Method, equipment, medium and device for obtaining mechanical properties of bonded surface of simply supported box girder

Abstract

The present invention relates to the field of bridge construction technology, and in particular to a method, equipment, medium and device for obtaining the stress performance of the bonding surface of a simply supported box girder. The present invention proposes a method for obtaining the stress performance of the bonding surface of a simply supported box girder, which performs load simulation in a first constitutive model of a concrete beam segment to obtain the first constitutive performance of the concrete beam segment; then, according to preset data, a model of a structural adhesive bonding segment is constructed at the end of the first constitutive model to obtain a second constitutive model; next, load simulation is performed in the second constitutive model to obtain the second constitutive performance of the structural adhesive bonding segment; finally, the second constitutive performance is analyzed to obtain the stress performance of the corresponding bonding surface, so that the present invention can obtain the stress performance of the bonding surface of a simply supported box girder during specific implementation, thereby solving the defect in related technologies that the stress performance of the bonding surface cannot be accurately obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and in particular to a method, equipment, medium and device for obtaining the mechanical properties of the bonding surface of a simply supported box girder. Background Art

[0002] In recent years, with the rapid development of my country's economy, people's demand for travel has gradually increased, and investment in the construction of high-speed railways, highways, and urban rail transit has continued to increase. New bridges are becoming increasingly diverse. Research on segmental prefabrication and assembly construction technology began early abroad, and in China, research on segmental prefabrication and assembly box girder construction technology began in the 1960s and began to be applied in engineering practice. Segmental assembled box girders are connected by adhesive joints. To improve the durability and shear resistance of the joints, shear keys are installed on the top plate, web, and bottom plate of the joint surface. The adhesive performance of the joint and the stress conditions of the adhesive joint surface determine the quality of the project.

[0003] Bridge construction plays an increasingly important role in railway engineering. Bridge construction must not only consider basic practical needs but also functionality and aesthetics, placing higher demands on bridge design and construction. The main difference between segmental prefabricated bridges and traditional cast-in-place concrete bridges lies in the joints between the segments. The longitudinal steel bars of these bridges are disconnected at these joints, creating weak points in the entire structure. Conventional technologies have been unable to accurately measure the mechanical properties of the bonded surfaces. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method, equipment, medium and device for obtaining the stress performance of the bonding surface of a simply supported box girder, aiming to solve the technical problem in related technologies that the stress performance of the bonding surface cannot be accurately obtained.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for obtaining the mechanical properties of the bonded surface of a simply supported box girder, wherein the simply supported box girder is made by bonding at least two prefabricated box girder segments, wherein the prefabricated box girder segments include concrete beam segments, and both ends of the concrete beam segments are formed with multiple keyways, wherein the keyways at one end of the concrete beam segment correspond one-to-one with the keyways on the next adjacent concrete beam segment to form a bonding area, and the bonding area can be filled with structural adhesive to form a structural adhesive bonding section.

[0007] The method for obtaining the mechanical properties of the bonded surface of a simply supported box beam comprises the following steps:

[0008] Performing a load simulation within a first constitutive model of the concrete beam segment to obtain a first constitutive property of the concrete beam segment; wherein the first constitutive model includes a stress model and a strain relationship model of the concrete beam segment;

[0009] According to the preset data, a model of the structural adhesive bonding section is constructed at the end of the first constitutive model to obtain a second constitutive model; wherein the second constitutive model includes a stress model and a strain relationship model of the structural adhesive bonding section;

[0010] Performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly segment;

[0011] The second constitutive property is analyzed to obtain the corresponding mechanical properties of the bonding surface.

[0012] Optionally, the concrete beam is made of concrete material;

[0013] Before the step of performing load simulation in the first constitutive model of the concrete beam segment to obtain the first constitutive properties of the concrete beam segment, the method further includes:

[0014] Establishing a three-dimensional model of the concrete beam segment;

[0015] applying a uniaxial compressive load in the three-dimensional model to obtain a uniaxial stress-strain model of the concrete material;

[0016] Modifying the yield criterion of the concrete material according to the uniaxial stress-strain model to obtain a yield function;

[0017] The yield function is implanted into the three-dimensional model to form the first constitutive model.

[0018] Optionally, before the step of implanting the yield function into the three-dimensional model to form the first constitutive model, the method further includes:

[0019] applying a load in the three-dimensional model to cause the concrete material to become a plastic state;

[0020] In the plastic state, a mathematical relationship between the stress increment and the strain increment of the three-dimensional model is established and corresponding flow law parameters are obtained.

[0021] Optionally, the step of implanting the yield function into the three-dimensional model to form the first constitutive model includes:

[0022] The yield function and the flow law parameters are implanted into the three-dimensional model to form the first constitutive model.

[0023] Optionally, the structural adhesive includes epoxy resin structural adhesive;

[0024] Before the step of performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly section, the method includes:

[0025] Applying a tensile load within the first constitutive model and obtaining a first tensile strength of the concrete material;

[0026] The tensile load is applied in the second constitutive model, and the second tensile strength of the epoxy resin structural adhesive is obtained:

[0027] The first tensile strength and the second tensile strength are compared and analyzed to obtain a failure sequence of the concrete material and the epoxy resin structural adhesive.

[0028] Optionally, the step of performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly section includes:

[0029] Applying a tensile load within the first constitutive model and obtaining a first elastic modulus of the concrete material;

[0030] Performing load simulation in the second constitutive model to obtain a second elastic modulus of the structural adhesive bonding section;

[0031] The first elastic modulus and the second elastic modulus are compared and analyzed, and a reduction rate of the structural adhesive is obtained to form a second constitutive property of the structural adhesive bonding segment.

[0032] Optionally, the step of constructing a model of the structural adhesive assembly segment at the end of the first constitutive model according to preset data to obtain a second constitutive model includes:

[0033] According to the preset data, a second model of the structural adhesive bonding section is constructed at the end of the first constitutive model;

[0034] Dividing the second model into units and grids according to the preset data to form a grid model;

[0035] Constraints and preset loads are applied within the grid model to obtain the second constitutive model.

[0036] Based on the same technical concept, in a second aspect, the present invention proposes a device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder. The device comprises: a memory, a processor, and a program for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder stored in the memory.

[0037] The program for obtaining the mechanical properties of the bonding surface of the prefabricated simply supported box girder is executed by the processor to implement the steps of the method for obtaining the mechanical properties of the bonding surface of the simply supported box girder described in the first aspect.

[0038] Based on the same technical concept, in the third aspect, the present invention proposes a storage medium, which is a computer-readable storage medium, and a program for obtaining the stress performance of the bonding surface of a prefabricated simply supported box girder is stored on the computer-readable storage medium. The program for obtaining the stress performance of the bonding surface of a prefabricated simply supported box girder is executed by a processor to implement the steps of the method for obtaining the stress performance of the bonding surface of a simply supported box girder described in the first aspect.

[0039] Based on the same technical concept, in a third aspect, the present invention proposes a device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder, comprising:

[0040] a first constitutive property acquisition module, configured to perform load simulation in a first constitutive model of the concrete beam segment to obtain first constitutive properties of the concrete beam segment;

[0041] A second constitutive model construction module is used to construct a model of the structural adhesive assembly section at the end of the first constitutive model according to preset data to obtain a second constitutive model;

[0042] A second constitutive property acquisition module is used to perform load simulation in the second constitutive model to obtain the second constitutive property of the structural adhesive assembly section; and

[0043] The analysis module is used to analyze the second constitutive property and obtain the corresponding mechanical properties of the bonding surface.

[0044] The above one or more technical solutions provided by the present invention may have the following advantages or at least achieve the following technical effects:

[0045] The present invention proposes a method for obtaining the stress performance of the bonding surface of a simply supported box girder. The method performs load simulation in a first constitutive model of the concrete beam segment to obtain the first constitutive performance of the concrete beam segment; then, based on preset data, a model of the structural adhesive bonding segment is constructed at the end of the first constitutive model to obtain a second constitutive model; next, load simulation is performed in the second constitutive model to obtain the second constitutive performance of the structural adhesive bonding segment; finally, the second constitutive performance is analyzed to obtain the stress performance of the corresponding bonding surface. This allows the present invention to obtain the stress performance of the bonding surface of a simply supported box girder during specific implementation, thereby solving the defect in related technologies that the stress performance of the bonding surface cannot be accurately obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these provided drawings without paying any creative work.

[0047] Figure 1 This is a flow chart of a method for obtaining the mechanical properties of the cemented surface of a simply supported box girder according to an example of the present invention;

[0048] Figure 2 for Figure 1 Flowchart of step S100 in the example;

[0049] Figure 3 for Figure 1 Flowchart of step S200 in the example;

[0050] Figure 4 for Figure 1 Flowchart of step S300 in the example;

[0051] Figure 5 Flowcharts of some specific embodiments of the exemplary methods of the present invention;

[0052] Figure 6 A detailed schematic diagram of an acquisition device according to an example of the present invention;

[0053] Figure 7 This is a schematic diagram of a box girder shear key according to an example of the present invention;

[0054] Figure 8 Schematic diagram of the dt model of the present invention;

[0055] Figure 9 This is a schematic diagram of a DC model according to an example of the present invention;

[0056] FIG10( a ) is a schematic diagram of a beam end model according to an example of the present invention, and FIG10( b ) is a schematic diagram of a mid-span model according to an example of the present invention;

[0057] FIG11( a ) is a schematic diagram of a beam end meshing model according to an example of the present invention, and FIG11( b ) is a schematic diagram of a mid-span meshing model according to an example of the present invention;

[0058] Figure 12 Schematic diagram of the boundary and load model at the support point of the present invention;

[0059] FIG13( a ) is a schematic diagram of the mid-span deformation and stress distribution model of an example of the present invention, and FIG13( b ) is a schematic diagram of the cementation surface deformation and stress distribution model of an example of the present invention;

[0060] Figure 14 Schematic diagram of the stress cross section of the cementing surface according to the present invention;

[0061] FIG15( a ) is a schematic diagram of the stress distribution and deformation model of the support of an example of the present invention; FIG15( b ) is a schematic diagram of the stress distribution and deformation model at the bonding surface of an example of the present invention;

[0062] Figure 16 Schematic diagram of stress cross section at the bonding surface of an example of the present invention;

[0063] Figure 17 This is a schematic diagram of the DAMGET distribution at the cementing surface of the present invention;

[0064] Figure 18 Schematic diagram of DAMGEC distribution at the cementing surface of the present invention;

[0065] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0066] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0067] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0068] In the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "include..." does not exclude the presence of other identical elements in the process, method, article or system comprising the element. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which both A and B are satisfied.

[0069] In the present invention, unless otherwise clearly specified or limited, the terms "connection", "fixed", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection between two elements or the interaction relationship between two elements.

[0070] In the present invention, if there are descriptions involving "first," "second," etc., such descriptions are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly specifying the number of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one of such features.

[0071] In the present invention, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention and have no specific meaning. Therefore, "module", "component" or "unit" can be used interchangeably.

[0072] Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances. Furthermore, the technical solutions of the various embodiments may be combined with each other, but this is based on the ability of those skilled in the art to implement them. If a combination of technical solutions contradicts or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0073] The technical concept of the present invention is further described below in conjunction with some specific embodiments.

[0074] The present invention provides a method, equipment, medium and device for obtaining the mechanical properties of the bonding surface of a simply supported box girder.

[0075] In one embodiment of the present invention, see Figures 1 to 17 The method for obtaining the mechanical properties of the bonded surface of this type of simply supported box girder is that the simply supported box girder is made by bonding at least two prefabricated box girder segments. The prefabricated box girder segments include concrete beam segments. Both ends of the concrete beam segments are formed with multiple keyways. The keyways at one end of the concrete beam segment correspond one-to-one with the keyways on the next adjacent concrete beam segment to form a bonding area. The bonding area can be filled with structural adhesive to form a structural adhesive bonding section.

[0076] The method for obtaining the mechanical properties of the bonded surface of a simply supported box girder includes the following steps:

[0077] S100, performing a load simulation within a first constitutive model of the concrete beam segment to obtain a first constitutive property of the concrete beam segment; wherein the first constitutive model includes a stress model and a strain relationship model of the concrete beam segment;

[0078] S200, constructing a model of the structural adhesive bonding section at the end of the first constitutive model according to preset data to obtain a second constitutive model; wherein the second constitutive model includes a stress model and a strain relationship model of the structural adhesive bonding section;

[0079] S300, performing load simulation in the second constitutive model to obtain the second constitutive performance of the structural adhesive assembly segment;

[0080] S400. Analyze the second constitutive performance and obtain the corresponding mechanical properties of the bonding surface.

[0081] In some embodiments, the concrete beam is made of concrete material;

[0082] Before the step of performing load simulation in the first constitutive model of the concrete beam segment to obtain the first constitutive properties of the concrete beam segment, the following steps are further included:

[0083] A100. Establish a three-dimensional model of the concrete beam segment;

[0084] A200, applying uniaxial compressive loads in the three-dimensional model to obtain the uniaxial stress-strain model of the concrete material;

[0085] A300, Modify the yield criterion of concrete material according to the uniaxial stress-strain model to obtain the yield function;

[0086] A400. The yield function is implanted into the three-dimensional model to form the first constitutive model.

[0087] In some embodiments, before the step of implanting the yield function into the three-dimensional model to form the first constitutive model, the method further includes:

[0088] A400, applying loads in a three-dimensional model to make the concrete material become plastic;

[0089] A500. Under the plastic state, establish the mathematical relationship between the stress increment and strain increment of the three-dimensional model and obtain the corresponding flow law parameters.

[0090] In some embodiments, the step of implanting the yield function into the three-dimensional model to form a first constitutive model includes:

[0091] The yield function and flow law parameters are implanted into the three-dimensional model to form the first constitutive model.

[0092] In some embodiments, the structural adhesive comprises an epoxy structural adhesive;

[0093] Before performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly segment, the following steps are included:

[0094] B100, applying a tensile load in the first constitutive model and obtaining the first tensile strength of the concrete material;

[0095] B200. Apply a tensile load in the second constitutive model and obtain the second tensile strength of the epoxy resin structural adhesive:

[0096] B300. Compare and analyze the first tensile strength and the second tensile strength to obtain the failure order of concrete material and epoxy resin structural adhesive.

[0097] In some embodiments, the step of performing load simulation within the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly segment includes:

[0098] S310, applying a tensile load in the first constitutive model and obtaining a first elastic modulus of the concrete material;

[0099] S320, performing load simulation in the second constitutive model to obtain a second elastic modulus of the structural adhesive bonding segment;

[0100] S330 , comparing and analyzing the first elastic modulus and the second elastic modulus, and obtaining a reduction rate of the structural adhesive to form a second constitutive property of the structural adhesive bonding segment.

[0101] In some embodiments, the step of constructing a model of the structural adhesive assembly segment at the end of the first constitutive model according to preset data to obtain the second constitutive model includes:

[0102] S210, constructing a second model of the structural adhesive bonding section at the end of the first constitutive model according to preset data;

[0103] S220, dividing the second model into units and grids according to preset data to form a grid model;

[0104] S230: Apply constraints and preset loads within the grid model to obtain a second constitutive model.

[0105] Based on the same technical concept, in a second aspect, the present invention proposes a device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder. The device comprises: a memory, a processor, and a program for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder stored in the memory.

[0106] The program for obtaining the mechanical properties of the bonding surface of a prefabricated simply supported box girder is executed by the processor to implement the steps of the method for obtaining the mechanical properties of the bonding surface of a simply supported box girder in the first aspect.

[0107] The device for obtaining the stress performance of the bonded surface of a prefabricated simply supported box girder refers to a terminal device or network device that can achieve network connection. The device for obtaining the stress performance of the bonded surface of a prefabricated simply supported box girder can be a terminal device such as a mobile phone, computer, tablet computer, embedded industrial computer, or a network device such as a server or cloud platform.

[0108] like Figure 6 The following is a schematic diagram of the hardware structure of the device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder. The third topic may include: a processor 1001, such as a CPU (Central Processing Unit), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005.

[0109] Those skilled in the art will understand that Figure 6 The hardware structure shown in the figure does not constitute a limitation on the device for obtaining the mechanical properties of the bonded surface of the prefabricated simply supported box girder of the present invention, and may include more or fewer components than shown in the figure, or a combination of certain components, or a different arrangement of components.

[0110] Specifically, the communication bus 1002 is used to implement connection and communication between these components;

[0111] The user interface 1003 is used to connect to the client and perform data communication with the client. The user interface 1003 may include an output unit, such as a display screen, and an input unit, such as a keyboard;

[0112] The network interface 1004 is used to connect to the backend server and perform data communication with the backend server. The network interface 1004 may include an input / output interface, such as a standard wired interface or a wireless interface, such as a Wi-Fi interface.

[0113] The memory 1005 is used to store various types of data, which may include, for example, instructions for any application or method in the device for obtaining the mechanical properties of the bonded surface of the prefabricated simply supported box girder, as well as data related to the application. The memory 1005 may be a high-speed RAM memory or a stable memory, such as a disk memory. Optionally, the memory 1005 may also be a storage device independent of the processor 1001, as further described in detail in the following text. Figure 2 , the memory 1005 may include an operating system, a network communication module, a user interface module, and a program for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder;

[0114] The processor 1001 is used to call the prefabricated simply supported box girder bond surface stress performance acquisition program stored in the memory 1005 and perform the following operations:

[0115] S100, performing a load simulation within a first constitutive model of the concrete beam segment to obtain a first constitutive property of the concrete beam segment; wherein the first constitutive model includes a stress model and a strain relationship model of the concrete beam segment;

[0116] S200, constructing a model of the structural adhesive bonding section at the end of the first constitutive model according to preset data to obtain a second constitutive model; wherein the second constitutive model includes a stress model and a strain relationship model of the structural adhesive bonding section;

[0117] S300, performing load simulation in the second constitutive model to obtain the second constitutive performance of the structural adhesive assembly segment;

[0118] S400. Analyze the second constitutive performance and obtain the corresponding mechanical properties of the bonding surface.

[0119] It is understood that the device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder may further include a communication bus, a user interface, and a network interface. The communication bus is used to achieve communication between these components; the user interface is used to connect to a client and communicate data with the client, and may include an output unit, such as a display screen, and an input unit, such as a keyboard; the network interface is used to connect to a backend server and communicate data with the backend server, and may include an input / output interface, such as a standard wired interface or a wireless interface.

[0120] The memory is used to store various types of data, which may include, for example, instructions for any application or method in the device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder, as well as data related to the application. The memory may be implemented by any type of volatile or non-volatile storage device, or a combination thereof, such as static random access memory (SRAM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk. Optionally, the memory may also be a storage device independent of the processor.

[0121] The processor is used to call the program for obtaining the stress performance of the bonded surface of the prefabricated simply supported box girder stored in the memory, and execute the method for obtaining the stress performance of the bonded surface of the prefabricated simply supported box girder as mentioned above. The processor can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor or other electronic components, and is used to execute all or part of the steps of each embodiment of the method for obtaining the stress performance of the bonded surface of the prefabricated simply supported box girder as mentioned above.

[0122] Based on the same technical concept, in the third aspect, the present invention proposes a storage medium, which is a computer-readable storage medium. The computer-readable storage medium stores a program for obtaining the stress performance of the bonded surface of a prefabricated simply supported box girder. The program for obtaining the stress performance of the bonded surface of a prefabricated simply supported box girder is executed by a processor to implement the steps of the method for obtaining the stress performance of the bonded surface of a simply supported box girder in the first aspect.

[0123] Such as flash memory, hard disk, multimedia card, card-type memory (for example, SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic memory, disk, optical disk, server, etc., the storage medium stores a computer program, and the computer program can be executed by one or more processors. When the computer program is executed by the processor, it can realize all or part of the steps of each embodiment of the method for obtaining the stress performance of the bonded surface of the prefabricated simply supported box girder of the present invention.

[0124] Based on the same technical concept, in a third aspect, the present invention proposes a device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder, comprising:

[0125] A first constitutive property acquisition module is used to perform load simulation in the first constitutive model of the concrete beam segment to obtain the first constitutive property of the concrete beam segment;

[0126] A second constitutive model construction module is used to construct a model of the structural adhesive assembly section at the end of the first constitutive model according to preset data to obtain the second constitutive model;

[0127] A second constitutive performance acquisition module is used to perform load simulation in the second constitutive model to obtain the second constitutive performance of the structural adhesive assembly segment; and

[0128] The analysis module is used to analyze the second constitutive performance and obtain the corresponding mechanical performance of the bonding surface.

[0129] In an exemplary embodiment, a 64m long beam segment required for the manufacture of a railway bridge is taken as an example: In recent years, with the rapid development of my country's economy, people's demand for travel has gradually increased, and my country's high-speed railway, highway, and urban rail transit construction has also continued to increase investment. There are more and more new bridge types. The research on segmental prefabrication and assembly construction technology started earlier abroad. In the 1960s, China also began to study the construction technology of segmental prefabrication and assembly box beams and began to use it in engineering practice. The segments of the segmented assembled box beams are connected by adhesive joints. In order to improve the durability and shear resistance of the joints, shear keys are arranged on the top plate, web and bottom plate of the joint surface. The adhesive performance at the joints and the stress conditions of the adhesive joints determine the quality of the project. After years of research and practical testing, good results have been achieved.

[0130] Located in a plain area, the project spans a river. The bridge is 2.239 km long and features 771 piles, 50 piers, and 19 spans of 64-meter-long box girders, each span consisting of 15 segments, for a total of 285 segments. The joints between the segments are bonded using a water-soluble, two-component epoxy adhesive. These joints are adhesive-bonded, without conventional steel reinforcement. Temporary tensioning is performed during the assembly process. After the segments are assembled, the steel strands are bundled and tensioned throughout the spans. The box girders are then erected span by span from piers 29 to 48.

[0131] Appearance properties: Splicing glue is in a stress environment for a long time and needs to have good stress resistance, good toughness and elongation, so the colloid should also have good fineness.

[0132] The color of the mixed and cured structural adhesive should closely match the surface color of the segmented concrete to ensure the aesthetics of the joints. The distinct color contrast between colloids A and B makes them easy to mix. A is beige, while B is dark gray, and the resulting mixture of A and B approaches the color of concrete. Both colloids A and B are fine and smooth, without noticeable graininess.

[0133] Time for glue application: The on-site indirect characterization test is carried out by the smearing method. About 200g of mixed glue is placed in a paper cup. The initial temperature is 28℃. After 1 hour, the highest temperature is 45℃. It is found that the glue is initially viscous and cannot be applied further. This is for reference in on-site construction.

[0134] Colloid Application Performance: Epoxy structural adhesives are significantly affected by temperature, due to their viscosity and properties. This can lead to problems such as viscous colloids in low winter temperatures, making removal, stirring, and application difficult. In high summer temperatures, the colloids can become fluid and easily fall off during application. To meet on-site construction requirements, it is necessary to test the basic application performance of structural adhesives, including AB removal, mixing and stirring properties, and colloid application. Excellent application performance not only improves construction reliability but also significantly increases efficiency.

[0135] A and B have suitable viscosities and are both easy to take out. They mix well and require no effort to stir. The evenly mixed AB glue can be easily spread on the concrete base surface. Carbon bridge splicing glue has excellent workability as a whole.

[0136] Anti-sagging property: The splicing glue should have good anti-sagging property when applied on the facade to avoid construction quality problems such as glue flow and dripping on the splicing surface.

[0137] When the outdoor temperature is 28℃, the colloid is applied on the concrete base surface, and has good anti-sagging properties. The coating thickness reaches 13mm, and there is still no sagging after 76 minutes, which fully meets the requirements of engineering design and construction.

[0138] Bonding time: Bonding time (open time) refers to the time from when the adhesive is applied to the bonding surface to when the adhesive layer begins to harden and cannot be used. The two bonding surfaces must be connected and pressurized within this time.

[0139] The on-site temperature was 24°C, and the bonding time of the bridge splicing glue was tested. After 60 minutes and 70 minutes respectively, the glue was completely able to bond and met the national standard requirements. After 110 minutes, the glue was dry to the touch and further bonding was not recommended, which fully met the requirements of engineering design and construction.

[0140] Extrusion: During prefabricated segment splicing, after the structural adhesive is applied, prestressing is performed accordingly. Good extrusion ensures that the adhesive is fully spread across the splicing interface, thereby ensuring bonding reliability and efficient construction. Two tests were conducted on the test pieces, and both tests showed uniform and continuous adhesive extrusion around the test pieces, with the adhesive filling the bonding surface fully and evenly.

[0141] Water resistance: During the construction of prefabricated segment splicing, structural adhesive connects adjacent concrete prefabricated beams and fills the adhesive joints to prevent water leakage in the adhesive joints. Therefore, the joint adhesive needs to have good water resistance.

[0142] The test was carried out according to the test requirements. After 2 hours of water storage on the bonding surface, there was no obvious water leakage at the joints, which fully met the design requirements.

[0143] Cure Speed: The positive tensile bond test can reflect the development of adhesive strength to a certain extent and briefly characterize the cure speed of the adhesive. In precast segment splicing construction, it is necessary to test the cure speed of structural adhesives.

[0144] According to Appendix U of GB 50550-2010 "Code for Acceptance of Construction Quality of Building Structure Reinforcement Engineering", after the specimen is formed, the positive tensile bond test will begin at the specified time, and then measure it every one hour until the concrete cohesion fails. The test process is recorded. This time, the positive tensile bond strength at 6h, 7h, and 8h is tested.

[0145] Workability on wet base surfaces: During bridge assembly construction, due to many uncertain factors, rain, snow and other weather conditions may occur during the construction process, and the concrete base surface will be wet. The higher the humidity, the more difficult it is to apply the splicing glue. In addition, the wet base surface will seriously affect the bonding performance of the structural adhesive to the base surface, which directly affects the coating thickness of the colloid on the base surface. Therefore, in order to ensure efficient and orderly construction, it is necessary to verify the workability of the splicing glue on the wet base surface. The splicing glue was applied on a wet concrete base surface that had been cured in water for 16 hours at an outdoor temperature of 24°C. The colloid had good adhesion and the coating thickness reached 12mm. After 120 minutes, there was still no dripping or falling off, showing good adhesion on the wet surface, which can meet the design and construction requirements.

[0146] Analysis of the stress performance of the bonding surface: Segmental assembled beam bridges usually have shear keys set at the cross-section, which can be used for matching and docking during construction. After the construction is completed, they play the role of transmitting shear and pressure. The key teeth on the beam section can be divided into: top plate, web plate, and bottom plate according to their position.

[0147] (1) The key teeth at the top plate position are equipped with multiple long trapezoidal key blocks. All key blocks are parallel to the top plate. They are mainly used to facilitate positioning when connecting beam blocks during assembly construction. After the bridge is completed, they are used to transfer the shear force generated by the vehicle running load of the beam section.

[0148] (2) The key teeth at the web are usually arranged as multiple closely distributed long trapezoidal key blocks perpendicular to the vertical edge of the web, mainly used to transfer shear and pressure between segments.

[0149] (3) The bottom plate position key teeth are arranged as trapezoidal blocks parallel to the bottom plate edge, which usually play the role of assisting positioning when assembling and docking the segments during the construction phase.

[0150] (4) The key teeth at the joint between the web and the top plate are generally set as long trapezoidal key blocks of larger size. Their main function is to transmit the shear force caused by various reasons such as overload during the operation of the bridge after the joint pressure is relieved.

[0151] ABAQUS simulation software was used to study concrete structures through numerical simulation. Finite element analysis was performed on segmental beams assembled with precast adhesive joints to analyze the mechanical properties of the joints. Its wide range of applications and ease of use allow for the creation of complex models. Multiple solvers can be used to solve different models and analyze complex structural mechanics problems.

[0152] Concrete constitutive properties: The material's constitutive model, also known as the constitutive relation, is a mathematical model that describes the relationship between stress and strain. A reasonable constitutive relation can best reflect the actual stress state of a segmental box girder structure. Concrete's stress-strain relationship is complex, exhibiting numerous properties, including nonlinearity and elastic-plasticity.

[0153] ABAQUS software is quite powerful in simulating concrete materials. The concrete constitutive relationship of glued-jointed simply supported box beams subjected to bending adopts the plastic damage concrete model to simulate the process from bending cracking to failure of glued-jointed beams. It assumes that the main causes of concrete material failure are compression crushing and tensile cracking [4]. Based on plasticity and continuity, the evolution and yielding of the failure surface are reflected by the plastic strain generated by tensile and compressive loads.

[0154] Uniaxial tension and compression: The stress-strain curves of concrete under uniaxial tension and compression are described in the CDP model using damage plasticity. The initial elastic stiffness damage and degradation of concrete can be represented by the damage variables dt and dc, which are functions of plastic strain, field variables, and temperature.

[0155] Assuming that E0 is the initial lossless elastic stiffness of the material, the stress-strain relationship under compression load and uniaxial tension is as follows:

[0156]

[0157] The effective stresses for compression and tension are:

[0158]

[0159] Yield criterion: The necessary conditions that a material must meet when it begins to plastically deform at a certain point under a complex stress state. The yield criterion of a material is as follows:

[0160]

[0161] Where F is the yield function and C is a constant related to the material.

[0162] The yield criterion in the plastic damage model refers to many suggested yield functions and is modified to take into account the different evolution laws of tension and compression. The yield function of effective stress used in the model is as follows:

[0163]

[0164] Flow law: Before a material enters the plastic state, its stress and strain satisfy Hooke's law. The flow law, also known as the incremental theory, establishes the relationship between the incremental stress and incremental strain after the material enters the plastic state. The CDP model uses an independent flow law, and its functional relationship is shown below:

[0165]

[0166] Constitutive Properties of Structural Adhesives: Extensive testing has shown that the bond strength between epoxy structural adhesives and concrete is far greater than the tensile strength of the concrete itself. When adhesively bonded components fail, the concrete often fails before the adhesive layer. The superior material properties of epoxy joint adhesives over concrete have led some to simplify the epoxy structural adhesive layer into a linear elastic material.

[0167] Research has shown that the elastic modulus of epoxy resin structural adhesives is much smaller than that of concrete, at approximately 20% to 10% of concrete's modulus. This significant difference in elastic modulus leads to a reduction in the elastic modulus within a certain range of the adhesive joint. Research and testing have shown that this reduction is approximately 73% of the concrete's modulus within a certain range near the adhesive joint.

[0168] Geometric model: In order to study the mechanical properties of the bonded surface under bending and shear, three-dimensional solid local models of the mid-span segment and the support segment were established respectively.

[0169] Unit and meshing: Based on the order of the node displacement interpolation in ABAQUS, fully integrated linear units can experience shear locking under bending loads. Based on the actual assembly and loading conditions of the test segment box girder, a corresponding finite element numerical model was established. In the finite element simulation of the model glued test beam, C3D8R units were used for the concrete, loading pads, anchor plates, and structural adhesive [5].

[0170] Because the bond at the bonding surface is small, only 15 cm wide, the mesh size should not be larger than 15 cm to accurately calculate the stress distribution on the bond surface. However, a mesh size that is too small will exponentially increase the calculation time, and the required accuracy for concrete stresses far from the bond surface is not high. Therefore, when meshing, the geometric model is divided into multiple regions, and different mesh sizes are used according to their distance from the bond surface.

[0171] Simulation of bonded joints: Experiments and finite element numerical analysis have shown that when the quality of segmental bonding is good, using ties to bind adjacent segments can better simulate actual forces. All studies on bonded joints use ties to simulate the effects of bonded joints. Tie constraints bind two contacting surfaces together, constraining all translational degrees of freedom. The slave surface is constrained to have the same motion as its closest point on the control surface. The principle of the tie constraint is that nodes on the slave surface cannot intrude into the master control surface, but slave surfaces can intrude between nodes. To ensure more reasonable and accurate simulation results, the master-slave relationship of the tie constraint must select appropriate master and slave surfaces. Therefore, concrete materials with relatively low stiffness should be used as slave surfaces, and the meshing should be more refined.

[0172] Boundaries and Loads: Because this is a localized model and the primary focus is on the bending and shear properties of the bonded surfaces, this study simulates the boundary conditions by imposing fixed constraints on one side of the model and applying shear and bending moments on the other side. Furthermore, the deadweight of the concrete must be considered.

[0173] Bending results at mid-span: The figure shows that the plane cross-section assumption is met, with stress distribution at the bonded surface, high stress above and below the cross-section, low stress near the neutral axis, and no localized stress concentration at the joint. This indicates that under load, the structural adhesive can effectively transfer stress, and the weak link in the cross-section is not at the joint.

[0174] Shear results at the support: The stress distribution at the support is shown below. The figure clearly shows a significant stress concentration at the bond surface, primarily at the root of the key. Some areas have even exceeded the ultimate strength, indicating concrete failure.

[0175] DAMAGT and DAMAGETC characterize the degree of concrete damage under tension and compression, respectively. A larger value indicates more severe damage.

[0176] It can be seen from the figure that the damage at the bonding surface is mainly caused by stress, and the overall distribution is above the neutral axis of the cross section.

[0177] From the above analysis, it can be concluded that the bonded surface has good bending performance but poor shear resistance. Shear failure is mainly distributed above the neutral axis of the bonded surface, and the root area of ​​the connecting key is the spalling link of the entire cross section.

[0178] Segmental box girders enable standardized factory production of long-span box girders, making concrete quality control easier. While the substructure is being constructed, the superstructure beam segments can be prefabricated in parallel. Prefabrication in segments is lightweight, compact, and easy to transport. Segmental assembly minimizes the impact on ground traffic and accelerates construction progress, enabling factory-based prefabrication of long-span bridges. Testing of adhesive bonding materials and research on joint surface stresses have broad market prospects for quality control and widespread application of segmental simply supported box girders.

[0179] The present invention proposes a method for obtaining the stress performance of the bonding surface of a simply supported box girder. The method performs load simulation in a first constitutive model of the concrete beam segment to obtain the first constitutive performance of the concrete beam segment; then, based on preset data, a model of the structural adhesive bonding segment is constructed at the end of the first constitutive model to obtain a second constitutive model; next, load simulation is performed in the second constitutive model to obtain the second constitutive performance of the structural adhesive bonding segment; finally, the second constitutive performance is analyzed to obtain the stress performance of the corresponding bonding surface. This allows the present invention to obtain the stress performance of the bonding surface of a simply supported box girder during specific implementation, thereby solving the defect in related technologies that the stress performance of the bonding surface cannot be accurately obtained.

[0180] It should be noted that the serial numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above embodiments are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structures or equivalent process transformations made by utilizing the contents of the present description and drawings under the inventive concept of the present invention, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for obtaining the mechanical properties of the bonded surface of a simply supported box girder, wherein the simply supported box girder is made by bonding at least two prefabricated box girder segments, wherein the prefabricated box girder segments include concrete beam segments, wherein both ends of the concrete beam segments are formed with a plurality of keyways, wherein the keyways at one end of the concrete beam segment correspond one-to-one with the keyways on the next adjacent concrete beam segment to form a bonding area, wherein the bonding area can be filled with structural adhesive to form a structural adhesive bonding section, wherein the method is characterized in that: The method for obtaining the mechanical properties of the bonded surface of a simply supported box beam comprises the following steps: Performing a load simulation within a first constitutive model of the concrete beam segment to obtain a first constitutive property of the concrete beam segment; wherein the first constitutive model includes a stress model and a strain relationship model of the concrete beam segment; According to the preset data, a model of the structural adhesive bonding section is constructed at the end of the first constitutive model to obtain a second constitutive model; wherein the second constitutive model includes a stress model and a strain relationship model of the structural adhesive bonding section; Performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly segment; Analyze the second constitutive property to obtain the corresponding mechanical properties of the bonding surface; The concrete beam is made of concrete material; The structural adhesive includes epoxy resin structural adhesive; Before the step of performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly section, the method includes: Applying a tensile load within the first constitutive model and obtaining a first tensile strength of the concrete material; The tensile load is applied in the second constitutive model, and the second tensile strength of the epoxy resin structural adhesive is obtained: Comparing and analyzing the first tensile strength and the second tensile strength to obtain a failure sequence of the concrete material and the epoxy resin structural adhesive; The step of performing load simulation in the second constitutive model to obtain the second constitutive properties of the structural adhesive assembly section includes: Applying a tensile load within the first constitutive model and obtaining a first elastic modulus of the concrete material; Performing load simulation in the second constitutive model to obtain a second elastic modulus of the structural adhesive bonding section; The first elastic modulus and the second elastic modulus are compared and analyzed, and a reduction rate of the structural adhesive is obtained to form a second constitutive property of the structural adhesive bonding segment.

2. The method for obtaining the mechanical properties of the bonded surface of a simply supported box beam according to claim 1, characterized in that: Before the step of performing load simulation in the first constitutive model of the concrete beam segment to obtain the first constitutive properties of the concrete beam segment, the method further includes: Establishing a three-dimensional model of the concrete beam segment; applying a uniaxial compressive load in the three-dimensional model to obtain a uniaxial stress-strain model of the concrete material; Modifying the yield criterion of the concrete material according to the uniaxial stress-strain model to obtain a yield function; The yield function is implanted into the three-dimensional model to form the first constitutive model.

3. The method for obtaining the mechanical properties of the bonded surface of a simply supported box beam according to claim 2, characterized in that: Before the step of implanting the yield function into the three-dimensional model to form the first constitutive model, the method further includes: applying a load in the three-dimensional model to cause the concrete material to become a plastic state; In the plastic state, a mathematical relationship between the stress increment and the strain increment of the three-dimensional model is established and corresponding flow law parameters are obtained.

4. The method for obtaining the mechanical properties of the bonded surface of a simply supported box beam according to claim 3, characterized in that: The step of implanting the yield function into the three-dimensional model to form the first constitutive model includes: The yield function and the flow law parameters are implanted into the three-dimensional model to form the first constitutive model.

5. The method for obtaining the mechanical properties of the bonded surface of a simply supported box beam according to any one of claims 1 to 4, characterized in that: The step of constructing a model of the structural adhesive assembly section at the end of the first constitutive model according to preset data to obtain a second constitutive model includes: According to the preset data, a second model of the structural adhesive bonding section is constructed at the end of the first constitutive model; Dividing the second model into units and grids according to the preset data to form a grid model; Constraints and preset loads are applied within the grid model to obtain the second constitutive model.

6. A device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder, characterized in that: The device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder comprises: a memory, a processor, and a program for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder stored in the memory. The program for obtaining the mechanical properties of the bonding surface of a prefabricated simply supported box girder is executed by the processor to implement the steps of the method for obtaining the mechanical properties of the bonding surface of a simply supported box girder as described in any one of claims 1 to 5.

7. A storage medium, wherein the storage medium is a computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program for obtaining the stress performance of the bonded surface of a prefabricated simply supported box girder. The program for obtaining the stress performance of the bonded surface of a prefabricated simply supported box girder is executed by a processor to implement the steps of the method for obtaining the stress performance of the bonded surface of a simply supported box girder as described in any one of claims 1 to 5.

8. A device for obtaining the mechanical properties of the bonding surface of a prefabricated simply supported box girder, characterized in that: For executing the method for obtaining the mechanical properties of the bonded surface of a simply supported box girder according to claim 1, the device for obtaining the mechanical properties of the bonded surface of a prefabricated simply supported box girder comprises: a first constitutive property acquisition module, configured to perform load simulation in a first constitutive model of the concrete beam segment to obtain first constitutive properties of the concrete beam segment; A second constitutive model construction module is used to construct a model of the structural adhesive assembly section at the end of the first constitutive model according to preset data to obtain a second constitutive model; A second constitutive property acquisition module is used to perform load simulation in the second constitutive model to obtain the second constitutive property of the structural adhesive assembly section; and The analysis module is used to analyze the second constitutive property and obtain the corresponding mechanical properties of the bonding surface.

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