A bridge construction safety risk dynamic early warning method and system based on BIM

Abstract

The application discloses a kind of bridge construction safety risk dynamic early warning method and system based on BIM, method includes: generating time-varying structure topology graph sequence;Based on time-varying structure topology graph sequence and real-time acquisition construction monitoring data, form key risk component set;Local stress evolution model is built, and the stress state and stability coefficient of each component are predicted;Based on the stability coefficient calculated between each component risk coupling intensity predicted each component;Simulate the failure chain effect of each component, calculate the dynamic instability probability of bridge;Set different classification early warning threshold, according to dynamic instability probability triggers corresponding grade bridge instability early warning, generates optimization control strategy.System includes: time-varying topology generation module, risk component identification module, stress evolution prediction module, coupling strength calculation module, instability probability calculation module, early warning strategy generation module.The application solves the problem of traditional bridge construction safety management, and provides reliable technical support for bridge construction safety.

Description

Technical Field

[0001] This invention relates to the field of bridge construction safety management, specifically to a BIM-based dynamic early warning method and system for bridge construction safety risks. Background Technology

[0002] As bridge engineering develops towards larger spans and more complex structures, safety risk management during construction has become a core technical requirement for ensuring project quality and personnel safety.

[0003] Currently, traditional bridge construction safety management methods struggle to accurately assess the dynamic evolution of component risks during construction, typically relying on static analysis or post-construction measures. This leads to insufficient foresight regarding potential cascading failures, failing to proactively mitigate safety hazards and significantly increasing safety management costs and the probability of accidents during the construction phase. Therefore, there is an urgent need to develop a new BIM-based dynamic early warning method and system for bridge construction safety risks. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a BIM-based dynamic early warning method and system for bridge construction safety risks. This improves upon the current situation where traditional bridge construction safety management relies on static assessments or post-event remedies, lacks prediction of the correlation and evolution trends of potential risks, and results in delayed and insufficiently targeted safety early warnings.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A BIM-based dynamic early warning method for bridge construction safety risks is provided, which includes the following steps:

[0007] S1: Obtain the BIM 3D structural model of the bridge construction and generate a time-varying structural topology sequence based on the construction schedule information to reflect the dynamic changes of completed components, temporary support components and connection relationships in each construction stage.

[0008] S2: Based on the time-varying structural topology sequence and real-time collected construction monitoring data, identify the key risk components in the current construction stage and form a set of key risk components;

[0009] S3: For each critical risk component in the critical risk component set, construct a local stress evolution model with the critical risk component as the core, and predict the stress state and stability coefficient of each component in the future preset construction sequence.

[0010] S4: Calculate the risk coupling strength between components based on the predicted stability coefficients of each component and the spatial connectivity in the time-varying structural topology diagram;

[0011] S5: Using the risk coupling strength as the link coefficient, simulate the failure chain effect of each component, and integrate the stability coefficient decay probability of the component to calculate the dynamic instability probability of the bridge.

[0012] S6: Set different warning thresholds for different levels. Based on the relationship between the dynamic instability probability and the warning thresholds for different levels, trigger the corresponding level of bridge instability warning and generate optimized control strategies including construction sequence adjustment, temporary support reinforcement or construction suspension.

[0013] Further, step S1 includes:

[0014] S11: Extract the geometric information, attribute information and initial topological connection relationship of all components from the BIM three-dimensional structural model of bridge construction. The components include permanent components and temporary support components.

[0015] S12: Analyze the construction schedule information, obtain the component construction sequence in units of construction stages, obtain the planned installation completion time and status of each component; and analyze the time pattern of component commissioning during construction to establish the time correlation between structural changes and construction progress.

[0016] S13: Associate the planned installation completion time of the component with the component in the BIM 3D structural model to establish a mapping relationship between the component and the construction phase;

[0017] S14: Based on the component-construction stage mapping relationship, generate a time-varying structural topology diagram for each construction stage. Each time-varying structural topology diagram includes the components that have been planned to be built in the current construction stage and previous construction stages, the effective temporary support components in the current stage, and the connection relationships.

[0018] S15: Based on the component type and the initial topological connection relationship, define and update the spatial connection relationship and mechanical transmission path between components in each time-varying structural topology diagram to form a complete sequence of time-varying structural topology diagrams.

[0019] Further, step S2 includes:

[0020] S21: Extract the time-varying structural topology map corresponding to the current construction stage from the time-varying structural topology map sequence, filter out all completed components that are under stress, and form a set of components to be evaluated;

[0021] S22: For each component in the set of components to be evaluated, collect real-time monitored stress and displacement values, and calculate the historical stress change rate based on historically monitored stress values;

[0022] S23: Based on the spatial connection relationship of each component in the set of components to be evaluated, obtain the displacement value of adjacent components in real time and calculate the deformation compatibility with adjacent components;

[0023] S24: Based on the spatial connection relationship of each component in the time-varying structural topology diagram in the set of components to be evaluated, evaluate the key topological indicators and clarify the core degree and influence weight of the components in the overall bridge structure.

[0024] S25: Set thresholds for stress history rate of change, deformation compatibility, and topological criticality indices for different types of components.

[0025] If the stress history rate of change of a component exceeds the stress history rate of change threshold, the deformation compatibility is lower than the deformation compatibility threshold, or the topological criticality index exceeds the topological criticality index threshold, then the component is determined to be a critical risk component; otherwise, the component is determined to be a non-critical risk component.

[0026] S26: Obtain all critical risk components in the set of components to be evaluated, and then construct the set of critical risk components in the current construction phase.

[0027] Furthermore, the specific methods for evaluating topological key indicators are as follows:

[0028] S241: In the time-varying structural topology diagram corresponding to the current construction stage, count the number of directly connected adjacent components in the set of components to be evaluated, and use this as the topological connectivity of the components.

[0029] S242: Based on the initial topological connection relationship and the mechanical transmission path defined in the time-varying structural topology diagram, determine whether the component is located on the critical force transmission path from the main construction load application point to the foundation support. If so, the judgment value of the critical force transmission path is assigned to 1; otherwise, the judgment value of the critical force transmission path is assigned to 0.

[0030] S243: Assign preset type weight coefficients to permanent components and temporary support components based on their type;

[0031] S244: Based on the topological connectivity, the judgment value of the critical force transmission path, and the type weight coefficient, a weighted calculation is performed to obtain the topological criticality index of the component.

[0032] The formula for calculating the topology criticality index is: Topology criticality index = 0.3 × Topology connectivity + 0.5 × Judgment value of critical force transmission path + 0.2 × Type weight coefficient;

[0033] Further, step S3 includes:

[0034] S31: Based on the time-varying structural topology diagram of the current construction stage, extract the current geometric boundary conditions, mechanical connection status and related component information of key risk components;

[0035] S32: Obtain construction load time sequence distribution data, temporary facility dismantling sequence, and time-varying mechanical parameters of materials related to critical risk components;

[0036] S33: Based on the mechanical connection state and related component information, establish a simplified mechanical model with key risk components as the core, as a local force evolution model. The geometric boundary conditions of the simplified mechanical model are set according to the mechanical transmission path.

[0037] S34: Using the construction load time sequence distribution data, temporary facility dismantling time sequence, and material time-varying mechanical parameters as time-varying input conditions, the parameters of the local stress evolution model are gradually updated according to the future preset construction steps.

[0038] S35: Through iterative calculation, predict the stress state of the component at the end of each future preset construction step, and calculate the stability coefficient of the component under the current construction step based on the predicted stress state and the time-varying mechanical parameters of the material.

[0039] S36: Summarize the stress states predicted by all future preset construction steps, and output the stress state and stability coefficient of the component as it evolves in the sequence of future preset construction steps.

[0040] Furthermore, the method for calculating the stability coefficient under the current construction sequence specifically includes:

[0041] S351: Obtain the allowable stress and elastic modulus of the material of the component under the current construction step; extract the equivalent stress value of the control section of the component under the current construction step from the stress state output by the local stress evolution model;

[0042] S352: Select the appropriate stability coefficient calculation criterion based on the stress type and failure mode of the component; output the stability coefficient of the component.

[0043] Further, step S4 includes:

[0044] S41: Obtain all directly connected component pairs in the current construction phase from the time-varying structural topology diagram;

[0045] S42: For each pair of directly connected components, read the stability coefficient and topological criticality index of each of the two components in the pair, and then realize the basic data fusion of the component's own safety status and the degree of topological coreness.

[0046] S43: Calculate the risk factors of the two components separately, and add the risk factors of the two components together to obtain the risk coupling strength between the component pair; the risk factor is the ratio of the topological criticality index to the stability coefficient of the component.

[0047] Further, step S5 includes:

[0048] S51: Taking the critical risk components in the critical risk component set as the initial failure trigger point, establish a failure propagation network between components based on the spatial connection relationship and mechanical transmission path defined in the time-varying structural topology diagram, and obtain the core starting point and connection path of failure propagation.

[0049] S52: Use the risk coupling strength as the link coefficient of the corresponding connection path in the failure propagation network;

[0050] S53: Starting from each initial failure trigger point, the propagation process of the failure state is recursively simulated based on the connection path and link coefficient of the failure propagation network, and the failure chain effect is dynamically deduced.

[0051] During the dynamic simulation, the critical threshold for instability of the component is set, and the attenuation probability coefficient is calculated based on the risk coupling strength. Then, the attenuation probability of the stability coefficient is calculated based on the stability coefficient, the critical threshold for instability, and the attenuation probability coefficient of the component.

[0052] If the probability of stability coefficient decay is greater than 1, the component is determined to be faulty; otherwise, the component is determined not to be faulty.

[0053] When one of the components is determined to be faulty, the stability coefficient of its adjacent components is reduced proportionally according to the link coefficient of the corresponding connection path.

[0054] Specifically, the formula for calculating the reduced stability coefficient of adjacent components is: Reduced stability coefficient = Original stability coefficient of the structure × (1 - Risk coupling strength / Strength normalization factor);

[0055] S54: Continuously perform dynamic simulation of the failure chain effect of the failure propagation network until no component in the failure propagation network is judged to be failed or the dynamic simulation process has completely covered all components in the time-varying structural topology diagram, and then end the dynamic simulation process.

[0056] S55: In each dynamic simulation, if more than a set number of components are judged to be ineffective or the mechanical transmission path is interrupted, the bridge is judged to be unstable during the dynamic simulation; otherwise, the bridge is judged not to be unstable during the dynamic simulation.

[0057] S56: Calculate the dynamic instability probability of the bridge by the total number of dynamic simulations of the failure chain reaction and the number of times the bridge was determined to be unstable during the dynamic simulation; divide the number of times the bridge was determined to be unstable during the dynamic simulation by the total number of dynamic simulations.

[0058] Furthermore, the formula for the attenuation probability coefficient is: Attenuation probability coefficient = type base value + risk coupling strength × adjustment coefficient;

[0059] The formula for calculating the probability of stability coefficient decay is: Probability of stability coefficient decay = Decay probability coefficient × (Instability critical threshold / stability coefficient).

[0060] A warning system is provided for implementing the above-described BIM-based dynamic early warning method for bridge construction safety risks, comprising:

[0061] Time-varying topology generation module: used to acquire the BIM 3D structural model of the bridge construction and generate a sequence of time-varying structural topology diagrams based on the construction schedule information;

[0062] Risk component identification module: Based on the time-varying structural topology sequence and real-time collected construction monitoring data, it identifies key risk components in the current construction stage and forms a set of key risk components;

[0063] Stress evolution prediction module: Used to construct a local stress evolution model with the key risk component as the core for each key risk component in the key risk component set, and predict the stress state and stability coefficient of each component in the future preset construction sequence;

[0064] Coupling strength calculation module: used to calculate the risk coupling strength between components based on the predicted stability coefficients of each component and the spatial connection relationship in the time-varying structural topology diagram;

[0065] Instability probability calculation module: Used to simulate the failure chain effect of each component with the risk coupling strength as the link coefficient, and integrate the stability coefficient decay probability of the component to calculate the dynamic instability probability of the bridge.

[0066] Early warning strategy generation module: used to set early warning thresholds of different levels, and trigger bridge instability early warnings of the corresponding level based on the magnitude between the dynamic instability probability and the early warning thresholds of different levels, and generate optimized control strategies including construction sequence adjustment, temporary support reinforcement or construction suspension.

[0067] The beneficial effects of this invention are as follows:

[0068] This invention proposes a BIM-based dynamic early warning method and system for bridge construction safety risks. By generating time-varying structural topology maps step by step, identifying key risk component sets, constructing local stress evolution models, calculating the risk coupling strength between components, simulating failure chain effects and calculating dynamic instability probability, triggering graded early warnings and generating optimized control strategies, dynamic prediction and precise control of safety risks throughout the entire bridge construction process are achieved.

[0069] This invention solves the problems of traditional bridge construction safety management, which relies on static assessment, has delayed early warning, lacks prediction of risk correlation and evolution trend, and has insufficient targeted control. It avoids control omissions and waste of efficiency caused by fixed early warning thresholds, improves the timeliness and accuracy of bridge construction safety risk early warning and the operability of control measures, and provides reliable technical support for bridge construction safety. Attached Figure Description

[0070] Figure 1 This is a flowchart of a BIM-based dynamic early warning method for bridge construction safety risks.

[0071] Figure 2 This is a schematic diagram of a BIM-based dynamic early warning system for bridge construction safety risks. Detailed Implementation

[0072] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0073] like Figure 1 As shown, a BIM-based dynamic early warning method for bridge construction safety risks is characterized by the following steps:

[0074] S1: Obtain the BIM 3D structural model of the bridge construction and generate a time-varying structural topology sequence based on the construction schedule information, reflecting the dynamic changes of completed components, temporary support components and connection relationships in each construction stage.

[0075] In this embodiment, in the scenario where the structural composition and stress state of the bridge construction are constantly changing at each stage of construction, in order to avoid the risk assessment being out of touch with the actual working conditions due to the use of a fixed structural model, it is necessary to generate a time-varying structural topology map based on the bridge's BIM three-dimensional structural model and construction schedule information, so as to build a dynamic structural analysis carrier that adapts to the entire construction process and provide a structural data foundation for subsequent safety risk identification and early warning.

[0076] Step S1 specifically includes:

[0077] S11: Extract the geometric information, attribute information and initial topological connection relationship of all components from the BIM three-dimensional structural model of bridge construction;

[0078] The components include permanent components and temporary support components to ensure that the collected basic data can fully cover all types of components involved in the construction.

[0079] In this embodiment, during the extraction of geometric information, attribute information, and initial topological connection relationships of components, it is necessary to ensure that the geometric information of the components covers data such as dimensions, spatial location, and cross-sectional shape; the attribute information covers key parameters such as material type, design strength, and service life; and the initial topological connection relationships cover connection methods such as welding, bolting, and support between components. For example, for beam components, it is necessary to extract geometric information such as beam length, beam height, and cross-sectional area; attribute information such as concrete strength grade and elastic modulus; and topological connection relationships such as the connection node types between the beam and piers and temporary supports, to ensure that the extracted basic data can completely reflect the initial state of the bridge structure.

[0080] S12: Analyze the construction schedule information, obtain the component construction sequence in units of construction stages, obtain the planned installation completion time and status of each component; and analyze the time pattern of component commissioning during construction to establish the time correlation between structural changes and construction progress.

[0081] In this embodiment, the construction phases can be divided into pile foundation construction, cap construction, pier construction, and beam erection, each corresponding to different component installation tasks. During the analysis process, the time nodes in the construction schedule need to be scientifically matched with the specific components. For example, the planned completion time for the installation of a certain span of beam is defined as the end of a certain construction phase, with the status being completed and put into load-bearing capacity. Similarly, the planned completion time for the installation of a certain temporary support is defined as the preparation phase before beam erection, with the status being installed in place and possessing support capacity. This ensures that the obtained construction sequence accurately reflects the rhythm of component deployment during the construction process.

[0082] S13: Associate the planned installation completion time of the component with the component in the BIM 3D structural model to establish a mapping relationship between the component and the construction stage, and realize the integration of component spatial information and construction time information;

[0083] In this embodiment, the association process requires using the construction stage as a timeline to map the completion time of each component's installation to the corresponding construction stage, forming a one-to-one mapping relationship between components and construction stages. For example, pile foundation components are mapped to the pile foundation construction stage, pile cap components to the pile cap construction stage, and temporary supports and beam components to the beam erection stage. Through this mapping relationship, the scope of completed components corresponding to each construction stage can be clearly defined, providing a clear selection basis for the subsequent generation of time-varying structural topology diagrams.

[0084] S14: Based on the mapping relationship between components and construction stages, generate a time-varying structural topology diagram for each construction stage. Each time-varying structural topology diagram includes the components that have been planned to be built in the current construction stage and previous construction stages, the effective temporary support components in the current stage, and the connection relationships; restore the actual structural composition of each construction stage through the time-varying structural topology diagram.

[0085] In the process of generating the time-varying structural topology diagram in this embodiment, it is necessary to strictly follow the time sequence of construction stages, selecting components that have been planned to be built in the current construction stage and previous construction stages, and simultaneously selecting effective temporary support components in the current construction stage, while removing components that have not been installed and those that have failed. For example, in the time-varying structural topology diagram of the beam erection stage, it must include permanent components such as completed pile foundations, pile caps, and piers, as well as temporary supports used to support the beam in the current construction stage, while removing subsequent spans of beams that have not yet been erected and previously dismantled temporary facilities, to ensure that each time-varying structural topology diagram can reproduce the actual structural composition of the corresponding construction stage.

[0086] S15: Based on the component type and the initial topological connection relationship, define and update the spatial connection relationship and mechanical transmission path between components in each time-varying structural topology diagram to form a complete sequence of time-varying structural topology diagrams.

[0087] This embodiment provides dynamic structural foundation data for subsequent work such as identifying key risk components and predicting local stress evolution based on real-time monitoring data through a time-varying structural topology sequence. In defining and updating the spatial connection relationships and mechanical transfer paths between components, it is necessary to consider the differences in component types and connection methods to clarify the load transfer direction and path between components. For example, for rigid connections between permanent components, a continuous mechanical transfer path needs to be defined, allowing loads to be directly transferred to adjacent components through the connection nodes. Furthermore, for flexible connections between permanent components and temporary support components, a mechanical transfer path with constraints needs to be defined, and the deformation characteristics of the connection nodes must be considered during the load transfer process.

[0088] By updating the mechanical transmission path of each time-varying structural topology map, the resulting sequence of time-varying structural topology maps can fully present the dynamic evolution of structural composition and mechanical transmission characteristics throughout the entire bridge construction process, providing dynamic structural analysis data for subsequent dynamic early warning of construction safety risks.

[0089] S2: Based on the time-varying structural topology sequence and real-time collected construction monitoring data, key risk components in the current construction stage are identified and a set of key risk components is formed.

[0090] In this embodiment, to avoid the inefficiency of risk identification caused by indiscriminate analysis of all components, and to identify high-risk components in the current construction stage, it is necessary to combine the time-varying structural topology sequence with real-time collected construction monitoring data to identify key risk components, so as to improve the pertinence and timeliness of risk assessment.

[0091] Step S2 specifically includes:

[0092] S21: Extract the time-varying structural topology map corresponding to the current construction stage from the time-varying structural topology map sequence, screen out all completed components that are under stress, and form a set of components to be evaluated; accurately delineate the risk assessment scope under the current construction stage conditions through the components in the set of components to be evaluated;

[0093] In this embodiment, during the screening of completed and stressed components, it is necessary to eliminate components that have not yet been installed and temporary support components that have been dismantled or not yet put into load-bearing capacity, based on the structural composition and stress state of the components in the current construction stage as presented by the time-varying structural topology diagram. For example, beam components in the prefabrication stage and construction scaffolding that has completed its function are eliminated to ensure that the set of components to be evaluated fully matches the actual stress structure under the current construction stage conditions.

[0094] S22: For each component in the set of components to be evaluated, collect real-time monitored stress and displacement values, and calculate the historical stress change rate based on historically monitored stress values;

[0095] In this embodiment, the formula for calculating the historical stress variation rate is: Historical Stress Variation Rate = (Recent Average Stress Growth Average) / (Historical Average Stress Level). The recent average stress growth average is calculated based on the average stress values ​​detected over a continuous monitoring period. The historical average stress level is selected as the average stress values ​​monitored during the stable operation period after the component was put into service. For example, the average stress value growth monitored over the past 72 hours for a certain bridge pier component is selected as the recent average stress growth average, and the average stress value monitored within 30 days after the bridge pier was put into service is selected as the historical average stress level. The historical stress variation rate is calculated by the ratio of the average stress growth average to the historical average stress level, which can intuitively reflect the recent trend of the component's stress state and thus capture the risk signal of abnormal stress growth.

[0096] S23: Based on the spatial connection relationship of each component in the set of components to be evaluated, obtain the displacement value of adjacent components in real time and calculate the deformation coordination degree with adjacent components; the deformation coordination degree can be used to determine whether the deformation between components is coordinated and whether there is a risk of local imbalance.

[0097] This embodiment quantifies the deformation coordination between components by measuring the deformation compatibility with adjacent components, thus promptly identifying potential local deformation imbalances. The formula for calculating the deformation compatibility is: Deformation Compatibility = 1 - (Modulus of displacement difference with adjacent components / Allowable deformation). Here, the allowable deformation is a pre-set threshold based on design specifications, component type, and connection characteristics. For example, for the connection between a reinforced concrete beam and a pier, the allowable deformation can be set at 2 mm, referencing the "Design Specifications for Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts." The formula for calculating deformation compatibility quantifies the deformation coordination between components and adjacent components. A lower allowable deformation indicates a greater difference in deformation between components, and a higher risk of local stress imbalance.

[0098] S24: Based on the spatial connection relationship of each component in the time-varying structural topology diagram in the set of components to be evaluated, evaluate the key topological indicators and clarify the core degree and influence weight of the components in the overall bridge structure.

[0099] By using coreity and influence weighting, critical components that significantly impact bridge structural stability can be accurately identified. The specific method for evaluating topological criticality indicators is as follows:

[0100] S241: In the time-varying structural topology diagram corresponding to the current construction stage, count the number of directly connected adjacent components in the set of components to be evaluated, and use this as the topological connectivity of the components.

[0101] Time-varying structural topology diagrams reflect the actual structural composition and spatial connection status of components at the current construction stage. By statistically analyzing the number of directly connected adjacent components, the tightness of component connections within the current structural network can be accurately reflected. For example, if a pier cap component directly connects to four piles and two piers in the current time-varying structural topology diagram, its topological connectivity is 6; a temporary support component directly connects to only one beam segment, resulting in a topological connectivity of 1. Through the statistical analysis of topological connectivity, the influence range of a component within the structure can be preliminarily determined. The greater the number of adjacent component connections, the wider the impact of its state changes on surrounding components.

[0102] S242: Based on the initial topological connection relationship and the mechanical transmission path defined in the time-varying structural topology diagram, determine whether the component is located on the critical force transmission path from the main construction load application point to the foundation support. If so, the judgment value of the critical force transmission path is assigned to 1; otherwise, the judgment value of the critical force transmission path is assigned to 0.

[0103] The initial topological connections provide the inherent connection basis between components, while the mechanical transmission paths in the time-varying structural topology diagram clarify the direction and path of load transmission in the current construction stage. The judgment process requires tracing the points of application of the main construction loads and analyzing the critical force transmission paths from the loads to the foundation supports. If a component is on a critical force transmission path, the judgment value for the critical force transmission path is 1; otherwise, it is 0. For example, during the beam erection stage, the points of application of the main construction loads are the contact points between the beam and the temporary support structure. The loads need to be transmitted to the foundation through temporary supports, piers, pile caps, and pile foundations. Piers and pile cap components on this transmission path all have a critical force transmission path judgment value of 1. The purpose of this step is to identify the components that play a decisive role in load transmission; if such components are at risk, it can easily lead to an imbalance in the overall load-bearing system.

[0104] S243: Assign preset type weight coefficients to permanent components and temporary support components based on their type;

[0105] Different types of structural components have fundamentally different impacts on bridge construction safety and long-term operation. Permanent components, as the core components of the bridge's main structure, directly determine the bridge's long-term load-bearing capacity and stability, and therefore require higher weighting. Conversely, temporary support components only play a role in specific construction phases, with limited scope and duration of influence, and their weighting can be appropriately reduced. For example, setting the type weighting coefficient for permanent components to 1.0 and the type weighting coefficient for temporary support components to 0.8, based on structural safety impact sensitivity analysis, can match the safety impact priority of different component types.

[0106] S244: Based on the topological connectivity, the judgment value of the critical force transmission path, and the type weight coefficient, a weighted calculation is performed to obtain the topological criticality index of the component.

[0107] In this embodiment, the calculation formula for the topology criticality index is: Topology criticality index = 0.3 × Topology connectivity + 0.5 × Judgment value of critical force transmission path + 0.2 × Type weight coefficient; where the weight allocation is determined based on the structural safety impact sensitivity analysis, the highest weight of 0.5 is assigned to the judgment result of the critical force transmission path to highlight the importance of the core force transmission component; the second is the topology connectivity, with a weight of 0.3 to reflect the influence radiation range of the component; in addition, the type weight coefficient is assigned a weight of 0.2 to distinguish the essential differences between component types. For example, if the topology connectivity of a permanent component is 5 and it is located on a critical force transmission path (judgment value of critical force transmission path = 1), then the corresponding topology criticality index = 0.3 × 5 + 0.5 × 1 + 0.2 × 1.0 = 2.2; if the topology connectivity of a temporary support component is 2 and it is not located on a critical force transmission path (judgment value of critical force transmission path = 0), then the corresponding topology criticality index = 0.3 × 2 + 0.5 × 0 + 0.2 × 0.8 = 0.76.

[0108] The topological criticality index obtained by the above weighted calculation method can comprehensively integrate the connection characteristics, force transmission role and type attributes of the component to quantify the topological criticality of the component, thereby avoiding the one-sidedness caused by single-dimensional evaluation.

[0109] S25: Set thresholds for stress history rate of change, deformation compatibility, and topological criticality indices for different types of components.

[0110] If the stress history rate of change of a component exceeds the stress history rate of change threshold, the deformation compatibility is lower than the deformation compatibility threshold, or the topological criticality index exceeds the topological criticality index threshold, then the component is determined to be a critical risk component; otherwise, the component is determined to be a non-critical risk component.

[0111] S26: Obtain all critical risk components in the set of components to be evaluated, and then construct the set of critical risk components in the current construction phase.

[0112] The key risk component set forms a set of components that focus on core risk points, providing a basis for subsequent targeted risk analysis and the formulation of control measures.

[0113] Different types of components have different material properties and stress forms, and the corresponding threshold standards need to be set differently to ensure the scientific nature of the judgment results. Specifically, the threshold for the rate of change of stress history should be set with reference to the allowable stress variation range of the component material; the threshold for deformation compatibility should be set with reference to the allowable deformation difference between components in the design code; and the threshold for topological criticality indicators should be set in combination with the structural safety level requirements of the current construction stage. Through the synergistic constraints of multi-dimensional thresholds, a comprehensive judgment of the risk status of components can be achieved.

[0114] For example, for reinforced concrete piers, the threshold for the historical rate of change of stress is set to 0.08, the threshold for deformation compatibility is set to 0.7, and the threshold for topological criticality is set to 0.6; for steel temporary support members, the threshold for the historical rate of change of stress is set to 0.15, the threshold for deformation compatibility is set to 0.65, and the threshold for topological criticality is set to 0.5. If a member meets any of the above conditions and its corresponding threshold exceeds the threshold, it can be determined that the member has a potential safety risk. Members that meet any threshold condition are added to the set of critical risk members in the current construction phase, providing accurate targeted information for subsequent risk management.

[0115] S3: For each critical risk component in the critical risk component set, construct a local stress evolution model with the critical risk component as the core, and predict the stress state and stability coefficient of each component in the future preset construction sequence.

[0116] In this embodiment, in order to understand the evolution of the mechanical state of key risk components in subsequent construction, it is necessary to construct a dedicated local stress evolution model for each key risk component in the key risk component concentration, so as to accurately predict the stress state and stability coefficient of each key risk component in the future preset construction sequence, and provide scientific data support for the early deployment of subsequent dynamic safety early warning and targeted control measures.

[0117] Step S3 specifically includes:

[0118] S31: Based on the time-varying structural topology diagram of the current construction stage, extract the current geometric boundary conditions, mechanical connection status and related component information of key risk components;

[0119] Geometric boundary conditions are the core geometric parameters of critical risk components, including cross-sectional dimensions, spatial orientation, and constraint types. Furthermore, the mechanical connection status requires clarifying the connection form between the critical risk component and adjacent components, such as welding, bolting, rigid connection, hinged connection, etc., as well as the mechanical transmission characteristics of the connection nodes. Simultaneously, the associated component information filters out permanent and temporary support components that have a direct mechanical transmission relationship with the critical risk component, excluding auxiliary components without mechanical connections. For example, if the critical risk component is a mid-span main beam segment of a continuous beam bridge, its geometric parameters such as cross-sectional height (1.8m), width (12m), and web thickness (0.3m) are extracted from the time-varying structural topology diagram. The rigid connection status of its wet joints with adjacent main beam segments and the elastic support characteristics with temporary supports are clarified, and the associated components are identified as adjacent main beam segments, temporary supports, and corresponding supporting piers.

[0120] S32: Obtain construction load time sequence distribution data, temporary facility dismantling sequence, and time-varying mechanical parameters of materials related to critical risk components;

[0121] In this embodiment, the construction load time sequence distribution data needs to be analyzed in conjunction with the specific content of subsequent preset construction steps to determine the various loads acting on key risk components and their time-varying patterns, including construction machinery loads, material stacking loads, prestressing tension loads, and secondary dead loads. For example, if the third construction step for a key risk component will involve prestressing tensioning, the application time, tension value, and location of the tension load need to be clearly defined. If the fifth construction step involves hoisting the bridge deck pavement layer, the stacking time of the pavement material, load distribution density, and time sequence changes need to be clearly defined.

[0122] In this embodiment, the dismantling sequence of temporary facilities is extracted from the construction schedule information to clarify the dismantling time nodes of temporary supports, scaffolding, and other facilities related to the stress on critical risk components. For example, if a temporary support is planned to be dismantled at the end of the fourth construction step, this time node needs to be entered into the data system.

[0123] In this embodiment, the time-varying mechanical parameters of the material reflect the changing patterns of mechanical indicators such as material strength and elastic modulus over time. For example, the strength of concrete components gradually increases with the extension of curing time, and the elastic modulus of steel fluctuates with changes in ambient temperature. The corresponding time-varying parameter curves need to be obtained in combination with the material type and construction environment conditions.

[0124] S33: Based on the mechanical connection state and related component information, establish a simplified mechanical model with key risk components as the core, as a local force evolution model. The geometric boundary conditions of the simplified mechanical model are set according to the mechanical transmission path.

[0125] In this embodiment, the construction of the simplified mechanical model must adhere to the principles of preserving core mechanical properties and reasonably eliminating secondary interference factors. While ensuring computational accuracy, the model complexity is simplified to improve computational efficiency. Specifically, the geometric boundary conditions of the simplified mechanical model must be strictly set according to the mechanical transmission paths defined in the time-varying structural topology diagram to ensure that the mechanical transmission logic of the model is consistent with the actual structure. For example, beam segments primarily subjected to bending are simplified to Euler-Bernoulli beam models, and columns primarily subjected to compression are simplified to Euler compression bar models.

[0126] For example, the time-varying topology of the upper chord (a critical risk component) of a cantilevered assembly section of a steel truss bridge shows that it is a member with bolted connections at both ends via gusset plates and a temporary hanger in the middle. When constructing a simplified mechanical model, a two-force member element subjected only to axial force is selected as the model type, and based on the bending resistance characteristics of bolted connections, the two ends of the member are simplified to hinged connections. Simultaneously, regarding loads, the member's self-weight, node-transferred loads, and the unloading effect of the temporary hanger are equivalent to axial pressure acting on both ends of the member.

[0127] Furthermore, the geometric boundary conditions of the simplified mechanical model must be strictly set according to the mechanical transmission path defined in the time-varying structural topology diagram to ensure that the mechanical transmission logic of the model is consistent with the actual structure. For example, for a pier component that is rigidly connected to the abutment at the bottom and hinged to the beam at the top, based on the force transmission path of "beam-pier-abutment", the bottom is set as a fixed end constraint and the top is set as a hinged support constraint in the simplified mechanical model. The nodal loads transmitted by the beam and the elastic constraints of the temporary supports are taken into account, while non-load-bearing parts such as the pier decorative layer are ignored.

[0128] S34: Using the construction load time sequence distribution data, temporary facility dismantling time sequence, and material time-varying mechanical parameters as time-varying input conditions, the parameters of the local stress evolution model are gradually updated according to the future preset construction steps.

[0129] In this embodiment, the future pre-set construction steps need to be scientifically divided in conjunction with the construction schedule to clarify the time span, construction content, and key time nodes of each construction step. For example, the subsequent construction process is divided into 6 pre-set construction steps, each with a duration of 7 days, covering key operations such as prestressing tensioning, temporary support adjustment, and second-phase permanent load hoisting.

[0130] During the parameter update process of the local stress evolution model, the chronological order of the construction steps must be strictly followed. Construction load data for each corresponding construction step should be entered into the local stress evolution model sequentially. The support constraint conditions of the local stress evolution model should be updated at the corresponding construction step nodes according to the dismantling sequence of temporary facilities. Simultaneously, the material mechanical parameters in the local stress evolution model should be updated synchronously based on the time-varying material mechanical parameter curves. For example, in the subsequent third construction step, the chronological data of the prestressed tension load should be input into the local stress evolution model; at the end of the fourth construction step, the elastic support constraint parameters corresponding to the temporary supports should be deleted; throughout the entire iterative calculation process, the strength and elastic modulus parameters of the concrete components should be updated synchronously according to the curing time.

[0131] S35: Through iterative calculation, predict the stress state of the component at the end of each future preset construction step, and calculate the stability coefficient of the component under the current construction step based on the predicted stress state and the time-varying mechanical parameters of the material.

[0132] The specific methods for calculating the stability coefficient under the current construction sequence include:

[0133] S351: Obtain the allowable stress and elastic modulus of the material of the component under the current construction step; extract the equivalent stress value of the control section of the component under the current construction step from the stress state output by the local stress evolution model;

[0134] In this embodiment, the allowable stress of the component material under the current construction step is a safety threshold determined based on the material type, stress form, and relevant design specifications. It directly determines the upper limit of the component's load-bearing safety and needs to be selected in conjunction with the component's working state corresponding to the current construction step. In addition, the elastic modulus of the material is a parameter for calculating the mechanical response of the component and will change dynamically with the material age and environmental conditions. The specific value corresponding to the current construction step needs to be extracted from the time-varying mechanical parameters of the material. For example, if the component is a steel beam made of Q355 steel and is subjected to axial compressive load under the current construction step, its allowable stress is 210MPa according to the steel structure design specifications. If the component is a C50 concrete pier and the current construction step is 7 days after pouring, the elastic modulus at this time extracted from the time-varying mechanical parameter curve is 3.2×104MPa.

[0135] In this embodiment, the control section is the most unfavorable section of the component under the current stress system. Its stress state directly determines the overall safety performance of the component. It typically includes the mid-span section, the section near the support, the root section, and the turning section. Simultaneously, the stress state output by the local stress evolution model includes multi-dimensional data such as normal stress, shear stress, and principal stress across the entire component section. These different types of stress need to be converted into a unified equivalent stress value for the control section to ensure the comparability of stress indicators and the objectivity of the assessment. For example, the control section of the main beam component of a continuous beam bridge is the mid-span section. The local stress evolution model outputs a normal stress of 12 MPa and a shear stress of 3 MPa for this section. The equivalent stress value of the control section calculated using the fourth strength theory is 12.37 MPa. The control section of a bridge pier component is the bottom root section. The local stress evolution model outputs a compressive stress of 160 MPa and a shear stress of 15 MPa for this section. The calculated equivalent stress value of the control section is 160.7 MPa.

[0136] S352: Select an appropriate stability coefficient calculation criterion based on the stress type and failure mode of the component; output the stability coefficient of the component as a quantitative indicator to evaluate the safety reserve of the component under the current construction sequence.

[0137] In this embodiment, the failure modes of components under different stress types differ fundamentally, and the calculation of the stability coefficient needs to be specifically adapted to ensure the validity of the calculation results. Specifically, if a component mainly bears bending, tensile, or shear loads, the failure mode is characterized by failure due to the depletion of material strength, which indicates that the component is primarily controlled by strength. If a component mainly bears axial compressive loads, the failure mode is characterized by failure due to overall instability, which indicates that the component is primarily controlled by stability.

[0138] For components primarily controlled by strength, the stability coefficient is the ratio of the allowable stress of the material to the equivalent stress of the control section. This ratio directly reflects the component's strength safety reserve. The larger the ratio, the more sufficient the strength redundancy of the component and the lower the safety risk; the closer the ratio is to 1, the closer the component is to its strength limit and the extremely high safety risk. For example, if a reinforced concrete beam is a strength-controlled component, and the allowable stress of the material at the current construction stage is 15 MPa, and the equivalent stress of the control section is 10 MPa, then the stability coefficient = 15 / 10 = 1.5, indicating that the component currently has sufficient strength safety reserve. If another beam has an equivalent stress of 14.5 MPa at the control section and an allowable stress of 15 MPa, then the stability coefficient = 15 / 14.5 ≈ 1.03, indicating that the component's strength safety reserve is extremely low, and immediate control measures are required.

[0139] For components where stability control is the primary concern, the stability coefficient is the ratio of the component's critical buckling stress to the actual compressive stress it bears. The critical buckling stress is the stress value corresponding to the critical pressure at which the component will fail. Its calculation requires integrating the material's elastic modulus and the component's geometric features in the current step. The component's geometric features are extracted from the BIM 3D structural model, including cross-sectional dimensions, cross-sectional shape, and calculated length. These parameters determine the component's resistance to instability. For example, a certain steel temporary support is a stability-controlled component. Under the current construction sequence, the material's elastic modulus is 2.06 × 10⁵ MPa, the cross-section is circular with a diameter of 300 mm, and the calculated length is 6 m. The buckling critical stress calculated using Euler's formula is 245 MPa, and the actual compressive stress borne by the component is 120 MPa. Therefore, the stability coefficient = 245 / 120 ≈ 2.04, indicating that the component has sufficient safety reserves against instability. If another temporary support actually bears a compressive stress of 230 MPa and has a buckling critical stress of 245 MPa, then the stability coefficient = 245 / 230 ≈ 1.07, indicating that the component is close to the critical state of instability and has an extremely high safety risk.

[0140] Based on this, the criteria for calculating the stability coefficient include:

[0141] For components where strength control is the primary factor, the stability coefficient is the ratio of the allowable stress of the material to the equivalent stress of the control section.

[0142] For components where stability control is the primary concern, the stability coefficient is the ratio of the critical buckling stress to the actual compressive stress. The calculation of the critical buckling stress needs to take into account the material's elastic modulus and the component's geometric characteristics under the current construction sequence.

[0143] S36: Summarize the stress states predicted by all future preset construction steps, and output the stress state and stability coefficient of the component as it evolves in the sequence of future preset construction steps.

[0144] By outputting the evolution data of stress state and stability coefficient of components in the future preset construction sequence, the changing law of component mechanical state with the construction process can be clearly presented.

[0145] Following the chronological order of the planned construction steps, the equivalent stress values ​​and stability coefficients of the control sections corresponding to each construction step are compiled and summarized. Key construction information for each step is also linked and recorded to ensure data consistency and traceability. For example, if six construction steps are planned, the equivalent stress values ​​and stability coefficients of the main beam mid-span sections from step 1 to step 6 need to be summarized sequentially, and key milestones such as prestressing tensioning in step 2 and temporary support removal in step 4 need to be marked.

[0146] Simultaneously, data consistency verification is required during the aggregation process to ensure that the parameter definitions and calculation standards for all construction steps are consistent. If any abnormal data is found for a particular construction step, it needs to be backtracked, corrected, and re-included in the aggregation. Finally, the aggregated data is transformed into intuitive forms such as evolution curves and output in a standardized format to meet the input requirements of the subsequent risk warning system, providing data support for risk trend prediction and control decisions.

[0147] S4: Calculate the risk coupling strength between components based on the predicted stability coefficients of each component and the spatial connectivity in the time-varying structural topology diagram;

[0148] In this embodiment, in order to avoid the control oversight caused by the isolated assessment of the risk of a single component, it is necessary to calculate the risk coupling strength by combining the stability coefficient and the spatial connection relationship in the time-varying structural topology diagram, so as to accurately control the overall risk situation of the structure.

[0149] Step S4 specifically includes:

[0150] S41: Obtain all directly connected component pairs in the current construction stage from the time-varying structural topology diagram to ensure that the obtained component pairs can truly reflect the direct mechanical relationship between components in the current construction state;

[0151] For example, from the time-varying structural topology diagram of the current construction stage of a continuous beam bridge, all directly connected component pairs such as the main beam and pier, the main beam and temporary support, and the pier and abutment can be obtained to cover the core mechanical transmission nodes in the current structure.

[0152] S42: For each pair of directly connected components, read the stability coefficient and topological criticality index of each of the two components in the pair, and then realize the basic data fusion of the component's own safety status and the degree of topological coreness.

[0153] For example, for the main beam and pier as a component pair, the stability coefficient and topological criticality index of the main beam and the corresponding stability coefficient and topological criticality index of the pier are read separately to ensure that the data extraction and the correspondence between the component pair are accurate.

[0154] S43: Calculate the risk factors of the two components separately, and add the risk factors of the two components together to obtain the risk coupling strength between the component pair; the risk factor is the ratio of the topological criticality index to the stability coefficient of the component.

[0155] Risk factors can effectively integrate the topological importance of a component with its own safety reserve level, quantifying the risk transmission potential of a single component to adjacent components. Components with higher topological criticality and lower safety reserves have larger risk factors, and their potential to transmit risk to adjacent components is also stronger. For example, a main beam component has a topological criticality index of 0.8 and a predicted stability coefficient of 1.5, and its calculated risk factor is 0.8 / 1.5≈0.53. The risk factor can effectively distinguish the difference in risk transmission potential between two components.

[0156] Risk coupling strength quantifies the degree of risk interaction between components, providing a basis for determining the priority of risk transmission. A higher risk coupling strength value indicates a greater likelihood and impact of risk transmission between the two components, making them more likely to be prioritized for control. For example, the sum of the risk factors for the main beam and pier pair mentioned above yields a risk coupling strength of 0.53 + 0.5 = 1.03; however, if the risk factors for another pair of main beams and temporary support components are 0.7 and 0.6 respectively, the risk coupling strength is 1.3, indicating a higher degree of risk coupling in the latter pair, requiring priority for targeted control.

[0157] S5: Using the risk coupling strength as the link coefficient, simulate the failure chain effect of each component, and integrate the stability coefficient decay probability of the component to calculate the dynamic instability probability of the bridge.

[0158] In this embodiment, in order to predict the overall instability risk of the bridge and avoid ignoring the potential failure by only assessing the safety status of a single component in isolation, it is necessary to simulate the chain effect of failure by using the risk coupling strength as the link coefficient and calculate the dynamic instability probability by integrating the stability coefficient decay probability, so as to fully grasp the dynamic safety situation during the bridge construction process.

[0159] Step S5 specifically includes:

[0160] S51: Taking the critical risk components in the critical risk component set as the initial failure trigger point, establish a failure propagation network between components based on the spatial connection relationship and mechanical transmission path defined in the time-varying structural topology diagram, and obtain the core starting point and connection path of failure propagation.

[0161] The critical risk components, which are themselves weak links in structural safety, can be used as trigger points to focus on high-risk sources. For example, from the critical risk components of a continuous beam bridge in the current construction stage, main beam segments and temporary supports can be selected as initial trigger points. Based on the connection relationships between the main beam and piers, the main beam and temporary supports, and the temporary supports and abutments in the time-varying structural topology diagram, a network containing all potential failure propagation paths can be constructed.

[0162] S52: Using the risk coupling strength as the link coefficient of the corresponding connection path in the failure propagation network, so that the link coefficient can accurately characterize the possibility of failure propagating along the corresponding connection path, and ensure the quantification of the failure propagation direction and probability.

[0163] Risk coupling strength has pre-quantified the degree of mutual influence of risks between components. Using it as a link coefficient can directly characterize the probability of failure propagating along the corresponding path. The larger the link coefficient, the easier it is for the failure to spread through that path, thus making the simulation of failure propagation more quantitative and improving the accuracy of dynamic extrapolation of failure chain effects. For example, if the risk coupling strength between the main beam and the temporary support is higher than that between the main beam and the pier, then the link coefficient of the corresponding connection path is larger for the former, and the probability of failure propagating from the main beam to the temporary support is also higher during dynamic extrapolation.

[0164] S53: Starting from each initial failure trigger point, the propagation process of the failure state is recursively simulated based on the connection path and link coefficient of the failure propagation network, and the failure chain effect is dynamically deduced.

[0165] During the dynamic simulation, the critical threshold for instability of the component is set, and the attenuation probability coefficient is calculated based on the risk coupling strength. Then, the attenuation probability of the stability coefficient is calculated based on the stability coefficient, the critical threshold for instability, and the attenuation probability coefficient of the component.

[0166] In this embodiment, instability critical thresholds are defined for critical risk components within a critical risk component cluster and for adjacent components affected by failure propagation. These instability critical thresholds are preset based on design specifications and engineering experience, and the thresholds differ for different types of components. For example, the instability critical threshold is set to 1.5 for permanent components and 1.2 for temporary support components. This differentiated setting meets the safety level requirements of different components, making the determination of component failure more targeted and reasonable.

[0167] In this embodiment, based on the risk coupling strength and component type between components, a corresponding attenuation probability coefficient is determined for each component connection relationship. Specifically, the formula for the attenuation probability coefficient is: Attenuation probability coefficient = Type base value + Risk coupling strength × Adjustment coefficient; where, if both ends of the connection relationship are permanent components, the type base value is 0.5; if at least one end of the connection relationship is a temporary support component, the type base value is 0.8, and the adjustment coefficient is uniformly preset to 0.1.

[0168] The above calculation method integrates the influence of component connection type and risk coupling strength, enabling the attenuation probability coefficient to accurately characterize the probability level of component stability coefficient attenuation caused by failure propagation under different connection relationships. For example, the connection between permanent components and temporary support components has a higher type base value, and its attenuation probability coefficient is usually greater than that between two permanent components, which is consistent with the engineering reality that temporary support components have relatively weak stability and are easily affected by failure propagation.

[0169] For the dynamic simulation of each failure cascade effect, a key risk component is randomly selected from the set of key risk components as the initial failure component. Specifically, the random selection method can cover scenarios where different key risk components serve as failure sources, thus avoiding the one-sidedness of dynamic simulation results caused by a fixed initial trigger point and improving the comprehensiveness of subsequent probability calculations. At the same time, recursive simulation calculations are performed according to the connection path of the failure propagation network. When the simulation calculation reaches a component, the stability coefficient decay probability of the current component is calculated based on the stability coefficient, instability critical threshold, and decay probability coefficient of the current component.

[0170] Specifically, the formula for calculating the stability coefficient decay probability is: Stability coefficient decay probability = Decay probability coefficient × (Instability critical threshold / Stability coefficient); if the calculated stability coefficient decay probability is greater than 1, the component is judged to have failed. This calculation combines the component's own safety state, instability judgment criteria, and the decay characteristics of the propagation path, making the failure judgment more scientific and quantitatively based. For example, in the dynamic simulation of a bridge pier component, by combining its current stability coefficient, the preset instability critical threshold, and the corresponding decay probability coefficient, the calculated stability coefficient decay probability is 1.2; if it is greater than 1, the bridge pier is judged to have failed.

[0171] If the probability of stability coefficient decay is greater than 1, the component is determined to be faulty; otherwise, the component is determined not to be faulty.

[0172] When one of the components is determined to be faulty, the stability coefficient of its adjacent components is reduced proportionally according to the link coefficient of the corresponding connection path, so as to truly restore the impact of failure propagation on the safety status of adjacent components.

[0173] In this embodiment, the recursive simulation method can track the failure propagation trajectory step by step to fully recreate the dynamic process of the failure spreading from the initial trigger point to surrounding components, avoiding omission of key propagation nodes. Specifically, when a component is determined to have failed during the dynamic simulation, the stability coefficient of the corresponding adjacent components will be proportionally reduced based on the risk coupling strength of the connection path.

[0174] Specifically, the formula for reducing the stability coefficient of adjacent components is: Reduced stability coefficient = Original stability coefficient × (1 - Risk coupling strength / Strength normalization factor). The strength normalization factor is obtained by comparing the maximum risk coupling strength of all directly connected component pairs in the current construction phase with 1. If the maximum risk coupling strength is greater than or equal to 1, the strength normalization factor is the maximum risk coupling strength; otherwise, it is 1. Setting the strength normalization factor ensures that the reduction ratio of the stability coefficient is always between 0 and 1, avoiding the unreasonable situation of a negative stability coefficient. For example, after a temporary support fails, the adjacent main beam component calculates the reduction ratio based on the risk coupling strength between them and the normalization factor, and accordingly reduces its own stability coefficient, accurately reflecting the decrease in the safety status of the main beam due to the failure of the temporary support.

[0175] S54: Continuously perform dynamic simulation of the failure chain effect of the failure propagation network until no component in the failure propagation network is judged to be failed or the dynamic simulation process has completely covered all components in the time-varying structural topology diagram, and then end the dynamic simulation process.

[0176] The aforementioned dynamic simulation process ensures that no potential failure components are overlooked, nor does it involve meaningless infinite loops, thus fully capturing the final impact range of the failure chain reaction. Simultaneously, the final failure component and failure propagation path of each dynamic simulation are recorded as a complete failure chain reaction simulation result, providing single-round simulation data support for subsequent probability statistics.

[0177] S55: In each dynamic simulation, if more than a set number of components are judged to be ineffective or the mechanical transmission path is interrupted, the bridge is judged to be unstable during the dynamic simulation; otherwise, the bridge is judged not to be unstable during the dynamic simulation.

[0178] S56: Calculate the probability of dynamic instability of the bridge by counting the total number of dynamic simulations of the failure chain reaction and the number of times the bridge was determined to be unstable during the dynamic simulation.

[0179] The dynamic instability probability is obtained by dividing the number of times the bridge was identified as unstable during dynamic simulations by the total number of simulations. This probability directly quantifies the likelihood of overall bridge instability during the current construction phase, providing a clear quantitative basis for classifying construction safety risk levels and prioritizing control measures. For example, if the total number of dynamic simulations is preset to 1000, and 35 simulations are marked as indicating bridge instability, then the dynamic instability probability = 35 / 1000 = 0.035, or 3.5%. This result indicates a low probability of overall bridge instability during the current construction phase, corresponding to a low safety risk level, allowing for the maintenance of existing control measures and continuous monitoring. Furthermore, if 120 simulations are marked as indicating bridge instability, then the dynamic instability probability = 120 / 1000 = 0.12, or 12%, indicating a moderate overall instability risk. Immediate strengthening of control measures for key risk components and high-coupling connection paths is necessary to reduce the risk of cascading failures.

[0180] S6: Set different warning thresholds for different levels. Based on the relationship between the dynamic instability probability and the warning thresholds for different levels, trigger the corresponding level of bridge instability warning and generate optimized control strategies including construction sequence adjustment, temporary support reinforcement or construction suspension.

[0181] In this embodiment of the application, in order to avoid untimely or excessive early warnings, it is necessary to dynamically adjust the graded early warning thresholds in conjunction with the construction progress, synchronously trigger the corresponding level of early warnings and generate targeted optimized control strategies, so as to achieve effective management and handling of bridge construction safety risks.

[0182] Specifically, the dynamic adjustment of early warning thresholds at different levels should be centered on the construction progress and implemented gradually, taking into account the structural characteristics and safety requirements of each stage. First, the key progress nodes of bridge construction should be analyzed to identify the main stages, such as pile foundation, abutment, pier, beam erection, and temporary support removal, and to analyze the core construction content and risk characteristics of each stage. For example, the structural stability is relatively strong during the pile foundation construction stage, so the early warning thresholds can be more lenient; during the beam erection stage, risk transmission is rapid, so the early warning thresholds need to be tightened to improve early warning sensitivity.

[0183] Furthermore, baseline warning threshold ranges are set for each construction stage, and these thresholds are then adjusted based on real-time construction progress deviations, component installation status, and fluctuations in monitoring data. The baseline warning thresholds, referencing standards for similar projects and structural safety reserves, are categorized into four levels based on the probability of dynamic instability: blue warning (0, 0.2), yellow warning (0.2, 0.3), orange warning (0.3, 0.4), and red warning greater than 0.4. If the beam erection stage is completed 10% ahead of schedule and the stress fluctuations in key risk components are significant, the warning threshold for the yellow warning can be lowered to 0.18; if the delay in removing temporary supports leads to increased structural stress redundancy, the warning threshold for the red warning can be raised to 0.45.

[0184] Furthermore, once the dynamic instability probability is calculated, it is automatically compared with the warning thresholds for different levels of the current construction stage, triggering the corresponding level of warning and pushing information through multiple channels, thereby clarifying the warning level, dynamic instability probability, location of key risk components, and propagation path. For example, during the cantilever assembly stage of a continuous beam bridge, the dynamic instability probability is 0.33, exceeding the orange warning threshold of 0.3, immediately triggering an orange warning and indicating that the connection between cantilever segment #2 and the temporary support is a risk point.

[0185] Simultaneously, targeted optimization control strategies are generated. A blue alert (e.g., dynamic instability probability of 0.15) allows for fine-tuning of construction parameters, such as delaying the installation of component #4 by one day; a yellow alert (e.g., dynamic instability probability of 0.26) allows for reinforcement of temporary supports, adding two sets of Q355 steel diagonal supports on both sides of the critical risk component; an orange alert (e.g., dynamic instability probability of 0.36) requires adjusting the construction sequence and reinforcement, suspending cantilever assembly, and first performing prestressing tensioning on components #5 and #6; a red alert (e.g., dynamic instability probability of 0.48) immediately suspends construction, organizes personnel evacuation, and conducts a comprehensive risk assessment. For example, before the main span closure of a continuous steel structure bridge, the core critical risk component is the temporary locking device for the closure section. The dynamic classification warning thresholds for this stage are: blue alert 0.1-0.18, yellow alert 0.18-0.28, orange alert 0.28-0.38, and red alert ≥0.38. If the dynamic instability probability is 0.32, an orange alert will be triggered, and a targeted optimization control strategy will be generated: suspend the pouring of the closure section, adjust the pouring sequence to symmetrical pouring of the web, add 4 sets of 200mm×200mm shear supports at the temporary locking device, and resume construction after the supports are installed and the instability probability drops below 0.25.

[0186] like Figure 2 As shown, an early warning system for implementing the above-described BIM-based dynamic early warning method for bridge construction safety risks includes:

[0187] Time-varying topology generation module: used to acquire the BIM 3D structural model of the bridge construction and generate a sequence of time-varying structural topology diagrams based on the construction schedule information;

[0188] Risk component identification module: Based on the time-varying structural topology sequence and real-time collected construction monitoring data, it identifies key risk components in the current construction stage and forms a set of key risk components;

[0189] Stress evolution prediction module: Used to construct a local stress evolution model with the key risk component as the core for each key risk component in the key risk component set, and predict the stress state and stability coefficient of each component in the future preset construction sequence;

[0190] Coupling strength calculation module: used to calculate the risk coupling strength between components based on the predicted stability coefficients of each component and the spatial connection relationship in the time-varying structural topology diagram;

[0191] Instability probability calculation module: Used to simulate the failure chain effect of each component with the risk coupling strength as the link coefficient, and integrate the stability coefficient decay probability of the component to calculate the dynamic instability probability of the bridge.

[0192] Early warning strategy generation module: used to set early warning thresholds of different levels, and trigger bridge instability early warnings of the corresponding level based on the magnitude between the dynamic instability probability and the early warning thresholds of different levels, and generate optimized control strategies including construction sequence adjustment, temporary support reinforcement or construction suspension.

Claims

1. A BIM-based dynamic early warning method for bridge construction safety risks, characterized in that, Includes the following steps: S1: Obtain the BIM 3D structural model of the bridge construction and generate a time-varying structural topology sequence based on the construction schedule information to reflect the dynamic changes of completed components, temporary support components and connection relationships in each construction stage. S2: Based on the time-varying structural topology sequence and real-time collected construction monitoring data, identify the key risk components in the current construction stage and form a set of key risk components; S3: For each critical risk component in the critical risk component set, construct a local stress evolution model with the critical risk component as the core, and predict the stress state and stability coefficient of each component in the future preset construction sequence. S4: Calculate the risk coupling strength between components based on the predicted stability coefficients of each component and the spatial connectivity in the time-varying structural topology diagram; S5: Using the risk coupling strength as the link coefficient, simulate the failure chain effect of each component, and integrate the stability coefficient decay probability of the component to calculate the dynamic instability probability of the bridge. S6: Set different warning thresholds for different levels. Based on the magnitude between the dynamic instability probability and the warning thresholds for different levels, trigger the corresponding level of bridge instability warning and generate optimized control strategies including construction sequence adjustment, temporary support reinforcement or construction suspension. Step S3 includes: S31: Based on the time-varying structural topology diagram of the current construction stage, extract the current geometric boundary conditions, mechanical connection status and related component information of key risk components; S32: Obtain construction load time sequence distribution data, temporary facility dismantling sequence, and time-varying mechanical parameters of materials related to critical risk components; S33: Based on the mechanical connection state and related component information, establish a simplified mechanical model with key risk components as the core, as a local force evolution model. The geometric boundary conditions of the simplified mechanical model are set according to the mechanical transmission path. S34: Using the construction load time sequence distribution data, temporary facility dismantling time sequence, and material time-varying mechanical parameters as time-varying input conditions, the parameters of the local stress evolution model are gradually updated according to the future preset construction steps. S35: Through iterative calculation, predict the stress state of the component at the end of each future preset construction step, and calculate the stability coefficient of the component under the current construction step based on the predicted stress state and the time-varying mechanical parameters of the material. S36: Summarize the stress states predicted by all future preset construction steps, and output the stress states and stability coefficients of the component as it evolves in the sequence of future preset construction steps; The method for calculating the stability coefficient under the current construction sequence specifically includes: S351: Obtain the allowable stress and elastic modulus of the material of the component under the current construction step; extract the equivalent stress value of the control section of the component under the current construction step from the stress state output by the local stress evolution model; S352: Select the appropriate stability coefficient calculation criterion based on the stress type and failure mode of the component; output the stability coefficient of the component; Step S4 includes: S41: Obtain all directly connected component pairs in the current construction phase from the time-varying structural topology diagram; S42: For each pair of directly connected components, read the stability coefficient and topological criticality index of each of the two components in the pair, and then realize the basic data fusion of the component's own safety status and the degree of topological coreness. S43: Calculate the risk factors of the two components separately, and add the risk factors of the two components together to obtain the risk coupling strength between the component pair; the risk factor is the ratio of the topological criticality index to the stability coefficient of the component. Step S5 includes: S51: Taking the critical risk components in the critical risk component set as the initial failure trigger point, establish a failure propagation network between components based on the spatial connection relationship and mechanical transmission path defined in the time-varying structural topology diagram, and obtain the core starting point and connection path of failure propagation. S52: Use the risk coupling strength as the link coefficient of the corresponding connection path in the failure propagation network; S53: Starting from each initial failure trigger point, the propagation process of the failure state is recursively simulated based on the connection path and link coefficient of the failure propagation network, and the failure chain effect is dynamically deduced. During the dynamic simulation, the critical threshold for instability of the component is set, and the attenuation probability coefficient is calculated based on the risk coupling strength. Then, the attenuation probability of the stability coefficient is calculated based on the stability coefficient, the critical threshold for instability, and the attenuation probability coefficient of the component. If the probability of stability coefficient decay is greater than 1, the component is determined to be faulty; otherwise, the component is determined not to be faulty. When one of the components is determined to be faulty, the stability coefficient of its adjacent components is reduced proportionally according to the link coefficient of the corresponding connection path. Specifically, the formula for calculating the reduced stability coefficient of adjacent components is: Reduced stability coefficient = Original stability coefficient of the structure × (1 - Risk coupling strength / Strength normalization factor); S54: Continuously perform dynamic simulation of the failure chain effect of the failure propagation network until no component in the failure propagation network is judged to be failed or the dynamic simulation process has completely covered all components in the time-varying structural topology diagram, and then end the dynamic simulation process. S55: In each dynamic simulation, if more than a set number of components are judged to be ineffective or the mechanical transmission path is interrupted, the bridge is judged to be unstable during the dynamic simulation; otherwise, the bridge is judged not to be unstable during the dynamic simulation. S56: Calculate the dynamic instability probability of the bridge by the total number of dynamic simulations of the failure chain reaction and the number of times the bridge was determined to be unstable during the dynamic simulation; divide the number of times the bridge was determined to be unstable during the dynamic simulation by the total number of dynamic simulations. The formula for the attenuation probability coefficient is: Attenuation probability coefficient = type base value + risk coupling strength × adjustment coefficient; The formula for calculating the stability coefficient decay probability is: stability coefficient decay probability = decay probability coefficient × (instability critical threshold / stability coefficient).

2. The BIM-based dynamic early warning method for bridge construction safety risks according to claim 1, characterized in that, Step S1 includes: S11: Extract the geometric information, attribute information and initial topological connection relationship of all components from the BIM three-dimensional structural model of bridge construction. The components include permanent components and temporary support components. S12: Analyze the construction schedule information, obtain the component construction sequence in units of construction stages, obtain the planned installation completion time and status of each component; and analyze the time pattern of component commissioning during construction to establish the time correlation between structural changes and construction progress. S13: Associate the planned installation completion time of the component with the component in the BIM 3D structural model to establish a mapping relationship between the component and the construction phase; S14: Based on the component-construction stage mapping relationship, generate a time-varying structural topology diagram for each construction stage. Each time-varying structural topology diagram includes the components that have been planned to be built in the current construction stage and previous construction stages, the effective temporary support components in the current stage, and the connection relationships. S15: Based on the component type and the initial topological connection relationship, define and update the spatial connection relationship and mechanical transmission path between components in each time-varying structural topology diagram to form a complete sequence of time-varying structural topology diagrams.

3. The BIM-based dynamic early warning method for bridge construction safety risks according to claim 2, characterized in that, Step S2 includes: S21: Extract the time-varying structural topology map corresponding to the current construction stage from the time-varying structural topology map sequence, filter out all completed components that are under stress, and form a set of components to be evaluated; S22: For each component in the set of components to be evaluated, collect real-time monitored stress and displacement values, and calculate the historical stress change rate based on historically monitored stress values; S23: Based on the spatial connection relationship of each component in the set of components to be evaluated, obtain the displacement value of adjacent components in real time and calculate the deformation compatibility with adjacent components; S24: Based on the spatial connection relationship of each component in the time-varying structural topology diagram in the set of components to be evaluated, evaluate the key topological indicators and clarify the core degree and influence weight of the components in the overall bridge structure. S25: Set thresholds for stress history rate of change, deformation compatibility, and topological criticality indices for different types of components. If the stress history rate of change of a component exceeds the stress history rate of change threshold, the deformation compatibility is lower than the deformation compatibility threshold, or the topological criticality index exceeds the topological criticality index threshold, then the component is determined to be a critical risk component; otherwise, the component is determined to be a non-critical risk component. S26: Obtain all critical risk components in the set of components to be evaluated, and then construct the set of critical risk components in the current construction phase.

4. The BIM-based dynamic early warning method for bridge construction safety risks according to claim 3, characterized in that, The specific method for evaluating the key topological indicators is as follows: S241: In the time-varying structural topology diagram corresponding to the current construction stage, count the number of directly connected adjacent components in the set of components to be evaluated, and use this as the topological connectivity of the components. S242: Based on the initial topological connection relationship and the mechanical transmission path defined in the time-varying structural topology diagram, determine whether the component is located on the critical force transmission path from the main construction load application point to the foundation support. If so, the judgment value of the critical force transmission path is assigned to 1; otherwise, the judgment value of the critical force transmission path is assigned to 0. S243: Assign preset type weight coefficients to permanent components and temporary support components based on their type; S244: Based on the topological connectivity, the judgment value of the critical force transmission path, and the type weight coefficient, a weighted calculation is performed to obtain the topological criticality index of the component. The formula for calculating the topology criticality index is: Topology criticality index = 0.3 × Topology connectivity + 0.5 × Judgment value of critical force transmission path + 0.2 × Type weight coefficient.

5. An early warning system for implementing the BIM-based dynamic early warning method for bridge construction safety risks as described in any one of claims 1-4, characterized in that, include: Time-varying topology generation module: used to acquire the BIM 3D structural model of the bridge construction and generate a sequence of time-varying structural topology diagrams based on the construction schedule information; Risk component identification module: Based on the time-varying structural topology sequence and real-time collected construction monitoring data, it identifies key risk components in the current construction stage and forms a set of key risk components; Stress evolution prediction module: Used to construct a local stress evolution model with the key risk component as the core for each key risk component in the key risk component set, and predict the stress state and stability coefficient of each component in the future preset construction sequence; Coupling strength calculation module: used to calculate the risk coupling strength between components based on the predicted stability coefficients of each component and the spatial connection relationship in the time-varying structural topology diagram; Instability probability calculation module: Used to simulate the failure chain effect of each component with the risk coupling strength as the link coefficient, and integrate the stability coefficient decay probability of the component to calculate the dynamic instability probability of the bridge. Early warning strategy generation module: used to set early warning thresholds of different levels, and trigger bridge instability early warnings of the corresponding level based on the magnitude between the dynamic instability probability and the early warning thresholds of different levels, and generate optimized control strategies including construction sequence adjustment, temporary support reinforcement or construction suspension.

Images