Low-grade concrete construction method for frame beam-column joints provided with reinforcing steel bars
By adding reinforced steel bars at the frame beam and column nodes and using low-strength concrete, the problem of multiple cold joints and mixed pouring in traditional construction is solved, the resistance and construction efficiency of the nodes are improved, and the subsequent reinforcement cost is reduced.
Patent Information
- Application Number
- CN202510006935.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-03
- Publication Date
- 2025-03-25
AI Technical Summary
There are multiple cold joints, mixed pouring and quality control problems in the construction of traditional frame beam and column nodes, resulting in complex construction, unstable quality, and high subsequent reinforcement costs.
By adding reinforced steel bars in the core stress area of the frame beam and column nodes, and using low-strength concrete to replace the overall casting, up to six strength levels can be replaced, one-time casting is achieved and cold joints are reduced in construction.
The bending and shear resistance of nodes is improved, the construction process is simplified, the mixed pouring phenomenon is avoided, safety hazards and subsequent reinforcement costs are reduced, and construction quality and efficiency are improved.
Smart Images
Figure CN119686439A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of civil structure engineering, and in particular to a method for constructing a frame beam-column node equipped with reinforced steel bars using low-grade concrete. Background Art
[0002] With the gradual advancement of my country's urbanization process, the proportion of high-rise buildings in newly built buildings is increasing. The vertical components such as columns of these high-rise buildings are compressive components, which have high requirements for concrete strength, and generally use higher-strength concrete; while the horizontal components are mainly flexural, and the strength requirements for concrete are lower, and generally use low-strength concrete. The frame beam-column node is the intersection of vertical and horizontal components. It is a key part and has a decisive influence on the overall seismic performance of the structure. In structural design, there is a concept requirement of "strong columns, weak beams, and stronger nodes". Therefore, the concrete strength of the frame node must be implemented in accordance with the high-strength concrete of the vertical components, and the construction quality must be ensured.
[0003] The traditional approach is to add fences and air bags outside the node area to separate them, organize and dispatch the concrete strength in a refined manner, ensure that the high- and low-strength concrete is properly matched when it enters the site, and cast the vertical components, beam-column nodes, and horizontal components in three times. Strictly control the high-strength concrete in the node area to achieve initial setting before casting the low-strength concrete outside the node to ensure that no mixing occurs. The above strict requirements on process, organization, and control require relatively refined and strict human management and a longer construction period to be achieved.
[0004] There are the following technical and practical problems:
[0005] 1. The construction process consists of three pouring steps, and there are multiple cold joints in the construction, which may cause defects;
[0006] Second, node construction requires high on-site supervision and worker proficiency, and it is difficult to ensure that all aspects are accurate and in place to avoid mixing and excessive cold joints;
[0007] 3. In actual projects, it is difficult to accurately mix concrete of different strengths and match them to the site. The appearance of cold joints during mixing or long periods of time is basically inevitable.
[0008] Fourth, only individual nodes are randomly inspected and evaluated during the project, and a large number of nodes are still uninspected. These nodes have reduced strength due to the existence of mixed pouring or cold joints, and the possibility of safety impact is relatively high. For nodes that are found to be insufficiently strong, the subsequent reinforcement costs and time costs of the project are huge and unacceptable. Summary of the invention
[0009] The object of the present invention is to provide a method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete to solve the problems raised in the above-mentioned background technology.
[0010] To achieve the above object, the present invention provides the following technical solution: a method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete, comprising the following steps:
[0011] S1: Complete the binding of the original designed reinforcement and reinforced reinforcement, determine the number, position and fixing method of the built-in reinforcement, and arrange them in the core stress-bearing area of the node;
[0012] S2: Install all the reinforcement bars in the frame beam-column joints as required;
[0013] S3: pouring high-strength grade concrete in the lower column concrete area;
[0014] S4: Pour low-strength concrete into the core area of the node and the beam and slab concrete area at one time.
[0015] Preferably, the reinforcing steel bars in step S1 include: reinforcing dowel bars, lower horizontal reinforcing steel mesh, upper horizontal reinforcing steel mesh, frame beam longitudinal bars, frame column longitudinal bars, lower column stirrups, reinforcing core area stirrups and upper column stirrups.
[0016] Preferably, when the lower horizontal reinforcing steel mesh and the upper horizontal reinforcing steel mesh overlap with the longitudinal reinforcement of the frame beam and the spacing is too close, the longitudinal reinforcement of the frame beam can be used to replace the lower horizontal reinforcing steel mesh and the upper horizontal reinforcing steel mesh.
[0017] Preferably, the reinforcing dowel bars and the longitudinal bars of the frame columns are spot welded and tied together to prevent displacement and loosening during concrete pouring.
[0018] Preferably, the reinforcement ratio of the reinforcing dowel bars is not less than 1%, and the reinforcing dowel bars extend into the upper column concrete and the lower column concrete, with an extension length of not less than 30 centimeters.
[0019] Preferably, when the beam is arranged eccentrically, the lower horizontal reinforcing steel mesh and the upper horizontal reinforcing steel mesh can be arranged on one side of the longitudinal reinforcement of the frame beam, so that the steel mesh is evenly arranged in the concrete of the core area of the node.
[0020] Preferably, the volume ratio of the core area of the reinforced core area stirrup node is increased in diameter and the spacing is increased.
[0021] Preferably, the horizontal steel mesh in the beam-column node meets the reinforcement ratio requirements, is evenly arranged on the outside of the longitudinal reinforcement of the beam, and the vertical spacing of the steel mesh is not less than half of the minimum cross-sectional width of the frame column.
[0022] Preferably, in step S3, the maximum difference between the concrete strength grade of the lower column concrete area and the strength grade of the node core area concrete and the beam and slab concrete area is six grades.
[0023] Technical effects and advantages of the present invention:
[0024] During concrete construction, the present invention adds reinforcing steel bars at the key stress-bearing positions of the frame beam-column nodes to enhance the bending and shear resistance of the nodes, and low-strength concrete can be used in the node area instead of integral casting, which can replace up to six strength levels, making construction convenient, avoiding multiple construction cold joints, and improving construction quality. At the same time, it can reduce one casting process, so that the frame beam-column nodes and the beams and slabs can be cast with low-strength concrete simultaneously, and the occurrence of mixed concrete casting can be avoided from the construction method, thereby avoiding safety hazards caused by quality problems and unacceptable high costs such as reinforcement and transformation. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 A flow chart of the construction method of low-grade concrete for the frame beam-column node configured with reinforced steel bars according to the present invention.
[0026] Figure 2 A three-dimensional schematic diagram of a frame beam-column node configured with reinforcing steel bars according to the present invention.
[0027] Figure 3 It is a schematic cross-sectional view of the node area of the present invention.
[0028] Figure 4 It is a schematic diagram of a cross-section of a column of the present invention.
[0029] In the figure: 1. reinforcing dowel bars; 21. lower horizontal reinforcing steel mesh; 22. upper horizontal reinforcing steel mesh; 3. lower column concrete; 41. beam and slab concrete; 42. frame beam longitudinal bars; 5. node core area concrete; 6. frame column longitudinal bars; 71. lower column stirrups; 72. reinforcing core area stirrups; 73. upper column stirrups; 8. upper column concrete. DETAILED DESCRIPTION
[0030] 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.
[0031] The present invention provides Figure 1-4 A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete includes the following steps:
[0032] S1: Complete the binding of the original designed reinforcement and reinforced reinforcement, determine the number, position and fixing method of the built-in reinforcement, and arrange them in the core stress-bearing area of the node;
[0033] S2: Install all the reinforcement bars in the frame beam-column joints as required;
[0034] S3: pouring high-strength grade concrete in area 3 of the lower column concrete;
[0035] S4: low-strength grade concrete is poured in one go on the node core area concrete 5 and the beam and slab concrete 41 area.
[0036] During concrete construction, reinforcing steel bars are added to the key stress-bearing parts of the frame beam-column nodes to enhance the nodes' bending and shear resistance. Low-strength concrete can be used in the node area instead of integral pouring, and up to six strength levels can be replaced, which facilitates construction, avoids multiple construction cold joints, and improves construction quality. At the same time, it can reduce one pouring process, so that the frame beam-column nodes and beams and slabs can be poured with low-strength concrete simultaneously. The occurrence of mixed concrete pouring can be avoided from the construction method, and the safety hazards caused by quality problems and unacceptable high costs such as reinforcement and transformation can be avoided. At the same time, the interception measures used in the traditional secondary pouring of concrete of different grades are cancelled, which improves construction efficiency and avoids construction problems such as multiple cold joints and mixed pouring caused by multiple constructions.
[0037] Specifically, the reinforced steel bars in step S1 include: reinforced dowel bars 1, lower horizontal reinforced steel mesh 21, upper horizontal reinforced steel mesh 22, frame beam longitudinal bars 42, frame column longitudinal bars 6, lower column stirrups 71, reinforced core area stirrups 72 and upper column stirrups 73. The reinforced dowel bars 1 can provide vertical reinforced support. The lower horizontal reinforced steel mesh 21 and the upper horizontal reinforced steel mesh 22 can enhance the shear and bending resistance of the node in the horizontal direction. The frame beam longitudinal bars 42 and the frame column longitudinal bars 6 constitute the main force-bearing steel bars of the frame. The lower column stirrups 71, the reinforced core area stirrups 72 and the upper column stirrups 73 constrain the core area of the column, and jointly improve the overall bearing capacity and seismic performance of the node, ensuring the stability of the structure under complex stress conditions. The combination of different types of steel bars can be targeted at the stress characteristics of the node in different directions and working conditions for targeted reinforcement, avoiding the stress weak points that may be caused by a single type of steel bar, so that the node can more effectively transmit and disperse the internal force, and extend the service life of the structure.
[0038] Furthermore, when the lower horizontal reinforcing steel mesh 21 and the upper horizontal reinforcing steel mesh 22 overlap with the frame beam longitudinal reinforcement 42 and the spacing is too close, the frame beam longitudinal reinforcement 42 can be used to replace the lower horizontal reinforcing steel mesh 21 and the upper horizontal reinforcing steel mesh 22. When the lower horizontal reinforcing steel mesh 21 and the upper horizontal reinforcing steel mesh 22 overlap with the frame beam longitudinal reinforcement 42 and the spacing is too close, the frame beam longitudinal reinforcement 42 can be used to replace them. This can avoid the steel bars being too dense and occupying too much space, making the spatial layout of the node area more reasonable, which is conducive to the pouring and compactness of the concrete, and avoids quality problems such as honeycombs and rough surfaces caused by the inability to fully fill the concrete due to overcrowding of the steel bars, thereby improving the integrity and durability of the structure, and at the same time simplifying the arrangement of the steel bars, reducing the difficulty and workload of operations during construction, and there is no need to arrange multiple layers of steel bars in the overlapping area at the same time. Only the frame beam longitudinal reinforcement 42 is needed to meet the force requirements, saving construction time and improving construction efficiency. At the same time, it also reduces the risk of construction quality problems such as steel bar position deviation caused by the staggered multiple layers of steel bars, makes it easier for construction personnel to operate and control, and can save the use of steel bar materials to a certain extent. If no replacement is made, the number and specifications of additional steel bars may need to be increased to meet the design requirements, increasing costs. Through reasonable replacement, the use of steel bars can be reduced and the project cost can be reduced while meeting the structural performance.
[0039] Furthermore, the reinforcing dowel bar 1 and the frame column longitudinal reinforcement 6 are formed into parallel reinforcement by spot welding and binding, which is used to prevent displacement and loosening during the concrete pouring process. The combination of spot welding and binding can provide a strong connection force, and the reinforcing dowel bar 1 and the frame column longitudinal reinforcement 6 are firmly connected together to form an integral parallel reinforcement structure. During the concrete pouring process, the concrete will exert a certain lateral pressure and vibration force on the steel bar. Through this firm connection, the relative displacement between the reinforcing dowel bar 1 and the frame column longitudinal reinforcement 6 can be effectively prevented, and the position of the steel bar in the structure can be ensured to be stable, thereby ensuring the structural stability of the entire frame beam-column node, avoiding displacement and loosening, and making the steel bar stable in the long-term use process. A good stress state is always maintained, and the stress distribution at the node will not change due to the movement of the steel bar, reducing quality problems such as cracks caused by changes in the position of the steel bar, and extending the service life of the structure. At the same time, the construction process of spot welding and binding is relatively mature and simple, easy for construction personnel to operate and master. This method can quickly and effectively connect the reinforcing dowel bar 1 and the longitudinal reinforcement 6 of the frame column at the construction site, improve construction efficiency, and ensure construction progress. The firmness of the connection is helpful in the subsequent construction process, such as concrete pouring, etc., to better protect and fix the steel structure, reduce the damage to the steel connection caused by construction operations, and ensure the integrity of the steel structure.
[0040] Furthermore, the reinforcement ratio of the reinforcing bar 1 is not less than 1%, and it extends to the upper column concrete 8 and the lower column concrete 3, with an extension length of not less than 30 cm. A higher reinforcement ratio can enhance the bearing capacity and deformation resistance of the reinforcing bar. The reinforcement ratio of not less than 1% ensures that the reinforcing bar 1 plays an effective reinforcing role between the upper and lower column concrete 3, and can better withstand the load transfer from the upper structure and the internal forces generated by concrete shrinkage, temperature changes, etc., improve the overall strength and stability of the structure, and extend to the upper column concrete 8 and the lower column concrete 3 with a length of not less than 30 cm, increasing the combination range of the reinforcing bar 1 and the upper and lower column concrete 3, making the internal force transmission between the upper and lower columns more stable and reliable, avoiding the structural weak points caused by stress concentration at the junction of the upper and lower column concrete 3, and further improving the overall performance of the structure.
[0041] Furthermore, when the beam is eccentrically arranged, the lower horizontal reinforcing steel mesh 21 and the upper horizontal reinforcing steel mesh 22 can be arranged on one side of the longitudinal reinforcement 42 of the frame beam, so that the steel mesh is evenly arranged in the concrete 5 of the node core area. This can avoid the situation where the steel bars in some parts of the node core area are densely packed while the steel bars in other parts are sparse due to the eccentric arrangement of the beam, so that the stress on the node core area in all directions is more uniform. The evenly distributed steel mesh can better resist the internal forces from all directions, improve the shear and bending resistance of the node core area, reduce stress concentration, and thus ensure the overall stress performance of the structure. The evenly arranged steel mesh is conducive to the pouring and compaction of concrete. During the concrete pouring process, the concrete can flow more smoothly, avoiding the situation where concrete is accumulated or difficult to fill in some parts due to uneven distribution of steel bars, ensuring that the concrete can fully fill the node core area, improve the density and integrity of the concrete, reduce the occurrence of cracks, and enhance the durability of the structure.
[0042] Furthermore, the volume stirrup ratio of the core area of the node is increased, the diameter is increased, and the spacing is increased. The core area of the node is effectively lateral restrained by the close arrangement of the stirrups 72. The volume stirrup ratio of the stirrups 72 is increased, and the spacing is increased, which can significantly improve the shear resistance of the core area of the node. The stirrups surround the concrete in the core area of the node like a "cage". When the node is subjected to shear force, the stirrups can effectively limit the lateral deformation of the concrete and prevent the development and extension of the oblique cracks in the concrete, thereby improving the shear strength of the core area of the node and ensuring the safety of the structure under horizontal loads or earthquakes. The closely arranged stirrups can better coordinate the concrete and steel bars in the core area of the node, so that the concrete can fully exert its compressive strength when under pressure, and the steel bars can fully exert their tensile strength when under tension, and jointly bear the external force, thereby improving the overall bearing capacity of the core area of the node. The effective lateral restraint formed on the concrete 5 in the core area of the node can reduce the deformation of the core area of the node during the force process. Closely arranged stirrups can limit the lateral expansion of concrete, reduce the shear deformation and bending deformation in the core area of the node, enable the structure to maintain a good geometric shape and stability after being subjected to force, reduce structural damage and destruction caused by excessive deformation, and improve the seismic resistance and performance of the structure.
[0043] Furthermore, the horizontal steel mesh in the beam-column joint meets the reinforcement ratio requirements, is evenly arranged outside the beam longitudinal reinforcement, and the vertical spacing of the steel mesh is not less than half of the minimum cross-sectional width of the frame column. The horizontal steel mesh is evenly arranged outside the beam longitudinal reinforcement, and can form a force-bearing system that works in coordination with the beam longitudinal reinforcement. At the beam-column joint, the horizontal steel mesh can share part of the bending moment and shear force borne by the beam longitudinal reinforcement, increase the shear and bending resistance of the node area, and effectively avoid premature damage at the node due to concentrated force. The horizontal steel mesh that meets the reinforcement ratio requirements can improve the restraint effect of the concrete in the node area, reduce the cracking and deformation of the concrete during the force process, and enhance the overall stability and durability of the node. It is stipulated that the vertical spacing of the steel mesh is not less than half of the minimum cross-sectional width of the frame column, which is convenient for construction operations and the arrangement of steel bars, and avoids the steel bars being too dense to affect the pouring and vibration of the concrete. At the same time, it is also beneficial to ensure the thickness of the protective layer of the steel bars and improve the durability of the steel bars.
[0044] Furthermore, in step S3, the maximum difference between the concrete strength grade of the lower column concrete 3 area and the strength grade of the node core area concrete 5 and the beam and slab concrete 41 area is six grades, and the greater the degree of reinforcement of the node by the reinforcing steel bars, the greater the difference between the concrete strength grade of the lower column concrete 3 area and the strength grade of the node core area concrete 5 and the beam and slab concrete 41 area. When the degree of reinforcement of the node by the reinforcing steel bars is large, by increasing the difference between the strength grade of the lower column concrete 3 area and the strength grade of the node core area and the beam and slab concrete 41 area, the performance difference between concretes of different strength grades can be utilized to form a more obvious strength gradient and deformation coordination mechanism at the node. The high-strength lower column concrete 3 can provide stronger support and bearing capacity for the node, while the node core area and beam-slab concrete 41 can play a role in buffering and coordinating deformation to a certain extent, which helps to better play the characteristics of each part of the material, enhance the collaborative working ability of the entire structure during the force process, improve the overall earthquake resistance, shear resistance and other properties of the structure, enable the structure to more reasonably distribute internal forces under complex force conditions, and reduce the risk of local stress concentration and damage. Such a design arrangement can flexibly adjust the concrete strength grade of different areas according to actual engineering needs and structural characteristics, so as to better carry out work such as steel bar arrangement during construction. At the same time, it also provides a certain basis and reference for quality control, which helps to ensure the construction quality and safety of the structure.
[0045] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete, characterized in that: The following steps are involved: S1: Complete the binding of the original designed reinforcement and reinforced reinforcement, determine the number, position and fixing method of the built-in reinforcement, and arrange them in the core stress-bearing area of the node; S2: Install all the reinforcement bars in the frame beam-column joints as required; S3: pouring high-strength grade concrete in the lower column concrete (3) area; S4: low-strength grade concrete is poured in one go on the node core area concrete (5) and the beam and slab concrete (41) areas.
2. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 1, characterized in that: The reinforcing steel bars in step S1 include: reinforcing dowel bars (1), a lower horizontal reinforcing steel mesh (21), an upper horizontal reinforcing steel mesh (22), frame beam longitudinal bars (42), frame column longitudinal bars (6), lower column stirrups (71), reinforcing core area stirrups (72) and upper column stirrups (73).
3. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 2, characterized in that: When the lower horizontal reinforcing steel mesh (21) and the upper horizontal reinforcing steel mesh (22) overlap with the frame beam longitudinal bars (42) and the spacing is too close, the frame beam longitudinal bars (42) can be used to replace the lower horizontal reinforcing steel mesh (21) and the upper horizontal reinforcing steel mesh (22).
4. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 2, characterized in that: The reinforcing dowel bars (1) and the frame column longitudinal bars (6) are spot welded and tied together to form joint bars, so as to prevent displacement and loosening during the concrete pouring process.
5. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 4, characterized in that: The reinforcement ratio of the reinforcing dowel bars (1) is not less than 1%, and the reinforcing dowel bars (1) extend into the upper column concrete (8) and the lower column concrete (3), with an extension length of not less than 30 centimeters.
6. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 2, characterized in that: When the beam is arranged eccentrically, the lower horizontal reinforcing steel mesh (21) and the upper horizontal reinforcing steel mesh (22) can be arranged on one side of the longitudinal reinforcement (42) of the frame beam, so that the steel mesh is evenly arranged in the concrete (5) of the core area of the node.
7. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 2, characterized in that: The reinforced core area stirrups (72) have a larger diameter and a denser spacing in the core area of the node volume.
8. A method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 7, characterized in that: The horizontal steel mesh in the beam-column node meets the reinforcement ratio requirements, is evenly arranged on the outside of the longitudinal reinforcement of the beam, and the vertical spacing of the steel mesh is not less than half of the minimum cross-sectional width of the frame column.
9. The method for constructing a frame beam-column node with reinforced steel bars using low-grade concrete according to claim 1, characterized in that: In the step S3, the maximum difference between the concrete strength grade of the lower column concrete (3) area and the strength grade of the node core area concrete (5) and the beam and slab concrete (41) area is six grades.