An assembled UHPC rigid frame bridge and a construction method thereof

Abstract

The application relates to the technical field of bridge construction, and discloses an assembled UHPC rigid frame bridge and a construction method thereof, wherein the rigid frame bridge comprises multiple groups of bridge piers and a box girder arranged between the adjacent two groups of bridge piers; the box girder is assembled by a main girder and multiple groups of bridge floor panels; the multiple groups of bridge floor panels are arranged in sequence along the length direction of the main girder; first wet joints are reserved between the adjacent two groups of bridge floor panels; second wet joints are reserved between the corresponding docking bridge floor panels of the adjacent two-span box girders; and wet joint supporting plates extending outward are arranged at the two sides of the bottom of the prefabricated bridge floor panel corresponding to the first wet joints and the second wet joints; according to the application, the wet joint forms are differentiated according to the stress characteristics of the positive and negative bending moments of the box girder; the tooth-shaped joints are adopted in the negative bending moment sections of the box girder, and the flat joints are adopted in the positive bending moment sections; and cooperating with the optimized assembly and pouring sequence, the bridge floor panel cracking can be effectively controlled without arranging the post-tensioned prestressed steel strands in the negative bending moment sections of the middle pier top.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, specifically relating to a prefabricated UHPC rigid frame bridge and its construction method. Background Technology

[0002] Currently, urban small-span bridge projects generally adopt traditional precast concrete bridges, cast-in-place box girder bridges, and steel-concrete composite bridges. However, these types of bridges have many technical drawbacks in practical applications: for example, traditional concrete bridges have a large self-weight, redundant cross-sectional dimensions, and low structural lightweighting, making it difficult to meet the requirements of urban bridges for building height, traffic space, and landscape effects; while conventional precast assembled bridges mostly adopt whole-span precasting or simple segmented precasting, which makes them prone to cracking in the negative bending moment area, usually requiring a large number of post-tensioned prestressed steel strands, resulting in complex construction procedures, long cycles, large on-site formwork workload, and low assembly efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a rigid frame bridge with a simple structure and reasonable design in order to solve the above problems.

[0004] The present invention achieves the above objectives through the following technical solutions:

[0005] This invention provides a prefabricated UHPC rigid frame bridge, comprising multiple sets of piers and box girders erected between adjacent sets of piers. The box girder is assembled from a main beam and multiple sets of bridge decks. The multiple sets of bridge decks are arranged sequentially along the length of the main beam. A first wet joint is reserved between two adjacent sets of bridge decks, and a second wet joint is reserved between the bridge decks of two adjacent spans of box girders that are connected. The prefabricated bridge decks are provided with outwardly extending wet joint support plates on both sides of the bottom corresponding to the first and second wet joints. The joint shape of the first and second wet joints is set according to the stress characteristics of the box girder.

[0006] The bridge piers consist of a central pier and side piers located on both sides of the central pier. The box girder is fixed to the central pier by the first steel bar pre-reserved at the top of the central pier and cast in place. The bottom surface of the end of the main girder near the side pier is connected to the top of the side pier by seismic bearings.

[0007] As a further optimization of the present invention, the upper end face of the main beam is provided with third reinforcing bars at intervals along the length of the main beam, and shear holes corresponding to the third reinforcing bars are opened on the surface of multiple sets of bridge decks.

[0008] As a further optimization of the present invention, the section above the middle pier is the negative bending moment section of the box girder, the section of the box girder spanning two adjacent sets of piers is the positive bending moment section, the second wet joint is a toothed joint, the first wet joint located in the negative bending moment section is a toothed joint, and the first wet joint located in the positive bending moment section is a straight joint.

[0009] As a further optimization of the present invention, the bridge pier includes an upper pier and a lower pier. The top surface of the lower pier is provided with a lower reserved groove, and the bottom surface of the upper pier is provided with an upper reserved groove. The surface of the upper pier is provided with grouting holes and venting holes that communicate with the upper reserved groove. A supporting steel plate is connected to the bottom surface of the lower reserved groove, and the upper end surface of the supporting steel plate extends into the upper reserved groove and abuts against the inner top surface of the upper reserved groove.

[0010] As a further optimization of the present invention, the inner bottom surface of the lower reserved groove has an upward protrusion of a lower reinforcing block, and the inner top surface of the upper reserved groove has an downward protrusion of an upper reinforcing block. The surfaces of the upper and lower reinforcing blocks are both provided with grooves. The grooves have a dovetail-shaped cross-section and include longitudinal grooves and transverse grooves. Multiple sets of transverse grooves are provided and are arranged linearly along the length direction of the upper reinforcing block. The longitudinal grooves are arranged perpendicular to the transverse grooves, and the multiple sets of transverse grooves are connected through the longitudinal grooves.

[0011] As a further optimization of the present invention, the supporting steel plate includes a top connecting part, a bottom connecting part and multiple sets of supporting parts. The top connecting part is sleeved on the outside of the upper reinforcing block, and the bottom reinforcing block is sleeved on the outside of the bottom reinforcing block. The upper end of the supporting part is connected to the top connecting part, and the lower end of the supporting part is connected to the bottom connecting part. Multiple sets of supporting parts are arranged circumferentially along the outer side surface of the lower reinforcing block.

[0012] The supporting steel plate also includes an inner reinforcing part and an outer reinforcing part connected to the corresponding two sides of the supporting part, and both the inner reinforcing part and the outer reinforcing part are inclined.

[0013] A second aspect of the present invention provides a construction method for a prefabricated UHPC rigid frame bridge, used to realize the construction of the prefabricated UHPC rigid frame bridge described above, comprising the following steps:

[0014] S1. Based on the span, structural form and design parameters of the rigid frame bridge, establish the finite element model of the rigid frame bridge;

[0015] S2. Obtain the bending moment diagram of the rigid frame bridge under constant load through finite element calculation, and determine the stress control area of ​​the box girder near the middle pier based on the bending moment diagram.

[0016] S3. Based on the stress control area, divide the prefabricated sections of the bridge deck and the shape of the wet joints, and prefabricate the piers, main beams and bridge deck in the factory.

[0017] S4. Transport the prefabricated piers, main beams and bridge decks to the construction site and assemble the rigid frame bridge in the set sequence.

[0018] S5. Complete the cast-in-place wet joints and curing to form a rigid frame bridge.

[0019] As a further optimization of the present invention, the prefabricated sections and connection forms of the bridge deck are divided according to the stress control area. Specifically, the box girder can be divided into positive bending moment sections and negative bending moment sections according to the stress control area. The length and position of the prefabricated sections of the bridge deck are divided according to the sections. The bridge deck located in the positive bending moment section adopts a flat straight joint connection, and the bridge deck located in the negative bending moment section adopts a toothed joint connection.

[0020] As a further optimization of the present invention, prefabricated piers, main beams, and bridge decks are transported to the construction site and assembled in a predetermined sequence. Specifically, the piers and seismic bearings are installed first, followed by the installation of prefabricated bridge decks from both ends of the side piers towards the middle pier. Wet joints are then poured sequentially from both ends towards the mid-span, forming a simply supported box girder with the main beams. Finally, the wet joint at the top of the middle pier is poured, forming a rigid frame bridge. This construction sequence reduces the negative bending moment of the box girder at the middle pier, improving structural durability.

[0021] The beneficial effects of this invention are as follows: Based on the differentiated positive and negative bending moment stress characteristics of the box girder, this invention sets up wet joint forms, using toothed joints in the negative bending moment section and straight joints in the positive bending moment section. Combined with an optimized assembly and pouring sequence, it effectively controls bridge deck cracking without the need to install post-tensioned prestressed steel strands in the negative bending moment area at the top of the pier. Simultaneously, it eliminates the on-site prestressed steel tensioning process, effectively shortening the construction period occupied by grouting and its curing, and reducing the risk of common quality defects such as voids in the grouting ducts, further improving structural durability and engineering quality. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the first and second wet joint structures in Embodiment 1 of the present invention;

[0024] Figure 3 This is a schematic diagram of the box girder structure according to Embodiment 1 of the present invention;

[0025] Figure 4 This is a schematic diagram of the internal structure of the lower pier in Embodiment 2 of the present invention;

[0026] Figure 5 This is a schematic diagram of the internal structure of the upper pier in Embodiment 2 of the present invention;

[0027] Figure 6 This is a schematic diagram of the connection between the upper pier and the lower pier in Embodiment 2 of the present invention;

[0028] Figure 7 This is a schematic diagram of the groove structure in Embodiment 2 of the present invention;

[0029] Figure 8This is a schematic diagram of the supporting steel plate structure according to Embodiment 2 of the present invention;

[0030] Figure 9 This is a finite element model diagram of the rigid frame bridge according to Embodiment 3 of the present invention;

[0031] Figure 10 This is the bending moment diagram of the rigid frame bridge in Embodiment 3 of the present invention.

[0032] In the diagram: 1. Main beam; 2. Bridge deck; 3. First wet joint; 4. Second wet joint; 5. Pier; 51. Upper pier; 52. Lower pier; 6. Seismic bearing; 7. Supporting steel plate; 71. Top connection; 72. Bottom connection; 73. Support; 74. Inner reinforcement; 75. Outer reinforcement; 8. Upper reserved groove; 9. Lower reserved groove; 10. Upper reinforcing block; 11. Lower reinforcing block; 12. Groove; 13. Shear hole. Detailed Implementation

[0033] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0034] Example 1;

[0035] refer to Figures 1 to 3 The structure shown is a prefabricated UHPC rigid frame bridge, including multiple sets of piers 5 and box girders erected between two adjacent sets of piers 5. The box girder is assembled from a main beam 1 and multiple sets of bridge deck 2. The multiple sets of bridge deck 2 are arranged sequentially along the length of the main beam 1. A first wet joint 3 is reserved between two adjacent sets of bridge deck 2. A second wet joint 4 is reserved between the bridge deck 2 that are connected to each other in two adjacent spans of box girder. The bottom of the prefabricated bridge deck 2 on both sides corresponding to the first wet joint 3 and the second wet joint 4 is provided with outwardly protruding wet joint support plates. The joint shape of the first wet joint 3 and the second wet joint 4 is set according to the stress characteristics of the box girder.

[0036] The multiple sets of piers 5 consist of a central pier and side piers located on both sides of the central pier. The box girder is fixed to the central pier by the first steel bar pre-reserved at the top of the central pier and cast in place. The bottom surface of the end of the main beam 1 near the side pier is connected to the top of the side pier by the seismic support 6.

[0037] Among them, the central pier and the main beam 1 are consolidated by pouring UHPC concrete. The top of the pier 5 is used as the bottom formwork. Before pouring, only the side formwork of the consolidation area needs to be installed. The rigid frame bridge is also equipped with stairways on both sides. The two sets of stairways are located at the ends of the two sets of box girders that are far apart from each other. The upper ends of the two sets of stairways are connected to the corresponding box girders.

[0038] It should be noted that all the piers 5, main beams 1, bridge decks 2, and stairways in this embodiment are prefabricated in the factory and assembled on the construction site. The main beam 1 is a U-beam, the piers 5 are solid, and each group of piers 5 is connected to the pile foundation through a cast-in-place foundation via a second steel bar reserved at the bottom of the pier. The middle pier is fixed to the main beam 1 via a first steel bar reserved at the top of the pier, and the side piers are connected to the main beam 1 via seismic bearings 6. The first and second steel bars are both vertically arranged.

[0039] Furthermore, the upper end face of the main beam 1 is provided with third reinforcing bars at intervals along the length of the main beam 1, and the surfaces of multiple sets of bridge deck 2 are provided with shear holes 13 corresponding to the third reinforcing bars.

[0040] Specifically, the bridge deck 2 is connected to the third steel bar at a certain distance from the top of the U-beam through the reserved shear holes 13. The corresponding two sides of the adjacent U-beams are pre-embedded with the fourth steel bar arranged horizontally. The two sets of bridge deck 2 closest to the middle pier and the steel bars of the two adjacent sets of U-beams and the middle pier are solidified together by cast-in-place.

[0041] It should be noted that the transverse reinforcing bars of adjacent bridge deck 2 (i.e., the fourth reinforcing bars pre-embedded on the corresponding surface of adjacent bridge deck 2) have been staggered and optimized while meeting the lap length requirements of the specifications, thereby improving the assembly efficiency of on-site installation; the thickness of the wet joint bearing plate at the bottom of the wet joint between adjacent bridge deck 2 (including the first wet joint 3 and the second wet joint 4) is 1.5cm, and the wet joint bearing plate is prefabricated in the factory. This setting avoids the need to set bottom formwork and side formwork at the joint; the bridge deck 2 passes through the reserved shear holes 13 is connected to the third steel bar reserved in the U-beam, and the top surface of the U-beam is used as the bottom formwork, so no additional formwork is required during pouring. In addition, in this embodiment, the installation sequence of bridge deck 2, the pouring sequence of wet joints and the type of wet joints have been optimized. Specifically, the precast bridge deck 2 needs to be installed sequentially from both ends of the side pier to the middle pier, and the wet joints need to be poured sequentially from both ends to the middle of the span, so that the wet joint near the top of the middle pier (the second wet joint 4) is poured last, thereby successfully controlling the cracking problem of bridge deck 2 in this area without prestress.

[0042] Furthermore, the section above the central pier is the negative bending moment section of the box girder, the section of the box girder spanning the two adjacent sets of piers 5 is the positive bending moment section, the second wet joint 4 is a toothed joint, the first wet joint 3 located in the negative bending moment section is a toothed joint, and the first wet joint 3 located in the positive bending moment section is a straight joint.

[0043] Among them, the toothed joint can be a comb-tooth joint or a dovetail joint; the wet joint support plate is a thin plate prefabricated at the bottom of the wet joint, which is used as a template later, so that no template needs to be installed on site when the wet joint is cast in place.

[0044] In this embodiment, the concrete used to construct pier 5, box girder, and stairway is UHPC. The fully prefabricated UHPC rigid frame bridge in this embodiment can be applied to small and medium span bridge projects in urban road networks, including simply supported variable rigid frame composite box girder bridges, continuous beam bridges, and pedestrian overpasses and landscape bridges that require lightweight design. This invention has unique advantages in urban expressways and viaducts where there are high requirements for structural lightweighting, construction progress, under-bridge traffic, and durability. It is particularly suitable for bridge engineering applications in coastal, humid, and other corrosive environments. Its high strength characteristics (≥120MPa) make it perform well in bridge reconstruction and expansion projects with limited space and high load-bearing requirements.

[0045] It should be noted that the fully prefabricated assembled box girder bridge structure suitable for UHPC materials proposed in this invention adopts a simply supported variable rigid frame design, avoiding the traditional prestressing arrangement in the negative bending moment zone, and achieving a synergistic improvement in structural stiffness and durability. Under the same span length (e.g., 30m), compared with conventional small box girder sections and conventional cast-in-place box girder sections, the cross-sectional height, web plate, and top and bottom plate thickness of the UHPC bridge of this invention are significantly reduced, thereby reducing the self-weight of the bridge with the same span and width by about 30% and 70%, respectively. Compared with UHPC prefabricated assembled T-beam bridges with the same span, the natural frequency structure of the rigid frame bridge of the combined box girder in this embodiment is increased by about 20%. In addition, compared with steel structure bridges, the UHPC rigid frame bridge of this embodiment also has significant advantages in construction cost, durability, and maintenance-free operation.

[0046] Example 2;

[0047] refer to Figures 4 to 6 The structure shown in this embodiment provides a prefabricated UHPC rigid frame bridge, which is a further improvement on the first embodiment. The pier 5 is designed as a multi-segment structure, which facilitates the transportation of the pier 5.

[0048] Specifically, pier 5 includes an upper pier section 51 and a lower pier section 52, which are assembled together. The upper pier section 51 is mainly used to support the main beam 1 and the seismic bearing 6, and to transfer the load of the superstructure. The lower pier section 52 is mainly used to connect the abutment and the pile foundation, and to transfer the load of the superstructure to the foundation. The segmented design can significantly reduce the weight and size of a single pier section and is compatible with conventional transport vehicles and hoisting equipment.

[0049] In this embodiment, the top surface of the upper pier portion 51 of the middle pier is cast-in-place and fixed to the main beam 1 by the first reinforcing bar, and the top surface of the upper pier portion 51 of the side pier is connected to the corresponding seismic support 6.

[0050] Furthermore, a lower reserved groove 9 is provided on the top surface of the lower pier 52, an upper reserved groove 8 is provided on the bottom surface of the upper pier 51, and grouting holes and venting holes communicating with the upper reserved groove 8 are provided on the surface of the upper pier 51. A supporting steel plate 7 is connected to the bottom surface of the lower reserved groove 9, and the upper end surface of the supporting steel plate 7 extends into the upper reserved groove 8 and abuts against the inner top surface of the upper reserved groove 8.

[0051] Among them, the grouting holes are used to inject UHPC grout into the pre-reserved grooves 8 and 9 to connect the lower pier 52 and the upper pier 51. The venting holes are used to expel air from the grooves to ensure the density of the grouting and improve the integrity and strength of the assembly nodes. The supporting steel plate 7 bears the vertical load of the upper pier 51, provides temporary support and vertical bearing capacity, and prevents local pressure damage to the pier body 5 during assembly.

[0052] It should be noted that the top surface of the lower pier 52 is pre-embedded with the fifth reinforcing bar, which is set along the periphery of the supporting steel plate 7. The supporting steel plate is made of low alloy high strength structural steel, carbon structural steel, high performance structural steel, etc. When used in combination with UHPC grouting material, the surface of the steel can be roughened and treated to resist slippage in order to enhance the interlocking force.

[0053] refer to Figure 6 and Figure 7 As shown in the partial structure, the lower reserved groove 9 has a lower reinforcing block 11 protruding upward from the inner bottom surface, and the upper reserved groove 8 has an upper reinforcing block 10 protruding downward from the inner top surface. The surfaces of the upper reinforcing block 10 and the lower reinforcing block 11 are both provided with grooves 12. The grooves 12 have a dovetail-shaped cross section and include a longitudinal groove and a transverse groove. The transverse grooves are provided in multiple sets and are arranged linearly along the length direction of the upper reinforcing block 10. The longitudinal grooves are arranged perpendicular to the transverse grooves, and the multiple sets of transverse grooves are connected through the longitudinal grooves.

[0054] Among them, the dovetail-shaped groove 12 can increase the contact area and interlocking force with the grout, and improve the shear and tensile strength of the assembled node; the crisscrossing grooves 12 can allow the grout to be fully filled, forming an interlocking structure, further strengthening the reliability of the node connection.

[0055] It should be noted that the upper reinforcing block 10 and the lower reinforcing block 11 do not contact each other, but are left with a certain gap for the injection of grout, so that the connection between the upper reinforcing block 10 and the lower reinforcing block 11 is more secure.

[0056] refer to Figure 6 and Figure 8 The structure shown includes a top connecting part 71, a bottom connecting part 72, and multiple sets of supporting parts 73. The top connecting part 71 is sleeved on the outside of the upper reinforcing block 10, and the bottom reinforcing block is sleeved on the outside of the bottom reinforcing block. The upper end of the supporting part 73 is connected to the top connecting part 71, and the lower end of the supporting part 73 is connected to the bottom connecting part 72. Multiple sets of supporting parts 73 are arranged circumferentially along the outer side surface of the lower reinforcing block 11.

[0057] The supporting steel plate 7 also includes an inner reinforcing part 74 and an outer reinforcing part 75 connected to the corresponding two sides of the supporting part 73. Both the inner reinforcing part 74 and the outer reinforcing part 75 are inclined.

[0058] It should be noted that the bottom connection part 72 of the supporting steel plate 7 is pre-embedded inside the pier 52 during construction; the circumferentially arranged supporting parts 73 form a ring support system to ensure the vertical stiffness and stability of the supporting steel plate 7.

[0059] It should be further explained that both the inner reinforcing part 74 and the outer reinforcing part 75 are inclined. The inner reinforcing part 74 is inclined downward from the inside of the support part 73 towards the center of the support steel plate 7, while the outer reinforcing part 75 is inclined upward from the outside of the support part 73 away from the center of the support steel plate 7. This structural design significantly improves the vertical stiffness and lateral force resistance of the support steel plate 7. The inclined surface can evenly transmit the shear force, bending moment, and vertical pressure of the pier joint to the support part 73 and the upper and lower connecting parts, disperse the stress in the upper and lower reserved groove areas, and prevent the pier 5 from cracking and crushing. In addition, the inclined structure can increase the contact area and interlocking force between the support steel plate 7 and the UHPC grouting material, forming a mechanical interlock, which greatly improves the shear resistance, tensile strength, and overall stress performance of the assembled joint, further enhances the energy dissipation capacity and integrity of the joint, and makes the segmented prefabricated pier 5 safer and more reliable under loads such as earthquakes.

[0060] Example 3;

[0061] like Figure 9 and Figure 10 As shown, this embodiment provides a construction method for a prefabricated UHPC rigid frame bridge, used to realize the construction of a prefabricated UHPC rigid frame bridge as described in Embodiment 1, including the following steps:

[0062] S1. Based on the span, structural form and design parameters of the rigid frame bridge, establish the finite element model of the rigid frame bridge;

[0063] S2. Obtain the bending moment diagram of the rigid frame bridge under constant load through finite element calculation, and determine the stress control area of ​​the box girder near the middle pier based on the bending moment diagram.

[0064] S3. Based on the stress control area, divide the prefabricated sections of the bridge deck and the shape of the wet joints, and prefabricate the piers, main beams and bridge deck in the factory.

[0065] S4. Transport the prefabricated piers, main beams and bridge decks to the construction site and assemble the rigid frame bridge in the set sequence.

[0066] S5. Complete the cast-in-place wet joints and curing to form a rigid frame bridge.

[0067] In this embodiment, the main beam 1 is prefabricated in two sections. The end of the main beam 1 closest to the middle pier extends 10cm into the middle pier. Specifically, through finite element calculation, the 10cm position on both sides of the middle pier is used as the support for the prefabricated U-beam, realizing the installation technology of the main beam 1 without scaffolding. This fully utilizes the high strength advantage of UHPC material, while ensuring the precise connection between the prefabricated pier 5 and the main beam 1, meeting the safety requirements for the subsequent prefabricated beam erection, so that the structure of pier 5 will not crack or overturn during the installation process.

[0068] Furthermore, based on the stress control area, the prefabricated sections and connection methods of bridge deck 2 are divided. Specifically, based on the stress control area, the box girder can be divided into positive bending moment sections and negative bending moment sections. The length and position of the prefabricated sections of bridge deck 2 are divided according to the sections. Bridge deck 2 located in the positive bending moment section adopts a flat straight joint connection, while bridge deck 2 located in the negative bending moment section adopts a toothed joint connection.

[0069] It should be noted that the construction method implemented in this way optimizes the joint form and pouring sequence, thereby eliminating the need for post-tensioned prestressed steel strands in the negative bending moment zone at the pier top and controlling cracking.

[0070] Furthermore, the prefabricated piers 5, main beams 1, and bridge deck 2 are transported to the construction site and assembled in the set sequence. Specifically, the piers 5 and seismic bearings 6 are installed first, and then the prefabricated bridge deck 2 is installed sequentially from both ends of the side piers to the middle pier. Wet joints are poured sequentially from both ends to the middle of the span so that the bridge deck 2 and the main beam 1 form a simply supported box girder. Finally, the wet joint at the top of the middle pier is poured to form a rigid frame bridge.

[0071] It should be noted that the UHPC rigid frame bridge constructed using this method effectively improves the overall stiffness and natural frequency of the structure. This UHPC rigid frame bridge eliminates the need for post-tensioned prestressed steel strands in the negative bending moment section at the top of pier 5. By optimizing the installation sequence of bridge deck 2, the pouring sequence of wet joints, and the type of wet joints, this construction sequence reduces the negative bending moment of the box girder at the middle pier. Cracking in this area without prestressing was successfully controlled. Simultaneously, eliminating the on-site prestressed steel tensioning process effectively shortens the construction period occupied by grouting and its curing, reduces the risk of common quality defects such as voids in the grouting ducts, and further improves structural durability and project quality.

[0072] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A prefabricated UHPC rigid frame bridge, characterized in that, The bridge includes multiple sets of piers and box girders erected between two adjacent sets of piers. The box girder is assembled from a main beam and multiple sets of bridge decks. The multiple sets of bridge decks are arranged sequentially along the length of the main beam. A first wet joint is reserved between two adjacent sets of bridge decks, and a second wet joint is reserved between the bridge decks that are connected to each other in two adjacent spans of box girders. The precast bridge decks are provided with outwardly protruding wet joint support plates on both sides of the bottom corresponding to the first and second wet joints. The joint shape of the first and second wet joints is set according to the stress characteristics of the box girder. The bridge piers consist of a central pier and side piers located on both sides of the central pier. The box girder is fixed to the central pier by the first steel bar pre-reserved at the top of the central pier and cast in place. The bottom surface of the end of the main girder near the side pier is connected to the top of the side pier by seismic bearings.

2. The prefabricated UHPC rigid frame bridge according to claim 1, characterized in that: The upper end face of the main beam is provided with third reinforcing bars at intervals along the length of the main beam, and shear holes corresponding to the third reinforcing bars are opened on the surface of multiple sets of bridge decks.

3. The prefabricated UHPC rigid frame bridge according to claim 1, characterized in that: The section above the central pier is the negative bending moment section of the box girder, the section of the box girder spanning two adjacent sets of piers is the positive bending moment section, the second wet joint is a toothed joint, the first wet joint located in the negative bending moment section is a toothed joint, and the first wet joint located in the positive bending moment section is a straight joint.

4. The prefabricated UHPC rigid frame bridge according to claim 1, characterized in that: The bridge pier includes an upper pier and a lower pier. The top surface of the lower pier has a lower reserved groove, and the bottom surface of the upper pier has an upper reserved groove. The surface of the upper pier has grouting holes and venting holes that communicate with the upper reserved groove. The bottom surface of the lower reserved groove is connected to a supporting steel plate, and the upper end of the supporting steel plate extends into the upper reserved groove and abuts against the inner top surface of the upper reserved groove.

5. A prefabricated UHPC rigid frame bridge according to claim 4, characterized in that: The lower reserved groove has a lower reinforcing block protruding upward from its inner bottom surface, and the upper reserved groove has an upper reinforcing block protruding downward from its inner top surface. Both the upper and lower reinforcing blocks have grooves on their surfaces. The grooves have a dovetail-shaped cross-section and include a longitudinal groove and a transverse groove. The transverse grooves are arranged in multiple sets and are linearly arranged along the length of the upper reinforcing block. The longitudinal grooves are perpendicular to the transverse grooves, and the multiple transverse grooves are connected through the longitudinal grooves.

6. A prefabricated UHPC rigid frame bridge according to claim 5, characterized in that: The supporting steel plate includes a top connecting part, a bottom connecting part, and multiple sets of supporting parts. The top connecting part is sleeved on the outside of the upper reinforcing block, and the bottom reinforcing block is sleeved on the outside of the bottom reinforcing block. The upper end of the supporting part is connected to the top connecting part, and the lower end of the supporting part is connected to the bottom connecting part. Multiple sets of supporting parts are arranged circumferentially along the outer side of the lower reinforcing block. The supporting steel plate also includes an inner reinforcing part and an outer reinforcing part connected to the corresponding two sides of the supporting part, and both the inner reinforcing part and the outer reinforcing part are inclined.

7. A construction method for a prefabricated UHPC rigid frame bridge, used to realize the construction of the prefabricated UHPC rigid frame bridge as described in claim 3, characterized in that, Includes the following steps: S1. Based on the span, structural form and design parameters of the rigid frame bridge, establish the finite element model of the rigid frame bridge; S2. Obtain the bending moment diagram of the rigid frame bridge under constant load through finite element calculation, and determine the stress control area of ​​the box girder near the middle pier based on the bending moment diagram. S3. Based on the stress control area, divide the prefabricated sections of the bridge deck and the shape of the wet joints, and prefabricate the piers, main beams and bridge deck in the factory. S4. Transport the prefabricated piers, main beams and bridge decks to the construction site and assemble the rigid frame bridge in the set sequence. S5. Complete the cast-in-place wet joints and curing to form a rigid frame bridge.

8. The construction method of a prefabricated UHPC rigid frame bridge according to claim 1, characterized in that: Based on the stress control area, the prefabricated sections and connection methods of the bridge deck are divided. Specifically, based on the stress control area, the box girder can be divided into positive bending moment sections and negative bending moment sections. The length and position of the prefabricated sections of the bridge deck are divided according to the sections. The bridge deck located in the positive bending moment section adopts a flat straight joint connection, and the bridge deck located in the negative bending moment section adopts a toothed joint connection.

9. The construction method of a prefabricated UHPC rigid frame bridge according to claim 1, characterized in that: The prefabricated piers, main beams, and bridge decks are transported to the construction site and assembled in a predetermined sequence. Specifically, the piers and seismic bearings are installed first, then the prefabricated bridge decks are installed sequentially from both ends of the side piers to the middle pier. Wet joints are poured sequentially from both ends to the middle of the span to form a simply supported box girder with the main beam. Finally, the wet joint at the top of the middle pier is poured to form a rigid frame bridge.

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