Patologia estruturas

The Identification of damage in Large Structures
By Alan P. Jeary D.Sc., Ph.D., CEng., FIStructE, FAIB, FRMetS, MAIBS, MIEE. University of Western Sydney, Australia. Introduction It is necessary, when considering the identification of damage in large structures, to be very precise about both what constitutes damage, and of the precise requirements for successful identification. These considerations are not trivial, our classical identification of damage is often unhelpful in an assessment of the state of health of a structure. Additionally, precisely what leads to successful identification of significant damage is a question that bears further investigation. Our appreciation of forensic engineering, as it applies to civil structures, is in its infancy. The tools available to us tend to deal with localized damage, and as such can be of limited used in an overall (holistic) assessment of the structure. Whilst the tools available for structural investigation are technologically good, information available for the assessment of complete structures has to be pieced together from the clues left by investigations using such devices as X-rays, ultrasound, holography, thermography, radar, and eddy currents. In each of these cases the techniques have the advantage of being non-destructive, but a disadvantage of only yielding local information. Tools available for the assessment of complete structures tend to involve destructive techniques. When disassembling a structure is possible to perform a detailed analysis of the state of health of joints within that structure. Clearly the problems associated with destructive testing and do not allow an in-service assessment of the structure. Recently developed techniques, most of which have come from developments from space programs, and system identification of mechanical systems, have recently been used within the civil engineering arena to successfully identify significant damage within large structures. This paper addresses these