Simulation Analysis For The Damage Identification Of Reinforced Concrete Arch Bridge On Dynamic Measurement Method

In recent years, a great deal of lower rank roads have been rebuilt and expended in company with the development of economy and traffic construction. It is very important to keep the safety of the bridges in service. A majority of bridges built in 1970's or 1980's aged and damaged in different degree, which results in the decreasing of the load carrying capacity due to overloading and corruption. Bridges in damage are increasing with years. As the bridge has presented the damage, if there are not measures to repair the damage in time, will jeopardize the people's personal security, cause great losses of national economy. Therefore, it has important theory meaning and practical value to go on the research that assess and diagnose the damage of the reinforced concrete arch bridge.The dynamic characteristic of structures has a direct relationship with structural parameters, and structural damage can cause dynamic characteristics shifts correspondently. Therefore, if the mapping relationship between structural damage and dynamic characteristic shifts can be established, the damage can be diagnosed by using dynamic measurements of the structures. According to the measured date and identification principle, the identification methods can divided into the method based on frequency, mode shape, and modal flexibility and so on. But all of those mainly focus on simple structures, it lacks the effective methods of damage identification for the reinforced concrete arch bridge. On the basis of summarizing the related literature of the structural damage diagnose, this paper have Applied four strategy on the basis of the national frequency change ration, camber mode, mode strain energy difference and flexibility difference to diagnoses the damage of the reinforced concrete arch bridge, and carried out a series of comparative analysis, the main research results of the paper are as follows:(1) On the basis of studying domestic and abroad related literature, Have summarized the research overview and the method of the dynamic diagnose method .(2) Access to domestic and abroad related literature, Have summarized the influencing factors of the reinforced concrete arch bridge dynamic characteristics. Have established several finite element models of different span and different types of reinforced concrete arch bridge, and have summarized the vibration characteristics of reinforced concrete arch bridge from modal analysis results.(3) Have established a finite element model of a 120m span reinforced concrete box rib arch bridge, and simulation many kinds of damage state, namely single damage, many places damage, damage the position differently, damage such operating modes as the degree, etc, then utilizing national frequency change ration, caber mode, mode strain energy difference and flexibility difference etc.4 dynamic methods to diagnose these damage. The result of calculation indicates, national frequency change ration can easily determine whether the damage occurred, but can not diagnose the location and the extent of damage; flexibility difference can diagnose except damage near the foot arch; caber mode, mode strain energy difference and flexibility difference can diagnose qualitatively the extent of damage to a certain extent. To increase the reliability of damage identification, you should adopt several ways.