Seismic Performance of Reinforced Concrete Columns from an Existing Building Constructed in 1963

摘要

Experiments were performed on two RC columns taken from a school building that was originally constructed in 1963.The columns were subjected to reverse loading with displacement control under constant axial load.Both columns were.designed with a common shear span length of 1200 mm for the validation of shear capacity equations currently used for seismic evaluation.The concrete of both columns exhibited honeycombs.Thus,one column was repaired with epoxy resin injection,and the effect of retrofitting was investigated.The columns did not exhibit significantly different crack patterns.The collapse mechanism of the two columns were shear failure,and the shear force drift angle response was considerably brittle.The observed values of the original column could be predicted by the recommended standard equations for the strength of shear crack and shear capacity.The maximum strength and the initial stiffness of the retrofitted column were 1.18 times and 1.40 times,respectively,of those of the original column.Results indicated that epoxy resin injection improves the seismic performance of columns of the existing buildings.