This paper describes an evaluation of seismic performance of an RC structure with low strength concrete which suffered damages from differential settlement.In this study,at first stage,the differential settlement of the structure was evaluated with the related damages,at second stage,the test of four model frames considered the damages due to differential settlement has been done.,and final stage,the influence of the damages on the structural seismic performance was examined by using the test results of model frames.The following findings were obtained from this study:
(1)Relative deformation angle of the five spans in the both end region of the structure is around 5×10 -3 radian,so that a part of the frame members seem to have been reached to the yield conditions.The central spans of the structure suffered from only a slight damage.
(2)Formula of Ohno-Arakawa used for seismic evaluation have trend to overestimate observed shear strength of columns.
(3)The seismic performance of the structure is affected strongly by the differential settlement.