Performance-based Seismic Design And Damage Assessment For Square Concrete-filled Steel Tubular Structure

Performance-based seismic design theory was proposed by American and Japanese researchers in the early 1990's ,which was in the light of seismic disasters in recent years.And revising the seismic design code all over the world has become the mainstream in 21st century.The objective of performance-based seismic design is to control structure damage,economic loss and casualties caused by earthquake under expectant goal, and maintain the functions of buildings after seismic shock. With the deepness of cognition and research, the performance-based seismic design method is widely used. After the Wenchuan earthquake, seismdogists pay more attention to seismic design theory. So further research and reflection is still needed. The attention degree to the performance-based seismic design theory will be enhanced. Because of excellent seismic behavior, concrete-filled steel tubular structure is more and more employed in high-rise buildings, especially super high-rise buildings. Some scholar consider that the performance-based seismic design theory can be suitable for the design of super high-rise buildings. And the theory is used for the design of the super high-rise buildings is becoming mature. Refering to square concrete-filled steel tubular structure and combining with performance-based seismic design theory, the major goal of this thesis is as follows:1. The theory about the performance level relative to the skeleton curve is proposed in this thesis. Based on this theory, the test data of the square concrete-filled steel tubular column are arranged. The performance level of the square concrete-filled steel tubular structure is established after the statistical analysis.2. The displacement-based seismic design method of square concrete-filled steel tubular column is proposed in the thesis. In this theory, the yield displacement is determined by the geometrical scale without the iteration. Some problems in the performance-based seismic design of square concrete-filled steel tubular column are discussed in this thesis, mainly including: determination the hysteretic damping coefficient of square concrete-filled steel tubular column; simplified calculation method of strength of square concrete-filled steel tubular column;.the selection of the inelastic displacement response spectrum.3. The feasibility of performance-based seismic design theory of the square concrete-filled steel tubular column is verified through an example. The damage-index formula is fitted based on the test data. Then the relation between the formula and the performance-based seismic design is proposed. The performance-based evaluation method of the square concrete-filled steel tubular column is put forward in this thesis.