Long rectangular column and beam eccentric connection of beam column reinforced joint and its design method

Abstract

The application provides a long rectangular column and beam eccentric connection beam column reinforced joint and a design method, the reinforced joint comprising a steel beam, a steel pipe concrete column and a reinforced joint structure between the beam and the column. The reinforced joint structure between the beam and the column comprises a joint core area and a non-joint core area, horizontal cross partitions are arranged in the steel pipes of the joint core area and the non-joint core area and are filled with concrete, vertical partition plates and horizontal steel bars are additionally arranged in the steel pipe of the joint core area, and the wall of the steel pipe column on the side close to the eccentricity of the joint core area is partially thickened. The application is innovated based on the basic principles of the stress mechanism, the shear bearing capacity calculation formula and the joint core area width value of the long rectangular steel pipe concrete column and the steel beam eccentric connection beam column joint. After the beam column reinforced joint is used, the shear bearing capacity and the seismic ductility performance of the joint core area are greatly improved. The shear bearing capacity formula of the beam column joint in the current design specification standard is only applicable to the square steel pipe concrete column and the beam column without eccentricity, and the beam column reinforced joint and the shear bearing capacity calculation method provided by the application can be applied to the long rectangular steel pipe concrete column and the beam column eccentricity, thereby filling the blank of the current design specification standard.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building structures, in particular to a long rectangular column and beam eccentric connection beam column reinforced node and its design method BACKGROUND

[0002] When the plane size of super high-rise building is large, the cross section of long rectangular steel pipe concrete column is often used to improve the structural stiffness in the short direction, so that the structural stiffness in the two main directions tends to be consistent. At the same time, in order to meet the functional requirements of the building and ensure the indoor decoration effect as much as possible, the peripheral beam needs to be flush with the outer edge of the column or as close as possible to the edge, resulting in eccentricity between the beam and the column.

[0003] Under the action of horizontal loads such as earthquake and wind load, the eccentricity between the beam and the column causes additional torque and additional bending moment in the core area of the node, resulting in a decrease in the effective width of the core area of the node, a decrease in the shear bearing capacity of the node, and a great difference in the mechanical properties of the node area from the conventional beam column node. The influence of the eccentricity on the bearing capacity of the node cannot be ignored.

[0004] The calculation formula of the bearing capacity of the node domain in Technical Specification for Concrete-Filled Rectangular Steel Tubular Structures (CECS159:2004) is based on the research of Lü Xilin in 2000. The formula assumes that the sum of the shear bearing capacity of the steel pipe web, the weld, the inner diaphragm and the concrete in the node domain is the shear bearing capacity of the node domain. This formula is questionable about the assumption of the yield of the inner diaphragm, because the deformation of the inner diaphragm is constrained by the height of the nearby concrete and steel pipe, and it is not likely to yield. The formula also calculates the shear bearing capacity of the weld, which is not consistent with the actual situation. The formula does not consider the influence of axial pressure on the stress of concrete and steel pipe, which will overestimate the bearing capacity of the node domain. Lü Xilin also pointed out in a paper published in 2014 that the predicted value of CECS159 is much higher than the test value, and the shear bearing capacity of the node is reduced to 50% without considering the shear bearing capacity of the weld, and the contribution of the weld is not consistent with the actual situation.

[0005] CECS159 directly extends the theory and experimental research results of square steel pipe concrete column to rectangular section, which is not consistent with the long rectangular section in actual engineering. The beam width of the node test in the literature is equivalent to the column width, while in actual engineering, the column width of the steel pipe concrete column is often much larger than the beam width, and the beam column eccentricity is large. At this time, it is unreasonable to calculate the shear bearing capacity of the node core area according to the full section of the steel pipe concrete column.

[0006] Based on the above problems, the application provides a long rectangular column and beam eccentric connection beam column reinforced joint and a design method from the basic principles of the stress mechanism, the shear capacity calculation formula and the node core area width value of the long rectangular steel pipe concrete column and the steel beam eccentric connection beam column joint. After the beam column reinforced joint provided by the application is used, the shear capacity and seismic ductility performance of the node core area are greatly improved, the problem of insufficient shear capacity of the node under large stress is effectively solved, and the structure design can directly use the calculation formula provided by the application to check the shear capacity. SUMMARY

[0007] The application aims to provide a long rectangular column and beam eccentric connection beam column reinforced joint, solve the problem of insufficient shear capacity of the node core area due to the decrease of the effective shear section of the node core area caused by large stress and beam column eccentricity of the beam column joint, and provide a shear capacity calculation formula and a node core area width value method of the reinforced joint structure for the long rectangular steel pipe concrete column and the beam column eccentricity, and fill the blank of the current design specification standard.

[0008] To achieve the above-mentioned purpose, the application provides a long rectangular column and beam eccentric connection beam column reinforced joint, which comprises a steel beam, a long rectangular steel pipe concrete column and a reinforced joint structure between the beam column, the steel beam and the steel pipe concrete column are eccentrically connected, wherein the reinforced joint structure between the beam column comprises a node core area and a non-node core area, a horizontal diaphragm is arranged in the steel pipe of the node core area and the non-node core area and is filled with concrete, a vertical partition plate and a horizontal steel bar are additionally arranged in the steel pipe of the node core area, and the steel pipe column wall on the side close to the eccentricity of the node core area in the checking direction is locally thickened;

[0009] The checking direction is the short side direction of the long rectangular steel pipe concrete column, the thickness of the vertical partition plate additionally arranged in the steel pipe of the node core area is t w1 The thickness of the steel pipe column wall on the side close to the eccentricity of the node core area in the checking direction is t w2 The sum of the sectional areas of all the steel bars additionally arranged in the steel pipe of the node core area in the same section is A svj The following formulas (1), (2), (3), (4) and (5) are used for calculation:

[0010] (1)

[0011] (2)

[0012] (3)

[0013] (4)

[0014] (5)

[0015] wherein: V ｊ is the shear design value of the reinforced beam-column joint; V ｊu is the shear capacity of the reinforced beam-column joint; h c is the sectional height of the steel pipe column in the checking direction; b c is the sectional width of the steel pipe column perpendicular to the checking direction; b j is the width of the joint core zone; h b is the height of the steel beam in the checking direction; t w is the average thickness of the vertical partition plate added in the steel pipe in the joint core zone and the steel pipe column wall close to the eccentric side in the checking direction, i.e. t w = t w1 + t w2 ) / 2, t w1 is the thickness of the vertical partition plate added in the steel pipe in the joint core zone; t w2 is the thickness of the steel pipe column wall close to the eccentric side in the checking direction in the joint core zone; t f is the thickness of the steel pipe column wall perpendicular to the checking direction; t i is the thickness of the horizontal partition plate in the steel pipe column in the joint core zone; t bf is the thickness of the steel beam flange; f c is the design value of the compressive strength of the concrete in the joint core zone; f yv is the tensile strength of the horizontal steel reinforcement added in the steel pipe in the joint core zone; f a is the average value of the design value of the tensile strength of the vertical partition plate added in the steel pipe in the joint core zone and the steel pipe column wall close to the eccentric side in the checking direction; f af is the design value of the tensile strength of the steel pipe column wall perpendicular to the checking direction; A svj is the sum of sectional areas of each steel reinforcement in the same section of the horizontal steel reinforcement added in the steel pipe in the joint core zone, i.e. A svj = nA svj1 , nThis refers to the number of horizontal reinforcing bars within the same cross-section. A svj1 This represents the cross-sectional area of ​​a single horizontal reinforcing bar. s Vertical spacing of horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node; η c The coefficient for increasing the compressive strength of the confined concrete in the core area of ​​the node; b Let b be the longer side of the rectangular cross-section of the node core region, and b = max( h c , b j ); t for b The thickness of the steel plate corresponding to the edge; f yk This represents the standard value of the yield strength of the steel pipe column wall. f ck σ is the standard value of the compressive strength of the concrete in the core area of ​​the node; s The stress in the wall of the steel pipe column; N The axial pressure at the bottom of the column at the node; E s The elastic modulus of the steel pipe column; A s The cross-sectional area of ​​the steel pipe column; E c The elastic modulus of the concrete in the core area of ​​the node; A c This represents the cross-sectional area of ​​the concrete in the core region of the node. M dcf The yield moment of the diaphragm-steel tube flange frame; γ RE The bearing capacity seismic adjustment coefficient is 0.8 for seismic conditions and 1.0 for non-seismic conditions.

[0016] Furthermore, the width of the core area of ​​the beam-column reinforced joint structure. b j The possible values ​​are as follows:

[0017] When the edge of the steel beam is flush with the edge of the steel pipe column: b j = b b +0.2 h c

[0018] When the edge of the steel beam is not flush with the edge of the steel pipe column: b j = b b +0.2 h c + X

[0019] wherein: h c is the section height of the steel pipe column in the checking direction; b b is the width of the steel beam in the checking direction; X is the distance from the outer edge of the steel beam on the eccentric side of the joint to the edge of the steel pipe column on the eccentric side of the joint, when X > 0.20 h c = 0.20 X h c

[0020] The non-joint core area width of the beam-column reinforced joint structure is the section width of the steel pipe column perpendicular to the checking direction minus the joint core area width, i.e. b c b j

[0021] Further, the horizontal reinforcement additionally arranged in the joint core area steel pipe is parallel to the steel pipe column wall in the checking direction, and the two ends are connected to the inner side of the steel pipe column wall perpendicular to the checking direction by T-shaped welding; the horizontal and vertical spacing of the horizontal reinforcement additionally arranged in the joint core area steel pipe is controlled to be 100mm-150mm.

[0022] Further, the vertical partition plate additionally arranged in the joint core area steel pipe is parallel to the steel pipe column wall in the checking direction, and the plane position is located at the joint between the joint core area and the non-joint core area.

[0023] Further, the left and right sides of the vertical partition plate additionally arranged in the joint core area steel pipe are connected to the inner side of the steel pipe column wall perpendicular to the checking direction by full penetration welding; the upper end of the vertical partition plate additionally arranged in the joint core area steel pipe extends 500mm to the upper surface of the upper horizontal partition plate arranged in the steel pipe, and the lower end extends 500mm to the lower surface of the lower horizontal partition plate arranged in the steel pipe.

[0024] Further, the steel pipe column wall on the eccentric side of the joint core area in the checking direction is locally thickened, and the thickened height is 500mm above the upper surface of the upper horizontal partition plate arranged in the steel pipe at the upper end, and 500mm below the lower surface of the upper horizontal partition plate arranged in the steel pipe at the lower end.

[0025] ​​​​Further, the horizontal diaphragm plates arranged in the steel pipes of the node core area and the non-node core area include upper horizontal diaphragm plates and lower horizontal diaphragm plates, the upper horizontal diaphragm plates are aligned with the upper flanges of the steel beams, and the lower horizontal diaphragm plates are aligned with the lower flanges of the steel beams; the plate thickness of the horizontal diaphragm plates is the same as the flange plate thickness of the steel beams; the horizontal diaphragm plates are respectively provided with grouting holes with a diameter of 200mm-250mm in the middle of the node core area and the non-node core area.

[0026] Further, the wall thickness of the steel pipe concrete column of the non-reinforced node structure area and the internal grouting concrete strength grade are determined according to the axial force, bending moment and shear force borne by the steel pipe concrete column; the wall thickness of the steel pipe concrete column meets the construction requirements of the specification.

[0027] Further, the reinforced node is provided with three independent reinforcing measures, i.e., a vertical partition plate is additionally arranged in the steel pipe of the node core area, the wall of the steel pipe column near the eccentric side in the calculation direction of the node core area is locally thickened, and horizontal steel bars are additionally arranged in the steel pipe of the node core area; one, two or three measures can be selected according to the beam column eccentricity and the stress state of the node to reinforce.

[0028] The application effectively solves the problem that the effective shear section of the beam column node is reduced due to large stress and beam column eccentricity, and the shear bearing capacity of the node is insufficient; meanwhile, the beam column reinforced node of the application is suitable for long rectangular cross-section steel pipe concrete columns, and is not limited to the square cross-section or the rectangular cross-section close to the square required in the shear bearing capacity formula of the specification node. The shear bearing capacity calculation formula and the node core area width value method of the reinforced node structure provided by the application are used for long rectangular steel pipe concrete columns and beam column eccentricity, and fill the gap of the current design specification standard.

[0029] The application further provides a design method of the long rectangular column and beam eccentric connection beam column reinforced node, which comprises the following steps:

[0030] 1) horizontal diaphragm plates are arranged in the steel pipes of the node core area and the non-node core area and grouted with concrete, meanwhile, vertical partition plates and horizontal steel bars are additionally arranged in the steel pipe of the node core area, and the wall of the steel pipe column near the eccentric side in the calculation direction of the node core area is locally thickened;

[0031] 2) the thickness of the vertical partition plate additionally arranged in the steel pipe of the node core area t w1 , the thickness of the wall of the steel pipe column near the eccentric side in the calculation direction of the node core area t w2 and the sum of the sectional areas of the horizontal steel bars additionally arranged in the steel pipe of the node core area A svjThe following formulas (1), (2), (3), (4), (5) are used for calculation:

[0032] (1)

[0033] (2)

[0034] (3)

[0035] (4)

[0036] (5)

[0037] In the formula: V ｊ is the shear design value of the reinforced beam-column joint; V ｊu is the shear capacity of the reinforced beam-column joint; h c is the sectional height of the steel pipe column in the checking direction; b c is the sectional width of the steel pipe column perpendicular to the checking direction; b j is the width of the joint core area; h b is the height of the steel beam in the checking direction; t w1 is the vertical partition thickness added in the steel pipe in the joint core area; t w is the average thickness of the vertical partition plate added in the steel pipe in the joint core area and the wall of the steel pipe column close to the eccentric side in the checking direction, i.e. t w ( t w1 + t w2 ) / 2, t w1 is the thickness of the vertical partition plate added in the steel pipe in the joint core area; t w2 is the wall thickness of the steel pipe column close to the eccentric side in the checking direction in the joint core area; t f is the wall thickness of the steel pipe column perpendicular to the checking direction; t i is the thickness of the horizontal partition plate in the steel pipe column in the joint core area; t bf is the flange thickness of the steel beam; f c is the design value of the compressive strength of the concrete in the joint core area; f yvThe tensile strength of the horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node; f a The average of the design values ​​of the tensile strength of the vertical partition plate added inside the steel pipe in the core area of ​​the node and the steel pipe column wall on the side closer to the eccentricity in the verification direction; f af The design value of the tensile strength of the steel pipe column wall perpendicular to the verification direction; A svj The sum of the cross-sectional areas of all horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node, i.e. A svj = nA svj1 , n This refers to the number of horizontal reinforcing bars within the same cross-section. A svj1 This represents the cross-sectional area of ​​a single horizontal reinforcing bar. s Vertical spacing of horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node; η c The coefficient for increasing the compressive strength of the confined concrete in the core area of ​​the node; b Let the long side of the rectangular cross-section of the node's core area be the long side. b =max( h c , b j ); t for b The thickness of the steel plate corresponding to the edge; f yk This represents the standard value of the yield strength of the steel pipe column wall. f ck σ is the standard value of the compressive strength of the concrete in the core area of ​​the node; s The stress in the wall of the steel pipe column; N The axial pressure at the bottom of the column at the node; E s The elastic modulus of the steel pipe column; A s The cross-sectional area of ​​the steel pipe column; E c The elastic modulus of the concrete in the core area of ​​the node; A c This represents the cross-sectional area of ​​the concrete in the core area of ​​the node. M dcf The yield moment of the diaphragm-steel tube flange frame; γ RE The bearing capacity seismic adjustment coefficient is 0.8 for seismic conditions and 1.0 for non-seismic conditions.

[0038] 3) Width of the core area of ​​the beam-column reinforced joint structure b jThe possible values ​​are as follows:

[0039] When the edge of the steel beam is flush with the edge of the steel pipe column: b j = b b +0.2 h c

[0040] When the edge of the steel beam is not flush with the edge of the steel pipe column: b j = b b +0.2 h c + X

[0041] In the formula: h c To verify the height of the steel pipe column section in the direction; b b To verify the width of the directional steel beam; X Let be the distance from the outer edge of the steel beam on the eccentric side of the node to the edge of the steel pipe column on the eccentric side of the node. X >0.20 h c At that time, take X =0.20 h c ;

[0042] The width of the non-node core area of ​​the beam-column reinforced joint structure is the width of the steel pipe column section perpendicular to the verification direction minus the width of the node core area, i.e. b c – b j ;

[0043] 4) The horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node are parallel to the steel pipe column wall in the verification direction, and their two ends are connected to the inner side of the steel pipe column wall perpendicular to the verification direction by T-shaped welding; the horizontal spacing and vertical spacing of the horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node are controlled at 100mm~150mm.

[0044] 5) The vertical partition plate added inside the steel pipe in the core area of ​​the node is parallel to the steel pipe column wall in the verification direction, and its planar position is located at the junction of the core area of ​​the node and the non-core area of ​​the node.

[0045] 6) The vertical partition plate added inside the steel pipe in the core area of ​​the node is connected to the inner side of the steel pipe column wall perpendicular to the calculation direction by full penetration welding on both the left and right sides; the upper end of the vertical partition plate added inside the steel pipe in the core area of ​​the node extends 500mm to the upper surface of the upper horizontal diaphragm plate set inside the steel pipe, and the lower end extends 500mm to the lower surface of the lower horizontal diaphragm plate set inside the steel pipe.

[0046] 7) The wall of the steel pipe column near the eccentric side in the checking direction of the node core area is locally thickened, the upper end of the thickened height is 500 mm above the upper surface of the upper horizontal diaphragm arranged in the steel pipe, and the lower end of the thickened height is 500 mm below the lower surface of the upper horizontal diaphragm arranged in the steel pipe;

[0047] 8) The horizontal diaphragms arranged in the steel pipe of the node core area and the non-node core area include upper horizontal diaphragms and lower horizontal diaphragms, the upper horizontal diaphragms are aligned with the upper flanges of the steel beam, and the lower horizontal diaphragms are aligned with the lower flanges of the steel beam; the plate thickness of the horizontal diaphragm is the same as the flange plate thickness of the steel beam; the horizontal diaphragm is provided with a grouting hole with a diameter of 200 mm to 250 mm in the middle of the node core area and the non-node core area;

[0048] 9) The wall thickness and the concrete strength grade of the steel pipe concrete column in the non-strengthened node structure area are determined according to the axial force, bending moment and shear force borne by the steel pipe concrete column; the wall thickness of the steel pipe column on the remaining three sides of the strengthened node structure area in the node core area and the non-node core area is the same as that of the steel pipe concrete column in the non-strengthened node structure area, except for the wall of the steel pipe column near the eccentric side in the checking direction of the node core area; the wall thickness of the steel pipe concrete column in the strengthened node structure area and the non-strengthened node structure area meets the construction requirements of the specification; BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is a plan view of the beam-column strengthened node of the application;

[0050] Figure 2 It is a plan view of the beam-column strengthened node of the application; Figure 1 It is an A-A sectional view of the beam-column strengthened node of the application;

[0051] Figure 3 It is a B-B sectional view of the beam-column strengthened node of the application; Figure 1 It is a B-B sectional view of the beam-column strengthened node of the application;

[0052] In the figure, d is the node core area, p is the non-node core area, 1 is a vertical partition plate additionally arranged in the steel pipe in the node core area, 2 is a horizontal steel bar additionally arranged in the steel pipe in the node core area, 3 is the wall of the steel pipe column near the eccentric side in the checking direction of the node core area, 4 is the wall of the steel pipe column far from the eccentric side in the checking direction, 5 is the wall of the steel pipe column perpendicular to the checking direction, 6 is a horizontal diaphragm arranged in the steel pipe in the node core area and the non-node core area, 61 is an upper horizontal diaphragm arranged in the steel pipe in the node core area and the non-node core area, 62 is a lower horizontal diaphragm arranged in the steel pipe in the node core area and the non-node core area, 7 is a steel pipe concrete column, 8 is a steel beam, 81 is the upper flange of the steel beam, and 82 is the lower flange of the steel beam, h c It is the sectional height of the steel pipe column in the checking direction; b cwidth of the steel pipe column section perpendicular to the checking direction; b b width of the steel beam in the checking direction; h b height of the steel beam in the checking direction; b j width of the node core area; X distance between the outer edge of the steel beam on the eccentric side of the node and the edge of the steel pipe column on the eccentric side of the node. DETAILED DESCRIPTION

[0053] The application will be further described below with reference to the accompanying drawings.

[0054] Referring to Figure 1 , Figure 2 and Figure 3 , a beam-column reinforced node of eccentric connection between a long rectangular column and a beam includes a steel beam, a steel pipe concrete column and a reinforced node structure between the beam and the column. The reinforced node structure between the beam and the column includes a node core area d and a non-node core area p, a horizontal diaphragm 6 is arranged in the steel pipe of the node core area d and the non-node core area p and is filled with concrete, a vertical partition plate 1 and a horizontal steel bar 2 are additionally arranged in the steel pipe of the node core area d, and the wall 3 of the steel pipe column on the side close to the eccentric side of the node core area in the checking direction is locally thickened.

[0055] thickness of the vertical partition plate 1 additionally arranged in the steel pipe of the node core area d t w1 thickness of the wall 3 of the steel pipe column on the side close to the eccentric side of the node core area d in the checking direction t w2 total of sectional areas of the horizontal steel bars 2 additionally arranged in the steel pipe of the node core area d in the same section A svj are calculated according to the following formulas (1), (2), (3), (4) and (5):

[0056] (1)

[0057] (2)

[0058] (3)

[0059] (4)

[0060] (5)

[0061] In the formulas, V is the shear design value of the beam-column reinforced node; V ｊ V is the shear design value of the beam-column reinforced node; V ｊu V is the shear design value of the beam-column reinforced node;h c is the cross-sectional height of the steel pipe column in the checking direction; b c is the cross-sectional width of the steel pipe column perpendicular to the checking direction; b j is the width of the core zone of the joint; h b is the height of the steel beam in the checking direction; t w is the average thickness of the vertical partition plate added in the steel pipe in the core zone of the joint and the steel pipe column wall close to the eccentric side in the checking direction, i.e. t w = t w1 + t w2 ) / 2, t w1 is the thickness of the vertical partition plate added in the steel pipe in the core zone of the joint; t w2 is the thickness of the steel pipe column wall close to the eccentric side in the checking direction in the core zone of the joint; t f is the thickness of the steel pipe column wall perpendicular to the checking direction; t i is the thickness of the horizontal partition plate in the steel pipe column in the core zone of the joint; t bf is the flange thickness of the steel beam; f c is the design value of the compressive strength of the concrete in the core zone of the joint; f yv is the tensile strength of the horizontal steel reinforcement added in the steel pipe in the core zone of the joint; f a is the average value of the design value of the tensile strength of the vertical partition plate added in the steel pipe in the core zone of the joint and the steel pipe column wall close to the eccentric side in the checking direction; f af is the design value of the tensile strength of the steel pipe column wall perpendicular to the checking direction; A svj is the sum of the sectional areas of each steel reinforcement in the same cross section of the horizontal steel reinforcement added in the steel pipe in the core zone of the joint, i.e. A svj = nA svj1 , n is the number of horizontal steel reinforcements in the same cross section, A svj1 is the sectional area of a single horizontal steel reinforcement; s is the vertical spacing of the horizontal steel reinforcement added in the steel pipe in the core zone of the joint; η c is the compressive strength improvement coefficient of the confined concrete in the core zone of the joint;b Let b be the longer side of the rectangular cross-section of the node core region, and b = max( h c , b j ); t for b The thickness of the steel plate corresponding to the edge; f yk This represents the standard value of the yield strength of the steel pipe column wall. f ck σ is the standard value of the compressive strength of the concrete in the core area of ​​the node; s The stress in the wall of the steel pipe column; N The axial pressure at the bottom of the column at the node; E s The elastic modulus of the steel pipe column; A s The cross-sectional area of ​​the steel pipe column; E c The elastic modulus of the concrete in the core area of ​​the node; A c This represents the cross-sectional area of ​​the concrete in the core region of the node. M dcf The yield moment of the diaphragm-steel tube flange frame; γ RE The bearing capacity seismic adjustment coefficient is 0.8 for seismic conditions and 1.0 for non-seismic conditions.

[0062] The width of the node core area of ​​the beam-column reinforced joint structure b j The possible values ​​are as follows:

[0063] When the edge of steel beam 8 is flush with the edge of steel pipe column 7: b j = b b +0.2 h c

[0064] When the edge of steel beam 8 is not flush with the edge of steel pipe column 7: b j = b b +0.2 h c + X

[0065] In the formula: h c To verify the height of the steel pipe column section in the direction; b b To verify the width of the directional steel beam; X Let be the distance from the outer edge of the steel beam on the eccentric side of the node to the edge of the steel pipe column on the eccentric side of the node.X 0.20 h c when X =0.20 h c .

[0066] The non-node core area width of the beam-column reinforced node structure is the steel pipe column section width perpendicular to the calculation direction minus the node core area width, that is, b c - b j .

[0067] The horizontal steel bars 2 additionally arranged in the steel pipe of the node core area d are parallel to the steel pipe column wall in the calculation direction, and the two ends are connected to the inner side of the steel pipe column wall 5 perpendicular to the calculation direction by T-shaped welding; the horizontal and vertical spacing of the horizontal steel bars 2 additionally arranged in the steel pipe of the node core area d is controlled to be 100mm-150mm.

[0068] The vertical partition plate 1 additionally arranged in the steel pipe of the node core area d is parallel to the steel pipe column wall in the calculation direction, and the plane position is located at the junction of the node core area d and the non-node core area p.

[0069] The left and right sides of the vertical partition plate 1 additionally arranged in the steel pipe of the node core area d are connected to the inner side of the steel pipe column wall 5 perpendicular to the calculation direction by full penetration welding; the upper end of the vertical partition plate 1 additionally arranged in the steel pipe of the node core area d extends 500mm to the upper surface of the upper horizontal partition plate 61 arranged in the steel pipe, and the lower end extends 500mm to the lower surface of the lower horizontal partition plate 62 arranged in the steel pipe.

[0070] The steel pipe column wall 3 near the eccentric side of the node core area in the calculation direction is locally thickened, and the thickening height is 500mm above the upper surface of the upper horizontal partition plate 61 arranged in the steel pipe and 500mm below the lower surface of the lower horizontal partition plate 62 arranged in the steel pipe.

[0071] The horizontal partition plate 6 arranged in the steel pipe of the node core area d and the non-node core area p includes an upper horizontal partition plate 61 and a lower horizontal partition plate 62, the upper horizontal partition plate 61 is aligned with the upper flange 81 of the steel beam, and the lower horizontal partition plate 62 is aligned with the lower flange 82 of the steel beam; the thickness of the horizontal partition plate 6 is the same as the thickness of the flange plate of the steel beam 8; the horizontal partition plate 6 respectively reserves a grouting hole with a diameter of 200mm-250mm in the middle of the node core area d and the non-node core area p.

[0072] The wall thickness of the steel pipe concrete column of the non-reinforced node structure area and the strength grade of the inner filled concrete are determined according to the axial force, bending moment and shear force borne by the steel pipe concrete column; the steel pipe column walls of the reinforced node structure area on the three sides except the side of the node core area d close to the eccentric side in the checking direction are of the same wall thickness as the steel pipe concrete column wall of the non-reinforced node structure area; and the wall thicknesses of the steel pipe concrete column walls of the reinforced node structure area and the non-reinforced node structure area satisfy the construction requirements of the specification.

[0073] The reinforced node is provided with a vertical partition plate 1 in the steel pipe of the node core area d, the steel pipe column wall 3 on the side close to the eccentric side of the node core area in the checking direction is locally thickened, and a horizontal steel bar 2 is additionally arranged in the steel pipe of the node core area d; the three independent reinforcing measures can be selected according to the beam-column eccentricity and the stress state of the node to perform reinforcement.

[0074] In the application, the node core area d refers to the area where the beam and column members intersect, and is a cuboid area with a specific length in the height of the steel pipe column section in the checking direction h c , a specific width in the height of the column section in the checking direction b j , and a height equal to the height of the steel beam in the checking direction. H b The non-node core area p refers to the area in the cuboid within the height of the steel beam H b , except the node core area d.

[0075] In the application, the checking direction refers to the short side direction of the long rectangular steel pipe concrete column, i.e., the horizontal direction in the attached Figure 1 .

[0076] For example, the sectional size of the long rectangular steel pipe concrete column of a super high-rise office building is 500*1000*20, the sectional size of the steel beam is H800*300*14*25, the edge of the steel beam is flush with the edge of the steel pipe concrete column, the eccentricity is 350mm, the strength grade of the inner filled concrete of the steel pipe is C50, the material of the steel pipe column and the steel beam is Q355B, and the horizontal steel bar arranged in the node core area of the steel pipe is HRB400. b c =1000mm, h c =500mm, b b =300mm, t f =20mm, t i = t af =25mm,f c = 23.1 MPa, f yv = 360 MPa, f a = f af = 295 MPa, f yk = 355 MPa, f ck = 32.4 MPa, γ RE = 0.80, the design value of the axial force at the bottom of the column at the node N= 20000 kN, the design value of the shear force in the core area of the node V ｊ = 7050 kN.

[0077] The beam-column reinforced node and the design method provided by the application have the advantages that the width of the core area of the node is b j = b b + 0.2 h c + X = 300 + 0.2 x 500 + 0 = 400 mm, the thickness of the vertical partition plate additionally arranged in the steel pipe in the core area of the node t w1 = 30 mm, the local thickness of the wall of the steel pipe column near the eccentric side in the checking direction of the core area of the node is thickened to t w2 = 30 mm, and thus t w = 30 mm, the sum of the sectional areas of the horizontal steel bars in the same section and arranged in the steel pipe in the core area of the node A svj = 3 x 379.9 = 1139.7 mm 2 , the vertical spacing of the horizontal steel bars is 100 mm. According to formula (2), the compression strength improvement coefficient of the confined concrete in the core area of the node is η c = 1.287; according to formula (3), the stress σ of the wall of the steel pipe column is s = 151.1 MPa; and according to formula (1), the shear capacity of the beam-column reinforced node is V ｊu = 7500 kN, V ｊ = 7050 kN V ｊu = 7500 kN, which meets the requirement of formula (1); 0.2 V ｊ = 1410 kN fyv A svj ( h c -2 t f )] / γ RE =1887kN<0.4 V ｊ =2820kN, meet the formula (5) requirements. The beam-column joint of the project uses the beam-column reinforcing joint provided by the application, and the shear capacity and seismic ductility performance of the joint core area are greatly improved, solving the problem of insufficient shear capacity of the beam-column joint caused by large shear force and beam-column eccentricity.

Claims

1. A beam-column reinforcement joint for an eccentric connection between a long rectangular column and a beam, comprising a steel beam, a long rectangular steel-concrete composite column, and a reinforcement joint structure between the beam and the column, wherein the steel beam and the steel-concrete composite column are eccentrically connected, characterized in that: Strengthening the node structure includes the node core area and non-node core area. Horizontal diaphragms are installed and concrete is poured inside the steel pipes in the node core area and non-node core area. At the same time, vertical partition plates and horizontal steel bars are added inside the steel pipes in the node core area. The steel pipe column wall near the eccentric side of the node core area is locally thickened. The verification direction is the short side of the long rectangular steel-concrete composite column, and the thickness of the vertical partition plate added inside the steel pipe in the core area of ​​the node is also considered. t w1 The thickness of the steel pipe column wall near the eccentric side in the core area of ​​the node is verified. t w2 The sum of the cross-sectional areas of all horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node within the same cross-section. A svj Calculate using the following formulas (1), (2), (3), (4), and (5): (1) (2) (3) (4) (5) In the formula: V ｊ Design values ​​for shear force at beam-column joints; V ｊu Strengthen the shear bearing capacity of beam-column joints; h c To verify the height of the steel pipe column section in the direction; b c The width of the steel pipe column section is perpendicular to the verification direction; b j The width of the node's core area; h b To verify the height of the directional steel beam; t w The average thickness of the vertical partition plate added inside the steel pipe in the core area of ​​the node and the steel pipe column wall on the side closer to the eccentricity in the verification direction, i.e. t w =( t w1 + t w2 ) / 2, t w1 The thickness of the vertical partition plate added inside the steel pipe in the core area of ​​the node; t w2 The thickness of the steel pipe column wall is verified in the core area of ​​the node, with the direction closer to the eccentric side. t f The thickness of the steel pipe column wall is perpendicular to the verification direction; t i The thickness of the horizontal diaphragm inside the steel pipe column in the core area of ​​the node; t bf This refers to the flange thickness of the steel beam. f c This refers to the design value of the compressive strength of the concrete in the core area of ​​the node. f yv The tensile strength of the horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node; f a The average of the design values ​​of the tensile strength of the vertical partition plate added inside the steel pipe in the core area of ​​the node and the steel pipe column wall on the side closer to the eccentricity in the verification direction; f af The design value of the tensile strength of the steel pipe column wall perpendicular to the verification direction; A svj The sum of the cross-sectional areas of all horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node, i.e. A svj = nA svj1 , n This refers to the number of horizontal reinforcing bars within the same cross-section. A svj1 This represents the cross-sectional area of ​​a single horizontal reinforcing bar. s Vertical spacing of horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node; η c The coefficient for increasing the compressive strength of the confined concrete in the core area of ​​the node; b Let b be the longer side of the rectangular cross-section of the node core area, and b = max( h c , b j ); t for b The thickness of the steel plate corresponding to the edge; f yk This represents the standard value of the yield strength of the steel pipe column wall. f ck σ is the standard value of the compressive strength of the concrete in the core area of ​​the node; s The stress in the wall of the steel pipe column; N The axial pressure at the bottom of the column at the node; E s The elastic modulus of the steel pipe column; A s The cross-sectional area of ​​the steel pipe column; E c The elastic modulus of the concrete in the core area of ​​the node; A c This represents the cross-sectional area of ​​the concrete in the core area of ​​the node. M dcf The yield moment of the diaphragm-steel tube flange frame; γ RE The bearing capacity seismic adjustment coefficient is 0.8 for seismic conditions and 1.0 for non-seismic conditions.

2. The beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The width of the node core area of ​​the reinforced node structure b j The possible values ​​are as follows: When the edge of the steel beam is flush with the edge of the steel pipe column: b j = b b +0.2 h c When the edge of the steel beam is not flush with the edge of the steel pipe column: b j = b b +0.2 h c + X In the formula: h c To verify the height of the steel pipe column section in the direction; b b The width of the steel beam; X Let be the distance from the outer edge of the steel beam on the eccentric side of the node to the edge of the steel pipe column on the eccentric side of the node. X >0.20 h c At that time, take X =0.20 h c ; The width of the non-node core area of ​​the reinforced node structure is the width of the steel pipe column section perpendicular to the verification direction minus the width of the node core area, i.e. b c – b j .

3. The beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node are parallel to the steel pipe column wall in the verification direction, and their two ends are connected to the inner side of the steel pipe column wall perpendicular to the verification direction by T-shaped welding; the horizontal spacing and vertical spacing of the horizontal reinforcing bars added inside the steel pipe in the core area of ​​the node are 100mm~150mm.

4. A beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The vertical partition plate added inside the steel pipe in the core area of ​​the node is parallel to the steel pipe column wall in the verification direction, and its planar position is located at the junction of the core area of ​​the node and the non-core area.

5. A beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The vertical partition plates added inside the steel pipe in the core area of ​​the node are connected to the inner side of the steel pipe column wall perpendicular to the calculation direction by full penetration welding on both the left and right sides. The upper end extends 500mm to the upper surface of the upper horizontal partition plate set inside the steel pipe, and the lower end extends 500mm to the lower surface of the lower horizontal partition plate set inside the steel pipe.

6. A beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The steel pipe column wall near the eccentric side of the node core area is locally thickened. The upper end of the thickening height extends 500mm above the upper surface of the upper horizontal diaphragm installed inside the steel pipe, and the lower end of the thickening height extends 500mm below the lower surface of the upper horizontal diaphragm installed inside the steel pipe.

7. A beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The thickness of the horizontal diaphragm installed inside the steel pipe in the node core area and non-node core area is the same as the thickness of the flange plate of the steel beam. The horizontal diaphragm has grouting holes with a diameter of 200mm to 250mm reserved in the middle of the node core area and non-node core area respectively.

8. A beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 7, characterized in that: The horizontal diaphragm includes an upper horizontal diaphragm and a lower horizontal diaphragm. The upper horizontal diaphragm is aligned with the upper flange of the steel beam, and the lower horizontal diaphragm is aligned with the lower flange of the steel beam.

9. A beam-column reinforcement joint for eccentric connection of a long rectangular column and a beam according to claim 1, characterized in that: The wall thickness of the steel-concrete composite column and the strength grade of the internal concrete in the non-reinforced joint structural zone are determined based on the axial force, bending moment, and shear force borne by the steel-concrete composite column. In the reinforced joint structure, except for the steel-concrete composite column wall on the side closer to the eccentric side in the verification direction of the joint core zone, the steel-concrete composite column walls on the other three sides of the reinforced joint structural zone have the same wall thickness as the steel-concrete composite column in the non-reinforced joint structural zone. The wall thickness of the steel-concrete composite column in both the reinforced and non-reinforced joint structural zones meets the structural requirements of the code.

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