FRAGILITY FUNCTIONS FOR REINFORCED CONCRETE COLUMNS

A database of reinforced concrete (RC) frame columns that satisfy the requirements of Chinese codes is established based on the literature research. Six damage states and the corresponding repair methods are proposed for RC columns. Based on the FEMA P-58 method, the fragility functions are developed with the rotation angle as the engineering requirement parameter. The quality of the fragility functions is evaluated by comparison with the of FEMA P-58 fragility functions. The effects of seismic grades and axial load ratios on the fragility function parameters and fragility curves are also discussed. The results show that the quality of the proposed function functions is good. The median values of the fragility functions corresponding to the damage state range from 0.764% to 4.52%, and the logarithmic standard deviations range from 0.339 to 0.425. Taking the seismic grade as a variable, the maximum differences between the fragility curves of the frame columns at the third/fourth seismic grade and the frame columns at the first seismic grade are11.79% and 15.39% under the low and high axial load ratio, respectively. Taking the axial load ratio as a variable, the maximum difference between the fragility curves of columns with high and low axial load ratio reached 42.61%, 37.11%, and 43.37% for the columns at the first, second and third/fourth seismic grade, respectively. The results of this paper can be used in the seismic loss assessment and resilience analysis of RC building structures in China.