Top plate overhung hybrid girder bridge combination section structure and closure construction method

Abstract

The invention relates to the technical field of bridge engineering, in particular to a roof-overhung composite girder bridge combination section structure and a closure construction method.The roof-overhung composite girder bridge combination section structure comprises a steel-concrete mixing section, an overhung roof, a bearing plate, a mixing section roof, a mixing section bottom plate, shear nails, PBL shear keys, a concrete beam, a triangular support and a pouring opening, and the steel-concrete mixing section is connected with the concrete beam; the cantilever top plate is formed by performing right-angle sectioning on the combination section; the bearing plate, the steel-concrete mixing section and the cantilever top plate jointly form a combined section whole body; the shear nails and the PBL shear keys are uniformly distributed on the mixing section top plate and the mixing section bottom plate; the pouring openings are evenly distributed in the top plate. According to the invention, the triangular support is arranged below the combination section cantilever top plate by utilizing the internal cavity space of the combination section cantilever top plate, so that safe and efficient hoisting and closure are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge engineering, and in particular to a mixed girder bridge joint segment structure with a cantilevered roof and a closure construction method. BACKGROUND

[0002] Traditional steel-concrete mixed continuous girder bridges use an oblique cutting joint segment structure to hoist and close the mid-span steel girder by crane, which has the following problems: large floating cranes are greatly affected by navigation channel restrictions, and the precise adjustment requirements during closure are high, with extremely great construction difficulty. Bridge cranes are generally modified from hanging baskets or newly manufactured mobile hoisting platform systems. During disassembly and assembly, the coordination efficiency between components or actions is low, especially in narrow operating spaces or complex terrain conditions. Large hoisting equipment is difficult to deploy enough working surfaces due to its large structure, reducing construction efficiency. The slope surface processing complexity is high, and oblique cutting makes it difficult to form a slope surface, which is prone to stress concentration. Oblique welding is too difficult and requires high quality control.

[0003] Therefore, the present application designs a mixed girder bridge joint segment structure with a cantilevered roof and a closure construction method to solve the above technical problems. SUMMARY

[0004] The purpose of the present application is to provide a mixed girder bridge joint segment structure with a cantilevered roof and a closure construction method, which uses the internal cavity space below the cantilevered roof of the joint segment to set up a triangular support, to achieve safe and efficient hoisting and closure, and to solve the problems existing in the prior art.

[0005] To achieve the above purpose, the present application provides the following scheme: the present application provides a mixed girder bridge joint segment structure with a cantilevered roof, comprising: a steel-concrete mixed segment connected to a concrete girder; a cantilevered roof formed by straight-angle cutting of the part below the box girder web of the joint segment, with a straight-angle cross-section and extending along the longitudinal direction; a pressure plate connecting the steel-concrete mixed segment and the cantilevered roof to form a joint segment; a mixed segment roof and a mixed segment floor provided with shear studs and PBL shear keys; pouring openings uniformly arranged on the mixed segment roof; a triangular support installed in the internal cavity of the joint segment to provide support during the construction phase.

[0006] Preferably, the steel-concrete mixed segment and the cantilevered roof form a stepped structure through the connection of the pressure plate.

[0007] Preferably, the shear pins and the PBL shear keys are arranged on the top plate and the bottom plate of the hybrid section.

[0008] Preferably, the triangular support comprises a vertical rod, a horizontal rod and an inclined rod; the vertical rod is fixed to the bearing plate by high-strength bolts or welding; the horizontal rod is fixed to the lower surface of the cantilevered top plate by high-strength bolts or welding; and the inclined rod connects the vertical rod and the horizontal rod.

[0009] Preferably, the triangular supports are arranged along the bridge transversely, and the arrangement interval of adjacent triangular supports is 1.5-2.5 meters.

[0010] The application further discloses a closure construction method applied to the construction of the combined section of the hybrid girder bridge with the cantilevered top plate, and the method comprises the following steps: S1: on-site pouring: completing the concrete pouring of the steel-concrete hybrid section through the pouring opening; S2: triangular support installation: after the bridge structure maintenance reaches the strength, prestress tensioning is performed, and then the triangular support is installed in the internal cavity of the combined section; S3: hoisting system installation: a rigid framework is installed on the top of the steel-concrete hybrid section and the cantilevered top plate, supports are symmetrically arranged on the rigid framework, and pulling jacks are installed on the supports; S4: hoisting system lifting: the pulling jacks are connected with the lifting lugs of the mid-span steel beam through traction ropes, the mid-span steel beam is stably lifted and installed in place; S5: system conversion and support removal: after the mid-span steel beam is installed in place, final concrete pouring is performed, system conversion is completed, and then the triangular support and the hoisting system are removed and recycled.

[0011] Preferably, in the step S3, the rigid framework is composed of double-spliced I-shaped steel arranged longitudinally along the top of the combined section, and is anchored to the concrete beam embedded part through the back-pulling high-strength deformed steel bars.

[0012] Preferably, in the step S3, two pulling jacks are symmetrically arranged on each support, the pulling jacks are through-hole jacks, the traction ropes composed of steel strands are connected with the lifting lugs, and the traction actions of the multiple pulling jacks are synchronously controlled by a computer.

[0013] Preferably, in the step S4, the mid-span steel beam is floated to the bridge site by a transport ship, is preliminarily positioned by using the change of tide level, and is lifted at a speed of 0.5 meters per minute controlled by the pulling jacks.

[0014] Preferably, in the step S2, after the prestress tensioning, the vacuum-assisted pressure grouting method is used for pressure grouting through the prestressed steel strand duct.

[0015] Compared with the prior art, the present application has the following advantages and technical effects: High safety: the risk of stress concentration caused by beveling and the risk of local compression damage of the cantilever roof are completely eliminated.

[0016] Optimized structural performance: the right-angle section minimizes the structural integrity damage to the end of the box girder, avoiding damage to the permanent structure caused by temporary construction measures.

[0017] Convenient construction and controllable quality: the right-angle section makes the formwork production, steel bar installation and concrete pouring more convenient. The quality is easy to check and control, and less affected by the weather.

[0018] Good economy: the complex processing, additional reinforcing steel plates and welding work are saved. The working hours and materials are saved, and the comprehensive cost is reduced.

[0019] Strong applicability: the principle can be widely applied to the hoisting of various large prefabricated components with internal cavities, not limited to the bridge hybrid beam joint section, and can be popularized to the hoisting of large prefabricated structures in the fields of architecture, water conservancy, etc. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings: Figure 1 is a hoisting front view of the present application; Figure 2 is a hoisting side view of the present application; Figure 3 is a general layout diagram of the whole bridge hoisting of the present application; Figure 4 is a top view of the joint section of the present application; Figure 5 is a sectional view of the present application; Figure 6 is a construction method flowchart of the present application In the drawings: 1, steel-concrete hybrid section; 2, cantilever roof; 3, pressure plate; 4, hybrid section roof; 5, hybrid section bottom plate; 6, shear pin; 7, PBL shear key; 8, concrete beam; 9, triangular support; 9-1, vertical rod; 9-2, horizontal rod; 9-3, inclined rod; 10, pouring opening; 11, pulling jack; 12, support; 13, rigid skeleton; 14, traction cable; 15, lifting lug; 16, mid-span steel beam; 17, prestressed steel duct. DETAILED DESCRIPTION

[0021] Clearly, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0023] Referring to Figures 1 to 6 The present embodiment provides a mixed girder bridge joint segment structure with cantilevered roof, comprising: A steel-concrete mixed segment 1 connected with a concrete beam 8; A cantilevered roof 2 formed by straight-angle cutting of the part below the web of the box girder of the joint segment, with a straight-angle cross section and cantilevered and extended along the longitudinal direction; A pressure plate 3 connecting the steel-concrete mixed segment 1 and the cantilevered roof 2 to form the joint segment; A mixed segment roof 4 and a mixed segment floor 5, on which shear studs 6 and PBL shear keys 7 are arranged; Pouring openings 10 uniformly arranged on the mixed segment roof 4; Triangular supports 9 installed in the internal cavity of the joint segment to provide support during the construction stage.

[0024] The present application discloses a mixed girder bridge joint segment structure with cantilevered roof and closure construction method, aiming at the traditional mixed girder bridge hoisting closure construction problem, taking the rigid segment of the steel-concrete mixed segment 1 as the force carrier, and using straight-angle cutting of the steel-concrete mixed segment 1 behind the pressure plate 3 to form the straight-angle cut box girder cantilevered roof 2 steel-concrete mixed segment 1 and the corresponding straight-angle cut angle mid-span steel girder segment. At the same time, the steel-concrete mixed segment 1 cantilevered roof 2 below is mainly supported by the support to prevent local buckling or deformation of the structure caused by hoisting construction load. The jack is directly fixed on the roof of the joint segment, realizing the hoisting-free construction of the mid-span steel girder, and the triangular support 9 is used as the support, forming a stable and clear force transmission structure, so that the internal space is reasonably utilized; the straight-angle cutting greatly reduces the processing difficulty and reduces the stress concentration. The complex crane structure is abandoned, and the stiffness of the concrete beam 8 itself is directly used to support the mid-span closure hoisting, avoiding the assembly and disassembly of the crane, greatly improving the construction efficiency and reducing the construction cost; ensuring the reasonable stress and safety of the structure during the mid-span closure construction process. At the same time, after the closure is completed, the internal support of the box girder can be removed and recycled, saving resources and cost.

[0025] In one embodiment of the present application, the steel-concrete composite section 1 is formed by pouring high-performance concrete through the pouring opening 10 provided at the front of the joint section.

[0026] In one embodiment of the present application, when the overhanging roof 2 is prefabricated in the factory, a numerical control plasma cutting machine is used to accurately cut the end of the box girder, and the cutting surface is at a right angle of 90° with the vertical direction. The roughness of the cutting surface is strictly controlled at Ra≤12.5 μm, and immediately after cutting, the slope surface is sprayed with epoxy zinc-rich primer for corrosion protection treatment.

[0027] In a further optimization scheme, the steel-concrete composite section 1 and the overhanging roof 2 form a stepped structure through the connection of the pressure plate 3. The pressure plate 3 is arranged on the stepped structure to connect the steel-concrete composite section 1 and the overhanging roof 2 into a whole joint section. The pressure plate 3 and the right-angle stepped structure jointly act to gradually transfer the rigidity from the concrete beam 8 to the steel beam, thereby reducing stress concentration.

[0028] In one embodiment of the present application, the overhanging roof 2 and the steel-concrete composite section 1 are welded and connected through the pressure plate 3.

[0029] In a further optimization scheme, the shear studs 6 and the PBL shear keys 7 are arranged at intervals on the composite section roof 4 and the composite section floor 5. The shear studs 6 are arranged in a grid shape on the composite section roof 4 and the floor, and the PBL shear keys 7 are arranged with PBL perforated steel plates in the interval area between the shear studs 6. After pouring, they are mechanically engaged with the concrete to significantly improve the shear performance of the bonding surface.

[0030] In one embodiment of the present application, the shear studs 6 are bolt studs with a diameter of 22 mm and a height of 150 mm, arranged in a grid shape with a spacing of 100 mm x 100 mm.

[0031] In a further optimization scheme, the triangular support 9 includes a vertical rod 9-1, a horizontal rod 9-2, and an inclined rod 9-3. The vertical rod 9-1 is fixed to the pressure plate 3 by high-strength bolts or welding. The horizontal rod 9-2 is fixed to the lower surface of the overhanging roof 2 by high-strength bolts or welding. The inclined rod 9-3 connects the vertical rod 9-1 and the horizontal rod 9-2. The triangular support 9 is arranged along the bridge transversely, and the arrangement interval of adjacent triangular supports 9 is 5 meters - 2.5 meters. The triangular support 9 is used for supporting the formwork and temporary load during the construction stage. The triangular support 9 is a triangular truss welded from L100x10 angle steel. The vertical rod 9-1 is fixed to the pressure plate 3 by 10.9 grade M24 high-strength bolts or fillet welds. The horizontal rod 9-2 is fixed to the overhanging end of the overhanging roof 2 by 10.9 grade M24 high-strength bolts or fillet welds. The inclined rod 9-3 connects the intersection of the vertical rod 9-1 and the horizontal rod 9-2 by welding, thereby enhancing the overall stability of the support.

[0032] The present application also discloses a closure construction method for the composite girder bridge joint section structure of the overhanging roof, comprising the following steps: S1: On-site pouring: The concrete of the steel-concrete composite section 1 is poured through the pouring port 10; the steel-concrete composite section 1 is poured on-site through the pouring port 10, and the concrete is tightly connected to the bearing plate 3 by bonding. The pouring is carried out in layers, first pouring the bottom cavity and then pouring the top cavity, and the pouring speed is controlled to be ≤1m³ / h. Vibration is carried out by using an attached vibrator in combination with a φ30mm immersion vibrator, focusing on strengthening the compaction around the holes of the bearing plate 3.

[0033] S2: Triangular bracket installation: After the bridge structure has reached its strength, triangular brackets 9 are installed in the internal cavity of the joint section; after the installed bridge structure has reached its strength, prestressed steel strands are tensioned through prestressed steel strand ducts 17, and then grouting is carried out using vacuum-assisted grouting to reduce stress deformation and seal the prestressed steel strand ducts 17; then the triangular brackets are precisely positioned and installed in the internal cavity, arranged along the transverse direction of the bridge, with the uprights 9-1 bolted or welded to the bearing plate 3; the crossbars 9-2 bolted or welded to the lower surface of the cantilevered top plate 2; the brackets are arranged along the transverse direction of the bridge at intervals of 1.5-2.5m, with the main uprights 9-1 fixed to the bearing plate 3 by 10.9 grade M24 high-strength bolts or fillet welds; the top crossbars 9-2 are fixed to the lower surface of the cantilevered top plate 2 by 10.9 grade M24 high-strength bolts or fillet welds.

[0034] S3: Installation of the hoisting system: A rigid frame 13 is installed on the top of the steel-concrete mixed section 1 and the cantilevered roof slab 2, and supports 12 are symmetrically arranged on the rigid frame 13. Pulling jacks 11 are installed on the supports 12. The rigid frame 13 is installed on the top of the steel-concrete mixed section 1 and the cantilevered roof slab 2. Then, supports 12 are symmetrically arranged on the rigid frame 13, and pulling jacks 11 are installed through the supports 12. The rigid frame 13 uses double-span I40a I-beams arranged longitudinally along the top of the combined section. It is anchored to the embedded parts of the concrete beam 8 by precision-rolled threaded reverse tension. The supports 12 are placed according to the lifting point positions. Two 200t through-hole jacks are symmetrically arranged on each support 12. The lifting lugs 15 of the mid-span steel beam 16 are connected by steel strand traction. The pulling jacks 11 are synchronously controlled by computer.

[0035] S4: Lifting System: Using traction jacks 11 connected to the lifting lugs 15 of the mid-span steel beam 16 via traction cables 14, the mid-span steel beam 16 is smoothly lifted and installed in place; using traction jacks 11 connected to the lifting lugs 15 via traction cables 14, the mid-span steel beam 16 is smoothly lifted for installation; the mid-span steel beam 16 is floated to the bridge site by a transport ship, and its initial positioning is achieved using tidal changes. The traction jacks 11 synchronously pull the steel beam upwards at a controlled speed of 0.5 m / min. After the steel beam is lifted to the design elevation, its horizontal positioning is completed using the sand box fine-tuning system and limit devices on the support frame.

[0036] S5: System Conversion and Support Removal: After the mid-span steel beam 16 is installed and in place, the final concrete pouring of the connecting section completes the system conversion. Subsequently, the triangular support 9 and the hoisting system are removed and recycled. After the mid-span steel beam 16 is installed and connected, the entire connecting section is poured through the pouring port 10 to complete the system conversion. Finally, the support is removed and recycled, completing the closure. Finally, concrete is poured into the remaining gaps of the connecting section through the pouring port 10 located on the top slab. After the concrete reaches its strength, the hoisting system and internal supports are removed and recycled, completing the closure construction.

[0037] In further optimization of the scheme, in step S3, the rigid frame 13 adopts double-jointed I-beams arranged longitudinally along the top of the joint section and anchored to the embedded parts of the concrete beam by reverse tensioning with finely rolled threaded steel bars.

[0038] To further optimize the scheme, in step S3, two traction jacks 11 are symmetrically arranged on each support 12. The traction jacks 11 are through-hole jacks, which are connected to the lifting lugs 15 through the traction cable 14 made of steel strands. The traction action of multiple jacks is controlled synchronously by a computer.

[0039] To further optimize the plan, in step S4, the mid-span steel beam 16 is floated to the bridge site by a transport ship, initially positioned using tidal changes, and then lifted at a speed of 0.5 meters per minute by pulling jacks 11.

[0040] In further optimization of the scheme, in step S2, after prestressing tensioning, grouting is carried out through the prestressed steel strand duct 17 using vacuum-assisted grouting method.

[0041] Through the above-described specific embodiments, this invention successfully transforms the internal space of the box girder into an effective load-bearing structure, forming a clear and efficient force transmission path of "rigid skeleton 13 → cantilevered top plate 2 → triangular support → main structure". This not only solves the technical pain points of traditional oblique cutting schemes, but also demonstrates significant advantages in safety, economy and construction efficiency, providing a reliable technical example for the construction of hybrid beam joint sections of similar long-span bridges.

[0042] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0043] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A mixed beam bridge joint segment structure of a cantilevered roof, characterized by, The utility model relates to a steel-concrete hybrid segment (1) connected with a concrete beam (8), a cantilever roof (2) formed by straight-angle cutting of the lower part of the box girder web of the joint segment, the cross section of which is in the shape of a right angle and extends longitudinally, a bearing plate (3) connecting the steel-concrete hybrid segment (1) and the cantilever roof (2) to form the joint segment, a hybrid segment roof (4) and a hybrid segment floor (5) provided with shear studs (6) and PBL shear keys (7), pouring openings (10) uniformly arranged on the hybrid segment roof (4), and triangular supports (9) installed in the internal cavity of the joint segment to provide support during construction. The steel-concrete hybrid segment (1) and the cantilever roof (2) form a stepped structure through the connection of the bearing plate (3). The shear studs (6) and the PBL shear keys (7) are arranged at intervals on the hybrid segment roof (4) and the hybrid segment floor (5). The triangular support (9) comprises a vertical rod (9-1), a horizontal rod (9-2), and an inclined rod (9-3). The vertical rod (9-1) is fixed to the bearing plate (3) by high-strength bolts or welding. The horizontal rod (9-2) is fixed to the lower surface of the cantilever roof (2) by high-strength bolts or welding. The inclined rod (9-3) connects the vertical rod (9-1) and the horizontal rod (9-2). The triangular supports (9) are arranged along the transverse direction of the bridge, and the arrangement interval of adjacent triangular supports (9) is 1.5-2.5 meters. The method comprises the following steps: S1: on-site pouring: concrete pouring of the steel-concrete hybrid segment (1) is completed through the pouring openings (10); 2. The hybrid girder bridge joint segment construction of a roof overhang according to claim 1, characterized in that: S2: triangular support installation: after the bridge structure is cured to reach the strength, prestressed tensioning is performed, and then the triangular supports (9) are installed in the internal cavity of the joint segment; 3. The hybrid girder bridge joint segment with overhanging roof according to claim 1, characterized in that: S3: hoisting system installation: a rigid framework (13) is installed on the top of the steel-concrete hybrid segment (1) and the cantilever roof (2), supports (12) are symmetrically arranged on the rigid framework (13), and pulling jacks (11) are installed on the supports (12); 4. The top-flap cantilevered hybrid girder segment construction of claim 1, wherein: S4: hoisting system lifting: the pulling jacks (11) are connected to the lifting lugs (15) of a mid-span steel beam (16) through traction cables (14), the mid-span steel beam (16) is smoothly lifted and installed in place; 5. The hybrid girder bridge segment construction with cantilevered roof according to claim 4, characterized in that: S5: system conversion and support removal: after the mid-span steel beam (16) is installed in place, final concrete pouring is performed, system conversion is completed, and then the triangular supports (9) and the hoisting system are removed and recycled.

6. A closure construction method for constructing the top plate cantilevered hybrid girder bridge joint section structure according to any one of claims 1-5, characterized in that, In step S3, the rigid framework (13) is composed of double-spliced I-beams arranged longitudinally on the top of the joint segment and anchored to the concrete beam embedded parts through reverse pulling of the finished rolled threaded steel bars. In step S3, two pulling jacks (11) are symmetrically arranged on each support (12). The pulling jacks (11) are through-hole jacks, the traction cables (14) composed of steel strands are connected to the lifting lugs (15), and the traction actions of multiple jacks are synchronously controlled by a computer. ​ ​ ​ ​ 7. The closure construction method according to claim 6, characterized in that: ​ 8. The closure construction method according to claim 7, characterized in that: ​ 9. The closure construction method according to claim 6, characterized in that: In the step S4, the midspan steel beam (16) is floated to the bridge site by the transport ship, preliminarily positioned by the change of the tide level, and controlled to be lifted at a speed of 0.5 m / min by the pulling jack (11).

10. The closure construction method according to claim 6, characterized in that: In the step S2, after the prestress tension, the vacuum-assisted grouting method is used for grouting through the prestress steel strand duct (17).

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