This paper discusses following subjects related to elasto-plastic behaviors of tall buildings for across wind action by numerical response analysis with multi-mass models with equivalent shearing stiffness. Firstly, to clarify the applicablity of the suggested response analysis method with one-mass model, effects of higher mode vibrations and changes of mode shapes with the progress of structural yielding are examined. Secondly, the applicability of the mode correction factor which is often used in a case of elastic response analysis is examined. And lastly, energy distribution properties for elastic and elasto-plastic vibrations are discussed, and a simple estimation method is presented. Obtained major findings are as follows; 1. Effects of higher mode vibrations and changes of the first mode shapes are very small. 2. The mode correction factor about the first generalized wind force, which has been used is elastic response analysis, is applicable for elasto-plastic response analysis. 3. Distributions of total input energy are approximately similar to them in elastic responses except for peculiar cases of distribution of the elastic limit of inter story deflection in bending type buildings.
