Transition joint structure of steel-concrete arch and steel-concrete beam and design method thereof

Abstract

This invention discloses a transition node structure and its design method for the intersection of a reinforced concrete arch and a reinforced concrete beam, relating to the field of building technology. The transition node structure includes a main support column, a reinforced concrete beam, a reinforced concrete arch, and a transition section. One end of the reinforced concrete beam passes horizontally through the main support column. The end of the reinforced concrete arch is fixedly connected to one end of the transition section. The other end of the transition section is fixedly connected to both the reinforced concrete beam and the main support column. The transition section includes a curved panel, a first triangular panel, a second triangular panel, and vertical ribs. The curved panel and the triangular panel are staggered, and the bottom edge of the curved panel is fixedly connected to the end of the reinforced concrete arch. The side edges of the triangular panels are fixedly connected to the side edges of the curved panel. The beneficial effects of this invention are: it can reconstruct the force transmission path between the reinforced concrete arch and the reinforced concrete beam to achieve distributed pressure and orderly transmission of tensile force; and it can achieve a smooth transition in the cross-sectional shape and stiffness of the reinforced concrete arch and the reinforced concrete beam to prevent abrupt changes in their cross-sectional shape and stiffness.

Description

Technical Field

[0001] This invention relates to the field of building technology, and more specifically, to a transition node structure and design method for the intersection of a steel-concrete arch and a steel-concrete beam. Background Technology

[0002] In modern bridge and building structures, the combined structure of steel-concrete composite arch and prestressed concrete beam is widely used because it can fully utilize the advantages of both materials. However, when these two structural forms intersect at joint areas, especially when the arch foot and beam end meet at or near the top of the main support column, they often face significant mechanical and structural challenges.

[0003] Reinforced concrete arches transmit enormous axial pressure at the arch foot, while reinforced concrete beams primarily transmit bending moment and shear force, and may generate tensile forces at the beam ends (especially at the bottom chord). These two distinct internal force flows (the pressure flow of the arch and the bending and shear flow of the beam) converge within a confined joint area, easily leading to problems such as stress concentration, unclear force transmission paths, and localized concrete crushing or cracking. Traditional joint connection methods, such as simple rigid connections or simple transition plates, are accompanied by the following problems:

[0004] 1. In a reinforced concrete arch, enormous axial pressure is transmitted at the arch foot, while in a reinforced concrete beam, the lower chord tie rod transmits tensile force. In traditional joints, these two forces tend to concentrate in localized areas, leading to abrupt stress changes.

[0005] 2. The reinforced concrete arch has a circular cross section, while the reinforced concrete beam has a rectangular cross section. Direct connection will lead to abrupt changes in geometry and stiffness, and the internal force transmission will be unsmooth.

[0006] To address this, the present invention provides a transition node structure and design method for the intersection of a steel-concrete arch and a steel-concrete beam. This transition node structure and design method can reconstruct the force transmission path of the steel-concrete arch and the steel-concrete beam to achieve pressure dispersion and orderly transmission of tensile force; it can also achieve a smooth transition in the cross-sectional shape and stiffness of the steel-concrete arch and the steel-concrete beam to prevent abrupt changes in the cross-sectional shape and stiffness of the steel-concrete arch and the steel-concrete beam. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, the present invention provides a transition node structure and design method for the intersection of steel-concrete arch and steel-concrete beam. This structure can reconstruct the force transmission path of the steel-concrete arch and steel-concrete beam to achieve pressure dispersion and orderly transmission of tensile force. It can also achieve a smooth transition in the cross-sectional shape and stiffness of the steel-concrete arch and steel-concrete beam to prevent abrupt changes in the cross-sectional shape and stiffness of the steel-concrete arch and steel-concrete beam.

[0008] The technical solution adopted by this invention to solve its technical problem is: a transition node structure for the intersection of a steel-concrete arch and a steel-concrete beam, wherein the improvement is that the transition node structure for the intersection of the steel-concrete arch and the steel-concrete beam includes a main support column, a steel-concrete beam, a steel-concrete arch, and a transition section; one end of the steel-concrete beam passes through the main support column in a horizontal direction; the end of the steel-concrete arch is fixedly connected to one end of the transition section; and the other end of the transition section is fixedly connected to the steel-concrete beam and the main support column.

[0009] The transition section includes a curved panel, a triangular panel, a first wall panel, a second wall panel, and a vertical rib. The curved panel and the triangular panel are staggered, and the bottom edge of the curved panel is fixedly connected to the end of the reinforced concrete arch. The side edge of the triangular panel is fixedly connected to the side edge of the curved panel. The first wall panel is inserted from one side of the main support column and is fixedly installed between the bottom plate of the triangular panel, the top of the reinforced concrete beam, and the top of the vertical rib. One end of the second wall panel is fixedly connected to the bottom edge of the triangular panel, and the other end is inserted from the top of the reinforced concrete beam. The vertical rib passes through the main support column, and one end of the vertical rib is fixedly connected to one end of the reinforced concrete beam.

[0010] In the above structure, the steel-concrete beam includes a lower chord tie rod, a concrete layer, and prestressed cables. One end of the lower chord tie rod is fixedly connected to one end of the vertical rib plate, and the top of the lower chord tie rod is fixedly connected to the first wall panel. The concrete layer fills the interior of the lower chord tie rod. The prestressed cables pass through the main support column and the concrete layer in a horizontal direction.

[0011] In the above structure, the first wall panel is triangular, one hypotenuse of the first wall panel is fixedly connected to the base of the triangular plate, and the base of the first wall panel is fixedly connected to the top of the lower chord tie rod and the top of the vertical rib plate.

[0012] In the above structure, the second wall panel is rectangular, one end of the second wall panel is fixedly connected to the bottom edge of the triangular plate, and the other end is inserted obliquely into the concrete layer from the top of the lower chord tie rod, and the prestressed cable passes through the second wall panel.

[0013] A design method for a transition node structure where a steel-concrete arch and a steel-concrete beam intersect, the improvement of which is that the design method for the transition node structure where the steel-concrete arch and the steel-concrete beam intersect includes the following steps:

[0014] S10, calculate the axial force at the arch foot of the reinforced concrete arch;

[0015] S20, determine the width of the transition section flare, the thickness of the triangular plate, and the thickness of the curved plate;

[0016] S30, determine the thickness of the vertical rib and the number of prestressed cables;

[0017] S40: Verify whether the concrete strength in the joint area meets the design conditions. If yes, the design is complete; otherwise, return to S30.

[0018] Furthermore, in step S10, the axial force at the arch foot of the reinforced concrete arch is calculated as follows:

[0019] Establish an arch frame model consisting of main supporting columns, reinforced concrete beams, and reinforced concrete arches;

[0020] The arch feet of the reinforced concrete arch are constrained as hinged supports to simulate the constraints imposed on the reinforced concrete arch by the lower chord tie rod and the main support column.

[0021] The axial force at the arch foot of the reinforced concrete arch was calculated using structural analysis software combined with the applied load of the arch frame.

[0022] Furthermore, in step S20, during the process of determining the width of the transition section flare, the thickness of the triangular plate, and the thickness of the curved panel, it is also necessary to verify whether the steel area of ​​the transition section is not less than the circular steel pipe of the steel-concrete arch, the concrete area of ​​the transition section is not less than the concrete area of ​​the steel-concrete arch, and the bearing capacity of the combined section of the transition section is not less than the section bearing capacity of the steel-concrete arch. If not, the width of the transition section flare, the thickness of the triangular plate, and the thickness of the curved panel are re-specified; if yes, proceed to S30.

[0023] Furthermore, in step S30, the specific method for determining the thickness of the vertical rib and the number of prestressed cables is as follows:

[0024] Calculate the tensile force borne by the lower chord tie rod;

[0025] Given the rib thickness, calculate the stress in the vertical ribs;

[0026] The number of prestressed cables is determined based on the tensile force they bear.

[0027] Determine whether the stress in the lower chord tie rod and vertical rib plate is less than the strength of the steel. If yes, proceed to S40; otherwise, recalculate the number of prestressed cables.

[0028] Furthermore, in step S40, the specific steps for verifying whether the concrete strength in the node area meets the design conditions include:

[0029] Calculate the oblique compressive stress in the joint area transmitted from the reinforced concrete arch;

[0030] Calculate the horizontal compressive stress in the nodal area transmitted by the prestressed cable;

[0031] Verify the maximum principal stress in the nodal area;

[0032] Determine whether the concrete strength in the joint area is less than the design value of the concrete compressive strength. If yes, the design is complete; otherwise, the rib thickness needs to be specified again.

[0033] The beneficial effects of this invention are as follows: This invention reconstructs the force transmission path between the steel-concrete arch and the steel-concrete beam through a multi-component structure consisting of a transition section curved panel, a triangular plate, a first wall panel, a second wall panel, and vertical ribs. The curved panel diffuses and transmits the axial pressure of the steel-concrete arch to the triangular plate and the main support column. The vertical ribs directly connect to the lower chord tie rod of the steel-concrete beam, reliably introducing the tensile force at the end of the steel-concrete beam into the node area and transmitting it to the main support column. The first and second wall panels connect the top of the steel-concrete beam and the triangular plate, coordinating the deformation and stress of the steel-concrete beam and the steel-concrete arch. Furthermore, the transition section acts as a steel... The geometric and stiffness transition between the concrete beam and the reinforced concrete arch is facilitated by a curved panel that supports the circular cross-section of the reinforced concrete arch. The triangular plate, the first wall panel, the second wall panel, and the vertical ribs together form a rectangular box structure that transitions to the rectangular cross-section of the reinforced concrete beam. This achieves a smooth transition in the cross-sectional shape and stiffness between the reinforced concrete beam and the reinforced concrete arch. Therefore, this invention can both reconstruct the force transmission path between the reinforced concrete arch and the reinforced concrete beam to achieve distributed pressure and orderly transmission of tensile force, and achieve a smooth transition in the cross-sectional shape and stiffness between the reinforced concrete arch and the reinforced concrete beam to prevent abrupt changes in their cross-sectional shape and stiffness. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of a transition node structure where a steel-concrete arch and a steel-concrete beam intersect, according to the present invention.

[0035] Figure 2 The present invention provides a design method for a transition node structure where a steel-concrete arch and a steel-concrete beam intersect. Figure 1 ;

[0036] Figure 3 The present invention provides a design method for a transition node structure where a steel-concrete arch and a steel-concrete beam intersect. Figure 2 . Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this invention can be combined interactively without contradicting each other.

[0039] Reference Figure 1 As shown, this invention discloses a transition node structure where a steel-concrete arch and a steel-concrete beam intersect. The transition node structure includes a main support column 2, a steel-concrete beam, a steel-concrete arch 1, and a transition section. One end of the steel-concrete beam passes horizontally through the main support column 2. The end of the steel-concrete arch 1 is fixedly connected to one end of the transition section. The other end of the transition section is fixedly connected to both the steel-concrete beam and the main support column 2.

[0040] It should be noted that, in this embodiment, the main support column 2 serves as a load-bearing component of the transition node, used to transfer vertical loads and provide anchorage points for the reinforced concrete beam, the reinforced concrete arch 1, and the transition section; the reinforced concrete beam is a rectangular prestressed reinforced concrete beam, mainly used to bear horizontal loads; the reinforced concrete arch 1 is a circular steel tube arch, mainly used as a compression member, used to convert the load into horizontal thrust and vertical force and transfer them to the reinforced concrete beam and the main support column 2 respectively; it is understood that, due to the difference in cross-sectional geometry between the reinforced concrete arch and the reinforced concrete beam, directly connecting the two would not guarantee the continuity of stress distribution; the design of the transition section can gradually transition the circular structure at the end of the reinforced concrete arch 1 to the rectangular structure at the end of the reinforced concrete beam, ensuring the continuity of stress distribution;

[0041] Furthermore, the transition section includes a curved panel 8, a triangular plate 9, a first wall panel 6, a second wall panel 7, and a vertical rib 10; the curved panel 8 and the triangular plate 9 are staggered, and the bottom edge of the curved panel 8 is fixedly connected to the end of the reinforced concrete arch 1; the side edge of the triangular plate 9 is fixedly connected to the side edge of the curved panel 8; the first wall panel 6 is inserted from one side of the main support column 2, and the first wall panel 6 is fixedly installed between the bottom plate of the triangular plate 9, the top of the reinforced concrete beam, and the top of the vertical rib 10; one end of the second wall panel 7 is fixedly connected to the bottom edge of the triangular plate 9, and the other end is inserted from the top of the reinforced concrete beam; the vertical rib 10 passes through the main support column 2, and one end of the vertical rib 10 is fixedly connected to one end of the reinforced concrete beam.

[0042] It should be noted that in this embodiment, four curved panels 8 are used, and the arc ends of the curved panels 8 are connected to the ends of the steel-concrete arch 1 to transmit the axial pressure of the steel-concrete arch 1, so as to adapt to the curved surface shape of the ends of the steel-concrete arch 1 and convert the curved pressure of the steel-concrete arch 1 into a distributed force perpendicular to the axis of the steel-concrete beam, thus avoiding stress concentration; the triangular plate 9 is used to disperse the concentrated stress transmitted by the curved panels 8, enhance the node stiffness, and the triangle is welded to the curved panels 8 in an alternating manner to form a geometrically stable structure; the first wall plate 6 and the second wall plate 7 are used to connect the steel-concrete beam, the main support column 2 and the triangular plate 9 to form a shear force transmission path; the vertical rib plate 10 penetrates the main support column 2 and is anchored in the steel-concrete beam to resist the horizontal thrust of the arch foot of the steel-concrete arch 1; in the specific implementation of this invention, the transition node structure where the steel-concrete arch and the steel-concrete beam intersect transmits the axial pressure of the steel-concrete arch 1 to the triangular plate 9 and the main support column 1 through the curved panels 8. The main support column 2 and vertical rib plate 10 are directly connected to the end of the reinforced concrete beam, reliably introducing the tensile force at the end of the reinforced concrete beam into the node area and transmitting it to the main support column 2. The first wall plate 6 and the second wall plate 7 connect the top of the reinforced concrete beam and the triangular plate 9, which can coordinate the deformation and stress of the reinforced concrete beam and the reinforced concrete arch 1. In addition, the transition section serves as an intermediary for the gradual change in geometry and stiffness between the reinforced concrete beam and the reinforced concrete arch 1. The curved panel 8 supports the circular cross-section of the reinforced concrete arch 1, while the triangular plate 9, the first wall plate, the second wall plate, and the vertical rib plate 10 together form a rectangular box structure that transitions to the rectangular cross-section of the reinforced concrete beam, so as to achieve a smooth transition in the cross-sectional shape and stiffness between the reinforced concrete beam and the reinforced concrete arch 1. Therefore, the present invention can both reconstruct the force transmission path between the reinforced concrete arch and the reinforced concrete beam to achieve the dispersion of pressure and the orderly transmission of tensile force, and achieve a smooth transition in the cross-sectional shape and stiffness between the reinforced concrete arch and the reinforced concrete beam to prevent abrupt changes in the cross-sectional shape and stiffness between the reinforced concrete arch and the reinforced concrete beam.

[0043] Continue to refer to Figure 1 As shown, the reinforced concrete beam includes a lower chord tie rod 3, a concrete layer 5, and prestressed cables 4. One end of the lower chord tie rod 3 is fixedly connected to one end of the vertical rib plate 10, and the top of the lower chord tie rod 3 is fixedly connected to the first wall panel 6. The concrete layer 5 is filled inside the lower chord tie rod 3. The prestressed cables 4 pass through the main support column 2 and the concrete layer 5 in a horizontal direction.

[0044] It should be noted that, in this embodiment, the lower chord tie rod 3, as the core tensile member of the reinforced concrete beam, is made of high-strength steel (such as alloy steel with a yield strength ≥ 650 MPa) and bears the horizontal tensile force transmitted by the vertical rib plate 10; the concrete filling layer utilizes the compressive strength of concrete (strength grade ≥ C30) to constrain steel deformation and improve cross-sectional stiffness and stability through the steel-concrete interface bond force and mechanical interlocking; the prestressed cable 4 horizontally penetrates the main support column 2 and the concrete layer 5, forming a continuous tensioning path, prestressing... The prestressed cable 4 actively applies prestress to counteract the tensile stress in the concrete caused by external loads, thus inhibiting crack development. In the specific implementation of this invention, the prestressed cable 4 works in conjunction with the lower chord tie rod 3, significantly reducing the self-weight of the structure, making it suitable for large-span structures such as bridges and stadium roofs with spans >30m. The lower chord tie rod 3 is rigidly connected to the vertical rib plate 10, the first wall panel 6, and the second wall panel 7, forming an efficient force transmission path. Furthermore, the prestressed cable 4 can be post-tensioned to compensate for concrete shrinkage and creep losses, ensuring long-term stress stability.

[0045] Continue to refer to Figure 1 As shown, the first wall panel 6 is triangular, and one hypotenuse of the first wall panel 6 is fixedly connected to the base of the triangular plate 9. The base of the first wall panel 6 is fixedly connected to the top of the lower chord tie rod 3 and the top of the vertical rib plate 10. The second wall panel 7 is rectangular, and one end of the second wall panel 7 is fixedly connected to the base of the triangular plate 9. The other end is inserted obliquely into the concrete layer 5 from the top of the lower chord tie rod 3, and the prestressed cable 4 passes through the second wall panel 7.

[0046] It should be noted that in this embodiment, there are three first wall panels 6, and the three first wall panels 6 are arranged parallel to each other between the triangular plate 9 of the transition section and the lower chord tie rod 3 of the steel-concrete beam, forming a rigid triangular region to constrain the relative displacement between the lower chord tie rod 3 and the vertical rib plate 10 and reduce stress concentration in the node area; the second wall panel 7 obliquely penetrates the cross section of the steel-concrete beam, with one end anchored to the bottom edge of the triangular plate 9 and the other end inserted into the concrete layer 5 of the beam, which can convert the arch foot bending moment of the steel-concrete arch 1 into the axial tensile force of the second wall panel 7 and the pressure of the concrete layer 5, thereby reducing the stress at the top of the steel-concrete beam.

[0047] Reference Figure 2 and Figure 3 As shown, this invention also discloses a design method for a transition node structure where a steel-concrete arch and a steel-concrete beam intersect. The design method for the transition node structure where the steel-concrete arch and the steel-concrete beam intersect includes the following steps:

[0048] S10, Calculate the axial force at the arch foot of the reinforced concrete arch 1; specifically, the calculation method for the axial force at the arch foot of the reinforced concrete arch 1 is as follows:

[0049] Establish an arch frame model consisting of main support column 2, reinforced concrete beam, and reinforced concrete arch 1;

[0050] The arch foot of the steel-concrete arch 1 is constrained as a hinged support to simulate the constraint of the lower chord tie rod 3 and the main support column 2 on the steel-concrete arch 1. The horizontal constraint is provided by the lower chord steel-concrete composite beam (the beam structure composed of the lower chord tie rod 3 and the concrete layer 5) and the prestressed cable 4. The vertical constraint is borne independently by the main support column 2.

[0051] The axial force at the arch foot of the reinforced concrete arch 1 was calculated using structural analysis software in conjunction with the applied load of the arch frame; wherein, the applied load of the arch frame specifically includes the self-weight of the arch frame and the load at the top of the arch frame.

[0052] S20, determine the width of the transition section flared opening, the thickness of the triangular plate 9, and the thickness of the curved plate 8; in the process of determining the width of the transition section flared opening, the thickness of the triangular plate 9, and the thickness of the curved plate 8, it is also necessary to verify whether the steel area of ​​the transition section is not less than the circular steel pipe of the steel-concrete arch 1, the concrete area of ​​the transition section is not less than the concrete area of ​​the steel-concrete arch 1, and the bearing capacity of the combined section of the transition section is not less than the section bearing capacity of the steel-concrete arch 1. If not, then re-specify the width of the transition section flared opening, the thickness of the triangular plate 9, and the thickness of the curved plate 8; if yes, then proceed to S30.

[0053] It should be noted that, in this embodiment, the transition section connects to the reinforced concrete arch 1. In determining the parameters of the transition section, it is necessary to compare the steel area, concrete area, and combined section bearing capacity of the transition section with those of the reinforced concrete arch 1 to determine whether the steel bearing capacity, concrete bearing capacity, and overall section bearing capacity of the transition section are all not less than those of the reinforced concrete arch 1. This verifies whether the parameter design of the transition section is qualified. Specifically:

[0054] The ratio of the steel area of ​​the transition section to that of the reinforced concrete arch 1 satisfies the following expression:

[0055] πDt≤2(B×t f1 +D1×t b1 In the formula, D represents the outer diameter of the reinforced concrete arch 1, t represents the wall thickness of the reinforced concrete arch 1, B represents the width of the reinforced concrete beam, and t f1 t represents the thickness of triangular plate 9. b1 D1 represents the thickness of the curved panel 8, and D1 represents the width of the transition section flared end (the end of the structure composed of the triangular plate 9 and the curved panel 8 that is away from the reinforced concrete arch 1).

[0056] The concrete area of ​​the transition section, compared with that of the reinforced concrete arch 1, should satisfy the following expression:

[0057] In the formula, D-2t represents the inner diameter of the steel-concrete arch 1;

[0058] The bearing capacity of the transition section composite section corresponds to the steel-concrete arch 1 and satisfies the following expression:

[0059] In the formula, This indicates the cross-sectional bearing capacity of reinforced concrete arch 1. Indicates the bearing capacity of the composite section of the transition section;

[0060] Furthermore, and The calculation requires using the general formula for bearing capacity from the technical specifications:

[0061] N0 = A sc f sc In the formula, N0 represents the design value of the axial compressive strength bearing capacity of the concrete-filled steel tube short column, and A represents... sc f represents the total cross-sectional area of ​​the concrete-filled steel tube member. sc This indicates the design value of the compressive strength of concrete-filled steel tubular concrete, specifically:

[0062] f sc = (1.212+Eθ+Fθ) 2 )f c In the formula, E and F represent the influence coefficients of the cross-sectional shape on the hoop effect. For a solid circular cross-section steel pipe: E = 0.176f / 213 + 0.974, F = -0.070f c / 14.4+0.031, for a solid square cross-section steel pipe: E=0.131f / 213+0.723, F=-0.070f c / 14.4+0.026; f c This represents the design value of the compressive strength of the concrete; θ represents the confinement coefficient; further:

[0063] In the formula, A s A represents the area of ​​the steel pipe. c α represents the area of ​​concrete inside the steel pipe. sc This indicates the steel content; f represents the design compressive strength of the steel.

[0064] In the specific comparison process, simply substitute the parameters of the reinforced concrete arch 1 and the transition section into the aforementioned general formula for bearing capacity to calculate the result. and Then you can compare them.

[0065] S30, determine the thickness of the vertical rib plate 10 and the number of prestressed cables 4; specifically, the method for determining the thickness of the vertical rib plate 10 and the number of prestressed cables 4 is as follows:

[0066] Calculate the tensile force borne by the lower chord tie rod 3;

[0067] Given the thickness of rib 10, calculate the stress in the vertical rib 10;

[0068] The number of prestressed cables 4 is determined based on the tensile force borne by the prestressed cable 4;

[0069] Determine whether the stress of the lower chord tie rod 3 and the vertical rib plate 10 is less than the strength of the steel. If yes, proceed to S40; otherwise, recalculate the number of prestressed cables 4.

[0070] It should be noted that, in this embodiment, the forces acting on the arch feet of the reinforced concrete arch 1 must strictly satisfy the equilibrium equations:

[0071] N×cosα=N S +N p In the formula, N represents the axial force at the arch foot of the reinforced concrete arch 1, α represents the clamping force between the arch foot and the horizontal direction, and N represents the axial force at the arch foot. S The tensile force (N) borne by the lower chord steel-concrete composite beam p For the tension of prestressed cable 4; specifically:

[0072] N P =n×A P ×f p,con In the formula, n represents the number of prestressed cables 4, and A p f represents the cross-sectional area of ​​a single prestressed cable 4; p,con This indicates the tension control stress of prestressed cable 4;

[0073] N S =A S1 ×f y,con In the formula, A S1 f represents the steel area of ​​the lower chord steel-concrete composite beam. y,con Steel design to control stress;

[0074] To determine whether the stress in the lower chord tie rod 3 and the vertical rib plate 10 is less than the steel strength, the following formula should be satisfied:

[0075] In the formula, m represents the number of ribs 10, H represents the height of ribs 10, and t2 represents the thickness of ribs 10; f y Indicates the ultimate tensile strength of steel;

[0076] S40, verify whether the concrete strength of the joint area meets the design conditions. If yes, the design is complete; otherwise, return to S30. The specific steps for verifying whether the concrete strength of the joint area meets the design conditions include:

[0077] Calculate the oblique compressive stress in the joint area transmitted from the reinforced concrete arch 1; the calculation formula is as follows:

[0078] In the formula, σ α Indicates oblique compressive stress; A c1 A represents the concrete area of ​​reinforced concrete arch 1; s2E represents the area of ​​steel used in the reinforced concrete arch 1; s E represents the elastic modulus of steel. c Indicates the elastic modulus of concrete;

[0079] Calculate the horizontal compressive stress in the nodal area transmitted by prestressed cable 4; the calculation formula is as follows:

[0080] In the formula, σ x Indicates horizontal compressive stress; A b,c Indicates the concrete area of ​​the joint area; A b,s This indicates the area of ​​the first wall panel (6 steel sections) in section 3;

[0081] Verify the maximum principal stress in the nodal region; the calculation expression is as follows:

[0082] In the formula, σ1 represents the maximum compressive principal stress, and its corresponding maximum force direction angle is:

[0083] Determine whether the concrete strength in the joint area is less than the design value of the concrete compressive strength f. c If so, the design is complete; otherwise, the rib thickness 10 needs to be specified again.

[0084] It should be noted that, in this embodiment, the transition node structure at the intersection of the steel-concrete arch and the steel-concrete beam designed by the above design method can not only reconstruct the force transmission path of the steel-concrete arch and the steel-concrete beam to achieve pressure dispersion and orderly transmission of tension; it can also achieve a smooth transition in the cross-sectional shape and stiffness of the steel-concrete arch 1 and the steel-concrete beam to prevent abrupt changes in the cross-sectional shape and stiffness of the steel-concrete arch and the steel-concrete beam.

[0085] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A transition node structure for the intersection of a reinforced concrete arch and a reinforced concrete beam, characterized in that, The transition node structure where the steel-concrete arch and the steel-concrete beam intersect includes a main support column, a steel-concrete beam, a steel-concrete arch, and a transition section; one end of the steel-concrete beam passes through the main support column in a horizontal direction; the end of the steel-concrete arch is fixedly connected to one end of the transition section; the other end of the transition section is fixedly connected to the steel-concrete beam and the main support column. The transition section includes a curved panel, a triangular panel, a first wall panel, a second wall panel, and vertical ribs; the curved panel and the triangular panel are staggered, and the bottom edge of the curved panel is fixedly connected to the end of the reinforced concrete arch; the side edge of the triangular panel is fixedly connected to the side edge of the curved panel; the first wall panel is inserted from one side of the main support column, and the first wall panel is fixedly installed between the bottom plate of the triangular panel, the top of the reinforced concrete beam, and the top of the vertical ribs; one end of the second wall panel is fixedly connected to the bottom edge of the triangular panel, and the other end is inserted from the top of the reinforced concrete beam; the vertical ribs pass through the main support column, and one end of the vertical ribs is fixedly connected to one end of the reinforced concrete beam; The reinforced concrete beam includes a lower chord tie rod, a concrete layer, and prestressed tendons. One end of the lower chord tie rod is fixedly connected to one end of a vertical rib plate, and the top of the lower chord tie rod is fixedly connected to the first wall panel. The concrete layer fills the interior of the lower chord tie rod. The prestressed tendons pass through the main support column and the concrete layer in a horizontal direction.

2. The transition node structure at the intersection of a reinforced concrete arch and a reinforced concrete beam according to claim 1, characterized in that, The first wall panel is triangular, with one hypotenuse of the first wall panel fixedly connected to the base of the triangular plate, and the base of the first wall panel fixedly connected to the top of the lower chord tie rod and the top of the vertical rib plate.

3. The transition node structure at the intersection of a reinforced concrete arch and a reinforced concrete beam according to claim 1, characterized in that, The second wall panel is rectangular. One end of the second wall panel is fixedly connected to the bottom edge of the triangular plate, and the other end is inserted obliquely into the concrete layer from the top of the lower chord tie rod, and the prestressed cable passes through the second wall panel.

4. A design method for a transition node structure where a reinforced concrete arch and a reinforced concrete beam intersect, characterized in that, The design method for the transition node structure where the steel-concrete arch and the steel-concrete beam intersect includes the following steps: S10, calculate the axial force at the arch foot of the reinforced concrete arch; S20, determine the width of the transition section flare, the thickness of the triangular plate, and the thickness of the curved plate; S30, determine the thickness of the vertical rib and the number of prestressed cables; S40: Verify whether the concrete strength in the joint area meets the design conditions. If yes, the design is complete; otherwise, return to S30.

5. The design method for a transition node structure where a reinforced concrete arch and a reinforced concrete beam intersect, as described in claim 4, is characterized in that... In step S10, the axial force at the arch foot of the reinforced concrete arch is calculated as follows: Establish an arch frame model consisting of main supporting columns, reinforced concrete beams, and reinforced concrete arches; The arch feet of the reinforced concrete arch are constrained as hinged supports to simulate the constraints imposed on the reinforced concrete arch by the lower chord tie rod and the main support column; The axial force at the arch foot of the reinforced concrete arch was calculated using structural analysis software combined with the applied load of the arch frame.

6. The design method for a transition node structure where a reinforced concrete arch and a reinforced concrete beam intersect, as described in claim 4, is characterized in that... In step S20, during the process of determining the width of the transition section flare, the thickness of the triangular plate, and the thickness of the curved plate, it is also necessary to verify whether the steel area of ​​the transition section is not less than the circular steel pipe of the steel-concrete arch, the concrete area of ​​the transition section is not less than the concrete area of ​​the steel-concrete arch, and the bearing capacity of the combined section of the transition section is not less than the section bearing capacity of the steel-concrete arch. If not, the width of the transition section flare, the thickness of the triangular plate, and the thickness of the curved plate are re-specified. If yes, proceed to S30.

7. The design method for a transition node structure where a steel-concrete arch and a steel-concrete beam intersect, as described in claim 4, is characterized in that... In step S30, the specific method for determining the thickness of the vertical rib and the number of prestressed cables is as follows: Calculate the tensile force borne by the lower chord tie rod; Given the rib thickness, calculate the stress in the vertical ribs; The number of prestressed cables is determined based on the tensile force they bear. Determine whether the stress in the lower chord tie rod and vertical rib plate is less than the strength of the steel. If yes, proceed to S40; otherwise, recalculate the number of prestressed cables.

8. The design method for a transition node structure where a steel-concrete arch and a steel-concrete beam intersect, as described in claim 4, is characterized in that... In step S40, the specific steps for verifying whether the concrete strength in the joint area meets the design conditions include: Calculate the oblique compressive stress in the joint area transmitted from the reinforced concrete arch; Calculate the horizontal compressive stress in the nodal area transmitted by the prestressed cable; Verify the maximum principal stress in the nodal area; Determine whether the concrete strength in the joint area is less than the design value of the concrete compressive strength. If yes, the design is complete; otherwise, the rib thickness needs to be specified again.

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