Abstract
The column footings of the frames with shear walls subjected to incremental lateral load often up-lift from underlying soil, because of the concentration of the load on walls. This paper examines the properties of the frames with shear walls, considering up-lift of column footings and elasto-plastic behavior of all members and of soils. The soil under individual footing is assumed to be a horizontal spring (K_H), and a vertical one (K_V) which can not resist a tension. The analytical technique is based on the displacement method of the stiffness matrix analysis, proposed in part 1. The results of the analyses are summerized as follows. The stiffer the underlying soil is, the more easily occurs the up-lift of the column footing shear wall, which deteriorates greatly the horizontal strength of frames. The yield of the beams occurs earlier than the up-lift for small K_V, but for large K_V this occurs earlier than that. The maximum strength of the frame is about the same value in spit of the stiffness of the soil. Lateral load bearing capacity of shear walls, which are lower stories, does not so deteriorate notwithstanding the up-lift of the footing of walls, and that is greatly influenced by the strength of the soil and of the beams whose one ends are bounded by walls. When the frame touched the maximum strength, lateral load bearing capacity of shear wall with an up-lifted footing is about the same value in any case of K_V.
