After an earthquake, the major concerns to damaged buildings are their safety to aftershocks, quantitative damage assessment to evaluate their residual seismic capacity, and as soon as possible define necessary action on the damaged buildings. Therefore, this research tries to define the reduction factors of seismic capacity for earthquake-damaged RC columns based on the description of damage state in the Damage Evaluation Guideline (JBDPA 2001). For this purpose, several experimental data of columns with various failure mechanisms are used to observe the damage state, to define the limitation of each damage state, and to measure the reduction factors for RC columns. In this study, the seismic capacity reduction factor representing residual seismic capacity is defined as the ratio of residual energy dissipation capacity to the total energy dissipation capacity. Afterward, the relationships between reduction factors and three other factors including damage class, maximum residual crack widths, and drift ratio of residual displacement were obtained from analyses will be compared with the Japanese guideline. Analytical results from experimental data show that reduction factor from guideline generally give conservative value, although some of results are lower than values in guideline. Therefore, this research suggests the new reduction factors of seismic capacity for reinforced concrete columns with various failure mechanisms. Moreover, the validations of reduction factors through calibration with nonlinear dynamic analyses of a SDOF system represent that value of reduction factors are suggested more conservative.

After an earthquake, the major concerns to damaged buildings are their safety to aftershocks, quantitative damage assessment to evaluate their residual seismic capacity, and as soon as possible define necessary action on the damaged buildings. Therefore, this research tries to define the reduction factors of seismic capacity for earthquake-damaged RC columns based on the description of damage state in the Damage Evaluation Guideline (JBDPA 2001). For this purpose, several experimental data of columns with various failure mechanisms are used to observe the damage state, to define the limitation of each damage state, and to measure the reduction factors for RC columns. In this study, the seismic capacity reduction factor representing residual seismic capacity is defined as the ratio of residual energy dissipation capacity to the total energy dissipation capacity. Afterward, the relationships between reduction factors and three other factors including damage class, maximum residual crack widths, and drift ratio of residual displacement were obtained from analyses will be compared with the Japanese guideline. Analytical results from experimental data show that reduction factor from guideline generally give conservative value, although some of results are lower than values in guideline. Therefore, this research suggests the new reduction factors of seismic capacity for reinforced concrete columns with various failure mechanisms. Moreover, the validations of reduction factors through calibration with nonlinear dynamic analyses of a SDOF system represent that value of reduction factors are suggested more conservative.

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