ارزیابی آسیب پذیری لرزه ای احتمالی
Abstract
1-Introduction
2-Analysis modelling
3-Sensitivity study of modelling parameters
4-Probabilistic seismic demand analysis
5-Probabilistic seismic capacity analysis
6-Probabilistic seismic fragility analysis
7-Conclusions
Acknowledgments
Appendix A.
References
Abstract
Single-layer aluminium alloy cylindrical shells are established using the powerful finite element (FE) software package ABAQUS. Furthermore, the probability distribution models of different random parameters in structural modelling are summarized. Forty seismic ground motion records are selected to consider the uncertainty of earthquakes. Sensitivity analysis of modelling parameters is conducted to determine the parameters with the greatest influence on seismic responses. The incremental dynamic analysis (IDA) method is performed on aluminium alloy cylindrical latticed shell structures with different structural parameters. After applying the damage index and structural performance levels of the latticed shells proposed in this paper, the probabilistic seismic demand model and probabilistic seismic capacity model are established. The seismic performance and the collapse capacity of different aluminium alloy cylindrical latticed shells are discussed based on the FE results. Furthermore, vulnerability curves are obtained according to the IDA results, which can be utilized to predict the failure probability and to evaluate the structural performance of aluminium alloy cylindrical latticed shells under different levels of earthquakes.
Introduction
Aluminium alloys have become a widely applied construction material in transportation applications in the aviation, aerospace, automobile, mechanical manufacturing, shipbuilding and chemical industries [1]. In recent years, they have developed into an important substitute of structural steel, especially for light structures, such as long-span spatial structures, tower structures and bridges [2]. The increase of aluminium alloys in spatial structures, such as reticulated shells, is a result of their superior characteristics to structural steel, such as their low density, high strength-to-weight ratio, low maintenance costs and good recyclability. These alloys also provide comparable ease of manufacturing and superior aesthetics. Many representative aluminium reticulated spatial structures have been established in the United States, Europe and China [3–۴]. Most aluminium reticulated spatial structures are single-layer reticulated shells. Due to their importance and specialty to building functions, once the reticulated shells are damaged or collapse, a large direct or indirect economic loss or casualty results. However, the Chinese seismic code only aims to achieve the performance level of life safety, which is not capable of satisfying users’ needs. The analysis of the seismic fragility of aluminium reticulated shells both provides theoretical support to the performance-based seismic design and lays the foundation for the evaluation of seismic loss.