Segmental connection system and construction method of steel core-concrete composite beam

Abstract

This invention discloses a segmental connection system for steel-core-concrete composite beams. The system includes longitudinally adjacent steel-core-concrete composite beams and connecting components for connecting them. Each connecting component includes fastening components for connecting adjacent steel cores and interlocking key components for connecting adjacent concrete outer shell sidewalls. This invention also provides a construction method for the above-mentioned segmental connection system. The segmental connection system of this invention eliminates the need for cast-in-place wet joints at the web, improving the shear strength of the web joints. Furthermore, the interlocking key components ensure the installation accuracy of adjacent steel-core-concrete composite beams, making construction more convenient. This overcomes the technical difficulties of ensuring installation accuracy and weak shear resistance when the concrete outer shell web wall is thin.

Description

Technical Field

[0001] This invention belongs to the field of bridges, and particularly relates to a segmental connection system for beams and its construction method. Background Technology

[0002] In bridge engineering production practice, segmental prefabrication and on-site splicing are common construction methods. However, due to complex on-site environmental factors, there are often practical problems such as difficulty in positioning and connecting beam segments, inaccurate connections, unstable and unreliable connections, and cumbersome construction procedures. These problems greatly reduce the construction speed of bridge projects and seriously hinder the development goal of rapid bridge construction.

[0003] Patent CN114737462A discloses a composite box girder structure and its construction method. This composite box girder structure features simple construction, excellent performance, and moderate cost. However, when constructing the composite box girder structure using segmental prefabrication and on-site splicing, there are two methods for jointing between segments: wet joints and dry joints. For the top slab, wet joints are preferable to prevent future leakage. For the web and bottom slab, if cast-in-place wet joints are used, there are problems such as a large number of wet joints, a large amount of on-site construction work, and low construction accuracy. On the other hand, dry joints are used for the web. When the web wall is thin, ensuring sufficient shear resistance is an urgent technical challenge that needs to be solved. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings and defects mentioned in the background art above, and to provide a segmental connection system and construction method for a steel-core-concrete composite beam with high construction efficiency, high installation accuracy, and strong web shear resistance. To solve the above technical problem, the technical solution proposed by this invention is as follows:

[0005] A segmental connection system for a steel-core-concrete composite beam, wherein the steel-core-concrete composite beam includes a concrete shell and a steel core, the steel core being fitted and fixed inside the concrete shell by shear connectors; the segmental connection system includes steel-core-concrete composite beams arranged adjacent to each other in the longitudinal direction and connecting components for connecting the steel-core-concrete composite beams arranged adjacent to each other in the longitudinal direction, the connecting components including fastening components for connecting adjacent steel cores and interlocking key components for connecting the side webs of adjacent concrete shells (i.e., eliminating wet joints and using dry joints).

[0006] In the aforementioned segmental connection system of the steel-core-concrete composite beam, preferably, the interlocking key assembly includes multiple keys located at the ends of the webs on both sides of the concrete shell. There is space between adjacent keys for accommodating keys at the ends of the webs on the adjacent sides of the concrete shell. The keys at the ends of the webs on the adjacent sides of the concrete shell match and interlock to form a whole. By setting matching keys, the positioning and connection of the composite beam segments can be facilitated, providing convenient positioning and fitting, and also enabling the transmission of shear forces after structural continuity.

[0007] In the segmental connection system of the aforementioned steel-core-concrete composite beam, preferably, the foremost end of the key extends outward beyond the end of the concrete shell, ensuring that during butt joint connection, the interlocking key of this segment can extend into the adjacent segment and contact and engage with the interlocking keys of the adjacent segment. The end of the steel core extends outward to the middle of the longitudinal bridge of the key (to ensure that the ends of adjacent steel cores can fit tightly together during segment connection). The longitudinal bridge of the steel core extends to half the height of the key, thereby covering the weakest point at the root of the key with the steel core. This changes the joint from simple shear resistance by the key to shear resistance by both the key and the steel core, increasing the shear strength of the web joint by 30-40%, reaching a level close to that of a wet joint.

[0008] In the aforementioned segmental connection system of the steel-core-concrete composite beam, preferably, the ends of the webs on both sides of the concrete shell are further provided with concrete plates for concealing the joint formed after the adjacent teeth engage. These concrete plates are located above the teeth, and the concrete plates at adjacent ends of the concrete shell match each other. The concrete plates can be integrally formed with the webs of the concrete shell, and can be used to improve the joint shape after the composite beam segments are joined, making it a straight, flat joint.

[0009] In the segmental connection system of the above-mentioned steel core-concrete composite beam, preferably, the toothed key is integrally formed with the concrete shell, and the toothed key is trapezoidal.

[0010] In the above-mentioned segmental connection system of steel core-concrete composite beam, preferably, the fastening component includes a bolt-fitting steel plate and a bolt. The bolt-fitting steel plate has bolt connection holes. The end of the steel core is fixed with a bolt-fitting steel plate. The bolt connection holes on the bolt-fitting steel plates of adjacent steel cores match each other. The bolt-fitting steel plates of adjacent steel cores fit together and are fixed by bolts to achieve the fixed connection of adjacent steel cores.

[0011] In the segmental connection system of the aforementioned steel core-concrete composite beam, preferably, the outer edge of the bolt-connected steel plate is fixedly connected to the end of the steel core, and the bolt-connected steel plate is arranged perpendicular to the inner wall surface of the steel core. Multiple stiffening steel plates are fixed between the inner wall surface of the steel core and the bolt-connected steel plate. The connection stiffness of the bolt-connected steel plates can be increased by setting the stiffening steel plates.

[0012] In the segmental connection system of the above-mentioned steel core-concrete composite beam, preferably, the stiffening steel plate is set with a variable height, and the height of the side closer to the bolt-connected steel plate is higher than that of the side farther away from the bolt-connected steel plate.

[0013] In the aforementioned segmental connection system of steel-core-concrete composite beams, preferably, the segmental connection system further includes a concrete joint for connecting the tops of adjacent concrete shells. The top surface of the end of the steel-core-concrete composite beam is stepped, with the top plate of the steel core serving as the first step, and the top plate of the concrete shell having a thin layer as the second step. The top surfaces of adjacent steel-core-concrete composite beams after connection form a T-shaped groove, and the concrete joint is cast-in-place within the T-shaped groove. The longitudinal width of the first step is at least 20 cm, and the longitudinal width of the thin layer is at least 20 cm. Reliable connections between the tops of adjacent steel cores and adjacent concrete shells are achieved through fastening components and concrete joints, resulting in a strong, reliable connection between adjacent steel-core-concrete composite beams with good stability.

[0014] In the segmental connection system of the aforementioned steel-core-concrete composite beam, preferably, the concrete shell is provided with two layers of joint structural reinforcement, extending from the concrete shell into the T-slot, and the joint structural reinforcement at the ends of adjacent steel-core-concrete composite beams are matched and connected by tying reinforcement. The two layers of joint structural reinforcement are located within the thin-layer segment and in the concrete layer above the thin-layer segment, respectively, and the length of the reinforcement can be flush with the beam end.

[0015] The steel-core-concrete composite beam of this invention can be used to assemble a main beam. The cross-section of the steel core can be box-shaped or semi-box-shaped. When a semi-box-shaped cross-section is used, it is positioned at the top of the composite beam. The steel core is fitted and fixed inside the concrete shell by shear connectors. The form of the shear connectors is not limited, such as using studs. The material of the concrete shell can be ordinary concrete or UHPC, and the material of the steel core is preferably weathering steel.

[0016] As a general technical concept, the present invention also provides a construction method for the above-mentioned segmental connection system of steel core-concrete composite beam, comprising the following steps:

[0017] S1: Transport the steel core-concrete composite beams that are set up adjacent to each other in the longitudinal direction of the bridge to the installation site and hoist them to the pier cap installation position;

[0018] S2: Make adjacent steel core-concrete composite beams close together. The adjacent steel core-concrete composite beams are initially interlocked and tightly attached by the interlocking key assembly of the side web of the adjacent concrete shell. Then, the adjacent steel cores are connected by the fastening assembly.

[0019] S3: Tie connecting steel bars in the T-slot above the adjacent steel core-concrete composite beam, pour concrete, cure and strengthen it, then tension the longitudinal prestressing tendons to complete the construction.

[0020] In step S2 above, the adjacent steel core-concrete composite beams are brought into close contact using keyways between adjacent beam segments. Because the precast beam segments are equipped with large keyways, after the precast beam segments are hoisted onto the pier abutment, it is only necessary to roughly align the keyways of the adjacent beam segments and then push them together to achieve a highly accurate connection. After accurate connection, the bolt-connecting steel plates on the steel cores of the adjacent beam segments are also connected, with the bolt holes accurately aligned. High-strength bolts are then used to tightly fasten the two beam segments through the bolt holes, thus forming a reliable connection between the steel cores of the adjacent beam segments.

[0021] After the structural connection of the steel core is completed, the stepped joint structure of the top plate of the adjacent beam segment is combined into a T-shaped groove, and the pre-embedded joint structure steel bars are aligned one by one. The connecting steel bars are tied on the aligned pre-embedded joint structure steel bars, and ordinary concrete or UHPC material is poured and cured to form strength, thus completing the docking construction.

[0022] The segmental connection system and corresponding construction method of the steel core-concrete composite beam of the present invention have at least the following advantages: In terms of construction performance: the construction steps are simple and clear, requiring minimal construction equipment and allowing for rapid construction. In terms of mechanical performance: a reliable connection is formed between the entire cross-section of the steel core and the top plate of the outer concrete shell. The web of the concrete shell and the steel core work together to form a reliable shear force transfer. For two adjacent precast segments, reliable structural continuity is formed in the negative bending moment zone at the pier top, and the mechanical performance meets the requirements. In terms of durability: the concrete structure is external, protecting the steel core from corrosion by rain and other environmental factors. The steel core connectors are internal, ensuring good durability, and the force transmission components are high-strength bolts, facilitating operation and maintenance.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] 1. The segmental connection system of the steel core-concrete composite beam of the present invention, by having the steel core and the interlocking key assembly jointly resist shear, eliminates the need for cast-in-place wet joints at the web, thereby improving the shear strength of the web joints. Furthermore, the interlocking key assembly ensures the installation accuracy of adjacent steel core-concrete composite beams, making construction more convenient. It overcomes the technical difficulties such as difficulty in ensuring installation accuracy and weak shear resistance when the concrete shell web wall thickness is thin (e.g., when the web thickness is about 10cm).

[0025] 2. The construction method of the present invention has the advantages of simple and clear construction steps, low requirements for construction equipment, fast construction speed, and high precision. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural schematic diagram of the segmental connection system of the steel core-concrete composite beam in Example 1 (the steel core is a semi-box type).

[0028] Figure 2 This is a magnified view of the joint at the junction of adjacent steel core-concrete composite beams.

[0029] Figure 3 The diagram shows the structure of the construction method in Example 1 (① is the key engagement; ② is the bolt butt steel plate connected by bolts; ③ is the connection between the joint structure reinforcement and the tied connection reinforcement; ④ is the pouring of concrete in the T-slot).

[0030] Figure 4 This is a structural schematic diagram of the segmental connection system of the steel core-concrete composite beam in Example 2 (the steel core is a full box type).

[0031] Legend:

[0032] 1. Steel inner core; 2. Concrete outer shell; 3. Shear connector; 4. Concrete joint; 5. Joint structural reinforcement; 6. Tie-connecting reinforcement; 7. Tooth key; 8. Concrete slab; 10. Bolt butt plate; 11. Bolt; 12. Bolt connection hole; 13. Stiffening plate. Detailed Implementation

[0033] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0034] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0036] Example 1:

[0037] like Figure 1 and Figure 2 As shown, the segmental connection system of the steel-core-concrete composite beam in this embodiment includes a concrete shell 2 (UHPC material) and a steel core 1. The steel core 1 is fixed inside the concrete shell 2 by shear connectors 3 (shear studs), and the steel core 1 is semi-box-shaped. The segmental connection system includes steel-core-concrete composite beams arranged adjacent to each other in the longitudinal direction and connecting components for connecting the steel-core-concrete composite beams arranged adjacent to each other in the longitudinal direction. The connecting components include fastening components for connecting adjacent steel cores 1, interlocking key components for connecting the side webs of adjacent concrete shells 2, and concrete joints 4 for connecting the tops of adjacent concrete shells 2.

[0038] Specifically, in this embodiment, the interlocking key assembly includes multiple key 7 located at the ends of the web plates on both sides of the concrete shell 2. The key 7 is integrally formed with the concrete shell 2. The key 7 is trapezoidal. There is space between the upper and lower adjacent key 7 for accommodating the key 7 at the ends of the web plates on both sides of another adjacent concrete shell 2. The key 7 at the ends of the web plates on both sides of the adjacent concrete shell 2 match each other and interlock into a whole.

[0039] In this embodiment, the foremost end of the toothed key 7 extends outward beyond the end of the concrete shell 2, and the end of the steel inner core 1 extends outward to the middle of the longitudinal bridge of the toothed key 7. When the toothed keys 7 at the ends of the webs on both sides of the adjacent concrete shell 2 match each other and interlock into a whole, the ends of the adjacent steel inner cores 1 can be closely fitted together.

[0040] In this embodiment, the ends of the web plates on both sides of the concrete shell 2 are also provided with concrete plates 8 for covering the joint formed after the adjacent teeth 7 are engaged. The concrete plates 8 are located above the teeth 7, and the concrete plates 8 at the ends of adjacent concrete shells 2 match each other.

[0041] In this embodiment, the key 7 can be configured as an isosceles trapezoid with a thickness of 100mm, a top of 20cm, a base of 80cm, and a height of 30cm, with the 15cm height position precisely positioned at the edge of the segment. The interlocking keys of adjacent segments are arranged alternately to ensure proper key fit and sufficient interlocking after docking. The concrete slab 8, with a thickness of 20mm, ensures sufficient strength, and its edges are flush with the beam end edges to ensure that the joint shape is a straight line after adjacent beam segments are aligned.

[0042] Specifically, in this embodiment, the fastening assembly includes bolt-connecting steel plates 10 and bolts 11. Bolt-connecting steel plates 10 have bolt connection holes 12. Bolt-connecting steel plates 10 are fixed to the ends of the steel inner core 1 (the entire end section of the steel inner core 1 is fixed with bolt-connecting steel plates 10). The bolt connection holes 12 on the bolt-connecting steel plates 10 of adjacent steel inner cores 1 match each other, and the bolt-connecting steel plates 10 of adjacent steel inner cores 1 are fitted together and fixed by bolts 11 to achieve the fixed connection of adjacent steel inner cores 1. The outer edge of the bolt-connecting steel plate 10 is fixed to the end of the steel inner core 1, and the bolt-connecting steel plate 10 is set perpendicular to the inner wall surface of the steel inner core 1. Multiple stiffening steel plates 13 are fixed between the inner wall surface of the steel inner core 1 and the bolt-connecting steel plates 10. The stiffening steel plates 13 are of variable height, with the side closer to the bolt-connecting steel plate 10 having a higher height than the side farther from the bolt-connecting steel plate 10.

[0043] The thickness of the bolt-connected steel plate 10 can be 12mm, and the width can be 150mm. The stiffening steel plate 13 is welded to the steel core 1 and the bolt-connected steel plate 10. It adopts a variable height design, with the side closer to the bolt-connected steel plate 10 being higher, which can be 140mm, and the side farther away from the bolt-connected steel plate 10 being lower, which can be 50mm. This saves materials and is conducive to structural stability.

[0044] In this embodiment, the top surface of the steel core-concrete composite beam end is stepped, with a total thickness of 100mm. The top plate of the steel core 1 is the first step, and the top plate of the concrete shell 2 has a thin section as the second step. The top surface of adjacent steel core-concrete composite beams after connection forms a T-shaped groove, and the concrete joint 4 is cast in place in the T-shaped groove. The concrete shell 2 is provided with two layers of joint structure steel bars 5 (φ12mm), which extend from the concrete shell 2 into the T-shaped groove. The joint structure steel bars 5 at the ends of adjacent steel core-concrete composite beams are matched with each other and connected by tying connection steel bars 6 (φ12mm).

[0045] like Figure 3 As shown, the construction method of the segmental connection system of the steel core-concrete composite beam in this embodiment includes the following steps:

[0046] S1: Transport the steel core-concrete composite beams that are set up adjacent to each other in the longitudinal direction of the bridge to the installation site and hoist them to the pier cap installation position;

[0047] S2: Align the key 7 of the adjacent steel core-concrete composite beams to be connected, push them together and engage them;

[0048] S3: Make the adjacent steel core-concrete composite beams fit together tightly, and make the bolt-butt steel plates 10 of the adjacent steel core 1 fit together. Use bolts 11 through bolt connection holes 12 to fix the bolt-butt steel plates 10 that fit together to achieve the initial fixation of the adjacent steel core-concrete composite beams.

[0049] S4: Connect the joint structural steel bars 5 in the T-slot above the adjacent steel core-concrete composite beams by tying connection steel bars 6;

[0050] S5: Pour ordinary concrete or UHPC into the T-slot above the adjacent steel core-concrete composite beam, cure and develop strength, then tension the external prestressing to complete the construction.

[0051] Using the above construction method, when connecting adjacent beam segments, it is only necessary to roughly align the corresponding key 7 and push them together to fit them. The bolt hole positions and joint positions required for subsequent construction steps can be accurately located, and the construction accuracy can be easily guaranteed.

[0052] In step S3, bolts 11 are used to connect adjacent segments, which makes it easy to ensure the connection strength and can transmit the internal forces of the beam. The bolts 11 are also easy to tighten in later maintenance.

[0053] In step S5, UHPC joints can be cast, resulting in more reliable connection strength.

[0054] Example 2:

[0055] like Figure 4 As shown, the segmental connection system of the steel core-concrete composite beam in this embodiment differs from that in Embodiment 1. In this embodiment, the steel core 1 adopts a box-shaped structure that matches the concrete shell 2, while other structures and construction methods are the same as in Embodiment 1.

Claims

1. A segmental connection system for a steel-core-concrete composite beam, the steel-core-concrete composite beam comprising a concrete shell (2) and a steel core (1), the steel core (1) being fitted and fixed inside the concrete shell (2) by shear connectors (3); characterized in that, The segmental connection system includes steel core-concrete composite beams arranged adjacent to each other in the longitudinal direction and a connection component for connecting the steel core-concrete composite beams arranged adjacent to each other in the longitudinal direction. The connection component includes a fastening component for connecting adjacent steel cores (1) and a key-engaging component for connecting the side webs of adjacent concrete shells (2). The interlocking key assembly includes a plurality of keys (7) located at the ends of the web plates on both sides of the concrete shell (2). There is space between adjacent keys (7) for accommodating another adjacent key (7) at the ends of the web plates on both sides of the concrete shell (2). The keys (7) at the ends of the web plates on both sides of the adjacent concrete shell (2) match each other and interlock into a whole. The front end of the key (7) extends outward beyond the end of the concrete shell (2), and the end of the steel core (1) extends outward to the middle of the longitudinal bridge of the key (7).

2. The segmental connection system according to claim 1, characterized in that, The ends of the web plates on both sides of the concrete shell (2) are also provided with concrete plates (8) for covering the joint formed after the adjacent teeth (7) are engaged. The concrete plates (8) are located above the teeth (7), and the concrete plates (8) at the ends of the adjacent concrete shell (2) match each other.

3. The segmental connection system according to claim 1, characterized in that, The toothed key (7) is integrally formed with the concrete shell (2), and the toothed key (7) is trapezoidal.

4. The segmental connection system according to any one of claims 1-3, characterized in that, The fastening assembly includes a bolt-connecting steel plate (10) and a bolt (11). The bolt-connecting steel plate (10) has a bolt connection hole (12). The end of the steel inner core (1) is fixed with a bolt-connecting steel plate (10). The bolt connection holes (12) on the bolt-connecting steel plates (10) of adjacent steel inner cores (1) match each other. The bolt-connecting steel plates (10) of adjacent steel inner cores (1) are fitted together and fixed by bolts (11) to achieve the fixed connection of adjacent steel inner cores (1).

5. The segmental connection system according to claim 4, characterized in that, The outer edge of the bolt-connected steel plate (10) is fixed to the end of the steel inner core (1), and the bolt-connected steel plate (10) is set perpendicular to the inner wall surface of the steel inner core (1). Multiple stiffening steel plates (13) are fixed between the inner wall surface of the steel inner core (1) and the bolt-connected steel plate (10).

6. The segmental connection system according to any one of claims 1-3, characterized in that, The segmental connection system also includes a concrete joint (4) for connecting the top of adjacent concrete shells (2). The top surface of the steel core-concrete composite beam end is stepped. The top plate of the steel core (1) is the first step. The top plate of the concrete shell (2) is provided with a thin layer as the second step. The top surface of the adjacent steel core-concrete composite beams after they are connected forms a T-shaped groove. The concrete joint (4) is cast in place in the T-shaped groove.

7. The segmental connection system according to claim 6, characterized in that, The concrete shell (2) is provided with two layers of joint structure steel bars (5), which extend from the concrete shell (2) into the T-shaped groove. The joint structure steel bars (5) at the ends of the adjacent steel core-concrete composite beams are matched with each other and connected by tying connection steel bars (6).

8. A construction method for a segmental connection system of a steel-core-concrete composite beam as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Transport the steel core-concrete composite beams that are set up adjacent to each other in the longitudinal direction of the bridge to the installation site and hoist them to the pier cap installation position; S2: Make the adjacent steel core-concrete composite beams close together, and make the adjacent steel core-concrete composite beams initially interlock and stick together through the interlocking tooth key assembly of the side web of the adjacent concrete shell (2), and then connect the adjacent steel cores (1) through the fastening assembly. S3: Tie connecting steel bars in the T-slot above the adjacent steel core-concrete composite beam, pour concrete, cure and strengthen it, then tension the longitudinal prestressing tendons to complete the construction.

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