A new type of beam-column joint of reinforced concrete structure and construction method

Abstract

The present invention provides a novel beam-column joint of a reinforced concrete structure, which comprises a core area of the beam-column joint and a reinforced concrete ring beam, wherein the reinforced concrete ring beam is arranged around the core area of the beam-column joint. The core area of the beam-column joint includes the main reinforcement passing through the core area in the frame column, as well as stirrups, additional stirrups, steel plate sleeves, concrete, etc. in the core area. The stirrups are tied outside the main reinforcement, and the steel plate sleeves outside the stirrups are supported on the bottom reinforcement of the frame beam passing through the core area; by adopting steel strips to replace some stirrups, reducing the stirrup spacing, improving construction measures, etc., a space with a diameter of about 200 mm is vacated in the center of the core area of the joint to provide an operating space for the binding and installation of reinforcement; at the same time, it is convenient for the insertion and extraction of vibrating rods, making it possible to vibrate the concrete densely. The concrete in the core area of the joint within the closed area of the steel plate sleeve can be poured simultaneously with the lower column, which can easily solve the problem of pouring the concrete in the core area when the concrete strength of the column is higher than that of the beam and slab.

Description

Technical Field

[0001] The invention relates to the technical field of building structure engineering, in particular to a novel reinforced concrete structure beam-column node and a construction method. Background Art

[0002] The quality of construction projects is closely related to the safety of buildings, the safety of people's lives and property, social harmony, and stability. Therefore, the construction authorities have always attached great importance to the quality management of construction projects. In recent years, with the continuous increase in the supervision of construction project quality, the overall level of construction quality has steadily improved. However, in the process of house construction in my country, many common problems in construction quality still lack effective solutions.

[0003] The beam-column joint is the key part of the reinforced concrete frame structure and the hub connecting the structural system. It plays a connecting role. From the perspective of force, the stress situation in the core area of ​​the beam-column joint is relatively complex. It not only directly bears the pressure, shear force and bending moment from the frame column end, but also bears the shear force and bending moment at the beam end. When the earthquake is repeated, the core concrete is in a complex shear-compression stress state, which often causes cross cracks in the core area and column end compression, peeling, steel bar buckling and bulging. In particular, the corner columns and side columns are more complex due to the influence of factors such as torsion and eccentricity, and are more likely to cause earthquake damage than the inner frame columns. Previous earthquake damages have shown that the parts of the frame structure that are severely damaged by earthquakes mostly occur at the beam-column joints where the force is the most complex. The destruction of the frame structure is mostly caused by insufficient strength and ductility of the concrete in the core area of ​​the beam-column joint. Therefore, the beam-column joint is the weak link in the quality of the concrete structure. The beam-column joint with reliable quality is the basic guarantee for ensuring the safe service of the structural system.

[0004] Investigations and analyses have shown that it is particularly common to find insufficient or missing stirrups at the joints of reinforced concrete beams and columns, or stirrups not being placed according to the design spacing requirements, or main reinforcement not being bent and anchored in place. Loose concrete and voids inside the nodes also occur from time to time, which seriously affects the quality of the structure.

[0005] The industry is not surprised by the problems existing in the construction of beam-column joints of reinforced concrete structures. The industry believes that although the relevant specifications have detailed provisions, due to the large number of steel bars in the beam-column joint area, especially the dense steel bars at the nodes of the middle columns: ① In the vertical direction, the longitudinal steel bars of the frame column pass through the core area of ​​the node; ② In the horizontal direction, the load-bearing steel bars of the longitudinal and transverse frame beams all pass through or are anchored on the inner side of the longitudinal steel bars of the frame column, forming a three-dimensional cross-section in the shape of a tic-tac-toe; ③ In addition, there are transverse stirrups tied to the main bars, etc.

[0006] For operators who mainly perform manual work, it is extremely difficult to complete the steel bar project that fully complies with the specifications by carrying out steel bar tying operations in a small space.

[0007] In summary, the main reason for the difficulty in binding steel bars is that the steel bars in the beam-column joint area of the reinforced concrete structure are too concentrated vertically and horizontally. This is also the main reason why the vibrating rod is difficult to insert, the concrete vibration is not in place, resulting in insufficient compactness of the concrete in the joint area and the difficulty in ensuring the construction quality of the beam-column joint.

[0008] In addition, in actual engineering, it is often encountered that the designed strength grade of the frame column concrete is two grades or more higher than that of the beam and slab concrete. In this regard, the "Code for Construction of Concrete Structures" GB50666 and the "Code for Acceptance of Construction Quality of Concrete Structures" GB50204 both have clear regulations that separation measures should be taken in the junction area.

[0009] At present, the following two methods are mainly used in engineering to solve this problem. First, increase the strength grade of the beam and slab concrete so that the strength grade difference between the beam and column concrete is not higher than 5 Mpa. After obtaining the consent of the design unit, pour the concrete with the same designed strength grade as that of the beam and slab concrete. Using this method will inevitably increase the project cost significantly.

[0010] Second, at a distance of 500 mm from the column edge and not less than 1 / 2 of the height of the frame beam, separate the concrete with different strength grades along a 45-degree inclined plane from the beam top to the beam bottom with a wire mesh sheet, and first pour the concrete of the frame column. This is feasible in theory, but in actual engineering, due to the need for pumping, the slump of the commercial concrete is relatively large, generally 180 - 220 mm. Therefore, it is very difficult to operate in actual engineering. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a new type of beam-column joint of a reinforced concrete structure, which has the advantages of relatively dispersed steel bar arrangement in the core area, facilitating the binding and installation of steel bars, the insertion of vibrating rods and the vibration of concrete in the core area of the beam-column joint, and controllable construction quality.

[0012] The present invention is realized as follows: A new type of beam-column joint of a reinforced concrete structure includes

[0013] The core area of the beam-column joint where the frame beam and the frame column intersect; the core area of the beam-column joint includes the main steel bars passing through the core area of the beam-column joint in the frame column, the stirrups in the core area, the additional stirrups, the steel plate sleeve welded together, and the concrete; the stirrups are bound outside the main steel bars, the steel plate sleeve is sleeved outside the stirrups, and the steel plate sleeve also supports on the main steel bars at the bottom of the frame beam crossing the core area;

[0014] A reinforced concrete ring beam, which surrounds the core area of the beam-column joint.

[0015] Furthermore, the concrete strength of the reinforced concrete ring beam is the same as that of the beam-slab, and the height of the ring beam ≥ the height of the frame beam + 50 mm; the width of the reinforced concrete ring beam ≥ the width of the frame beam, and it should be able to meet the anchorage requirements of the main reinforcement of the frame beam. The anchorage of the main reinforcement of the frame beam in the ring beam shall be carried out in accordance with the provisions of GB50010.

[0016] Furthermore, the diameter of the main reinforcement of the reinforced concrete ring beam ≥ B16, and the spacing ≤ 200 mm; when the web height of the ring beam ≥ 450 mm, longitudinal structural reinforcement bars (waist bars) shall be arranged along the height on both sides of the ring beam, with a diameter ≥ B14, the spacing of each side of the longitudinal structural reinforcement bars ≤ 200 mm, and the spacing of the stirrups between the waist bars ≤ 200 mm; both the main reinforcement and the waist bars adopt welded joints. The diameter of the configured stirrups ≥ A8, and the spacing ≤ 100 mm.

[0017] Furthermore, measures such as using steel plate sleeves to replace some stirrups, appropriately reducing the stirrup spacing, and optimizing the structural scheme of the joint core area are taken in the core area of the beam-column joint. On the premise that the stirrup limb distance meets the requirements of the "Code for Seismic Design of Buildings" GB50011, the stirrups are installed avoiding the middle part in the core area, ensuring that there are no steel bars and stirrups passing through the middle part within a range with a diameter of approximately 200 mm in the cross-section of the core area of the reinforced concrete beam-column joint, so that the vibrating rod can be inserted and pulled out without obstruction.

[0018] Furthermore, the steel plate sleeve is welded by four steel plates, and the steel plate sleeve is welded with full penetration welds throughout the whole height; the height of the steel plate sleeve = the clear distance between the bottom reinforcement of the frame beam passing through the core area and the top reinforcement of the beam passing through the core area - 10 mm.

[0019] Furthermore, the corner bars of the two-way frame beam and the beam side bars located in the second row cross the core area, forming an integral whole with the reinforced concrete ring beam to enhance the ability of the core area to resist damage; for the border joints, the beam side bars located in the 1st - 2nd rows of the frame beam pass through the core area of the reinforced concrete beam-column joint and are anchored in the ring beam on the other side; while the non-beam side bars and the bars in the 3rd row and above in the frame beam completely pass through the reinforced concrete ring beam on the same side and then are bent and anchored, providing convenience for the influence of the vibrating rod to reach every corner.

[0020] Furthermore, when the column section changes, the main reinforcement of the lower column extends to the top of the steel plate sleeve and then is bent and anchored in the ring beam on the same side, and its total anchorage length ≥ 1.2 l aE, and the anchorage length of the horizontal section ≥ 12d; the main reinforcement of the upper column extends to the bottom of the steel plate sleeve and then is bent and anchored in the ring beam on the same side, and its total anchorage length ≥ 1.2 l aE, and the anchorage length of the horizontal section ≥ 12d, where d is the diameter of the main reinforcement, l aE is the anchorage length of the tensioned reinforcement during earthquake.

[0021] Furthermore, at the top-level node, the main reinforcement bars of the lower column extend to the top of the steel plate sleeve and then bend and are anchored into the ring beam on the same side, with the total anchorage length ≥ 1.2 l aE, and the anchorage length of the horizontal section ≥ 12d.

[0022] Furthermore, at the positions corresponding to the frame beam surface and the beam bottom in the core area of the beam-column joint, stirrups with a diameter ≥ B12 are welded respectively.

[0023] Furthermore, measures such as increasing the stirrup diameter and appropriately reducing the stirrup spacing are taken in the frame column. On the premise that the stirrup limb distance meets the requirements of the "Code for Seismic Design of Buildings" GB50011, the stirrups are installed avoiding the middle part with a diameter of about 200mm in the core area to facilitate the vibration rod to play its role.

[0024] If the frame column still cannot meet the shear bearing capacity requirements, a steel plate sleeve welded by steel strips can also be used to replace some stirrups in the frame column. The steel plate sleeve in the frame column is also welded by four steel plates. The steel plate sleeve in the frame column uses full penetration welds within the range of H n / 3 at the lower end of the bottom column, uses full penetration welds within the range of Sc at the upper end of the bottom column, and can use partial penetration welds in the middle part; the height of the steel plate sleeve of the bottom column = the distance from the bottom of the second-floor frame beam to the top surface of the foundation - 10mm.

[0025] The steel plate sleeve in the frame column uses full penetration welds within the range of Sc at both ends of other floors, and can use partial penetration welds in the middle part, where Sc ≥ h c Sc ≥ H n / 6, and Sc ≥ 500mm, h c is the long side dimension of the cross-section of the frame column, and H n is the clear height of the frame column; the height of the steel plate sleeve in the frame column = the distance from the bottom of the upper-layer frame beam to the floor of the next lower layer - 10mm.

[0026] The present invention has the following advantages:

[0027] (1) A reinforced concrete ring beam is arranged around the core area of the beam-column joint. The corner bars and the beam side bars in the second row in the frame beam pass through the core area and form an integral body with the reinforced concrete ring beam, enhancing the ability of the core area to resist damage; while the non-beam side bars in the 1st to 2nd rows and the bars in the third row and above in the frame beam completely pass through the reinforced concrete ring beam on the same side and then bend and are anchored; at the top-level node, the main reinforcement bars of the frame column are bent into the ring beam on the same side for anchorage, thus avoiding the situation of crisscrossing of steel bars in the core area of the node, providing a necessary operating space for steel bar binding and installation, and providing a necessary guarantee for improving the binding quality of steel bars in the core area of the beam-column joint.

[0028] (2) In the core area of beam-column joints, measures such as using steel plate sleeves welded by steel strips to replace some stirrups, appropriately reducing the stirrup spacing, and optimizing the construction plan for the core area of the joints are taken to further improve the condition of dense steel bars in the core area of the joints; on the premise that the stirrup limb distance meets the requirements of the Code for Seismic Design of Buildings GB50011, the stirrups are installed avoiding the middle part in the core area to ensure that there are no stirrups, main bars, etc. passing through the middle part within a range of approximately 200 mm in diameter in the cross-section of the core area of reinforced concrete beam-column joints, which is convenient for the insertion and extraction of vibrating rods, ensuring that the action effect of the vibrating rods is transmitted to every part in the core area, enabling the concrete to be effectively vibrated and the air bubbles in the concrete to be removed in time, which can effectively improve the compactness of the concrete and increase the strength of the concrete.

[0029] (3) On the premise of facilitating construction, appropriately reducing the stirrup spacing in the core area of the joints, combined with the effect of the steel plate sleeve restricting the concrete, can greatly enhance the deformation capacity of the core area and improve the seismic performance of the structure; the concrete in the core area is restricted by the steel plate sleeve around it, which can avoid the risk of high-strength concrete bursting at high temperatures in case of fire emergencies.

[0030] (4) In the novel reinforced concrete beam-column joint described, the steel plate sleeve sleeved outside the stirrups surrounds the core area of the beam-column joint to form a relatively enclosed area, which can separate the concrete in different areas, that is, separate the concrete in the core area from the concrete in the frame beam. Therefore, by using the novel reinforced concrete beam-column joint, the construction difficulty when the concrete strength in the core area of the frame joint is higher than that of the beam and slab concrete can be easily solved.

[0031] (5) The implementation of the novel reinforced concrete beam-column joint can provide necessary guarantee for the realization of the design concept of "strong columns and weak beams, and even stronger joints". Description of the Drawings

[0032] The present invention will be further described below with reference to the drawings in conjunction with embodiments.

[0033] Figure 1 It is a schematic diagram of the novel reinforced concrete frame structure described in the present invention.

[0034] Wherein, Sc≥h c , Sc≥H n / 6, and Sc≥500 mm, h c is the long side dimension of the cross-section of the frame column, H nis the net height of the frame column; S is the length of the beam end stirrup reinforcement zone. When the seismic resistance level is level one, the length of the beam end stirrup reinforcement zone S≥2.0hb (hb is the beam height) and not less than 500mm; when the seismic resistance level is level two to four, the length of the beam end stirrup reinforcement zone S≥1.5hb (hb is the frame beam height) and not less than 500mm. H1, H2, Hw are the structural elevations of the 2nd, 3rd and roof layers respectively.

[0035] Figure 2 It is a plan view of the new reinforced concrete structure beam-column node described in the present invention.

[0036] Figure 3 It is an elevation view of the new reinforced concrete structure beam-column node described in the present invention.

[0037] Figure 4 It is a schematic diagram of the relative position relationship between the main reinforcement of the frame beam and the main reinforcement of the reinforced concrete core area in the plane.

[0038] Figure 5 for Figure 4 The AA section diagram is also a diagram of the vertical relative position relationship between the steel plate sleeve and the main reinforcement of the frame beam.

[0039] Figure 6 for Figure 5 Schematic diagram of reinforcement of the middle BB section.

[0040] Among them, b is the width of the frame beam and hb is the height of the frame beam.

[0041] Figure 7 Schematic diagram of the reinforcement of the reinforced concrete core section Figure 1 .

[0042] Figure 8 Schematic diagram of the reinforcement of the reinforced concrete core section Figure 2 .

[0043] Figure 9 Schematic diagram of the reinforcement of the reinforced concrete core section Figure 3 .

[0044] Figure 10 for Figure 9 Schematic diagram of the reinforcement in the core area of ​​the CC section.

[0045] Figure 11 It is a schematic diagram of the structure of the steel plate sleeve 32 formed by welding steel plate strips.

[0046] Among them, the index number of the arrow tail in the weld marking can be found in Appendix A of the national standard drawing set 15G909-1 (the same as the rest).

[0047] Figure 12It is a schematic diagram of the anchorage structure of the main bars of a frame column in the joint core area when the cross-section of the reinforced concrete frame column changes.

[0048] Where d is the diameter of the steel bar.

[0049] Figure 13 It is a schematic diagram of the anchorage of the main bars of a reinforced concrete frame column at the top floor side joint.

[0050] Where d is the diameter of the steel bar.

[0051] Figure 14 It is a reinforcement bar layout diagram of the reinforced concrete ring beam described in the present invention.

[0052] Where bc is the width of the frame column and hc is the cross-sectional height of the frame column.

[0053] Figure 15 It is a detailed drawing of the main bars of the reinforced concrete ring beam described in the present invention.

[0054] Figure 16 It is Figure 14 The cross-sectional view of the reinforced concrete ring beam located on the left side of the joint core area in

[0055] Figure 17 It is the reinforcement bar layout plan of the reinforced concrete ring beam at the middle layer corner joint.

[0056] Where bc is the width of the frame column and hc is the cross-sectional height of the frame column.

[0057] Figure 18 It is the reinforcement bar layout plan of the reinforced concrete ring beam at the middle layer side joint.

[0058] Where bc is the width of the frame column and hc is the cross-sectional height of the frame column.

[0059] Figure 19 It is a schematic diagram of the anchorage of the main bars of a middle layer reinforced concrete frame beam in the side joint core area.

[0060] Figure 20 It is a schematic diagram of the anchorage of the main bars of a reinforced concrete frame beam in the top floor side joint core area.

[0061] Figure 21 And 22 They are respectively schematic diagrams of the anchorage structures of the main bars of a frame beam in the joint core area when the cross-sectional heights of the reinforced concrete frame beams are different.

[0062] Where HE is the height difference between the bottom main bars of the frame beams on both sides of the core area, and Bhu is the width of the ring beam.

[0063] Figure 23 It is a schematic diagram of a frame column, where Sc is the length of the column end encrypted area;

[0064] Figures 24 - 26 It is a schematic diagram of the sectional reinforcement of a reinforced concrete frame column, where bc and hc are the short side and long side dimensions of the frame column respectively.

[0065] Figure 27 It is a schematic diagram of the structure when the steel plate sleeve 42 adopts a full-penetration weld.

[0066] Figure 28 It is a schematic diagram of the structure when the steel plate sleeve 42 adopts a partial-penetration weld.

[0067] Among them, for the index number at the arrow tail in the weld mark, see Appendix A of the national standard atlas 15G909-1 (the same hereinafter).

[0068] Explanation of reference numerals:

[0069] Reinforced concrete ring beam 1, main reinforcements 11, 12, 13, stirrups 14, waist reinforcements on the side of the beam 15, tie bars 16, see Figure 16 ;

[0070] Frame beam 2, bottom corner reinforcements 21, second row of main reinforcements on the side of the beam at the bottom of the beam 22, other main reinforcements at the bottom 23, stirrups 24, top corner reinforcements 25, second row of main reinforcements on the side of the beam at the top of the beam 26, other main reinforcements at the top of the beam 27; waist reinforcements 28, tie bars 29, see Figures 4 - 6 ;

[0071] Beam-column joint core area 3, main reinforcements 31, main reinforcements of the lower column 311, main reinforcements of the upper column 312, steel plate sleeve 32 in the core area, stirrups 33, additional stirrups 331, 332, see Figure 5 、 Figures 8 - 12 ;

[0072] Frame column 4, stirrups 41, steel plate sleeve 42 on the column body, see Figures 23 - 28 ; ;

[0073] Foundation 5. Detailed implementation manners

[0074] The inventive concept of the present invention is as follows:

[0075] (1) A reinforced concrete ring beam is arranged around the beam-column joint core area. The main reinforcements on the side of the frame beam that have little influence on the operation of the vibrating rod when extending into the core area are passed through the core area and form an integral body with the reinforced concrete ring beam to enhance the ability of the core area to resist damage; while the beam-column steel bars that pass through or are anchored in the core area and will prevent the vibrating rod from being inserted and pulled out are anchored in the reinforced concrete ring beam on the same side, thus avoiding the situation where the steel bars in the node core area are crisscrossed, providing a necessary operating space for steel bar binding and installation, and providing a necessary guarantee for improving the binding quality of the steel bars in the beam-column joint core area.

[0076] (2) In the core area of the beam-column joint and within the frame column, measures such as using steel plate sleeves to replace some stirrups, appropriately reducing the spacing of stirrups in the core area, and optimizing the steel bar layout plan are taken to further improve the condition of dense steel bars in the core area of the joint. On the premise that the limb distance of the stirrups meets the requirements of the Code for Seismic Design of Buildings GB50011, the stirrups are installed avoiding the middle part of about 200 mm in the core area, ensuring that there are no steel bars and stirrups passing through the middle part with a diameter of about 200 mm in the cross-section of the frame column and the core area of the reinforced concrete beam-column joint, which is convenient for the insertion and extraction of the vibrating rod, ensuring that the action effect of the vibrating rod is transmitted to every part in the core area, enabling the concrete to be effectively vibrated, timely removing the air bubbles in the concrete, and effectively improving the compactness of the concrete and increasing the strength of the concrete.

[0077] (3) In the novel reinforced concrete beam-column joint described above, the core area of the beam-column joint is surrounded by steel plate sleeves welded together. The steel plate sleeves separate the concrete in different areas, that is, separate the concrete in the core area from the concrete of the beam, and can pour the concrete simultaneously with the lower column. Therefore, by using the novel reinforced concrete beam-column joint, the pouring problem of the concrete in the core area of the beam-column joint can be effectively solved when the design strength of the concrete of the lower column is two grades or more higher than the design strength of the concrete of the beam slab, ensuring that the concrete strength grade in the core area of the joint is the same as that of the lower column.

[0078] Please refer to Figures 1 to 28 as shown. Embodiment

[0079] A novel reinforced concrete beam-column joint of the present invention includes

[0080] (1) The core area 3 of the beam-column joint where the frame beam 2 and the frame column 4 intersect, as Figures 1 - 11 shown. The core area 3 of the beam-column joint includes the main steel bars 31 passing through the core area 3 of the beam-column joint in the frame column 4, the concrete in the core area, the steel plate sleeve 32 and the stirrups 33, as well as the additional stirrups 331, 332, for details see Figure 5 and Figure 10 shown; when the cross-section of the column changes, it also includes the main steel bars 311 of the lower column and the main steel bars 312 of the upper column, for details see Figure 12 shown; the stirrups 33 are tied outside the main steel bars 31 and the main steel bars 311 of the lower column, and then the steel plate sleeve 32 is sleeved outside the stirrups 33 and supported on the second row of beam side main steel bars 22 passing through the core area in the two-way frame beam 2, where the second row of beam side main steel bars 22 is located on the side of the second row at the bottom of the frame beam and is fixed to the main steel bars in the core area by tying or by welding with short steel bars, for details see Figure 4 and Figure 5 shown.

[0081] In a specific embodiment, the spacing of the stirrups 33 in the core area is ≤ 100 mm. Under the condition of meeting the operating conditions, the spacing should be as small as possible, generally taking 50 - 100 mm; the limb distance of the stirrups 33 near the middle of the core area 3 of the beam-column joint should be ≥ 200 mm and should comply with the provisions of the national standard "Code for Seismic Design of Buildings" GB50011; the stirrups 33 can be in the form shown as Figures 7 - 9 etc. In the middle part of the core area, stirrup ties should be avoided to ensure that there are no stirrups, main reinforcements, etc. passing through within a range with a center diameter of approximately 200 mm in the core area 3 of the beam-column joint, as shown by the dashed circle in Figures 7 - 9 . This is convenient for the insertion and extraction of the vibrating rod, ensuring that each part of the concrete in the core area is within the effective radius of the vibration effect, enabling the concrete to be effectively vibrated, promptly removing the air bubbles in the concrete, effectively improving the compactness of the concrete, and enhancing the strength of the concrete.

[0082] The steel plate sleeve 32 in the core area is welded by four steel plates, and its detailed drawing is shown in Figure 11 ; Full penetration welds are used for welding within the full height of the steel plate sleeve. The weld markings shall be carried out in accordance with the national standard design atlas "Construction Drawings of Steel Structure Connections" 15G909 - 1. The height of the steel plate sleeve = the clear distance between the bottom reinforcement of the frame beam passing through the core area and the top reinforcement of the beam passing through the core area - 10 mm; where t1 and t2 are the thicknesses of the steel plate strips on two opposite sides respectively. The calculation of the strength, thickness of the steel plate and the shear bearing capacity of the joint shall be carried out in accordance with the current national standards "Loads on Building Structures" GB50009, "Code for Design of Concrete Structures" GB50010, "Standard for Design of Steel Structures" GB50017, "Technical Specification for Concrete-Filled Steel Tube Structures" GB50936, "Technical Specification for Concrete Structures of High-Rise Buildings" JGJ3, "Technical Specification for Steel Structures of High-Rise Civil Buildings" JGJ99 and the provisions of the China Engineering Construction Standard Association "Technical Specification for Rectangular Concrete-Filled Steel Tube Joints", etc.; For frame structures with seismic design, it shall also comply with the provisions of the current national standard "Code for Seismic Design of Buildings" GB50011.

[0083] Reinforcing stirrups 331 are provided at the corresponding positions outside the main reinforcements 31 in the core area or the main reinforcements 311 of the lower column opposite to the bottom of the frame beam, and reinforcing stirrups 332 are provided at the corresponding positions outside the main reinforcements 31 in the core area or the main reinforcements 312 of the upper column opposite to the top of the frame beam, as shown in Figure 12 .

[0084] When the cross-sectional dimensions of the upper and lower columns are different, the main reinforcements 311 of the lower column extend to the top of the steel plate sleeve and then are bent and anchored into the ring beam on the same side, and the total anchorage length ≥ 1.2 l aE, and the anchorage length of the horizontal section ≥ 12d; the main reinforcements 312 of the upper column extend to the bottom of the steel plate sleeve and then are bent and anchored into the ring beam on the same side, and the total anchorage length ≥ 1.2 laE, the anchorage length of the horizontal section ≥ 12d, where d is the diameter of the main reinforcement bar. l aE is the anchorage length of the tension reinforcement bar during seismic design. The schematic diagram is shown in Figure 12 .

[0085] At the top floor node, the main reinforcement bars 311 of the lower column extend to the top of the steel plate sleeve and then bend and are anchored into the ring beam on the same side. The total anchorage length ≥ 1.2 l aE, and the anchorage length of the horizontal section ≥ 12d. For details, see Figure 13 .

[0086] (2) Reinforced concrete ring beam 1, which is sleeved outside the core area 3 of the beam-column joint, as Figures 14 - 18 shown. In a specific implementation, the strength grade of the reinforced concrete ring beam 1 is the same as that of the frame beam and is cast integrally with the beam slab.

[0087] In the novel reinforced concrete beam-column joint of the present invention, a reinforced concrete ring beam 1 is arranged around the core area 3 of the beam-column joint. The bottom corner bars 21, the top corner bars 25, the second-row side main reinforcement bars 22 at the bottom of the frame beam, and the second-row side main reinforcement bars 26 at the top of the frame beam in the frame beam pass through the core area and form an integral body with the reinforced concrete ring beam, enhancing the ability of the core area to resist damage. The other main reinforcement bars 23 at the bottom, the other main reinforcement bars 27 at the top, and the waist reinforcement bars 28 are separately anchored into the reinforced concrete ring beam on the same side, avoiding the situation of crisscrossing of steel bars in the core area of the joint, providing necessary operating space for the binding and installation of steel bars, ensuring the binding quality of the steel bars in the core area of the beam-column joint, and effectively solving the common quality problem that it is difficult to ensure the construction quality of the reinforced concrete frame joint area.

[0088] In a specific embodiment, as Figures 14 - 18 shown, the height of the reinforced concrete ring beam 1 ≥ the height of the frame beam 2 + 50mm; the width of the reinforced concrete ring beam 1 ≥ the width of the frame beam 2, and it should be able to meet the anchorage requirements of the main reinforcement bars of the frame beam 2. The anchorage of the main reinforcement bars of the frame beam 2 in the reinforced concrete ring beam 1 shall be carried out in accordance with the provisions of GB50010.

[0089] The reinforced concrete ring beam 1 is provided with closed welded main reinforcement bars 11, 12, 13 at the upper part, and the area is not less than 0.7 times that of the upper main reinforcement bars of the frame beam. Closed welded main reinforcement bars 17-19 are provided at the lower part, and the area is not less than 0.7 times that of the lower main reinforcement bars of the frame beam. The lengths of the main reinforcement bars 13 and 19 = (bc + hc + 50) * 2, where bc and hc are the short side and long side dimensions of the frame column respectively, as Figures 14 - 15As shown; the spacing between the main bars 11 (17), 12 (18) and 13 (19) is ≤ 200 mm; the diameter of the stirrups 14 is ≥ A8 mm, the spacing is ≤ 100 mm, the diameter of the waist bars 15 is ≥ B14, the spacing between adjacent waist bars 15 is ≤ 200 mm, and the spacing between the tension bars 16 is ≤ 200 mm, see Figure 16 .

[0090] (3) The cross-sectional dimensions and reinforcement of frame beam 2 shall comply with the provisions of relevant specifications and the requirements of design documents. The position of the main reinforcement of the frame beam in the core plane is shown in Figure 4 The vertical relative position of the steel plate sleeve in the core area and the main reinforcement of the frame beam is shown in Figure 5 , the cross-sectional reinforcement diagram of reinforced concrete frame beam 2 is shown in Figure 6 , where b is the cross-sectional width of the frame beam and hb is the cross-sectional height.

[0091] The frame beam is provided with stirrup reinforcement zone at both ends, starting from the edge of the ring beam. The length of the stirrup reinforcement zone is S. When the seismic resistance level is level one, the length of the stirrup reinforcement zone at the beam end is S≥2.0hb and not less than 500mm; when the seismic resistance level is level two to four, the length of the stirrup reinforcement zone at the beam end is S≥1.5hb and not less than 500mm, where hb is the height of the frame beam.

[0092] The bottom angle bars 21 of the reinforced concrete frame beam 2 and the second row of beam side main bars 22 at the bottom of the beam pass through the core area 3 of the reinforced concrete beam-column node from under the steel plate sleeve; the other main bars 23 at the bottom are bent and anchored after completely passing through the ring beam on the same side, and the total anchorage length is ≥ l aE, where the anchorage length of the horizontal section is ≥ 0.4 l abE; The angle bars 25 of the reinforced concrete frame beam 2 and the second row of main bars 26 on the beam surface pass through the core area 3 of the reinforced concrete beam-column node from above the steel plate sleeve, and the other main bars 27 on the beam surface are bent and anchored after completely passing through the ring beam on the same side, and the total anchorage length ≥ l aE, horizontal section anchorage length ≥ 0.4 l abE; l aE is the anchorage length of the tensile reinforcement during earthquake resistance. l abE is the basic anchorage length of the tensile reinforcement of the main reinforcement; see Figure 5 shown.

[0093] For edge nodes with only one-side frame beams, the bottom angle bars 21 of the reinforced concrete frame beam 2 and the second row of beam side main bars 22 at the bottom of the beam pass through the core area 3 of the reinforced concrete beam-column node and extend to the edge of the ring beam on the other side for anchoring. The total anchorage length is ≥ l aE, horizontal section anchorage length ≥ 0.4 l abE; Figure 19 and Figure 20As shown in the figure, if the anchorage length is insufficient, anchor bars with a length three times the diameter of the main reinforcement can be fillet-welded on both sides of the end of the main reinforcement; the corner bars 25 on the beam surface and the second row of side main reinforcements 26 on the beam surface of the reinforced concrete frame beam 2 cross over the core area 3 of the reinforced concrete beam-column joint from the steel plate sleeve, completely pass through the ring beam on the other side and then bend for anchorage, and the total anchorage length ≥ l aE, and the anchorage length of the horizontal section ≥ 0.4 l abE; where l aE is the anchorage length of the tension reinforcement during seismic design, l abE is the basic anchorage length of the tension reinforcement of the main reinforcement.

[0094] When the heights of the frame beams on both sides of the core area are different, the schematic diagram of the anchorage structure of the main reinforcement of the frame beam in the node core area is shown in Figure 21 and Figure 22 ; if HE / Bhu ≤ 1 / 6, the bottom corner bars 21 and the second row of side main reinforcements 22 at the bottom of the higher beam pass through the core area and then bend upward to be lapped with the main reinforcement at the bottom on the other side; if HE / Bhu > 1 / 6, the bottom corner bars 21 and the second row of side main reinforcements 22 at the bottom of the higher beam pass through the core area and the ring beam on the other side and then bend for anchorage in the ring beam, and the total anchorage length ≥ l aE, and the anchorage length of the horizontal section ≥ 0.4 l abE; the bottom corner bars 21 and the second row of side main reinforcements 22 at the bottom of the lower beam extend to the edge of the steel plate sleeve and are anchored in the ring beam on the same side, and the total anchorage length ≥ l aE, and the anchorage length of the horizontal section ≥ 0.4 l abE; where l aE is the anchorage length of the tension reinforcement during seismic design, l abE is the basic anchorage length of the tension reinforcement of the main reinforcement; HE is the elevation difference between the main reinforcements on both sides, and Bhu is the width of the ring beam.

[0095] (4) Related components

[0096] ① To facilitate the insertion and extraction of the vibrating rod, measures such as increasing the diameter of the stirrups and appropriately reducing the stirrup spacing are taken in the frame column. On the premise that the stirrup limb distance meets the requirements of the Code for Seismic Design of Buildings GB50011, the stirrups 41 are installed avoiding the middle part with a diameter of about 200 mm in the core area, and the stirrups of the column section can adopt the form such as Figures 24 - 26 shown.

[0097] If, after taking the above measures, the frame columns still cannot meet the shear bearing capacity requirements, a steel plate sleeve 42 welded by steel strips can also be adopted inside the frame columns to replace some stirrups. At this time, the steel plate sleeve 42 inside the frame columns is also welded by four steel plates. Among them, t3 and t4 are the thicknesses of the steel strips on two opposite sides respectively. The strength and thickness of the steel plates and the calculation of the shear bearing capacity of the frame columns shall be carried out in accordance with the provisions of the current national standards such as "Loads on Building Structures" GB50009, "Code for Design of Concrete Structures" GB50010, "Standard for Design of Steel Structures" GB50017, "Technical Code for Concrete-Filled Steel Tubular Structures" GB50936, "Technical Specification for Concrete Structures of Tall Buildings" JGJ3, "Technical Specification for Steel Structures of High-Rise Civil Buildings" JGJ99 and the standard of China Engineering Construction Association "Technical Specification for Concrete-Filled Rectangular Steel Tubular Joints", etc.; for frame structures with seismic design, it shall also comply with the provisions of the current national standard "Code for Seismic Design of Buildings" GB50011; when calculating the flexural bearing capacity of the frame columns, the contribution of the steel plate sleeve shall be ignored and carried out in accordance with the current relevant provisions.

[0098] The steel plate sleeve 42 at the lower end H of the bottom column n within the range of 1 / 3 adopts full penetration welds. The steel plate sleeve 42 adopts full penetration welds within the range of Sc at the upper end of the bottom column. As Figure 27 shown, partial penetration welds can be adopted in the middle part, as Figure 28 shown; the height of the steel plate sleeve 42 of the bottom column = the distance from the bottom of the second-floor frame beam to the top surface of the foundation - 10mm;

[0099] The steel plate sleeve 42 adopts full penetration welds within the range of Sc at both ends of other floors, while partial penetration welds can be adopted in the middle part, where Sc≥h c Sc≥H n / 6, and Sc≥500mm, h c is the long side dimension of the cross-section of the frame column, and H n is the clear height of the frame column; the height of the steel plate sleeve 42 = the distance from the bottom of the upper-layer frame beam to the floor surface of the lower layer - 10mm.

[0100] At the column ends where the steel plate sleeve 42 adopts full penetration welds, stirrup dense areas are set, and the stirrup spacing ≤ 100mm. In other column segments, the stirrup spacing ≤ 200mm, see Figure 23 .

[0101] ② Foundation, the foundation 5 is constructed according to the actual design drawings.

[0102] The described construction method for the beam-column joints of the new reinforced concrete structure:

[0103] 1) Process and fabricate steel strips according to the requirements of the design drawings, and weld them into steel plate sleeves according to the design requirements.

[0104] 2) Fabricate the circular main reinforcement bars, frame beam reinforcement bars, waist reinforcement bars, frame column reinforcement bars, stirrups, etc.

[0105] 3) Construction process flow of the beam-column joints of the new reinforced concrete structure:

[0106] Floor axis positioning → Draw the column side lines on the floor → Weld or bind the main reinforcement bars 31 of the frame column or the main reinforcement bars 311 of the lower column → Draw the stirrup spacing lines on the main reinforcement bars of the column → Bind the stirrups 41 of the frame column 4 → Slip on the steel plate sleeve 42 of the column → Bind the reinforcement stirrups 331 in the core area 3 of the beam-column joint → Install the supports, and the bottom formworks of the frame column, slab, frame beam and ring beam → Slip on the stirrups 24 of the frame beam → Thread the bottom reinforcement bars of the frame beam 2 → Slip on the steel plate sleeve 32 on the main reinforcement bars 31 of the frame column 4 or the main reinforcement bars 312 of the upper column → Install the main reinforcement bars, waist reinforcement bars and stirrups of the ring beam → Thread the upper reinforcement bars of the frame beam 2 → Install the stirrups 33 in the core area → Slip on the steel plate sleeve 32 in the core area → Install the reinforcement stirrups 322 in the core area → Bind the stirrups of the frame beam 2 → Install the lateral formworks of the frame beam and the ring beam → Pour the concrete of the frame column 4 and the core area 3 of the beam-column joint by using a chute → Pour the concrete of the frame beam slab and the ring beam.

[0107] The present invention is applicable to the beam-column joints in the cast-in-place reinforced concrete frame structure system and the cast-in-place reinforced concrete frame-shear wall structure system.

[0108] Although the specific embodiments of the present invention have been described above, those skilled in the art of this technology should understand that the specific embodiments we described are illustrative rather than used to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should all be covered by the scope protected by the claims of the present invention.

Claims

1. A new type of beam-column joint of reinforced concrete structure, characterized in that: including the beam-column joint core area at the intersection of the frame beam and the frame column; the beam-column joint core area includes the main reinforcement bars passing through the beam-column joint core area in the frame column, as well as the stirrups, additional stirrups, steel plate sleeve, and concrete in the core area. The stirrups are tied outside the main reinforcement bars, the steel plate sleeve is sleeved outside the stirrups, and the steel plate sleeve also supports on the main reinforcement bars at the bottom of the frame beam passing through the core area; a reinforced concrete ring beam that surrounds the beam-column joint core area.

2. A new type of beam-column joint of reinforced concrete structure according to claim 1, characterized in that: The concrete strength of the reinforced concrete ring beam is the same as that of the beam slab. The height of the ring beam ≥ the height of the frame beam + 50mm; the width of the reinforced concrete ring beam ≥ the width of the frame beam and should meet the anchorage requirements of the main reinforcement bars of the frame beam. The anchorage of the main reinforcement bars of the frame beam in the ring beam shall be carried out in accordance with the provisions of GB50010.

3. A novel reinforced concrete beam-column joint according to claim 2, characterized in that: The diameter of the main reinforcement bars of the reinforced concrete ring beam ≥ B16, and the spacing ≤ 200mm; the diameter of the stirrups ≥ A8 is adopted, and the spacing ≤ 100mm; when the web height of the ring beam ≥ 450mm, waist reinforcement bars are arranged along the height on both sides of the ring beam, with a diameter ≥ B14, and the spacing of each side of the waist reinforcement bars ≤ 200mm, and the spacing of the tie bars between the waist reinforcement bars ≤ 200mm; the main reinforcement bars and the waist reinforcement bars are all connected by welding.

4. A novel reinforced concrete structural beam-column joint according to claim 1, characterized in that: The steel plate sleeve is welded by four steel plates, and full penetration welds are used for welding within the full height of the steel plate sleeve; the height of the steel plate sleeve = the clear distance between the bottom reinforcement bars of the frame beam passing through the core area and the top reinforcement bars of the beam passing through the core area - 10mm.

5. The novel reinforced concrete beam-column joint according to claim 1, characterized in that: The corner reinforcement bars in the frame beam and the beam side reinforcement bars in the second row pass through the core area and form an integral body with the reinforced concrete ring beam to enhance the ability of the core area to resist damage; while the non-beam side reinforcement bars in the 1st - 2nd rows and the reinforcement bars in the third row and above in the frame beam completely pass through the reinforced concrete ring beam on the same side and then are bent for anchorage; for the edge frame joints, the beam side reinforcement bars in the 1st - 2nd rows in the frame beam pass through the beam-column joint core area of the reinforced concrete beam and column and are anchored in the ring beam on the other side.

6. The novel reinforced concrete structural beam-column joint according to claim 1, wherein: When the cross-sectional dimensions of the upper and lower columns are different, the main reinforcement bars of the lower column extend to the top of the steel plate sleeve and then are bent for anchorage in the ring beam on the same side, and the total anchorage length ≥ 1.2laE, and the horizontal anchorage length ≥ 12d; the main reinforcement bars of the upper column extend to the bottom of the steel plate sleeve and then are bent for anchorage in the ring beam on the same side, and the total anchorage length ≥ 1.2laE, and the horizontal anchorage length ≥ 12d, where d is the diameter of the main reinforcement bar and laE is the anchorage length of the tension reinforcement bar during seismic design.

7. The novel reinforced concrete structural beam-column joint according to claim 1, characterized in that: At the top floor joint, the main reinforcement bars of the lower column extend to the top of the steel plate sleeve and then are bent for anchorage in the ring beam on the same side, and the total anchorage length ≥ 1.2laE, and the horizontal anchorage length ≥ 12d.

8. A novel reinforced concrete structural beam-column joint according to claim 1, characterized in that: Reinforced stirrups with a diameter ≥ B12mm are welded at the beam surface and bottom positions of the frame beam in the beam-column joint core area.

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