There are still many difficulties in applying the pattern recognition theory to the complex bridge seismic damage identification, for example, it is uneasy to determine damage patterns, and difficult to extract the damage index, and even it is a big challenge to obtain sufficient damage samples. To counter the problems above, a novel bridge seismic damage pattern recognition method based on seismic fragility analysis was proposed. First, seismic excitations were classified into main-shocks and after-shocks. Main-shocks were used to carry out the bridge seismic fragility analysis in order to obtain the potential damage of the bridge, and as a consequent the layout of the sensors and the patterns of seismic damage were determined strategically. After-shocks were used to excite the damaged bridges to obtain their structural responses, and hence the sufficient data samples were acquired. Then, Hilbert-Huang Transform (HHT) was adopted to deal with the structural response data to extract the Damage Index (DI), which was sensitive to structural damage. Finally, the pattern recognition theory was applied to map the relationships between DI and the damage patterns, and the bridge seismic damage identification was achieved. The proposed method was adopted to identify the seismic damage of a continuous rigid frame girder bridge, the results show that the method can identify the bridge seismic damage patterns precisely and the noise immunity of the method is favorable.
SHAN De-shan,ZHOU Xiao-hang, YANG Jing-chao, LI Qiao.
Bridge seismic damage identification based on seismic fragility analysis[J]. Journal of Vibration and Shock, 2017, 36(16): 195-201