Prefabricated double-u-shaped uhcp main beam structure and reconstruction method thereof, and repair and recycling method of bridge main beam

Abstract

The application discloses an assembled double-U-shaped UHPC main beam structure, which comprises an outer U-shaped UHPC beam and an inner U-shaped UHPC beam, the inner U-shaped UHPC beam is inlaid in the inner cavity of the outer U-shaped UHPC beam, and a connecting assembly for detachably and fixedly connecting the outer U-shaped UHPC beam and the inner U-shaped UHPC beam is arranged between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam. The application further provides a reconstruction method of the above-mentioned assembled double-U-shaped UHPC main beam structure, a maintenance method of a bridge main beam and a recycling method of the bridge main beam. The double-U-shaped UHPC main beam structure is easy to realize recycling of the main beam structure, the bearing capacity is adjustable, and the economic benefit and environmental protection value of the UHPC are improved through recycling.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of bridges, and particularly relates to a main girder structure and a construction method thereof, and a maintenance and recycling method of a bridge main girder. BACKGROUND

[0002] When a bridge in service reaches the design service life or the actual bearing capacity cannot meet the requirements, the bridge in service often needs to be demolished. If direct blasting demolition is selected, a large amount of building materials will be wasted and the ecological environment will be greatly negatively affected. If the main girder of the bridge can be disassembled and reused, the problems of material waste and negative ecological impact can be reduced. In existing structures, ordinary concrete main girders, as important load-bearing components, generally work as a whole, and it is difficult to disassemble them partially. The mechanical properties of the disassembled ordinary concrete main girders will also be significantly reduced.

[0003] In recent years, due to the development and optimization of concrete materials, an ultra-high performance concrete (hereinafter referred to as UHPC) with excellent mechanical properties has been produced in engineering. Compared with traditional concrete materials, UHPC has ultra-high compressive strength, tensile strength and durability, and can effectively reduce the self-weight of the bridge and prolong the service life when used in bridge engineering. When the bridge reaches the design service life or the actual bearing capacity cannot meet the requirements, the bearing capacity of the main girder constructed by UHPC does not significantly degrade, and the main girder can be disassembled for secondary or multiple use.

[0004] However, the segments of the UHPC main girder in the prior art are generally cast in one body, the application scenarios for its reuse are limited, the reuse performance is not good, and the bearing capacity is difficult to control. In view of the above problems, a UHPC main girder structure with adjustable bearing capacity and easy recycling is proposed, which can significantly improve the economic benefit and improve the ecological effect. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the background, and to provide an assembled double-U type UHPC main girder structure and a reconstruction method thereof, and a maintenance and recycling method of a bridge main girder. The double-U type UHPC main girder structure is easy to realize the recycling of the main girder structure, the bearing capacity is adjustable, and the economic benefit and environmental value of UHPC are improved through recycling. To solve the above technical problems, the technical solution proposed by the present application is as follows:

[0006] An assembled double-U type UHPC main girder structure, comprising an outer U-shaped UHPC beam and an inner U-shaped UHPC beam, the inner U-shaped UHPC beam is embedded in the inner cavity of the outer U-shaped UHPC beam, and a connecting assembly for detachable fixed connection between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam is arranged between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam.

[0007] Preferably, in the prefabricated double-U-shaped UHPC main beam structure, the connecting assembly comprises a key-tooth type connecting structure arranged between the bottom surface of the inner cavity of the outer U-shaped UHPC beam and the bottom surface of the outer wall of the inner U-shaped UHPC beam.

[0008] Preferably, in the prefabricated double-U-shaped UHPC main beam structure, the key-tooth type connecting structure comprises a plurality of key-tooth type protrusions arranged on the bottom surface of the inner cavity of the outer U-shaped UHPC beam and a plurality of key-tooth type grooves arranged on the bottom surface of the outer wall of the inner U-shaped UHPC beam, and the key-tooth type protrusions and the key-tooth type grooves are matched with each other.

[0009] Preferably, in the prefabricated double-U-shaped UHPC main beam structure, the key-tooth type protrusions are arranged on the bottom surface of the inner cavity of the outer U-shaped UHPC beam in the transverse bridge direction, and the cross section of the key-tooth type protrusion is a trapezoidal shape with a narrow upper part and a wide lower part. The key-tooth type protrusions are arranged in the transverse bridge direction and have a trapezoidal shape, which can limit the relative movement between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam in the longitudinal bridge direction, and is conducive to ensuring the assembly and construction of the key-tooth type protrusions and the key-tooth type grooves.

[0010] By controlling the position of the contact surface of the key-tooth type protrusion and the key-tooth type groove, the bottom plate of the outer U-shaped UHPC beam is ensured to have only protrusions without grooves, so that the bending bearing capacity of the structure is not weakened due to the existence of the grooves. At this time, the key teeth of the key-tooth type protrusion can be protected by the web of the U-shaped cross section, and will not be damaged by impact or wear during transportation and construction. By controlling the position of the contact surface of the key-tooth type protrusion and the key-tooth type groove, the key-tooth type groove of the inner U-shaped UHPC beam is ensured to be recessed in the bottom plate, which can prevent the key-tooth type groove of the inner U-shaped UHPC beam from being damaged by impact or wear during transportation and construction.

[0011] Preferably, in the prefabricated double-U-shaped UHPC main beam structure, the connecting assembly comprises a key-tooth type connecting structure arranged between the bottom surface of the inner cavity of the outer U-shaped UHPC beam and the bottom surface of the outer wall of the inner U-shaped UHPC beam.

[0012] Preferably, in the prefabricated double-U-shaped UHPC main beam structure, the key-tooth type connecting structure comprises a plurality of first mortises arranged on the inner side top of the web of the outer U-shaped UHPC beam, a plurality of second mortises arranged on the outer side top of the web of the inner U-shaped UHPC beam, and a plurality of tenon assemblies, the first mortises and the second mortises correspond one by one, and the tenon assembly is a dumbbell-shaped bidirectional tenon which can be detachably clamped in the first mortise at one end and can be detachably clamped in the second mortise at the other end.

[0013] The dumbbell-shaped bidirectional tenon is divided into a left side, a middle part and a right side, the sizes and shapes of the left side and the right side should match the first mortise and the second mortise, and the length of the middle part is adapted to the transverse distance between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam. The tenon assembly is clamped in the first mortise and the second mortise, which can be used to limit the sliding of the outer U-shaped UHPC beam and the inner U-shaped UHPC beam between the longitudinal direction and the transverse direction of the bridge, facilitating disassembly and assembly.

[0014] As a general technical concept, the application also provides a reconstruction method of the prefabricated double-U-shaped UHPC main beam structure.

[0015] (1) The main beam of the bridge to be removed is cut to be deconstructed into main beam segments; the main beam of the bridge is a single-U-shaped UHPC main beam;

[0016] (2) The main beam segments obtained by deconstruction are maintained and detected, and the main beam segments with qualified physical and mechanical indexes are selected and stored for standby use;

[0017] (3) The main beam segments with sizes and mechanical indexes meeting the requirements are selected for standby use according to the design requirements of the main beam of the newly-built bridge;

[0018] (4) The main beam segments selected in step (3) are processed to form an outer U-shaped UHPC beam and an inner U-shaped UHPC beam connectable through the connecting assembly, and the outer U-shaped UHPC beam and the inner U-shaped UHPC beam are connected through the connecting assembly, thereby obtaining the prefabricated double-U-shaped UHPC main beam structure.

[0019] Specifically, the reconstruction method of the prefabricated double-U-shaped UHPC main beam structure includes the following steps:

[0020] (1) For the single-U-shaped UHPC main beam bridge to be deconstructed, a disc saw and a rope saw are used to cut the UHPC main beam by a static cutting method, so that the UHPC main beam is deconstructed into main beam segments convenient for transportation and storage;

[0021] (2) The separated main beam segments are transferred by means of temporary supports or bridge erection machines used in the static cutting process, and are transported to a factory or a target site by ships and vehicles;

[0022] (3) The disassembled main beam segments are maintained and detected, and the parts with qualified physical and mechanical indexes are selected and stored for standby use; in the application, multiple single-U-shaped UHPC main beam bridges can be disassembled to obtain multiple single-U-shaped UHPC main beams with different sizes and mechanical properties, and the selection can be made according to needs;

[0023] (4) according to the design requirements of the main beam of the newly built bridge, the size and mechanical indicators of the main beam section (used as the outer U-shaped UHPC beam and the inner U-shaped UHPC beam respectively) meeting the requirements are selected, and the main beam section is processed, the appropriate mortise and tenon groove is cut at the web of the main beam, and the corresponding key tooth type groove and key tooth type protrusion are processed at the bottom plate of the main beam;

[0024] (5) the size of the dumbbell-shaped bidirectional tenon is designed according to the cut-out mortise and tenon groove, and the pouring and curing of the dumbbell-shaped bidirectional tenon are completed;

[0025] (6) the splicing processing of the U-shaped main beam is performed, and the new assembled double U-shaped UHPC main beam structure is adjusted to meet the construction requirements and the structure checking requirements.

[0026] The outer U-shaped UHPC beam and the inner U-shaped UHPC beam of the assembled double U-shaped UHPC main beam structure can be obtained from the single U-shaped UHPC main beam obtained by disassembling the traditional old bridge, and the recycling rate of the main beam of the old bridge can be improved.

[0027] As a general technical concept, the application further provides a bridge main beam maintenance method, comprising the following steps:

[0028] (1) cutting the main beam section to be maintained of the bridge; the main beam section to be maintained is the assembled double U-shaped UHPC main beam structure;

[0029] (2) the outer U-shaped UHPC beam and the inner U-shaped UHPC beam obtained by disassembling the main beam section to be maintained;

[0030] (3) replacing the damaged outer U-shaped UHPC beam and / or inner U-shaped UHPC beam with other outer U-shaped UHPC beams and / or inner U-shaped UHPC beams to obtain a new assembled double U-shaped UHPC main beam structure;

[0031] (4) assembling the new assembled double U-shaped UHPC main beam structure to the position of the main beam section to be maintained, that is, completing the maintenance of the bridge main beam.

[0032] The assembled double U-shaped UHPC main beam structure in the application is connected through the key tooth type connection structure and the mortise and tenon type connection structure, is easy to disassemble and assemble, when a part of the main beam of a section needs to be maintained, the part can be disassembled and the main beam section can be disassembled, and the part needing maintenance can be replaced, without the need for overall replacement, so that the maintenance and replacement of the main beam are more convenient. The replaced beam body part can be obtained by processing the beam obtained by disassembling other old bridges, or by using a cast-in-place beam body.

[0033] As a general technical concept, the application further provides a bridge main beam recycling method, comprising the following steps:

[0034] (1) cutting the main girder of the bridge to be demolished, and disassembling it into main girder segments; the main girder segments are the above-mentioned assembled double-U UHPC main girder structure;

[0035] (2) the outer U-shaped UHPC beam and the inner U-shaped UHPC beam obtained by disassembling the main girder segments;

[0036] (3) maintaining and detecting the disassembled outer U-shaped UHPC beam and inner U-shaped UHPC beam, and screening out the outer U-shaped UHPC beam and / or inner U-shaped UHPC beam with qualified physical and mechanical indexes for storage;

[0037] (4) recombining the outer U-shaped UHPC beam and / or inner U-shaped UHPC beam with qualified physical and mechanical indexes, or recombining the outer U-shaped UHPC beam and / or inner U-shaped UHPC beam with qualified physical and mechanical indexes with other outer U-shaped UHPC beams and / or inner U-shaped UHPC beams, to obtain a new assembled double-U UHPC main girder structure, and combining the new assembled double-U UHPC main girder structure, i.e. obtaining a new bridge main girder.

[0038] The assembled double-U UHPC main girder structure in the application is connected through a key-tooth type connection structure and a mortise and tenon type connection structure, is easy to disassemble and assemble, when the bridge reaches the service life or the bearing capacity cannot meet the requirements, the main girder can be disassembled and disassembled to obtain an outer U-shaped UHPC beam and an inner U-shaped UHPC beam, the disassembled outer U-shaped UHPC beam and inner U-shaped UHPC beam can be reassembled with other outer U-shaped UHPC beams and inner U-shaped UHPC beams to obtain a new assembled double-U UHPC main girder structure, or directly used as a single-U UHPC beam, which can greatly improve the recycling rate and application scenarios of the main girder.

[0039] The present application is to ensure that the outer U-shaped UHPC beam and the inner U-shaped UHPC beam can work together to ensure normal stress performance and improve the cross-section distortion problem. When two independent beams are connected to work together, constraints need to be provided to prevent the two beams from having a large relative displacement in the transverse and longitudinal directions, which affects the integrity. The present application limits the sliding between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam in the longitudinal direction through the key-tooth type connection structure, and limits the sliding between the outer U-shaped UHPC beam and the inner U-shaped UHPC beam in the longitudinal and transverse directions through the mortise and tenon type connection structure. Moreover, by setting the mortise and tenon type connection structure, the mortise and tenon structure improves the integrity of the two beams in the transverse direction, and the torsional stiffness of the two beams as a whole is also improved, which improves the carrying capacity of the bridge to a certain extent. By setting the key-tooth type connection structure, the misalignment of the two beams in the longitudinal direction is improved, further improving the integrity of the beam and the stress property of the main beam. Overall, the outer U-shaped UHPC beam and the inner U-shaped UHPC beam of the present application can realize the connection integrity of the outer U-shaped UHPC beam and the inner U-shaped UHPC beam through the key-tooth type connection structure and the mortise and tenon type connection structure, and are conducive to improving the mechanical properties of the assembled double U-shaped UHPC main beam structure.

[0040] Compared with the prior art, the present application has the following advantages:

[0041] The assembled double U-shaped UHPC main beam structure of the present application can be applied to various scenes such as pedestrian bridge main beams, and the outer U-shaped UHPC beam and the inner U-shaped UHPC beam can be detachably overlapped and embedded to simply realize the conversion between the main beam structure disassembly and reconstruction, and improve the economic benefit and environmental value of UHPC through recycling. The outer U-shaped UHPC beam and the inner U-shaped UHPC beam can be disassembled and assembled as needed, which can facilitate the regulation of the mechanical properties of the main beam and the regulation of the carrying capacity, and is conducive to solving the problems in the prior art that the application scene of the UHPC main beam obtained by disassembling the old bridge is limited, the recycling performance is not good, and the carrying capacity is difficult to regulate. At the same time, since the outer U-shaped UHPC beam and the inner U-shaped UHPC beam are detachable structures, when a part of the bridge needs to be repaired, the part to be repaired can be disassembled and replaced, without the need for overall replacement, which is convenient for maintenance and replacement, and the maintenance cost is low; when the bridge reaches the service life or the carrying capacity does not meet the requirements, the outer U-shaped UHPC beam and the inner U-shaped UHPC beam can be disassembled and reassembled according to the needs, which is convenient for further recycling. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0043] Figure 1 This is a three-dimensional schematic diagram of the prefabricated double U-shaped UHPC main beam structure in the embodiment.

[0044] Figure 2 for Figure 1 Three-dimensional schematic diagrams of U-shaped UHPC beams from China and abroad.

[0045] Figure 3 for Figure 1 A three-dimensional schematic diagram of the U-shaped UHPC beam in the center.

[0046] Figure 4 for Figure 1 Top view of the dumbbell-shaped double tenon and its embedded beam section.

[0047] Figure 5 for Figure 1 A schematic diagram of the key tooth type connection structure.

[0048] Legend:

[0049] 1. Outer U-shaped UHPC beam; 2. Inner U-shaped UHPC beam; 3. Key-tooth type connection structure; 31. Key-tooth type protrusion; 32. Key-tooth type groove; 4. Mortise and tenon type connection structure; 41. First mortise; 42. Second mortise; 43. Tenon assembly. Detailed Implementation

[0050] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0051] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0052] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0053] Example:

[0054] like Figures 1-3 As shown, the assembled double U-shaped UHPC main beam structure of this embodiment includes an outer U-shaped UHPC beam 1 and an inner U-shaped UHPC beam 2. The inner U-shaped UHPC beam 2 is embedded in the inner cavity of the outer U-shaped UHPC beam 1. A connecting component is provided between the outer U-shaped UHPC beam 1 and the inner U-shaped UHPC beam 2 for detachable and fixed connection.

[0055] Specifically, as shown in Figures 2-4 In this embodiment, the connecting assembly includes a key-tooth type connecting structure 3 arranged between the inner cavity bottom surface of the outer U-shaped UHPC beam 1 and the outer wall bottom surface of the inner U-shaped UHPC beam 2.

[0056] In this embodiment, the key-tooth type connecting structure 3 includes a plurality of key-tooth type protrusions 31 arranged on the inner cavity bottom surface of the outer U-shaped UHPC beam 1 and a plurality of key-tooth type grooves 32 arranged on the outer wall bottom surface of the inner U-shaped UHPC beam 2, and the key-tooth type protrusions 31 and the key-tooth type grooves 32 are matched with each other.

[0057] In this embodiment, the key-tooth type protrusions 31 are arranged on the inner cavity bottom surface of the outer U-shaped UHPC beam 1 in the transverse bridge direction, and the cross section of the key-tooth type protrusions 31 is a trapezoidal shape with a narrow upper part and a wide lower part.

[0058] Specifically, as shown in Figures 2-3 , Figure 5 In this embodiment, the connecting assembly includes a mortise-tenon type connecting structure 4 arranged between the inner side top of the web of the outer U-shaped UHPC beam 1 and the outer side top of the web of the inner U-shaped UHPC beam 2.

[0059] In this embodiment, the mortise-tenon type connecting structure 4 includes a plurality of first mortise slots 41 arranged on the inner side top of the web of the outer U-shaped UHPC beam 1, a plurality of second mortise slots 42 arranged on the outer side top of the web of the inner U-shaped UHPC beam 2, and a plurality of tenon assemblies 43, the first mortise slots 41 and the second mortise slots 42 correspond one by one, and the tenon assembly 43 is a dumbbell-shaped bidirectional tenon with one end detachably clamped in the first mortise slot 41 and the other end detachably clamped in the second mortise slot 42.

[0060] The reconstruction method of the fabricated double U-shaped UHPC girder structure of the present embodiment can include the following steps:

[0061] (1) Cutting the main girder of the bridge to be demolished to deconstruct it into main girder segments; the main girder of the above-mentioned bridge is a single U-shaped UHPC main girder;

[0062] (2) Maintaining and detecting the deconstructed main girder segments, and selecting main girder segments with qualified physical and mechanical indicators for storage;

[0063] (3) Selecting main girder segments of the required size and mechanical indicators according to the design requirements of the main girder of the newly built bridge for standby;

[0064] (4) Processing the main girder segments selected in step (3) to form an outer U-shaped UHPC beam 1 and an inner U-shaped UHPC beam 2 that can be connected by a connecting assembly, and connecting the outer U-shaped UHPC beam 1 and the inner U-shaped UHPC beam 2 by the connecting assembly, thereby obtaining a fabricated double U-shaped UHPC girder structure.

[0065] The bridge girder maintenance method of the embodiment can include the following steps:

[0066] (1) cutting the main girder section of the bridge to be maintained; the main girder section to be maintained is the assembled double-U-shaped UHPC girder structure;

[0067] (2) the outer U-shaped UHPC girder 1 and the inner U-shaped UHPC girder 2 obtained by disassembling the main girder section to be maintained;

[0068] (3) replacing the damaged outer U-shaped UHPC girder 1 and / or inner U-shaped UHPC girder 2 with other outer U-shaped UHPC girders 1 and / or inner U-shaped UHPC girders 2 to obtain a new assembled double-U-shaped UHPC girder structure;

[0069] (4) assembling the new assembled double-U-shaped UHPC girder structure to the position of the main girder section to be maintained, that is, completing the maintenance of the bridge girder.

[0070] The bridge girder recycling method of the embodiment can include the following steps:

[0071] (1) cutting the main girder of the bridge to be demolished into main girder sections, and disassembling the main girder sections into the assembled double-U-shaped UHPC girder structure;

[0072] (2) the outer U-shaped UHPC girder 1 and the inner U-shaped UHPC girder 2 obtained by disassembling the main girder section;

[0073] (3) maintaining and detecting the outer U-shaped UHPC girders 1 and the inner U-shaped UHPC girders 2 obtained by disassembling, and screening out the outer U-shaped UHPC girders 1 and / or inner U-shaped UHPC girders 2 with qualified physical and mechanical indexes for storage;

[0074] (4) recombining the outer U-shaped UHPC girders 1 and / or inner U-shaped UHPC girders 2 with qualified physical and mechanical indexes, or recombining the outer U-shaped UHPC girders 1 and / or inner U-shaped UHPC girders 2 with qualified physical and mechanical indexes with other outer U-shaped UHPC girders 1 and / or inner U-shaped UHPC girders 2 to obtain a new assembled double-U-shaped UHPC girder structure, and combining the new assembled double-U-shaped UHPC girder structure to obtain a new bridge girder.

[0075] The assembled double-U-shaped UHPC girder structure of the embodiment can be obtained by disassembling, processing and assembling the main girder of an old bridge with a single-U-shaped UHPC girder. Of course, it can also be obtained by casting in whole or in part according to the demand of mechanical properties. The bridge with the assembled double-U-shaped UHPC girder structure of the embodiment is convenient to maintain and replace, and the disassembly and reconstruction construction is also convenient, which is conducive to improving the recycling of the main girder.

Claims

1. A fabricated double U-shaped UHPC girder structure, characterized in that, The application relates to a double-U-shaped UHPC beam structure, which comprises an outer U-shaped UHPC beam (1) and an inner U-shaped UHPC beam (2) embedded in the inner cavity of the outer U-shaped UHPC beam (1), and a connecting assembly is arranged between the outer U-shaped UHPC beam (1) and the inner U-shaped UHPC beam (2) for detachable fixed connection of the outer U-shaped UHPC beam (1) and the inner U-shaped UHPC beam (2). The connecting assembly comprises a key-tooth type connecting structure (3) arranged between the inner cavity bottom surface of the outer U-shaped UHPC beam (1) and the outer wall bottom surface of the inner U-shaped UHPC beam (2). The key-tooth type connecting structure (3) comprises a plurality of key-tooth type protrusions (31) arranged on the inner cavity bottom surface of the outer U-shaped UHPC beam (1) and a plurality of key-tooth type grooves (32) arranged on the outer wall bottom surface of the inner U-shaped UHPC beam (2), and the key-tooth type protrusions (31) and the key-tooth type grooves (32) are matched with each other. The connecting assembly comprises a mortise-tenon type connecting structure (4) arranged between the inner side top of the web of the outer U-shaped UHPC beam (1) and the outer side top of the web of the inner U-shaped UHPC beam (2). The mortise-tenon type connecting structure (4) comprises a plurality of first mortise grooves (41) arranged on the inner side top of the web of the outer U-shaped UHPC beam (1), a plurality of second mortise grooves (42) arranged on the outer side top of the web of the inner U-shaped UHPC beam (2) and a plurality of tenon head assemblies (43), the first mortise grooves (41) and the second mortise grooves (42) are one-to-one corresponding, and the tenon head assembly (43) is a dumbbell type bidirectional tenon head which is detachably arranged in the first mortise groove (41) at one end and is detachably arranged in the second mortise groove (42) at the other end.

2. The prefabricated double-U UHPC girder structure according to claim 1, characterized in that, The key-tooth type protrusions (31) are arranged on the inner cavity bottom surface of the outer U-shaped UHPC beam (1) in the transverse bridge direction, and the cross section of the key-tooth type protrusions (31) is a trapezoid with a narrow upper part and a wide lower part.

3. A retrofit method of the fabricated double-U UHPC girder structure of claim 1 or 2, characterized in that, The application further discloses a reconstruction method of the double-U-shaped UHPC beam structure. (1) The main beam of the bridge to be removed is cut to be decomposed into main beam segments; the main beam of the bridge is a single U-shaped UHPC main beam; (2) The main beam segments obtained by decomposition are maintained and detected, and the main beam segments with qualified physical and mechanical indexes are selected and stored for standby use; (3) The main beam segments with the required size and mechanical indexes are selected according to the design requirements of the main beam of the newly-built bridge for standby use; (4) The main beam segments selected in the step (3) are processed to form the outer U-shaped UHPC beam (1) and the inner U-shaped UHPC beam (2) which can be connected through the connecting assembly, and the outer U-shaped UHPC beam (1) and the inner U-shaped UHPC beam (2) are connected through the connecting assembly, so that the assembled double-U-shaped UHPC main beam structure is obtained.

4. A method of repairing a bridge girder, characterized by, The application further discloses a reconstruction method of the double-U-shaped UHPC beam structure. (1) The main beam segment of the bridge to be repaired is cut; the main beam segment to be repaired is the assembled double-U-shaped UHPC main beam structure in the application or the assembled double-U-shaped UHPC main beam structure obtained by the reconstruction method in the application; (2) The outer U-shaped UHPC beam (1) and the inner U-shaped UHPC beam (2) obtained by decomposing the main beam segment to be repaired; (3) replacing the damaged outer U-shaped UHPC beam (1) and / or inner U-shaped UHPC beam (2) with other outer U-shaped UHPC beams (1) and / or inner U-shaped UHPC beams (2) to obtain a new prefabricated double U-shaped UHPC girder structure; (4) assembling the new prefabricated double U-shaped UHPC girder structure to the position of the above-mentioned main girder segment to be repaired, that is, completing the repair of the bridge girder.

5. A method of recycling a bridge girder, characterized by, The method comprises the following steps: (1) cutting the main girder of the bridge to be demolished and deconstructing it into main girder segments; the main girder segments are the prefabricated double U-shaped UHPC girder structure of claim 1 or 2 or the prefabricated double U-shaped UHPC girder structure obtained by the reconstruction method of claim 3; (2) deconstructing the main girder segments to obtain outer U-shaped UHPC beams (1) and inner U-shaped UHPC beams (2); (3) maintaining and detecting the deconstructed outer U-shaped UHPC beams (1) and inner U-shaped UHPC beams (2), and selecting outer U-shaped UHPC beams (1) and / or inner U-shaped UHPC beams (2) with qualified physical and mechanical indexes for storage; (4) recombining the outer U-shaped UHPC beams (1) and / or inner U-shaped UHPC beams (2) with qualified physical and mechanical indexes, or recombining the outer U-shaped UHPC beams (1) and / or inner U-shaped UHPC beams (2) with qualified physical and mechanical indexes with other outer U-shaped UHPC beams (1) and / or inner U-shaped UHPC beams (2) to obtain a new prefabricated double U-shaped UHPC girder structure, and assembling the new prefabricated double U-shaped UHPC girder structure to obtain a new bridge girder.

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