Steel-ultra high performance concrete composite bridge and shear-resistant connecting structure thereof

Abstract

The application provides a shear-resistant connecting structure of a steel-ultra-high-performance concrete combined bridge, which comprises a profile steel component, an ultra-high-performance concrete component and a shear key for connecting the profile steel component and the ultra-high-performance concrete component; the shear key is arranged in a single row or multiple rows, each row of the shear key is sequentially connected by a plurality of shear key units along the longitudinal direction of the profile steel component, the shear key unit comprises a corrugated steel plate and a vertical component formed on the corrugated steel plate, the corrugated steel plate is fixedly connected with the profile steel component, and a longitudinal resistance cavity is formed between the shear key unit and the profile steel component and between two adjacent shear key units; when the ultra-high-performance concrete component is connected with the profile steel component, the ultra-high-performance concrete fills the longitudinal resistance cavity, and a mortise and tenon structure is formed. The shear-resistant connecting structure of the steel-ultra-high-performance concrete combined bridge can effectively connect the steel structure and the ultra-high-performance concrete structure, improve the shear-resistant bearing capacity, and facilitate the arrangement of steel bars.

Description

Technical Field

[0001] This invention relates to the field of civil engineering technology, specifically to a steel-ultra-high performance concrete composite bridge and its shear-resistant connection structure. Background Technology

[0002] Bridge development has progressed to encompass various types, including concrete bridges, steel bridges, and steel-concrete composite bridges. Ultra-high performance concrete (UHVPC) is a new type of composite cement-based material with a compressive strength exceeding 120 MPa and a tensile strength exceeding 7 MPa. The advent of UHVPC has driven innovation in bridge structures, particularly in its application in steel-concrete composite bridges, which has solved many problems caused by the insufficient tensile strength of traditional concrete.

[0003] The weakest link in the design of steel-concrete composite bridges is the interface between the two materials. The bond between steel and concrete at this interface is very weak, making it highly susceptible to bond failure. Effectively connecting steel and ultra-high performance concrete is a key technical challenge. Because shear slippage can occur at the interface under vehicle loads, shear-resistant connection members become a crucial component of steel-concrete composite structures. The design of these shear-resistant connection members must effectively prevent horizontal slippage and separation at the steel-concrete interface, ensuring that the steel and concrete structures, with their significantly different moduli of elasticity, work together to safely transfer vehicle loads to the bridge piers.

[0004] The primary function of shear connectors is to resist horizontal shear forces and vertical uplift forces. Currently, common shear connection structures often employ studs and perforated steel plates welded to the steel structure. While these two construction techniques are mature, they still have shortcomings from a stress perspective. For example, the effective bearing surface of studs is only at the root region, and the effective bearing surface of perforated steel plates is the perforated area; both have relatively small cross-sectional areas, resulting in low shear capacity. Increasing the number of studs and perforated steel plates is necessary to improve the structural bearing capacity. Furthermore, another important issue that shear connection structures need to address is the reinforcement arrangement in the concrete structure. Dense studs and perforated steel plates will hinder reinforcement placement, increasing construction difficulty.

[0005] Therefore, there is an urgent need for a new shear-resistant connection structure to solve the above-mentioned technical problems. Summary of the Invention

[0006] The first aspect of the present invention is to provide a shear connection structure for a steel-ultra-high performance concrete composite bridge, which overcomes the problems of small bearing surface and low shear bearing capacity of existing connectors, effectively connects steel structure and ultra-high performance concrete structure, improves shear bearing capacity, and facilitates the arrangement of reinforcing bars.

[0007] The technical solution of the present invention is as follows:

[0008] A shear connection structure for a steel-ultra-high performance concrete composite bridge includes steel profiles, ultra-high performance concrete components, and shear keys for connecting the steel profiles and ultra-high performance concrete components. The shear keys are arranged in a single row or multiple rows, and each row of shear keys is formed by connecting multiple shear key units sequentially along the longitudinal direction of the steel profiles. Each shear key unit includes a corrugated steel plate and a vertical member formed on the corrugated steel plate. The corrugated steel plate is fixedly connected to the steel profiles, and a longitudinal resistance chamber is formed between the shear key unit and the steel profiles, as well as between two adjacent shear key units.

[0009] When the ultra-high performance concrete component is connected to the steel component, the ultra-high performance concrete fills the longitudinal resistance cavity to form a mortise and tenon structure.

[0010] Furthermore, the shear key has a trapezoidal wave shape.

[0011] Furthermore, the corrugated steel plate includes a first inclined plate, a first horizontal plate connected to the first inclined plate, a second inclined plate connected to the other end of the first horizontal plate, and a second horizontal plate connected to the second inclined plate. The second horizontal plate of the preceding shear key unit is connected to the first inclined plate of the following shear key unit, and the second horizontal plate is fixedly connected to the steel component.

[0012] Furthermore, the angles between the first inclined plate and the first horizontal plate, the angles between the first horizontal plate and the second inclined plate, and the angles between the second inclined plate and the second horizontal plate are all 30-150°.

[0013] Furthermore, the difference between the width of the steel component and the width of the shear key is greater than three times the fiber length, and the fiber is the fiber contained in ultra-high performance concrete.

[0014] Furthermore, the shear keys are a double-row structure, and the spacing between two adjacent rows of shear keys is greater than or equal to 1.5 times the fiber length.

[0015] Furthermore, the vertical member includes a vertical connector formed on the first horizontal plate and the second horizontal plate, a positioning groove formed on the vertical connector, and a stirrup provided in the positioning groove.

[0016] Furthermore, the vertical connecting members are symmetrically distributed on both sides of the longitudinal center line of the first horizontal plate / second horizontal plate, and are obtained by cutting the first horizontal plate / second horizontal plate and bending it by 90°, with the cutting line parallel to the transverse center line of the first horizontal plate / second horizontal plate.

[0017] Furthermore, the opening of the positioning groove is groove-shaped, semi-circular, or V-shaped, and the stirrup is positioned within the positioning groove.

[0018] A second aspect of the present invention is to provide a steel-ultra-high performance concrete composite bridge, including the shear connection structure described in the first aspect.

[0019] Compared with the prior art, the steel-ultra-high performance concrete composite bridge and its shear connection structure provided by the present invention have the following advantages:

[0020] I. The shear connection structure of the steel-ultra-high performance concrete composite bridge provided by this invention comprises shear keys formed by sequentially connecting multiple shear key units along the longitudinal direction of the steel member. Each shear key unit includes a corrugated steel plate and a vertical member. A longitudinal resistance chamber is formed between the shear key unit and the steel member, as well as between adjacent shear keys. When the ultra-high performance concrete member is connected to the steel member, the ultra-high performance concrete fills the longitudinal resistance chamber, forming a tenon-and-mortise structure, providing shear resistance in the longitudinal direction. This effectively weakens the shear force that causes interface slippage. Furthermore, due to the large bearing area of ​​the longitudinal resistance chamber, it provides higher shear bearing capacity. Simultaneously, the longitudinal resistance chamber and the vertical member provide dual pull-out resistance in the height direction. Therefore, the shear connection structure of the steel-ultra-high performance concrete composite bridge provided by this invention overcomes the problems of small bearing surface and inefficient shear bearing capacity of existing connectors, effectively connecting the steel structure and the ultra-high performance concrete structure, and improving the shear bearing capacity.

[0021] II. The shear connection structure of the steel-ultra-high performance concrete composite bridge provided by the present invention involves welding and fixing the second horizontal plate of the shear key to the steel component, then positioning the stirrups in the positioning groove, erecting the formwork, and pouring ultra-high performance concrete to achieve the connection between ultra-high performance concrete and steel component. This method has high construction efficiency and the stirrups are easy to arrange and simple to operate. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural schematic diagram of the shear connection structure of the steel-ultra-high performance concrete composite bridge of the present invention;

[0024] Figure 2 for Figure 1 A schematic diagram of the connection between the steel member and the shear key in the shear connection structure;

[0025] Figure 3 for Figure 2 Partial structural diagram;

[0026] Figure 4 for Figure 2 A schematic diagram of the shear key unit structure. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, and to make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described below.

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] Please refer to the following: Figures 1 to 4 ,in Figure 1 This is a structural schematic diagram of the shear connection structure of the steel-ultra-high performance concrete composite bridge of the present invention; Figure 2 for Figure 1 A schematic diagram of the connection between the steel member and the shear key in the shear connection structure; Figure 3 for Figure 2 Partial structural diagram; Figure 4 for Figure 2 A schematic diagram of the shear key unit structure is shown. The shear connection structure of the steel-ultra-high performance concrete composite bridge of the present invention includes a steel section member 1, an ultra-high performance concrete member 2, and a shear key 3 for connecting the steel section member 1 and the ultra-high performance concrete member 2. The steel section member 1 is an H-shaped hot-rolled steel section, which has the advantages of less welding work and low residual stress. The shear key 3 is fixed to the top surface of the steel section member 1.

[0030] In this invention, the shear keys 3 are arranged in a single row or multiple rows, with each row of shear keys formed by sequentially connecting multiple shear key units 31 along the longitudinal direction of the steel member. Each shear key unit 31 includes a corrugated steel plate 311 and a vertical member 312 formed on the corrugated steel plate. The corrugated steel plate 311 is fixedly connected to the steel member 1, and a longitudinal resistance chamber 32 is formed between the shear key unit 31 and the steel member 1, as well as between two adjacent shear key units 31. Preferably, the shear keys 3 are symmetrically distributed along the longitudinal centerline of the steel member and are in a trapezoidal wave shape.

[0031] In this embodiment, the shear keys 3 are arranged in a single row. The corrugated steel plate 311 includes a first inclined plate 3111, a first horizontal plate 3112 connected to the first inclined plate 3111, a second inclined plate 3113 connected to the other end of the first horizontal plate, and a second horizontal plate 3114 connected to the second inclined plate. The second horizontal plate 3114 of the previous shear key unit is connected to the first inclined plate 3111 of the next shear key unit. The shear key unit is fixedly connected to the steel component 1 through the second horizontal plate 3114, such as by welding. In specific applications, the first inclined plate, the first horizontal plate, the second inclined plate, and the second horizontal plate are steel plates formed by bending, that is, the shear key unit is an integrally formed structure; alternatively, the first inclined plate, the first horizontal plate, the second inclined plate, and the second horizontal plate can be welded and fixed in sequence.

[0032] In this embodiment, the longitudinal resistance chamber formed by the first inclined plate, the first horizontal plate, the second inclined plate, the second horizontal plate, and the steel member 1 is trapezoidal, and the included angles between the first inclined plate 3111 and the first horizontal plate 3112, the first horizontal plate 3112 and the second inclined plate 3113, and the second inclined plate 3113 and the second horizontal plate 3114 are all 30-150°. Preferably, the included angle between the first inclined plate 3111 and the top surface of the steel member is greater than or equal to 45°, and correspondingly, the included angle between the first inclined plate 3111 and the first horizontal plate 3112 is less than or equal to 135°, which is beneficial to the flow and arrangement of fibers in ultra-high performance concrete and can improve the pull-out resistance of the shear connection structure. In addition, the included angle between the first inclined plate and the top surface of the steel member can also be an obtuse angle (less than or equal to 135°), and correspondingly, the included angle between the first inclined plate and the first horizontal plate can be an acute angle (greater than or equal to 45°), which can also improve the pull-out resistance of the shear connection structure.

[0033] The steel plates used in shear key unit 31 are 0.5-1cm thick, and each plate is 5-15cm long. Their width is adjusted according to the width of the steel structural member, ensuring that the difference between the width of the steel structural member and the width of the shear key is greater than three times the fiber length. The fibers are those contained in ultra-high performance concrete, guaranteeing at least 1.5 times the fiber length of space on both sides of the shear key to facilitate fiber flow and distribution during casting. When the shear key 3 is designed in multiple rows, the difference between the width of the steel structural member and the total width of the shear key is greater than three times the fiber length, and the spacing between adjacent rows of shear keys is greater than or equal to 1.5 times the fiber length.

[0034] In addition to the above embodiments, the shear key 3 can also be other shapes, such as an arc-shaped wave. Correspondingly, the vertical member is disposed at the crest of the shear key 3.

[0035] The vertical member 312 provides pull-out resistance and includes a vertical connector 3121 formed on the first horizontal plate 3112 and the second horizontal plate 3114, a positioning groove 3122 formed on the vertical connector, and a stirrup 3123 provided in the positioning groove. The vertical connectors 3121 are symmetrically distributed on both sides of the longitudinal centerline of the first horizontal plate / second horizontal plate, and are obtained by cutting the first horizontal plate / second horizontal plate and then bending it 90°. Preferably, the cutting line is parallel to the transverse centerline of the first horizontal plate / second horizontal plate and symmetrically distributed on both sides of the transverse centerline of the first horizontal plate / second horizontal plate. That is, at least two vertical connectors are provided on each of the first horizontal plate / second horizontal plate. The width of the vertical connector 3121 is 3-6 cm, and the height is 4-6 cm.

[0036] The positioning groove 3122 is used for positioning stirrups. The shape of the groove can be groove-shaped, semi-circular, or V-shaped, and the opening depth is 1-1.5cm. During construction, one end of the stirrup is inserted into the corresponding positioning groove 3122.

[0037] The shear connection structure of the steel-ultra-high performance concrete composite bridge of the present invention is constructed using the following method:

[0038] (1) Design the shear key dimensions, including the width of the shear key steel plate, the bending angle, and the length of each plate in the shear key unit, so that the width of the shear key steel plate meets the requirements of shear bearing capacity verification and normal fiber flow in ultra-high performance concrete.

[0039] (2) Fabricate shear key units according to design requirements. The second horizontal plate of the previous shear key unit is welded and fixed to the first inclined plate of the next shear key unit. Then, the second horizontal plate of each shear key unit is welded and fixed to the top surface of the steel component to realize the installation and fixing of the corrugated steel plate. Then, the stirrups are positioned in the positioning groove of the vertical connector.

[0040] (3) Erect formwork and pour ultra-high performance concrete to form ultra-high performance concrete components, thereby achieving the connection between ultra-high performance concrete components and steel components. During the pouring of ultra-high performance concrete, the ultra-high performance concrete fills the longitudinal cavity formed by the shear keys, enabling the ultra-high performance concrete components to form a tenon and mortise structure. This not only provides shear resistance in the longitudinal direction, effectively weakening the shear force that causes interface slippage, but also provides higher shear bearing capacity.

[0041] The shear connection structure of the steel-ultra-high performance concrete composite bridge of the present invention will be described in detail below through specific embodiments.

[0042] In the shear key unit, the angles between the first inclined plate and the first horizontal plate, the first horizontal plate and the second inclined plate, and the second inclined plate and the second horizontal plate of the corrugated steel plate are all 120°. The thickness of the corrugated steel plate is 1cm, and the length of each plate is designed to be 10cm. The vertical connector is 5cm high and 3cm wide, with a 1cm deep groove opening. The construction method is as follows:

[0043] The components of the composite beam are prefabricated in the prefabrication plant. During the prefabrication of the shear key unit, a straight steel plate is bent three times at 120° to form a corrugated steel plate structure. Then, a 5cm long and 3cm wide steel plate is cut from the horizontal plate along its transverse centerline. This plate is then bent 90° to obtain a vertical connector. A 1cm deep and 1cm long slot is cut at the top of the vertical connector along its transverse centerline. The shear key unit is then welded to the top plate of the steel structure via a second horizontal plate. The front and rear shear key units are butt-welded together via a first inclined plate and a second horizontal plate, ultimately forming shear keys distributed longitudinally along the steel structure. Finally, longitudinal reinforcement is laid, stirrups are arranged, and ultra-high performance concrete is poured to obtain the steel-ultra-high performance concrete composite bridge. Figure 1 Only the stirrups are shown in the diagram, while the longitudinal reinforcement is laid in the conventional manner.

[0044] Compared with the traditional shear connection scheme using only studs, the shear bearing capacity of the shear connection structure in this embodiment is superior to the prior art when using the same amount of steel. The shear bearing capacity is calculated as follows:

[0045] The shear bearing capacity calculation formula for the shear connection structure in this embodiment is as follows:

[0046]

[0047] In the formula, A k The area of ​​the root of the key tooth on the joint surface (m²) 2 );f c 'σ' represents the compressive strength (MPa) of a concrete cylinder; n The normal stress (MPa) on the joint surface; A sm The area of ​​frictional contact on the joint surface (m²) 2 ).

[0048] Calculations show that the shear-resistant connection structure in this embodiment has a shear bearing capacity of 585kN.

[0049] The traditional shear capacity calculation formula for stud connections is as follows:

[0050]

[0051] In the formula, A sc The cross-sectional area of ​​the stud (mm²) 2 ); Ec and E s These are the elastic moduli (MPa) of concrete and shear studs, respectively; f cu f is the compressive strength of the concrete cube (MPa); f is the tensile strength of the stud (MPa).

[0052] Calculations show that the shear capacity provided by the stud is 392 kN.

[0053] The comparison shows that the shear bearing capacity of the shear connection structure in this embodiment is 1.49 times that of the stud solution, which means that the shear bearing capacity is increased by 49%.

[0054] In summary, the shear connection structure for steel-ultra-high performance concrete composite bridges provided by this invention overcomes the problems of small bearing surface and inefficient shear bearing capacity of existing connectors, and can effectively connect steel structures and ultra-high performance concrete structures, thereby improving shear bearing capacity.

[0055] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A shear connection structure for a steel-ultra-high performance concrete composite bridge, characterized in that, The system includes steel profiles, ultra-high performance concrete components, and shear keys for connecting the steel profiles and ultra-high performance concrete components. The steel profiles are H-shaped hot-rolled steel profiles. The shear keys are fixed to the top surface of the steel profiles. The shear keys are arranged in single or multiple rows. Each row of shear keys is formed by connecting multiple shear key units sequentially along the longitudinal direction of the steel profile. Each shear key unit includes a corrugated steel plate and vertical components formed on the corrugated steel plate. The corrugated steel plate is fixedly connected to the steel profile, and a longitudinal resistance chamber is formed between the shear key unit and the steel profile, as well as between two adjacent shear key units. The corrugated steel plate includes a first inclined plate, a first horizontal plate connected to the first inclined plate, a second inclined plate connected to the other end of the first horizontal plate, and a third inclined plate connected to the steel profile. The second horizontal plate is connected to the second inclined plate, and the second horizontal plate of the previous shear key unit is connected to the first inclined plate of the next shear key unit. The second horizontal plate is fixedly connected to the steel member. The difference between the width of the steel member and the width of the shear key is greater than 3 times the fiber length. The fiber is the fiber contained in ultra-high performance concrete. The vertical member includes a vertical connector formed on the first horizontal plate and the second horizontal plate, a positioning groove formed on the vertical connector, and a stirrup provided in the positioning groove. The vertical connector is symmetrically distributed on both sides of the longitudinal center line of the first horizontal plate / second horizontal plate. It is obtained by cutting the first horizontal plate / second horizontal plate and bending it 90°. Its cutting line is parallel to the transverse center line of the first horizontal plate / second horizontal plate. When the ultra-high performance concrete component is connected to the steel component, the ultra-high performance concrete fills the longitudinal resistance cavity to form a mortise and tenon structure.

2. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 1, characterized in that, The shear key has a trapezoidal wave shape.

3. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 1, characterized in that, The angles between the first inclined plate and the first horizontal plate, the angles between the first horizontal plate and the second inclined plate, and the angles between the second inclined plate and the second horizontal plate are all 30-150°.

4. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 1, characterized in that, The shear keys are a double-row structure, and the spacing between two adjacent rows of shear keys is greater than or equal to 1.5 times the fiber length.

5. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 1, characterized in that, The positioning groove opening is groove-shaped, semi-circular, or V-shaped, and the stirrup is positioned inside the positioning groove.

6. A steel-ultra-high performance concrete composite bridge, characterized in that, Includes the shear-resistant connection structure according to any one of claims 1-5.

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