Dynamic monitoring method for risk coefficient of bearing capacity of cross section of bridge structure

Abstract

The invention discloses a dynamic monitoring method for a bridge structure section bearing capacity risk coefficient, and the method comprises the following steps: obtaining a structure internal force-deflection fitting curve and a threshold value of the fitting curve through obtaining the deflection and the structure internal force of a bridge structure section response calculation point under the action of vehicle spatial and temporal distribution at a first moment; obtaining and calculating vehicle space-time distribution data in a second time period to obtain structural internal force-deflection curves, comparing slopes of the two structural internal force-deflection curves in the first time period and the second time period, and making a difference; and if the difference value is greater than the set value, indicating that the bearing capacity of the cross section of the bridge structure is abnormal at the moment, and outputting vehicle space-time distribution data of the cross section of the bridge structure at the abnormal moment. And the real-time bearing capacity risk coefficient of the bridge is output through the bearing capacity standard value of the section.

Description

Technical Field

[0001] The invention belongs to the field of monitoring the risk coefficient of the cross-section bearing capacity of a bridge beam structure, and in particular, relates to a dynamic monitoring method for the risk coefficient of the cross-section bearing capacity of a bridge structure. Background Art

[0002] Existing urban and highway bridges generally lack structural safety and health monitoring. For bridges that have been equipped with structural health monitoring systems,

[0003] There is no technical research related to the bearing capacity risk coefficient in the existing bridge structure cross-section monitoring. The existing technology mainly relies on finite element software to analyze the bridge structure, combines the monitoring response values ​​of the measuring points for interpolation analysis, and calculates the structural internal force through the material constitutive model. It requires human intervention and lacks applicability for real-time early warning in dynamic monitoring scenarios of bridges.

[0004] The existing technology uses the finite element method to calculate the internal forces of the section. The calculation time is long, it is difficult to provide timely feedback, and there is a lag. At the same time, the calculation frequency of the finite element calculation is low, and it requires a lot of manpower. The analysis results can be used to judge the changes in the bearing capacity of the bridge, but it is difficult to use it to guide the traffic control on the bridge site. It only obtains the structural response of the bridge, and lacks the output of the current bridge deck vehicle load conditions.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The technical problem to be solved by the present invention is to solve the dynamic monitoring of the risk factor of the cross-section bearing capacity of the bridge beam structure. In order to solve the above technical problem, the specific technical solution adopted by the present invention is:

[0007] 1. A dynamic monitoring method for the risk factor of the cross-section bearing capacity of a bridge structure comprises the following steps:

[0008] S1. Obtaining the spatiotemporal distribution data of vehicles at the first moment, the spatiotemporal distribution data of vehicles at least including weighing time, lane, vehicle speed, number of axles, axle weight, wheelbase, and obtaining the deflection of any response calculation point of the bridge structure section at the first moment;

[0009] S2, using the time-space distribution data of the vehicles to respectively calculate the structural internal force of the same response calculation point of the bridge structure section and the deflection at the first moment;

[0010] S3, taking multiple moments within the first period of time to obtain multiple structural internal force-deflection scatter points, and obtaining a structural internal force-deflection fitting curve and a threshold value of the fitting curve from the scatter points;

[0011] S4, obtaining the time-space distribution data of vehicles in the second time period, calculating the structural internal force and deflection of the cross section of the bridge structure in the second time period and forming a structural internal force-deflection curve;

[0012] Subtract the slope value of the structural internal force-deflection fitting curve in the first time period from the slope value of the structural internal force-deflection fitting curve in the second time period;

[0013] If the difference in the slopes of the two structural internal force-deflection fitting curves is greater than a set value, it indicates that the bearing capacity of the bridge structure section in the second time period is abnormal, and the vehicle spatiotemporal distribution information of the bridge structure section at the abnormal moment is output in real time.

[0014] S5. judging whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed a threshold value through a fitting curve of the structural internal force-deflection in the first time period;

[0015] If the internal force and deflection of the structure at that moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal and the bearing capacity risk coefficient is output in real time.

[0016] Furthermore, by obtaining the design value My of the mid-span bending moment bearing capacity of the bridge under the time-space distribution of vehicles at the first moment and the mid-span bending moment value Ma under the vehicle load condition, the bearing capacity risk coefficient Ma / My is calculated.

[0017] Furthermore, according to the bridge structure design calculation book, the design value of the bridge mid-span bending moment bearing capacity My (taking the mid-span positive bending moment as an example) can be input. If there is no relevant data, it can be calculated according to the standard design load, and the My value can be calculated by combining the influence line function and the design load value. The uniformly distributed load is the equivalent fleet load. The bearing capacity calculation of this part can be calculated by taking the product of the influence line integral and the uniformly distributed load size;

[0018] According to the relevant provisions of JTG D60-2015 "General Specifications for Highway Bridge and Culvert Design" on lane design loads, the design values ​​of uniformly distributed loads and concentrated loads are determined according to the span and highway grade;

[0019] The reduction factor needs to be considered for multi-lane vehicle loading. According to the relevant provisions of JTG D60-2015 "General Specifications for Highway Bridge and Culvert Design" on lane design loads, the load layout reduction factor is determined based on the number of transverse lanes and the longitudinal calculated span.

[0020] Furthermore, a risk warning is provided at any time in the second time period through the bearing capacity risk coefficient;

[0021] When the bearing capacity risk coefficient is greater than a set value, it is judged that the cross section of the bridge structure is abnormal at that moment and an alarm is issued. The present invention introduces the bearing capacity risk coefficient into dynamic monitoring to realize trend visualization and real-time warning;

[0022] When the risk coefficient is less than 0, it means that at this moment, the vehicle load is mainly concentrated in the adjacent span of the measuring point, and the bending moment of the monitoring point section is negative. Considering the dead weight of the bridge itself and the negative bending moment value caused by the adjacent span is generally small, it is relatively safe; the risk coefficient is equal to 0, which means that there is no vehicle passing through the calculated span bridge deck at this moment, and the internal force of the measuring point section caused by the vehicle is 0; the part with a risk coefficient greater than 0 is the focus of the algorithm output. If the upper threshold of the risk coefficient is set to 0.8, an early warning will be issued when the risk coefficient exceeds the threshold and the corresponding time will be output.

[0023] Furthermore, in S2, the structural internal force of any response calculation point of the bridge structure section is calculated based on the acquired vehicle time-space distribution data at the first moment.

[0024] Calculate the mid-span positive bending moment and / or support negative bending moment and / or support shear force at the bridge structure section response calculation point, and establish influence line functions to calculate the structural internal forces;

[0025] Among them, the wheel load is decomposed into concentrated load, and the mid-span positive bending moment Ma is expressed as:

[0026] Ma=∑f(pi,xi);

[0027] P is the concentrated vehicle load distributed on the bridge deck, and x is the position of each wheel load.

[0028] Furthermore, the position coordinates of each wheel load are obtained to calculate the mid-span positive bending moment at the response calculation point of the bridge structure section monitoring point:

[0029] Determine the wheelbase according to the number of axles, establish the bridge deck coordinate system, and use the centerline of the bridge deck as the x-axis, the left lane direction as the positive direction, determine the y-coordinate of each concentrated load according to the wheelbase of each vehicle and the lane the vehicle is in, and determine the x-coordinate of each concentrated load according to the wheelbase and the position of the vehicle along the span direction. The load size is the corresponding wheel weight;

[0030] The dynamic weighing system that does not collect wheel weight information calculates the axle weight in equal parts and calculates the y coordinate of the wheel load position based on the lane position, and calculates the x coordinate of the wheel load position based on the wheelbase.

[0031] Furthermore, the bridge deck is divided into different slab units. The division of the slab units involves calculation accuracy. The smaller the slab division unit is, the higher the calculation accuracy is, but the calculation time increases. In practical applications, it can be adjusted according to the actual application to improve the calculation efficiency while ensuring that the accuracy meets the requirements.

[0032] Furthermore, the bridge deck is divided into different slab units along the transverse direction of the bridge deck, and it is determined whether the wheel load action point and the response calculation point of the bridge structure section are in the same slab unit according to the wheel load, lane, and wheelbase;

[0033] If the wheel load action point and the response calculation point of the bridge structure section are in the same plate strip unit, it is not necessary to calculate the lateral distribution coefficient when calculating the structural internal force of the bridge structure section response calculation point.

[0034] If the wheel load action point and the response calculation point of the bridge structure section are not located on the same slab, the lateral distribution coefficient and the influence line in the span direction need to be combined to calculate the structural internal force.

[0035] Furthermore, when calculating the lateral distribution effect, the distributed wheel concentrated load p of the bridge structure section and the positive bending moment Ma at position x are:

[0036] Ma=∑f(pi,xi,yi).

[0037] Further, in S4, the slope of the structural internal force-deflection curve of the cross section of the bridge structure in the second time period is determined by comparing the structural internal force-deflection fitting curve in the first time period;

[0038] If the rate of change of the slope of the bridge structure section at a certain moment in the second time period is greater than the set value, then at that moment, the bearing capacity risk coefficient must be combined to determine the abnormal bearing capacity under the vehicle distribution on the bridge deck at the corresponding moment.

[0039] Furthermore, the design value of the bearing capacity of the bridge structure section is calculated in combination with the influence line function and the design load value to obtain the design value of the mid-span bending moment bearing capacity of the bridge My (taking the mid-span positive bending moment as an example). If there is no relevant data, it can be calculated according to the design load in the specification, and the My value is calculated in combination with the influence line function and the design load value, where the uniformly distributed load is the equivalent fleet load, and the bearing capacity calculation of this part can be calculated by integrating the influence line and multiplying it by the size of the uniformly distributed load.

[0040] Furthermore, a dynamic monitoring system for the risk factor of the cross-section bearing capacity of a bridge structure is provided, the system comprising a data acquisition device and a data analysis device, the technical invention realizes the real-time monitoring of the risk factor of the bridge structure, reduces human subjective intervention, and reduces the cost of monitoring and calculation services;

[0041] The data acquisition device obtains the vehicle time-space distribution data of the bridge structure cross-section response calculation point at the first moment, the vehicle time-space distribution data at least includes the weighing time, lane, vehicle speed, number of axles, axle weight, wheelbase, and obtains the deflection of any response calculation point of the bridge structure cross-section at the first moment;

[0042] The data analysis device obtains the structural internal force of the cross-section response calculation point of the bridge structure at the first moment;

[0043] The data analysis device obtains a plurality of structural internal forces and deflections within a first time period to obtain a plurality of structural internal force-deflection scatter points, and obtains a structural internal force-deflection fitting curve and a threshold value of the fitting curve from the scatter points;

[0044] The vehicle time-space distribution data in the second time period is acquired by the data acquisition device, the structural internal force and deflection of the bridge structure cross-section response calculation point in the second time period are calculated, and a structural internal force-deflection curve is formed;

[0045] The data analysis device makes a difference between the slope value of the structural internal force-deflection fitting curve in the first time period and the slope value of the structural internal force-deflection fitting curve in the second time period;

[0046] If the difference in the slopes of the two structural internal force-deflection fitting curves is greater than a set value, it indicates that the deflection change rate of the bridge structure section accelerates as the structural internal force increases in the second time period, indicating that the bending stiffness of the bridge structure section is significantly reduced. The invention avoids artificial calculation of the deflection difference and structural internal force of the bridge structure section, and reduces the cost of monitoring and calculation services.

[0047] The data analysis device determines whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed the threshold value through the fitting curve of the structural internal force-deflection in the first time period;

[0048] If the structural internal force and deflection at that moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal;

[0049] The data analysis device calculates the bearing capacity risk coefficient Ma / My by obtaining the bridge mid-span bending moment bearing capacity design value My under the vehicle time-space distribution at the first moment and the mid-span bending moment value Ma under the vehicle load condition.

[0050] Furthermore, according to the bridge structure design calculation book, the design value of the bridge mid-span bending moment bearing capacity My (taking the mid-span positive bending moment as an example) can be input. If there is no relevant data, it can be calculated according to the standard design load, and the My value can be calculated by combining the influence line function and the design load value. The uniformly distributed load is the equivalent fleet load. The bearing capacity calculation of this part can be calculated by taking the product of the influence line integral and the uniformly distributed load size;

[0051] According to the relevant provisions of JTG D60-2015 "General Specifications for Highway Bridge and Culvert Design" on lane design loads, the design values ​​of uniformly distributed loads and concentrated loads are determined according to the span and highway grade;

[0052] The reduction factor is taken into account for multi-lane vehicle loading. According to the relevant provisions of JTG D60-2015 "General Specifications for Design of Highway Bridges and Culverts" on lane design loads, the load layout reduction factor is determined based on the number of transverse lanes and the longitudinal calculated span.

[0053] When the bearing capacity risk coefficient is greater than a set value, it is judged that the bearing capacity of the bridge structure section is abnormal at that moment, and an alarm is triggered at this moment and the time-space distribution data of vehicles in the bridge section is output;

[0054] When the risk coefficient is less than 0, it means that at this moment, the vehicle load is mainly concentrated in the adjacent span of the measuring point, and the bending moment of the monitoring point section is negative. Considering the dead weight of the bridge itself and the negative bending moment value caused by the adjacent span is generally small, it is relatively safe; the risk coefficient is equal to 0, which means that there is no vehicle passing through the calculated span bridge deck at this moment, and the internal force of the measuring point section caused by the vehicle is 0; the part with a risk coefficient greater than 0 is the focus of the algorithm output. If the upper threshold of the risk coefficient is set to 0.8, an early warning will be issued when the risk coefficient exceeds the threshold and the corresponding time will be output.

[0055] The present invention combines the structural response with the load conditions of the bridge deck to achieve real-time calculation and timely feedback of the internal force and bearing capacity risk coefficient of the bridge section. When abnormal risks occur, it can provide the time-space distribution of vehicles on the bridge deck at that time, which is helpful to further assist in completing the emergency plan processing, helping experts to timely extract the corresponding treatment methods, and timely take measures such as personnel intervention and road blocking to eliminate safety hazards in the bud. In addition, the early warning content is enriched, and the changes in the bridge bearing capacity can be further judged based on the establishment of the relationship model between the acting load and the structural response; the present invention can significantly improve the depth of mining and utilization of bridge monitoring data by realizing dynamic monitoring of the bearing capacity risk coefficient of the bridge structure section. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the accompanying drawings:

[0057] Figure 1 It is a flow chart of a method for dynamically monitoring the risk coefficient of the cross-section bearing capacity of a bridge structure according to the present invention;

[0058] Figure 2 It is a structural internal force-deflection fitting curve diagram of the method of the present invention;

[0059] Figure 3 It is a second flow chart of a method for dynamically monitoring a risk factor of a bridge structure cross-section bearing capacity according to the present invention;

[0060] Figure 4 It is a schematic diagram of a dynamic monitoring method of a bridge structure cross-section bearing capacity risk coefficient of the present invention, which calculates the mid-span positive bending moment Ma by considering the lateral distribution coefficient and the longitudinal influence line;

[0061] Figure 5 It is a lateral distribution coefficient curve diagram of a dynamic monitoring method of a bridge structure cross-section bearing capacity risk coefficient of the present invention;

[0062] Figure 6 A distribution curve of the mid-span bending moment influence line of a dynamic monitoring method for a bridge structure cross-section bearing capacity risk factor of the present invention, taking a two-span continuous beam as an example;

[0063] Figure 7 It is a system diagram of a dynamic monitoring method of a bridge structure cross-section bearing capacity risk coefficient of the present invention;

[0064] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0066] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0067] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] Example 1

[0069] like Figure 1 As shown, a dynamic monitoring method for a bridge structure section bearing capacity risk coefficient according to the present invention comprises the following steps:

[0070] S 1. Obtain the vehicle temporal and spatial distribution data at the first moment, the vehicle temporal and spatial distribution data at least including weighing time, lane, vehicle speed, number of axles, axle weight, wheelbase,

[0071] According to the monitoring system, the deflection of any response calculation point of the bridge structure section at the first moment is obtained in real time;

[0072] Take vehicle A in the first moment's vehicle spatiotemporal distribution data as an example:

[0073] For example, take a 5-axle vehicle A in the vehicle spatiotemporal distribution data at 2023-03-13 00:03:54.000 as an example. At this time, vehicle A is in lane 2 and the speed is 79km / h. The left wheel load 1wi and right wheel load rwi values ​​and wheelbase di of vehicle A at this time are shown in the following table respectively;

[0074]

[0075] Obtain the deflection of any response calculation point of the bridge structure section at the first moment;

[0076] In this embodiment, the response calculation point positions of the structural cross-section of the bridge are arranged according to the design specifications of different types of bridges; taking a continuous beam bridge as an example: the main working conditions of the continuous beam bridge are (1) the maximum negative bending moment condition at the main span support position, (2) the maximum positive bending moment condition at the mid-span section of the main span, and (3) the maximum positive bending moment condition of the side span main beam; the additional working condition is: the maximum shear force condition of the main beam near the main span (middle) support, then the test sections of the continuous beam bridge are the main span (middle) support section, the main span maximum bending moment section, and the side span maximum bending moment section.

[0077] In this embodiment, S2, using the time-space distribution data of vehicles at the first moment, respectively calculating the structural internal force of the same response calculation point of the bridge structure section at the first moment and the deflection at the first moment;

[0078] Calculate the mid-span positive bending moment and / or support negative bending moment and / or support shear force at the bridge structure section response calculation point, and establish influence line functions to calculate the structural internal forces;

[0079] In this embodiment, the mid-span positive bending moment and / or the support negative bending moment and / or the support shear force at the calculated response calculation point need to be determined according to the test conditions of different bridge types;

[0080] Taking the continuous beam bridge as an example: the main working conditions of the continuous beam bridge are (1) the maximum negative bending moment condition at the main span support, (2) the maximum positive bending moment condition at the mid-span section of the main span, and (3) the maximum positive bending moment condition of the side span main beam; the additional working condition is: the maximum shear force condition of the main beam near the main span (middle) support. The test sections of the continuous beam bridge are the main span (middle) support section, the main span maximum bending moment section, and the side span maximum bending moment section.

[0081] Among them, to calculate the mid-span positive bending moment, it is necessary to decompose the wheel load into concentrated loads. The expression of the mid-span positive bending moment Ma is:

[0082] Ma=∑f(pi,xi);

[0083] P is the concentrated vehicle load distributed on the bridge deck, and x is the position of each wheel load.

[0084] In this embodiment, the position coordinates of each wheel load are obtained to calculate the mid-span positive bending moment at the bridge structure section response calculation point:

[0085] Determine the wheelbase according to the number of axles, establish the bridge deck coordinate system, and use the centerline of the bridge deck as the x-axis, the left lane direction as the positive direction, determine the y-coordinate of each concentrated load according to the wheelbase of each vehicle and the lane the vehicle is in, and determine the x-coordinate of each concentrated load according to the wheelbase and the position of the vehicle along the span direction. The load size is the corresponding wheel weight;

[0086] The dynamic weighing system that does not collect wheel weight information calculates the axle weight in equal parts and calculates the y coordinate of the wheel load position based on the lane position, and calculates the x coordinate of the wheel load position based on the wheelbase.

[0087] In this embodiment, according to the time-space distribution table of the vehicle in the bridge structure section at the first moment, the axle weight and wheelbase information of the vehicle are supplemented by the dynamic weighing system, and the vehicle load is decomposed to the bridge deck according to the wheel weight pi;

[0088] Attached Figure 6 It is a distribution curve of the mid-span bending moment influence line taking a two-span continuous beam as an example. The horizontal axis is the distance x / m between the load action point and the initial point of the main span, and the vertical axis is the bending moment Nm. According to the wheel weight information and the position, the mid-span bending moment value caused by the wheel weight is calculated, and the mid-span bending moment values ​​calculated from the concentrated load points obtained by decomposing all vehicles at this moment are superimposed to obtain the mid-span bending moment value Ma under the corresponding bridge deck vehicle load condition at this moment.

[0089] In this embodiment, the structural cross-section of the bridge deck can be divided into different plate-strip units. The division of the plate-strip units involves calculation accuracy. The smaller the plate-strip division unit is, the higher the calculation accuracy is, but the calculation time is increased. In actual applications, it can be adjusted according to the actual application to improve the calculation efficiency while ensuring that the accuracy meets the requirements.

[0090] In this embodiment, the bridge deck is divided into different slab units along the transverse direction of the bridge deck, and it is determined whether the wheel load action point and the response calculation point of the bridge structure section are in the same slab unit according to the wheel load, lane, and wheelbase;

[0091] If the wheel load action point and the response calculation point of the bridge structure section are in the same plate strip unit, it is not necessary to calculate the lateral distribution coefficient when calculating the structural internal force of the bridge structure section response calculation point.

[0092] If the wheel load action point and the response calculation point of the bridge structure section are not located on the same slab, the lateral distribution coefficient and the influence line in the span direction need to be combined to calculate the structural internal force.

[0093] In this embodiment, the lateral load distribution coefficient is not calculated. It is generally applied to two-lane bridges with integral box beams and T-beam sections. For bridges with multiple main beam sections, generally with more than two lanes, it is necessary to further consider the lateral distribution effect of vehicle loads. For bridges where the action point and the response calculation point are not in the same slab (the bridge deck is divided into different slab units along the transverse direction of the bridge deck), its lateral distribution coefficient needs to be calculated, combined with the span direction influence line combination calculation. At this time, the expression of the concentrated force p of the bridge deck distribution vehicle and the positive bending moment Ma of the force at position x should be: Ma = ∑f(pi, xi, yi), and its calculation diagram is shown in the attached figure. Figure 5 :

[0094] See attached for details Figure 4 In the process, the vehicle is decomposed into concentrated loads according to the wheels, and the structural internal forces caused by each concentrated load at the response calculation point are calculated. First, the concentrated load is divided according to the lateral distribution coefficient curve (see the attached Figure 5 ) The load is equivalent to the slab where the response calculation point is located, and then the structural internal force caused by the load is calculated through the structural internal force influence line in the span direction. Similarly, all concentrated loads on the bridge deck are equivalently calculated and added together to calculate the structural internal force response value of the response calculation point under the vehicle load distribution on the bridge deck at that moment.

[0095] In this embodiment, S3, see the attached Figure 2 , taking multiple moments in the first period of time to obtain multiple structural internal force-deflection scatter points, and obtaining the structural internal force-deflection fitting curve and the threshold of the fitting curve from the scatter points;

[0096] S4, taking the time-space distribution data of vehicles in the second time period, calculating the structural internal force and deflection of the same response calculation point of the bridge structure section in the second time period and obtaining a structural internal force-deflection curve;

[0097] Subtract the slope value of the structural internal force-deflection fitting curve in the first time period from the slope value of the structural internal force-deflection fitting curve in the second time period;

[0098] If the difference in the slopes of the two structural internal force-deflection fitting curves is greater than the set value, it is judged that the bearing capacity of the bridge structure section in the second time period is abnormal and the vehicle spatiotemporal distribution data at the abnormal moment is output in real time. This indicates that the bending stiffness of the bridge structure section is significantly reduced, and it is necessary to check whether the sensor is abnormal or whether there are obvious cracks at the bottom of the main beam. At the same time, it is necessary to combine the risk coefficient output by this algorithm to check whether there is overload in the vehicle distribution on the bridge deck at the corresponding moment.

[0099] S5. judging whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed a threshold value through a fitting curve of the structural internal force-deflection in the first time period;

[0100] If the structural internal force and deflection at this moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at this moment is abnormal; in this embodiment, the upper and lower thresholds of the curve indicate the reasonable deflection range under the corresponding structural internal force, considering factors such as sensor equipment error and calculation error;

[0101] See attached for details Figure 2 When the structural internal force is 4000, the reasonable deflection monitoring value should be within [-1, 2.5]. If the length of this interval, that is, the sigma value, increases significantly, it indicates that the discreteness of the scattered data increases. It is necessary to verify whether there is obvious data distortion in the sensor data, or there is an obvious deviation between the sensor recording acquisition time and the dynamic weighing acquisition time.

[0102] The present invention can help to timely check whether there is obvious data distortion in sensor data, or obvious deviation between sensor recording acquisition time and dynamic weighing acquisition time, or warn of the risk of bearing capacity limit in the cross section of the bridge structure by issuing a warning in time when the deflection corresponding to the internal force of the structure at a certain moment exceeds the threshold range of the fitting curve, so as to help timely assist personnel to intervene in time and eliminate safety hazards in the bud.

[0103] In this embodiment, the bearing capacity risk coefficient Ma / My is calculated by obtaining the design value My of the mid-span bending moment bearing capacity of the bridge under the time-space distribution of vehicles at the first moment and the mid-span bending moment value Ma under the vehicle load condition.

[0104] According to the bridge structure design calculation book, the design value of the bridge mid-span bending moment bearing capacity My (taking the mid-span positive bending moment as an example) can be input. If there is no relevant data, it can be calculated according to the standard design load, and the My value can be calculated by combining the influence line function and the design load value. The uniformly distributed load is the equivalent fleet load. The bearing capacity calculation of this part can be calculated by taking the product of the influence line integral and the uniformly distributed load size;

[0105] According to the relevant provisions of JTG D60-2015 "General Specifications for Highway Bridge and Culvert Design" on lane design loads, the design values ​​of uniformly distributed loads and concentrated loads are determined according to the span and highway grade;

[0106] The reduction factor is taken into account for multi-lane vehicle loading. According to the relevant provisions of JTG D60-2015 "General Specifications for Design of Highway Bridges and Culverts" on lane design loads, the load layout reduction factor is determined based on the number of transverse lanes and the longitudinal calculated span.

[0107] When the bearing capacity risk coefficient is greater than a set value, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal and an alarm is issued. When the bearing capacity risk coefficient exceeds the standard set value, a warning is issued and the corresponding moment warning is output. The vehicle time-space distribution data at the warning moment is output. This technical invention can feedback the time-space distribution information of bridge deck vehicles when the structural bearing capacity limit warning appears, which has positive significance for assisting traffic control decision-making and basic research. The present invention realizes the real-time monitoring of the bearing capacity risk coefficient of the bridge beam structure section, reduces human subjective intervention, and reduces the monitoring and calculation service costs.

[0108] In this embodiment, a monitoring system for the risk coefficient of the cross-section bearing capacity of a bridge structure is included, wherein a data acquisition device obtains the time-space distribution data of vehicles at a response calculation point of the cross-section of the bridge structure at a first moment, wherein the time-space distribution data of vehicles at least includes weighing time, lane, vehicle speed, number of axles, axle weight, and wheelbase, and obtains the deflection of any response calculation point of the cross-section of the bridge structure at the first moment;

[0109] The data analysis device uses the time-space distribution data of the vehicles to respectively calculate the structural internal force of the same response calculation point of the bridge structure section and the deflection at the first moment;

[0110] The data analysis device establishes a structural internal force-deflection curve through the structural internal force and deflection in the first time period, obtains a plurality of structural internal force-deflection scatter points, and obtains a structural internal force-deflection fitting curve and a threshold value of the fitting curve from the scatter points;

[0111] The vehicle time-space distribution data in the second time period is acquired by the data acquisition device, the structural internal force and deflection of the bridge structure cross-section response calculation point in the second time period are calculated, and a structural internal force-deflection curve is formed;

[0112] The data analysis device makes a difference between the slope value of the structural internal force-deflection fitting curve in the first time period and the slope value of the structural internal force-deflection fitting curve in the second time period;

[0113] If the difference between the slopes of the two structural internal force-deflection fitting curves is greater than the set value, it means that the deflection change rate of the bridge structure section accelerates with the increase of the structural internal force in the second time period, indicating that the bending stiffness of the bridge structure section is significantly reduced;

[0114] The data analysis device determines whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed the threshold value through the fitting curve of the structural internal force-deflection in the first time period;

[0115] If the structural internal force and deflection at that moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal;

[0116] The data analysis device calculates the bearing capacity risk coefficient Ma / My by obtaining the bridge mid-span bending moment bearing capacity design value My under the vehicle time-space distribution at the first moment and the mid-span bending moment value Ma under the vehicle load condition.

[0117] When the bearing capacity risk coefficient is greater than a set value, it is judged that the bearing capacity of the bridge structure section is abnormal at that moment, and an alarm is issued and the vehicle time-space distribution data at that moment is output.

[0118] The invented method can be implemented in Python, and its input and output parameter requirements and real data example output results are as follows:

[0119] Request Parameters

[0120] Subtype Description 1) Request Parameters

[0121]

[0122]

[0123] Subtype Description Vehicle

[0124]

[0125]

[0126] response

[0127]

[0128] Influence

[0129]

[0130]

[0131] 2) Return parameter

[0132]

[0133]

[0134] 3) Output result application diagram

[0135] The algorithm is called once a day. In the request parameters, s_start, s_end, influence_line_x, influence_line_y, and bear_moment are the bridge parameter configuration files. The above parameters remain unchanged each time the sensors on the bridge are called. It is recommended that tinval be 2, and beam_type is determined according to the bridge section type; lane_winth = None, sensor_local = None, influence_line_h = None, and coef_limit = None are optional input items. When beam_type is 1, the above optional input items are required. The algorithm targets different main beam dynamic deflection sensors and different calculation time ranges, and inputs the vehicle load data samp1e_vehicle and deflection data sample_deflection within the corresponding time range. It is recommended to use the cutoff call time and one day of historical data for calculation to output the section internal force-deflection relationship model and the load risk coefficient per tinval seconds within the calculation time range. In addition, if the risk factor threshold coef_limit is set, the calculation time corresponding to the time when the risk factor exceeds the threshold can be output additionally, which can be used to extract the vehicle load distribution of the bridge deck at that moment for further analysis.

[0136] Example 2

[0137] In this embodiment, a monitoring system for a bridge structure cross-section bearing capacity risk factor includes a data acquisition device and a data analysis device;

[0138] The data acquisition device obtains the vehicle time-space distribution data of the bridge structure cross-section response calculation point at the first moment, and the vehicle time-space distribution data at least includes the weighing time, lane, vehicle speed, number of axles, axle weight, and wheelbase, and obtains the deflection of any response calculation point of the bridge structure cross-section at the first moment;

[0139] The data analysis device obtains the structural internal force of the cross-section response calculation point of the bridge structure at the first moment;

[0140] The data analysis device obtains a plurality of structural internal forces and deflections within a first period of time to obtain a plurality of structural internal force-deflection scatter points, and obtains a structural internal force-deflection fitting curve and a threshold value of the fitting curve from the scatter points;

[0141] The vehicle time-space distribution data in the second time period is acquired by the data acquisition device, the structural internal force and deflection of the bridge structure cross-section response calculation point in the second time period are calculated, and a structural internal force-deflection curve is formed;

[0142] The data analysis device makes a difference between the slope value of the structural internal force-deflection fitting curve in the first time period and the slope value of the structural internal force-deflection fitting curve in the second time period;

[0143] If the difference between the slopes of the two structural internal force-deflection fitting curves is greater than the set value, it means that the deflection change rate of the bridge structure section accelerates with the increase of the structural internal force in the second time period, indicating that the bending stiffness of the bridge structure section is significantly reduced;

[0144] The data analysis device determines whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed the threshold value through the fitting curve of the structural internal force-deflection in the first time period;

[0145] If the structural internal force and deflection at that moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal, and an alarm is sounded at that moment and the vehicle time-space distribution data at the alarm moment is output;

[0146] The data analysis device calculates the bearing capacity risk coefficient Ma / My by obtaining the bridge mid-span bending moment bearing capacity design value My under the vehicle time-space distribution at the first moment and the mid-span bending moment value Ma under the vehicle load condition.

[0147] When the bearing capacity risk coefficient is greater than a set value, it is judged that the bearing capacity of the bridge structure section is abnormal at that moment, an alarm is issued, and the vehicle time-space distribution data at the alarm moment is output.

[0148] The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content suggested above without departing from the scope of the technical solution of the present invention. The implementation scheme in the above embodiment can also be further combined or replaced. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the solution of the present invention.

Claims

1. A dynamic monitoring method for the risk factor of the cross-section bearing capacity of a bridge structure, characterized in that: The following steps are included: S1. Obtaining the spatiotemporal distribution data of vehicles at the first moment, the spatiotemporal distribution data of vehicles at least including weighing time, lane, vehicle speed, number of axles, axle weight, wheelbase, and obtaining the deflection of any response calculation point of the bridge structure section at the first moment; S2, using the time-space distribution data of the vehicles to respectively calculate the structural internal force of the same response calculation point of the bridge structure section and the deflection at the first moment; S3, taking multiple moments within the first period of time to obtain multiple structural internal force-deflection scatter points, and obtaining a structural internal force-deflection fitting curve and a threshold value of the fitting curve from the scatter points; S4, obtaining the time-space distribution data of vehicles in the second time period, calculating the structural internal force and deflection of the same response calculation point of the bridge structure section in the second time period and obtaining a structural internal force-deflection curve; Subtract the slope value of the structural internal force-deflection fitting curve in the first time period from the slope value of the structural internal force-deflection fitting curve in the second time period; If the difference in the slopes of the two structural internal force-deflection fitting curves is greater than a set value, it is determined that the bearing capacity of the bridge structure section in the second time period is abnormal, and the vehicle spatiotemporal distribution data at the abnormal moment is output in real time.

2. A dynamic monitoring method for the risk coefficient of the cross-section bearing capacity of a bridge structure according to claim 1, characterized in that: A dynamic monitoring method for a bridge structure section bearing capacity risk factor also includes: S5. judging whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed a threshold value through a fitting curve of the structural internal force-deflection in the first time period; If the structural internal force and deflection at that moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal.

3. A dynamic monitoring method for the risk coefficient of the cross-section bearing capacity of a bridge structure according to claim 1 or 2, characterized in that: By obtaining the design value My of the mid-span bending moment bearing capacity of the bridge under the time-space distribution of vehicles at the first moment and the mid-span bending moment value Ma under the vehicle load condition, the bearing capacity risk coefficient Ma / My is calculated. When the bearing capacity risk coefficient is greater than a set value, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal and an alarm is issued.

4. The method for dynamic monitoring of the risk factor of the cross-section bearing capacity of a bridge structure according to claim 1, characterized in that: In S2, the structural internal force of any response calculation point of the bridge structure section is calculated based on the vehicle time-space distribution data obtained at the first moment. Calculate the mid-span positive bending moment and / or support negative bending moment and / or support shear force at the bridge structure section response calculation point, and establish influence line functions to calculate the structural internal forces; Among them, the wheel load is decomposed into concentrated load, and the mid-span positive bending moment Ma is expressed as: Ma=∑f(pi,xi); P is the concentrated vehicle load distributed on the bridge deck, and x is the position of the Y load on each wheel.

5. A dynamic monitoring method for the risk factor of the cross-section bearing capacity of a bridge structure as claimed in claim 4, characterized in that: The position coordinates of each wheel load are obtained to calculate the mid-span positive bending moment at the response calculation point of the bridge structure section monitoring point: The wheelbase is determined according to the number of axles, and the bridge deck coordinate system is established to calculate the centerline of the bridge deck as the x-axis and the left lane direction as the positive direction. The y-coordinate of each concentrated load is determined according to the wheelbase of each vehicle and the lane the vehicle is in. The x-coordinate of each concentrated load is determined according to the wheelbase and the position of the vehicle along the span direction. The load size is the corresponding wheel weight.

6. A method for dynamically monitoring the risk factor of the cross-section bearing capacity of a bridge structure according to claim 1 or 5, characterized in that: Divide the bridge deck into different slab units along the transverse direction of the bridge deck, and determine whether the wheel load action point and the response calculation point of the bridge structure section are in the same slab unit according to the wheel load, lane, and wheelbase; If the wheel load action point and the response calculation point of the bridge structure section are in the same plate strip unit, it is not necessary to calculate the lateral distribution coefficient when calculating the structural internal force of the bridge structure section response calculation point. If the wheel load action point and the response calculation point of the bridge structure section are not located on the same slab, the lateral distribution coefficient and the influence line in the span direction need to be combined to calculate the structural internal force.

7. A dynamic monitoring method for the risk factor of the cross-section bearing capacity of a bridge structure as claimed in claim 6, characterized in that: When calculating the lateral distribution coefficient, the distribution of the wheel concentrated load p and the positive bending moment Ma at position x in the bridge structure section is: Ma=∑f(pi,xi,yi).

8. A method for dynamically monitoring the risk factor of the cross-section bearing capacity of a bridge structure according to any one of claims 1 to 3, characterized in that: In S4, the slope of the structural internal force-deflection curve of the bridge structure section in the second time period is determined by comparing the structural internal force-deflection fitting curve in the first time period; If the rate of change of the slope of the bridge structure section at a certain moment in the second time period is greater than the set value, then at that moment, the bearing capacity risk coefficient must be combined to determine the abnormal bearing capacity under the vehicle distribution on the bridge deck at the corresponding moment.

9. A method for dynamically monitoring the risk factor of the cross-section bearing capacity of a bridge structure as claimed in claim 3, characterized in that: The design value of the bearing capacity of the bridge structure section is calculated by combining the influence line function and the design load value to obtain the design value of the mid-span bending moment bearing capacity of the bridge My, where the uniformly distributed load is the equivalent fleet load, and this part of the bearing capacity is calculated by integrating the influence line and multiplying it by the uniformly distributed load.

10. A monitoring system for a bridge structure cross-section bearing capacity risk coefficient, using a dynamic monitoring method for a bridge structure cross-section bearing capacity risk coefficient as described in any one of claims 1 to 9, characterized in that: The data acquisition device obtains the vehicle time-space distribution data of the bridge structure cross-section response calculation point at the first moment, the vehicle time-space distribution data at least includes the weighing time, lane, vehicle speed, number of axles, axle weight, wheelbase, and obtains the deflection of any response calculation point of the bridge structure cross-section at the first moment; The data analysis device uses the time-space distribution data of the vehicles to respectively calculate the structural internal force of the same response calculation point of the bridge structure section and the deflection at the first moment; The data analysis device establishes a structural internal force-deflection curve through the structural internal force and deflection in the first time period, obtains a plurality of structural internal force-deflection scatter points, and obtains a structural internal force-deflection fitting curve and a threshold value of the fitting curve from the scatter points; The vehicle time-space distribution data in the second time period is acquired by the data acquisition device, the structural internal force and deflection of the bridge structure cross-section response calculation point in the second time period are calculated, and a structural internal force-deflection curve is formed; The data analysis device makes a difference between the slope value of the structural internal force-deflection fitting curve in the first time period and the slope value of the structural internal force-deflection fitting curve in the second time period; If the difference between the slopes of the two structural internal force-deflection fitting curves is greater than the set value, it means that the deflection change rate of the bridge structure section accelerates with the increase of the structural internal force in the second time period, indicating that the bending stiffness of the bridge structure section is significantly reduced; The data analysis device determines whether the structural internal force and deflection of the cross section of the bridge structure at any time in the second time period exceed the threshold value through the fitting curve of the structural internal force-deflection in the first time period; If the structural internal force and deflection at that moment exceed the threshold of the fitting curve, it is judged that the bearing capacity of the bridge structure section at that moment is abnormal; The data analysis device calculates the bearing capacity risk coefficient Ma / My by obtaining the bridge mid-span bending moment bearing capacity design value My under the vehicle time-space distribution at the first moment and the mid-span bending moment value Ma under the vehicle load condition. When the bearing capacity risk coefficient is greater than a set value, it is judged that the bearing capacity of the bridge structure section is abnormal at that moment, and an alarm is issued and the vehicle time-space distribution data at that moment is output.

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