Abstract
To identify the damage within retaining wall structures, the Hilbert–Huang Transforms of the impulse response function and virtual impulse response function were performed. The Hilbert marginal energy ratio spectrums of the impulse response function and virtual impulse response function were acquired. To reflect damage information effectively, those bands with stronger damage sensitivity were extracted via the threshold value ε0. Then, the Hilbert feature bands, which were more sensitive to damage within retaining walls, were selected by considering the contribution of the residual band to the damage identification. Based on the feature bands, the Hilbert damage feature vector, which reflects the variations of Hilbert marginal energy ratio caused by damage, was created. Based on the damage feature vector, two damage identification indexes (the energy ration standard deviation and Energy Ration Standard Deviation), which were based on the impulse response function and virtual impulse response function, respectively, were proposed to identify damage within retaining walls. To investigate the validity of the damage indexes, vibration tests on a pile plate retaining wall were done. The test results show that the damage feature vector is a zero vector or the value of damage index is zero when the wall is undamaged. The damage feature vector is a nonzero vector or the value of the damage index is more than zero when the wall is damaged. Thus, the damage state of the wall can be detected sensitively via the damage feature vector or damage indexes. Partial damage causes greater fluctuation of trend surface of the damage index. The location of partial damage can be diagnosed validly via the coordinate of peak value in the trend surface. The quantitative relationship formula between the damage index and damage intensity is established. The damage intensity of the wall can be calculated reversely, when the damage index is available. Either the energy ration standard deviation or Energy Ration Standard Deviation can be used to detect the damage state, diagnose the damage location, and identify the damage intensity. In comparison with the energy ration standard deviation, the stability and damage sensitivity of the Energy Ration Standard Deviation is much better.
Highlights
As a common type of retaining structure, the retaining walls were often used to sustain foundation ditch, stabilize the cutting of highway, and prevent landslide or collapse. us, retaining walls were widely used in building engineering, road engineering, slope engineering, and underground engineering, and so on
To detect the damage state of the wall, the damage index ersd, which is based on IRF, requires that the external excitation and one structural response are available at least. e damage index ERSD, which is based on VIRF, requires that two structural responses are available at least
All the damage feature vectors are nonzero vectors, when holes are drilled in the wall. us, the damage state of the pile plate retaining wall can be sensitively distinguished via damage feature vectors which are based on IRF or VIRF
Summary
As a common type of retaining structure, the retaining walls (such as cantilever retaining walls, gravity retaining walls, and pile plate retaining walls) were often used to sustain foundation ditch, stabilize the cutting of highway, and prevent landslide or collapse. us, retaining walls were widely used in building engineering, road engineering, slope engineering, and underground engineering, and so on. Zhang et al diagnosed the damages within structures via synchronically updating measured vibration modes and finite element model [4]. Zong et al proposed a damage diagnosis method for bridges based on the response surface model updating and the element modal strain energy [5]. Ding et al proposed a damage alarming method for structures based on the Wavelet Packet Decomposition of the virtual impulse response function [12]. E damage identification methods based on the genetic algorithm and neural network were affected greatly by sample functions, objective functions, and algorithms. Based on the damage feature vector, two damage identification indexes (the energy ration standard deviation and Energy Ration Standard Deviation), which are based on the impulse response function and virtual impulse response function, are proposed to identify damage within retaining walls. To investigate the validity of the damage indexes, vibration tests on a pile plate retaining wall are done. e damage within the retaining wall is identified via the energy ration standard deviation and Energy Ration Standard Deviation
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