Dynamic behaviour of stiffened coupled shear walls with flexible bases

The free vibration characteristics of stiffened coupled :shear walls with f lexible bases is investigated using a discrete-continuous approach, where t he structure is considered as both a discrete system and a continuous syste m at different stages of the analysis. The stiffnesses of the flexible foun dations are represented by rotational and translational springs at the base of each shear wall. The stiffened system is reinforced by an additional st iffening beam at some level of the structure, This induces additional axial forces, and thus reduces the bending moments in the walls and the lateral deflection, and increase the natural frequencies. The effects of foundation stiffness and the stiffening beam on the free vibration characteristics of the structure are studied. The optimal location of the stiffening beam for increasing as far as possible the first natural frequency of vibration is presented. (C) 1999 Civil-Comp Ltd and Elsevier Science Ltd, All rights res erved.