the shape and stress conditions of the node; Step 4: CFRP material bonding: apply CFRP material evenly to the surface of steel pipe and steel beam 4 through CFRP impregnation adhesive to ensure uniform and dense bonding; Step 5: anchor bolt 5 at the pre-drilled hole at the beam end 6 to enhance the seismic performance of CFRP on the node; Step 6: Curing and protection of reinforcement layer: after bonding is completed, let it stand for 1-3 days until the CFRP material is cured to ensure the close bonding between the material and the structure, and then perform protective layer treatment.

[0037] Furthermore, in the step three, the CFRP material is CJ200-II carbon fiber cloth, which has a calculated thickness of 0.111 mm, a tensile strength of 3325.4, an elastic modulus of 240000, and an elongation of 1.74%. It is cut into a suitable size according to the node shape. In the step four, CFRP impregnation glue is used to evenly apply it to the cleaned steel pipe and concrete surface, and the coating thickness is controlled at 0.4-0.6 mm. In the step five, the pre-punched holes at the beam end 6 are anchored with bolts 5 at a distance of 630-50 mm from the beam end to enhance the integrity of the structure. In the step six, it is cured at room temperature for 24-72 hours to ensure that the impregnation glue is completely cured. After the curing is completed, a protective coating treatment is performed to prevent the influence of environmental moisture on the CFRP material.

[0038] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A reinforcement device for steel tube recycled concrete and steel beam nodes, characterized in that: It comprises a steel tube recycled concrete column (1) used as the foundation of the bearing structure; A node core connector (2) which is fixedly connected to the steel tube recycled concrete column (1) and the steel beam (4); A CFRP material layer (3) covering the outer surface of the steel tube recycled concrete column (1), the node core connector (2) and a part of the steel beam (4); A bolt (5) for fixing the CFRP material layer (3) to the steel beam (4); The beam end (6) is anchored to the steel beam (4) via bolts (5).

2. The reinforcement method of a steel tube recycled concrete and steel beam node according to claim 1, characterized in that: The steps include: Step 1: Node surface pretreatment: Clean the surface of the steel pipe and steel beam (4) to remove dust, oil and other impurities to ensure the bonding strength of the CFRP material; Step 2: Pre-drilling the beam end (6) for later anchoring of the bolts (5); Step 3: CFRP material selection and preparation: Select CFRP strips or cloth suitable for reinforcement and cut them according to the shape and stress conditions of the nodes; Step 4: CFRP material bonding: The CFRP material is evenly applied to the surface of the steel pipe and the steel beam (4) by means of the CFRP impregnation adhesive to ensure uniform and dense bonding; Step 5: Anchor bolts (5) at the pre-drilled holes at the beam ends (6) to enhance the seismic performance of the CFRP nodes; Step 6: Curing and protection of the reinforcement layer: After bonding is completed, let it stand for 1-3 days until the CFRP material is cured to ensure a close bond between the material and the structure, and then apply the protective layer.

3. The reinforcement method of a steel tube recycled concrete and steel beam node according to claim 1, characterized in that: In the step three, the CFRP material is CJ200-II carbon fiber cloth, which has a calculated thickness of 0.111 mm, a tensile strength of 3325.4, an elastic modulus of 240000, and an elongation of 1.74%, and is cut into a suitable size according to the node shape.

4. The reinforcement method of a steel tube recycled concrete and steel beam node according to claim 1, characterized in that: In the step 4, CFRP impregnation adhesive is used and evenly coated on the cleaned steel pipe and concrete surface, and the coating thickness is controlled at 0.4-0.6 mm.

5. The reinforcement device and method of the steel tube recycled concrete and steel beam node according to claim 1, characterized in that: In the step 5, the pre-punched holes at the beam end (6) are anchored with bolts (5) at a distance of 30-50 mm from the beam end (6) to enhance the integrity of the structure.

6. The reinforcement method of a steel tube recycled concrete and steel beam node according to claim 1, characterized in that: In step six, curing is performed at room temperature for 24-72 hours to ensure that the impregnating adhesive is completely cured. After curing, a protective coating treatment is performed to prevent the influence of environmental moisture on the CFRP material.

Images