Most of the past studies on the seismic response of asymmetric buildings have concentrated on
structures with uniform distribution of mass and stiffness along the building height. Such results clearly
do not apply to many modern buildings with a transfer plate system at lower levels. This paper proposes
a simple but yet reliable formulation, capable of analyzing the seismic vibrations of irregular tall
buildings with varying mass and stiffness along the building height. More specifically, the building is
divided into storey. Within each storey, all wall and frame members are replaced by an equivalent
flexural beam located at the center of flexure and an equivalent shear beam located at the center of shear,
respectively. Different storeys are connected through continuity conditions. Finally, the governing
equations of coupled vibrations are established and the results of a simple example are discussed. More
detailed analysis will be conducted in the near future. Nevertheless, the present formulation should
provide a more reliable way to assess the seismic vulnerability of non-uniform tall buildings in Hong
Kong and other regions of moderate seismicity
