A prefabricated V-shaped rigid frame bridge and its construction method

Abstract

This invention discloses a prefabricated V-shaped rigid frame bridge and its construction method. The prefabricated V-shaped rigid frame bridge includes: pier foundations, at least two V-legs, and a main girder. The V-legs are composed of multiple prefabricated segments stacked together, with the bottom fixed to the pier foundation via a post-cast section and the top having a cast-in-place section. The main girder includes a No. 0 segment beam and multiple symmetrically arranged prefabricated segments. The prefabricated segments of the main girder are constructed using the inverted beam method, i.e., the top slab, then the web, and finally the bottom slab are prefabricated in sequence. The cast-in-place section of the No. 0 segment beam is integrally cast with the top cast-in-place section of the V-legs. This invention achieves rapid and standardized prefabrication and assembly of variable cross-section beams and V-legs through prefabrication and inverted beam method templates, shortening the construction cycle, reducing the risks of high-altitude operations and traffic interference, improving quality and durability, and possessing economic and environmental advantages.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to a prefabricated V-shaped rigid frame bridge and its construction method. Background Technology

[0002] V-shaped rigid frame bridges, as a type of bridge with high aesthetic value and structural efficiency, effectively shorten the calculated span of the main girder and significantly reduce the mid-span bending moment due to their unique V-shaped support structure. This results in a smaller beam cross-section height and saves engineering materials. This structural form greatly enhances the overall stiffness of the bridge, improves its deflection performance, and presents a light and modern aesthetic, thus finding wide application in various scenarios such as high mountain canyons and urban overpasses. Especially in high-speed railway or urban rail transit projects, V-shaped rigid frame bridges are highly favored due to their superior thrust stiffness and stability.

[0003] However, traditional V-shaped rigid frame bridges mainly rely on cast-in-place construction. This method has many inherent technical bottlenecks and challenges: ① Long construction cycle and low efficiency: Cast-in-place construction involves a series of processes, including rebar tying, formwork erection, concrete pouring, curing, and formwork removal. Especially for structures like the V-legs, which are inclined and have complex spatial shapes, the design, erection, and dismantling of the formwork system is extremely labor-intensive and technically challenging, significantly extending the construction cycle. ② High-risk high-altitude operations and difficulty in ensuring safety: The construction of the V-legs and main beams typically involves high-altitude operations, with a lot of wet work on site. The transportation and handling of personnel and materials are accompanied by high safety risks. ③ Unstable quality control: The on-site construction environment is complex and variable, easily affected by weather, temperature, humidity, and other natural conditions, making it difficult to guarantee the uniformity and strength stability of the concrete. At the same time, human factors such as on-site rebar positioning and formwork precision control can easily introduce quality defects. ④ Large environmental impact and resource consumption: Cast-in-place construction generates a large amount of construction waste, dust, and noise pollution, causing significant disturbance to the surrounding environment. Furthermore, the consumption of large quantities of formwork, supports, and other reusable materials also leads to resource waste.

[0004] To overcome the drawbacks of traditional cast-in-place construction, prefabricated construction technology has emerged. Prefabricated bridges achieve an industrialized production model of "building bridges like building cars" by prefabricating major components in factories and then transporting them to the site for assembly. The advantages of this model are obvious: the factory production environment allows for strict quality control and is unaffected by weather; standardized component production improves efficiency and reduces costs; and reduced on-site work shortens the construction period and reduces safety risks and environmental pollution. Although prefabricated technology has been successfully applied in conventional beam and slab bridges, its application in the complex V-shaped rigid frame bridge field still faces challenges. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a prefabricated V-shaped rigid frame bridge and its construction method, aiming to solve the problems in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a prefabricated V-shaped rigid frame bridge, comprising: Pier foundation; At least two V-legs, each of which consists of multiple precast V-leg segments stacked along the height direction, the bottom of which is fixed to the pier foundation through a post-cast V-leg bottom segment, and the top of which is provided with a cast-in-place V-leg top segment; The main beam includes segment 0 and multiple precast main beam segments symmetrically arranged on both sides of segment 0 along the longitudinal direction. The multiple precast main beam segments include segment 1, segment 2, segment 3 and segment 4. The precast main beam segments are constructed using the inverted beam method. The No. 0 segment beam further includes a cast-in-place No. 0 segment beam and at least one precast No. 0 segment beam, wherein the cast-in-place No. 0 segment beam is integrally cast with the cast-in-place V-leg top segment beam.

[0007] Furthermore, shear keys are provided on the splicing surfaces between the precast V-leg segments, between the precast segment of segment 0 and the adjacent cast-in-place segment of segment 0, and between the precast segments of each main beam. The shear keys are mutually matching tenon and mortise structures. Adjacent segments are bonded together with structural adhesive and temporary pre-tightening force is applied by a temporary pre-tightening device.

[0008] Furthermore, the V-leg and the main beam are equipped with prestressed steel strand ducts that run through the segments, which are used to insert and tension the permanent prestressed steel strands after the segments are assembled.

[0009] Furthermore, the V-legs and main beams are of uniform or variable cross-section. When the V-legs and main beams are of variable cross-section, their precast segments are matched with a variable cross-section formwork system. The main beam segments are precast using the inverted beam method. The variable cross-section formwork system includes inner and outer formwork and end formwork. The inner and outer formwork includes outer formwork and inner formwork. The inner and outer formwork and end formwork are equipped with vertical active expansion joints, horizontal active expansion joints, and passive expansion joints. The formwork size is changed by adjusting the expansion joints to adapt to changes in beam height, bottom plate width, and web thickness. The changing section of the expansion joint is closed with an isolation sleeve.

[0010] Furthermore, the V-leg bottom post-cast section is a conventional reinforced concrete structure, a steel-reinforced concrete structure, or a UHPC structure.

[0011] Furthermore, the connection structure between the bottom of the V-leg and the pier foundation is any one of the following: a. The V-leg bottom post-cast section is a cast-in-place concrete structure; b. The first V-leg precast section connected to the pier foundation 1 is directly connected to the pier foundation 1 through a grouting sleeve or socket connection structure, and the post-cast section at the bottom of the V-leg is eliminated.

[0012] A construction method for a prefabricated V-shaped rigid frame bridge includes the following steps: Step S1: Prefabricate V-leg prefabricated segments and main beam prefabricated segments in the factory or on site. During prefabrication, shear keys are set on the segment splicing surface, and prestressed steel strand ducts are pre-embedded. When prefabricating variable cross-section main beam segments, the inverted beam method is used for prefabrication. Step S2: Construct the pier foundation on site, and pre-install reinforcing bars or connecting structures to the V-legs on the pier foundation; Step S3: Assemble the V-legs. Hoist multiple prefabricated V-leg sections sequentially from bottom to top, match and splice them using shear keys and structural adhesive, and apply temporary pre-tightening force using a temporary pre-tightening device to form the V-leg structure. Step S4: Pour the post-cast section at the bottom of the V-leg to solidify the assembled bottom of the V-leg with the pier foundation; Step S5: Cast the top section of the V-leg and the cast-in-place section of segment 0 beam. Connect the top reinforcement of the V-legs on both sides to the reinforcement of the cast-in-place section of segment 0 beam. After setting up the formwork, pour the concrete in one go to form a rigid joint. Step S6: Assemble the main beam. With the V-leg and segment 0 as the center, hoist the precast segment 0 and each precast segment of the main beam symmetrically to both sides. Match and splice them using shear keys and structural adhesive, and apply temporary pre-tightening force using a temporary pre-tightening device. Step S7: After the segment splicing is completed, the permanent prestressed steel strands are inserted through the prestressed steel strand ducts and tensioned and grouted. Step S8: After the permanent prestressing tensioning is completed, the temporary prestressing devices and temporary support platforms are dismantled symmetrically in batches in sequence.

[0013] Furthermore, the vertical hinge is pre-embedded before the pier foundation and V-leg are poured. After the V-leg is vertically rotated into place, the concrete of the bottom section of the V-leg outside the vertical hinge area is poured first, and then the vertical hinge is removed and the concrete at its position is poured, or the vertical hinge is poured together as a force transmission structure.

[0014] Furthermore, the assembly method of the V-leg in step S3 is any one of the following: a. In-situ assembly: A support platform is erected at the pier foundation location, and the components are hoisted and assembled sequentially from bottom to top; b. Vertical rotation after low-level assembly: An assembly frame is erected at a low level corresponding to the pier foundation position. The prefabricated V-leg sections are spliced ​​into a whole. The V-leg is vertically rotated to the design position by the vertical rotation hinges pre-set in the pier foundation and at the bottom of the V-leg. Then, the post-cast section at the bottom of the V-leg is poured.

[0015] Furthermore, the main beam is assembled in step S6 in any of the following ways: a. Cantilever assembly using mobile suspended hoisting equipment; b. Erect a support platform and assemble the parts on the support platform.

[0016] Compared with existing technologies, this invention has the following advantages: By combining prefabrication and assembly technology with the design of an "inverted beam method" template, it overcomes the shortcomings of traditional cast-in-place construction of V-shaped rigid frame bridges, achieving rapid and standardized prefabrication of the V-shaped rigid frame bridge (variable cross-section) beam and (variable cross-section) V-legs. On-site, various methods can be combined for rapid assembly of the main beam (such as cantilever assembly) and V-legs (such as low-lying assembly followed by vertical rotation). Local nodes utilize post-cast wet connections, significantly shortening the construction cycle and effectively controlling construction quality and the impact on the surrounding environment. Especially for railway-related bridges, it greatly reduces interference with existing operating railways, and reduces corresponding construction coordination and costs. In summary, by using a prefabricated V-shaped rigid frame bridge and its construction method, the construction process of this complex structure is standardized and prefabricated, greatly shortening the construction period, reducing the risks of high-altitude operations and interference with existing traffic, and improving the quality and durability of the bridge through factory prefabrication, combining economic, convenient, and environmentally friendly advantages. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the rigid frame bridge of the present invention; Figure 2 This is a cross-sectional view of the rigid frame bridge of the present invention; Figure 3 This is a schematic diagram of the segmented rigid frame bridge structure of the present invention; Figure 4 This is a schematic diagram of the prefabricated segment structure of the main beam of the present invention; Figure 5 This is a schematic diagram of the inner and outer formwork and expansion joint structure when the variable cross-section main beam is prefabricated using the inverted beam method in this invention; Figure 6 This is a schematic diagram of the end formwork and expansion joint structure when the variable cross-section main beam is prefabricated using the inverted beam method in this invention; Figure 7 This is a schematic diagram of the V-leg of the present invention, which is constructed by vertical rotation after low-lying assembly. Figure 8 This is a schematic diagram of the V-leg of the present invention using the in-situ assembly construction method; Figure 9 This is a schematic diagram of the in-situ assembly process of the V-leg of the present invention. Figure 10 This is a schematic diagram of the cast-in-place connection between the V-leg and the No. 0 segment beam of the present invention; Figure 11This is a schematic diagram of the assembly of the V-leg, the precast segment 0 of the beam, and the cast-in-place segment 0 of the beam according to the present invention; Figure 12 This is a schematic diagram of the main beam assembly of the present invention.

[0018] In the diagram, 1. Pier foundation; 2. V-leg; 2-1. Precast V-leg segment; 2-2. Post-cast V-leg bottom segment; 2-3. Cast-in-place V-leg top segment; 3. Main beam; 4. Segment 0 beam; 4-1. Cast-in-place segment 0 beam; 4-2. Precast segment 0 beam; 5. Segment 1 beam; 6. Segment 2 beam; 7. Segment 3 beam; 8. Segment 4 beam; 9. Support platform; 10. Limiting block; 11. Shear key; 12. Prestressed steel strand duct; 13. Pre-tensioning device; 14. Vertical hinge; 15. Inner and outer formwork; 15-1. Outer formwork; 15-2. Inner formwork; 16. End formwork; 17. Vertical active expansion joint; 18. Lateral active expansion joint; 19. Passive expansion joint; 20. Isolation sleeve. Detailed Implementation Example 1

[0019] like Figures 1-4 As shown, the present invention provides a technical solution: a prefabricated V-shaped rigid frame bridge, comprising: Pier foundation 1; At least two V-legs 2, each V-leg 2 is composed of multiple precast V-leg sections 2-1 stacked along the height direction, the bottom of the V-leg 2 is fixed to the pier foundation 1 through the V-leg bottom post-cast section 2-2, and the top of the V-leg 2 is provided with a V-leg top cast-in-place section 2-3; The main beam 3 includes segment 0 beam 4 and multiple precast main beam segments symmetrically arranged on both sides of segment 0 beam 4 along the longitudinal direction. The multiple precast main beam segments include segment 1 beam 5, segment 2 beam 6, segment 3 beam 7, and segment 4 beam 8. The precast main beam segments are constructed using the "inverted beam method", which involves first constructing the top slab with a constant width, then constructing the web, and finally constructing the bottom slab. The V-leg 2 and the main beam 3 can be precast in the factory and transported to the site, or they can be precast on site.

[0020] The 0th segment beam 4 further includes a cast-in-place 0th segment beam 4-1 and at least one precast 0th segment beam 4-2. The cast-in-place 0th segment beam 4-1 and the cast-in-place V-leg top segment 2-3 are integrally cast to form a rigid connection node between the V-leg 2 and the main beam 3.

[0021] Among them, the cast-in-place segment 4-1 of segment 0, segment 5 of segment 1, segment 6 of segment 2, segment 7 of segment 3 and segment 8 of segment 4 are all composed of N precast segment beams with standardized lengths of 1 meter or 2 meters.

[0022] Shear keys 11 are provided on the splicing surfaces between the precast V-leg segments 2-1, between the precast segment 4-2 of segment 0 and the adjacent cast-in-place segment 4-1 of segment 0, and between the precast segments of each main beam. The shear keys 11 are mutually matching tenon and mortise structures. Adjacent segments are bonded together with structural adhesive and temporary pre-tightening force is applied by a temporary pre-tightening device 13. The pre-tightening device 13 can be parallel steel strands, parallel steel wires, or precision-rolled threaded steel bars, and the material can be metal cable or non-metal cable (basalt fiber). When the V-leg 2 and the main beam 3 are precast, if the tenons and mortises of the shear keys 11 of the front and rear segments cannot match, a concrete wet joint is used for connection.

[0023] The V-leg 2 and the main beam 3 are equipped with prestressed steel strand ducts 12 that run through the segments, which are used to insert and tension permanent prestressed steel strands after the segments are assembled; permanent prestress can be applied to the V-leg 2 according to the stress requirements.

[0024] Among them, the V-leg precast section 2-1 and the main beam precast segment are both standardized length modules of 1 meter or 2 meters.

[0025] like Figure 5 , Figure 6 As shown, the V-leg 2 and the main beam 3 are structures with equal or variable cross-sections. When the V-leg 2 and the main beam 3 are structures with variable cross-sections, their precast segments need to be matched with a variable cross-section formwork system. Taking a single-box double-cell variable cross-section box girder as an example, to ensure construction convenience, the precast segments of the main beam 3 are constructed using the "inverted beam method," that is, the construction method of first constructing the top slab with a constant width, then constructing the web, and finally constructing the bottom slab. The variable cross-section formwork system includes inner and outer formwork 15 and end formwork 16. The inner and outer formwork 15 includes outer formwork 15-1 and inner formwork 15-2. The inner and outer formwork 15 and the end formwork 16 are equipped with vertical active expansion joints 17 and horizontal active expansion joints 18. The template system includes a vertical active expansion joint 18 and a passive expansion joint 19. The expansion joints are adjusted to change the template dimensions, accommodating variations in beam height, bottom slab width, and web thickness. The changing sections of the expansion joints are enclosed by isolation sleeves 20. Specifically, when the cross-section of the main beam 3 changes, the beam segment height, bottom slab width, and thickness are adjusted by regulating the vertical active expansion joint 17 and passive expansion joint 19 on the inner and outer templates 15. The web thickness is adjusted by regulating the horizontal active expansion joint 18 on the inner template 15-2. The end template 16 ensures that the ends of all beam segments are closed during prefabrication, with the top, web, and bottom slab widths being the maximum values ​​for all three main beam segments. The end template 16 adjusts the beam segment height, bottom slab width, and thickness using the vertical active expansion joint 17 and passive expansion joint 19. All changing sections of the expansion joints in the template system are enclosed by isolation sleeves 20 to prevent concrete intrusion during beam segment prefabrication.

[0026] The V-leg bottom post-cast section 2-2 is a conventional reinforced concrete structure, a steel-reinforced concrete structure, or a UHPC structure; UHPC stands for Ultra-High Performance Concrete.

[0027] The connection structure between the bottom of the V-leg 2 and the pier foundation 1 can be any of the following: a. The V-leg bottom post-cast section 2-2 is a cast-in-place concrete structure; b. The first V-leg precast section 2-1 connected to the pier foundation 1 is directly connected to the pier foundation 1 through a grouting sleeve or socket connection structure, and the V-leg bottom post-cast section 2-2 is eliminated.

[0028] Wherein, the V-leg 2 is a solid pier or a box-type hollow thin-walled pier; the main beam 3 is a box beam; the V-leg 2 and the main beam 3 are reinforced concrete structures, steel structures, steel-concrete composite structures or steel-UHPC composite structures.

[0029] When the V-leg 2 and the main beam 3 are steel-concrete composite structures or steel-UHPC composite structures, they are composed of steel structures, concrete or UHPC structures, shear studs and stiffening ribs. The shear studs are channel steel, studs or PBL shear keys; the cross-sectional shape is box section, dumbbell section, H section, I-shaped section, king-shaped section or I-shaped section; the structural form is without grid or with grid.

[0030] If the V-leg 2 is assembled in a low-lying position and then rotated vertically during construction, such as... Figure 7 As shown, at this time, multiple vertical hinges 14 and limiting blocks 10 can be arranged in the transverse direction of the bridge at the pier foundation 1 position according to the stress requirements. After the V-leg 2 is vertically rotated into place and the limiting blocks 10 are removed, the concrete outside the area of ​​the vertical hinge 14 in the post-cast section 2-2 at the bottom of the V-leg can be poured first, then the vertical hinge 14 can be removed, and finally the concrete at the position of the vertical hinge 14 can be poured. Alternatively, the vertical hinge 14 can be poured together as a force transmission structure. Before pouring, the vertical hinge 14 is pre-embedded at fixed points in the V-leg 2 and the pier foundation 1. If the V-leg 2 adopts the in-situ assembly construction method, such as Figure 8 As shown, the support platform 9 is erected and hoisted from bottom to top using hoisting equipment. The support platform 9 can be a full-span scaffold, a steel pipe Bailey beam scaffold, or a false frame (Type 64 military beam combined with Type 83 military pier), etc. Before the V-leg 2, pier foundation 1 and No. 0 segment beam 4 are pre-embedded with steel bars at fixed points to facilitate the formation of an overall load-bearing structure.

[0031] The main beam 3 can be assembled using mobile suspended hoisting equipment, such as a bridge erecting machine, or it can be assembled using a support platform 9 combined with hoisting equipment, such as a full-span scaffold, a steel pipe Bailey beam scaffold, or a false frame (Type 64 military beam combined with Type 83 military pier). The hoisting equipment can be a bridge crane (beam crane, bridge crane, etc.), a boom crane (gantry crane, tower crane, etc.), or a lifting machine (guide rail lift, gear rail climbing device, etc.) combined with translation equipment.

[0032] When the precast main beam 3 segments are hoisted and assembled, if the safety clearance between the hoisting equipment and existing facilities (such as high-voltage lines) does not meet the specifications or regulations, a construction method of assembling at a low position and then jacking up to the design position can be adopted; or a construction method of parallel assembly and then jacking up to the design position can be adopted; furthermore, the above two construction methods can be combined to achieve the purpose.

[0033] The supporting platform 9 is a steel structure, welded together with the reinforcing bars of the pier foundation 1, and will be removed when the V-leg bottom post-cast section 2-2 is poured.

[0034] The shear keys 11 are evenly arranged on the splicing surface.

[0035] The prefabricated V-shaped rigid frame bridge construction method can be used for other types of V-piers, such as single piers (solid or hollow), double-limb thin-walled piers, Y-shaped (frame) piers, inverted Y-shaped frame piers, or portal frame piers; and for other types of bridges, such as continuous rigid frame bridges or V-shaped arch composite bridges.

[0036] This invention combines prefabrication and assembly technology to innovatively propose a prefabricated V-shaped rigid frame bridge, realizing the standardized and prefabricated construction of V-shaped rigid frame bridges, which has the advantages of economy, convenience and green environmental protection. Example 2

[0037] A construction method for a prefabricated V-shaped rigid frame bridge includes the following steps: Step S1: Prefabricate the V-leg prefabricated segment 2-1 and the main beam prefabricated segment in the factory or on site. During prefabrication, shear keys 11 are set on the segment splicing surface, and prestressed steel strand ducts 12 are pre-embedded. When prefabricating the variable cross-section main beam segment, the "inverted beam method" construction sequence is adopted for prefabrication, that is, the top slab is constructed first, then the web slab is constructed, and finally the bottom slab is constructed. A variable template system is used for forming. The variable template system changes the template size by adjusting the vertical active expansion device 17, the horizontal active expansion device 18 and the passive expansion device 19 to adapt to the changes in beam height, bottom slab width and web thickness. When using the "inverted beam method" to prefabricate the variable cross-section main beam segment in step S1, the top slab is constructed first, followed by the web slab, and finally the bottom slab. The template size is adjusted by an expansion joint, and the variable section of the expansion joint is sealed with an isolation sleeve 20 to prevent concrete intrusion. In step S1, the prefabricated segments are prefabricated using the short-line matching method, that is, after one segment is poured, it is used as the end face template for the next segment to ensure that the splicing surfaces of adjacent segments fit precisely.

[0038] Step S2: Construct the pier foundation 1 on site, and pre-install reinforcing bars or connecting structures on the pier foundation 1 to connect with the V-leg 2; Step S3: Assemble the V-leg 2. Hoist multiple prefabricated V-leg sections 2-1 from bottom to top, match and splice them using shear keys 11 and structural adhesive, and apply temporary pre-tightening force using temporary pre-tightening device 13 to form the V-leg structure. In step S3, the assembly method of V-leg 2 is any one of the following: a. In-situ assembly: A support platform 9 is erected at the pier foundation 1, and the components are hoisted and assembled sequentially from bottom to top; b. Vertical rotation after low-level assembly: Erect an assembly frame at a low level corresponding to the position of the pier foundation 1, and assemble the precast V-leg section 2-1 into a whole. Then, rotate the V-leg 2 vertically to the design position through the vertical rotation hinge 14 pre-set at the bottom of the pier foundation 1 and the V-leg 2, and then pour the post-cast section 2-2 at the bottom of the V-leg.

[0039] Step S4: Pour the post-cast section 2-2 at the bottom of the V-leg to solidify the bottom of the assembled V-leg 2 with the pier foundation 1; Step S5: Pour the cast-in-place section 2-3 of the V-leg top and the cast-in-place section 4-1 of segment 0 beam. Connect the top reinforcement of V-leg 2 on both sides to the reinforcement of cast-in-place section 4-1 of segment 0 beam. After setting up the formwork, pour the concrete in one go to form a rigid joint. Step S6: Assemble the main beam 3. With V-leg 2 and segment 0 beam 4 as the center, hoist the precast segment 4-2 of segment 0 beam and each precast segment of the main beam in sequence symmetrically to both sides. Match and splice them by shear key 11 and structural adhesive, and apply temporary pre-tightening force by temporary pre-tightening device 13. The main beam 3 is assembled in step S6 in any of the following ways: a. Cantilever assembly using mobile suspended hoisting equipment; b. Erect support platform 9 and assemble the components on support platform 9.

[0040] Step S7: After the segment splicing is completed, the permanent prestressed steel strands are inserted through the prestressed steel strand duct 12 and tensioned and grouted. Step S8: After the permanent prestressing tensioning is completed, the temporary pre-tensioning device 13 and the temporary support platform 9 are removed in batches in sequence and symmetrically.

[0041] The vertical hinge 14 is pre-embedded before the pier foundation 1 and V-leg 2 are poured. After the V-leg is vertically rotated into place, the concrete of the bottom section 2-2 of the V-leg outside the area of ​​the vertical hinge 14 is poured first, and then the vertical hinge 14 is removed and the concrete at its position is poured, or the vertical hinge 14 is poured together as a force transmission structure.

[0042] If the safety clearance between the hoisting equipment and existing facilities does not meet the requirements during the hoisting and assembly of the precast main beam segments, any of the following construction methods shall be adopted: a. After low-level assembly, it is then lifted to the designed position; b. After parallel assembly, push it to the designed position; c. Combine the two methods above.

[0043] It also includes a construction monitoring step after step S6, which includes real-time measurement of beam alignment, stress and temperature. Example 3

[0044] The following example, a V-shaped rigid frame bridge with a span of 2×70m, a main beam of single-box double-cell variable cross-section box girder, and V-leg 2 of solid equal-height rectangular cross-section, will be used to explain the construction method of the present invention in detail. Design and factory prefabrication; A three-dimensional digital model of the entire bridge was established using BIM technology, precisely dividing the V-leg 2 and main beam 3 into standard segment lengths. Taking into account component weight, transport vehicle limitations, the capabilities of commonly used on-site hoisting equipment, and the fitting accuracy of the curve segments, 1 meter was selected as the standard segment length for V-leg 2 and main beam 3, ensuring that the weight of a single segment is controlled within the range of 40-60 tons, allowing for hoisting using an 80-ton truck crane. In the BIM-based three-dimensional digital model of the entire bridge, each segment was uniquely numbered, and all details, including the internal reinforcing steel, prestressed steel strand ducts 12, shear keys 11, and hoisting holes, were precisely designed.

[0045] Based on the segment design dimensions, formwork with adjustable height and width is manufactured. A "short-line matching method" is used for prefabrication, meaning that after one segment (segment N) is poured, it is used as the end face formwork for the next segment (segment N+1), ensuring a perfect fit between adjacent segments and precise engagement of shear keys 11. When prefabricating variable cross-section main beam segments, a "reverse beam method" construction sequence is used: first construct the top slab, then the web, and finally the bottom slab. The formwork dimensions are adjusted using expansion joints on the variable formwork system, and the changing sections of the expansion joints are sealed with isolation sleeves 20 to prevent concrete intrusion.

[0046] Precast process: a. Reinforcing cage fabrication: In the rebar processing yard, automated equipment is used to fabricate segmental reinforcing cages, and pre-embed prestressed steel strand ducts 12, grouting holes, hoisting sleeves, etc. b. Formwork placement and pouring: The reinforcing cage is hoisted into the formwork, the end face template (i.e., the previous segment) is placed, and high-performance C60 concrete is poured. An attached vibrator is used during pouring to ensure concrete compaction. c. Curing: After the concrete is poured, steam curing or covering and moisturizing curing are carried out to ensure rapid and stable early strength development of the concrete. d. Demolding and transportation: After reaching the demolding strength, the formwork is removed, the newly fabricated segment is moved to the storage yard, and it is used as the end formwork for the next segment.

[0047] Substructure construction and preparation work; While the components are prefabricated in the factory, the cast-in-place construction of the pier foundation 1 is carried out simultaneously on site. After the pier foundation 1 is completed, the installation baseline and elevation control points of the V-leg 2 are accurately measured and marked according to the design drawings. At the same time, necessary temporary support platforms 9 are erected on both sides of the pier foundation 1 for auxiliary posture adjustment and temporary fixation during the assembly process of the V-leg 2.

[0048] Assembly of V-Leg 2; like Figure 9 As shown, this embodiment adopts an in-situ assembly method. A support platform 9 for assembling the V-leg 2 and main beam 3 is erected. The support frame must undergo rigorous calculations and pre-stressing measures are implemented to eliminate inelastic deformation. The first segment of V-leg 2 is precisely hoisted to the designed position at the top of the pier foundation 1. Sufficient length of lapped reinforcing bars are reserved at the bottom of this segment and at the top of the pier foundation 1. The reserved reinforcing bars of the precast V-leg segment 2-1 are reliably connected (welded) to the reserved reinforcing bars of the pier foundation 1. Formwork is erected around the connection area to form a closed post-cast area. High-strength, micro-expansion, non-shrinkage grout is poured into the post-cast area and thoroughly vibrated and cured. Using an 80-ton truck crane, the second segment is hoisted above the precast V-leg segment 2-1. Before hoisting, the splicing surface is cleaned to remove laitance and debris, ensuring the surface is dry. The two-component epoxy resin structural adhesive is accurately weighed and thoroughly mixed according to the product instructions. Apply the mixed structural adhesive evenly to the upper splicing surface of the precast V-leg segment 2-1, controlling the thickness to 2-3 mm. Slowly lower the bottom post-cast segment 2-2 of the V-leg, guiding it precisely with the precast V-leg segment 2-1 using the pre-set guide rods and shear keys 11 on the segment. Immediately insert temporary prestressed fine-rolled threaded steel bars, apply a certain tension, and press the two segments tightly together. Following the above steps, assemble all V-leg segments sequentially upwards until the design elevation is reached. For each segment assembled, precise measurement and adjustment of its planar position, elevation, and inclination are required.

[0049] Cast the post-cast section at the bottom of the V-shaped leg; After all segments of V-leg 2 are assembled and adjusted into place, the post-cast section 2-2 at the bottom of V-leg is poured. In this embodiment, C60 concrete is used for the post-cast section 2-2 at the bottom of V-leg. During pouring, it is necessary to ensure that the concrete is dense and forms a reliable connection with the precast section 2-1 of V-leg and the pier foundation 1.

[0050] The cast-in-place connection between V-leg 2 and segment 0 beam 4; like Figure 10 As shown, the pre-reserved reinforcing bars of the two V-leg top cast-in-place sections 2-3 are extended into the reinforcing cage of the cast-in-place section 4-1 of segment 0 beam and reliably lapped. The reinforcing bars and structural reinforcing mesh of the cast-in-place section 0 beam itself are tied. The side and bottom formwork of the cast-in-place section 4-1 of segment 0 beam are installed, and the longitudinal prestressed ducts penetrating segment 4-1 are precisely arranged. C60 concrete for segment 4-1 of segment 0 beam is poured in one go. During pouring, the slump of the concrete is strictly controlled, and the pouring is carried out in layers and symmetrically to ensure compaction, especially at the junction of the V-leg 2 reinforcing bars and the concrete of segment 4-1 of segment 0 beam. After pouring, strict curing is carried out. Once the concrete strength reaches the design requirements, the formwork and supports are removed.

[0051] Assembly of main beam 3; like Figure 11 As shown, first assemble the precast segment 4-2 of the No. 0 segment beam at the top of V-leg 2. After forming a complete V-shaped triangular area, symmetrically assemble segments at both ends of the cast-in-place segment 4-1 of the No. 0 segment beam. Figure 12 As shown, precast main beam segments are lifted from the ground or transport vehicles to the assembly position using hoisting equipment. The beams are spliced ​​using the same "shear key 11 + structural adhesive" process as the V-leg 2 segment assembly, and temporary prestress is applied. This process is repeated, gradually assembling the main beams symmetrically away from V-leg 2. Strict construction monitoring is implemented during construction, including real-time measurement of beam alignment, stress, and temperature, to ensure the structural condition matches the design expectations.

[0052] Prestressing tensioning; After each segment of the main beam is assembled, the permanent prestressed steel strands within that segment are threaded in and tensioned. After tensioning, grouting is performed promptly to protect the prestressing tendons and ensure they work together with the beam structure.

[0053] Dismantle temporary facilities; After each segment of the main beam is assembled, the permanent prestressed steel strands within that segment are threaded in and tensioned. After tensioning, grouting is performed promptly to protect the prestressing tendons and ensure they work together with the beam structure.

[0054] Dismantle temporary facilities; After all the precast beam segments of the last segment have been assembled and the permanent prestressed steel strands have been tensioned, the temporary prestressing device 13 and the support platform 9 are dismantled in batches in sequence and symmetrically.

[0055] Construction and final acceptance of ancillary works; Construction of ancillary works such as bridge deck paving, crash barriers, and expansion joints will be carried out. After the bridge is completed, static and dynamic load tests will be conducted in accordance with specifications to verify the actual load-bearing capacity and structural performance of the bridge.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fabricated V-type rigid frame bridge, characterized in that, The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same.

2. The prefabricated V-type rigid frame bridge according to claim 1, characterized in that: The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same.

3. The prefabricated V-type rigid frame bridge according to claim 2, characterized in that: The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same.

4. The prefabricated V-type rigid frame bridge according to claim 3, characterized in that: The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same.

5. The prefabricated V-type rigid frame bridge according to claim 4, characterized in that: The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same.

6. The prefabricated V-type rigid frame bridge according to claim 5, characterized in that: The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same.

7. A construction method for the assembled V-type rigid frame bridge according to any one of claims 1-6, characterized in that, The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and a method for constructing the same. The application relates to a prefabricated segmental structure of a bridge pier and Step S6: Assembling the main girder, taking the V-leg and No. 0 segment girder as the center, symmetrically hoisting the No. 0 segment girder prefabricated segment and each main girder prefabricated segment to both sides in sequence, matching and splicing through shear keys and structural glue, and applying temporary pre-tightening force by using temporary pre-tightening devices; Step S7: After the segment splicing is completed, the permanent prestressed steel strands are inserted through the prestressed steel strand pipes and tensioned and grouted; Step S8: After the permanent prestressed tensioning is completed, the temporary pre-tightening devices and the temporary support platform are symmetrically removed in sequence in batches.

8. The construction method of the assembled V-type rigid frame bridge according to claim 7, characterized in that: The vertical hinge is pre-buried before the pouring of the pier base and the V-leg, and after the V-leg is vertically turned to the position, the concrete of the V-leg bottom post-pouring segment outside the vertical hinge area is poured first, then the vertical hinge is removed and the concrete at the position of the vertical hinge is poured, or the vertical hinge is poured as a force transmission structure.

9. The construction method of the assembled V-type rigid frame bridge according to claim 7, characterized in that: The assembling mode of the V-leg in step S3 is any one of the following: a. In-situ assembly: a support platform is erected at the pier base position, and the V-leg prefabricated segments are hoisted and spliced in sequence from bottom to top; b. Low-position assembly and vertical turning: an assembly jig is erected at a low position corresponding to the pier base position, the V-leg prefabricated segments are spliced into a whole, the V-leg is vertically turned to the design position through the vertical hinge pre-set at the pier base and the V-leg bottom, and then the V-leg bottom post-pouring segment is poured.

10. The construction method of the assembled V-type rigid frame bridge according to claim 7, characterized in that: The assembling mode of the main girder in step S6 is any one of the following: a. Cantilever assembly by using a mobile suspended hoisting device; b. Erection of a support platform and assembly on the support platform.

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