抄録
Evaluation (screening) of the seismic performance of RC buildings has been widely carried out in various ways mainly based on the manual issued by Japan Disaster Prevention Association. According to results of the evaluation to date, failure mode of aseismic walls are apt to be estimated as "rotation", in spite of the fact that such failure mode has been hardly recognized in the past disasters, except for the case of collapses due to uneven settlement or liquifation of ground. In the present study, firstly the resisting mechanism of a structure against rotating internal walls is analysed, using the result by "the 3^<rd>-step aseismic evaluation method" for a typical old building of 3 stories. Secondly, the effect of foundation piles on the rotation bearing capacity of seismic walls is discussed. As a result, it is pointed out that the main factors affecting the bearing capacity are resisting forces due to dead load, coupling beams, transverse walls, and foundation piles. In order to change the failure mode of rotation into another one (bending or shear), however, combination of two or more resisting forces due to the above such factors is required.
