Research On Damage Identification Of Continuous Beam Bridge Of Equal Section Based On Vehicle-Bridge Coupling Vibration Analysis

Highway bridges play an indispensable role in transportation.With the development of transportation,the traffic volume is increasing,and the requirements for the safe operation of highway bridges are becoming higher and higher.Therefore,Identify the specific damage situation of the operating bridge,provide accurate guidance for the maintenance and reinforcement of the bridge,and ensure that the normal operation of the bridge is more and more worthy of attention.Continuous beam bridges are relatively common bridges in highway bridges,How to identify damage to Continuous beam bridges without affecting the operation of the bridge and without installing a large number of sensors is the problem faced by bridge damage detection.Based on the vehicle-bridge coupled vibration theory,the article selects a quarter vehicle model,aiming at the identification of single damage or multiple damages of three-span continuous beam bridges with equal section.The vibration mode function of the continuous beam bridge can be obtained by fitting the discrete vibration mode data of the bridge through the Cftool module in the Matlab software;then the Matlab software is used to simulate the process of the vehicle traveling through the bridge at a constant speed,and the equation of the vehicle-bridge coupling vibration is solved;Finally,the vibration response of vehicles and bridges at special positions can be calculated.Simulating bridge crack damage with reduction of unit stiffness,first,identify the single damage of continuous beam bridges.Under normal circumstances,the location of the bridge damage or the range of damage is identified according to the position where the vertical displacement response of the corresponding span increases than non-damage conditions when the vehicle travels to each span of the bridge.When the mid-span non-mid position is damaged,the situation is special.The vehicle travels to the mid-span of the bridge,the vertical displacement response of the mid-span is substantially the same as the non-damage conditions or reduced than the non-damage conditions,these two different phenomena also appear in the vertical displacement response of the first mid-span or the third mid-span.Identify the damage location of the bridge based on the critical position of these two phenomena.According to the difference between the vertical displacement response of themid-span and non-damage conditions when the vehicle travels to each span of bridge,the degree of single damage is identified.Then,the multiple damages of the continuous beam bridge are identified and studied.Firstly,the damage span of the bridge is identified according to the position where the vertical speed response of the vehicle body increases than non-damage conditions;According to the difference position between the vertical displacement response of the mid-span and non-damage conditions when the vehicle travels to the damage span of bridge,the bridge damage location or the range of damage is identified;And based on the difference between vertical speed response of the vehicle body or the vertical displacement response of the mid-span and non-damage conditions,the degree of damage is identified.