In the present work, free vibration analysis of plane stiffened coupled shear walls is presented based on a discrete-continuous approach, where the structure is considered as both a discrete system and a continuous system at different stages of the analysis. The stiffened system is reinforced by an additional stiffening beam at some level of the structure. This induces additional axial forces, and thus reduces the bending moments in the walls, as well as helping to reduce the lateral deflections and increase the natural frequencies....[ Read more ]

In the present work, free vibration analysis of plane stiffened coupled shear walls is presented based on a discrete-continuous approach, where the structure is considered as both a discrete system and a continuous system at different stages of the analysis. The stiffened system is reinforced by an additional stiffening beam at some level of the structure. This induces additional axial forces, and thus reduces the bending moments in the walls, as well as helping to reduce the lateral deflections and increase the natural frequencies.

A method of analysis is derived for investigating the free vibration characteristics of stiffened coupled shear walls. The results of analysis show that the natural frequencies of vibration of coupled shear walls can be significantly increased and the dynamic performance can be improved by the installation of a stiffening beam. The optimal position for the stiffening beam to increase as far as possible the first natural frequency of vibration is also presented.

The investigation of effects of foundation flexibilities on both static and dynamic behaviors of stiffened coupled shear walls is carried out by considering foundation flexibilities in rotational, vertical and horizontal directions. The results of parametric investigations indicate that foundation vertical stiffness and rotational stiffness have important effects on both static and dynamic characteristics; while horizontal foundation stiffness has little effect and it is normally ignored in the analysis. Based on the discrete-continuous approach in association with the principle of virtual work, the effect of shear deformations is taken into account on the free vibration analysis of stiffened coupled shear walls. The accuracy of the methodology has been verified by experimental investigations of models and study of a realistic structure. Numerical investigations show that shear effects on the fundamental frequencies of stiffened coupled shear walls are slight but on the higher frequencies are significant. Moreover, it is shown that shear deformation of the structural walls, rather than the connecting beams, is the dominating influence on the free vibration characteristics of stiffened coupled shear wall systems.