Double-limb steel reinforced concrete thin-wall pier suitable for high-intensity area and design method of double-limb steel reinforced concrete thin-wall pier

Abstract

The invention discloses a double-limb steel reinforced concrete thin-wall pier suitable for a high-intensity area and a design method of the double-limb steel reinforced concrete thin-wall pier, and relates to the field of bridge construction design. The combined framework is arranged in the single-limb pier of the pier body; the combined framework comprises profile steel and longitudinal steel plates, the profile steel is arranged on the two sides of the interior of the single-limb pier in the width direction of the single-limb pier, and the profile steel is fixedly connected with main ribs in the single-limb pier; the two sides of the longitudinal steel plate are welded to the two pieces of profile steel respectively, and the longitudinal steel plate is parallel to the width direction of the single-limb pier; and the length directions of the profile steel and the longitudinal steel plates are arranged along the height direction of the single-limb pier. By adopting the scheme, the double-limb steel reinforced concrete thin-wall pier has good bending resistance and torsion resistance through the bending resistance of the section steel in the combined framework and the shearing resistance of the longitudinal steel plates, and the stability of the pier is ensured; meanwhile, due to the high toughness of the steel, the double-limb type steel thin-wall pier shows good anti-seismic performance under the action of an earthquake.

Description

Technical Field

[0001] This invention relates to the field of bridge construction design, specifically to a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones and its design method. Background Technology

[0002] For long-span continuous rigid frame bridges, double-limb reinforced concrete thin-walled piers are commonly used, exhibiting high flexural stiffness in the longitudinal direction. When subjected to vertical loads from the superstructure, these piers effectively resist bending moments, ensuring pier stability. Simultaneously, they also possess good torsional resistance in the transverse direction. Due to the spacing between the two limbs, they can work together to resist torque, reducing torsional deformation. For continuous rigid frame bridges with pier heights exceeding 50m, the double-limb thin-walled pier structure is relatively sensitive to temperature changes and concrete shrinkage and creep. However, because the lateral stiffness of the double-limb thin-walled pier is much lower than that of a box pier, it can, to some extent, reduce the additional internal forces generated by temperature and shrinkage / creep through deformation coordination between the two limbs. In statically indeterminate structures like continuous rigid frame bridges, reducing these additional internal forces is crucial for the long-term performance and safety of the structure.

[0003] However, in high-intensity earthquake zones, due to the relatively low stiffness of double-limb thin-walled piers, they may experience significant displacement during high-intensity earthquakes. This significant displacement may lead to damage at the connection between the bridge beam and the pier. Simultaneously, large displacements can also damage ancillary facilities such as expansion joints, affecting the normal use of the bridge. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention aims to provide a double-limb steel-concrete thin-walled pier and its design method suitable for high-intensity seismic zones. By combining the bending resistance of the steel in the frame with the shear resistance of the longitudinal steel plates, the double-limb steel-concrete thin-walled pier possesses excellent bending and torsional resistance, ensuring the stability of the pier. Simultaneously, the high toughness of the steel enables the double-limb steel thin-walled pier to exhibit good seismic performance under earthquake loading.

[0005] This invention is achieved through the following technical solution: A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones, comprising: Pier body; A composite frame, wherein the composite frame is disposed inside the single-limb pier of the pier body; The composite frame includes structural steel and longitudinal steel plates. Structural steel is provided on both sides of the single-limb pier along its own width direction. The structural steel is fixedly connected to the main reinforcement inside the single-limb pier. The longitudinal steel plate is welded to two of the steel sections on both sides, and the longitudinal steel plate is parallel to the width direction of the single-limb pier. The length of both the structural steel and the longitudinal steel plate is along the height direction of the single-limb pier.

[0006] Compared to existing technologies, which may lead to significant displacement during high-intensity earthquakes due to the relatively low stiffness of double-limb thin-walled piers, this invention provides a double-limb steel-concrete thin-walled pier suitable for high-intensity earthquake zones. Each limb of the pier incorporates a composite frame comprising two steel sections and a longitudinal steel plate. The two steel sections are positioned on opposite sides to enhance the pier's bending resistance, while the longitudinal steel plate connects them to improve torsional resistance. This combination results in excellent bending and torsional resistance, ensuring the pier's stability. Furthermore, the high toughness of steel contributes to the pier's superior seismic performance. During an earthquake, the double-limb steel thin-walled pier absorbs some seismic energy through deformation, reducing structural damage. The coordinated action between the two limbs also helps disperse seismic forces, effectively controlling the pier's seismic response. Compared to concrete piers, steel thin-walled piers exhibit increased load-bearing capacity, better ductility, and are less prone to brittle failure during earthquakes. In addition, the steel content within the pier body needs to be controlled between 5% and 10%, and several adjacent stiffening ribs with a spacing of ≤1500mm should be installed to address the local buckling problem of thin-walled steel. Furthermore, a "steel-concrete composite transition section" is set at the connection between the crossbeam and the double limbs, with the steel in the crossbeam extending to a range three times the height of the steel in the pier body. 5% steel fiber is added to the concrete in the joint area, increasing the shear strength by 30%.

[0007] Furthermore, the combined frame is symmetrically arranged along the centerline of the width direction of the single limb pier.

[0008] In a further optimization, the steel section is made of I-beams, and the two sides of the longitudinal steel plate are welded to the webs of the two I-beams respectively.

[0009] Further optimization involves vertically welding several studs to both the flanges and web of the steel section, with the shank ends of the studs welded to the steel section. Specifically, the stud diameter is ≥16mm, the length is not less than 4 times the stud diameter, the spacing between adjacent studs is not greater than 300mm and 7.5 times the stud diameter, and the distance from the stud to the edge of the longitudinal steel plate is not less than 50mm, resulting in an increase of over 40% in the interface shear capacity.

[0010] Furthermore, the composite frame is further optimized by including several stiffening ribs. The spacing between adjacent stiffening ribs is ≤1500mm. Additionally, both the upper and lower ends of the composite frame extend into the top and bottom bearing platforms, respectively, with a embedment depth ≥3H.

[0011] Further optimization includes a connecting sleeve, which is welded to and fitted onto the main reinforcement bars, and the end of the connecting sleeve is welded to the steel section. The connecting sleeve enables effective connection; the main reinforcement bars of the pier are welded in the factory via the connecting sleeve, and the weld between the sleeve and the steel section inside the thin-walled pier is connected to the reinforcing bars in the connected beam with equal strength.

[0012] Further solutions: This invention also provides a design method for double-limb steel-concrete thin-walled piers suitable for high-intensity seismic zones, comprising the following steps: The superposition method was used to calculate the bearing capacity of the composite section in the double-limb steel-concrete thin-walled pier, and to determine whether the bearing capacity calculation results met the bearing capacity requirements. The bearing capacity calculation included verification of the normal section compression-bending member and verification of the shear resistance of the inclined section. At the same time, the overall stability calculation of the double-limb steel-concrete thin-walled pier was carried out.

[0013] To further optimize the process, the superposition method is used to perform positive section compression-bending member verification on the composite section within the double-limb steel-concrete thin-walled pier. The specific steps to determine whether the calculated bearing capacity meets the bearing capacity requirements include: First, the double-limb steel-concrete thin-walled pier is treated as an eccentrically compressed member, with the relative height of the boundary compression zone as the reference. Determine the cross-sectional size of an eccentrically compressed member using the following formula: when When it is a member under large eccentric compression, take ; when > When it is a member under small eccentric compression, take ; in, ; - The ratio of the height of the rectangular stress diagram of the compression zone to the actual height of the compression zone; - The ultimate compressive strain of concrete under non-uniform compression; - The elastic modulus of longitudinal reinforcement; - Standard value of tensile strength of structural steel; - Standard value of tensile strength of structural steel; - Equivalent compression zone height in the stress diagram of the compression zone of the section; h0 - Distance from the edge of the section with greater compression to the point of action of the resultant force between the steel reinforcement and the steel section on the tension side or the side with less compression, h0=ha; Subsequently, based on the discrimination results, the compressive bearing capacity of the eccentrically compressed member is calculated and conforms to the following formula: ; ; when hour, , , ; when hour, , , , ; in, - Importance coefficient of bridge structure; -Standard value of axial force in a double-limb thin-walled pier caused by structural dead load; -Standard value of axial force in a double-limb thin-walled pier caused by seismic action; -Standard value of concrete tensile strength for double-limb thin-walled piers; - Standard value of compressive strength of structural steel; -The total cross-sectional area of ​​all longitudinal steel reinforcements in the belly of the double-limb thin-walled pier; -The total longitudinal steel plate cross-sectional area configured on the belly of the double-limb thin-walled pier; -Standard value of axial force borne by all longitudinal reinforcements in the web of the double-limb thin-walled pier; -Standard value of axial force borne by all longitudinal steel plates configured in the belly of the double-limb thin-walled pier; -Standard value of the moment of all longitudinal reinforcement internal forces in the web of the double-limb thin-walled pier about the centroid of the longitudinal reinforcement on the tension side or the side with less compression of the cross section; -Standard value of the moment of all longitudinal steel plates in the belly of the double-limb thin-walled pier about the centroid of the tension side or the smaller compression side of the cross section; - Height of the longitudinal reinforcement section along the web of the cross section; - The ratio of the height of the longitudinal reinforcement section along the web of the cross section to the effective height of the cross section; - The ratio of the height of the longitudinal steel plate section arranged along the web of the cross section to the effective height of the cross section; -Standard values ​​of tensile strength of all longitudinal steel plates configured in the belly of the double-limb thin-walled pier; - Standard value of tensile strength of all longitudinal steel bars in the web of the double-limb thin-walled pier; e - Distance from the point of application of axial force to the point of application of the resultant force of the tension steel and longitudinal tension steel bars.

[0014] To further optimize, when performing shear resistance verification of inclined sections, the shear capacity of the inclined section should conform to the following formula: ; ; ; ; in, -Standard value of shear force of double-limb thin-walled pier caused by structural dead load; -Standard value of shear force of double-limb thin-walled pier caused by seismic action; - Considering the beneficial effect of axial pressure on shear resistance, the standard value of shear bearing capacity of concrete and stirrups working together in the inclined section of the double-limb thin-walled pier; -The standard value of shear force borne by all the steel sections configured at one end of the double-limb thin-walled pier; - The standard value of shear force borne by all steel plates in the double-limb thin-walled pier configuration; -The standard value of the shear force borne by the double-limb thin-walled pier is taken as... ; , - Width and height of thin-walled pier section; - Standard value of tensile strength of structural steel; -The cross-sectional area of ​​the steel section at one end of the double-limb thin-walled pier can be taken as the smaller value of the cross-sectional areas of the steel sections at both ends; -Calculate the shear span ratio of the interface. ,Pick ; - The reinforcement ratio of longitudinal tensile reinforcement and steel plate within the inclined section. ,Pick ; - Cross-sectional area of ​​the tension steel section of the double-limb thin-walled pier; - Cross-sectional area of ​​tensile reinforcement in double-limb thin-walled piers; - Standard value of compressive strength of a concrete cube with a side length of 150mm; - Reinforcement ratio of stirrups in the inclined section of a double-limb thin-walled pier; -Standard value of tensile strength of stirrups in inclined section of double-limb thin-walled pier.

[0015] To further optimize the overall stability calculation, the shear section of the double-limb steel-concrete thin-walled pier should conform to the following formula: .

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides a double-limb steel-concrete thin-walled pier and its design method suitable for high-intensity seismic zones. Utilizing the inherent mechanical properties of steel, the double-limb steel thin-walled pier possesses excellent bending and torsional resistance, ensuring pier stability. Simultaneously, the high toughness of steel enables the double-limb steel thin-walled pier to exhibit good seismic performance under earthquake loading. During an earthquake, the double-limb steel thin-walled pier can absorb some seismic energy through its own deformation, reducing the damage to the structure; moreover, the coordinated work between the two limbs helps to disperse seismic forces, effectively controlling the pier's seismic response. Compared to concrete piers, steel thin-walled piers have improved load-bearing capacity and better ductility during earthquakes, and are less prone to brittle failure. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 A top cross-sectional view of a single-limb pier provided for this invention; Figure 2 This is a schematic diagram of the position of the stud provided by the present invention; Figure 3 This is a schematic diagram showing the position of the connecting sleeve provided by the present invention; Figure 4 A schematic diagram illustrating the calculation parameters for the compressive bearing capacity of the eccentrically compressed positive section of the double-limb steel-concrete thin-walled pier provided by this invention.

[0018] The attached diagram shows the markings and corresponding component names: 1-Single-limb block, 2-Combined frame, 201-Steel section, 202-Longitudinal steel plate, 203-Stud, 204-Stiffening rib, 205-Connecting sleeve. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1: This Example 1 provides a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones, such as... Figures 1-3 As shown, it includes: Pier body; A composite frame 2 is disposed inside the single-limb pier 1 of the pier body; The combined frame 2 includes structural steel 201 and longitudinal steel plate 202. Structural steel 201 is provided on both sides of the single limb pier 1 along its own width direction. The structural steel 201 is fixedly connected to the main reinforcement inside the single limb pier 1. The longitudinal steel plate 202 is welded to two sections of steel 201 on both sides, and the longitudinal steel plate 202 is parallel to the width direction of the single-limb pier 1. The length direction of the steel section 201 and the longitudinal steel plate 202 are both set along the height direction of the single-limb pier 1.

[0021] Compared to existing technologies, in high-intensity seismic zones, the relatively low stiffness of double-limb thin-walled piers can lead to significant displacement during earthquakes. This invention provides a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones. Each limb pier 1 incorporates a composite frame 2, comprising two steel sections 201 and a longitudinal steel plate 202. The two steel sections 201 are positioned on opposite sides to improve the pier's bending resistance, while the longitudinal steel plate 202 connects them to enhance torsional resistance. This results in a double-limb steel thin-walled pier with excellent bending and torsional resistance, ensuring pier stability. Furthermore, the high toughness of the steel contributes to the pier's superior seismic performance. During an earthquake, the double-limb steel thin-walled pier absorbs some seismic energy through its own deformation, reducing structural damage. The coordinated action between the two limbs also helps disperse seismic forces, effectively controlling the pier's seismic response. Compared to concrete piers, thin-walled steel piers exhibit improved load-bearing capacity and better ductility during earthquakes, making them less prone to brittle failure. Furthermore, the steel content within the pier body must be controlled between 5% and 10%, and several adjacent stiffening ribs (204) with a spacing ≤1500mm should be installed to address the local buckling problem of the thin-walled steel. Additionally, a "steel-concrete composite transition section" is incorporated at the connection between the crossbeam and the double limbs, with the steel within the crossbeam extending to a range three times the height of the pier body (201). The concrete in the joint area incorporates 5% steel fiber, increasing shear strength by 30%.

[0022] In this embodiment, the combined frame 2 is symmetrically arranged along the centerline of the width direction of the single limb pier 1.

[0023] In this embodiment, the steel section 201 is an I-beam, and the two sides of the longitudinal steel plate 202 are welded to the webs of the two I-beams respectively.

[0024] In this embodiment, a plurality of studs 203 are vertically welded to both the flanges and web of the steel section 201, and the ends of the studs 203 are welded to the steel section 201. The studs 203 have a diameter ≥ 16 mm, a length not less than 4 times the stud diameter, a spacing between adjacent studs 203 not greater than 300 mm and 7.5 times the stud diameter, and a distance from the studs 203 to the edge of the longitudinal steel plate 202 not less than 50 mm, resulting in an increase of over 40% in the interface shear capacity.

[0025] In this embodiment, the combined frame 2 is further provided with a plurality of stiffening ribs 204. The spacing between adjacent stiffening ribs 204 is ≤1500mm. Furthermore, both the upper and lower ends of the combined frame 2 extend into the top and bottom supports, respectively, with a embedment depth ≥3H.

[0026] In this embodiment, a connecting sleeve 205 is also included. The connecting sleeve 205 is welded and sleeved onto the main reinforcement, and the end of the connecting sleeve 205 is welded to the steel section 201. The connecting sleeve 205 enables effective connection. The main reinforcement of the pier body is welded in the factory via the connecting sleeve 205, and the weld between the sleeve and the steel section 201 inside the thin-walled pier is connected to the reinforcing bars in the connected beam with equal strength.

[0027] Example 2: This Example 2 is an optimization based on Example 1, providing a design method for double-limb steel-concrete thin-walled piers suitable for high-intensity seismic zones.

[0028] The specific design calculation methods include: using the superposition method to calculate the bearing capacity of the steel-concrete composite section, including verification of the positive section compression-bending member and the oblique section shear resistance, to ensure that the steel and concrete do not delaminate. At the same time, the overall stability of the double-limb pier is verified, taking into account the influence of the slenderness ratio of the pier column, and the bearing capacity is reduced by a stability coefficient.

[0029] Please see Figure 4 In this embodiment, the superposition method is used to perform positive section compression-bending member verification on the composite section of the double-limb steel-concrete thin-walled pier, and the specific steps to determine whether the calculated bearing capacity meets the bearing capacity requirements include: First, the double-limb steel-concrete thin-walled pier is treated as an eccentrically compressed member, with the relative height of the boundary compression zone as the reference. Determine the cross-sectional size of an eccentrically compressed member using the following formula: when When it is a member under large eccentric compression, take ; when > When it is a member under small eccentric compression, take ; in, ; - The ratio of the height of the rectangular stress diagram of the compression zone to the actual height of the compression zone; - The ultimate compressive strain of concrete under non-uniform compression; - The elastic modulus of longitudinal reinforcement; - Standard value of tensile strength of structural steel; - Standard value of tensile strength of structural steel; - Equivalent compression zone height in the stress diagram of the compression zone of the section; h0 - Distance from the edge of the section with greater compression to the point of action of the resultant force between the steel reinforcement and the steel section on the tension side or the side with less compression, h0=ha; Subsequently, based on the discrimination results, the compressive bearing capacity of the eccentrically compressed member is calculated and conforms to the following formula: ; ; when hour, , , ; when hour, , , , ; in, - Importance coefficient of bridge structure; -Standard value of axial force in a double-limb thin-walled pier caused by structural dead load; -Standard value of axial force in a double-limb thin-walled pier caused by seismic action; -Standard value of concrete tensile strength for double-limb thin-walled piers; - Standard value of compressive strength of structural steel; -The total cross-sectional area of ​​all longitudinal steel reinforcements in the belly of the double-limb thin-walled pier; -The total longitudinal steel plate cross-sectional area configured on the belly of the double-limb thin-walled pier; -Standard value of axial force borne by all longitudinal reinforcements in the web of the double-limb thin-walled pier; -Standard value of axial force borne by all longitudinal steel plates configured in the belly of the double-limb thin-walled pier; -Standard value of the moment of all longitudinal reinforcement internal forces in the web of the double-limb thin-walled pier about the centroid of the longitudinal reinforcement on the tension side or the side with less compression of the cross section; -Standard value of the moment of all longitudinal steel plates in the belly of the double-limb thin-walled pier about the centroid of the tension side or the smaller compression side of the cross section; - Height of the longitudinal reinforcement section along the web of the cross section; - The ratio of the height of the longitudinal reinforcement section along the web of the cross section to the effective height of the cross section; - The ratio of the height of the longitudinal steel plate section arranged along the web of the cross section to the effective height of the cross section; -Standard values ​​of tensile strength of all longitudinal steel plates configured in the belly of the double-limb thin-walled pier; - Standard value of tensile strength of all longitudinal steel bars in the web of the double-limb thin-walled pier; e - Distance from the point of application of axial force to the point of application of the resultant force of the tension steel and longitudinal tension steel bars.

[0030] In this embodiment, when performing shear resistance verification of the inclined section, the shear bearing capacity of the inclined section should conform to the following formula: ; ; ; ; in, -Standard value of shear force of double-limb thin-walled pier caused by structural dead load; -Standard value of shear force of double-limb thin-walled pier caused by seismic action; - Considering the beneficial effect of axial pressure on shear resistance, the standard value of shear bearing capacity of concrete and stirrups working together in the inclined section of the double-limb thin-walled pier; -The standard value of shear force borne by all the steel sections configured at one end of the double-limb thin-walled pier; - The standard value of shear force borne by all steel plates in the double-limb thin-walled pier configuration; -The standard value of the shear force borne by the double-limb thin-walled pier is taken as... ; , - Width and height of thin-walled pier section; - Standard value of tensile strength of structural steel; -The cross-sectional area of ​​the steel section at one end of the double-limb thin-walled pier can be taken as the smaller value of the cross-sectional areas of the steel sections at both ends; -Calculate the shear span ratio of the interface. ,Pick ; - The reinforcement ratio of longitudinal tensile reinforcement and steel plate within the inclined section. ,Pick ; - Cross-sectional area of ​​the tension steel section of the double-limb thin-walled pier; - Cross-sectional area of ​​tensile reinforcement in double-limb thin-walled piers; - Standard value of compressive strength of a concrete cube with a side length of 150mm; - Reinforcement ratio of stirrups in the inclined section of a double-limb thin-walled pier; -Standard value of tensile strength of stirrups in inclined section of double-limb thin-walled pier.

[0031] In this embodiment, when performing overall stability calculations, the shear section of the double-limb steel-concrete thin-walled pier should conform to the following formula: .

[0032] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones, characterized in that, include: Pier body; A composite frame (2) is disposed inside the single-limb pier (1) of the pier body; The combined frame (2) includes steel profiles (201) and longitudinal steel plates (202). The single-limb pier (1) is provided with steel profiles (201) on both sides along its width direction. The steel profiles (201) and the main reinforcement bars inside the single-limb pier (1) are fixedly connected. The longitudinal steel plate (202) is welded to two sections of steel (201) on both sides, and the longitudinal steel plate (202) is parallel to the width direction of the single-limb block (1); The length direction of the steel section (201) and the longitudinal steel plate (202) are both set along the height direction of the single-limb block (1).

2. A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 1, characterized in that, The combined frame (2) is symmetrically arranged along the centerline of the width direction of the single limb pier (1).

3. A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 1, characterized in that, The steel section (201) is made of I-beams, and the longitudinal steel plate (202) is welded to the webs of two I-beams on both sides respectively.

4. A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 1, characterized in that, Several studs (203) are vertically welded to the flanges and webs of the steel section (201), and the ends of the studs (203) are welded to the steel section (201).

5. A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 1, characterized in that, The composite frame (2) is also provided with several stiffening ribs (204).

6. A double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 1, characterized in that, It also includes a connecting sleeve (205), which is welded and sleeved on the main reinforcement, and the end of the connecting sleeve (205) is welded to the section steel (201).

7. A design method for a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones, as described in any one of claims 1 to 6, characterized in that... Includes the following steps: The superposition method was used to calculate the bearing capacity of the composite section in the double-limb steel-concrete thin-walled pier, and to determine whether the bearing capacity calculation results met the bearing capacity requirements. The bearing capacity calculation included verification of the normal section compression-bending member and verification of the shear resistance of the inclined section. At the same time, the overall stability calculation of the double-limb steel-concrete thin-walled pier was carried out.

8. The design method for a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 7, characterized in that, The specific steps for verifying the positive section compression-bending member of the composite section within a double-limb steel-concrete thin-walled pier using the superposition method, and determining whether the calculated bearing capacity meets the specified requirements, include: First, the double-limb steel-concrete thin-walled pier is treated as an eccentrically compressed member, with the relative height of the boundary compression zone as the reference. Determine the cross-sectional size of an eccentrically compressed member using the following formula: when When it is a member under large eccentric compression, take ; when > When it is a member under small eccentric compression, take ; in, ; - The ratio of the height of the rectangular stress diagram of the compression zone to the actual height of the compression zone; - The ultimate compressive strain of concrete under non-uniform compression; - The elastic modulus of longitudinal reinforcement; - Standard value of tensile strength of structural steel; - Standard value of tensile strength of structural steel; - Equivalent compression zone height in the stress diagram of the compression zone of the section; h0 - Distance from the edge of the section with greater compression to the point of action of the resultant force between the steel reinforcement and the steel section on the tension side or the side with less compression, h0=ha; Subsequently, based on the discrimination results, the compressive bearing capacity of the eccentrically compressed member is calculated and conforms to the following formula: ； ； when hour, , , ; when hour, , , , ; in, - Importance coefficient of bridge structure; -Standard value of axial force in a double-limb thin-walled pier caused by structural dead load; -Standard value of axial force in a double-limb thin-walled pier caused by seismic action; -Standard value of concrete tensile strength for double-limb thin-walled piers; - Standard value of compressive strength of structural steel; -The total cross-sectional area of ​​all longitudinal steel reinforcements in the belly of the double-limb thin-walled pier; -The total longitudinal steel plate cross-sectional area configured on the belly of the double-limb thin-walled pier; -Standard value of axial force borne by all longitudinal reinforcements in the web of the double-limb thin-walled pier; -Standard value of axial force borne by all longitudinal steel plates configured in the belly of the double-limb thin-walled pier; -Standard value of the moment of all longitudinal reinforcement internal forces in the web of the double-limb thin-walled pier about the centroid of the longitudinal reinforcement on the tension side or the side with less compression of the cross section; -Standard value of the moment of all longitudinal steel plates in the belly of the double-limb thin-walled pier about the centroid of the tension side or the smaller compression side of the cross section; - Height of the longitudinal reinforcement section along the web of the cross section; - The ratio of the height of the longitudinal reinforcement section along the web of the cross section to the effective height of the cross section; - The ratio of the height of the longitudinal steel plate section arranged along the web of the cross section to the effective height of the cross section; -Standard values ​​of tensile strength of all longitudinal steel plates configured in the belly of the double-limb thin-walled pier; - Standard value of tensile strength of all longitudinal steel bars in the web of the double-limb thin-walled pier; e- Distance from the point of application of axial force to the point of application of the resultant force of the tension steel and longitudinal tension steel bars.

9. The design method for a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 7, characterized in that, When performing shear resistance verification of inclined sections, the shear capacity of the inclined section should conform to the following formula: ； ； ； ； in, -Standard value of shear force of double-limb thin-walled pier caused by structural dead load; -Standard value of shear force of double-limb thin-walled pier caused by seismic action; - Considering the beneficial effect of axial pressure on shear resistance, the standard value of shear bearing capacity of concrete and stirrups working together in the inclined section of the double-limb thin-walled pier; -The standard value of shear force borne by all the steel sections configured at one end of the double-limb thin-walled pier; - The standard value of shear force borne by all steel plates in the double-limb thin-walled pier configuration; -The standard value of the shear force borne by the double-limb thin-walled pier is taken as... ; , - Width and height of thin-walled pier section; - Standard value of tensile strength of structural steel; -The cross-sectional area of ​​the steel section at one end of the double-limb thin-walled pier can be taken as the smaller value of the cross-sectional areas of the steel sections at both ends; -Calculate the shear span ratio of the interface. ,Pick ; - The reinforcement ratio of longitudinal tensile reinforcement and steel plate within the inclined section. ,Pick ; - Cross-sectional area of ​​the tension steel section of the double-limb thin-walled pier; - Cross-sectional area of ​​tensile reinforcement in double-limb thin-walled piers; - Standard value of compressive strength of a concrete cube with a side length of 150mm; - Reinforcement ratio of stirrups in the inclined section of a double-limb thin-walled pier; -Standard value of tensile strength of stirrups in inclined section of double-limb thin-walled pier.

10. The design method for a double-limb steel-concrete thin-walled pier suitable for high-intensity seismic zones according to claim 9, characterized in that, When performing overall stability calculations, the shear section of a double-limb steel-concrete thin-walled pier should conform to the following formula: 。

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