Hybrid girder bridge design method and hybrid girder bridge

Abstract

The invention relates to a hybrid girder bridge design method and a hybrid girder bridge, and relates to the technical field of complex line bridge design, and the method comprises the following steps: obtaining initial structure parameters of a hybrid girder and a concrete girder under the same condition based on related design specifications of a steel-concrete composite bridge and a prestressed concrete girder; the mid-span span of the concrete beam is adjusted, so that the maximum bending moments of the middle pier tops in the structural parameters of the concrete beam and the hybrid beam are equal; adjusting the mid-span correlation structure parameters of the hybrid beam to be consistent with the concrete beam, and obtaining the maximum bending moment of the middle pier top after the parameters of the hybrid beam are adjusted; if the variable quantity of the maximum bending moment of the middle pier top after the parameters of the hybrid beam are adjusted is larger than or equal to a set threshold value, the structural parameters of the concrete beam are adjusted, and the maximum bending moment of the middle pier top of the concrete beam is made to be equal to the maximum bending moment of the middle pier top after the parameters of the hybrid beam are adjusted; and adjusting the mid-span correlation structure parameters of the hybrid beam to be consistent with the parameter-updated concrete beam until the maximum bending moment variation of the middle pier top after the parameter adjustment of the hybrid beam is less than a set threshold value.

Description

Technical Field

[0001] This invention relates to the field of double-track bridge design technology, specifically to a hybrid beam bridge design method and a hybrid beam bridge. Background Technology

[0002] With the continuous growth in traffic demand, many highways have launched double-span projects. To meet navigation requirements and reduce bridge water resistance, newly built double-span bridges generally adopt the design of combining multiple spans of the old bridge into a single large span. However, some double-span bridges have very small clearances from the old bridges. If cable-stayed bridges or arch bridges with superstructures are used, the construction process could pose safety risks to the normal operation of the old bridge. When the existing bridge is a beam bridge, using a beam bridge for the new bridge can not only avoid these risks but also maintain consistency with the original bridge type and ensure landscape harmony. However, conventional concrete beam bridges, in large-span design scenarios, suffer from problems such as uncontrollable shrinkage and creep deformation of the main beam, and are prone to deflection and cracking. Against this backdrop, the application of hybrid continuous beams is becoming increasingly widespread. Their core advantage lies in effectively reducing the weight of the mid-span, avoiding some of the problems of large-span concrete beam bridges, while simultaneously increasing the main span and reducing structural weight, precisely meeting the core needs of span increase and load optimization in the renovation of old bridges and the construction of double-span bridges.

[0003] In existing technologies, the design of hybrid beam bridges mainly relies on finite element numerical analysis and analog design methods. This involves establishing a refined three-dimensional finite element model for structural analysis or directly referencing the design parameters and construction measures of existing bridges.

[0004] However, the results of finite element analysis are highly dependent on model assumptions and boundary conditions. For designers who lack engineering experience, it is difficult to accurately grasp the key parameters. On the other hand, the analogy design method lacks enough successful cases for reference, and it is difficult to coordinate the reasonable location of the steel-concrete composite section with the side span and the main beam height to complete the multi-parameter coupled optimization. Summary of the Invention

[0005] This application provides a design method and a hybrid beam bridge, which can solve the problem that the finite element analysis results in the prior art are highly dependent on model assumptions and boundary conditions, making it difficult for designers lacking engineering experience to accurately grasp key parameters. The analog design method, due to the lack of sufficient successful cases for reference, has the problem of difficulty in coordinating the reasonable location of the steel-concrete composite section with the side span and the main beam height to complete multi-parameter coupled optimization.

[0006] In a first aspect, embodiments of this application provide a design method for a hybrid beam bridge, comprising: Based on the relevant design specifications for steel-concrete composite bridges and prestressed concrete beams, the initial structural parameters of the composite beams and concrete beams under the same conditions were obtained. Adjust the mid-span of the concrete beam to make the maximum bending moment at the top of the pier equal in the structural parameters of the concrete beam and the hybrid beam. Adjust the mid-span related structural parameters of the hybrid beam to be consistent with those of the concrete beam, and obtain the maximum bending moment at the top of the mid-pier after the parameters of the hybrid beam are adjusted; If the change in the maximum bending moment at the top of the pier after the adjustment of the hybrid beam parameters is greater than or equal to a set threshold, the structural parameters of the concrete beam are adjusted so that the maximum bending moment at the top of the pier of the concrete beam is equal to the maximum bending moment at the top of the pier after the adjustment of the hybrid beam parameters. The mid-span related structural parameters of the hybrid beam are then adjusted to be consistent with those of the concrete beam after the parameter update, until the change in the maximum bending moment at the top of the pier after the adjustment of the hybrid beam parameters is less than the set threshold.

[0007] In one embodiment, adjusting the structural parameters of the concrete beam to make the maximum bending moment at the top of the pier of the concrete beam equal to the maximum bending moment at the top of the pier of the hybrid beam after parameter adjustment includes: Based on the adjusted mid-span of the concrete beam, adjust the structural parameters associated with the mid-span of the concrete beam. The mid-span of the concrete beam is adjusted again so that the maximum bending moment at the top of the middle pier of the concrete beam is equal to the maximum bending moment at the top of the middle pier of the hybrid beam after parameter adjustment.

[0008] In one embodiment, after adjusting the mid-span of the concrete beam, the method further includes: Determine whether the mid-span of the adjusted concrete beam is greater than the set span of the concrete beam; If not, proceed to the next step; If so, adjust the mid-span of the concrete beam to the set span of the concrete beam, obtain the maximum bending moment at the top of the middle pier in the structural parameters of the concrete beam, adjust the mid-span associated structural parameters of the hybrid beam to be consistent with those of the concrete beam, and increase the length of the mid-span steel beam in the structural parameters of the hybrid beam until the difference between the maximum bending moment at the top of the middle pier in the structural parameters of the hybrid beam and the maximum bending moment at the top of the middle pier in the structural parameters of the concrete beam is less than a set threshold.

[0009] In one implementation, after the hybrid beam parameters are adjusted, the following steps are also included: A set prestress is applied to the adjusted concrete beam to make the concrete beam bear force in accordance with the specification requirements, and the maximum principal tensile stress of the concrete beam and the vertical deflection at the steel-concrete interface caused by shrinkage and creep are obtained. Adjust the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam, and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep, are both less than the preset values.

[0010] In one embodiment, if the condition is not met after adjusting the prestress applied to the hybrid beam: Adjust the height of the top beam of the middle pier of the hybrid beam, and readjust the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep are both less than the preset values.

[0011] In one embodiment, adjusting the height of the top beam of the middle pier of the hybrid beam includes: The height of the top beam of the middle pier of the hybrid beam is increased in increments of 0.1m.

[0012] In one embodiment, when obtaining the maximum bending moment at the top of the pier in the hybrid beam structure parameters: Based on the bending moment envelope diagram of the hybrid beam, the point of zero maximum bending moment is obtained; Adjust the steel-concrete interface to the zero point of maximum bending moment to obtain the maximum bending moment at the top of the middle pier.

[0013] In one embodiment, when obtaining the initial structural parameters of the hybrid beam: Based on navigation and flood control design requirements, the main span is obtained; Based on the main span, the structural parameters associated with the mid-span of the hybrid beam are obtained.

[0014] In one embodiment, adjusting the mid-span related structural parameters of the hybrid beam to be consistent with those of the concrete beam includes: Adjust the side span, top beam height of the middle pier, web thickness, and top and bottom plate thickness of the hybrid beam to be consistent with those of the concrete beam.

[0015] Secondly, this application also provides a hybrid beam bridge, which is constructed using the above-described hybrid beam bridge design method.

[0016] The beneficial effects of the technical solutions provided in this application include: When using this hybrid beam bridge design method, the initial structural parameters of the hybrid beam and concrete beam under the same conditions are first obtained based on the relevant design specifications for steel-concrete composite bridges and prestressed concrete beams. Then, the mid-span of the concrete beam is adjusted to make the maximum bending moment at the top of the pier equal in the structural parameters of the concrete beam and the hybrid beam. The mid-span-related structural parameters of the hybrid beam are adjusted to be consistent with those of the concrete beam, and the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is obtained. If the change in the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is greater than or equal to a set threshold, the structural parameters of the concrete beam are adjusted to make the maximum bending moment at the top of the pier equal to that after the hybrid beam parameters are adjusted. The mid-span-related structural parameters of the hybrid beam are then adjusted to be consistent with those of the concrete beam after the parameter update, until the change in the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is less than the set threshold. By linking the design of hybrid beam bridges with that of concrete beam bridges, and through iterative adjustments to make the hybrid beams and concrete beams approach each other in key parameters such as the maximum bending moment at the top of the pier, the safety reserve of the hybrid beam structure is ensured to be comparable to that of a mature concrete beam bridge. This facilitates rapid design of hybrid beam bridges and solves the problem that in existing technologies, finite element analysis results are highly dependent on model assumptions and boundary conditions, making it difficult for designers lacking engineering experience to accurately grasp key parameters. Furthermore, analogical design methods, due to a lack of sufficient successful cases for reference, struggle to coordinate the reasonable location of the steel-concrete composite section with the span of the side spans and the height of the main beams to complete multi-parameter coupled optimization. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural schematic diagram of an embodiment of a hybrid beam bridge design method according to the present invention.

[0019] Figure 2 This is a schematic diagram of the bending moment envelope of an embodiment of a hybrid beam bridge design method of the present invention.

[0020] Figure 3 This is a schematic diagram of a concrete beam bridge in an embodiment of a hybrid beam bridge design method of the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0022] This application provides a hybrid beam bridge design method and a hybrid beam bridge, which can solve the problem that the finite element analysis results in the prior art are highly dependent on model assumptions and boundary conditions. For designers who lack engineering experience, it is difficult to accurately grasp the key parameters. The analog design method, due to the lack of sufficient successful cases for reference, has the problem of difficulty in coordinating the reasonable location of the steel-concrete composite section with the side span and the main beam height to complete multi-parameter coupling optimization.

[0023] like Figure 1 , Figure 2 and Figure 3 As shown, in this scheme, Lb is the side span of the hybrid beam, Lz is the middle span of the hybrid beam, Hh is the beam height at the top of the pier in the hybrid beam, Lc is the length of the concrete beams on both sides of the middle span of the steel beam in the middle span of the hybrid beam, Ls is the length of the steel beam in the middle span of the hybrid beam, Mt is the maximum bending moment at the top of the pier in the hybrid beam, P2 is the zero point of the maximum bending moment, Lb1 is the side span of the concrete beam, Lz1 is the middle span of the concrete beam, and Hh1 is the beam height at the top of the pier in the concrete beam.

[0024] On the one hand, this application provides a design method for hybrid beam bridges, which includes: Based on the relevant design specifications for steel-concrete composite bridges and prestressed concrete beams, the initial structural parameters of the composite beams and concrete beams under the same conditions were obtained. Adjust the mid-span of the concrete beam to make the maximum bending moment at the top of the pier equal in the structural parameters of the concrete beam and the hybrid beam. Adjust the mid-span related structural parameters of the hybrid beam to be consistent with those of the concrete beam, and obtain the maximum bending moment at the top of the mid-pier after the hybrid beam parameters are adjusted; If the change in the maximum bending moment at the top of the pier after adjusting the parameters of the hybrid beam is greater than or equal to the set threshold, adjust the structural parameters of the concrete beam to make the maximum bending moment at the top of the pier of the concrete beam equal to the maximum bending moment at the top of the pier after adjusting the parameters of the hybrid beam. Adjust the mid-span related structural parameters of the hybrid beam to be consistent with the parameters of the updated concrete beam until the change in the maximum bending moment at the top of the pier after adjusting the parameters of the hybrid beam is less than the set threshold.

[0025] When using this hybrid beam bridge design method, the initial structural parameters of the hybrid beam and concrete beam under the same conditions are first obtained based on the relevant design specifications for steel-concrete composite bridges and prestressed concrete beams. Then, the mid-span of the concrete beam is adjusted to make the maximum bending moment at the top of the pier equal in the structural parameters of the concrete beam and the hybrid beam. The mid-span-related structural parameters of the hybrid beam are adjusted to be consistent with those of the concrete beam, and the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is obtained. If the change in the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is greater than or equal to a set threshold, the structural parameters of the concrete beam are adjusted to make the maximum bending moment at the top of the pier equal to that after the hybrid beam parameters are adjusted. The mid-span-related structural parameters of the hybrid beam are then adjusted to be consistent with those of the concrete beam after the parameter update, until the change in the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is less than the set threshold. By linking the design of hybrid beam bridges with that of concrete beam bridges, and through iterative adjustments to make the hybrid beams and concrete beams approach each other in key parameters such as the maximum bending moment at the top of the pier, the safety reserve of the hybrid beam structure is ensured to be comparable to that of a mature concrete beam bridge. This facilitates rapid design of hybrid beam bridges and solves the problem that in existing technologies, finite element analysis results are highly dependent on model assumptions and boundary conditions, making it difficult for designers lacking engineering experience to accurately grasp key parameters. Furthermore, analogical design methods, due to a lack of sufficient successful cases for reference, struggle to coordinate the reasonable location of the steel-concrete composite section with the span of the side spans and the height of the main beams to complete multi-parameter coupled optimization.

[0026] In some optional embodiments, adjusting the structural parameters of the concrete beam to make the maximum bending moment at the top of the pier equal to the maximum bending moment at the top of the pier after parameter adjustment of the hybrid beam includes: Based on the adjusted mid-span of the concrete beam, adjust the structural parameters associated with the mid-span of the concrete beam. The mid-span of the concrete beam was adjusted again to make the maximum bending moment at the top of the middle pier of the concrete beam equal to the maximum bending moment at the top of the middle pier of the hybrid beam after parameter adjustment.

[0027] In this embodiment, the structural parameters of the concrete beam are adjusted to make the maximum bending moment at the pier top of the concrete beam equal to the maximum bending moment at the pier top of the hybrid beam after parameter adjustment. Specifically, this includes: adjusting the structural parameters associated with the mid-span of the concrete beam based on the adjusted mid-span; and then adjusting the mid-span again to make the maximum bending moment at the pier top of the concrete beam equal to the maximum bending moment at the pier top of the hybrid beam after parameter adjustment. This step-by-step adjustment method is more scientific and reasonable than adjusting all parameters at once. It ensures the rationality of the structural parameters first, and then accurately matches key stress indicators, significantly improving the matching accuracy of the bending moment parameters at the pier top between the concrete beam and the hybrid beam, laying a reliable foundation for subsequent design iterations. Furthermore, by establishing a reasonable parameter adjustment logic chain, design oscillations caused by blind adjustments are avoided, making the iteration process more stable and convergent, effectively reducing the number of iterations required to achieve the design goal, and improving design efficiency.

[0028] In some optional embodiments, after adjusting the mid-span of the concrete beam, the method further includes: Determine whether the mid-span of the adjusted concrete beam is greater than the set span of the concrete beam; If not, proceed to the next step; If so, adjust the mid-span of the concrete beam to the set span of the concrete beam, obtain the maximum bending moment at the top of the middle pier in the structural parameters of the concrete beam, adjust the mid-span related structural parameters of the hybrid beam to be consistent with those of the concrete beam, and increase the length of the mid-span steel beam in the structural parameters of the hybrid beam until the difference between the maximum bending moment at the top of the middle pier in the structural parameters of the hybrid beam and the maximum bending moment at the top of the middle pier in the structural parameters of the concrete beam is less than the set threshold.

[0029] In this embodiment, after adjusting the mid-span of the concrete beam, the process further includes: determining whether the adjusted mid-span of the concrete beam is greater than the set span of the concrete beam; if not, proceeding to the next step; if so, adjusting the mid-span of the concrete beam to the set span, obtaining the maximum bending moment at the top of the middle pier in the concrete beam structural parameters, adjusting the mid-span-related structural parameters of the hybrid beam to be consistent with those of the concrete beam, and increasing the length of the mid-span steel beam in the hybrid beam structural parameters until the difference between the maximum bending moment at the top of the middle pier in the hybrid beam structural parameters and the maximum bending moment at the top of the middle pier in the concrete beam structural parameters is less than a set threshold. By setting a set span threshold for the concrete beam, when the calculated span of the concrete beam exceeds a reasonable range, the design strategy is adjusted in a timely manner, utilizing the steel beam to partially share the load, allowing the steel to bear more tensile stress and the concrete to bear more compressive stress, fully leveraging the advantages of both materials. Furthermore, determining the reasonableness of the concrete beam span early in the design process avoids subsequent invalid parameter adjustments and iterative calculations based on unreasonable concrete beam spans, significantly improving design efficiency and reducing computational resource waste.

[0030] In some optional embodiments, after the hybrid beam parameters are adjusted, the following steps are also included: Prestress was applied to the adjusted concrete beam to ensure that the concrete beam was subjected to stress in accordance with the specifications, and the maximum principal tensile stress of the concrete beam and the vertical deflection at the steel-concrete interface caused by shrinkage and creep were obtained. Adjust the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam, and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep, are both less than the preset values.

[0031] In this embodiment, after the hybrid beam parameters are adjusted, the process further includes: applying a prestress to the adjusted concrete beam to ensure that the concrete beam's stress meets the specifications, and obtaining the maximum principal tensile stress of the concrete beam and the vertical deflection at the steel-concrete interface caused by shrinkage and creep; adjusting the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete beam and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep are both less than preset values. By controlling the difference between the maximum principal tensile stress of the hybrid beam and the concrete beam within a preset range, the stress state of the concrete portion in the hybrid beam is ensured to be comparable to that of concrete beam bridges that have undergone long-term engineering verification, effectively controlling the risk of concrete cracking and significantly improving the structural safety of the hybrid beam bridge. Furthermore, through fine adjustment of the prestress, the long-term deformation index of vertical deflection at the steel-concrete interface caused by shrinkage and creep is effectively controlled, avoiding the common deflection problem in hybrid beam bridges and ensuring the bridge's linear stability and driving comfort.

[0032] In some alternative embodiments, if the condition is not met after adjusting the prestress applied to the hybrid beam: Adjust the height of the top beam of the middle pier of the hybrid beam and readjust the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep are both less than the preset values.

[0033] In this embodiment, if the condition is not met after adjusting the prestress applied to the hybrid beam: The height of the top beam of the middle pier of the hybrid beam is adjusted, and the prestress applied to the hybrid beam is readjusted until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam, and the difference in vertical deflection at the steel-concrete interface caused by shrinkage and creep, are both less than the preset values. When prestress adjustment alone cannot meet the design requirements, this step provides a clear remedial path, avoids design dead ends, ensures the continuity and feasibility of the design process, effectively solves the prestress adjustment limit problem in hybrid beam design, and achieves synergistic optimization of structural geometric and mechanical parameters by combining beam height adjustment with prestress adjustment. This overcomes the limitations of single parameter adjustment and allows the stress state of the hybrid beam to more accurately match the mature design experience of concrete beam bridges.

[0034] In some optional embodiments, adjusting the height of the top beam of the pier of the hybrid beam includes: The height of the top beam of the middle pier of the hybrid beam is increased in increments of 0.1m.

[0035] In this embodiment, adjusting the height of the top beam at the middle pier of the hybrid beam specifically includes increasing the height of the top beam at the middle pier in increments of 0.1m. Using a fixed gradient to adjust the beam height ensures the precision of the design adjustment while avoiding a sharp increase in computational load due to excessively small gradients, and preventing oscillations in design parameters due to excessively large adjustment ranges. This makes the design process more stable and convergent, achieving the best balance between design accuracy and computational efficiency, and significantly improving the overall efficiency of hybrid beam bridge design.

[0036] In some optional embodiments, when obtaining the maximum bending moment at the top of the pier for the hybrid beam structure parameters: Based on the bending moment envelope diagram of the hybrid beam, the point of zero maximum bending moment is obtained; Adjust the steel-concrete interface to the zero point of maximum bending moment to obtain the maximum bending moment at the top of the middle pier.

[0037] In this embodiment, when obtaining the maximum bending moment at the top of the middle pier of the hybrid beam structure: based on the bending moment envelope diagram of the hybrid beam, the zero point of the maximum bending moment is obtained; the steel-concrete interface is adjusted to the zero point of the maximum bending moment to obtain the maximum bending moment at the top of the middle pier. The steel-concrete interface is a weak link in the hybrid beam bridge, with severe stress concentration. By setting the steel-concrete interface at the zero-moment position, the bending moment and shear force at this position are significantly reduced, effectively reducing interface stress concentration and greatly improving the overall durability and service life of the hybrid beam bridge.

[0038] In some optional embodiments, when obtaining the initial structural parameters of the hybrid beam: Based on navigation and flood control design requirements, the main span is obtained; Based on the main span, obtain the structural parameters associated with the mid-span of the hybrid beam.

[0039] In this embodiment, when obtaining the initial structural parameters of the hybrid beam: the main span is obtained based on navigation and flood control design requirements; and the mid-span related structural parameters of the hybrid beam are obtained based on the main span. Firstly, the main span is determined based on actual engineering requirements such as navigation and flood control, ensuring that the bridge design is fundamentally based on meeting functional needs. This avoids the design pitfall of sacrificing engineering practicality for structural form, enabling the bridge to truly serve its intended function. By using the main span as the benchmark for determining initial parameters, it conforms to the basic design principle that the span of a bridge structure determines its dimensions, providing a scientific and reasonable starting point for subsequent hybrid beam design. This avoids the arbitrariness and blindness in parameter determination in traditional design, facilitating the rapid acquisition of the initial structural parameters of the hybrid beam.

[0040] In some optional embodiments, the adjustment of the mid-span related structural parameters of the hybrid beam is consistent with that of the concrete beam, including: Adjust the side span, top beam height of the middle pier, web thickness, and top and bottom plate thickness of the hybrid beam to be consistent with those of the concrete beam.

[0041] In this embodiment, the structural parameters related to the mid-span of the hybrid beam are adjusted to be consistent with those of the concrete beam. This includes adjusting the side spans, the height of the beam at the mid-pier, the web thickness, and the thickness of the top and bottom slabs of the hybrid beam to be consistent with those of the concrete beam. There is an inherent mechanical relationship between parameters such as the side spans, the height of the beam at the mid-pier, the web thickness, and the thickness of the top and bottom slabs. By adjusting these parameters as a whole to be consistent with the concrete beam, the coordination and consistency of the dimensions of each part of the hybrid beam are ensured, avoiding unreasonable structural stress caused by adjusting a single parameter, and making the overall mechanical behavior of the hybrid beam more in line with engineering practice.

[0042] On the other hand, this application also provides a hybrid beam bridge, which is constructed using the above-described hybrid beam bridge design method.

[0043] When using this hybrid beam bridge design method, the initial structural parameters of the hybrid beam and concrete beam under the same conditions are first obtained based on the relevant design specifications for steel-concrete composite bridges and prestressed concrete beams. Then, the mid-span of the concrete beam is adjusted to make the maximum bending moment at the top of the pier equal in the structural parameters of the concrete beam and the hybrid beam. The mid-span-related structural parameters of the hybrid beam are adjusted to be consistent with those of the concrete beam, and the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is obtained. If the change in the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is greater than or equal to a set threshold, the structural parameters of the concrete beam are adjusted to make the maximum bending moment at the top of the pier equal to that after the hybrid beam parameters are adjusted. The mid-span-related structural parameters of the hybrid beam are then adjusted to be consistent with those of the concrete beam after the parameter update, until the change in the maximum bending moment at the top of the pier after the hybrid beam parameters are adjusted is less than the set threshold. By linking the design of hybrid beam bridges with that of concrete beam bridges, and through iterative adjustments to make the hybrid beams and concrete beams approach each other in key parameters such as the maximum bending moment at the top of the pier, the safety reserve of the hybrid beam structure is ensured to be comparable to that of a mature concrete beam bridge. This facilitates rapid design of hybrid beam bridges and solves the problem that in existing technologies, finite element analysis results are highly dependent on model assumptions and boundary conditions, making it difficult for designers lacking engineering experience to accurately grasp key parameters. Furthermore, analogical design methods, due to a lack of sufficient successful cases for reference, struggle to coordinate the reasonable location of the steel-concrete composite section with the span of the side spans and the height of the main beams to complete multi-parameter coupled optimization.

[0044] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0045] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A design method for hybrid beam bridges, characterized in that, include: Based on the relevant design specifications for steel-concrete composite bridges and prestressed concrete beams, the initial structural parameters of the composite beams and concrete beams under the same conditions were obtained. Adjust the mid-span of the concrete beam to make the maximum bending moment at the top of the pier equal in the structural parameters of the concrete beam and the hybrid beam. Adjust the mid-span related structural parameters of the hybrid beam to be consistent with those of the concrete beam, and obtain the maximum bending moment at the top of the mid-pier after the parameters of the hybrid beam are adjusted; If the change in the maximum bending moment at the top of the pier after the adjustment of the hybrid beam parameters is greater than or equal to a set threshold, the structural parameters of the concrete beam are adjusted so that the maximum bending moment at the top of the pier of the concrete beam is equal to the maximum bending moment at the top of the pier after the adjustment of the hybrid beam parameters. The mid-span related structural parameters of the hybrid beam are then adjusted to be consistent with those of the concrete beam after the parameter update, until the change in the maximum bending moment at the top of the pier after the adjustment of the hybrid beam parameters is less than the set threshold.

2. The hybrid beam bridge design method as described in claim 1, characterized in that, The adjustment of the structural parameters of the concrete beam, and the making the maximum bending moment at the top of the pier of the concrete beam equal to the maximum bending moment at the top of the pier of the hybrid beam after parameter adjustment, includes: Based on the adjusted mid-span of the concrete beam, adjust the structural parameters associated with the mid-span of the concrete beam. The mid-span of the concrete beam is adjusted again so that the maximum bending moment at the top of the middle pier of the concrete beam is equal to the maximum bending moment at the top of the middle pier of the hybrid beam after parameter adjustment.

3. The hybrid beam bridge design method as described in claim 1, characterized in that, After adjusting the mid-span of the concrete beam, the method further includes: Determine whether the mid-span of the adjusted concrete beam is greater than the set span of the concrete beam; If not, proceed to the next step; If so, adjust the mid-span of the concrete beam to the set span of the concrete beam, obtain the maximum bending moment at the top of the middle pier in the structural parameters of the concrete beam, adjust the mid-span associated structural parameters of the hybrid beam to be consistent with those of the concrete beam, and increase the length of the mid-span steel beam in the structural parameters of the hybrid beam until the difference between the maximum bending moment at the top of the middle pier in the structural parameters of the hybrid beam and the maximum bending moment at the top of the middle pier in the structural parameters of the concrete beam is less than a set threshold.

4. A hybrid beam bridge design method as described in claim 1 or 3, characterized in that, After the hybrid beam parameters are adjusted, the following is also included: A set prestress is applied to the adjusted concrete beam to make the concrete beam bear force in accordance with the specification requirements, and the maximum principal tensile stress of the concrete beam and the vertical deflection at the steel-concrete interface caused by shrinkage and creep are obtained. Adjust the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam, and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep, are both less than the preset values.

5. The hybrid beam bridge design method as described in claim 4, characterized in that, If the conditions are not met after adjusting the prestress applied to the hybrid beam: Adjust the height of the top beam of the middle pier of the hybrid beam, and readjust the prestress applied to the hybrid beam until the difference between the maximum principal tensile stress of the concrete in the hybrid beam and the concrete beam and the difference between the vertical deflection at the steel-concrete interface caused by shrinkage and creep are both less than the preset values.

6. The hybrid beam bridge design method as described in claim 5, characterized in that, The adjustment of the height of the top beam of the middle pier of the hybrid beam includes: The height of the top beam of the middle pier of the hybrid beam is increased in increments of 0.1m.

7. The hybrid beam bridge design method as described in claim 1, characterized in that, When obtaining the maximum bending moment at the top of the middle pier of the hybrid beam structure parameters: Based on the bending moment envelope diagram of the hybrid beam, the point of zero maximum bending moment is obtained; Adjust the steel-concrete interface to the zero point of maximum bending moment to obtain the maximum bending moment at the top of the middle pier.

8. The hybrid beam bridge design method as described in claim 1, characterized in that, When obtaining the initial structural parameters of the hybrid beam: Based on navigation and flood control design requirements, the main span is obtained; Based on the main span, the structural parameters associated with the mid-span of the hybrid beam are obtained.

9. The hybrid beam bridge design method as described in claim 1, characterized in that, The adjustment of the mid-span related structural parameters of the hybrid beam to be consistent with those of the concrete beam includes: Adjust the side span, top beam height of the middle pier, web thickness, and top and bottom plate thickness of the hybrid beam to be consistent with those of the concrete beam.

10. A hybrid beam bridge, characterized in that, Constructed using a hybrid beam bridge design method as described in any one of claims 1-9.

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