Fabricated steel formwork welding method and system for steel-concrete superposed beam bridge floor maintenance path

Abstract

The invention relates to the technical field of welding, in particular to an assembly type steel formwork welding method and system for a steel-concrete composite beam bridge floor maintenance way, and the method comprises the steps that the edge of a steel formwork is in lap joint with the top of the edge of a main beam of a steel-concrete composite beam bridge; welding is conducted on the edge area, where the binding face is formed, of the steel formwork; vertical steel bars are welded to the edge of the top of the main beam, the vertical steel bars and the steel formwork are connected through first cable-stayed steel bars, the vertical steel bars and the main beam are connected through second cable-stayed steel bars, and the laying process of the cable-stayed steel bars comprises the steps that a coupling model is established, and concrete flow state side pressure is applied; and generating an optimal layout path of the cable-stayed steel bars through topological optimization, wherein an objective function is to minimize the mid-span deflection of the steel template. According to the invention, the problems of low positioning precision, poor hole position adaptation and the like in a reinforcing body system of a traditional template technology can be effectively solved, and the construction quality of a reinforced concrete superposed beam bridge floor maintenance path can be ensured.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a welding method and system for prefabricated steel formwork for the maintenance access road of a steel-concrete composite beam bridge. Background Technology

[0002] The inspection walkway on the deck of a steel-concrete composite beam bridge is an important auxiliary structure, specifically designed for bridge inspection, maintenance, and upkeep. For example... Figure 1 and 2 As shown, the steel-concrete composite beam bridge includes a main beam 1 set along the length of the bridge. After the edge of the main beam 1 is connected to the steel structure of the steel-concrete composite beam bridge deck maintenance walkway through the plate structure 11, concrete is poured together on the top of the main beam 1 and the maintenance walkway. For this purpose, shear studs 2 are pre-welded to the top of the main beam.

[0003] After the concrete is poured, the steel-concrete composite beam bridge deck maintenance walkway works in conjunction with the main beam 1 and the reinforced concrete bridge deck, giving full play to the tensile strength of steel and the compressive strength of concrete. The cast-in-place concrete technology can ensure integrity and durability.

[0004] Currently, in the construction of the maintenance walkway of the steel-concrete composite beam bridge, traditional formwork technology is often used to fix the steel formwork to the main beam of the steel-concrete composite beam bridge through connectors. The reinforcement system obtained by this process often has problems such as low positioning accuracy and poor hole matching. Insufficient bolt pre-tightening can lead to misalignment, and increased construction vibration can also loosen the connection points, thus posing a risk of collapse. Summary of the Invention

[0005] This invention provides a method and system for welding prefabricated steel formwork for the maintenance access road of a steel-concrete composite beam bridge, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge deck includes: The edges of the steel formwork are overlapped with the top edge of the main beam of the steel-concrete composite beam bridge to form a fitting surface; Welding establishes a fixed connection between the steel formwork and the main beam; Vertical reinforcing bars are welded to the top edge of the main beam, and the vertical reinforcing bars are connected to the steel formwork by a first diagonal reinforcing bar, and the vertical reinforcing bars are connected to the main beam by a second diagonal reinforcing bar; The process of laying the inclined reinforcing bars includes: Establish a coupled model of steel formwork-main beam-triangular anchorage unit; Apply lateral pressure to the concrete flow state in the coupled model; The optimal placement path for the inclined reinforcing bars is generated through topology optimization, and the objective function is to minimize the mid-span deflection of the steel formwork.

[0007] Furthermore, a coupled model of steel formwork-main beam-triangular anchorage unit is established, including: Create a three-dimensional geometric model of the steel formwork, the plate structure at the edge of the main beam, the vertical reinforcement, the first diagonal reinforcement and the second diagonal reinforcement, and parameterize the position, angle and spacing of the diagonal reinforcement in the initial model; Set material properties for each structure and define connection relationships; The coupled model is then meshed using the finite element method.

[0008] Furthermore, establishing a coupled model of steel formwork-main beam-triangular anchorage unit also includes: Create a static analysis step, apply the structural self-weight load, and run the preliminary analysis; The model was validated based on the execution results.

[0009] Furthermore, the optimal placement path for the inclined tie bars is generated through topology optimization, including: The concrete flow lateral pressure load is mapped into an equivalent nodal force matrix, and the load application points that contribute more than a set threshold to the mid-span deflection are identified as key driving points. The topology optimization includes generating an initial reinforcement population at the location of the concrete flow lateral pressure using a global random search algorithm, and selecting a seed scheme with the optimal mid-span deflection value, wherein the key driving point is given priority search authority; it also includes performing fine-grained iteration of node positions on the seed scheme based on displacement sensitivity gradient, wherein the sensitivity gradient resolution of the neighborhood of the key driving point is automatically improved. The optimization is terminated when the mid-span deflection decrease is less than the first set value and the maximum equivalent stress change rate of the reinforcing steel is less than the second set value during continuous iteration.

[0010] Furthermore, each population in the initial reinforcement population represents a complete set of spatial configurations of inclined reinforcing bars, including: the spatial coordinate set of connection points of the reinforcing bars on the steel formwork, main beam, and vertical reinforcing bars, and the direction of the spatial polyline segment defined by the sequence of connection points; An initial reinforcement population is generated at the location of the lateral pressure in the concrete flow state using a global random search algorithm, including: The spatial coordinate set of the connection points is randomly sampled, and feasible reinforcement paths are automatically generated based on the direction of the spatial polyline segments through kinematic constraint rules. Each path satisfies the minimum construction feasibility condition.

[0011] Furthermore, the seed scheme is subjected to fine-tuning iteration of node positions based on the displacement sensitivity gradient, including: Calculate the global displacement sensitivity matrix; The mesh of the neighborhood of the key driving point is ultra-fine: Update the spatial coordinate set of the connection points along the negative gradient direction: The spatial coordinate set of the connection points is updated by applying process constraints.

[0012] The prefabricated steel formwork welding system for the maintenance walkway of a steel-concrete composite beam bridge deck includes: The template positioning welding unit overlaps the edge of the steel template with the top edge of the main beam of the steel-concrete composite beam bridge to form a fitting surface, and welds to establish a fixed connection between the steel template and the main beam; The triangular anchorage unit includes a vertical steel bar welded to the top edge of the main beam, a first diagonal steel bar connecting the vertical steel bar to the steel formwork, and a second diagonal steel bar connecting the vertical steel bar to the main beam. Topology optimization control unit, including: The coupled modeling module constructs a coupled model of steel formwork, main beam, and triangular anchorage unit. The load loading module applies lateral pressure of concrete flow to the coupled model; The path planning module generates the optimal layout path for the inclined steel reinforcement by minimizing the mid-span deflection of the steel formwork as the topology optimization objective.

[0013] Furthermore, The load loading module includes: The load mapping submodule maps the concrete flow lateral pressure load into an equivalent nodal force matrix. The driving point identification submodule identifies load application points that contribute more than a set threshold to the mid-span deflection as key driving points. The path planning module includes: The population generation submodule uses a global random search algorithm to generate an initial reinforcement population at the location of the concrete flow lateral pressure and assigns priority search permissions to key driving points. The scheme selection submodule evaluates the mid-span deflection value of each scheme in the initial reinforcement group and selects the optimal seed scheme. The gradient iteration submodule performs fine-grained iteration of the node positions of the seed scheme based on the displacement sensitivity gradient, and automatically improves the sensitivity gradient resolution in the neighborhood of key driving points. The convergence determination submodule terminates the optimization when the mid-span deflection decrease is less than the first set value and the maximum equivalent stress change rate of the steel reinforcement is less than the second set value during continuous iteration.

[0014] Furthermore, when the population generation submodule generates the initial reinforcement population, each population represents a complete set of spatial configurations of the inclined steel bars, including: the spatial coordinate set of connection points of the steel bars on the steel formwork, main beam, and vertical steel bars, and the direction of the spatial polyline segment defined by the sequence of connection points; The population generation submodule is configured to randomly sample the spatial coordinate set of the connection points and automatically generate feasible rebar paths that meet the minimum construction feasibility conditions through kinematic constraint rules.

[0015] Furthermore, the gradient iteration submodule includes: Sensitivity calculation unit calculates the global displacement sensitivity matrix; A mesh refinement unit is used to refine the finite element mesh in the neighborhood of the key driving point. The coordinate update unit updates the spatial coordinate set of the connection points along the negative gradient direction; The process correction unit corrects and updates the spatial coordinate set of connection points by applying process constraints.

[0016] The technical solution of this invention can achieve the following technical effects: This invention can effectively solve the problems of low positioning accuracy and poor hole matching in the reinforcement system of traditional template technology, and can ensure the construction quality of the inspection road of steel-concrete composite beam bridge deck. Attached Figure Description

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

[0018] Figure 1 This is a top view of a steel-concrete composite beam bridge. Figure 2 for Figure 1 Sectional view at point AA; Figure 3 and Figure 4 These are schematic diagrams showing the completed welding of the steel formwork relative to the main beam at different angles. Figure 5 This is a flowchart of the process of laying out the inclined reinforcing bars in Example 1; Figure 6 A flowchart for establishing a coupled model of steel formwork-main beam-triangular anchorage unit; Figure 7 A flowchart for generating the optimal placement path of diagonal reinforcing bars through topology optimization; Figure 8 This is a flowchart illustrating the process of refining the node positions of the seed scheme based on the displacement sensitivity gradient. Attached reference numerals: 1. Main beam; 11. Slab structure; 2. Shear stud; 3. Steel formwork; 31. First steel plate; 32. Second steel plate; 4. Fitting surface; 5. Vertical reinforcement; 6. First diagonal reinforcement; 7. Second diagonal reinforcement. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Example 1 like Figures 3-5 As shown, the welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge includes: A1: The edge of the steel formwork 3 is overlapped with the top edge of the main beam 1 of the steel-concrete composite beam bridge, specifically the top edge of the plate structure 11 shown in the figure, to form a bonding surface 4. A2: Welding is performed on the edge area of ​​the steel formwork 3 that forms the mating surface 4 to establish a fixed connection between the steel formwork 3 and the main beam 1; A3: Weld vertical reinforcing bars 5 to the top edge of the main beam 1. To ensure the stability of the vertical reinforcing bars 5, as follows: Figure 4 As shown, the vertical reinforcing bars 5 and shear studs 2 can be fixedly connected simultaneously, specifically by welding or binding; the vertical reinforcing bars 5 and the steel formwork 3 are connected by the first diagonal reinforcing bar 6, and the vertical reinforcing bars 5 and the main beam 1 are connected by the second diagonal reinforcing bar 7. The process of laying the diagonal reinforcing bars includes: A31: Establish a coupled model of steel formwork-main beam-triangular anchorage unit; A32: Apply concrete flow lateral pressure in the coupled model; the concrete flow lateral pressure in this step refers to the dynamic fluid pressure generated on the steel formwork 3 by the uncured concrete during the pouring and vibration process. It is only applied to the inner side of the steel formwork 3 in contact with the concrete, and there is no load on the outer side. The load direction is perpendicular to the formwork surface and points outward. A33: The optimal placement path for the inclined reinforcing bars is generated through topology optimization, with the objective function being to minimize the mid-span deflection of the steel formwork. In this embodiment, the mid-span deflection location is defined as the geometric center of the overall projected profile of the steel formwork 3, which includes, as shown in the figure... Figure 4 The first steel plate 31 and the second steel plate 32 shown have their geometric centers located on the first steel plate 31. Under the action of the lateral pressure of the concrete flow state, the mid-span deflection is the normal displacement vector generated by this geometric center. In this embodiment, it is the displacement component of the overall initial design plane of the first steel plate 31 in the vertical figure.

[0021] As a preferred embodiment of the above, such as Figure 6 As shown, in step A31, a coupled model of steel formwork-main beam-triangular anchorage unit is established, including: A311: Create a 3D geometric model of the steel formwork 3, the plate structure 11 at the edge of the main beam 1, the vertical reinforcement 5, the first diagonal reinforcement 6, and the second diagonal reinforcement 7. Parametrically set the position, angle, and spacing of the diagonal reinforcement in the initial model. This step needs to be performed according to the design drawings. Finite element preprocessing software such as ANSYS can be used. During the implementation, it is necessary to ensure the accuracy of the relative positions between the components. Parametric settings can facilitate subsequent optimization and adjustment. A312: Set material properties for each structure and define connection relationships; Specifically, in this step, linear elastic material properties, including elastic modulus, Poisson's ratio, and density, are assigned to the steel formwork 3, the slab structure 11, the vertical reinforcing bars 5, the first diagonal reinforcing bar 6, and the second diagonal reinforcing bar 7, respectively. During the connection definition process, the steel formwork 3 is overlapped at the edge of the top of the slab structure 11 of the main beam 1, and the welding effect is simulated through node coupling or binding contact to define that there is no relative displacement or rotation here. The bottom node of the vertical reinforcing bar 5 is coupled to the corresponding node at the top of the main beam 1 to simulate welding fixation. The two ends of the first diagonal reinforcing bar 6 are coupled to the nodes on the steel formwork 3 and the vertical reinforcing bar 5, respectively, and the two ends of the second diagonal reinforcing bar 7 are coupled to the nodes on the main beam 1 and the vertical reinforcing bar 5, respectively, also simulating welding fixation.

[0022] In addition to the above-mentioned connection relationships, constraints also need to be established. Given the large span and sufficient stiffness of the main beam 1 structure in this embodiment, the load in the maintenance access area has minimal impact on the overall deformation of the main beam 1. Therefore, this step only constrains the rigid displacement of the main beam 1, allowing it to undergo elastic deformation under load. Specifically, at the end of the main beam 1 furthest from the maintenance access, usually near the pier or fixed support, all translational degrees of freedom are constrained. In some embodiments, the longitudinal constraint can be relaxed. At the end of the main beam 1 closest to the maintenance access, at least lateral translation is constrained to prevent lateral displacement, and rotation around the vertical axis is constrained to prevent torsion. The above constraints are suitable for the situation in this embodiment where the stiffness of the main beam 1 is much greater than that of the maintenance access formwork system, and the impact of the maintenance access load on the overall deformation of the main beam 1 is negligible, making the implementation process simpler. As for the steel formwork 3, since the overlapping surfaces have been welded and fixed, the bottom has already been constrained. A313: Perform finite element mesh generation on the coupled model. In this step, the plate structure 11 of the steel formwork 3 and main beam 1 is discretized using shell elements, focusing on stress in the thickness direction; the vertical reinforcing bars 5, the first diagonal reinforcing bar 6, and the second diagonal reinforcing bar 7 are discretized using beam or rod elements, ensuring correct element orientation; the mesh must be sufficiently refined at coupling nodes or connection areas to accurately transfer loads. A relatively fine mesh is used in stress concentration areas, while a relatively coarse mesh can be used in other areas to balance computational efficiency.

[0023] After completing steps A311 to A313 above, preferably, establishing the coupled model of steel formwork-main beam-triangular anchorage unit further includes: A314: Create a static analysis step, apply the structural self-weight load, and run the preliminary analysis; the static analysis step can simulate the quasi-equilibrium state of the structure under its own weight. During the application of the self-weight load, the load needs to be applied to all components. A315: Verify the model based on the running results. This step includes verification of at least: whether the model solution converges, whether there are unreasonable rigid body displacements, whether the mesh connections are stable, and whether the displacement and stress values ​​of steel formwork 3 are within a reasonable range. Specifically, verification must meet the following requirements: no errors or interruption warnings during the model solution process, a smooth decrease in the iterative residual curve to within the tolerance, deformation modes meeting expectations, no mesh penetration or separation, continuous stress at connections, and reasonable deflection and material stress of steel formwork 3.

[0024] As a preferred embodiment of the above, such as Figure 7 As shown, the optimal placement path for the inclined tie bars is generated through topology optimization, including: A331: Map the concrete flow lateral pressure load to an equivalent nodal force matrix, and identify the load application points whose contribution to mid-span deflection is greater than a set threshold as key driving points; In this step, the purpose of key driving point identification is to quantify the deflection contribution efficiency of each load application point by solving the variational response of mid-span deflection under unit load based on load-displacement transfer path analysis. In this embodiment, the threshold is set as the regional average value, that is, the points whose contribution efficiency is greater than the regional average value are identified as key driving points; A332: Perform topology optimization, including generating an initial reinforcement population at the location of the concrete flow lateral pressure using a global random search algorithm, and selecting the seed scheme with the optimal mid-span deflection value, where key driving points are given priority search authority; it also includes fine-tuning the node positions of the seed scheme based on displacement sensitivity gradient, where the sensitivity gradient resolution of the neighborhood of key driving points is automatically improved. During the implementation of this step, each population in the initial reinforcement population represents a complete set of spatial configurations of the inclined reinforcement, including: the spatial coordinate set of the connection points of the reinforcement on the steel formwork 3, the main beam 1, and the vertical reinforcement 5, which is a geometric topological feature; and the direction of the spatial polyline segment defined by the sequence of connection points, which is a path morphology feature, that is, including implicit angle and curvature attributes. An initial reinforcement population is generated at the location of the lateral pressure of the concrete flow state using a global random search algorithm. This includes: randomly sampling the spatial coordinate set of connection points, and automatically generating feasible reinforcement paths based on the spatial polyline segment direction through kinematic constraint rules. Each path satisfies the minimum construction feasibility condition, such as the reinforcement not crossing physical obstacles.

[0025] In large bridge maintenance walkway formwork systems, the distribution of concrete lateral pressure loads exhibits high spatial non-uniformity. Traditional optimization algorithms, by indiscriminately traversing all load application points, result in a significant proportion of computational resources being consumed in inefficient regions, such as low-deformation-sensitive areas near constraint ends. Furthermore, they struggle to capture local high-pressure areas, such as the nonlinear coupling effect between the vibratory compaction point and mid-span deflection. In this optimized scheme, key driving points are given priority in search, increasing the probability of generating candidate reinforcement schemes in the neighborhood of these key driving points during the global search phase. By forcibly exploring high-potential areas, the algorithm avoids getting trapped in locally suboptimal solutions dominated by secondary load points.

[0026] Furthermore, in this step, during the fine-tuning iteration of node positions for the seed scheme based on the displacement sensitivity gradient, the input is the spatial coordinate set of the connection points of the selected seed scheme, and the output is the optimized spatial coordinate set of the connection points, such as... Figure 8 As shown, it includes: S1: Calculate the global displacement sensitivity matrix; through structural response inversion analysis, quantify the sensitivity of the steel formwork mid-span deflection to unit changes in the spatial coordinates of each connection point. This matrix reveals the contribution efficiency of node adjustments at different locations to the overall stiffness, providing a directional basis for coordinate updates. S2: Refine the mesh in the neighborhood of the key driving point: By increasing the number of finite element elements in the local area, the resolution of displacement field calculation is significantly improved, thereby automatically improving the sensitivity gradient resolution in the neighborhood of the key driving point. Specifically, by dynamically refining the finite element mesh density in the area around the key driving point with high load contribution, and controlling the density intensity to be positively correlated with the load contribution, the gradient calculation accuracy is improved, and the misjudgment of the optimization direction due to the coarse mesh is avoided. S3: Update the spatial coordinate set of the connection points along the negative gradient direction: Specifically, based on the fastest deflection path indicated by the sensitivity matrix, adjust the coordinate positions of the connection points proportionally, and the update step size can be adaptively controlled to ensure that each iteration effectively reduces the mid-span deflection value and gradually approaches the local optimum. S4: Update the spatial coordinate set of connection points by applying process constraints.

[0027] During the implementation of step S4, the processing constraints may include at least one of the following: bending process constraints, ensuring that the radius of curvature of the rebar path is not less than 5 times the diameter to meet the requirements of cold bending construction; or, spatial obstacle avoidance constraints, eliminating the risk of collision between the rebar and shear stud 2 or adjacent rebars through geometric interference detection. Of course, the above constraints are only some examples of constraints and are not intended to limit the scope of protection of this invention.

[0028] The process of generating the optimal placement path for inclined tie bars through topology optimization also includes: A333: Optimization terminates when the mid-span deflection decrease is less than the first set value and the maximum equivalent stress change rate of the reinforcing steel is less than the second set value during continuous iterations. The first and second set values ​​are system-defined values ​​that can be adjusted according to actual working conditions.

[0029] Example 2 The prefabricated steel formwork welding system for the maintenance walkway of a steel-concrete composite beam bridge deck includes: The template positioning welding unit overlaps the edge of the steel template with the top edge of the main beam of the steel-concrete composite beam bridge to form a fitting surface, and welds to establish a fixed connection between the steel template and the main beam; The triangular anchorage unit includes a vertical steel bar welded to the top edge of the main beam, a first diagonal tie bar connecting the vertical steel bar to the steel formwork, and a second diagonal tie bar connecting the vertical steel bar to the main beam. Topology optimization control unit, including: The coupled modeling module constructs a coupled model of steel formwork, main beam, and triangular anchorage unit; the load loading module applies lateral pressure of concrete flow to the coupled model; and the path planning module generates the optimal placement path of the inclined steel reinforcement with the goal of minimizing the mid-span deflection of the steel formwork.

[0030] The welding system in this embodiment can achieve the same technical effect as in Embodiment 1, which will not be repeated here.

[0031] As a preferred embodiment, and also to address the problem caused by the indiscriminate traversal of all load application points in traditional optimization algorithms, the load loading module includes: The load mapping submodule maps the lateral pressure load of concrete flow into an equivalent nodal force matrix; the driving point identification submodule identifies load application points that contribute more than a set threshold to the mid-span deflection as key driving points. Based on the above optimizations, the path planning module includes: The population generation submodule uses a global random search algorithm to generate an initial reinforcement population at the location of the concrete flow lateral pressure and assigns priority search permissions to key driving points, thereby increasing the generation probability of candidate reinforcement schemes in the neighborhood of key driving points during the global search phase. The scheme selection submodule evaluates the mid-span deflection value of each scheme in the initial reinforcement population and selects the optimal seed scheme. The gradient iteration submodule performs fine-grained iteration on the node positions of the seed scheme based on the displacement sensitivity gradient and automatically improves the sensitivity gradient resolution in the neighborhood of key driving points. The convergence judgment submodule terminates the optimization when the mid-span deflection decrease is less than a first set value and the maximum equivalent stress change rate of the reinforcement is less than a second set value during continuous iteration.

[0032] In this embodiment, when the population generation submodule generates the initial reinforcement population, each population represents a complete set of spatial configurations of the inclined reinforcement, including: the spatial coordinate set of connection points of the reinforcement on the steel formwork, main beam, and vertical reinforcement, and the direction of the spatial polyline segment defined by the sequence of connection points; correspondingly, the population generation submodule is configured to randomly sample the spatial coordinate set of connection points and automatically generate feasible reinforcement paths that meet the minimum construction feasibility conditions through kinematic constraint rules.

[0033] As a preferred embodiment, the gradient iteration submodule includes: The sensitivity calculation unit reveals the contribution efficiency of node adjustments at different locations to the overall stiffness and calculates the global displacement sensitivity matrix. The mesh refinement unit is used to refine the finite element mesh in the neighborhood of the key driving point; similarly, by increasing the number of finite element elements in the local area, the sensitivity gradient resolution of the neighborhood of the key driving point is automatically improved. The coordinate update unit updates the spatial coordinate set of the connection points along the negative gradient direction; The process correction unit corrects and updates the spatial coordinate set of connection points by applying process constraints.

[0034] The technical effects achieved by the above preferred solutions are the same as those described in Embodiment 1, and will not be repeated here.

[0035] This invention replaces traditional bolt connections with welded and fixed triangular anchoring units, eliminating the risks of hole machining errors and preload failure. Based on precise mapping of concrete flow lateral pressure and key driving point identification technology, it generates the optimal placement path for inclined reinforcing bars through topology optimization, improving the efficiency of reinforcing bar load transfer and systematically eliminating the risk of collapse. During implementation, parametric coupling modeling and kinematic constraint rules are combined to automatically generate the required spatial configuration of reinforcing bars, avoiding positioning deviations caused by manual reinforcement placement. Through displacement sensitivity gradient iteration and process constraint correction, the mesh resolution of key areas is dynamically improved. Based on these advantages, the construction quality of the maintenance walkway on the steel-concrete composite beam bridge deck is effectively improved.

[0036] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge deck, characterized in that, include: The edges of the steel formwork are overlapped with the top edge of the main beam of the steel-concrete composite beam bridge to form a fitting surface; Welding establishes a fixed connection between the steel formwork and the main beam; Vertical reinforcing bars are welded to the top edge of the main beam, and the vertical reinforcing bars are connected to the steel formwork by a first diagonal reinforcing bar, and the vertical reinforcing bars are connected to the main beam by a second diagonal reinforcing bar; The process of laying the inclined reinforcing bars includes: Establish a coupled model of steel formwork-main beam-triangular anchorage unit; Apply lateral pressure to the concrete flow state in the coupled model; The optimal placement path for the inclined reinforcing bars is generated through topology optimization, with the objective function being to minimize the mid-span deflection of the steel formwork.

2. The welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 1, characterized in that, Establish a coupled model of steel formwork-main beam-triangular anchorage element, including: Create a three-dimensional geometric model of the steel formwork, the plate structure at the edge of the main beam, the vertical reinforcement, the first diagonal reinforcement and the second diagonal reinforcement, and parameterize the position, angle and spacing of the diagonal reinforcement in the initial model; Set material properties for each structure and define connection relationships; The coupled model is then meshed using the finite element method.

3. The welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 2, characterized in that, The establishment of a coupled model of steel formwork-main beam-triangular anchorage element also includes: Create a static analysis step, apply the structural self-weight load, and run the preliminary analysis; The model was validated based on the execution results.

4. The welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 1, characterized in that, The optimal placement path for the inclined tie bars is generated through topology optimization, including: The concrete flow lateral pressure load is mapped into an equivalent nodal force matrix, and the load application points that contribute more than a set threshold to the mid-span deflection are identified as key driving points. The topology optimization includes generating an initial reinforcement population at the location of the concrete flow lateral pressure using a global random search algorithm, and selecting a seed scheme with the optimal mid-span deflection value, wherein the key driving point is given priority search authority; it also includes performing fine-grained iteration of node positions on the seed scheme based on displacement sensitivity gradient, wherein the sensitivity gradient resolution of the neighborhood of the key driving point is automatically improved. The optimization is terminated when the mid-span deflection decrease is less than the first set value and the maximum equivalent stress change rate of the reinforcing steel is less than the second set value during continuous iteration.

5. The method for welding prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge according to claim 4, characterized in that, Each population in the initial reinforcement group represents a complete set of spatial configurations of inclined steel bars, including: the set of spatial coordinates of the connection points of the steel bars on the steel formwork, main beam, and vertical steel bars, and the direction of the spatial polyline segment defined by the sequence of connection points; An initial reinforcement population is generated at the location of the lateral pressure in the concrete flow state using a global random search algorithm, including: The spatial coordinate set of the connection points is randomly sampled, and feasible reinforcement paths are automatically generated based on the direction of the spatial polyline segments through kinematic constraint rules. Each path satisfies the minimum construction feasibility condition.

6. The welding method for prefabricated steel formwork for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 5, characterized in that, The seed scheme is subjected to fine-tuning iteration of node positions based on displacement sensitivity gradient, including: Calculate the global displacement sensitivity matrix; The mesh of the neighborhood of the key driving point is ultra-fine: Update the spatial coordinate set of the connection points along the negative gradient direction: The spatial coordinate set of the connection points is updated by applying process constraints.

7. A prefabricated steel formwork welding system for the maintenance walkway of a steel-concrete composite beam bridge deck, characterized in that, include: The template positioning welding unit overlaps the edge of the steel template with the top edge of the main beam of the steel-concrete composite beam bridge to form a fitting surface, and welds to establish a fixed connection between the steel template and the main beam; The triangular anchorage unit includes a vertical steel bar welded to the top edge of the main beam, a first diagonal steel bar connecting the vertical steel bar to the steel formwork, and a second diagonal steel bar connecting the vertical steel bar to the main beam. Topology optimization control unit, including: The coupled modeling module constructs a coupled model of steel formwork, main beam, and triangular anchorage unit. The load loading module applies lateral pressure of concrete flow to the coupled model; The path planning module generates the optimal layout path for the inclined steel reinforcement by minimizing the mid-span deflection of the steel formwork as the topology optimization objective.

8. The prefabricated steel formwork welding system for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 7, characterized in that, The load loading module includes: The load mapping submodule maps the concrete flow lateral pressure load into an equivalent nodal force matrix. The driving point identification submodule identifies load application points that contribute more than a set threshold to the mid-span deflection as key driving points. The path planning module includes: The population generation submodule uses a global random search algorithm to generate an initial reinforcement population at the location of the concrete flow lateral pressure and assigns priority search permissions to key driving points. The scheme selection submodule evaluates the mid-span deflection value of each scheme in the initial reinforcement group and selects the optimal seed scheme. The gradient iteration submodule performs fine-grained iteration of the node positions of the seed scheme based on the displacement sensitivity gradient, and automatically improves the sensitivity gradient resolution in the neighborhood of key driving points. The convergence determination submodule terminates the optimization when the mid-span deflection decrease is less than the first set value and the maximum equivalent stress change rate of the steel reinforcement is less than the second set value during continuous iteration.

9. The prefabricated steel formwork welding system for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 8, characterized in that, When the population generation submodule generates the initial reinforcement population, each population represents a complete set of diagonal reinforcement spatial configurations, including: the spatial coordinate set of connection points of the reinforcement on the steel formwork, main beam, and vertical reinforcement, and the direction of the spatial polyline segment defined by the connection point sequence; The population generation submodule is configured to randomly sample the spatial coordinate set of the connection points and automatically generate feasible rebar paths that meet the minimum construction feasibility conditions through kinematic constraint rules.

10. The prefabricated steel formwork welding system for the maintenance walkway of a steel-concrete composite beam bridge deck according to claim 9, characterized in that, The gradient iteration submodule includes: Sensitivity calculation unit calculates the global displacement sensitivity matrix; A mesh refinement unit is used to refine the finite element mesh in the neighborhood of the key driving point. The coordinate update unit updates the spatial coordinate set of the connection points along the negative gradient direction; The process correction unit corrects and updates the spatial coordinate set of connection points by applying process constraints.

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