Method for evaluating state of concrete-filled steel tube tied arch bridge

Abstract

The invention relates to the field of bridge engineering and structure health monitoring, in particular to a method for evaluating the state of a concrete-filled steel tube tied arch bridge. The method comprises the steps of calculating node deformation based on vertical displacement of nodes, and further calculating internal force of bridge components; a nonlinear damage index model is introduced, and the damage index of the bridge component is calculated by combining the internal force of the bridge component and the node deformation amount; based on the damage index of the bridge component, the damage grade of the bridge component is evaluated; calculating dynamic response characteristics of the nodes based on the node deformation; and constructing a bridge health assessment model based on the dynamic response characteristics of the nodes, the node deformation and the internal force of the bridge component, and assessing the health state of the bridge. The problems that an existing bridge health assessment method generally depends on a simplified linear model, mostly neglects the space-time coupling effect between nodes of a bridge, and the influence of environmental factors is not effectively considered, so that the accuracy and reliability of an assessment result are poor are solved.

Description

Technical Field

[0001] The invention relates to the field of bridge engineering and structural health monitoring, and in particular to a state assessment method for a steel tube concrete tied arch bridge. Background Art

[0002] With the improvement of sensor technology and data processing capabilities, more and more bridges have begun to use real-time monitoring systems to collect multi-dimensional data such as vibration, deformation, temperature, and humidity, and then use data analysis methods to evaluate the health status of bridges. In particular, in terms of dynamic response monitoring, technologies based on accelerometers and displacement sensors have been widely used to capture the vibration characteristics of bridges in real time and infer the health status of bridge structures through vibration response analysis. In addition, the advancement of finite element analysis and multi-physics field simulation technology has made bridge health assessment more accurate, and can simulate and predict bridge responses under different working conditions, thereby improving the accuracy and reliability of the assessment.

[0003] However, there are still some key problems to be solved in the existing technology in bridge health assessment. For example, the existing bridge health assessment methods usually rely on simplified linear models, and most of them ignore the spatiotemporal coupling effects between various nodes of the bridge, and fail to effectively consider the influence of environmental factors, resulting in poor accuracy and reliability of the assessment results. Therefore, it is urgent to provide a bridge health status assessment method that can solve the above problems. Summary of the invention

[0004] The present invention provides a state assessment method for a steel tube concrete tied arch bridge to solve the problem that the existing bridge health assessment methods usually rely on simplified linear models, fail to effectively capture the nonlinear relationship between the internal force of the bridge structure and the node deformation, so that the assessment results often cannot truly reflect the actual damage of the bridge; most of the existing bridge health assessment methods ignore the spatiotemporal coupling effect between various nodes of the bridge, especially the complex interaction between the node deformation and the vibration response, resulting in the problem that the health state of the bridge cannot be accurately assessed when facing dynamic loads or environmental changes; and fail to effectively consider the influence of environmental factors, resulting in poor accuracy and reliability of the assessment results.

[0005] A method for evaluating the state of a steel tube concrete tied arch bridge comprises the following steps: S1: Collect the vertical displacement of the node and calculate the node deformation based on the vertical displacement of the node; calculate the internal force of the bridge component based on the node deformation; introduce a nonlinear damage index model to calculate the damage index of the bridge component by combining the internal force and node deformation of the bridge component; evaluate the damage level of the bridge component based on the damage index of the bridge component; S2: Based on the node deformation, the dynamic response characteristics of the node are calculated using the time-space coupled dynamic response evaluation method; a bridge health assessment model is constructed based on the dynamic response characteristics of the node, the node deformation and the internal forces of the bridge components to evaluate the health status of the bridge.

[0006] Preferably, the S1 specifically includes: In the process of calculating the node deformation, a weighting factor is introduced to evaluate the importance of each node; the node deformation calculation formula is as follows: , in, Indicates The node deformation of each node; is the index variable of the node; It is The weighting factor of each node; is the total number of nodes participating in the calculation; and is the index variable of the node; It represents a node and nodes The coupling coefficient between It is a node collected by sensors The vertical displacement of is the adjustment coefficient; It represents a node and nodes The coupling coefficient between It is a node collected by sensors vertical displacement.

[0007] Preferably, the S1 specifically includes: The internal force of the bridge component is calculated through the relationship between the node deformation and the mechanical properties of the bridge component. The specific calculation formula is: , in, Indicates Internal forces of bridge components; is the index variable of the bridge component; It is a bridge component The number of nodes involved; It acts on External loads on nodes; It is with The length of the bridge component associated with each node; It is Node pair The contribution coefficient of the internal force of each bridge component is calculated based on the geometry and mechanical properties of the bridge structure and the coupling relationship between the nodes.

[0008] Preferably, the S1 specifically includes: The nonlinear damage index model evaluates the damage state of bridge components by combining the nonlinear relationship between the internal force and node deformation of bridge components, and controls the influence of node deformation on damage by adjusting the influence coefficient of node deformation on the damage of bridge components.

[0009] Preferably, the S1 specifically includes: The damage state refers to the health of bridge components under load, which is quantified by the damage index calculated by the nonlinear damage index model; the damage index formula is as follows: , in, Indicates Damage index of each bridge component; is the influence coefficient of the internal force difference of bridge components on damage; Indicates Initial internal forces of each bridge component; is the influence coefficient of node deformation on the damage of bridge components; It is The node deformation of each node; It is the adjustment factor of the cumulative effect of node deformation on damage.

[0010] Preferably, the S1 specifically includes: The damage intervals are divided into healthy state interval, slight damage interval, moderate damage interval and severe damage interval. The damage level of the bridge components is evaluated by comparing the damage index and damage interval of the bridge components.

[0011] Preferably, the S2 specifically includes: There is a spatiotemporal correlation between the vibration response of the bridge and the node deformation. Based on the spatiotemporal correlation, a spatiotemporal coupling dynamic response evaluation method is proposed. The dynamic response characteristics of the nodes are calculated by combining the vibration response of the bridge and the node deformation. The vibration response of the bridge is the inherent vibration characteristic of the bridge structure.

[0012] Preferably, the S2 specifically includes: In the process of implementing the bridge health assessment model, an environmental correction factor is introduced to compensate for the impact caused by environmental changes; the formula of the bridge health assessment model is as follows: , in, is the health assessment value of the bridge; is the weighting coefficient of the node's weighted node deformation for health status assessment; is the total number of nodes participating in the calculation; is the index variable of the node; It is The weighting factor of each node; Indicates The node deformation of each node at the current moment; is the weighting coefficient of the internal forces of bridge components for the assessment of bridge health status; is the total number of bridge components; is the index variable of the bridge component; It is Weighting factors for each bridge component; Indicates Internal forces of bridge components; is the weighting coefficient of the dynamic response characteristics for the assessment of bridge health status; It is The dynamic response characteristics of each node at the current moment; is the environmental correction factor; is the adjustment coefficient of temperature to the environmental correction factor; is the difference between the current ambient temperature and the reference temperature; It is the difference between the current ambient humidity and the reference humidity.

[0013] Preferably, the S2 specifically includes: Set a bridge health range. When the bridge health assessment value is within the bridge health range, it means that the bridge is in good condition and regular inspections and monitoring should continue. When the bridge health assessment value is not within the bridge health range, further inspection of the bridge should be carried out to confirm whether there is any damage or abnormality, and appropriate response measures should be taken as appropriate.

[0014] The beneficial effects of the technical solution of the present invention are: 1. Based on the node deformation and the internal force of the bridge components, the nonlinear damage index model is used to quantitatively evaluate the damage status of the bridge components, effectively improving the accuracy and reliability of damage assessment.

[0015] 2. By combining the node deformation and the vibration response of the bridge and calculating the dynamic response characteristics, the accuracy of the bridge health status assessment is further enhanced, so that the bridge health status assessment results can fully reflect the health status of the bridge.

[0016] 3. By combining the dynamic response characteristics, node deformation and internal forces of bridge components, a more comprehensive bridge health assessment model is constructed, and environmental correction factors are introduced to comprehensively consider the impact of environmental factors such as temperature and humidity on the bridge health status assessment results. Changes in temperature and humidity will affect the stress and deformation of the bridge structure. Adjusting the bridge health assessment model through environmental correction factors can effectively reduce the errors caused by environmental changes and improve the accuracy of bridge health status assessment results. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention provides a flow chart of a method for assessing the state of a steel tube concrete tied arch bridge. DETAILED DESCRIPTION

[0018] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0020] The specific scheme of the state assessment method of a steel tube concrete tied arch bridge provided by the present invention is described in detail below with reference to the accompanying drawings.

[0021] Refer to the attached Figure 1 , which shows a flow chart of a method for assessing the state of a steel tube concrete tied arch bridge provided by an embodiment of the present invention, the method comprising the following steps: S1: Collect the vertical displacement of the node and calculate the node deformation based on the vertical displacement of the node; calculate the internal force of the bridge component based on the node deformation; introduce a nonlinear damage index model to calculate the damage index of the bridge component by combining the internal force and node deformation of the bridge component; evaluate the damage level of the bridge component based on the damage index of the bridge component.

[0022] First, sensors are installed at monitoring points in the bridge structure to collect deformation data of each monitoring point, that is, the vertical displacement of the node. Nodes are monitoring points in the bridge structure, such as arch feet, support points, and bridge deck joints, which are parts that bear large loads. The specific location is set according to the specific implementation scenario. The vertical displacement of the collected nodes is used to reflect the deformation of the bridge under load.

[0023] Furthermore, the node deformation is calculated using the vertical displacement of the node, which is used to evaluate the health status of the node. In order to accurately evaluate the relative importance of each node, the node deformation is adjusted using a weighting factor. The weighting factor ensures that the deformation of key parts has a more prominent impact on the overall evaluation results, thereby improving the accuracy of the bridge health status assessment.

[0024] The node deformation is calculated by the following formula: , in, Indicates The node deformation of each node reflects the degree of deformation of the node under the load of the bridge; is the index variable of the node; It is The weighting factor of each node indicates the importance of the node to the overall assessment result in the health status assessment, which can be set according to factors such as the stress condition of the node in the specific implementation scenario, the sensitivity of deformation to the bridge structure, and the location; is the total number of nodes participating in the calculation; and is the index variable of the node; It represents a node and nodes The coupling coefficient between the nodes is set by expert experience method, combining the mechanical characteristics of the bridge structure and the relationship between the nodes, reflecting the and nodes The mechanical coupling effect between them; It is a node collected by sensors The vertical displacement represents the actual deformation of each monitoring point; is the adjustment coefficient, which is set according to the specific implementation scenario; It represents a node and nodes The coupling coefficient between the nodes is set by expert experience method, combining the mechanical characteristics of the bridge structure and the relationship between the nodes, reflecting the and nodes The mechanical coupling effect between them; It is a node collected by sensors vertical displacement.

[0025] Furthermore, the internal forces of bridge components are calculated based on the node deformation. Each bridge component is connected to multiple nodes, and the node deformation reflects the stress of the corresponding bridge component. The internal forces of bridge components are calculated based on the relationship between the node deformation and the mechanical properties of bridge components.

[0026] The internal force calculation formula of each bridge component is: , in, Indicates Internal forces of bridge components; is the index variable of the bridge component; It is a bridge component The number of nodes involved; is the index variable of the node; It acts on The external loads on each node are set by expert experience based on factors such as bridge design specifications, traffic flow, and environmental conditions (such as wind and temperature changes). It is The node deformation of each node; It is with The length of the bridge components related to each node can be obtained through bridge design drawings or structural modeling tools; It is Node pair The contribution coefficient of the internal force of each bridge component is calculated by existing technologies, such as finite element analysis or empirical methods, based on the geometry and mechanical characteristics of the bridge structure and the coupling relationship between nodes; Furthermore, a nonlinear damage index model is introduced to evaluate the damage state of bridge components. The nonlinear damage index model evaluates the damage state of bridge components by combining the nonlinear relationship between the internal force and node deformation of bridge components, and controls the influence of node deformation on damage by adjusting the influence coefficient of node deformation on the damage of bridge components, thereby improving the accuracy and reliability of damage state assessment. The damage state refers to the health state of bridge components under load, which is quantified by the damage index calculated by the nonlinear damage index model. The smaller the damage index, the more serious the damage to the bridge component and the worse the bearing capacity; while the larger the damage index, the better the health state of the bridge component.

[0027] The damage index formula is as follows: , in, Indicates Damage index of each bridge component; is the index variable of the bridge component; Indicates Internal forces of bridge components; Indicates The initial internal force of each bridge component is set using expert experience during bridge design. It represents the normal internal force value of the bridge component in an undamaged state and is used to help determine the extent of damage. It is the influence coefficient of the internal force difference of bridge components on the damage, which is used to control the influence degree of the internal force difference of bridge components on the damage index and is set according to the specific implementation scenario; It is the influence coefficient of node deformation on the damage of bridge components. It is used to control the contribution of node deformation to the damage index and is set according to the specific implementation scenario. It is a bridge component The number of nodes involved; is the index variable of the node; It is Node pair Contribution coefficient of internal force of each bridge component; It is The node deformation of each node; It is the adjustment factor of the cumulative effect of node deformation on damage, which is used to control the influence of the cumulative effect of node deformation on the damage index of bridge components. The value will make the effect of node deformation on damage more significant.

[0028] The damage intervals are divided according to the specific implementation scenarios, such as healthy status interval, slight damage interval, moderate damage interval, and severe damage interval. By comparing the damage index of bridge components with the preset damage intervals, the damage level of bridge components is evaluated, helping engineers to take timely maintenance and reinforcement measures to ensure the safe use of the bridge.

[0029] S2: Based on the node deformation, the dynamic response characteristics of the node are calculated using the time-space coupled dynamic response evaluation method; a bridge health assessment model is constructed based on the dynamic response characteristics of the node, the node deformation and the internal forces of the bridge components to evaluate the health status of the bridge.

[0030] There is a certain spatiotemporal correlation between the vibration response of a bridge and the local deformation, which is the node deformation. In practical applications, the change of the vibration response of a bridge is closely related to the local deformation of the bridge node, and is affected by both time and space distribution. Based on the spatiotemporal correlation, a spatiotemporal coupled dynamic response evaluation method is proposed. The dynamic response characteristics of the node are calculated by combining the vibration response of the bridge and the node deformation to evaluate the health status of the bridge. The vibration response of a bridge refers to the inherent vibration characteristics of the bridge structure. The dynamic response characteristics of the node are jointly determined by the vibration response of the bridge and the influence of the node deformation. Specifically, the dynamic response characteristics of the node are not only affected by the inherent vibration characteristics of the bridge structure, such as amplitude, attenuation coefficient and vibration frequency, but also by the node deformation.

[0031] The calculation formula of the dynamic response characteristics of the node is as follows: , in, It is The dynamic response characteristics of each node at the current moment; is a time index variable, used to represent the current moment; represents the vibration response of the bridge, is the initial amplitude of the vibration; is the vibration attenuation factor, reflecting the decay of vibration amplitude over time as energy is dissipated; is the basic attenuation coefficient of the vibration attenuation factor; is the cosine function; is the angular frequency of the vibration, reflecting the periodicity of the vibration; the initial amplitude of the vibration , basic attenuation coefficient of vibration attenuation factor , angular frequency of vibration Set according to specific implementation scenarios; Indicates The influence of the node deformation of each node at the current moment on the dynamic response characteristics; is the vibration sensitivity coefficient, which indicates the influence of node deformation on dynamic response characteristics and is set according to the specific implementation scenario; Indicates The node deformation of each node at the current moment; is a correction term, using the weighted node deformation of the node make corrections; It is the smoothing coefficient, which is used to adjust the degree of correction of the weighted node deformation to the dynamic response characteristics to avoid affecting the overall evaluation results. It is set according to the specific implementation scenario; is the total number of nodes participating in the calculation; is the index variable of the node; It is The weighting factor of the node.

[0032] A bridge health assessment model is constructed by integrating the dynamic response characteristics of nodes, node deformation and internal forces of bridge components to evaluate the overall health status of the bridge. In order to further improve the accuracy of bridge health status assessment, an environmental correction factor is introduced to adapt to the impact of environmental factors such as temperature and humidity on the health status assessment results and compensate for the impact caused by environmental changes, thereby improving the accuracy of the health status assessment results.

[0033] The formula of the bridge health assessment model is as follows: , in, is the health assessment value of the bridge, which is calculated based on the data of the currently sampled sensors and is used to quantitatively assess the health status of the bridge; It is the weighting coefficient of the weighted node deformation of the node on the health status assessment, which is used to control the influence of the weighted node deformation of the node on the health status assessment of the bridge and is set according to the expert experience method; is the total number of nodes participating in the calculation; is the index variable of the node; It is The weighting factor of each node; It is the weighting coefficient of the internal force of bridge components on the bridge health status assessment, which is used to control the influence of the internal force of bridge components on the bridge health status assessment and is set according to the expert experience method; is the total number of bridge components; is the index variable of the bridge component; It is The weighting factor of each bridge component is used to reflect the The importance of each bridge component is set according to the specific implementation scenario; Indicates Internal forces of bridge components; is the weighting coefficient of the dynamic response characteristics to the bridge health status assessment, which is used to indicate the contribution of the dynamic response characteristics to the bridge health status assessment; It is The dynamic response characteristics of each node at the current moment; is the environmental correction factor, which is used to adjust the impact of environmental changes on the bridge health assessment model; It is the adjustment coefficient of temperature to environmental correction factor, which is set by expert experience method; is the difference between the current ambient temperature and the reference temperature; It is the difference between the current ambient humidity and the reference humidity; the reference temperature and reference humidity are set according to the specific implementation scenario.

[0034] Finally, the bridge health range is set according to the specific implementation scenario. When the bridge health assessment value is within the bridge health range, it means that the bridge is in good condition. At this time, regular inspections and monitoring can be continued to ensure the stability of the bridge structure. If the bridge health assessment value is not within the bridge health range, the bridge needs to be further inspected to confirm whether there is damage or abnormality. At the same time, according to the specific situation, appropriate maintenance, reinforcement or other response measures are taken to ensure the safety of the bridge.

[0035] In summary, a condition assessment method for concrete-filled steel tube tied arch bridges was completed.

[0036] The order of the embodiments of the invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0037] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A method for evaluating the state of a steel tube concrete tied arch bridge, characterized in that: The following steps are involved: S1: Collect the vertical displacement of the node and calculate the node deformation based on the vertical displacement of the node; calculate the internal force of the bridge component based on the node deformation; introduce a nonlinear damage index model to calculate the damage index of the bridge component by combining the internal force and node deformation of the bridge component; evaluate the damage level of the bridge component based on the damage index of the bridge component; S2: Based on the node deformation, the dynamic response characteristics of the node are calculated using the time-space coupled dynamic response evaluation method; a bridge health assessment model is constructed based on the dynamic response characteristics of the node, the node deformation and the internal forces of the bridge components to evaluate the health status of the bridge.

2. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 1, characterized in that: The S1 specifically includes: In the process of calculating the node deformation, a weighting factor is introduced to evaluate the importance of each node; the node deformation calculation formula is as follows: ， in, Indicates The node deformation of each node; is the index variable of the node; It is The weighting factor of each node; is the total number of nodes participating in the calculation; and is the index variable of the node; It represents a node and nodes The coupling coefficient between It is a node collected by sensors The vertical displacement of is the adjustment coefficient; It represents a node and nodes The coupling coefficient between It is a node collected by sensors vertical displacement.

3. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 2, characterized in that: The S1 specifically includes: The internal force of the bridge component is calculated through the relationship between the node deformation and the mechanical properties of the bridge component. The specific calculation formula is: ， in, Indicates Internal forces of bridge components; is the index variable of the bridge component; It is a bridge component The number of nodes involved; It acts on External loads on nodes; It is with The length of the bridge component associated with each node; It is Node pair The contribution coefficient of the internal force of each bridge component is calculated based on the geometry and mechanical properties of the bridge structure and the coupling relationship between the nodes.

4. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 3 is characterized in that: The S1 specifically includes: The nonlinear damage index model evaluates the damage state of bridge components by combining the nonlinear relationship between the internal force and node deformation of bridge components, and controls the influence of node deformation on damage by adjusting the influence coefficient of node deformation on the damage of bridge components.

5. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 4, characterized in that: The S1 specifically includes: The damage state refers to the health of bridge components under load, which is quantified by the damage index calculated by the nonlinear damage index model; the damage index formula is as follows: ， in, Indicates Damage index of each bridge component; is the influence coefficient of the internal force difference of bridge components on damage; Indicates Initial internal forces of each bridge component; is the influence coefficient of node deformation on the damage of bridge components; It is The node deformation of each node; It is the adjustment factor of the cumulative effect of node deformation on damage.

6. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 5, characterized in that: The S1 specifically includes: The damage intervals are divided into healthy state interval, slight damage interval, moderate damage interval and severe damage interval. The damage level of the bridge components is evaluated by comparing the damage index and damage interval of the bridge components.

7. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 1, characterized in that: The S2 specifically includes: There is a spatiotemporal correlation between the vibration response of the bridge and the node deformation. Based on the spatiotemporal correlation, a spatiotemporal coupling dynamic response evaluation method is proposed. The dynamic response characteristics of the nodes are calculated by combining the vibration response of the bridge and the node deformation. The vibration response of the bridge is the inherent vibration characteristic of the bridge structure.

8. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 7, characterized in that: The S2 specifically includes: In the process of implementing the bridge health assessment model, an environmental correction factor is introduced to compensate for the impact caused by environmental changes; the formula of the bridge health assessment model is as follows: ， in, is the health assessment value of the bridge; is the weighting coefficient of the node's weighted node deformation for health status assessment; is the total number of nodes participating in the calculation; is the index variable of the node; It is The weighting factor of each node; Indicates The node deformation of each node at the current moment; is the weighting coefficient of the internal forces of bridge components for the assessment of bridge health status; is the total number of bridge components; is the index variable of the bridge component; It is Weighting factors for each bridge component; Indicates Internal forces of bridge components; is the weighting coefficient of the dynamic response characteristics for the assessment of bridge health status; It is The dynamic response characteristics of each node at the current moment; is the environmental correction factor; is the adjustment coefficient of temperature to the environmental correction factor; is the difference between the current ambient temperature and the reference temperature; It is the difference between the current ambient humidity and the reference humidity.

9. The method for evaluating the state of a steel tube concrete tied arch bridge according to claim 8, characterized in that: The S2 specifically includes: Set a bridge health range. When the bridge health assessment value is within the bridge health range, it means that the bridge is in good condition and regular inspections and monitoring should continue. When the bridge health assessment value is not within the bridge health range, further inspection of the bridge should be carried out to confirm whether there is any damage or abnormality, and appropriate response measures should be taken as appropriate.

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