The quantitative damage index considering structural types are essential for the effective post-earuthquake safety evaluation. This paper is the fundamental research in order to present the quantitative damage index for reinforced concrete members with non-seismic details. The crack width changes related with seismic response were studied based on the static test results of one-span and -story specimen with non-seismic details. According to the test result, cracks mostly occurred on the beam-column joints and the upper-and lower-part of columns. The flexural crack width on the column end section and shear crack width on the upper column were widely opened by loading. The residual crack widths were also getting larger since yielding of reinforcements. Meanwhile, the maximum residual crack width was lower than the 1/2-fold of the maximum crack width before yielding, and got the 1/6-and 1-fold of the maximum crack width after yielding.