Failure modes and numerical description of grid structure subjected to earthquake
ZHANG Cheng1 , Wu Hui2 , Gao Boqing1
1.College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China;2.Finance and Economics of Zhejiang College, Hangzhou 310018 ,China
Abstract：Based on large-scale numerical calculations of different forms of grid structure subjected to earthquake, dynamic failure modes and characteristics are analyzed, assuming the failure criteria is maximum displacement exceed 1/50 of the span. Dynamic failure modes of grid structure are determined by four factors: the proportion of 8P bar, maximum displacement during full-time history, the average plastic strain energy, and the ratio of the average and maximum displacement before expiration. As the failure mode is fuzzy, the four factors are analyzed using fuzzy C-means method, and the failure modes are classified into three categories: instability-based progressive collapse, strength-based overall collapse and strength-based progressive collapse, which are described by natural and numerical language respectively. The results show that fuzzy C-means method can effectively classify the failure modes of grid structure, and transform the description from natural to numerical. The numerical prototypes of failure modes are obtained, which can be used to recognize other unknown grids, and lay the foundation for performance-based design.
2011, Vol. 30 
