Steel box concrete composite pier column and construction method thereof

Abstract

The present application relates to the technical field of bridge engineering, and provides a steel box concrete composite pier column and a construction method thereof. The steel box concrete composite pier column comprises a steel box and a concrete structure, the steel box further comprises a plurality of grid plates connected to the inner side wall thereof, the grid plates are arranged along the length direction of the steel box, the grid plates are arranged in parallel or orthogonally in the steel box, the grid plates divide the internal space of the steel box into a plurality of sub-chambers, and the concrete structure is cast in the steel box. The steel box concrete composite pier column can solve the problems of reduced bearing capacity and instability caused by weakened constraint effect when the existing steel box concrete structure is applied to a large-size pier column.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and in particular to a steel box concrete composite pier and its construction method. Background Technology

[0002] Compression columns, as a primary load-bearing structure, are widely used in bridge engineering, such as bridge towers of cable-stayed bridges and piers of beam bridges. They have a decisive impact on the safety, durability, and aesthetics of bridges. As bridge construction continues to develop towards higher piers and longer spans, the cross-sectional dimensions and height of bridge piers are also increasing, which places higher demands on the compressive bearing capacity, stability, durability, and seismic performance of bridge piers.

[0003] Existing reinforced concrete piers are heavy, densely reinforced, consume a lot of formwork and supports during construction, and have poor seismic performance. When applied to large-scale scenarios (such as when the minimum dimension of the component cross-section in any direction is greater than or equal to three meters), they are prone to cracking under shrinkage, creep, dead and live loads, and ambient temperature. On the other hand, pure steel structure piers require a large number of stiffening structures to solve the problem of compressive stability of the steel wall panels. This results in complex construction, large steel consumption, and a large amount of anti-corrosion coating work during operation, leading to huge initial construction and maintenance costs.

[0004] Steel-concrete composite structures are composite structures formed by filling concrete into a polygonal steel box. They combine the structural advantages of both steel and concrete, while using less steel than steel piers and columns. They feature high load-bearing capacity, strong resistance to instability, and convenient construction. The steel box acts as a confinement ring for the concrete, increasing its compressive strength; simultaneously, the concrete provides unilateral support to the steel box, reducing the risk of instability. For components with smaller cross-sectional dimensions, the high steel content of steel-concrete composite structures results in strong constraint between the steel box and the concrete, ensuring coordinated stress distribution and allowing them to function as a unified whole.

[0005] However, when applied to large-scale components, the increased size of the steel box, coupled with the economic constraint that the wall thickness cannot be increased proportionally, leads to a decrease in the steel content and an increase in the width-to-thickness ratio of the steel box concrete structure. This weakens the confinement effect of the steel box concrete, potentially causing the steel box and concrete to deform in unison. After pouring excessive amounts of concrete, the steel box experiences non-uniform out-of-plane bulging deformation due to lateral compression from the concrete, easily leading to local instability. In severe cases, if significant slippage or separation occurs between the steel box and the concrete, the concrete becomes an external load on the steel structure, losing its supporting function for the steel box and further reducing the load-bearing capacity of the steel box concrete structure.

[0006] To improve the confinement effect of steel-concrete composite structures, existing technologies often incorporate plate-bed stiffeners (PBLs) at the interface between the steel box and the concrete. This strengthens the out-of-plane stiffness of the steel box, reducing the risk of local instability, and also provides a tight connection between the PBLs and the concrete, minimizing relative slippage and separation between the two. However, large-sized steel-concrete composite piers require numerous longitudinal and transverse PBLs to resist local buckling, resulting in a large steel consumption and extensive welding work. Furthermore, when the stiffeners are insufficient in quantity or stiffness, exhibiting flexible stiffener characteristics, a significant risk of separation between the steel box and the concrete remains. Therefore, there is an urgent need to explore a novel steel-concrete composite structure with good confinement effect, high load-bearing capacity, strong resistance to instability, and low steel consumption to ensure reliable bridge stress and operational safety. Summary of the Invention

[0007] The purpose of this invention is to solve the problem that the existing steel box concrete structure, when applied to large-scale piers, suffers from reduced bearing capacity and is prone to instability due to weakened constraint effect, and to provide a steel box concrete composite pier and its construction method.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A steel-concrete composite pier includes a steel box and a concrete structure. The steel box also includes several grating plates connected to its inner sidewalls. The grating plates are all arranged along the height direction of the steel box. The grating plates are arranged parallel or orthogonally inside the steel box. The grating plates divide the internal space of the steel box into several sub-cavities. The concrete structure is poured inside the steel box.

[0010] The steel box can be made of multiple plates spliced ​​together, or it can be formed by bending a single plate or by forming a single piece; the cross-section of the steel box can be various polygons, such as rectangles, hexagons and octagons.

[0011] The grating can be in various shapes, such as flat or curved plates, as long as they can be arranged parallel or orthogonal to each other and divide the internal space of the steel box into multiple sub-chambers while avoiding dead corners for concrete pouring. For example, several parallel gratings can be directly set, or several perpendicular gratings can be used to divide the internal space of the steel box into several rectangular columnar sub-chambers.

[0012] This scheme involves installing several grating plates of the same height inside the steel box, which divide the internal space of the steel box into several smaller sub-cavities. Since adjacent sub-cavities share grating plates, under the same total steel content, this scheme has a higher steel content in each sub-cavity compared to existing steel box concrete structure schemes. This can effectively constrain the outward expansion deformation of the concrete structure inside the sub-cavities under pressure, so that the concrete structure is under triaxial compression.

[0013] Meanwhile, the internal space of the steel box is divided into several sub-cavities. After the concrete structure is poured, the concrete structures in adjacent sub-cavities constrain each other, further enhancing the confinement effect of the grating plates on the concrete within each sub-cavity. Furthermore, each grating plate is supported on both sides by the concrete structures in the adjacent sub-cavities, significantly enhancing its resistance to local buckling. Simultaneously, multiple grating plates divide the steel box into several sub-cavities with smaller cross-sectional side lengths, thereby reducing the width-to-thickness ratio of each sub-cavity. The grating plates also restrict the out-of-plane deformation of the steel box, significantly enhancing its resistance to local buckling.

[0014] When the grating plates are arranged orthogonally, the included angle between the intersecting grating plates is 90°, which makes it less likely for dead corners to appear in the concrete pouring, thus avoiding the phenomenon of incomplete pouring and voids. Moreover, when the grating plates are arranged orthogonally, the binding force of the concrete is highly effective, and there will be no situation where part of the binding force is converted into tangential friction force as in the case of oblique arrangement, which would reduce the binding effect and affect the strength of the steel box concrete composite pier.

[0015] Meanwhile, the internal space of the steel box is divided into several sub-chambers. After the concrete structure is poured, the adjacent sub-chambers are squeezed and constrained to each other, so that the concrete is in a triaxial compression state. At the same time, each grid plate is supported by the concrete structure in the sub-chambers on both sides, which significantly enhances its resistance to local buckling.

[0016] Furthermore, the connection between the grating and the steel box forms a strong internal lattice-type stiffening system, which increases the torsional stiffness and axial compressive stiffness of the steel box section, effectively improves the load-bearing capacity of the steel box structure, reduces the risk of overall instability, and limits the deformation of the steel box during manufacturing, transportation, installation, concrete pouring, and operation.

[0017] In summary, this scheme can improve the compressive strength of the pier column and reduce the risk of instability by increasing the steel content, reducing the width-to-thickness ratio, and utilizing the mutual constraints between the sub-chambers to effectively enhance the confinement effect of the steel box on the concrete structure.

[0018] Furthermore, this solution can use steel boxes as construction templates for concrete pouring, thereby achieving construction without supports, templates, or vibration, simplifying the construction and installation of bridge piers and reducing construction costs and environmental impact; and the segmented steel boxes, due to their reduced height, are more convenient to manufacture, transport, and hoist.

[0019] Meanwhile, the steel box structure can isolate the internal grating and concrete structure from the influence of the external environment, such as water, air and salt corrosion; and the grating is wrapped by the concrete structure, which further isolates it from the external environment, thus reducing the amount of anti-corrosion coating work and extending the service life of the pier column.

[0020] As a preferred embodiment of the present invention, when the thickness of the grating plate is greater than eight millimeters, the grating plate is a flat plate; the grating plate is provided with through holes; the through holes are used to connect the sub-chambers located on both sides of the grating plate.

[0021] The arrangement of through holes on the grating plate should ensure that there is at least one through hole between two adjacent sub-chambers. Alternatively, the number of through holes can be increased to allow multiple through holes between two adjacent sub-chambers. The cross-section of the through holes can be of various shapes, such as circular or rectangular.

[0022] When the thickness of the grating plate exceeds eight millimeters, using a flat plate ensures sufficient in-plane and out-of-plane stiffness, thereby guaranteeing the restraint effect, ultimate bearing capacity, and buckling resistance of the steel-concrete composite pier column in this design. Furthermore, this design incorporates through-holes in the flat grating plate, allowing the concrete structure to flow freely between the sub-chambers during pouring. This enhances the overall integrity of the concrete structure and creates shear-resistant axes at the through-holes, distributing some of the vertical shear force borne by the grating plate to the concrete structure. This ensures coordinated stress distribution between the grating plate and the concrete structure, preventing relative slippage or separation between the steel box and the concrete structure, thus enhancing structural safety.

[0023] As a preferred embodiment of the present invention, when the thickness of the grating plate is less than or equal to eight millimeters, the grating plate is a corrugated plate; the corrugated surface direction of the corrugated plate is perpendicular to the height direction of the steel box.

[0024] When the thickness of the grating is less than or equal to eight millimeters, in order to ensure that the grating has sufficient in-plane and out-of-plane stiffness, thereby guaranteeing the restraint effect, ultimate bearing capacity and buckling resistance of the steel box concrete composite pier column of this scheme, a corrugated plate grating is used. On the one hand, the out-of-plane stiffness of the corrugated plate is greater than that of the flat plate, and the corrugated plate is arranged along the height direction perpendicular to the steel box, which can obtain greater axial compressive stiffness to improve its ultimate bearing capacity. On the other hand, since the bond between the grating and the concrete structure is strong, no additional structure is needed on the grating to avoid relative slippage or separation between the steel box and the concrete structure.

[0025] As a preferred embodiment of the present invention, it further includes a plurality of inner partitions; the surface of the inner partitions is perpendicular to the height direction of the steel box; each of the inner partitions is spaced apart along the height direction of the steel box; and each inner partition has a through hole at a position corresponding to each of the sub-chambers.

[0026] The inner partition of this design can serve as a rigid transverse stiffener for the steel box wall panel, ensuring that the steel structure of the steel box concrete pier maintains its designed shape during manufacturing, transportation, installation, and concrete pouring, thus avoiding excessive deformation. The through holes set at the corresponding positions of the sub-cavities are to allow the concrete structure to flow freely between the multiple steel box sections during pouring, thereby enhancing the integrity of the steel box concrete composite pier.

[0027] As a preferred embodiment of the present invention, the steel box is divided into multiple segments along its height direction; each segment of the steel box is provided with an inner partition at both ends.

[0028] The connection between the steel box sections should refer to the existing connection methods, such as welding connection and threaded connection.

[0029] This solution facilitates the standardization of steel box structures. For piers of different heights, different numbers of segments can be spliced ​​together. At the same time, smaller segments make the manufacturing and transportation of steel boxes easier. In addition, internal partitions are installed at both ends of each steel box segment to prevent excessive deformation of the steel box during manufacturing, transportation, installation, concrete pouring and other construction processes.

[0030] As a preferred embodiment of the present invention, the height of each section of the steel box is less than or equal to four meters.

[0031] The steel box in this design facilitates the operation of existing conventional transportation and hoisting equipment.

[0032] As a preferred embodiment of the present invention, the minimum width of the sub-chamber cross-section is d; the maximum width of the sub-chamber cross-section is D; d≥0.3m∩D≤0.8m.

[0033] This solution can prevent poor flow between the sub-chambers during concrete pouring.

[0034] As a preferred embodiment of the present invention, the steel box has a rectangular cross-section; stiffening ribs are provided at the four corners of the steel box; the stiffening ribs are connected to the inner surfaces of the two side walls with the larger width of the steel box; the stiffening ribs are provided along the entire length of the steel box in the height direction.

[0035] Stiffening ribs can be installed on both sides of the corner area, or they can be installed only on one side of the weakly constrained area, depending on the cross-sectional shape and stress analysis of the pier. For example, for a rectangular cross-section pier, stiffening ribs can be installed only on the two ends of the long side of the steel box near the corner.

[0036] This solution can further prevent the concrete structure from separating from the steel box and avoid the resulting local outward bending deformation.

[0037] A construction method for a steel-concrete composite pier includes the following steps:

[0038] A. Fabricate a steel box according to the required height;

[0039] B. Install the steel box at the predetermined position on the pier; if there are multiple sections of the steel box, splice the sections of the steel box together to achieve the required height;

[0040] C. Concrete structures are poured into each sub-chamber of the steel box; the concrete structures are poured in a clockwise or counterclockwise direction from the sub-chambers near the side wall of the steel box to the sub-chambers near the center of the steel box; the construction of the steel box concrete composite pier is completed.

[0041] If there are columns inside the steel box and a concrete structure needs to be poured, the pouring of the concrete structure in the columns can be arranged freely, such as before pouring all the sub-chambers or after pouring all the sub-chambers.

[0042] The construction method of this plan can flexibly arrange the number of steel boxes according to the transportation conditions and hoisting capacity of the specific construction site, thereby facilitating the transportation and hoisting of the steel boxes. For example, when waterway transportation is used, the steel boxes can be manufactured and transported in their entirety in the factory, and then hoisted as a whole at the bridge site. If transportation conditions are limited in mountainous areas, the steel boxes can be divided into multiple sections for transportation, and then reassembled at the bridge site before hoisting.

[0043] Furthermore, during pouring, the steel box, as the main load-bearing component of the steel box concrete composite pier, has high strength. Therefore, the sub-cavities close to the side walls of the steel box have higher strength than the sub-cavities located in the center of the steel box. In this scheme, the concrete structure is poured starting from the stronger sub-cavities near the side walls of the steel box, resulting in smaller deformation of the first poured sections. When pouring reaches the sub-cavities near the center of the steel box, the first poured sub-cavities can provide additional support for the weaker central sub-cavities, thus further reducing the deformation of the steel box concrete composite pier poured according to this scheme.

[0044] As a preferred embodiment of the present invention, when the cross-section of the steel box is rectangular, the pouring of the concrete structure begins from the sub-chamber that is attached to the side wall of the steel box with the smaller width.

[0045] When the cross-section of the steel box is an unequal-sided rectangle, the sub-cavities that are close to the narrower sidewalls have a stronger restraining effect; when the sub-cavities that are close to the narrower sidewalls are poured first, the deformation of the first poured part is smaller; when the pouring reaches the sub-cavities that are close to the wider sidewalls, the first poured sub-cavities can provide additional support for them, thus making the deformation of the steel box concrete composite pier column poured according to this scheme smaller.

[0046] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0047] 1. This invention uses grating plates to divide a large-scale, low-steel-content steel box into multiple smaller sub-cavities with moderate steel content. This effectively enhances the confinement effect of the steel box on the concrete structure within each sub-cavity, improving the compressive strength of the concrete. Furthermore, the concrete structure within the box supports the steel box on one side and the grating plates on both sides, delaying the local buckling of the steel structures. Simultaneously, the grating plates and internal partitions act as internal stiffeners for the steel box, effectively increasing its torsional stiffness and limiting outward bulging deformation during manufacturing, transportation, installation, concrete pouring, and bridge operation.

[0048] 2. The steel box concrete composite pier of the present invention relies on the grating plate and the steel box to form a strong lattice-type skeleton structure, which improves the axial compressive stiffness and bearing capacity of the steel box section. Under the same steel content of the section, the steel box concrete composite pier of the present invention has a higher bearing capacity than the reinforced concrete pier and is comparable to the traditional PBL stiffened steel box concrete pier, but has better ductility, which can improve the seismic performance of high piers and long-span bridge piers.

[0049] 3. The present invention can prefabricate steel boxes in sections to adapt to different construction environments and meet the needs of different transportation and hoisting capabilities, resulting in efficient construction and facilitating industrialized and prefabricated construction. When pouring concrete structures, the steel boxes and grating plates also serve as construction templates for the concrete structures, thereby achieving construction without supports, templates, or vibration, simplifying construction and installation operations, and minimizing environmental impact.

[0050] 4. This invention fills the inside of the steel box with a concrete structure, so that the structures inside the steel box, such as the grating, are wrapped by the concrete, which improves the corrosion resistance of the internal structure. Therefore, the painting work during the operation period is less than that of pure steel structure piers. At the same time, the steel box completely blocks the entry of water, air, salt and other media from the external environment, reducing the corrosion of the grating and the deterioration of the concrete structure, and enhancing the service life.

[0051] 5. The steel box concrete composite pier of the present invention, under the premise of ensuring sufficient bearing capacity and stiffness, uses an internal grating plate to replace a large amount of steel mesh in the reinforced concrete pier, saving the labor-intensive steel reinforcement binding work, and making construction convenient and efficient; compared with the large number of stiffening ribs and complex structure of the PBL stiffened steel box concrete pier, the steel box concrete composite pier of the present invention only needs to set a small number of stiffening ribs in areas with weaker restraint effects, such as the two ends of the corner of the side wall of the rectangular steel box with a larger width, with less steel consumption, simple structure and less welding work.

[0052] 6. The grating plate installed in the steel box in this invention can serve as an internal stiffening rib of the steel box, limiting the deformation of the steel box during manufacturing, transportation, installation, concrete pouring and operation.

[0053] 7. The present invention has a wide range of applications and has the potential for widespread application. It is not only applicable to bridge towers of cable-stayed bridges and piers of beam bridges, but also to compression arch structures, load-bearing columns and load-bearing walls in the building field. Attached Figure Description

[0054] Figure 1 This is a three-dimensional structural diagram of the steel box-concrete composite pier column in Example 1, showing the hidden steel box structure behind it.

[0055] Figure 2 This is a cross-sectional schematic diagram of a steel-concrete composite pier column according to Example 1;

[0056] Figure 3 This is a schematic cross-sectional view of the inner diaphragm of a steel-concrete composite pier column according to Example 1.

[0057] Figure 4 This is a three-dimensional structural diagram of the steel box behind the steel box of a steel box concrete composite pier column in Example 2;

[0058] Figure 5 This is a cross-sectional schematic diagram of a steel-concrete composite pier column according to Example 2;

[0059] Figure 6 This is a schematic cross-sectional view of the inner diaphragm of a steel-concrete composite pier column according to Example 2.

[0060] Figure 7 This is a schematic diagram comparing the finite element simulation results of the steel-concrete composite pier column of the present invention and the prior art.

[0061] Figure 8 This is a schematic diagram of the stress distribution of the steel-concrete composite pier column under ultimate load in Example 1;

[0062] Figure 9 This is a schematic diagram of the stress distribution of the steel-concrete composite pier column under ultimate load in Example 2;

[0063] Icons: 1-Steel box; 2-Concrete structure; 3-Column;

[0064] 11-Grating plate; 12-Strengthening rib; 13-Inner partition. Detailed Implementation

[0065] The present invention will now be described in detail with reference to the accompanying drawings.

[0066] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0067] Example 1

[0068] like Figures 1-3 As shown, the steel-concrete composite pier column used in this invention comprises a steel box 1 and a concrete structure 2. The steel box 1 is divided into several segments along its height, and the segments are welded together. The interior of the steel box 1 is provided with several vertically oriented grating plates 11 at the same height as the steel box 1. At the segmentation locations of the steel box 1, there are horizontally oriented inner partitions 13. The grating plates 11 and the inner partitions 13 together divide the interior of the steel box 1 into several smaller sub-cavities, and the concrete structure 2 is poured into these sub-cavities.

[0069] In this embodiment, the steel box 1 has a rectangular cross-section of 2000mm × 1550mm, and is composed of four 12mm thick side plates spliced ​​together, thus satisfying the preferred width-to-thickness ratio of the side plates of the steel box 1:

[0070]

[0071] In the formula, B1 is the width of the side plate, t1 is the thickness of the side plate, and f y The yield strength of the material used for the side plate.

[0072] Considering the difficulty of transportation, the height of each section of steel box 1 is controlled within 4000mm.

[0073] The grating plate 11 is an 8.5mm thick flat plate, and all of them are vertically connected to the inner wall of the steel box 1. The grating plates 11 are also arranged perpendicularly to each other, so that all the sub-chambers are rectangular to prevent the generation of dead corners in concrete pouring. In order to ensure that the flow of concrete structure 2 is unobstructed during pouring, the cross-sectional dimensions of the sub-chambers in this embodiment are controlled at 500mm×516mm. The grating plates 11 are welded to the inner wall of the steel box 1 and to each other.

[0074] The steel box 1 is also provided with stiffening ribs 12 at its four corners, with two stiffening ribs 12 at each corner. Each stiffening rib 12 is connected to the inner wall of the two wider side plates of the steel box 1 and extends continuously along the height of the side plates. In this embodiment, the stiffening ribs 12 are 8mm thick and 100mm wide to meet the preferred width-to-thickness ratio of the stiffening ribs 12.

[0075]

[0076] In the formula, B2 is the width of stiffening rib 12, t2 is the thickness of stiffening rib 12, and f y The yield strength of the material used for stiffening rib 12.

[0077] The stiffening rib 12 is also provided with circular through holes on its surface to connect more firmly to the concrete structure 2; the diameter of the circular through holes should be determined according to the size of the grating plate 11, preferably 50mm to 70mm, and the center distance between two adjacent circular through holes can preferably be 200mm to 400mm.

[0078] Through holes are provided on each grid plate 11 at the position corresponding to the side wall of each sub-chamber, and on each inner partition plate 13 at the position corresponding to the bottom or top surface of each sub-chamber, so that each sub-chamber can be connected to each other, so that the concrete structure 2 cast in each sub-chamber can be connected into a whole; the thickness of the inner partition plate 13 can be selected as 0.8 to 1.0 times the thickness of the grid plate 11.

[0079] When the steel components are all made of Q335C steel, the concrete structure is made of C40 self-compacting concrete, the reinforcing steel is made of HRB400 steel, and the steel content is kept constant, and the load is an axial compressive load, finite element simulation can yield the following results: Figure 7 and Figure 8 The results shown; Figure 7 In the diagram, curve B represents the calculation result of the steel box concrete composite pier in this embodiment, curve C represents the calculation result of the existing PBL stiffened steel box 1 concrete pier, and curve D represents the calculation result of the reinforced concrete pier.

[0080] The results show that the bearing capacity of the steel box concrete composite pier in this embodiment is 20% higher than that of the reinforced concrete pier; it is comparable to the bearing capacity of the existing PBL stiffened steel box concrete pier, but has better ductility, thus having better seismic performance.

[0081] It should be noted that the shape, size and position of the steel box 1, grating plate 11 and stiffening rib 12 used in this embodiment are only one specific solution and will vary with the specific requirements of the project. For example, the steel box 1 may also be hexagonal, and the number of stiffening ribs 12 may increase or decrease.

[0082] Example 2

[0083] like Figures 4-6 As shown, based on Example 1, the grating plate 11 is replaced with a corrugated plate material, and vertical columns 3 are installed at the intersection of each grating plate 11 to prevent the generation of dead corners in concrete pouring.

[0084] In this embodiment, the grating plate 11 is a corrugated plate with a thickness of 5mm; since the included angle of the intersecting grating plates 11 is 90°, a column 3 with a rectangular cross-section is adopted, and the length × width × column thickness is 100mm × 100mm × 10mm. During installation, a notch corresponding to the size of the column 3 is cut at the intersection of the grating plates 11, and the side wall of the column 3 is welded to the grating plate 11.

[0085] By performing finite element simulation on the steel-concrete composite pier in this embodiment under the same conditions as in Embodiment 1, the following results can be obtained: Figure 7 and Figure 9 The calculation results are shown below; Figure 7 In the diagram, curve A represents the calculation result of the steel box concrete composite pier in this embodiment, curve C represents the calculation result of the existing PBL stiffened steel box 1 concrete pier, and curve D represents the calculation result of the reinforced concrete pier.

[0086] The results show that the bearing capacity of the steel box concrete composite pier in this embodiment is 25% higher than that of the reinforced concrete pier; it is comparable to the bearing capacity of the existing PBL stiffened steel box concrete pier, but has better ductility, thus having better seismic performance.

[0087] It should be noted that the column 3 used in this embodiment corresponds to the grid plate 11 that is arranged perpendicularly to each other in this embodiment. If the arrangement of the grid plate 11 is different, other shapes of column 3, such as hexagonal columns, can also be used.

[0088] Example 3

[0089] like Figures 1-6 As shown, the steel-concrete composite pier column used in this invention, applied to any of the steel-concrete composite pier columns in Examples 1 and 2, includes the following steps:

[0090] S1. Fabricate several steel boxes 1 according to the required height and transport each section of steel box 1 to the construction site;

[0091] During manufacturing, the steel box 1 is divided into several side plates with the same number of sides as the cross section according to its shape. The side plates are then assembled into the steel box 1 by welding. Subsequently, the grating plate 11 is welded into the steel box 1.

[0092] For orthogonally arranged grating 11, if the grating 11 is flat, the boundary lines of the intersecting grating 11 are first welded to form the skeleton of the orthogonally arranged grating 11. Then the entire skeleton of the grating 11 is placed inside the steel box 1. After the position is accurately determined, the boundary line between the grating 11 and the inner wall of the steel box 1 is welded.

[0093] For orthogonally arranged grating 11, if the grating 11 is a corrugated plate, due to the complex shape of the corrugated plate, dead corners for concrete pouring are easily generated at the connection points of the corrugated plates. Therefore, in this embodiment, a column 3 with a rectangular cross section is set at the intersection of each corrugated plate, and the corrugated plate at the intersection is welded to the outer wall of the column 3 to form the skeleton of the orthogonally arranged grating 11. The thickness of the column 3 should be 1.2 to 1.6 times the thickness of the corrugated plate to meet the welding specifications. Then, the entire skeleton of the grating 11 is placed inside the steel box 1. After the position is accurately determined, the boundary line between the grating 11 and the inner wall of the steel box 1 is welded.

[0094] For parallel-arranged grating plates 11, the boundary line between the grating plate 11 and the inner wall of the steel box 1 can be directly welded.

[0095] If the steel box concrete composite pier also includes stiffening ribs 12, they are welded to the two ends of the wider side plate near the corner in this step.

[0096] If the steel-concrete composite pier also includes an inner diaphragm 13, it is welded to both ends of the steel box 1 in this step. The shape of the inner diaphragm 13 should avoid interference with other structures inside the steel box 1. If the steel-concrete composite pier also includes a column 3, the inner diaphragm 13 can be cut at the corresponding position of the column 3. Or, if the steel-concrete composite pier also includes stiffening ribs 12, the inner diaphragm 13 can have a strip opening at the corresponding position of the stiffening ribs 12. The inner diaphragm 13 can be welded to a position closer to the interior of the steel box 1 than the end face of the steel box 1 to facilitate welding operations during the assembly of each section of the steel box 1.

[0097] S2. Transport the steel box 1 to the bridge site and install the steel box 1 at the predetermined position on the pier. If there are multiple steel box 1 sections, the subsequent steel box 1 sections are spliced ​​to the upper end of the previous steel box 1 section in sequence. During the assembly, the side plates and grating plates 11 of the two adjacent steel box sections are welded together. If the steel box 1 is also equipped with stiffening ribs 12, the stiffening ribs 12 of the two adjacent steel box sections are also welded together.

[0098] S3. From the through hole of the inner partition 13 at the top of the uppermost steel box 1, pour concrete structure 2 into each sub-chamber of the steel box 1; pour in a clockwise or counterclockwise direction from the outside of the steel box 1 to the center of the steel box 1 until all sub-chambers are poured; if the cross-sectional shape of the steel box 1 is an unequal rectangle, start pouring from the sub-chamber that is close to the side plate with the smaller width of the steel box 1; complete the construction of the steel box concrete composite pier column.

[0099] For example, for Figure 2 Since sub-chambers I, II, and III have the side plates containing the short side of the rectangular steel box as their side walls, they can be poured in the order of I, II, III, IV, V, VI, VII, VIII, IX, X, XI, and XII.

[0100] When connecting the steel-concrete composite pier column of this embodiment to the bridge, the following steps can be referred to:

[0101] S1. Connect steel box 1 to the bridge foundation;

[0102] The bottom of the steel box 1 is inserted into the bridge foundation to a certain depth. If it is a steel box concrete composite pier column containing multiple steel box 1 sections, the bottom of the bottommost steel box 1 is inserted into the bridge foundation to a certain depth. The main reinforcement and steel mesh inside the foundation are inserted into the interior of the steel box 1, and concrete is poured between the bottom of the steel box 1 and the bridge foundation to achieve the anchorage connection between the steel box 1 and the foundation.

[0103] S2. Connect steel box 1 to the bridge cap beam;

[0104] For steel cap beams, several perforated steel plates can be welded to the corresponding positions of the top of the steel cap beam and the top of the steel box 1 and extended into the steel box 1 to a certain anchorage depth. If it is a steel box concrete composite pier column containing multiple steel box 1 sections, the perforated steel plates are extended into the interior of the topmost steel box 1. The contact line between the top surface of the steel box 1 and the bottom surface of the cap beam is welded. After the concrete structure 2 is poured in the steel box 1, the connection between the steel box concrete composite pier column and the steel cap beam can be realized.

[0105] For concrete cap beams, several perforated steel plates and closed steel plates with a height of 0.5m to 1.0m and a shape slightly larger than steel box 1 can be pre-embedded in the bottom area of ​​the cap beam. Each closed steel plate forms a polygon corresponding to the cross-sectional shape of steel box 1, so that steel box 1 can be fitted into the closed steel plate. The perforated steel plates are inserted into the interior of steel box 1, and the contact line between the closed steel plate and steel box 1 is welded around them. When the concrete structure 2 is poured in steel box 1, the connection between the steel box concrete composite pier and the concrete cap beam can be realized.

[0106] The construction method provided in this embodiment simplifies the manufacturing and on-site installation processes, improving the industrialization and assembly level of bridge piers. The steel box 1 can be flexibly divided into multiple sections according to transportation conditions and hoisting capacity. For example, when using waterway transportation, the steel box 1 can be manufactured and transported in its entirety at the factory, and then hoisted as a whole at the bridge site. In mountainous areas where transportation is limited, the steel box 1 can be divided into multiple sections for transportation, then reassembled on-site before hoisting. The pouring process of the concrete structure 2 relies on the steel box 1 itself as a formwork for pouring the concrete structure 2, achieving concrete construction without supports, formwork, or vibration. Furthermore, this embodiment provides a connection method between the steel box concrete composite pier and the bridge foundation and cap beam, which has good adaptability and feasibility.

[0107] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A steel-concrete composite pier, comprising a steel box (1) and a concrete structure (2), characterized in that, The steel box (1) also includes a number of grating plates (11) connected to its inner sidewalls; the grating plates (11) are all arranged along the height direction of the steel box (1); the grating plates (11) are arranged parallel or orthogonally inside the steel box (1); the grating plates (11) divide the internal space of the steel box (1) into a number of sub-chambers; the steel box (1) is filled with the concrete structure (2). The grating plate (11) is a corrugated plate; the corrugated plate has a corrugated surface direction perpendicular to the height direction of the steel box (1), and a column (3) is installed at the intersection of each grating plate (11) along the vertical direction, and the cross-sectional shape of the column (3) is rectangular; The steel box (1) has a rectangular cross section; stiffening ribs (12) are provided at the four corners of the steel box (1); the stiffening ribs (12) are connected to the inner surfaces of the two side walls with larger widths of the steel box (1); the stiffening ribs (12) are provided along the height direction of the steel box (1).

2. The steel-concrete composite pier according to claim 1, characterized in that, It also includes several inner partitions (13); the surface of the inner partitions (13) is perpendicular to the height direction of the steel box (1); each inner partition (13) is spaced apart along the height direction of the steel box (1); the inner partitions (13) have through holes at the corresponding positions of each sub-chamber.

3. A steel-concrete composite pier according to claim 2, characterized in that, The steel box (1) is divided into multiple sections along its height direction; each section of the steel box (1) is provided with an inner partition (13) at both ends.

4. A steel-concrete composite pier according to claim 3, characterized in that, The height of each steel box (1) is less than or equal to four meters.

5. A steel-concrete composite pier according to any one of claims 1 to 4, characterized in that, The minimum width of the sub-chamber cross-section is d; the maximum width of the sub-chamber cross-section is D; d≥0.3m∩D≤0.8m.

6. A construction method for a steel-concrete composite pier, applied to a steel-concrete composite pier as described in any one of claims 1 to 5, characterized in that, Includes the following steps: The steel box is manufactured according to the required height (1); Install the steel box (1) at the predetermined position of the pier column; if there are multiple sections of the steel box (1), splice the sections of the steel box (1) together to achieve the required height; Concrete structures (2) are poured into each sub-chamber of the steel box (1); the concrete structures (2) are poured in a clockwise or counterclockwise direction from the sub-chamber near the side wall of the steel box (1) to the sub-chamber near the center of the steel box (1); the construction of the steel box concrete composite pier is completed.

7. The construction method of a steel-concrete composite pier according to claim 6, characterized in that, When the cross-section of the steel box (1) is rectangular, the pouring of the concrete structure (2) begins from the sub-chamber that is close to the side wall of the steel box (1) with a smaller width.

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