Model Test On Damage Detection Of Cable-stayed Bridges For Health Diagnosis

As the development of the times,science technology and material,the cable-stayed bridges gradually turn to the direction of large span and it is a preferred bridge type of long-span bridge.Bridge structure in the long-term operating conditions and the external environment will have a variety of damage.The damage will inevitably lead to structural load capacity and durability declined or even destroy if not timely detection and treatment of ruin.The structure of real-time monitoring has extraordinary significance.This article aims to establish a health monitoring system carried out a few aspects of the works:1.According to the data of long-span cable-stayed bridges at home and abroad,a physical test model of 6m long cable-stayed bridge is designed and manufactured.The model can realize the function of detachable and replaceable components and it can simulate all kinds of working conditions.This model serves as the carrier to establish the structural health monitoring system.The finite element software ANSYS was utilized to calculate calculate the model.The preparation of the experiment was made by preliminaries determining the model of static and dynamic characteristics.2.Model tests.Using a variety of sensor equipment to collect the data.Firstly,the static load test of the stiffening girder and the vehicle static load test is carried out.Built on the finite element calculation results,the consistency of the two parameters is obtained.Secondly,restore the model to the baseline state,the damage of the cable-stayed cable and the damage condition of the main beam under the static load of the cable-stayed bridge was tested.Finally,the model is verified under the load of the vehicle under the load loss test and the cable loss test.3.The analysis of the test results shows that the cable-stayed bridge has regular changes and the structure is in elastic working condition.The damage of the structure can be judged by the parameters such as deflection and strain of the stiffening girder,cable force change rate.It is more convincing and reliable to judge the damage position identification and destroy quantity from the multi-parameter analysis than the single parameter analysis.It is therefore difficult to identify damage to the structure from the change of the natural frequencies.4.Finally,the Wigner-Ville(WVD)distribution cross-term is used to determine the damage.The MATLAB program is designed by using MATLAB time-frequency analysis toolbox.The ruin simulation of the simply supported beam is carried out by ANSYS finite element software,and the cable damage model of the cable-stayed bridge model is carried out.The method can locate the ruin,but it needs to be further studied.