A transverse connection structure between a steel box girder and a concrete box girder

Abstract

This utility model discloses a transverse connection structure between a steel box girder and a concrete box girder, including a steel box girder, a concrete box girder, a steel support plate, double rows of high-strength bolts, double rows of transverse reinforcing bars, a perforated steel plate, and shear connectors. This utility model achieves rigid force transmission through a composite connection of welding and double rows of bolts. The double rows of transverse reinforcing bars and the T-joint concrete synergistically enhance the interface's shear and bending resistance. The perforated steel plate and the shear connectors form a three-dimensional shear key, significantly improving shear bearing capacity. The steel support plate serves as a formwork to simplify the construction process. It solves the problems of interface cracking, insufficient shear resistance, and cumbersome construction associated with traditional connection structures. It also features efficient and redundant force transmission, convenient construction, strong interface crack resistance, and excellent durability, making it suitable for transverse node construction in large-span hybrid beam bridges.

Description

Technical Field

[0001] This utility model relates to the field of construction, and in particular to a transverse connection structure between a steel box girder and a concrete box girder. Background Technology

[0002] The combined structure of steel box girder and concrete box girder is widely used in long-span bridges, combining the advantages of lightweight and high strength of steel box girders with the economic durability of concrete box girders. However, the lateral connection nodes between the two still face the following technical bottlenecks in practical engineering:

[0003] Single force transmission path: Traditional connection methods often rely on single-row welding or stud shear members, which can easily lead to stress concentration, insufficient shear resistance at the interface, and fatigue failure under long-term load.

[0004] Low construction efficiency: The connection interface requires additional formwork, the positioning accuracy of the embedded steel bars is difficult to guarantee, and the construction process is complicated and time-consuming.

[0005] Poor interface durability: Under the shrinkage and creep of concrete and changes in ambient temperature and humidity, micro-cracks are easily generated at the joints, and the infiltration of moisture and corrosive media accelerates the deterioration of the structure and affects the service life of the bridge.

[0006] Existing technologies propose sleeve connection schemes, which simplify the rebar butt welding process but fail to address the issue of coordinated three-dimensional force transmission at the steel-concrete interface and lack effective crack-resistant measures. Furthermore, traditional methods employing denser reinforcement or interface roughening, while partially improving interface strength, lead to difficulties in concrete vibration and increase construction costs. Therefore, a novel transverse connection structure is urgently needed that ensures efficient force transmission while also considering ease of construction and interface durability to meet the dual performance and efficiency requirements of modern bridge engineering. Utility Model Content

[0007] To solve the above-mentioned technical problems, this utility model proposes a transverse connection structure between a steel box girder and a concrete box girder.

[0008] The objective of this utility model is achieved through the following technical solution:

[0009] A transverse connection structure between a steel box girder and a concrete box girder includes a steel box girder 1 and a concrete box girder 2 that is transversely connected to the steel box girder 1. A protruding flange 201 protrudes from the upper part of the joint between the steel box girder 1 and the concrete box girder 2, forming a joint between the flange 201 and the steel box girder 1. One end of a steel support plate 3 is fixed to the middle of the end of the steel box girder 1, and the other end of the steel support plate 3 is fixedly connected to the bottom of the flange 201. A perforated steel plate 9 is fixed to the top of the end of the steel box girder 1. Double rows of transverse reinforcing bars 5 are fixed to the middle of the end face of the flange 201. Several first studs 6 are fixed to the middle of the steel support plate 3 as shear connectors. Concrete is poured into the joint to form a connecting concrete block.

[0010] In a further improvement, the upper surfaces of the steel box girder 1 and the concrete box girder 2 are covered with paving concrete 8; the concrete block is T-joint concrete 7, and the surface of the T-joint concrete 7 is flush with the surface of the paving concrete 8.

[0011] Further improvements include a vertical section height of 150-250mm for the T-joint concrete 7, a horizontal flange width of 200-300mm, and an expansion rate of 0.02%-0.05%.

[0012] In a further improvement, the steel support plate 3 is welded to the steel box girder 1; the welding surface of the steel support plate 3 and the steel box girder 1 is sandblasted to a roughness of ≥50μm; the thickness of the steel support plate 3 is 20-40mm.

[0013] Further improvements include the use of 10.9 grade M24 bolts as the double-row high-strength bolts 4, with a row spacing of 80-120mm and a preload force of 1.1-1.3 times the designed anti-slip value.

[0014] In a further improvement, the first studs 6 are arranged in two rows, with adjacent first studs 6 spaced 200-300mm apart along the length of the steel support plate 3, and the height is 1 / 2-2 / 3 of the thickness of the concrete box girder 2; the perforated steel plate 9 has a perforated plate fixed on its surface as a shear connector, the perforation diameter of the perforated plate is 30-50mm, and the spacing between the holes is 2-3 times the hole diameter.

[0015] In a further improvement, a single row of second studs 101 is fixed at the middle of the end of the steel box girder 1, and the second studs 101 are located at the middle of the double row of transverse reinforcing bars 5.

[0016] Further improvements include the use of HRB400 grade threaded steel bars 5 with a diameter ≥16mm, a row spacing of 50-80mm, a single row spacing of 100-150mm, and an anchorage length ≥30 times the diameter of the double row of transverse steel bars.

[0017] As a further improvement, the connection between the steel support plate 3 and the lower surface of the protrusion 201 is bent downward at a 30°-45° angle to enhance the compactness of the joint concrete 7.

[0018] In a further improvement, the end of the transverse reinforcing bar 5 is bent into a hook shape, and the bending length is ≥10 times the diameter of the transverse reinforcing bar.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. High-efficiency and redundant force transmission: The redundant force transmission system is formed by double rows of high-strength bolts and double rows of transverse steel bars, which increases the shear bearing capacity by more than 40%; the perforated steel plate and the stud work together to realize three-dimensional shear force transmission;

[0021] 2. Enhanced flexural stiffness: The flange structure of the T-joint concrete increases the contact area, thereby increasing the interfacial flexural stiffness by 25%.

[0022] 3. Convenient construction: The steel support plate also functions as a formwork, and the double-row bolt connection and pre-welded perforated steel plate simplify construction positioning, shortening the construction period by 20%-30%;

[0023] 4. Interface crack resistance and durability: Micro-expansion concrete compensates for shrinkage deformation, combined with double-row steel reinforcement anchoring and polypropylene fiber incorporation (0.9-1.2kg / m³), crack width ≤0.08mm, and durability life extended to more than 100 years. Attached Figure Description

[0024] The present invention will be further described with reference to the accompanying drawings, but the content of the drawings does not constitute any limitation on the present invention.

[0025] Figure 1 This is a schematic diagram of the transverse connection structure between the steel box girder and the concrete box girder provided in the embodiments of this application;

[0026] Figure 2 This is provided by the embodiments of this application. Figure 1 The front view;

[0027] Figure 3 This is an overall schematic diagram of the transverse connection structure (without poured joint concrete) between the steel box girder and the concrete box girder provided in the embodiments of this application.

[0028] Figure 4 This is an overall schematic diagram of the transverse connection structure (cast joint concrete) between the steel box girder and the concrete box girder provided in the embodiments of this application.

[0029] In the diagram, 1. Steel box girder; 2. Concrete box girder; 3. Steel support plate; 4. Double row of high-strength bolts; 5. Transverse reinforcement; 6. First stud; 7. Joint concrete; 8. Pavement concrete; 9. Perforated steel plate. Detailed Implementation

[0030] To make the purpose, technical solution and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and examples.

[0031] Example 1

[0032] like Figure 1-4As shown in the figure, this application embodiment provides a transverse connection structure between a steel box girder and a concrete box girder, including a steel box girder 1, a concrete box girder 2, a steel support plate 3, double-row high-strength bolts 4, transverse reinforcing bars 5, first studs 6, joint concrete 7, and a perforated steel plate 9. The steel box girder 1 is made of Q345qD steel, and a 30mm thick steel support plate 3 is welded to the end. The surface of the steel support plate 3 is welded with first studs 6 as shear connectors, with a longitudinal spacing of 250mm and a height of 2 / 3 of the thickness of the concrete box girder 2. HRB400Φ20 transverse reinforcing bars 5 are pre-embedded in the concrete box girder 2, with an anchorage length of 600mm and a spacing of 120mm.

[0033] The construction process of the transverse connection structure between a steel box girder and a concrete box girder provided in this application is as follows:

[0034] Step 1: Prefabricate the steel box girder 1 in the factory, and weld the steel support plate 3 and the perforated steel plate 9 to its end; the welding surface on the right side of the steel support plate 3 is sandblasted to a roughness of ≥50μm; double rows of high-strength bolts 4 are set on the left side, with a spacing of 100mm between each row, and the bolt preload is 1.2 times the design anti-slip value.

[0035] Step 2: Weld the first stud 6 of the stud type to the surface of the steel support plate 3, with a spacing of 250mm along the length direction to form an array of shear keys; at the same time, weld the perforated plate on the perforated steel plate 9, with a hole diameter of 40mm and a hole spacing of 80mm.

[0036] Step 3: Hoist the steel box girder 1 to the design position, and connect the left side of the steel support plate 3 to the concrete box girder 2 with double-row high-strength bolts 4, ensuring that the bolt torque deviation is ≤±3%.

[0037] Step 4: Tie the steel reinforcement cage of the concrete box girder 2, and pre-embed double-row transverse steel bars 5 with a row spacing of 60mm and a single row spacing of 120mm. After extending to the joint area, bend them into a hook shape with a bending length of ≥200mm.

[0038] Step 5: Use steel support plate 3 and temporary formwork to support the pouring space of T-joint concrete 7, and control the vertical section height to 200mm and the horizontal flange width to 250mm.

[0039] Step 6: Use C50 micro-expansion concrete with an expansion rate of 0.03% to pour the joint area. When vibrating, focus on filling the hole area of ​​the perforated steel plate 9. Cure for 28 days until the design strength is reached.

[0040] The key details of the transverse connection structure between a steel box girder and a concrete box girder provided in this application are as follows:

[0041] 1. Multifunctional design of steel pallet: The left edge of the steel pallet 3 is chamfered at 45° to enhance the density of the joint concrete 7; its reserved holes (not shown) are used to insert temporary positioning steel bars to simplify construction positioning; the holes of the perforated steel plate 9 penetrate the concrete to form a "pin-locking" effect, which improves the shear bearing capacity of the interface.

[0042] 2. Shear resistance synergy mechanism: The stud-type stud 6 and the perforated steel plate 9 work together, combined with the anchorage design of the double-row transverse reinforcement 5, the shear bearing capacity of the stud is increased by 50%, and the width of the interface crack is ≤0.08mm; the flange structure of the T-joint concrete 7 restrains shrinkage deformation, and the crack inhibition rate is ≥80%.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the essence and scope of the technical solution of this utility model.

Claims

1. A transverse connection structure between a steel box girder and a concrete box girder, comprising a steel box girder (1) and a concrete box girder (2) transversely connected to the steel box girder (1), characterized in that, A protruding flange (201) is formed on the upper part of the joint end of the steel box girder (1) and the concrete box girder (2), and a joint is formed between the protruding flange (201) and the steel box girder (1); one end of the steel support plate (3) is fixed in the middle of the end of the steel box girder (1), and the other end of the steel support plate (3) is fixedly connected to the bottom of the protruding flange (201); a perforated steel plate (9) is fixed on the top of the end of the steel box girder (1); double rows of transverse steel bars (5) are fixed in the middle of the end face of the protruding flange (201); several first studs (6) are fixed in the middle of the steel support plate (3) as shear connectors; concrete is poured into the joint to form a connecting concrete block.

2. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The upper surfaces of the steel box girder (1) and the concrete box girder (2) are covered with paving concrete (8); the concrete block is T-joint concrete (7), and the surface of the T-joint concrete (7) is flush with the surface of the paving concrete (8).

3. The transverse connection structure between the steel box girder and the concrete box girder according to claim 2, characterized in that, The vertical section height of the T-joint concrete (7) is 150-250mm, the horizontal flange width is 200-300mm, and the expansion rate is 0.02%-0.05%.

4. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The steel pallet (3) is welded to the steel box girder (1); the welding surface of the steel pallet (3) and the steel box girder (1) is sandblasted and has a roughness of ≥50μm; the thickness of the steel pallet (3) is 20-40mm.

5. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The steel support plate (3) is connected to the concrete box girder (2) by double-row high-strength bolts (4). The double-row high-strength bolts (4) are M24 bolts of grade 10.9, with a spacing of 80-120mm between each row, and the preload is 1.1-1.3 times the design anti-slip value.

6. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The first studs (6) are arranged in two rows, with adjacent first studs (6) spaced 200-300mm apart along the length of the steel support plate (3), and the height is 1 / 2-2 / 3 of the thickness of the concrete box girder (2); the perforated steel plate (9) is fixed with a perforated plate as a shear connector, the hole diameter of the perforated plate is 30-50mm, and the hole spacing is 2-3 times the hole diameter.

7. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The steel box girder (1) has a single row of second studs (101) fixed at the middle of its end, and the second studs (101) are located in the middle of the double row of transverse steel bars (5).

8. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The double-row transverse steel bars (5) are made of HRB400 grade threaded steel with a diameter ≥16mm, a row spacing of 50-80mm, a single row spacing of 100-150mm, and an anchorage length ≥30 times the diameter of the double-row transverse steel bars.

9. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The connection between the steel support plate (3) and the lower surface of the protrusion (201) is bent downward at 30°-45° to enhance the compactness of the joint concrete (7).

10. The transverse connection structure between the steel box girder and the concrete box girder according to claim 1, characterized in that, The end of the transverse steel bar (5) is bent into a hook shape, and the bending length is ≥ 10 times the diameter of the transverse steel bar.

Images