Study On Damage Identification Of Spatial Steel Framework

Engineering structure will be damaged during their service period with the affects of various natural and man-made factors. With the damage accumulation, the structure's performance will be degraded or even probably the structure will be destroyed. That's harmful for people's lives and property. Therefore, it is an important issue to detect and locate the damage occurred in structures in much early time.Now, more and more the spatial structures are emerged, even some of them become the landmark of a city or a country. Once these structures are failed, the effects will be vastness. So it is necessary to find and locate the damage as early as possible. In the field of structural damage identification, however, the researches are focused on the beams and the planes, the results could not be used for damage estimation of spatial structures because of their complex performances. In order to find suitable methods for spatial structural damage identification, an intact three-storey space frame and a damaged three-storey space frame are analyzed use the finite element analysis software ANSYS10.0.In this paper, firstly, the recent researches on the structural damage identification are introduced. Secondly, after analyzing the classification and the detection methods of the structural damage, two of the methods (method of analysis element modal strain energy and the two-stage damage identification method based on first mode shape) are selected to detect and locate the damage in structures. Thirdly, by the use of the finite element analysis software ANSYS10.0, a three-storey spatial steel framework analysis model is established, and the modal analysis is carried out by the Subspace method. The damage of the structure is simulated by stiffness reduction method in the model establishing. The first ten frequencies and mode shapes are extracted. Finally, modal parameters of the intact and damaged structure calculated are applied on two methods (element modal strain energy analysis method and the two-stage damage identification method based on first mode shape) to detect and locate the structural damage. The calculating results indicate that two methods are valid in identifying the damage in spatial structure, and accurate in damage location. The conclusions are useful for damage identification and location in spatial framework structures.