Based On The Dynamic Characteristics Of The Bridge Damage Identification Research

Transport is a lifeline of the country's economic development, and bridges in the country as a whole transportation system plays a pivotal role as well as the throat, so it is critical to ensure the normal use of the bridges and the safety performance, which requires regular safety of bridge detection and long-term health monitoring . On the bridge in safety testing and health monitoring process, the damage identification technology of the structure become a new topic which ngineers faced.Bridge damage identification technology has decades of history,it has been achieved fruitful results in the process, which based on the static and dynamic study. However, one important question is that the dynamic parameters for damage identification are variety, how to ensure that the correct parameters, effectively reflect the true extent of damage location and damage degree of the structure is a serious problem, which requires a combination of scientific rational calculations and parameters of the damage identification, through a series of calculations to conclude the relationships between the dynamic parameters and the damage location and the relationships between the dynamic parameters and the damage degree. It could provide some convenience and serve as a reference for the next damage detection based on these relationships.First of all, this paper introduced the bridge structure damage identification methods and identification theory based on the dynamic properties , and introduced in detail the difference mode shape curvature based on modal analysis of structural damage identification theory.Secondly, this paper compared different modes of simply supported beam, continuous beam mode shape curvature difference columnar section, summarized the best model in which it could identify the damage location clearly.Then, this paper took the simply supported beam and the continuous beam for example, it applicated the large-scale finite element program space Midas and calculated simply supported beam and continuous beam structure in various conditions of the vertical displacement vibration, calculated the difference mode shape curvature which is before and after the structural damage, and draw the relevant columnar section. And evaluated the damage location according to numerical characteristics in the damage unit. Finally, for the simply supported beam and continuous beam to identify the best model by cross-section damage control unit corresponding to different damage conditions of the mode shape curvature and the damage degree, the frequency rate and the damage degree, concluded the relationship between the mode shape curvature and the damage degree, the relationship between the frequency rate and the damage degree.It could be the reference to assess the next damage degree depending on the difference mode shape curvature and the frequency rate of the nodes in the control section.