Continuous Column Effects of Coupled Shear-Flexural-Beam Models in terms of Static Stability

The continuous column (C.C.) effects, in which elastic columns continuous over structural height prevent story failure mechanism and mitigate the drift concentration in particular stories during earthquakes for steel, reinforced concrete and wooden frame structures. The coupled shear-flexural-beam models, which was proposed and investigated by the author, are simplified models consisting with a shear-beam and a flexural-beam that can consider the C.C. effects explicitly. In this paper, the stiffness matrices of the shear-beam, the flexural-beam and that of the coupled shear-flexural-beam model are derived and their characteristics are investigated in terms of the stability. The eigenvalue analyses are conducted for the 2- and 3-story coupled shear-flexural-beam models at the elastic stage and the assumed 1st-story mechanism is investigated quantitatively to evaluate the C.C. effects on static stability of entire structure.