Rapid Assessment Method Of Bridge Safety Condition Based On Influence Line

As a node project in infrastructure construction,bridge engineering states an important position in economic and society.However,due to the lack of life cycle design and the neglect of the management and maintenance work in the service process,the majority of bridges are damaged with time elapsing.In this condition,it is very essential to come up with a method which can quickly evaluate the safety of the bridge.This paper systematically introduce the traditional assessment methods of bridge safety condition.Emphatically introduce the research status and technical bottlenecks of the assessment methods based on the influence line.On this basis,construct a rapid assessment method system of bridge safety based on influence line which mainly includes the following contents.Reject the axle of vehicle dynamic load effects according to the theory of wavelet change dbN.Extract the unit force-displacement response influence line based on the reciprocal theorem.According to the change of theoretical and practical influence line,construct indicators to assess the safety condition of bridge from coarse-to-fine.This method can obtain the influence line of the bridge without closed traffic,and evaluate the safety state of the bridge according to the change of the influence line,which has the characteristics of economy and efficiency.The reliability of this method is verified by designing vehicle bridge experiment on ChiXi bridge as well as establishing of the finite element model.The test results show that this method can accurately evaluate the service status of chi-tin bridge.By setting different vehicle loading conditions,discuss the influence of load rate and location on this method in practical application.According to the misjudgment and omission of the damage reflected in the test,based on the D-S evidence theory,an optimization method which can improve the confidence of the conclusion through the way of multiple fusion is proposed.In this method,the information source is added by setting up multiple sensors,so as to strengthen the consistency information in the damage judgment.Finally,a bridge safety rapid assessment simulation software for front-line workers is designed to accomplish the process from the measured data to the assessment results.With this software,users can complete the safety status assessment based on this method without learning relevant knowledge.In this way the practicability of the method is improved.