抄録
In the previous paper 1) 2), the auther had indicated the difference of the collapse modes between long and short reinforced concrete columns, and had pointed out the existence of the critical shear span ratio value between them. Experimental investigations were carried out to make clear the effect hoops on the improvement of the defornation capacity of short column too. In this paper, analytical researches are carnied out in order to make clear the elastic horizontal sway behaviours of unit reinforsed concrete knee frames with single and double bays subjected to constant vertical loads, which represent the behaviours of real reinforced concrete structures with various column length in the same level. At first, relations between shear force (Q^^-) and relative sway angle (R) of single column (See Fig. 13) are introduced by means of superposition of Q^^-^B-R^B relations (in case of bending) and Q^^-^S-R^S ones (in case of shear), which are given by the general expressions resprectively (See Fig. 12). Then, by the combination of these relations of eachsingle column, the Q^^--R relations of unit knee frames are calculated (See Figs. 14-20). Figs. 21-26 with the parameters α shows this relationships in the more general forms with the values Q^^-_y, R_y of the column H^^-=5 as standard. The general characteristics of this relationships are illustrated in Fig. 30. In case of the knee frame which contains columns with lower shear span ratio than the critical value (Eq. 26 or 27) and without shear ductility, the Q^^--R relation of such a knee frame is indicated by the dotted lines (O-A-A'-B'-C'), and the energy loss may be estimated by the area OBAA'B'C' that should be absorbed by hoops. By this research, the combined bending and shear deformation behaviours of reinforced concrete single columns and of knee frames become clear analytically. As a result, the depression phenomenon of lateral sway capacity of reinforced concrete real frames composed of long and short columns is clarified and it seems to be one of the main reason of the damage of reinforced concrete structures at the Tokachi-Oki earthquake 1968.
