Abstract
Structural pounding can cause considerable damage and even lead to collapse of structures. Most research focuses on modeling, parameter investigation, and mitigation approaches. With the development of structural health monitoring, the on-line detection of pounding becomes possible. The detection of pounding can provide useful information of potential damage of structures. This paper proposed using wavelet scalograms of dynamic response to detect pounding and examined the feasibility of this method. Numerical investigations were performed on a pounding system that consisted of a damped single-degree-of-freedom (SDOF) structure and a rigid barrier. Hertz contact model was used to simulate pounding behavior. The responses and pounding forces of the system under harmonic and earthquake excitations were numerically solved. The wavelet scalograms of acceleration responses were used to identify poundings. It was found that the scalograms can indicate the occurrence of pounding and occurrence time very well. The severity of the poundings was also approximately estimated. Experimental studies were carried out, in which shake table tests were conducted on a bridge model that underwent pounding between its different components during ground motion excitation. The wavelet scalograms of the bridge responses indicated pounding occurrence quite well. Hence the conclusions from the numerical studies were verified experimentally.
Highlights
The different phase vibrations of neighboring buildings or adjacent parts of the same building or bridge can result in pounding under earthquake excitation if the separation distance between them is not sufficient
The primary objective of this paper is to investigate the applicability of wavelet scalograms in seismic pounding detection
The accelerations recorded by accelerometer a4 for both test sets with and without shape memory alloy metal rubber dampers (SMAMRDs) were analyzed by wavelet scalograms
Summary
The different phase vibrations of neighboring buildings or adjacent parts of the same building or bridge can result in pounding under earthquake excitation if the separation distance between them is not sufficient. The existed pounding research concentrated on modeling of pounding systems, parameter investigations, and mitigation approaches. This paper proposed to use wavelet scalograms to detect the occurrence of pounding. Wavelet scalogram is square of the modulus of the wavelet transform It can uncover previously concealed information about the nature of nonstationary processes. The primary objective of this paper is to investigate the applicability of wavelet scalograms in seismic pounding detection. The Hertz contact model was introduced into the pounding modeling, and the properties of a large-scale bridge segment were used for an SDOF concrete structure while the appropriate value of an impact stiffness parameter was calculated. The responses of the pounding system between the SDOF structure subjected to harmonic and earthquake excitations and a stationary rigid structure were computed and processed to obtain wavelet scalograms. The effectiveness of the wavelet scalogram in identifying seismic pounding was studied
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