Abstract
The structural type of building have been changed recently and also there is a tendency to release the height limitation of 31 meters. The movement of reexamination of seismic coefficient has become the object of our earthquake engineers. This report showed at first some example of reinforced concrete columns of 25 story-building or others which are practically designed extending the nowaday's seismic coefficient in Japanese code. As the actual dimention of the columns becomes considerable size in such tall buildings, it is necessary to cut down the weight of buildings or reduce the seismic coefficient inorder to materialize the super-tall buildings. For this purpose the author rearranged the results of dynamic responce of idealized structurs in elasto-plastic state against actual severe earthquakes and showed the probable maximum deflection of structurs as a function of fundamental period of that structurs. As the result the possibility of reducing the seismic coefficient for tall buildings seems to be available.
