Fire behaviours of concrete columns with prior seismic damage

To investigate the fire behaviours of earthquake-damaged concrete columns, eight reinforced concrete specimens were subjected to cyclic loadings at room temperature. The pre-damaged specimens and one control specimen without pre-damage were then tested in an ISO 834 fire. The experimental parameters of the columns included the intended drift ratio, axial load ratio, volumetric transverse reinforcement ratio and shear span ratio. The test results revealed the following. Compared with the drift ratio, the axial load ratio had a more significantly adverse effect on spalling of the column's concrete cover during the cyclic loading test. When the axial load ratio was 0·5, the influence of drift ratio in the range 0 to 1/65 on the fire endurance of the pre-damaged columns was limited, but fire endurance dropped dramatically for a drift ratio of 1/40. When the axial load ratio was less than 0·25, the fire endurance of the pre-damaged columns was still satisfactory even for an extremely large drift ratio (e.g. 1/26). The fire endurance of the pre-damaged columns increased to some extent with a reduction in shear span ratio.