Dynamic Behavior of Reinforced Concrete Structures with Masonry Walls

The inclusion of a soft storey in multistory concrete buildings is a feature gaining popularity in urban areas where the cost of land is exorbitant. In earthquake prone zones, this feature has been observed in post-earthquake investigations. Although engineers are prepared to accept the notion that a soft storey poses a weak link in Seismic Design, yet the idea demands better understanding. The following study illustrates the importance of the judicious distribution of shear walls. The selected building is analyzed through nine numerical models which address the behavior of framed structures. The parameters discussed include, inter alias, the fundamental period of vibration, lateral displacements and bending moment. It is noticed that an abrupt change in stiffness between the soft storey and the level above is responsible for increasing the strength demand on first storey columns. Extending the elevator shafts throughout the soft storey is strongly recommended.