A force transmission support for reinforced concrete frame beam-column joint section enlargement reinforcement

Abstract

The present application relates to a kind of force support for the reinforced concrete frame beam-column node section increasing reinforcement, closed cylindrical force steel support is provided at the connecting place of frame beam and frame column, closed cylindrical force steel support penetrates concrete floor;Closed cylindrical force steel support is composed of upper layer "mouth" shape steel support, lower layer "mouth" shape steel support and vertical steel connecting piece;Upper layer "mouth" shape steel support is located above concrete floor and is arranged along the top of concrete floor, lower layer "mouth" shape steel support is located below concrete floor and is arranged along the lower flange of frame beam;Vertical steel connecting piece is arranged along beam height direction, its upper end is close to the surface of upper layer "mouth" shape steel support steel plate, lower end is close to the surface of lower layer "mouth" shape steel support steel plate.The node of the present application section increasing reinforcement is simple in construction, high in safety, green and environmental protection, and the spliced ribbed steel plate component can be processed in factory, which is a new type of reinforced concrete frame beam-column node reinforcement technology worthy of popularization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reinforcement and reconstruction of existing engineering structures, in particular to a cylindrical force transmission support for reinforcing the section of a reinforced concrete frame beam-column joint and a reinforcing method thereof. BACKGROUND

[0002] Reinforced concrete frame structures are widely used in modern buildings, and the frame beam-column joint is a key part of the structure, mainly composed of a joint core area where the beam and column intersect and the beam and column ends connected to the core area, which plays a role in transmitting, distributing internal forces and ensuring the integrity of the frame structure. Due to the intersection of the beam and column reinforcements at the beam-column joint of the concrete frame structure, the region has a complex structure, and the joint core area mainly bears the axial force, shear force and bending moment transmitted by the column and beam. When the beam axis is eccentric to the column, a torque is also generated. In addition, temperature changes and foundation settlement can cause corresponding internal forces at the joint, so the stress condition of the beam-column joint area is very complex. When the frame structure joint is not properly designed or constructed, or the use environment or function changes, or the bearing capacity is insufficient, or the ductility, stiffness or seismic performance does not meet the requirements due to the improvement of structural seismic requirements, the joint needs to be reinforced and strengthened. Meanwhile, a large amount of experimental research data and earthquake disaster investigations show that the joint core area is the most vulnerable part, but there are still a large number of existing frame structure beam-column joint core areas in China that have insufficient shear bearing capacity, which seriously affects the safety performance of the structure.

[0003] The beam-column joint is difficult to reinforce and construct due to its special location. The selection of a reasonable reinforcement method for the joint should consider safety, applicability, economy and rationality after reinforcement. The current methods for reinforcing the beam-column joint include increasing the section, adhering steel, carbon fiber reinforcement and replacing concrete reinforcement, which can significantly improve the shear bearing capacity and ductility of the joint. By analyzing and comparing some existing beam-column joint reinforcement methods, the adhering steel method and the carbon fiber reinforcement method are not suitable for later use in engineering due to the need to consider the durability of structural glue and the difference between the reinforcement material and the original material. The replacement of concrete reinforcement method needs to consider the large number of steel bars at the intersection of the beam and column and the unloading problem, which is difficult to construct. The section reinforcement method is a method that wraps a certain amount of concrete outside the reinforced concrete member to increase the cross-sectional area of the member, and if necessary, appropriately adds steel bars to the wrapped concrete part to achieve the purpose of strengthening the structure. The commonly used methods include single-sided thickening, double-sided thickening, three-sided thickening and four-sided thickening, which can significantly improve the ductility and bearing capacity of the joint area and enhance the stability of the building structure, thereby being applied to concrete structures in building engineering.

[0004] As a widely used reinforcement method, the cross-section enlargement method also presents some design and construction challenges. In some structures, the enlarged cross-section reinforcement method can limit the reinforcement area due to spatial obstacles created by the two-way frame beams and columns. Furthermore, the dense reinforcement during rebar installation can lead to construction difficulties and serious damage to the original structure. Additionally, some components, such as steel-concrete composite columns, cannot meet the rebar installation requirements, preventing the application of enlarged cross-section reinforcement in some urban renewal projects. Therefore, to address these construction challenges, a cylindrical force-transfer bracket and its reinforcement structure for enlarging the cross-section of reinforced concrete frame beams-column joints have been developed to ensure the safety of the reinforced structure and the quality of the construction. Summary of the Invention

[0005] This invention designs a force transmission support for strengthening the cross-section of reinforced concrete frame beam-column joints by increasing the cross-section. It solves the problems of construction difficulties caused by the dense reinforcement in the core area of ​​the joint when reinforcing beam-column joints of existing engineering structures due to the addition of reinforcement bars, the serious damage to the existing structure caused by the large number of holes for rebar installation, and the inability to properly install reinforcement bars for some projects using structural components.

[0006] To solve the aforementioned technical problems, the present invention adopts the following solution:

[0007] A force-transferring support for reinforcing the cross-section of a reinforced concrete frame beam-column joint, characterized in that: a closed cylindrical force-transferring steel support is provided at the connection between the frame beam and the frame column, the closed cylindrical force-transferring steel support penetrating the concrete floor slab; the closed cylindrical force-transferring steel support consists of an upper "U"-shaped steel support, a lower "U"-shaped steel support, and vertical steel connectors; wherein, the upper "U"-shaped steel support is located above the concrete floor slab and arranged along the top of the concrete floor slab, the lower "U"-shaped steel support is located below the concrete floor slab and arranged along the lower flange of the frame beam; the vertical steel connectors are arranged along the beam height direction, with their upper ends tightly abutting the surface of the upper "U"-shaped steel support plate and their lower ends tightly abutting the surface of the lower "U"-shaped steel support plate.

[0008] Preferably, both the upper and lower "U"-shaped steel supports are composed of multiple spliced ​​ribbed steel plates. The horizontal surface of the spliced ​​ribbed steel plates is closely attached to the top of the concrete floor slab and the lower flange of the frame beam, and the vertical surface is closely attached to the side of the frame column. Adjacent spliced ​​ribbed steel plates are welded around the frame column to form the upper and lower "U"-shaped steel supports.

[0009] Preferably, each spliced ​​ribbed steel plate comprises two spliced ​​steel plates that are vertically welded along the length direction, with triangular stiffening ribs placed inside the vertical spliced ​​steel plates. Multiple triangular stiffening ribs are welded at equal intervals along the length direction of the spliced ​​steel plates to improve the rigidity of the connectors, thus forming a spliced ​​ribbed steel plate.

[0010] Preferably, a triangular opening is made in the core area of ​​the beam-column joint in the concrete floor slab. The size of the opening is slightly larger than the cross-sectional size of the vertical steel connector, so that the vertical steel connector can pass through the concrete floor slab. The vertical steel connector consists of two vertically spliced ​​steel plates arranged vertically close to the frame column, and the arrangement range is from the lower flange of the frame beam to the top of the concrete floor slab.

[0011] Preferably, the two splicing steel plates of each vertical steel connector are welded vertically along the length direction, and triangular stiffening ribs are placed inside the vertical splicing steel plates. Multiple triangular stiffening ribs are welded at equal intervals along the length direction of the splicing steel plates to improve the stiffness of the connector.

[0012] Preferably, the upper L-shaped cross-section of the vertical steel connector is welded to the surface of the upper "U"-shaped steel bracket steel plate that is close to the top of the concrete floor slab, and the lower L-shaped cross-section of the vertical steel connector is welded to the surface of the lower "U"-shaped steel bracket steel plate that is close to the lower flange of the frame beam.

[0013] Preferably, the reinforcing bar sleeves are vertically welded to the spliced ​​steel plate surface around the frame beams and frame columns, the newly added longitudinal bars are screwed to the reinforcing bar sleeves, and the reinforcing bar cage is tied; the closed cylindrical force transmission steel support forms an effective enclosure with the original structural frame beams, frame columns and concrete floor slabs through the newly poured concrete.

[0014] Preferably, the rebar sleeve has an internal thread structure, one end of the rebar sleeve is vertically welded and fixed to the steel plate surface of the closed cylindrical force transmission steel bracket, and the other end is threadedly connected to the newly added longitudinal reinforcement; the newly added longitudinal reinforcement has an external thread structure, and the rebar cage is evenly tied along the length of the newly added longitudinal reinforcement.

[0015] Preferably, after the closed cylindrical force-transmitting steel support and the newly added longitudinal reinforcement are surrounded by self-flowing, dense, and slightly expanding concrete, a new concrete layer is formed for the beam and a new concrete layer for the column.

[0016] A method for fabricating a cylindrical force-transfer bracket for strengthening the cross-section of a reinforced concrete frame beam-column joint by increasing its cross-section includes the following steps:

[0017] Step 1: Measure and lay out the lines around the reinforced frame beams and reinforced frame columns to determine the cross-sectional dimensions of the reinforced frame beams and reinforced frame columns;

[0018] Step 2: Perform base treatment on the contact surfaces of the frame beams and frame columns to ensure a tight bond between the new and old concrete. Remove the concrete protective layer thickness around the frame columns in the concrete floor slab.

[0019] Step 3: The thickness of the triangular stiffening ribs is equal to the thickness of the splicing steel plate. Weld the triangular stiffening ribs to the two vertical limbs of the splicing steel plate at equal intervals to form a splicing ribbed steel plate of the corresponding size.

[0020] Step 4: The horizontally spliced ribbed steel plates corresponding to the cross-sectional dimensions of the frame columns are closely attached to the top of the concrete floor slab where the protective layer thickness has been chiseled around the frame columns. The vertically spliced steel plates are closely attached to the outer side of the frame column walls. The L-shaped cross-section of the spliced ribbed steel plates with the same width as the column is perpendicularly welded to one side of the vertical steel plate extending from the spliced ribbed steel plates wider than the column length adjacent to it, forming an upper "mouth"-shaped steel support closed on four sides.

[0021] Step 5: The spliced ribbed steel plates corresponding to the cross-sectional dimensions of the frame columns are closely attached to the lower flange of the frame beam perpendicular to the column, forming a lower "mouth"-shaped steel support closed on four sides.

[0022] Step 6: Determine the position and range of the opening in the concrete floor slab. The chiseled size of the floor slab at the intersection of the frame beam and the frame column is slightly larger than the triangular opening of the L-shaped cross-section of the vertical spliced steel plate.

[0023] Step 7: The spliced ribbed steel plates with a height from the bottom of the frame beam to the top of the concrete floor slab are arranged along the column direction, passing through the floor slab opening. The upper and lower ends of the L-shaped cross-section are perpendicularly welded to the horizontal steel plates of the upper "mouth"-shaped steel support and the lower "mouth"-shaped steel support, forming the closed cylindrical force-transfer steel support, which tightly wraps the core area of the original structural beam-column joint.

[0024] Step 8: Weld the steel reinforcement sleeves to the corresponding positions of the spliced ribbed steel plates. According to the number and positions of the additional stressed longitudinal steel bars required for the enlarged cross-section reinforcement, vertically weld the steel reinforcement sleeves at the corresponding positions on the steel plates.

[0025] Step 9: Screw the additional longitudinal steel bars into the interior of the steel reinforcement sleeves and connect them with the steel reinforcement sleeves by threading, fixing them on the surface of the closed cylindrical force-transfer steel support.

[0026] Step 10: The steel reinforcement cages are respectively tied at equal intervals along the directions of the frame beam and the frame column where the cross-section needs to be enlarged on the outer sides of the additional longitudinal steel bars.

[0027] Step 11: Bind the formwork around the closed cylindrical force-transfer steel support at the core area of the beam-column joint. Pour self-compacting concrete along the steel plates at the frame beam, the frame column and the concrete floor slab to respectively form an additional concrete layer for the beam and an additional concrete layer for the column.

[0028] Step 12: Maintain the concrete. After removing the formwork, a cylindrical force-transfer support and its reinforcement structure for enlarging the cross-section of the reinforced concrete frame beam - middle column joint are formed.

[0029] The force-transfer support for enlarging the cross-section of the reinforced concrete frame beam - middle column joint has the following beneficial effects:

[0030] (1) The application is a cylindrical force transmission support for reinforcing the reinforced concrete frame beam-middle column joint with increased section, which can effectively improve the normal section bending resistance, shear capacity of the inclined section and the rigidity of the section, reduce the damage to the original frame beam-column joint area during the construction of the embedded steel bar, and solve the construction difficulties caused by the space obstacles in the joint area.

[0031] (2) The spliced ribbed steel plate structure of the reinforced concrete beam-middle column joint area has good support strength, and under the same support strength, the spliced steel plate is lighter in weight, consumes less material, is flexible in construction, occupies less space, saves cost, and therefore has high cost performance. In addition, the triangular stiffening ribs with a thickness not less than that of the spliced steel plate are arranged at equal intervals between the two steel plates of the spliced steel plate, which can improve the critical buckling stress of the steel plate under compression and suppress the buckling deformation of the joint area.

[0032] (3) The spliced ribbed steel plate has less steel consumption, and the steel material is easy to obtain and basically no waste, which has good economic benefits. The adjacent steel plates are connected into a closed force transmission structure through welding, which ensures that the connection rigidity of the beam-column joint area is large and the overall performance is good, and will not produce large deformation under external force, providing a reliable guarantee for the safe use of the original structure.

[0033] (4) The closed cylindrical force transmission steel support has clear force transmission and can replace the traditional embedded steel bar stress path. The new longitudinal reinforcement is connected with the steel sleeve to form a whole through the spliced ribbed steel plate of the beam-column joint area, and the force is transmitted to the original structure, replacing the traditional embedded steel bar and forming a whole with the original structure. This has a positive significance for the reinforcement method of increasing the section, and can solve the problem that some projects cannot use the embedded steel bar method to increase the section. It is widely used in urban renewal projects.

[0034] (5) The cylindrical force transmission support for reinforcing the reinforced concrete frame beam-middle column joint with increased section and the reinforcing structure thereof can improve the rigidity and bearing capacity of the component, solve the problems of serious damage to the beam-column joint caused by punching and embedded steel bar, dense arrangement of embedded steel bars, and inability to use embedded steel bars for reinforcement of steel reinforced concrete columns, etc. The increased section reinforcement joint is simple to construct, has high safety, is green and environmentally friendly, and the spliced ribbed steel plate component can be processed in the factory, saving construction period. It is a new type of reinforced concrete frame beam-column joint reinforcement technology that is worth promoting and is widely used in urban renewal projects. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 : The three-dimensional assembly diagram of the cylindrical force transmission support for reinforcing the reinforced concrete frame beam-middle column joint with increased section of the application;

[0036] Figure 2 : Figure 1Schematic diagram of a closed cylindrical force-transmitting steel support;

[0037] Figure 3 : Figure 1 Structural plan view;

[0038] Figure 4 : Figure 1 A schematic diagram of spliced ​​ribbed steel plates;

[0039] Figure 5 : Figure 1 A three-dimensional schematic diagram of the installation of a closed cylindrical force-transmitting steel support;

[0040] Figure 6 : Figure 1 A schematic diagram showing the connection between the newly added longitudinal reinforcement and the steel sleeve.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1—Frame beam; 2—Frame column; 3—Closed cylindrical force-transmitting steel support; 4—Spliced ​​steel plate; 5—Triangular stiffening rib; 6—Spliced ​​ribbed steel plate; 7—Rebar sleeve; 8—Added longitudinal reinforcement; 9—Rebar cage; 10—Added concrete layer for beam; 11—Added concrete layer for column; 12—Upper "U" shaped steel support; 13—Lower "U" shaped steel support; 14—Vertical steel connector; 15—Concrete floor slab. Detailed Implementation

[0043] The following is combined with Figures 1 to 6 The present invention will be further described as follows:

[0044] A force-transfer bracket for increasing the cross-section of a reinforced concrete frame beam-column joint is provided. When increasing the cross-section of the original frame beam 1 and frame column 2, a closed cylindrical force-transfer steel bracket 3 is formed by welding and splicing ribbed steel plates 6 around the core area of ​​the joint, replacing the traditional drilling and rebar installation method. Concrete is poured on the outside of the bracket to form an increased cross-section structure in the beam-column joint area.

[0045] The composition and connection relationship of the components of this invention are as follows: Two spliced ​​steel plates 4 are welded vertically along their length. Triangular stiffening ribs 5 are placed inside the vertical spliced ​​steel plates 4 and welded at equal intervals along the length of the spliced ​​steel plates 4 to form spliced ​​ribbed steel plates 6. The spliced ​​ribbed steel plates 6 are in close contact with the horizontal members of the frame structure on the horizontal plane and in close contact with the side of the frame column 2 on the vertical plane. Adjacent spliced ​​ribbed steel plates 6 are welded around the frame column 2 to form an upper "U"-shaped steel bracket 12 and a lower "U"-shaped steel bracket 13. The closed cylindrical force-transmitting steel support 3 is composed of an upper "U"-shaped steel support 12, a lower "U"-shaped steel support 13, and a vertical steel connector 14 welded together. The upper "U"-shaped steel support 12 is arranged along the top of the concrete floor slab 15, and the lower "U"-shaped steel support 13 is arranged along the lower flange of the frame beam 1. The vertical steel connector 14 is arranged along the beam height direction. Its upper L-shaped cross-section is welded to the surface of the upper "U"-shaped steel support 12 steel plate that is close to the top of the concrete floor slab 15, and its lower L-shaped cross-section is welded to the surface of the lower "U"-shaped steel support 12 steel plate that is close to the lower flange of the frame beam 1, and is used to connect the upper "U"-shaped steel support 12 and the lower "U"-shaped steel support 13.

[0046] The closed cylindrical force-transfer steel support 3 serves to replace the traditional rebar anchoring method, connecting the newly added longitudinal reinforcement 6 to the original structure. A triangular opening, slightly larger than the cross-sectional dimensions of the vertical steel connector 14, is made in the core area of ​​the beam-column joint in the concrete floor slab 15, allowing the vertical steel connector 14 to pass through the floor slab and connect the upper "U"-shaped steel support 12 to the lower "U"-shaped steel support 13, forming the closed cylindrical force-transfer steel support 3. Rebar sleeves 7 are vertically welded to the surface of the spliced ​​steel plates 4 around the frame beam 1 and frame column 2. The newly added longitudinal reinforcement 8 is threadedly connected to the rebar sleeves 7 and tied with the rebar cage 9. The closed cylindrical force-transfer steel support 3 effectively encloses the original structural frame beam 1, frame column 2, and concrete floor slab 15 through the newly poured concrete, ensuring the reinforcement effect of the core area of ​​the beam-column joint and meeting the structural principle of "strong joint, weak component."

[0047] Both frame beam 1 and frame column 2 are reinforced concrete structures. The spliced ​​steel plate 4 is lightweight, consumes less material, saves costs, and occupies less space, while also offering greater construction flexibility. To prevent stress concentration at the ends of the steel plate and subsequent local buckling, triangular stiffening ribs 5, with a thickness equal to the steel plate thickness, are evenly spaced inside the welded spliced ​​steel plate 4 to improve the stiffness of the connector. These triangular stiffening ribs 5 are arranged at equal intervals of 100mm to 150mm, and each right-angled side is welded to the surface of the spliced ​​steel plate 4 by two vertical fillet welds. After welding the triangular stiffening ribs 5 onto two perpendicular spliced ​​steel plates 4, a spliced ​​ribbed steel plate 6 is formed. The hypotenuse of the triangular stiffening ribs 5 increases friction and improves bond strength during concrete pouring.

[0048] The upper "mouth" shaped steel support 12 is composed of the spliced ribbed steel plates 6 along the four sides of the frame column 2, and the length of the spliced ribbed steel plates 6 in each direction is determined by the length of the four sides of the frame column 2. The horizontal steel plate of the upper "mouth" shaped steel support 12 is tightly attached to the top of the concrete floor 15, and the corresponding position of the top of the plate can also be removed to make the subsequent poured concrete flush with the surrounding decorative layer. The vertical steel plate is tightly attached to the column wall of the frame column 2 located on the floor, and the L-shaped cross section of the spliced ribbed steel plate 6 along the outside of the column is welded to the adjacent spliced ribbed steel plate 6 through two vertical fillet welds. The adjacent spliced ribbed steel plates 6 welded are extended by 150mm-200mm from the edge of the column to form a wrapping constraint structure for the column, which ensures that the L-shaped cross section of the ribbed connecting piece on both sides can be connected by vertical fillet welding. At the same time, in order to facilitate the construction progress on site, three spliced ribbed steel plates 6 can be welded in advance in the factory according to the actual size of the frame column 2, directly fitted on the construction site, and then one spliced ribbed steel plate 6 is welded to form the upper "mouth" shaped steel support 12. The welding quality control level should be first or second.

[0049] The lower "mouth" shaped steel support 13 is composed of the spliced ribbed steel plates 6 along the four sides of the lower column of the frame beam 1, and the horizontal steel plate is tightly attached to the lower flange of the frame beam 1. The specific connection structure is the same as that of the upper "mouth" shaped steel support 12, which provides horizontal constraint for the original structure beam-column joint.

[0050] The closed cylindrical force transmission steel support 3 is a key component for reducing the damage structure of the reinforced concrete beam-column joint area, which is composed of the upper "mouth" shaped steel support 12, the lower "mouth" shaped steel support 13 and the vertical steel connecting piece 14.

[0051] The vertical steel connecting piece 14 is composed of two vertical spliced steel plates 4 tightly arranged along the vertical direction of the frame column 2, and the arrangement range is from the lower flange of the frame beam 2 to the height of the top of the concrete floor 15. The L-shaped cross section of the lower end of the vertical steel connecting piece 14 is welded to the top of the steel plate of the lower "mouth" shaped steel support 13 through two fillet welds. The upper "mouth" shaped steel support 12, the lower "mouth" shaped steel support 13 and the vertical steel connecting piece 14 form a cylindrical rigid force transmission support 3 by welding, which is used to wrap the core area of the beam-column joint, provide joint constraint and replace the traditional post-installed rebar method, connect the newly added longitudinal reinforcement 8 and the original structure, and the welding quality control level should be first or second.

[0052] When the frame column 2 is a special-shaped column, the relevant size of the spliced steel plate 4 is prepared in the factory according to the shape of the frame column 2 and the size of the original structure beam-column section obtained by on-site measurement, and the spliced ribbed steel plate 6 is formed by welding the stiffening rib by the construction personnel. After welding on the construction site, the closed cylindrical force transmission steel support 3 is formed, and the concrete is poured, and the principle is the same as above.

[0053] Based on the dimensions of the frame beam 1 and frame column 2 that need reinforcement, select appropriate splicing steel plates 4. Weld the long sides of two mutually perpendicular splicing steel plates 4. Arrange triangular stiffening ribs 5 at equal intervals along the length of the splicing steel plates 4. Among them, two right-angled sides are corner welded along the width of the splicing steel plates 4 to form splicing ribbed steel plates 6. This avoids stress concentration and local buckling at the connection between the splicing steel plates 4 and the original structural beam-column joint, and improves the stability and torsional resistance of the force transmission components.

[0054] In the reinforced beam-column joint area, the spliced ​​ribbed steel plate 6 is fixed to the concrete floor slab 15 around the original structural frame column 2 by welding and is located above the concrete floor slab 15, forming the upper "U"-shaped steel bracket 12. Similarly, the spliced ​​ribbed steel plate 6 is welded to the lower flange of the reinforced frame beam 1 around the original structural frame column 2, forming the lower "U"-shaped steel bracket 13. According to the L-shaped cross-sectional dimensions of the spliced ​​ribbed steel plate 6, the range of the floor slab opening at the beam-column intersection is determined. After chiseling out the triangular opening, the upper and lower ends of the L-shaped cross-section of the spliced ​​ribbed steel plate 6 are corner welded to the steel plate surfaces of the upper "U"-shaped steel bracket 12 and the lower "U"-shaped steel bracket 13 along the beam height range, so that the core area of ​​the beam-column joint is wrapped into a whole.

[0055] Based on the required number and location of longitudinal reinforcement bars for increasing the cross-section, the position of the reinforcement sleeve 7 is determined and welded perpendicularly to the splicing steel plate 4 along the direction of the reinforced frame beam 1 and the reinforced frame column 2. The newly added longitudinal reinforcement bar 8 is mechanically connected to the reinforcement sleeve 7 and fixed. The newly added longitudinal reinforcement bar 8 is then connected to the original structure through the closed cylindrical force-transfer steel bracket 3 to form a good force transmission path and improve the strength and bearing capacity of the original structure. Along the direction of the newly added longitudinal reinforcement bar 8, according to the actual calculation, the reinforcement cage 9 is tied at equal intervals. The formwork is erected and concrete is poured around the frame beam 1, frame column 2 and concrete floor slab 15 to complete the reinforcement, forming a cylindrical force-transfer bracket and its reinforcement structure for increasing the cross-section of reinforced concrete frame beam-column joint.

[0056] This invention relates to a cylindrical force-transfer bracket and its reinforcement structure for increasing the cross-section of a reinforced concrete frame beam-column joint. The specific implementation is as follows:

[0057] Step 1: Measure and lay out the lines around the reinforced frame beam 1 and the reinforced frame column 2 to determine the cross-sectional dimensions of the reinforced frame beam 1 and the reinforced frame column 2;

[0058] Step 2: Perform base treatment on the contact surfaces of frame beam 1 and frame column 2 to ensure a tight bond between the old and new concrete. Remove the concrete protective layer thickness from the concrete floor slab 15 around the frame column 2.

[0059] Step 3, splice ribbed steel plate 6 in the factory workshop processing. Purchased in advance corresponding to the size of the splice steel plate 4 and triangular stiffener 5, stiffener thickness equal to the splice steel plate 4 thickness, triangular stiffener 5 according to equal spacing 100 mm welded to the vertical two limbs of splice steel plate 4, form corresponding size splice ribbed steel plate 6;

[0060] Step 4, with the frame column 2 cross section size corresponding to the splice ribbed steel plate 6 horizontal splice steel plate 4 close to the frame column 2 around the four corners of the floor slab 15 board top, vertical splice steel plate 4 close to the frame column 2 column wall outside, with the column width of the same size of the splice ribbed steel plate 6 L shaped cross section perpendicular to the adjacent wider than the length of the column of the splice ribbed steel plate 6 out of the frame column 2 of the vertical steel plate side, form four edge closed upper "mouth" shape steel support 12;

[0061] Step 5, with the frame column 2 cross section size corresponding to the splice ribbed steel plate 6 close to the column vertical frame beam 1 lower flange, the rest is the same as step 5, form four edge closed lower "mouth" shape steel support 13;

[0062] Step 6, determine the concrete floor 15 opening position and range. The floor slab at the intersection of frame beam 1 and frame column 2 is slightly larger than the triangular hole of the L shaped cross section of the vertical splice steel plate 4;

[0063] Step 7, the splice ribbed steel plate 6 with a height of frame beam 1 beam bottom to the top of the concrete floor 15 is arranged along the column direction, passing through the floor hole, the upper and lower ends of the L shaped cross section are vertically welded on the horizontal steel plate of the upper "mouth" shape steel support 12 and the lower "mouth" shape steel support 13, forming the closed cylindrical force transmission steel support 3, which tightly wraps the original structure beam column joint core area;

[0064] Step 8, weld the steel bar sleeve 7 to the corresponding position of the splice ribbed steel plate 6. According to the number and position of the newly added stress longitudinal reinforcement required for increasing the cross section, weld the steel bar sleeve 7 at the corresponding position of the steel plate.

[0065] Step 9, the newly added longitudinal reinforcement 8 is screwed into the inside of the steel bar sleeve 7 and is threadedly connected with the steel bar sleeve 7, and is fixed on the surface of the closed cylindrical force transmission steel support 3.

[0066] Step 10, the steel cage 9 is respectively bound on the outer side of the newly added longitudinal reinforcement 8 along the frame beam 1 and the frame column 2 direction with equal spacing.

[0067] Step 11, the closed cylindrical force transmission steel support 3 at the beam column joint core area is bound with the formwork, and the self compacting concrete is poured along the steel plate at the frame beam 1, frame column 2 and concrete floor 15, respectively forming the beam newly added concrete layer 10 and the column newly added concrete layer 11.

[0068] Step 12, curing the concrete, after removing the formwork to form the reinforcing structure of the cylindrical force transfer support for the reinforced concrete frame beam-column joint section enlargement reinforcement.

[0069] The application is described above by way of example with reference to the accompanying drawings without limitation to the described embodiments. Any modifications of the application conceived on the basis of the teaching provided herein or any direct applications of the application's concept and technology to other fields are to be considered within the scope of the application.

Claims

1. A force transfer support for reinforced concrete frame beam-column joint section augmented reinforcement, characterized in that: A closed cylindrical force transmission steel support (3) is arranged at the connection between the frame beam (1) and the frame column (2), and the closed cylindrical force transmission steel support (3) penetrates the concrete floor (15); the closed cylindrical force transmission steel support (3) is composed of an upper "mouth" shaped steel support (12), a lower "mouth" shaped steel support (13) and a vertical steel connecting piece (14); wherein the upper "mouth" shaped steel support (12) is arranged above the concrete floor (15) and along the top of the concrete floor (15), the lower "mouth" shaped steel support (13) is arranged below the concrete floor (15) and along the lower flange of the frame beam (1); the vertical steel connecting piece (14) is arranged along the beam height direction, the upper end is close to the surface of the steel plate of the upper "mouth" shaped steel support (12), and the lower end is close to the surface of the steel plate of the lower "mouth" shaped steel support (13); the upper "mouth" shaped steel support (12) and the lower "mouth" shaped steel support (13) are both composed of a plurality of spliced ribbed steel plates (6); the horizontal surface of the spliced ribbed steel plate (6) is close to the top of the concrete floor (15) and the lower flange of the frame beam (1), and the vertical surface is close to the side surface of the frame column (2), the adjacent spliced ribbed steel plates (6) are surrounded around the frame column (2) by welding, and the upper "mouth" shaped steel support (12) and the lower "mouth" shaped steel support (13) are formed.

2. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column joints according to claim 1, characterized in that: Each spliced ribbed steel plate (6) comprises two spliced steel plates (4) which are vertically welded along the length direction, and a plurality of triangular stiffening ribs (5) which are welded along the length direction of the spliced steel plate (4) at equal intervals to improve the rigidity of the connecting piece, so as to form the spliced ribbed steel plate (6).

3. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column joints according to claim 2, characterized in that: The concrete floor (15) is provided with a triangular hole at the beam-column joint core area, the size of the hole is slightly larger than the cross-sectional size of the vertical steel connecting piece (14), so that the vertical steel connecting piece (14) can penetrate the concrete floor (15); the vertical steel connecting piece (14) is arranged vertically by two spliced steel plates (4) close to the frame column (2), and the arrangement range is from the lower flange of the frame beam (1) to the top of the concrete floor (15).

4. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column joints according to claim 3, characterized in that: The two spliced steel plates (4) of each vertical steel connecting piece (14) are vertically welded along the length direction, and a plurality of triangular stiffening ribs (5) are arranged inside the vertical spliced steel plates (4) and welded along the length direction of the spliced steel plate (4) at equal intervals to improve the rigidity of the connecting piece.

5. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column joints according to claim 4, characterized in that: The upper end of the vertical steel connecting piece (14) is L-shaped in cross section and is welded to the surface of the steel plate of the upper "mouth" shaped steel support (12) close to the top of the concrete floor (15), and the lower end of the vertical steel connecting piece (14) is L-shaped in cross section and is welded to the surface of the steel plate of the lower "mouth" shaped steel support (13) close to the lower flange of the frame beam (1).

6. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column joints according to claim 5, characterized in that: The steel sleeve (7) is vertically welded to the surface of the spliced steel plate (4) around the frame beam (1) and the frame column (2), the new longitudinal reinforcement (8) is screwed with the steel sleeve (7), and the steel reinforcement cage (9) is bound; the closed cylindrical force transmission steel support (3) is effectively wrapped with the original structure frame beam (1), frame column (2) and concrete floor (15) through newly poured concrete.

7. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column nodes according to claim 6, characterized in that: The internal of the steel bar sleeve (7) is provided with an internal thread structure. One end of the steel bar sleeve (7) is vertically welded and fixed on the steel plate surface of the closed cylindrical force-transferring steel support (3), and the other end is threadedly connected to the newly added longitudinal bar (8). The newly added longitudinal bar (8) is provided with an external thread structure, and the steel reinforcement cage (9) is evenly tied along the length of the newly added longitudinal bar (8).

8. The load bearer for section augmented reinforcement of reinforced concrete frame beam-column joints according to claim 7, characterized in that: After pouring self-leveling, slightly expanding concrete around the closed cylindrical force-transferring steel support (3) and the periphery of the newly added longitudinal bar (8), a newly added concrete layer (10) of the beam and a newly added concrete layer (11) of the column are formed.

9. A manufacturing method of a cylindrical force-transferring support for enlarging the cross-section of a reinforced concrete frame beam-middle column joint, comprising the following steps: Step 1: Measure and set out the lines around the reinforced frame beam (1) and the reinforced frame column (2) to determine the cross-sectional dimensions of the reinforced frame beam (1) and the reinforced frame column (2). Step 2: Conduct base treatment on the contact surfaces of the frame beam (1) and the frame column (2) to ensure close bonding between the new and old concretes. Remove the concrete protective layer thickness along the four sides of the concrete floor slab (15) around the frame column (2). Step 3: The thickness of the triangular stiffening rib (5) is equal to the thickness of the splicing steel plate (4). The triangular stiffening rib (5) is welded to the two vertical limbs of the splicing steel plate (4) at equal intervals to form a splicing ribbed steel plate (6) with corresponding dimensions. Step 4: The horizontal splicing steel plate (4) of the splicing ribbed steel plate (6) corresponding to the cross-sectional dimension of the frame column (2) is closely attached to the top of the concrete floor slab (15) with the protective layer thickness chiseled around the frame column (2). The vertical splicing steel plate (4) is closely attached to the outer side of the column wall of the frame column (2). The L-shaped cross-section of the splicing ribbed steel plate (6) with the same width as the column is perpendicularly welded to one side of the vertical steel plate of the adjacent splicing ribbed steel plate (6) wider than the column length and extending out of the frame column (2), forming an upper "mouth"-shaped steel support (12) with four sides closed. Step 5: The splicing ribbed steel plate (6) corresponding to the cross-sectional dimension of the frame column (2) is closely attached to the lower flange of the frame beam (1) perpendicular to the column, forming a lower "mouth"-shaped steel support (13) with four sides closed. Step 6: Determine the opening position and range of the concrete floor slab (15). The chiseled size of the floor slab at the intersection of the frame beam (1) and the frame column (2) is slightly larger than the triangular hole of the L-shaped cross-section of the vertical splicing steel plate (4). Step 7: The splicing ribbed steel plate (6) with a height from the bottom of the frame beam (1) to the top of the concrete floor slab (15) is arranged along the column direction, passes through the floor hole, and the upper and lower ends of the L-shaped cross-section are perpendicularly welded to the horizontal steel plates of the upper "mouth"-shaped steel support (12) and the lower "mouth"-shaped steel support (13), forming a closed cylindrical force-transferring steel support (3) that tightly wraps the core area of the original structural beam-column joint. Step 8: Weld the steel bar sleeve (7) to the corresponding position of the splicing ribbed steel plate (6). According to the number and position of the newly added stressed longitudinal bars required for enlarging the cross-section reinforcement, vertically weld the steel bar sleeve (7) at the corresponding position of the steel plate. Step 9, add longitudinal reinforcement (8) screw into the steel sleeve (7) inside, with steel sleeve (7) threaded connection, fixed on the surface of the closed cylindrical force steel support (3); Step 10, steel cage (9) along the required increase in cross section of frame beam (1) and frame column (2) direction equal interval binding on the outside of the new longitudinal reinforcement (8); Step 11, beam column joint core area closed cylindrical force steel support (3) peripheral binding formwork, along the frame beam (1), frame column (2) and concrete floor (15) at the steel plate pouring self-compacting concrete, respectively form beam new concrete layer (10) and column new concrete layer (11); Step 12, maintenance of concrete, after removing the formwork to form a steel reinforced concrete frame beam-column node for increasing cross section reinforcement of cylindrical force support and its reinforcement structure.

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