The Studies On Damage Detection Of Structures Based On Strain Mode

The engineering structure cannot avoid damage like micro-crack or micro-hole and so on, under outer effects such as load, temperature, corrosion. The structural damage detection can help people to take measures of strengthening as early as possible so as to reduce the accumulation of structure damage resulting in reducing the accident incipient fault.This paper summarizes the current study situation on damage detection of engineering structure, discusses the methods of structural damage detection based on strain mode and its application on damage detection of cases of large-size complicated reinforced concrete structure. The main points are following.Synthesizing the study achievement of strain mode theory, a brand-new analysis method upon test data is laid out in this paper. First of all, amplitude frequency response characteristics of each measure point which is processed by noise reduction processing through filtering wave and Fast Fourier Transform, and then, natural frequency of every rank of the test object is come out through finite element analyses. Based on data foregoing, the whole field of frequency is divided into sectors which contain natural frequency of every rank; the next step is to program the computer software which can search every sector to get the actual frequency and its amplitude of every rank. Finally, the strain mode shape corresponding to natural frequency of every rank is come out through cubic spline interpolation.This paper also designs and manufactures damage-prefabricated test structure including metal beam with simple constitutive relation and definite support conditions and complicated reinforced concrete box gird. Location of structure damage is realized through theory analysis, numerical simulation and model experiment. And a set of effective detection scheme is figured out.Further more, this paper assesses the situation of an active service bridge by processing the dynamic strain test data using the damage detection method base on stain mode. All these work devotes to experiences accumulation in damage detection upon large-size complicated structure.