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

Abstract

The invention provides a shear connection structure of a steel-ultra-high performance concrete composite bridge. The shear connection structure comprises a profile steel member, an ultra-high performance concrete member and a shear key used for connecting the profile steel member and the ultra-high performance concrete member. The shear keys are arranged in a single row or multiple rows, each row of shear keys is formed by sequentially connecting a plurality of shear key units in the longitudinal direction of the profile steel component, each shear key unit comprises a corrugated steel plate and a vertical component formed on the corrugated steel plate, and the corrugated steel plates are fixedly connected with the profile steel component. Longitudinal resistance cavities are formed between the shear key units and the profile steel component and between every two adjacent shear key units. When the ultra-high-performance concrete member is connected with the profile steel member, the longitudinal resistance cavity is filled with ultra-high-performance concrete, and a mortise and tenon joint structure is formed. According to the shear-resistant connecting structure of the steel-ultra-high-performance concrete combined bridge, the steel structure and the ultra-high-performance concrete structure can be effectively connected, the shear-resistant bearing capacity is improved, and arrangement of steel bars is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to a steel-ultra-high performance concrete composite bridge and a shear-resistant connection structure thereof. Background Art

[0002] Since the development of bridges, the bridge system has covered various types such as concrete bridges, steel bridges, and steel-concrete composite bridges. Ultra-high performance concrete is a new type of composite cement-based material with a compressive strength of over 120MPa and a tensile strength of over 7MPa. The advent of ultra-high performance concrete has promoted the innovation of bridge structures, especially its application in the field of steel-concrete composite bridges 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 connection interface between the two. The bonding effect between steel and concrete at the interface is very small, and bonding failure is very likely to occur. How to effectively connect the two materials, steel and ultra-high performance concrete, is a technical key and difficulty. Since shear slip will occur at the connection interface between the two materials under the action of vehicle loads, shear-resistant connection components have become an important part of the steel-concrete composite structure. The design of shear-resistant connection components needs to effectively prevent horizontal slip separation at the interface between steel and concrete, so that the steel structure and concrete structure with large differences in elastic modulus can work together to safely transfer vehicle loads to the bridge piers.

[0004] The main function of shear connectors is to resist horizontal shear force and vertical lifting force. Currently, common shear connection structures are mostly welded on steel structures using bolts and perforated steel plates. These two construction processes are mature, but there are still deficiencies in terms of force. For example, the effective pressure-bearing surface of the bolts is only the root area, and the effective pressure-bearing surface of the perforated steel plate is the perforated area. The force-bearing cross-sectional areas of both are relatively small, resulting in low bearing capacity of the shear connection structure. The number of bolts and perforated steel plates welded needs to be increased to improve the structural bearing capacity. In addition, another important issue that needs to be solved in the shear connection structure is the arrangement of steel bars in the concrete structure. Dense bolts and perforated steel plates will hinder the arrangement of steel bars, increasing the difficulty of construction.

[0005] Therefore, a new shear-resistant connection structure is urgently needed to solve the above 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 pressure-bearing surface and low shear bearing capacity of existing connectors, can effectively connect steel structures and ultra-high performance concrete structures, improve shear bearing capacity, and facilitate the arrangement of steel bars.

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

[0008] A shear connection structure of a steel-ultra-high performance concrete composite bridge, comprising a steel member, an ultra-high performance concrete member, and a shear key for connecting the steel member and the ultra-high performance concrete member; the shear keys are arranged in a single row or multiple rows, each row of shear keys is formed by a plurality of shear key units connected in sequence along the longitudinal direction of the steel member, the shear key unit comprises a corrugated steel plate and a vertical member formed on the corrugated steel plate, the corrugated steel plate is fixedly connected to the steel member, and a longitudinal resistance chamber is formed between the shear key unit and the steel member, and between two adjacent shear key units;

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

[0010] Furthermore, the shear key is in 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, and the second horizontal plate of the previous shear key unit is connected to the first inclined plate of the subsequent shear key unit, and the second horizontal plate is fixedly connected to the steel structure.

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

[0013] Furthermore, the difference between the width of the steel member and the width of the shear key is greater than 3 times the fiber length, and the fiber is the fiber contained in ultra-high performance concrete.

[0014] Furthermore, the shear keys are of 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 connection piece formed on the first horizontal plate and the second horizontal plate, a positioning groove formed on the vertical connection piece, and a stirrup disposed 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 / the second horizontal plate, and are obtained by cutting the first horizontal plate / the second horizontal plate and then bending it 90°, and the cutting line is parallel to the transverse center line of the first horizontal plate / the second horizontal plate.

[0017] Furthermore, the positioning groove opening is groove-shaped, semicircular or V-shaped, and the stirrup is positioned in the positioning groove.

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

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

[0020] 1. The shear connection structure of the steel-ultra-high performance concrete composite bridge provided by the present invention is formed by connecting a plurality of shear key units in sequence along the longitudinal direction of the steel member. The shear key unit includes a corrugated steel plate and a vertical member, and a longitudinal resistance chamber is formed between the shear key unit and the steel member, and between two 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 to form a mortise and tenon structure, which provides a shear effect in the longitudinal direction, and can effectively weaken the shear force of interface slip. Moreover, due to the large force-bearing area of ​​the longitudinal resistance chamber, a higher shear bearing capacity is provided; at the same time, the longitudinal resistance chamber and the vertical member provide a dual pull-out effect in the height direction. Therefore, the shear connection structure of the steel-ultra-high performance concrete composite bridge provided by the present invention overcomes the problems of small pressure-bearing surface and low shear bearing capacity of existing connectors, and can effectively connect steel structures and ultra-high performance concrete structures to improve shear bearing capacity.

[0021] 2. In the shear connection structure of the steel-ultra-high performance concrete composite bridge provided by the present invention, the second horizontal plate of the shear key is welded and fixed on the steel member, and then the stirrups are positioned in the positioning grooves, the formwork is set up, and the ultra-high performance concrete is poured to achieve the connection between the ultra-high performance concrete and the steel member, with high construction efficiency, convenient stirrup arrangement, and simple operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 It 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 Schematic diagram of the connection between the medium-sized steel member and the shear key in the shear connection structure;

[0025] Figure 3 for Figure 2 Schematic diagram of some structures;

[0026] Figure 4 for Figure 2 Schematic diagram of the shear bond unit structure. DETAILED DESCRIPTION

[0027] In order 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 objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are further described below.

[0028] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0029] Please refer to Figures 1 to 4 ,in Figure 1 It 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 Schematic diagram of the connection between the medium-sized steel member and the shear key in the shear connection structure; Figure 3 for Figure 2 Schematic diagram of some structures; Figure 4 for Figure 2 Schematic diagram of the shear key unit structure in the steel-ultra-high performance concrete composite bridge of the present invention comprises a steel member 1, an ultra-high performance concrete member 2, and a shear key 3 for connecting the steel member 1 and the ultra-high performance concrete member 2. The steel member 1 is an H-shaped hot-rolled steel member, which has the advantages of less welding work and less residual stress, and the shear key 3 is fixed to the top surface of the steel member 1.

[0030] In the present invention, the shear key 3 is arranged in a single row or multiple rows, and each row of shear keys is formed by connecting a plurality of shear key units 31 in sequence along the longitudinal direction of the steel member. The 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, and between two adjacent shear key units 31. Preferably, the shear keys 3 are symmetrically distributed along the longitudinal center line of the steel member and are in a trapezoidal wave shape.

[0031] In this embodiment, the shear key 3 is 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, and 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, and the shear key unit is fixedly connected to the steel member 1 through the second horizontal plate 3114, such as by welding. In a specific application, the first inclined plate, the first horizontal plate, the second inclined plate and the second horizontal plate are formed by bending steel plates, that is, the shear key unit is an integrally formed structure; it can also be formed by welding and fixing the first inclined plate, the first horizontal plate, the second inclined plate and the second horizontal plate in sequence.

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

[0033] The thickness of the steel plate used in the shear key unit 31 is 0.5-1 cm, and the length of each plate is 5-15 cm. The width is adjusted according to the width of the steel member, and 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 the ultra-high performance concrete, so as to ensure that there is at least 1.5 times the fiber length on both sides of the shear key, which is conducive to the flow and distribution of the fiber during pouring. When the shear key 3 is designed in multiple rows, the difference between the width of the steel member and the sum of the widths of the shear key is greater than 3 times the fiber length, and the spacing between two 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 may also be in other shapes, such as an arc wave shape. Correspondingly, the vertical member is arranged at the wave crest position of the shear key 3 .

[0035] The vertical member 312 is used to provide anti-pullout effect, which 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 connector 3121 is symmetrically distributed on both sides of the longitudinal center line of the first horizontal plate / the second horizontal plate, and is obtained by cutting the first horizontal plate / the second horizontal plate and bending it 90°. Preferably, its cutting line is parallel to the transverse center line of the first horizontal plate / the second horizontal plate, and is symmetrically distributed on both sides of the transverse center line of the first horizontal plate / the second horizontal plate. In other words, at least two vertical connectors are respectively provided on the first horizontal plate / the second horizontal plate. The width of the vertical connector 3121 is 3-6cm, and the height is 4-6cm.

[0036] The positioning groove 3122 is used for positioning the stirrups, and the shape of the groove opening can be a groove, a semicircle or a V-shape, and the opening depth is 1-1.5 cm. During the specific 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 has the following construction method:

[0038] (1) Design the shear key dimensions, including the width of the shear key steel plate, the bending angle, the length of each plate in the shear key unit, etc., 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) Shear key units are manufactured according to design requirements, the second horizontal plate of the preceding shear key unit is welded to the first inclined plate of the succeeding shear key unit, and then the second horizontal plate of each shear key unit is welded to the top surface of the steel member to achieve installation and fixation of the corrugated steel plate, and then the stirrups are positioned in the positioning grooves of the vertical connectors;

[0040] (3) Setting up formwork, pouring UHP concrete, forming UHP concrete components, and realizing the connection between UHP concrete components and steel components. During the pouring of UHP concrete, the UHP concrete fills the longitudinal cavity formed by the shear key, so that the UHP concrete components form a mortise and tenon structure, which not only provides shear resistance in the longitudinal direction and effectively weakens the shear force of interface slip, 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 is described in detail below through specific embodiments.

[0042] The angles between the first inclined plate and the first horizontal plate, the angle between the first horizontal plate and the second inclined plate, and the angle between the second inclined plate and the second horizontal plate of the corrugated steel plate in the shear key unit are 120° respectively. 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. The notch of the positioning groove is 1cm deep and the opening is groove-shaped. The construction method is as follows:

[0043] All components of the composite beam are prefabricated in a prefabrication plant. When the shear key unit is prefabricated, the straight steel plate is bent 120° three times to form a corrugated steel plate structure, and then a 5cm long and 3cm wide steel plate is cut from the horizontal plate along its transverse center line, and then bent 90° to obtain a vertical connector, and a groove opening with a depth and length of 1cm is cut at the top of the vertical connector along the transverse center line. The shear key unit is then welded to the top plate of the steel member through the second horizontal plate, and the front and rear shear key units are connected by butt welding through the first inclined plate and the second horizontal plate, finally forming a shear key distributed along the longitudinal direction of the steel member. The longitudinal steel bars are then laid, stirrups are arranged, and ultra-high performance concrete is poured to obtain a steel-ultra-high performance concrete composite bridge ( Figure 1 Only stirrups are shown, while the longitudinal reinforcement is laid in the conventional manner).

[0044] Compared with the conventional connection scheme using only bolts, the shear bearing capacity of the shear connection structure of this embodiment is better than that of the prior art when the amount of steel used is equal. The shear bearing capacity is calculated as follows:

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

[0046]

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

[0048] Through calculation, the shear bearing capacity of the shear connection structure of this embodiment is 585kN.

[0049] The shear bearing capacity calculation formula of the traditional stud connection scheme is as follows:

[0050]

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

[0052] Through calculation, the shear bearing capacity provided by the studs is 392kN.

[0053] From this comparison, it can be seen that the shear bearing capacity of the shear connection structure of this embodiment is 1.49 times that of the stud solution, that is, the shear bearing capacity is improved by 49%.

[0054] In summary, the shear connection structure of the steel-ultra-high performance concrete composite bridge provided by the present invention overcomes the problems of small pressure-bearing surface and low shear bearing capacity of existing connecting parts, and can effectively connect steel structures and ultra-high performance concrete structures to improve shear bearing capacity.

[0055] The embodiments of the present invention are 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 are still within the protection scope of the present invention.

Claims

1. A shear connection structure of a steel-ultra-high performance concrete composite bridge, characterized in that: The invention comprises a steel member, an ultra-high performance concrete member, and a shear key for connecting the steel member and the ultra-high performance concrete member; the shear keys are arranged in a single row or multiple rows, each row of shear keys is formed by a plurality of shear key units connected in sequence along the longitudinal direction of the steel member, the shear key unit comprises a corrugated steel plate and a vertical member formed on the corrugated steel plate, the corrugated steel plate is fixedly connected to the steel member, and a longitudinal resistance chamber is formed between the shear key unit and the steel member, and between two adjacent shear key units; When the ultra-high performance concrete member is connected to the steel member, the ultra-high performance concrete fills the longitudinal resistance chamber 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 is characterized in that: The shear key is in a trapezoidal wave shape.

3. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 2, characterized in that: 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 previous shear key unit is connected to the first inclined plate of the subsequent shear key unit, and the second horizontal plate is fixedly connected to the steel structure.

4. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 3 is characterized in that: The included angle between the first inclined plate and the first horizontal plate, the included angle between the first horizontal plate and the second inclined plate, and the included angle between the second inclined plate and the second horizontal plate are all 30-150 degrees.

5. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 4, characterized in that: The difference between the width of the steel member and the width of the shear key is greater than 3 times the fiber length, and the fiber is the fiber contained in ultra-high performance concrete.

6. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 5, characterized in that: The shear keys are of 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.

7. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 3, characterized in that: The vertical member includes a vertical connection piece formed on the first horizontal plate and the second horizontal plate, a positioning groove formed on the vertical connection piece, and a stirrup disposed in the positioning groove.

8. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 7, characterized in that: The vertical connecting members are symmetrically distributed on both sides of the longitudinal center line of the first horizontal plate / the second horizontal plate, and are obtained by cutting the first horizontal plate / the second horizontal plate and then bending it 90°, and the cutting line is parallel to the transverse center line of the first horizontal plate / the second horizontal plate.

9. The shear connection structure of the steel-ultra-high performance concrete composite bridge according to claim 7, characterized in that: The positioning groove opening is groove-shaped, semicircular or V-shaped, and the stirrup is positioned in the positioning groove.

10. A steel-ultra-high performance concrete composite bridge, characterized in that: The invention comprises the shear-resistant connection structure according to any one of claims 1 to 9.

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