Finite Element Analysis Of The Curvature Mode Theory-based Research Bridge Damage Diagnosis

With the rapid development of communication industry in our country, density of highways network improves constantly and the large span bridge is emerging constantly. But structural damages such as cracking and aging etc. to some degree during the bridge structures service life occur from time to time. Some invisible damages do not alert the engineers in time and may result in disastrous consequences and ultimately cause substantial loss of life and property. Therefore, it is important to command the health status of bridge in commonly using state in time and to detect damages at the earliest possible stage.In this paper, based on analyzing the present researches and existing problems of the dynamic method of the damage identification in engineering structure, the curvature modal method of damage identification in structure is discussed. The main work is briefly mentioned as follows.(1) Introducing the existing methods of the safety evaluation of bridges.several damage identification methods used to identify the bridge structural damage theory are discussed and analyzed.(2) Considering that Curvature Mode can identify the damage of structures and can show the change of local state of bridges and it can be used to inspect the location and degree of damage. The theoretical basis was developed emphatically for the curvature modal analysis and the curvature mode properties in the paper. The relation between the curvature mode and the strain mode for structures such as bridges subjected to bending and vibration was discussed. The curvature mode is rather sensitive to the local change of structures. And the results show that the curvature mode will be more conveniently used than the strain mode.(3) This thesis introduces the finite element theory of reinforced concrete's structure model briefly. The basic finite element theory contains:method and process of the finite element theory, and the common use element form. All the theory mentioned in this section provided theoretical principle and design parameters for the later finite element modeling in practical engineering.(4) The thesis states the whole process of making large-size RC analysis by using large finite computer software ANSYS. And based on curvature mode theory used in damage diagnosis, a finite element model referred to a pre-reinforced concrete beam is built in this paper to be studied.Finite element analysis shows that curvature mode is a sensitive index in damage diagnosis for whole bridge structure or for pant of it. Some useful conclusions for girder bridge is built in this paper can serve as references for real bridge damage diagnosis.But it also has the deficiency:curvature modal method tends to be influenced by the measure errors. So, before applying the method to the real engineering structures, there will be still a large amount of work to do.