The Research On Dynamic Rapid Assessment Method Of Concrete Girder Bridge

Load test for the evaluation of bridge while it is possible to fully reflect the actualworking condition of the structure, but the cost is larger, so fast evaluation method ofdynamic measurement test has become the research hot spot. Due to the dynamic evaluationmethod for reinforced concrete structure can reflect its structure under moving load and theactual working condition, so the dynamic test method and the research and application ofsystem identification theory has a broad prospect. In this paper, the driven static test, toexplore the feasibility of reinforced concrete rectangular beam rapid dynamic evaluation.This paper expounds the dynamic damage identification method of typical impact the basictheory of elastic wave testing technique, vibration spectrum of the test and analysis methods.Based on the above theory to the design of the model test, including the parameters of theexperimental beam, the arrangement of measuring point, experimental process and dataacquisition, etc.The strength of the tested beam by measured the rebound value calculation, testingvarious working conditions of beam loading process strain contours, fracture developmentand distribution characteristics, calculate the width of crack size, and test out of the ultimatebearing capacity of the beam body destroyed, and comprehensive analysis of beam bodyfeatures from elastic stage to destruction during work.The impact of the elastic wave test and strain distribution and fracture characteristics ofthe analysis of beam, the law is summed up in the beam body in front of the test load,produced by the hammer impact there is a tiny difference of the initial elastic wave signal.When using the two orders of magnitude smaller load of beams after repeated load, elasticshock wave signal measured by the results of vibration prior to the time difference and thebeam body empty, there is no obvious change. After the girder cracks, elastic wave signalappeared obvious difference, the difference is mainly with the distribution of crack locationand the size of the crack width. In this way, can be achieved for structure integrity detection,identify the damage location and damage degree of size.Based on the biggest impact dynamic deflection of the beam span test, to calculate thetransient impact of curvature at the smaller level, and the curvature of the destruction of backrest is elastic stage, which is a reflection of the dynamic displacement on the other hand.Moreover, by means of the multivariate linear regression analysis, mathematics, themaximum dynamic deflection of beam body transient shock and there exists a linear relationship between the ultimate bearing capacity of beam. Experimental beams in the failurestage is a flexible work stage across the largest impact dynamic deflection increment to acertain extent, there exists a linear relationship between the increment and the crack width.Thus, in determining the impact loads, structural damage before and after the dynamicdeflection increment can identify the size of the structural integrity and damage degree.Based on the research results, the establishment of a set of reinforced concrete and prestressedconcrete girder bridge dynamic assessment method, to the actual bridge structure safetyperformance rapid assessment provides guidance.