A Practical Method for the Evaluation of In-service Slab-on-girder Bridge Based on Frequency Response Function from Structural Dynamic
Thelow cost,rapid evaluation and further damage identification of in-service bridge can be realized by strengthening the connection between the complex theoretical research of frequency response function and the practice of engineering structure inspection and evaluation.On the basis of the principle of structural dynamic,the simplysupported girder bridgeis taken as an example.The section height coefficient and the elastic modulus coefficient,close to engineering practice,are introduced to characterize the section cracking problems of in-service bridge subjected to the long-term vehicle load effect and the elastic modulus loss problems of in-service bridge subjected to the adverse natural environment,fire and other factors.The natural frequency response function and damage function expression are obtained.The natural frequency response function and the damage function can be used to analyze the change rule of the natural frequency and identify the damage.Study shows that by taking into account the natural frequency response function with the aid of an appearance inspection,a rapid evaluation of the bridge in service can be realized.The classification into five levels of structural natural frequency is also consistent with the five levels of structural performance of in-service bridge in the current code of inspection and evaluation.The frequency is greatly influenced by the damage to the element in the middle section of the girder.While the further damage identification with damage function is more complicated.By replacing the traditional full-scale load test method,this study can reduce the cost of analysis and evaluation,as well as the negative impact on traffic.For damage diagnosis in mechanical and aerospace engineering,the damage identification method herein can also be a reference.
万方数据
