Structural Damage Identification Based On Deflection Influence Line Of The Arch

The health status of bridge structure has an important influence on the transportation and the development of the national economy, it is of great significance to grasp and judge the operational capacity of the bridges as well as assess the remaining service life of the structure.The accurate location of the damage part and the judgment of the damage extent of the bridge structure can help repair the bridge in time, which is the hot spot in the bridge health diagnosis. This paper point at the arch rib damage of the bridge structure, put forward the damage identification method based on principle of deflection influence line, and test the effectiveness of this method, the main research work is as follows:1.This paper conducts a comparative analysis on several damage identification methods commonly used at home and abroad which include modal vibration mode method, the flexibility matrix method and the inherent frequency method.Firstly introduce the theoretical basis for all kinds of methods, and then set up a single arch structure finite element damage model by the finite element software Midas/Civil to make numerical example to verify the effectiveness of the above methods, lastly compare the advantages and disadvantages of these several kinds of methods.2.This paper introduces the deformation geometric relationship and the vibration theory of the arch structure, and studies the basic principle of deflection influence line method. On the basis of summarizing the predecessors’ research, the arch structure damage identificationmethod that based on arch rib deflection influence line and its first and second order derivative differential were put forward in this paper. The results of the numerical example shows that this method is sensitive to arch structure damage, it can also locate the damage part and assess damage degree effectively.3.This paper studies the optimization layout of the displacement sensor of the damage identification method that based on deflection influence line. It makes measuring point optimal calculation of the arch structure in different conditions by using the effective independent and improved effective independent method, and use Midas to make check calculation, compared with simply supported beam, the results show the difference with simply supported beam, the deflection near 1/4 span arch structure affect the line width value is bigger, which is easy to measure.4. This paper conducts a large number of damage identification experiment of single arch model. Under laboratory conditions, use the deflection influence line method to do arch structure damage identification in different working conditions, and compared the effects of different measuring point to the damage identification. The experiment results showed that the second derivative difference of deflection influence line can locate damage and judge the damage degree effectively. It presents great difference of the deflection influence line amplitude in different measuring points. Selecting the deflection line of reasonable measuring points to settle damage identification problems provides a new approach for arch structural damage detection.