The study reported herein is to investigate the seismic safety of medium-rise apartment houses of RC wall structure type by means of a full scale testing program. In Japan more than 700,000 apartment houses of low-rise RC wall structure, mainly less than five stories, have been already constructed. Their seismic safety, through structural experiments and studies of earthquake damages, have been confirmed to be synthetically excellent primarily because of their enough lateral resistant strength which compensates the insufficient deformation capacity.

On the other hand, the demands for realization of construction of medium-rise RC wall structure with eight stories have been extensively raised due to the change on land use situations (tremendous increase of the cost of land area). Under these circumstances an outline of the new design Code for medium-rise RC wall structure was proposed in 1979.

In this new proposed design Code, the principle to require ductile deformation capacity to compensate the less strength than that of the past low-rise RC wall structure was specified. For this purpose, following several regulations for structural design improving deformation capacity were provided, i.e. to make stiffness of every shear wall as uniform as possible, to restrict the number of members anticipated to fail brittly,and to set the minimum requirement of shear reinforcing ratio.

Testing on the model structure designed according to this new proposed Code was conducted. Consequently it was obtained that ultimate strength of building was more than 50% of its total weight, and deformation capacity was also satisfactory.