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142 results about "Influence line" patented technology

In engineering, an influence line graphs the variation of a function (such as the shear felt in a structure member) at a specific point on a beam or truss caused by a unit load placed at any point along the structure. Some of the common functions studied with influence lines include reactions (the forces that the structure’s supports must apply in order for the structure to remain static), shear, moment, and deflection (Deformation) . Influence lines are important in designing beams and trusses used in bridges, crane rails, conveyor belts, floor girders, and other structures where loads will move along their span. The influence lines show where a load will create the maximum effect for any of the functions studied.

Quick load test method for bridge carrying capacity

The invention relates to a quick load test method for bridge carrying capacity, and aims to provide a quick and accurate bridge carrying capacity evaluating method. The method comprises the following steps: performing a bridge quasi-static load test; establishing an initial finite element model; correcting the model by a control measuring point strain influence line obtained through actual measurement of the quasi-static load test; respectively distributing loads on the model before and after the correction according to the load test requirement, and calculating to obtain control measuring point flexivity values f before the correction and f after the correction; and defining that eta'=1.1*f after the correction / f before the correction, obtaining a check-calculation coefficient Z2 of a structure according to the efficiency coefficient eta', and performing check calculation on the structure through Z2.
Owner:JSTI GRP CO LTD

Bridge local damage identification method based on influence line under structure health monitoring system

A bridge local damage identification method based on an influence line under a structure health monitoring system relates to the field of engineering structure health monitoring. The method comprises the following steps: (1) fast identification of a bridge influence line; (2) construction of influence line damage indexes; and (3) damage identification based on fusion of multi-sensor information. A bridge influence line is identified based on moving vehicles and bridge response monitored in real time by a bridge health monitoring system, the change of the influence line can be captured in a timelier and quicker way, and structure abnormality can be found early. Based on the fact that the damage indexes of the influence line are more sensitive to local damage of long-span bridges and less sensitive to the change in environmental factors, the method is more applicable to detection of local damage of long-span bridges in an operating environment. By combining the multi-sensor information fusion theory and the influence line damage indexes, the anti-noise-interference and damage locating abilities of the damage identification method are improved greatly, and the credibility of damage decision is improved.
Owner:XIAMEN UNIV

Rapid bridge detection method based on influence lines

ActiveCN107132011AImprove measurement and calculation accuracyQuick checkInformaticsSpecial data processing applicationsInfluence lineSpecific function
The invention relates to a rapid bridge detection method, which belongs to the technical field of civil engineering application. Firstly, a loading test vehicle with known axle load and wheelbase is adopted for loading to measure response of a test point; then, a method of adopting a specific function (piecewise polynomial and sine wave stacking) to fit the dynamic response of the test point is adopted to extract influence line information of the bridge; a tire-pavement stress distribution emprical formula is introduced to build a tire-pavement contact force trapezoid distribution model; in combination of the actual influence line information and the vehicle tire-pavement contact force distribution model, a linear superposition method is adopted to reconstruct bridge test point response information under different vehicle load combination effects, and thus, rapid bridge detection based on the influence lines is realized. Based on few driving tests on a single vehicle, the actual influence line information can be acquired rapidly and accurately, the bridge response information under different static load combination working conditions is reconstructed, rapid bridge detection is achieved, and the defects that the existing bridge detection method is long in consumed time, high in economic cost and long in traffic block time can be solved.
Owner:CENT SOUTH UNIV

Bridge fast load experimental test method

The invention provides a bridge fast load experimental test method comprising the following steps that a bridge finite element calculation model is established; a displacement measuring point is arranged at the key part of a test span; automobiles are slowly driven along the bridge deck, and the displacement influence line of the bridge is acquired; the actually measured curve of the bridge displacement influence line is drawn; the actually measured displacement value of high credibility is selected according to the actual result of the displacement influence test data; a multi-condition loading model is established according to the selected actually measured displacement value and the vehicle load corresponding position so as to perform finite element analysis and calculation; a displacement residual error expression is established, and a target function is formed to perform finite element model correction; and the deflection and the strain under the load test condition are calculated by adopting the corrected finite element model, the corrected model calculation value acts as the actually measured value and the uncorrected model calculation value acts as the theoretical value to calculate the verification coefficient and bridge carrying capacity evaluation is performed according to the specifications of bridge carrying capacity evaluation.
Owner:山西省交通建设工程质量检测中心(有限公司)

Bridge influence line dynamic test method

The invention relates to a bridge influence line dynamic test method, and belongs to the technical field of civil engineering application. A mixed function f(x)=f1(x)+f2(x) formed by a polynomial f1(x) and amplitude tunable sine wave f2(x) is established firstly, then response of a test point is tested by experiments, and dynamic response {re} of the test point under the effect of unit moving load is obtained by an anti-inference method; and finally least square fitting is performed on the obtained dynamic response {re} of the bridge crossing test point under the unit moving load by using the mixed function f(x), and a corresponding bridge influence line is separated and extracted. Difficulty of distortion of the obtained influence line in the aspect of amplitude or shape and the like in existing bridge influence line dynamic test methods can be solved by the method, and the bridge influence line which is high in precision and can further reflect reality is obtained.
Owner:CENT SOUTH UNIV

Bridge influence line identification method and system

The invention discloses a bridge influence line identification method and system. The method comprises the following steps: (1) a mathematic model for influence line identification is built; (2) influence line identification is performed based on a B spline curve. According to the method, actual measurement information of moving vehicles and bridge response caused by the moving vehicles is used, regularization theories and a B spline curve construction method are adopted, a problem that influence line identification is excessively sensitive to errors such as measurement noise and the like canbe effectively alleviated; the method is high in identification precision and great in potential for subsequent projection application; compared with a conventional method, the method can be used forinfluence line identification directly based on actually measured dynamic bridge response data, the method is simple and fast in operation, the method can be used for real time monitoring of key indexes of a bridge and can help effectively suppress influence line fluctuation which is not in line with physical meaning, and influence line identification precision can be improved.
Owner:XIAMEN UNIV

Frequency domain analysis method of bridge fatigue life on the basis of dynamic weighing system

The invention relates to a frequency domain analysis method of bridge fatigue life on the basis of a dynamic weighing system. The frequency domain analysis method comprises the following steps: collecting data including the vehicle weight, the vehicle speed and the axle distance of each vehicle which passes through a bridge; calculating the collected data, and carrying out curve fitting; according to a fitting probability density curve, establishing a cellular automata simulation model of the vehicle, and generating a random traffic flow; simulating load time history under different vehicle flow density conditions, and loading the load time history to a bridge influence line to obtain stress time history data; carrying out FFT (Fast Fourier Transform) on the stress time history, obtaining PSD (Power Spectral Density), and calculating relevant parameters; using a Dirlik method to establish an experience form of a PDF (Probability Distribution Function); and calculating residual service life. Calculation time is greatly shortened.
Owner:TIANJIN UNIV

Manufacture method for prestress steel-concrete combined bridge

The invention relates to a manufacture method for a prestress steel-concrete combined bridge, comprising the steps of: computing a position most disadvantageous to live load and the size of the live load at the position according to a positive bending moment influence line of fulcrum of a steel girder; casting positive bending moment area concrete in the positive bending moment area of the steel girder; placing pre-compression counterweight on the positive bending moment area concrete, wherein position and size of the pre-compression counterweight are same as those of the live load at the most disadvantageous position; casting steel fiber expansion concrete at the negative bending moment area; and detaching the pre-compression counterweight after the steel fiber expansion concrete reacheshardening strength. A connecting piece at the top of the steel girder comprises a rigid combination connecting piece, a flexible combination connecting piece or a non-combination connecting piece, and an elastic combination connecting piece. According to the manufacture method for the prestress steel-concrete combined bridge, disclosed by the invention, the pre-compression counterweight is quantitatively and accurately distributed on the positive bending moment area concrete according to the most disadvantageous position and the size of the live load, the positive bending moment is obtained at the fulcrum; pressure stress is obtained by the concrete on the steel girder, so that the storage of the bridge can counteract the pre-load of the live load.
Owner:SHENZHEN UNIV +1

Bridge bearing capacity evaluation method based on moving load test

ActiveCN110377943AReflect carrying capacityGood description of the change in carrying capacityGeometric CADDesign optimisation/simulationInfluence lineData information
The invention relates to a bridge bearing capacity evaluation method, and belongs to the technical field of civil engineering application. The method comprises the following steps: firstly, measuringthe dynamic response of a bridge under the action of a moving load through a field test; calculating and extracting an actual influence line of the bridge by adopting a piecewise polynomial function model and a cyclic fitting thought; constructing an influence line evaluation index based on the actual influence line and the theoretical influence line of the bridge; and evaluating the bearing capacity of the bridge by means of the constructed indexes instead of a traditional bridge load test static calibration coefficient. According to the method, the problem of bridge bearing capacity evaluation is solved; a load test method has the defects that the development cost is high, traffic needs to be influenced or interrupted, and time and labor are consumed. The bridge bearing capacity evaluation test process based on the moving load test is simple, the amount of acquired recorded data information is large, and the bridge bearing capacity evaluation test method has great significance in achieving rapidity and economization of bridge bearing capacity evaluation; in addition, the possibility of bridge damage caused by large-scale loading in a static load test can be avoided.
Owner:CENT SOUTH UNIV

Bridge damage detection method

The invention provides a bridge damage detection method. Through field experiments, the bridge bottom testing point flexibility response due to bridge passing by a vehicle can be obtained through test; then, the vehicle axle information is combined; a multi-section function model is introduced; a flexibility influence line (the influence line includes relevant information of the bridge damage) ofthe test point through mathematical inversion; on the basis of the test point position, the base function-non-damaged base function capable of reflecting non-damaged state is built; the damage index is built by combining the flexibility influence line and the non-damaged base function; the damage positioning can be performed through the damage index curve local peak value point. The base functioncapable of describing the damage degree is built according to the recognized damage position information, and is called as the damage base function; the bridge practical flexibility influence line andthe non-damaged base function and the damage base function are built in a combined way; through the least square fitting collation, the effective recognition on the damage degree is realized. The problem of non-damaged state information requirement of the exiting bridge damage detection method is solved. The test is simple; the test data information quantity is great; high practical significanceand values are realized.
Owner:CENT SOUTH UNIV

Lightning stroke link risk judging method based on thunder and lightning information

InactiveCN102646150AAffects the degree of risk of lightning trippingSpecial data processing applicationsInfluence lineLightning strokes
The invention relates to a lightning stroke link risk judging method based on thunder and lightning information, which comprises the following steps of: 1, establishing a thunder and lightning statistic buffer zone, and establishing five buffer zones in parallel with a line; 2, counting a ground lightning density of each buffer zone, and counting and sequencing by sections; and 3, forecasting a data flow. According to the lightning stroke link risk judging method based on the thunder and lightning information, on the basis of near real-time data provided by a thunder and lightning locating system, calculation and analysis are carried out according to the condition of ground lightning around the line, then grading is carried out according to the distance between the ground lightning zone and the line and the ground lightning density, and the lightning stroke link risk degree of the influenced line can be given according to the required prediction time.
Owner:EAST CHINA ELECTRIC POWER TEST & RES INST

Method for identifying damage and quantitatively analyzing damage degree of main girder of bridge erecting machine

ActiveCN108846197AUnable to resolve damageFound when solvingGeometric CADDesign optimisation/simulationInfluence lineEngineering
The invention relates to a method for identifying damage and quantitatively analyzing damage degree of a main girder of a bridge erecting machine. Based on the present situation that the main girder support changes with time in the operation process of the bridge erecting machine, a main girder structure type judging module MI, a damage identifying and analyzing module MII and a damage quantitatively analyzing module MIII are established. The damage identifying and analyzing module includes: (1) a deflection test system is installed; (2) deflection detection data is collected; (3) the detection data is processed to obtain a deflection influence line f1 (x); (4) the deflection influence line is processed to obtain a deflection rate curve f1 "(x); (5) whether mutation exists is judged; (6) the locations and quantity of injuries are judged. The damage quantitatively analyzing module includes: (1) a numerical simulation model is established; (2) n kinds of damage conditions are constructed, and m damage degrees are constructed for each kind of damage condition. (3) the deflection values of different damage degrees are obtained, and the relationship curve of deflection rate and damage degree is defined. (4) the relationship of deflection rate and damage degree of the main girder of the bridge erecting machine is obtained. The invention solves the problem that the structural damage of the main girder of the bridge erecting machine cannot be found in time, and the bridge erecting machine is easy to cause a serious safety accident.
Owner:SHIJIAZHUANG TIEDAO UNIV

Calculation method of small and medium-span continuous bridge hogging moment impact coefficient

ActiveCN105404718APerfect design theoryPerfect calculation methodSpecial data processing applicationsInfluence lineEngineering
The invention discloses a calculation method of a small and medium-span continuous bridge hogging moment impact coefficient. A small and medium-span continuous bridge is taken as an object, the characteristics, including the structural style, the geometrical morphology, the supporting situation, the quality, the rigidity and the like, of the bridge as well as the influence factors of the impact coefficients, including the amount, the axle number, the axle weight, the axle interval, the driving speed and the like of a vehicle are comprehensively considered, a method of combining theoretical analysis with numerical simulation is adopted to solve a computational formula problem of the regression fitting of the continuous bridge hogging moment impact coefficient according to an interrelation between the impact coefficient and an internal force influence line, the vehicle-mounted dynamic behaviors and mechanisms of the continuous bridge are disclosed, a bridge design theory and a bridge calculation method can be enriched, references are provided for bridge dynamics assessment, and the calculation method is accelerated to be widely applied and developed.
Owner:CHANGAN UNIV +1

Line loss multi-source diagnosis method and system based on correlation analysis

ActiveCN107832855AImprove management levelImprove line loss management efficiencyResourcesInfluence lineCorrelation analysis
The invention provides a line loss multi-source diagnosis method and system based on correlation analysis. The method comprises following steps of according to acquired basic device information, acquisition information and connection information of a power grid, analyzing key factors influencing line losses so as to obtain a multi-factor clustering analysis result; inputting a multi-data source set, carrying out source end system long link transmission, by use of a preset diagnosis rule, carrying out multi-source connection diagnosis and outing a multi-source connection diagnosis result; setting a line loss rate index abnormal threshold, and using a correlation coefficient method to carry out dynamic diagnosis on wiring and line loss index abnormities in courts; and according to the multi-factor clustering analysis result and the multi-source connection diagnosis result, by combining a physical solid-state factor and a dynamic statistical factor influencing the line losses, carrying out correlation analysis composite diagnosis on the line losses of the power grid. According to the invention, line loss management efficiency of source end service departments of the power grid can beeffectively improved.
Owner:北京中恒博瑞数字电力科技有限公司 +1

Bridge bearing capacity evaluation method based on field tested influence line

The invention discloses a bridge bearing capacity evaluation method based on a field tested influence line. The method is composed of such basic methods as a direct calculation evaluation method, a comparison evaluation method, a finite element model modification evaluation method and the like and mainly comprises the following steps: testing the field tested influence line of a bridge structure if the bearing capacity of the bridge structure can not be obtained by the conventional calculation evaluation method; then on the basis of actually measuring the field tested influence line, evaluating the bridge bearing capacity by the three basic evaluation methods of the method; and further evaluating the bridge bearing capacity with the help of such evaluation methods as load test if the evaluation conclusions can not be made by the three basic evaluation methods. The method has the following advantages: the existing bridge bearing capacity evaluation system is supplemented and perfected; and the method is mainly applied to general survey of the technical conditions of the bridges and evaluation of the bearing capacities of the conventional bridges and can also be applied to evaluation of the bearing capacities of special-shaped bridges, bridges for overweight vehicles to pass temporarily and dangerous bridges.
Owner:重庆物康科技有限公司

Similar line-loss division method based on K-MEANS algorithm

ActiveCN104699959AEase of evaluation and comparisonSpecial data processing applicationsElectricityInfluence line
The invention provides a similar line-loss division method based on a K-MEANS algorithm. The similar line-loss division method comprises the following steps: establishing a comprehensive index system influencing line loss and establishing mathematical models of all indexes through the introduction of the comprehensive factors influencing line loss, such as the structural characteristics of all electric grids, the physical parameter of equipment, the running characteristics of the electric grids, the structural characteristics of electricity utilization, and developing situations of the nature and society; using the index values of the electric grids as N-dimensional vectors, performing iterative computation by utilizing the K-MEANS clustering algorithm to obtain the difference between the indexes of the electric grids, so that the electric grids of which the line loss is naturally similar are classified into the same type, and electrical network enterprises can conveniently perform evaluation and comparison on the levels of the line loss of the electric grids of the same type. According to the similar line-loss division method disclosed by the invention, the basic characteristics of the electric grids are sufficiently taken into account, line-loss similar division is performed, the objective rationality of division results is guaranteed, and powerful theory support is provided for line-loss management.
Owner:STATE GRID CORP OF CHINA +2

Method for measuring bridge influence line in uniform-speed passing of vehicle

The invention discloses a method for measuring a bridge influence line in uniform-speed passing of a vehicle. Firstly, according to the passing speed of a tested vehicle and sampling frequency of a sensor, influence line factor points of the tested bridge are determined. Then, dynamic displacement or dynamic strain response is acquired for aiming at the measuring point of the to-be-measured influence line. Finally, a vehicle load matrix is constructed and the bridge influence line is solved. The method settles a problem of incapability of realizing well-posed state in a bridge influence line solving equation, thereby obtaining a more accurate bridge influence line.
Owner:NANJING SOUTHEAST BUILD ELECTROMECHANICAL SEISMIC RES INST

Bridge damage detection method based on strain influence line curvature of elastic constraint beam

The invention discloses a bridge damage detection method based on the strain influence line curvature of an elastic constraint beam. The method comprises the steps of model establishment and analysis,strain influence line analysis and damage identification establishment. According to the invention, boundary conditions with rotation constraint and elastic support are adopted to establish a beam type substructure model with uncertain flexural rigidity and local damage; the analytic expression of the strain influence line of any cross section is deduced; furthermore, the bridge structure damageidentification method based on the difference curvature of the strain influence lines before and after damage is provided, analysis solution proving and numerical example verification prove that the SILC can be used for statically indeterminate bridge damage diagnosis, and theoretical support is provided for application of the SIL method in structure damage diagnosis.
Owner:ANHUI UNIVERSITY OF ARCHITECTURE

Bridge load test quick detection system

InactiveCN107300452ARapid Carrying Capacity AssessmentNo need to worry about permanent damageElasticity measurementInfluence lineCollection system
The invention belongs to the technical field of bridge detection, and discloses a bridge load test quick detection system. The system comprises a wireless strain collection system, a wireless deflection collection system, a wireless load vehicle locating system, a base station receiving system and a bridge bearing capacity evaluation system. According to the bridge load test quick detection system disclosed by the invention, the test cost is reduced; only one load vehicle slowly runs on a planned lane; the system records response data of all detection points in real time and associates the response data with moving positions of the load vehicle in real time; influence lines of all the detection points are obtained through actually tested data; loads with different efficiencies are applied based on the influence lines to estimate the bridge bearing capacity.
Owner:TIANJIN DEVISER ELECTRIC INSTR

Beam bridge damage detection method based on elastic constraint supporting beam corner influence line

The invention discloses a beam bridge damage detection method based on an elastic constraint supporting beam corner influence line. The method comprises the steps of model establishment, corner influence line analysis and damage diagnosis implementation. According to the method, accurate positioning can be achieved based on the elastic constraint supporting beam corner influence line, beam type structure damage is effectively quantified, the relative error is small, and the index noise immunity is good; based on the corner influence line index, adjacent span damage can be diagnosed by arranging corner measuring points on a specific span of the continuous beam bridge, and when the beam end rotation constraint is weak, the damage diagnosis sensitivity is better; according to the method, theproblem that sensors are not easy to install in application based on deflection and strain influence line damage diagnosis can be effectively solved, the proposed influence line loading implementationscheme is reasonable and feasible, quick diagnosis of beam bridge damage can be achieved, and reference is provided for implementation of corner influence line analysis and quick damage diagnosis ofan existing beam bridge.
Owner:ANHUI UNIVERSITY OF ARCHITECTURE

Beam bridge damage detection method based on deflection influence line of elastically restricted supporting beam

ActiveCN110793737AStatic analysis is reasonableStatic analysis availableGeometric CADDesign optimisation/simulationInfluence lineClassical mechanics
The invention discloses a beam bridge damage detection method based on a deflection influence line of an elastically restricted supporting beam. The method comprises the following steps: building a model, analyzing a deflection influence line and concretely implementing damage identification. Specific to defects of a fabricated railway bridge model, the method disclosed by the invention builds anelastically supported boundary beam model with a rotation restraint by combining uncertainty of elastic modulus and sectional dimension of a main beam initial material, so as to simulate a main beam structure of a fabricated railway bridge; by deducing an analytic expression of the deflection influence line of the model and combining finite element example analysis, the deflection influence line method is applied to damage identification study on a fabricated beam structure, influence of a position of a measuring point of the influence line, location and level of a local damage as well as testnoise on an identification result is studied, and a method reference and a study thinking are provided for damage identification and service performance evaluation on an existing fabricated railway bridge structure; and the method disclosed by the invention can be used for identifying occurrence of a local damage of an elastically supported beam with a rotation restraint and accurately determining location of the damage and realizes precise damage quantification.
Owner:ANHUI UNIVERSITY OF ARCHITECTURE

Two-span continuous beam bending moment influence line test experimental device

The invention relates to structural mechanics experimental devices, particularly to a bending moment influence line test experimental device of a continuous beam as the statically indeterminate structure. Vertical DOF (degree of freedom) of two ends of a beam is limited by a pair of double-roller supports which are fixed on a stand, and downward DOF of the middle of the beam is limited by a single-roller support, accordingly forming a symmetrical two-span continuous beam structure; moving load is applied on the beam by a roller with a weight hanging, the roller is pulled by a pull line to an optional position of the left span of the beam, strain sensors are symmetrically arranged on the optional positions of the bottom of the beam and connected with a data collecting device, and through a ruler, load acting position and a measuring point are given accurately. According to the arrangement, under moving load action of the continuous beam, bending moment influence lines generated on different positions are quantitatively obtained, and wide application to the structural mechanics experiments of high engineering colleges is achieved.
Owner:HOHAI UNIV

Determination method of bridge influence line when vehicle passes at non-uniform speed

The invention discloses a determination method of a bridge influence line when a vehicle passes at a non-uniform speed. The determination method of a bridge influence line when a vehicle passes at a non-uniform speed includes the steps: 1) acquiring response vectors of discrete measuring points of a determination influence line as needed; 2) collecting the real-time axle positional information when the vehicle passes a bridge at a non-uniform speed; 3) determining the space between the discrete measuring points of the determination influence line as needed; 4) establishing a position solutionequation of the corresponding set axle every time when collecting response, obtaining the position vector of the corrected set axle, and constructing an axle position matrix; 5) based on the axle position matrix in the step 4), establishing a vehicle load matrix; and 6) based on the response vector and the vehicle load matrix, establishing an equation, and solving the equation to obtain the bridgeinfluence line vector. The determination method of a bridge influence line when a vehicle passes at a non-uniform speed solves the problem that a traditional determination method cannot guarantee that the vehicle can pass the bridge at a uniform speed in the actual test, and solves the ill-posed problem of the bridge influence line solution equation, thus obtaining a more accurate bridge influence line.
Owner:JSTI GRP CO LTD

Determination method and device of bridge reinforcing target bearing capacity

ActiveCN103344395AAccurately estimate real load conditionsAvoid the problem of too rough load effect calculationElasticity measurementInfluence lineBearing capacity
The invention discloses a determination method and device of bridge reinforcing target bearing capacity, and relates to the field of safety of bridges. The determination method of bridge reinforcing target bearing capacity comprises the step of measuring the parameters of each car passing through a target bridge within a set time threshold value, the step of processing the parameters to obtain the load effect value when each car passes through the most adverse position of the target bridge, wherein the most adverse position is the position corresponding to the highest point of a load effect influence line corresponding to the target bridge, the step of processing all the load effect values to obtain a sample space satisfying generalized Paratore distribution and further determine a load effect representative value of the target bridge according to the generalized Paratore distribution rule, and the step of obtaining the target bearing capacity of reinforcing the target bridge according to the load effect representative value. The determination method of bridge reinforcing target bearing capacity can accurately deduce bridge load effect extreme values under the condition of a small calculation cost and reinforce the bridge by utilizing the bridge load effect extreme values.
Owner:TSINGHUA UNIV +1

Method and system for establishing neural network model for determining power grid line loss

The invention provides a method and a system for establishing a neural network model for determining power grid line loss. The method and the system aim at an optimization problem of line loss modeling input. a mutual information principle method is adopted to identify the intensity degree of main factors influencing line loss; then, based on a training set in a sample set of the collected line loss and influence factors, the influence factors are grouped and sequentially substituted into a training neural network model. The method comprises the steps of determining a plurality of neural network models, determining an evaluation index of each neural network model by utilizing a test set in a sample set, and grouping the evaluation indexes to calculate an evaluation index average value so as to determine an influence factor serving as input of an optimal neural network model, thereby improving the line loss prediction accuracy of the established neural network model.
Owner:CHINA ELECTRIC POWER RES INST +4

Uniform-section continuous beam damage identification method for curvature of damaged state support counterforce influence line

The invention discloses a uniform-section continuous beam damage identification method for the curvature of a damaged state support counterforce influence line, and the method comprises the steps: applying a moving load to a damaged beam structure, and obtaining a damaged actual measurement support counterforce influence line; solving the curvature of the influence line, and preliminarily judgingthe damage position through the abrupt change of the curvature curve; removing the curvature value of the damaged position, carrying out piecewise linear fitting on the residual curvature curve to obtain an estimated value of the curvature of the support counterforce influence line before damage, subtracting the estimated value from the curvature of the support counterforce influence line after damage, and further judging the damaged position; conducting damage degree quantification according to the relative change of the estimated value of the curvature of the support counter-force influenceline before structural damage and the curvature of the actually-measured support counter-force influence line after damage; and if a new damage position is found, eliminating the influence of damage on the curvature fitting of the reaction influence line of the support before damage, and quantifying the damage degree again. The method can accurately position and quantify the damage of the uniform-section continuous beam, and is applied to damage evaluation of a beam structure.
Owner:XIANGTAN UNIV

Bridge dynamic impact factor extraction method

The invention relates to the technical field of civil engineering and discloses a bridge dynamic impact factor extraction method to effectively solve the problem of determination of a maximum static value. The method can obtain a more accurate and reasonable bridge dynamic impact factor value, and provides reference for bridge design and management and maintenance and the like. The method comprises the following steps: obtaining dynamic response of a measurement point on a bridge; carrying out piecewise polynomial fitting on the quasi-static portion in the bridge dynamic response, and carrying out superposition fitting on the fluctuation portion in the bridge dynamic response through a series of sine curves; carrying out fitting calculation based on the least squares principle to obtain influence line information reflecting bridge static characteristics; determining a tire-road surface contact force distribution model and a corresponding contact force distribution function; and then, on the basis of the actual bridge inherent influence line information obtained through fitting, and with the contact force distribution function being combined, calculating maximum static response when a vehicle passes the bridge, and calculating the bridge dynamic impact factor.
Owner:CENT SOUTH UNIV

Bridge influence surface identification method considering vehicle wheel load spatial distribution

The invention belongs to the technical field of bridge safety detection, and discloses a bridge influence surface identification method considering vehicle wheel load spatial distribution, which comprises the following steps: 1) loading a bridge with a calibration vehicle by adopting a specific loading path, and collecting response data; 2) numbering the two-dimensional positions of the bridge andestablishing a mathematical model of influence surface identification; and 3) solving the influence surface identification equation by adopting an L2 regularization method. According to the method, actual measurement information of a loading vehicle passing through a bridge of a specific path and bridge response caused by the loading vehicle is utilized, solving is carried out through a bridge two-dimensional position number and a mathematical model established on the basis of the bridge two-dimensional position number, and the influence line recognition precision can be greatly improved; meanwhile, the boundary which cannot be recognized by a traditional method can be effectively reconstructed, and the method has good engineering practical value.
Owner:DALIAN UNIV OF TECH

Steel bridge fatigue evaluation load modeling and fatigue evaluating method

ActiveCN107609317ASolve problems with fatigue assessment loadsGood fatigue assessmentSpecial data processing applicationsInfluence lineElement analysis
The invention discloses a steel bridge fatigue evaluation load modeling and fatigue evaluating method. The steel bridge fatigue evaluation load modeling and fatigue evaluating method comprises, step one, establishing a train load model; step two, processing and classifying measured data; step three, according to the measured data, establishing a probability model for parameters; step four, establishing a train load probability model; step five, generating a random load spectrum through a Monte-Carlo method; step six, through finite element analysis, acquiring stress influence lines of steel bridge fatigue details; step seven, performing influence line loading through the random load spectrum to obtain a stress history; step eight, analyzing the stress history to evaluate steel bridge fatigue. The steel bridge fatigue evaluation load modeling and fatigue evaluating method has the advantages of, through the fatigue evaluation load model which is established on the basis of the measured data for describing the load status of currently-running trains, achieving fatigue evaluation of any component of a steel bridge, establishing a complete train load modeling method, improving the utilization value of the measured data and ensuring more accurate and more practical steel bridge fatigue evaluation.
Owner:RAILWAY ENG RES INST CHINA ACADEMY OF RAILWAY SCI +2

Loading arrangement and adjustment method for bridge static load test

The invention discloses a loading arrangement and adjustment method for a bridge static load test. In combination with a loading shaft weight and vertical marks of influence lines, and through a formula Mk=sigma Fi*Yi, a displacement or internal force calculation value of a test section under the load action of a test car is calculated out; three basic parameters including the number of basic testcars, the coordinates of loading wheel positions and the loading shaft weight Fi are adjusted, so that a ratio of a loading internal force result to a bridge design load internal force result can berapidly obtained, and the ratio is 0.95-1.05; multiple columns of influence line data can be copied to carry out multi-working-condition simultaneous loading calculation; and finally an influence linegraph and a loading graph are drawn. According to the method, an influence line quantity value at any loading wheel position can be quickly obtained; the shaft weight and the coordinates of the loading wheel positions can be quickly changed according to test conditions; and the multi-working-condition loading calculation is carried out simultaneously, so that the loading process of the static load test is greatly simplified, the calculation time is shortened, and the working efficiency of the loading calculation and adjustment of the load test of bridge detection engineers is remarkably improved.
Owner:SOUTHWEST JIAOTONG UNIV
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